ML20033A207
| ML20033A207 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 10/31/1978 |
| From: | NORMANDEAU ASSOCIATES, INC. |
| To: | |
| Shared Package | |
| ML20033A174 | List:
|
| References | |
| VIII-3, NUDOCS 8111240911 | |
| Download: ML20033A207 (81) | |
Text
-
r SEABROOK ENVIRONMENTAL STUDIES, 1976-1977 MONITORING OF PLANKTON AND RELATED PHYSICAL-CHEMICAL FACTORS TECHNICAL REPORT VIII-3 Prepared for PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE Manchester, New Hampshire by NORMANDEAU ASSOCIATES, INC.
Bedford, New Hampshire October 1978 8111240911~ ettiti PDR ADOCK 05000443 C
TABLE OF CONTENTS PAGE
1.0 INTRODUCTION
1 2.0 METHODS.......................
4 2.1 FIELD COLLECTIONS..................
4 2.1.1 Net Tows: tieso (Mid-Sized) Zooplankton.......
4 2.1.2 Pumped Samples: Microzooplankton and Net Phyto-plankton.......................
4 2.1.3 Water Chemistry..
4 2.2 LABORATORY ANALYSIS.................
6
?.2.1 Net Phytoplankton..................
6 2.2.2 Zooplankton.....................
6 2.2.3 Chlorophyll a.
7 2.2.4 Carbon-14 Uptake...................
8 2.2.5 Plant Nutrients...................
8 2.3 DATA ANALYSES....................
8 3.0 RESULTS.......................
10 3.1 NET PHYTOPLANKTON..................
10 3.1.1 Numerical Abundances.................
10 3.1.2 Species Composition.
10 3.1.3 Seasonal Differences in Species Composition.....
15 3.1.4 Spatial Distribution...
15 3.1.5 Chlorophyll a.
21 3.1.6 Primary Productivity.................
21 3.1.7 Plant Nutrients...................
21 3.2 ZOO P LAN KTON.....................
26 3.2.1 Species Composit'On..
26 3.2.2 Seasonal Distribution..............
28 3.2.2.1 General...................
28 3.2.2.2 Holoplankton...............
31 i
1 PAGE 3.2.2.3 Meroplankton...
35 3.2.3 Spatial Distribution..
38 3.2.4 Biomass.......................
38 4.0 DISCUSSION......................
43 4.1 PHYTOPLANKTON....................
43 4.1.1 General.......................
43 4.1.2 Indicator Species..................
43 4.2 ZOOPLANKTON...
46 4.2.1 General.......................
46 4.2.2 Indicator Species..................
50 5.0
SUMMARY
58 6.0 LITERATURE CITED...................
60 7.0 APPENDICES......................
62 ii
LIST OF FIGURES PAGE 2.1-1.
Plankton sampling stations..............
5 3.1-1.
Total net phytoplankton abundances; means of four replicates each station and month..........
12 3.1-2.
Numerical abundance of Skeletonema costatum, means of four replicates.
Standard deviations shown except where less than.10..............
17 3.1-3.
Numerical abundance of Chaetoceros debilis, means of four replicates.
Standard deviations shown except where less than.10..............
18 3.1-4.
Numerical abundance of Ceracium longipes, means of four replicates.
Standard deviations shown except where less than.10..............
19 3.1-5.
Mean densities by station and depth of 10 taxcnomic components of net phytoplankton assemblages in the vicinity of Hampton Beach, New Hampshire.......
20 3.1-6.
Chlorophyll a concentration (means and standard deviation) at Stations 1, 2 and 5..........
22 3
3.2-1.
Mean zooplankton abundance (no./m ) by collection date.........................
29 3.2-2.
Percentage contribution to total abundance by holo-planktonic, meroplanktonic and tychopianktonic forms for each collection date...............
30 3.2-3.
Seasonal abundance of copepodites representing six species of calanoid copepods.............
32 3.2-4.
Mean abundance of Pseudocaianus minutus 1ife stages by station.
Standard deviations shown except where less than.25....................
33 3.2-5.
Mean abundance of Furytemora herdmani life stages by station.
Standard deviations shown except where less than.25....................
34 iii
PAGE 3.2-6.
Seasonal abundance of four life stages of Ch7mna spp..........................
36 3.2-7.
Mean densities by station of 11 zooplankters in bor.go net tows from the vicinity of Hampton Beach, New Hampshire.
Data represent sexually mature adults except where otherwise inuicated.......
39 3.2-8.
Mean densities by station and depth of 12 taxonomic components of pump zooplankton assemblages in the vicinity of Hamp.on Beach, New Hampshire.......
39 3.2-9.
Mean density, by station and depth, of various life stages of C M.cna spp.................
40 3.2-10.
Means and standard deviations of mesozooplankton biomass (mg/m 3 dry weight), and mean numerical 3
abundance (per m ) by station and collection date for bongo net tows..................
41 iV
LIST OF TABLES q
PAGE-3.1-1.
TOTAL NET PHYTOPLANKTON ABUNDANCE (CELLS / LITER)
MEANS OF FOUR REPLICATES, EACH STATI)N AND DEPTH...
11 3.1-2.
ABUNDANCE, RANK, ANNUAL PERCENTAGE COMPOSITION AND FREQUENCY OF OCCURRENCE OF NET PHYTOPLANKTERS COLLECTED IN THE VICINITY OF HAMPTON, NEW HAMPSHIRE, JULY 1976 THROUGH JUNE 1977.............
13 3.1-3.
NUMERICAL ABUNDANCE (CELLS / LITER) of NET PHYTOPLANMTON DOMINANTS (COMPRISING 10% OR MORE OF TOTAL CELL COUNT, ON ONE OR MORE COLLECTION DATES), AVERAGED OVER ALL STATIONS AND DEPTHS.................
16 3.1-4.
PRIMARY PRODUCTIVITY, RATIO OF PRODUCTIVITY TO BIOMASS AND CARBON SPECIFIC PHYTOPLANKTON GROWTH RATES AT STATION 5..................
23 3.1-5.
PLANT NUTRIENT CONCENTRATIONS BY STATION AND SAMPLING DATE....................
24 3.2-1.
ABUNDANCE, RANK, ANNUAL PERCENTAGE COMPOSITION AND FREQUENCY OF OCCURRENCE OF ZOOPLANKTFRS COLLECTED IN THE VICINITY OF HAMPTON, NEW HAMPSHIRE, JULY 1976 THROUGH JUNE 1977................
27 3
3.2-2.
MEAN ABUNDANCE (PER M ) 0F IMPORTANT INVERTEBRATE TAXONOMIC GROUPS IN THE MEROPLANKTON, BY COLLECTION DATE.........................
37 3
4.1-1.
MONTHLY CHLOROPHYLL a CONCENTRATION DATA (mg/m )
FROM VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION....
44 I4 3
4.1-2.
C UPTAKE MEASUREMENTS (mgC/m /hr) IN THE VICINITY OF THE PROPOSED DISCHARGE SITE............
44 4.1-3.
MONTHLY NUTRIENT DATA FROM VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEA-BROOK STATION....................
45 V
PAGE 4.1-4.
MONTHLY DATA ON THREE PHYTOPLANKTON INDICATOR SPECIES IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEA-BROOK STATION, 1972-1977...............
47 3
4.2-1.
MONTHLY ESTIMATES OF ZOOPLANKTON BIOMASS (mg/m DRY WEIGHT) VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION....
49 4.2-2.
RELATIVE REPRESENTATION OF HOLOPLANKTERS IN THE VICINITY OF MAMPTON BEACH, NEW HAMPSHIRE.
COMPARISON OF 1976-1977 ABUNDANCE RANKING WITH PREVIOUS YEARS..
51 4.2-3.
MONTHLY DATA ON OIIE0JA SPP. NUMERICAL DENSITY 3
(INDIVIDUALS /m ) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION........
53 4.2-4.
MONTHLY CATA ON PSEUDOCALANUS MINUIUS ADULT NUMERICAL 3
DENSITY (INDIVIDUALS /m ) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION...........
54 4.2-5.
MONTHLY DATA ON EURYTEMORA HERDMANI NUMERICAL DENSITY 3
(INDIVIDUALS /m ) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION...........
55 4.2-6.
MONTHLY DATA ON CALANUS FI?2!ARCHICUS COPEP0DITE 3
NUMERICAL DENSITY (INDIVIDUALS /m ) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION...
57 vi
SEABROOK ENVIRONMENTAL STUDIES, 1976-1977 MONITORING 0F PLANKTON AND RELATED PHYSICAL-CHEMICAL FACTORS TECHNICAL REPORT VIII-3
1.0 INTRODUCTION
A plankton preoperational m nitoring program was formally implemented, as of July 1975, to facilitate evaluation of the impact of Seabrook Station on composition and distribution of phytoplankton and zooplankton populations, particularly with regard to the intake and discharge of cooling water off Hampton Beach, New Hampshire.
In a previous report that 1) summarized plankton studies that began in the summer of 1969, and 2) presented results of the first formal year of preoperational monitoring, Normandeau Associates, Inc.
(1977a) described coastal New Hampshire phytoplankton and zooplankton assemblages as resembling those found at most other near-coastal loca-tions in the Gulf of Maine.
The net phytoplankton assemblage in the Gulf of Maine and spe-cif3cally in coastal New Hampshire has been described as being largely composed of diatoms and armored dinoflagellates.
Diatoms exhibit a typical semiannual cycle of spring and fall maxima, and winter and su=ter minima. Dinoflagellate population maxima tend to occur during the warmer months. Maximum concentrations of the key plant nutrients, nitrogen and phosphorous, were shown to have occurred in winter, when low light levels tend to limit phytoplankton growth.
Certain net phytoplankton species were selected for particular emphasis because they appeared consistently among the more common phyto-plankton organisms collected year after year.
Historically, these indicator species, and the seasonal preferences they exhibited have 1
2 Y
e been as follows: Skeletonema costatum, late summer and late fall; Chaetoceros debilis, springs and Ceratium longipes, early summer.
Patterns of zooplankton abundance were found to be more com-plicated. Populations of holoplankton (planktonic animals which spend their entire life in the water column) tended to follow the phytoplank-ton peaks. Undoubtedly the reason for this was that most holoplankters collected have been herbivorous or omnivorous copepods. Four indicator species have historically exhibited the following distributional trends:
Oithona similis, ubiquitous; Eurytemora herdmani, inshore and in summer; Pseudocalanus minutus, offshore, and in late summer and fall; and Cala-nus finmarchicus, offshore and from spring to midsummer.
Embryos and larval stages of animals not planktonic as adults have been termed meroplankton. Among the numerically more prominent members of this category are the larvae of bivalve molluscs, gastropods, barnacles and polychaete worms.
Particular attention has been given to impact assessment with regard to meroplankton because this category includes the young of many economically important animals such as clams, mussels ano decapod crustaceans (collectively known as " shellfish"), as well as finfish eggs and larvae (collectively termed "ichthyoplankton").
Details concerning the planktonic distribution of early life stages of clams and mussels (particularly those of the soft-shell clam, Mya are-r naria), and of various finfish tpecies, are contained in Technical l
1 Reports VIII-2 (NAI, 1978a) and VIII-4 (NAI, 1978b), respectively.
A third zooplank on life style category, tychoplankton, consists of organisms which temporarily inhabit the water column when they are swept from the sea bottom by currents or actively migrate up into the water column to feed (often at night). Harpacticoid copepods, nematodes, mysids, amphipods, cumaceans and juvenile decapod crusta-ceans, in part, comprise this group.
This report represents completion of the second annual period (July 1976 through June 1977) of preoperational monitoring of planktonic
3 organisms in coastal New Hampshire waters, and includes the following important study elements:
- 1) analyais and interpretation of spatial and temporal distribution of the more abundant phytoplankters and zooplank-ters; 2) phytop3snkton related factors, including standing crop, primary productivity, and nutrients required for growth and 3) zooplankton biomass.
..,ii
4 2.0 METHODS 2.1 FIELD COLLECTIONS At the three stations shown in Figure 2.1-1, the following samples were taken each month from July 1976 to June 1977:
2.1.1 Net Tows: Meso (Mid-Sized) Zooplankton Two dual-net oblique plankton tows were taken at night, using 333 um mesh nets fitted to a 60 cm "tongo" frame. The tows were 5 to 10 minutes in duration, and were made from the surface to approximately 5 m off the bottom. The volume filtered through each net (approximately 70 to 120 m ) was measured with a General Oceanics digital flow meter.
Upon retrieval, the contents of each net were thoroughly removed by washing, and fixed in buffered 10% formalin.
d 2.1.2 Pumped Samples: Microzooplankton and Net Phytoplankton Four replicate submersible pump samples were taken at night, 2 m below the surface and within 1 m of the bottom.
Each pump discharged on deck into its own small, 76 um mesh plankton net, set into a spec-ially designed stand which filled with seawater to within 15 cm of the top of the net.
Each net was fitted with an 8-dram (33-ml) vial on its cod end. Volume filtered was approximately 100 liters. Contents were thoroughly rinsed from the nets after pumping, and fixed in buffered 5%
formalin.
2.1.3 Water Chemistry Whole water samples were collected with a Kemmerer sampler from 1 m below the surface for chlorophyll a (3600 ml) and nutrient
5 SEABROOK Pt.A'tf C0 ORDINATE 85,000E 90,000E 95,000E 100,000E 7Cf50' g
48
\\
70*46' g
1 J'
\\
l 42*56' -
- 42*56' O
5 i
NAUTICAL MLES 25,000N
/
I 2 KLOMETERS is so so p'
O
'k 30,000N '
e INTA<E SITE T
~
,== CIFFUSER SITE W
jR I
20,000N t
- ,"p
.m--
55'-
p '.#
- 5 5*. -
~
E{_
/
3 25.000N f l
.\\
8 2
-> b c. '.,
g:y j f0 I
,\\
r; l 15,000N s
i g-s* 1 \\ '
i
- 54' 54'-
.E
\\
.{ '
og -
20,000N '
N
~
\\
l
,.:=-
.5
,f' 10,000n
. q
,e e
/
' Nh 'd f'
\\
,i 53' '
g.J f
- 53' 15,000N g' )*
\\
'\\
- f. 5 8
y i
10,000N '
'[
'8 42*52' -
- 42 52' I
\\
\\
i I
\\
71 46' 70*50' 48 85,000E 90,000E 95.000E
\\
Figure 2.1-1.
Plankton sampling stations.
Seabrook Environmental Studies, 1976-1977.
6 analysis (250 ml).
The nutrient samples were bnmediately frozen, while the chlorophyll a samples were irnediately filtered.
At Station 5 only, during daylight hours, water samples were collected from 1 m below the surface with a Kemmerer bottle for primary productivity determinations. Four 250 ml BOD bottles (2 " light" and 2 " dark" bottles) were filled for C uptake estimates and one 400 m1 sample collected for pH analysis. On those dates when water samples were collected concurrently for both chlorophyll a and C uptake deter-minations, the data were used to estimate phytoplankton growth rates using the procedure of Malone (1977).
Concurrent with the collection of water samples, temperature and conductivity measurements were obtained at 2 m intervals with a Beckman salinometer (Model RS5-3). The conductivity readings were later mathematically converted to salinity ( /oo) based on the observed water temperature.
2.2 LABORATORY ANALYSIS 2.2.1 Net Phytoplankton Phytoplankton species from pump samples were enumerated from two independent, one-m1 subsamples in a Sedgewick-Rafter counting cell.
Each subsample was placed under a compound microscope at 100X and three random passes across the width of the Sedgewick-Rafter cell examined.
Net phytoplankton were identified to species as far as practical and enumerated on a cellular basis.
Four replicate samples were analyzed.
2.2.2 Zooplankton Microzooplankton from pump samples were analyzed as follows.
The volume of the vial was concentrated to a known amount based upon the
7.
relative settled volumo of the plankton and detritus. The sample was agitated with a' calibrated bulb pipette in an attempt to homogeneously distribute the contents.
A'l ml aliquot was quickly removed and placed in a Sedgewick-Rafter cell and examined under a compound microscope.
Selected zooplankton taxa (Appendix 7.1) were identified using magnifi-cations of 40X to 200X. Aliquoting and ~ enumeration continued until 300 to 400 organisms had been counted; the entire sample was enumerated when less than 300 organisms were encountered.
Mesozooplankton samples from-333pm mesh net collections were-split using a calibrated Folsom splitter. One half of the sample was used for biomass estimates and the other half was further subsampled for determination of species composition and dbundance.
Biomass was deter-mined by drying in an oven at 40*C for approximately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
For taxonomic analysis, aliquots were quickly removed using a Stempel pipette and examined in a Sedgewick-Rafter cell.
Selected zooplankton taxa (Appendix Table 7.1-3) were enumerated using a compound microscope at magnifications between 40X and 200X. Subsampling proceeded until 300 to 400 organisms (or at least 15% of the subsample) were counted.
2.2.3 Chlorophyll a Water samples (3600 ml) were divided into four 900 ml repli-cates and filtered through a glass fiber filter (.45pm pore size). Near the end of the filtration, 2 ml of saturated MgCO3*
retard sample degradation. Glass fiber filters were frozen pending laboratory extraction of pigment. Extraction of plant pigment consisted of macerating the filter in 90% aqueous acetone and centrifuging.
Chlorophyll a determinations were accomplished using the in vitro fluorometric method (EPA, 1973).
8 2.2.4 Carbon-14 Uptake Samples arriving at the laboratory were inoculated immediately with two microcuries of C as sodium bicarbonate and incubated for four hours at ambient seawater temperature in a flow-through temperature box with 1000-1100 lux fluorescent illumination.
Samples were then fixed with 2 ml of 40% formalin, filtered through a 25 mm Millipore membrane filter (.45 um pore size) at about 15 psi, dried on a planchet in a dessicator and counted using a Nuclear Chicago Model 186 gas flow scin-tillemeter. Primary production was calculated as mg C/m /hr by using the formulae and tables described in Strickland and Parsons (1972).
2.2.5 Plant Nutrients In the laboratory, water samples were analyzed for the fol-lowing series of plant nutrients utilizing a Technicon Autoanalyzer system:
NUTRIENT METHOD REFERENCE (S) total phosphorus persulfate digestion in block diges-EPA (1974) ter, followed by automated colori-metric ascorbic acid reduction orthophosphate automated colorimetric ascorbic acid EPA (1974) reduction nitrite automated cadmium reduction, with-EPA (1974) out cadmium column in place nitrate automatic cadmium reduction EPA (1974) 2.3 OATA ANALYSES Mean values (phy toplankton cells per liter and zooplankton in-dividuals per m ) were computed for all taxa enumerated by sampling
9 location, collection date, and, in the case of pumped samples, also by collection depth.
Replicate abundance estimates for historically repre-sentative species were transformed to log x+
equ va en va ues; 10 logarithmic means and standard deviations were then computed. The log10 (x + 1) transformation presumes a log normal relationship between repli-cate counts and sample collections. Among the more useful attributes of this procedure is reduction of the influence of one or two extremely high replicate values on the apparent overall density distribution.
Density data representing the 10 to 12 most abundant taxa in the phytoplankton, microzooplankton and mesozooplankton assemblages were used to produce three respective graphical displays, the purpose of which was to highlight probable differences in the distribution of these taxa with collection station and/or water depth. The graphical displays were constructed by specifying four mean density categories (combining all collection dates); for example, for zooplankton the categories
<100/m, 100-500/m, 501-5000/m and >5000/m were chosen.
In all three graphical displays, the most dense category was indicated by a com-pletely filled (blackened) box intersecting the taxon (column) and collection site (row) in question.
The least dense category was indi-cated by a completely open (blank) intersecting box (see: Figures 3.1-5, 3.2-7, 3.2-8 and 3.2-9).
10 3.0 RESULTS 3.1 NET PHYTOPLANKTON 3.1.1 Numerical Abundances Total net phytoplankton abundance is given by collection date, station and depth in Table 3.1-1 and Figure 3.1-1.
In general, cell dencities were very low during the study period.
Cell concentrations greater than 2000 per liter were recorded only under the following con-ditions:
- 1) in surface collections at Station 5, on 3 August 1976 and 13 April, 1977; and 2) in all collections made on 9 September 1976 except at Station 5 near bottom. The 9 September collections alone accounted for 48.5% of all the phytoplankton cells counted; August and December 1976 provided the next most abundant collections (Table 3.1-1).
3.1.2 Species Comoosition A total of 107 phytoplankton taxa were identified over the course of the 12 month study. The 35 most prominent taxa are listed in Table 3.1-2.
All taxa identified during the study period are listed systematically in Appendix Table 7.1-1.
Five taxa each comprised more than 5% of the net phytoplankton over all collection dates; collec-tively, these five taxa accounted for approximately 70% of all the cells counted.
The most well-represented of the net phytoplankters were Chaetoceros spp.; in all, 18 Chaetoceros species were identified (Appen-dix Table 7.1-1).
Collectively these 18 species, and the undif feren-tiated (but top-ranked) Chaetoceros spp. category, accounted for approx-This large category represents cells not identified to species because their cellular morphology was substantially altered due to compaction (e.g., on September 9, 1976) when very large quantities were present.
TABLE 3.1-1.
TOTAL NET PilYT0 PLANKTON ABUNDANCE ~(CELLS /LITEp.) MEANS OF FOUR REPLICATES, EACil STATION AND DEPTil. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
1976 1977 J
A S
0 N
D J
F M
A M
J Station 1: Surface 80 1750 5940 492 178 1560 48 266 470 "1
211 120 Bottom 134 1180 6060 335 249 1500 36 136 454 836 114 76 Station 2: Surface 76 843 5560 357 264 1710 52 34 340 471 74 172 Bottom 131 922 3050 128 61 1085 37 67 208 161 2
223 Station 5: Surface 162 2770 7260 508 234 923 34 38 536 2050 95 177 Bottom 89 1240 836 5o5 71 1498 69 36 327 99 12 50 Percentage Representa-tion of Annual Total Count 1.1 14.7 48.5 4.1 1.8 14.8 0.5 1.0 3.9 7.4 0.9 1.4 Bottom = 15 m below the surface 5
12 KEY:
m m
8 8
5
- 8000 -
{
{
{
G G
G SURFACE (Om)
O. o O BOTTOM (-15m) M &
G 7000 -
60n0 -
o e
5000 -
a y 4000-
$d v
3C00 -
o 2000 -
a Ie i
1000 -
8 o
f i
$3 c.
a 4
e f.
L.
- 4. t n:
..e.,
JUL ' AUG I SEP ' OCT I 3
MAR APR MAY JUN Figure 3.1-1.
Total net phytoplankton abundarce; means of four replicates each station ar.d month. _ S,eabrook Environmental Studies, 1976-1977.
TABLE 3.1-2.
ABUNDANCE, RANK, ANNUAL PERCENTAGE COMPOSITION AND FREQUENCY OF OCCURRENCE OF NET PHYT 0-PLANKTERS COLLECTED IN THE VICINITY OF HAMPTON, NEW HAMPSHIRE, JULY 1976 THROUGH JUNE 1977. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
COLLECTION DATES WHEN TAXON RANK COMPOSITION ORGANISM WAS PRESENT Chaetoceros spp.
(see section 3.1.2) 1 26.0 all, except 7 July and 8 February Ceratium tripos 2
16.8 all 12 Skeletonema costatum 3
10.8 except 13 April through 9 June Chaetoceros affinis 4
9.7 7 July, 9 Sept. through 6 Dec., 17 Toril Chaetoceros debilis 5
6.8 all, except 8 February Coscinodiscus spp.
6 4.3 all 12 Nitzschia seriata 7
3.3 3 August through 6 December Rhizosolenia alata 8
2.9 except 3 January through 21 March Chaetoceros decipiens 9
2.8 all, except 3 January and 8 February Ceratium longipes 10 1.7 all, except 8 February Chaetoceros didymus 11 1.4 7 July, 9 Sept. through 6 Dec., 21 March Fragilaria spp.
12 1.1 all, except 9 September Guinardia flaccida 13 1.0 3 August through 7 October, 6 December Thalassiosira rotula 14 0.8 13 March and 21 April, only Chaetoceros brevis 15 0.7 except 3 Aug., 7 Oct., 8 Feb. and 9 Jun Chaetoceros teres 16 0.6 9 September through 6 December, only Chaetoceros laciniosus 17 0.6 7 dates, but mostly fall and winter Detonula confervacea 18 0.5 21 March and 4 May, only Other Pennales 19 0.5 all, except 3 August Cerataulina pelagica 20 0.5 4 dates, but mostly 9 Sept. and 21 March Rhizosolenia delicatula 21 0.5 5 dates, but mostly in fall and 21 March Ceracium bucephalum 22 0.5 7 July through 6 December Nitzschia delicatissima 23 0.4 9 September and 7 October Peridinium depressum 24 0.4 all, except 6 December and 8 February Thalassiosira nordenskioldii 25 0.4 3 dates, but mostly 21 March and 13 April Chaetoceros lorenzianus 26 0.4 6 dates, but mostly 9 September Biddulphia aurita 27 0.4 all 12 Rhizosolenia spp. (other than above) 28 0.4 7 July through 6 December i
F.
W (Coutinued)
m TABLE
',.1 -2.
(Continued)
COLLECTION DATES WilEN TAXON RANK COMPOSITION ORGANISM WAS PRESENT Thalassionema nitzschioides 29 0.4 7 dates, but mostly 21 March Licmophora spp.
30 0.3 7 July through 7 October, 6 December Leptocylindrus minimus 31 0.3 7 July, 9 September, 7 October Navicula crucigera 32 0.2 8 February, only Chaetoceros compressus 33 0.2 4 dates, mostly 21 March Chaetoceros concavicornis 34 0.2 13 April and 9 June, only Melosira moniliformis 35 0.2 except 9 September and 3 January l
l l
l l
l 5
all others, less than 2%
15 imately half of all the phytoplankton cells counted. The category Chaetoceros spp. resulted not from occurrence of some unknown species but was comprised almost entirely of several of the 18 species listed in Appendix Table 7.1-1.
6 3.1.3 Seasonal Differences in Species Composition Cell concentrations are given in Table 3.1-3 for those phyto-plankterr which comprised 10% or more of samples from at least one collection dite.
The prominence of the 9 September collections can be seen from Table 3.1-3 to be due to relatively large concentrations of Chaetoceros spp., particularly those in the top-ranked category which were not differentiated to species. Other taxa which predominated on other dates included: Ceratium tripos, on 3 August; Skeletonema cos-tatum on 6 December; and Chaetoceros debilis, on 13 April. For species considered to be historically representative (see Introduction, Section 1.0) details pertaining to seasonal distribution are shown in Figures 3.1-2 through 3.1-4.
3.1.4 SPATIAL DISTRIBUTION Graphic representation of cell concentrations for ten of the more abundant phytoplankton taxa is given in Figure 3.1-5 by station and depth. Distributional patterns exhibited in this figure appear to be complex, suggesting no clearly definable trends encompassing more than one species.
In general, when cell densities were expressed logarith-mically (Figures 3.1-2 through 3.1-4) there appeared to be few dates on which there were clear-cut concentration differences with station or depth. Notable exceptions include:
- 1) Chaetoceros debilis (Figure 3.1-
- 3), higher cell concentrations near the surface at Station 5, on 13 April 1977; and 2) Ceratium long1 pes (Figure 3.1-4), higher cell con-centrations near the surface at Stations 2 and 5, on 4 !;ay and 9 June 1977.
TABLE 3.1-3.
NUMERICAL ABUNDANCE (CELLS / LITER) 0F NET PHYTOPLANKTON DOMINANTS (COMPRISING 10% OR MORE OF TOTAL CELL COUNT, ON ONE OR MORE COLLECTION DATES), AVER /GED OVER ALL STATIONS AND DEPTHS.
SEABROOK ENVIRONMENTAL STUDIES, 1976-1977.
COLLECTION DATE 7
3 9
7 9
6 3
8 21 13 4
9 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN TAXON 1976 1976 1976 1976 1976 1976 1977 1977 1977 1977 1977 1977 Chaetoceros spp.
( see Section 3.1.2) 0 6 2320 33
<1 27
<1 0
12 33
<1 1
Ceracium tripos 63 1300 156 17 6
9 14 1
<1 sl
<1
<1 Skeletonema costatum 2
1 104 233 4 1050 1
2 4
0 0
0 Chaetoceros affinis 1
0 893 1
2 18 0
0 0
<1 0
0 Chaetoceros debilis 1
0 64
<1 5
124 1
2 24 450
<1 11 Coscinodiscus spp.
<1
<1 23 5
117 155 21 45 37 39 1
3 Nitzschia seriata 0
1 257 49
<1
<1 0
0 0
0 0
0 Chaetoceros decipiens 0
0 132
<1 1
16 5
6 41 47 4
14 Ceracium longipes 15 49 26 1
<1
<1 1
0 1
<1 20 43 Fragilaria spp.
6 1
0 5
6 7
0 6
1 6
18 36 Thalassiosira retula 0
0 0
0 0
0 0
0 68 11 0
0 Detonula confervacea 0
0 0
0 0
0 0
0 50 0
1 0
Peridinium depressum 2
<1 10
<1
<1 0
<1 0
<1
<1 21 5
Navicula crucigera 0
0 0
0 0
0 0
19 0
0 0
0 Melosira nummuloides 1
0 0
0 0
2 0
0 1
<1 11 0
5 1
17 4-KEY:
SURFACE BOTTOM ---
3-(
I \\
I \\
/\\
/
\\
2_
, s
/
\\
\\
/
g
\\
/
g g
\\
\\
\\
\\
1-
\\
\\
~
/
g
- \\</
I,,
y' N
g
/
g:
N
- a. STATION 1 5
-U a:
8' 3-v y
T U
j.
5 2-i o
~~2 M.
\\
f 7
s
/
x
/
I 1-f S.
l
\\. l 8
/
p
/
\\
~ ' '
'N
- b. STATION 2 f
g
/
\\ X'.'
N Y
3-b(
\\
3 I
\\
2-
\\
l
\\
\\
/
\\
/
\\
/
\\
/
\\
lj
\\
/
\\
/
\\
\\
1-
/
\\
f g
/
\\
/
g f
1'
/
Numerical abundance of Skeletonema costatwn, means of four replicates. Standard deviations shown except where less than
.10.
Seabrook Environmental Studies, 1976-1977.
18 I
4-KEY:
SURFACE BOTTOM -
3-
- a. STATION 1
/
/
\\
is 6
/\\
2-h\\
\\
/
g
//
\\
/-
f" \\
,/.'. \\
/'
g
\\
\\
,I
~'
)
\\
J x
\\
1
\\
/
/
g f
t "fl
\\
/
\\
l
\\
1-l l
/
b
}\\
i
/
/
\\
/
t.
&j
.,, /
E W
U 3-5b
~
- b. STATION 2 2-
[
/
4\\
/.
).
5 y
\\
s
'-Q l
w Q
'/
\\
i t
1-
- l/
l
\\
\\
i
+
g
/
}
,/
f s'
D
//
8
/
a z5 x
3-
- c. STATION 5 2-
~
l\\
l /\\
/ \\
/
,/
\\
f' T
\\
1-
\\
t
/-
\\
/
k
/
/
\\
l
\\\\f-
\\
'/
s t/
t
, y JUL A*JG ' SEP OCT ' NOV ' DEC ' JAN FEB ' MAR ' APR ' MAY JUN Figure 3.1-3.
Nunerical abundance of chetoceros debilis, means of four replicates. Standard deviations shown except where less than
.10.
Seabrook Env.ironmental Studies, 1976 - 1977.
19 I-4_
KEY:
SURFACE 3-BOTTOM ---
2-
- 4. STATION 1 7--==:.d i
\\
/ [--__ __
1_
'N
\\
/
/
\\
/
\\-
D-I,#
/\\/
5C a
5 3-S
~
- b. STATION 2 Q
2-
.< ~
O
~
/ N, y.
+
~
/
5 1-
?
\\
/
/
N.,
/
e q
o
'. )
- -[ -
__ MK
/
w 3-
- c. STATION 5 2-
/
\\
\\
\\
1-
\\
,'g
\\
\\~-
,/
g
___p JUL ' AUG ' SEP OCT ' NOV ' DEC I I
I I
' MAY '
I JAN FEB MAR APR JUN Figure 3.1-4.
Numerical abundance of Ceratitan longipes, means of four replicates.
Standard deviations shown except where less than.10.
Seabrook Environmental Studies, 1976-1977.
1
_/
20
/
h ///tt/h kt////H H I
STA 1 SURFACE V/#4ll1111111 111111111 7/ # / #/#4V/#/#/#/2 STA 1 BOTTOM mmilllilill e Illlllill lilllill W/##//EW#4 STA 2 SURFACE 11llllll lilllilllV#/EV#EV/##/#/4W#4V/#/
STA 2 BOTTOM llllllllllll11ll11V/#47#/4W/A
'/EMV#/4 STA 5 SURFACE MV/////
V//E llllilll lllilllll W#4V#E STA 5 BOTTOM
/ # # 4 1llllll17## /#/z
//#A//#//s F/#4 KEYI i <10/ Liter 7#4 10-49/ Liter 111ll11 50-99/ Liter
>100/ Liter Figure 3.1-5.
Mean densities by station and depth of 10 taxonomic compo-nents of net phytoplankton assemblages in the vicinity of Hampton Beach, flew !lampshire.
Seabrook Environmental Studies, 1976 - 1977.
~
)
21 3.2.5 Chlorophyll c Means and standard deviations of chlcrophyll a measurements are presented in Figure 3.1-6 and in Appendix Table 7.1-2.
In general, the seasonal pattern of chlorophyll a concentration closely resembled that of total net phytoplankton cell concentration (cf. Figures 3.1-1 and 3.1-6).
Similarities included the occurrence of:
- 1) maximum con-centrations on 9 September, 2) relatively modest spring values, and 3) very low concentrations in January and February. A dissimilarity was that the relative cell concentration peak on 6 December 1976, was not reflected in the chlorophyll a concentration data.
This may be explained in part by the fact that the principal species involved, Skeletoneca costatu.m, has very small cells.
3.2.6 Primary Productivity Table 3.1-4 presents estimates of Carbon 14 uptake rate at Station 5, and relates these to concurrent values of chlorophyll a concentration.
Highest carbon uptake rates were obtained fo'. 9 June 1977, followed by rates obtained for 7 September 1976, and 14 April 1977. Very low uptake estimates were obtained on 8 July 1976 and 4 January and 7 February 1977. Highest ratio of carbon uptake to chlor-ophyll a concentration (5.0 C/Chl a per hour) was recorded for 4 May 1977, followed by the ratio for 9 June 1977 (4.0 C/ Chi a per hour).
Assuming an internal carbon to chlorophyll a ratio of 30 for phyto-plankton cells in general (Malone, 1977), estimates of the time required for populations to double their numbers ranged from as briefly as approximately 10.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, on 4 May 1977, to 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> on 5 October and 6 December 1976 and 21 March 1977 (Table 3.1-4).
3.2.7 Plant Nutrients Table 3.1-5 presents concentration data for forms of nitrogen and phosphorus which promote phytoplankton growth.
Nitrate concentra-
____ a
22' 6-
-5 2..
5-4-
m 5
g 4
s 3-5 l
t 5
1 I
2-2 5
l t +5 t
+
3 2
5 2
Y
~
"2 1
5
+i "
l 1_
2 5 t--
t t
125 i
3 2.
i
++..
5
+ 4 +5 Y 5 +2 5 t ty JUL ' AUG ' SEP
'OCT NOV ' DEC JAN~' FEB MAR APR ' MAY ' JUN l-l.
[
Figure 3.1-6.
Chlorophyll a concentration (means and standard deviations) at Stations 1, 2 and 5.
Seabrook Environmental Studies, 1976 - 1977.
TABLE 3.1-4.
PRIMARY PRODUCTIVITY, RATIO 0F PRODUCTIVITY TO BIOMASS AND CARBON SPECIFIC PHYTOPLANKTON GROWTH RATES AT STATION 5.
SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
PRIMARY PRODUCTIVITY RATIO 0F (mgC/m /hr)
BIOMASS:
PRODUCTIVITY CARBON SPECIFIC 3
INITY REPLICATE REPLICATE CHLOROPHYLL a TO BIOMASS GROWTH RATE TEMPERATURE sag /oo)
(
1 2
-(mg/m )
(C/CHL/HR)
(D0UBLINGS/ DAY")
DATE
( C) 3 8 Jul 76 15.9 31.0-31.5 0.46 0.59
--- b 5 Aug 76 16.1 31.1-31.6 2.26 1.78
--- b 7 Sep 76 10.6 30.8-32.2 3.65 4.65 2.1 0.5 1.98 1.4 5 Oct 76 12.9 32.5-32.8 2.20 2.80 2.5
.1 1.00 0.8 8 Nov 76 9.0 32.7-33.2 2.31 1.98 1.51.3 1.43 1.1 6 Dec 76 6.2 31.6-31.9 0.66 0.82 0.8
.2 0.92 0.8 4 Jan 77 3.0 33.5-33.7 0.58 0.57 0.4
.1 1.44 1.1 7 Feb 77 0.5 34.0-34.4 0.50 0.2
.02 2.50 1.6 21 Mar 77 1.9 32.2-32.4 2.29 2.27 2.5 1.0 0.91 0.8 14 Apr 77 4.4 30.7 4.11 3.80 1.91.05 2.08 1.4 4 May 77 9.2 29.9-30.9 2.36 2.59 0.51.2 4.95 2.3 9 Jun 77 9.2 30.7-31.6 5.68 5.47 1.4
.2 3.98 2.1
" Calculated using the expression 3.32 log (30 + C:Chl)/30; 30:1 is assumed to be the ratio of carbon tochlorophyllainanormalphytoplanktoncell (Malone, 1977).
M b Chlorophyll a samples not collected concurrently with primary productivity (See Appendix Table 7.1-2)
24 TABLE 3.1-5.
PLANT NUTRIENT CONCENTRATIONS BY. STATION AND SAhPLING DATE.
SEABROOK ENVIRONMENTAL STUDIES,1976-1977.
I z
TOTAL S
ORTH 0PH0SPHATE PH0SPHORUS NITRATE NITRITE AMMONIA Q
P0 -P TOTAL P NO -N NO -N NH -N 3
2 3
M (qgfl)
(ug/1)
(ug/l)
(ug/1)
(ug/1)
July 7
1 30 66 5
2 39 2
12 27
<l 1
NA 3
6 20
<l 1
NA 4
7 21
<1
<l NA 5
10 25
<1 1
NA August 3
1 9
24
<1 1
<10 2
2 27
<1 1
<10 5
2 21
<1 1
<10 September 9
1 13 35 5
2 239 2
9 33
<1 1
NA 5
10 35
<1 1
16 October 7
1 11 43 10 5
14 2
9 51 5
4 16 5
7 51 2
3 10 l
November 9
1 28 52 108 2
NA 2
17 40 66 2
NA 5
22 40 92 3
NA December 6
1 2
34 55 6
NA 2
12 35 62 4
NA 5
8 32 34 3
NA January 3
1 20 29 8
<1 NA 2
23 42 5
<1 NA 5
38 53 6
<1 NA (Continued)
25 TABLE 3.1-5.-
(Continued) z TOTAL 2
ORTH 0 PHOSPHATE PH0SPHORUS NITRATE NITRITE AMMONIA Q
P0 -P TOTAL P NO 3-N N02 -N NH -N 3
(49/l)
(u9/l)
(u9/l)
(u9/l).
(ug/l)
February 8
1 21 44 21 16 NA 2
17 38 12
<1 NA-l 5
18 30 17
<1 NA March 21 1
15 20 11 3
NA 2
12 19 8
2 NA 5
19 24 12 4
NA
- l April 13 1
14 20 8
3 NA 2
18 21 8
3 NA 1
5 18 26 10 4
NA May 4
1 13 16 1-
<1 NA 2
15 16 2
<1 NA 5
10 16 1
<1 NA June 9
1 12 11 13 2
NA 2
7 10 8
1 NA 5
8 13 6
1 NA 4
NA = Water sample not analyzed for ammonia t.
26 tion values exceeded 15 pg/l only during late fall and winter (November through February) with peak values recorded for 9 November 1976. During the summer months, values were usually below detectable limits. Nitrite concentrations exceeded 5 pg/l only at Station 1, on 6 December 1976 and 8 February 1977.
Analyses for ammonia were not routinely carried out until July 1977.
Lowest total phosphorus concentrations were recorded for 9 June 1977, coinciding with highest primary productivity levels observed (see Section 3.2.6).
The highest total phosphorus levels (66 pg/1) were recorded for Station 1, on 7 July 1976.
In general, however, total phosphorus concentrations tended to be higher by a factor of 2 or 3 during the fall and winter months than during the summer or spring months. Ortnophosphate (the most rapidly assimilable form of phos-phorus) followed a similar seasonal pattern although differences between warmer and colder months were not as pronounced as in the case of total phosphorus. With one exception, orthophosphate values were 15 pg/l or less from 7 July through 7 October 1976 and on 4 May and 9 June 1977.
The one exception was an orthophosphate concentration value of 30 pg/l recorded for Station 1 on 7 July 1976.
Often, concentrations of most of the nutrients investigated were higher at Station 1 than at either Station 2 or Station 5 (Table 3.1-5), suggesting contributions from anthro-pogenic sources (e.g., sewage effluent, septic tank leachate, etc.).
l 3.2 200 PLANK_N_
l 3.2.1 Species Composition l
I Approximately 73 zooplankton taxa were designated and enumer-ated during the 12 month study period frcm July 1976 through June 1977, 1
l The 27 most prominent taxa are shown in Table 3.2-1.
All taxa are listed systematically in Appendix Table 7.1-3.
Overall, the numerically most important taxa included:
copepod nauplii, Olthona spp., Pseudo-calanus spp., bivalve veligers, Eurytemora spp. and Centropages spp.
l
?
l
TABLE 3.2-1.
ABUNDANCE, RANK, ANNUAL PERCENTAGE COMPOSITION AND FREQUENCY OF OCCURRENCE OF ZOOPLANKTERS COLLECTED IN THE VICINITY OF HAMPTON, NEW HAMPSHIRE, JULY 1976 THROUGH JUNE 1977.
SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
COLLECTION DATES WHEN TAXON RANK COMPOSITION ORGANISM UAS PRESENT Copepod nauplii (predominantly Ca) 1 34.6 all 12 Oithona spp. (Cy) 2 29,8 all 12 Pseudocalanus spp. (Ca)*
3 10.8 all 12 Bivalve veligers 4
7.6 all 12 Eurgtemora spp. (Ca) 5 3.1 all, except 3 Jan Centropages spp. (Ca) 6 2.4 all, except 4 May Gastropod veligers 7
1.9 all 12 Cirripedia (Barnacle) larvae 8
1.5 except 6 Dec through 8 Feb Nicrosetella norvegica (H) 9 1.4 all 12 Acartia spp. (Ca) 10 1.1 all 12 Polychaete nectochaete larvae 11 1.0 all 12 Temora longicornis (Ca) 12 0.7 all 12 Bryozoan cyphonautes larvae 13 0.7 7 July through 6 Dec Calanus finmarchicus (Ca) 14 0.5 all 12 Harpacticoida 15 0.5 all 1.2 Polychaete eggs 16 0.4 6 (principally Spring and Fall)
Paracalanus parvus (Ca) 17 0.3 except 8 Feb through 9 Jun Gastropod eggs 18 0.2 except.6 Dec and 3 Jan Necridia spp. (Ca) 19 0.2 all 12 Evadne spp. (C1) 20 0.2 except 9 Nov through 8 Feb Podon spp. (Cl) 21 0.2 except 6 Dec through 13 Apr Echinoderm larvae 22 0.2 6 (principally Spring and Fall)
Nematodes 23 0.1 all 12 Tortanus discaudatus (Ca) 24 0.1 all 12 Rotifera 25 0.1 6 (principally in Spring)
Paracalanus crassirostris (Ca) 26 0.1 9 Nov through 3 Jan Brachyuran (Crab) larvae 27 0.1 except 9 Nov through 13 Apr
~
- All others less than 0.1%
- includes individuals identified as P. minutus and Pseudocalanus " Type A" ww.
Holoplankton Codes: Ca = Calanoid copepod C1 = Cladoceran Cy = Cyclopold copepod H = Pelagic harpacticoid copepod
28 Together these six taxonomic catogories comprised approximately 88% of the total number.of organisms enumerated. The Copepoda accounted for approximately 85% of the total number of organisms.
3.2.2 Seasonal Distribution 3.2.2.1 General Results of the two collection methods (76 pm pump samples and 333 um net tows) are presented in terms of mean total zooplankton den-4 sity (per m ) by collection date in Figure 3.2-1 and Appendix Table 7.1-4.
Animals collected by pumping seawater into a 76 um mesh net far outnumbered larger. forms captured by the 333 um mesh bongo net.
$nor-mous numbers of horse mussel (Modiolus modiolus) straight-hinge veligers (less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> old) were enumerated from the 7 October 1976 pump samples. For reasons explained in nore detail in the discussion (Sec-tion 4.0), it was considered appropriate to regard the occurrence of these early veligers as a chance ancmaly when considering overall pat-terns of seasonal abundance of total zooplankton.
Discounting the straight-hinge M. modiolus, both microzoopiankton and mesozooplankton 4
3 collections exhibited peak densities on 9 June 1977 (44,100/m and 3660/m, respectively).
Second highest levels of abundance (30,400/m for microzooplankton; 1280/m for mesozooplankton) were also recorded for the same date (7 July 1976). The highest late summer / fall densities occurred on 9 September 1976, for the microzooplankton (28,600/m ) and on 9 Noverber 1976, for the mesozooplankton (ll60/m ).
Of the three categories based on zooplankton life style, holoplankters contributed by far the greatest percentage to total num-bers collected and tychoplankters the smallest percentage (Figure 3.2-2).
Mean abundances by life style category are shown for each collec-tion date in Appendix Table 7.1-4b.
Highest densities of holoplankters were recorded on 7 July, 3 August and 9 September 1976, and 9 June 1977,
29 ghthin 1
vae KEY:
73-m k
SONGO NET TOWS (333pm mesh)
N 40,000 -
N 30,000 -
"r 20,000 -
10,000 -
N h
h
' AUG ' SEP OCT NOV ' CEC ' JAN FEB ' MAR 3 I
i JUL APR MAY JUN S abr ok n ro, men a Studie, 9 6-977
l 30 TYCH0 PLANKTON MER0 PLANKTON HOLOPLANKTON 100 -
p 90 -
80 -
i 70 -
I 60-Et:
50 -
8
==
40 -
30 -
20 -
10 -
N O
3 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR ' MAY JUN A
- a. excluding straight hinge veligers of N. modiolus
~
- b. including straight hinge veligers of M. modiotus Figure 3.2-2.
Percentage contribution to total abundance by holoplanktonic, meroplanktonic and tychoplanktonic forms for each collection date.
S ~ brook Environmental Studies, 1976-1977.
r 31' i
4 -
each collection exceeding a mean density of 20,000/m. Highest den-l sities of meroplankters occurred on 7 July, 9 September and 7 october, 3
1976, each collection exceeding a mean density of 6000/m. Tychoplank-ton mean densities exceeded 200/m in collections from 7 July 1976 and 4 I
May and 9 June 1977.
3.2.2.2 Holoplankton l
Aost of the holoplankters listed in Table 3.2-1 were repre-t i
sented throughout the study period or were absent only during some of the colder months. A few exceptions were Centropages spp., which were absent in spring and Paracalanus parvus, which was not present in j
collections after 8 February 1977.
Copepod nauplii were most abundant on 9 September 1976 3
(12,300/m ),
and 9 Jr.ne 1977 (21,940/m ) (Appendix Table 7.1-4c).
Lowest densities were recorded for 3 January and 8 February 1977 (1980 3
and 1930/m, respectively). These nauplii represent the earliest post embryonic life stages of calanoid (Ca) copepod species listed in Table 3.2-1.
Seasonal abundances of the next major developmental stage, the copepodite stage, are represented in Figure 3.2-3 for the six principal calanoid species present. Further detail regarding seasonal distribu-tion characteristics can be seen in Figures 3.2-4 and 3.2-5 for cope-t f
podites and adult males and females of the two most abundant calanoid species, Pseudocalanus minutus and Eurytemora herdmani.
l With the exception of copepod nauplii, cyclopoid copepods of Oithona spp. were the most abundant of all taxa.
Although it was possible to distinguish Olthona spp. from any other copepod genus at all life stages, only adult females could be unequivocally identified as belonging to one of two congenerie species, O. simills or O. plumifera.
On the basis of the ratio observed among the adult females, O. simills was about 20 times as abundent in the collections.as O. plumifera.
Distributional characteristics of Olthona spp. nauplii, copepodites,
32 4-3-
l'*** fi"~akhina 1
g_
..\\
/'I
- ~
N I
1 3-re-om longisor~~ie 2-
\\>
./N I~
N x
~r_
5
~.J Acartia spp.
M
~
2-T b
[1 v
N
/
c 1-m Q
2 3-Centmpagea spp.
p y
~
2-o e"'
o 1-NT E
3-Da':! e on spo.
t
/
{-
1 T
~w 3-Sm/
g 2-Pseudocatar.ua.-inutus 1-JUL AUG ' SEP ' OCT '
I NOV OEC JAN FEB ' MAR APR MAY ' JUN I
3 Figure 3.2-3.
Seasonal abundance of copepodites representing six species i
of calanoid copepods.
Seabrook Envirormental Studies, 1976-1977.
l
~~.
33 STATION 1*
STATION 2 ---
STaTr '. si 3-f
/
/
,s
/ \\
is
/
'/
\\
s s
/
/:./.s g
N
/
\\
z.......*
/
s
/
\\
.N
........,.s t
2-s
/
s f
.s N/
\\
.s s/
s,
./
. s.s.s
- f
\\/
.s s
1-
- a. FEMALES n
mz a:
w 3-c.
3
/
H A
's
/.....e.-
/.\\
m
/.
s
/
z 2-
- s
/
s W
/:
., s,/ s *".......... * * *,.. * * * *.
\\
,6 *,.'
O ys 0
/
/\\
g m
\\
/
\\
/.
- ., N
/
g f
/
g f :.
. N
/r
\\
/:
+
\\
S
/ :..
s
. \\'m/::
x
\\
- s. ::
f 1-
\\
/ :l s
o
\\
/
=........:
ca
/.:
~
\\
o
\\
\\
t.
a y ;/
l v
- b. MALES z<W 5
g 5
2 5
5 1 5 i
yT
/
5
/.
2 ll
/
N 2
/
4-
. 's 2'
5,,,y/.
K.w,.,
,. 7 2,
.... -,i s
,r.........,**.**=.2 5
~~.,_
2
?*
17,s.
2'
..... s u ss se 3-h
~.
- q. n o N
, %/
2-i I,
1-
Figure 3.2-4.
Mean abundance of PseudocaZanus minutus life stages by station.
Standard deviations shown except where less than.25.
Seabrook Environmental Studies, 1976-1977.
__m 34 4-KEY:
3-STATION 1 """
STATIGN 2 ---
STATION 5
/ *..,, *
- 5 2-
- h
- I s s
\\
ei N
/
s
./ 8 s
g y..........
... - l
\\
1--
\\
2
.f I
1 2
i
/
f v
m y
=
f om 2
.,7s E
- *..?.s
.sh,,,' ps \\-
f
- a. FEMALES M
t W
Q
~ -
- i
.b--
3-m ZW
. r, lI \\
- mq 2-l,1.. \\
.f,I b~
~
s
\\
"2 O
,1,
//
-s i,
s
.,..... ; g s
1 c.s s
\\
e 1
o s,**.=..
e e
/
g_
s J
s f
<s 2
/
/
.c
.,5-s,..
5 z
s 2r I
w s.
3 s
'.h__,,.-
's b* MALES
~
N
._n_
4-
\\
,./
.' S l
is s/
3-e s.
/
,s
/
I i
2
/
'./
2-2, i
2
/
1 t"
2 i
/
3
' / 2,s /
i
/,
2 i_
~~.,
.,,,...... -.-5 /
/:'s,
',.s
/1'I3
,T 'N 2 e
s N*
., /
- \\r N
s s
/
P ju,...
s
- N \\
p'
- c. COPEP0 DITES s.
ni s
APR ' MAY ' JUN JUL ' AUG ' SEP OCT NOV DEC JAN FEB ' MAR '
Figure 3.2-5.
Mean abundance of Eurytemora hardnani life stages by station.
Standard deviations shown except where less than.25.
Seabrook Environmental Studies, 1976-1977.
4 t
-e-
- - - - -- w w w -,
,ww
.,yv re
-v,..
,,--v
---.---r,v,v-
+--m.
e
,-w,--r,.
-re-,v.--<
- --y
r-
=
35 males and females are given in Figure 3.2-6.
A similar pattern of gradual decline in abundance, from summer 1976 to spring 1977, followed by a relatively rapid increase by late spring, appeared to apply to all four life stages.
3.2.2.3 Meroplankton Invertebrate taxa at the suborder level or above which were generally well-represented in the meroplankton are listed in Table 3.2-2.
Collecti ely these eight groups comprised approximately 14% of the total zooplankton collected (76% if the 7 October 1976 count of M.
modiolus straight-hinge larvae were included), and all but a fraction of a percent of the meroplankton. Bivalve veligers, the most ibundant meroplankton component, exhibited densities in excess of 1500/m on 7 July, 9 September, 7 October and 9 November 1976.
Overall, bivalve larvae densities were much higher in the last half of 1976 than in the first half of 1977 (Table 3.2-2).
Gastropod embryonic and larval forms exhibited a similar trend. The highest density of polychaete embryos and larvae was recorded for 9 September 1976 (1310/m ); an apparent secondary peak (668/m ) occurred on 4 May 1977.
Cirripedes (i.e.,
barnacles) were most abundant in early spring, with the apparent peak (2390/m ) occurring with the 4 May 1977 collection.
Bryozoan larvae were present only in the 1976 collections, with peak density values recorded for 9 September and 7 October. Both decapod and echinoderm larvae exhibited seasonal patterns of abundance, with the former group appearing to favor the summer months, and the latter group exhibiting bimodality centering on the September-October 1976, and April-May 1977 collections.
Isopoda (epicaridean larvae) occurred sporadically in the collections, with the apparent peak density recorded for 7 July 1976.
36 5-4-
s 3-T 1
,N 3
N' N
2-
.N 1-
- a. FEMALES
^
mr a
4-i.a Q.
3-
'g~
2-E s-- - - - -
/N_-
o 1-N
- b. MALES
+x v
i o
4-I
.~C 7
z K
5 N-
/
f 2-x i
l 1-
- c. COPEP0 DITES g _.
l.
N
[.
3-
\\-
2-
.. \\/
l L
1-
- d. NAUPLII i
JUL AUG SEP ' OCT NOV DEC ' JAN ' FEB I MAR ' APR MAY JUN I
8 I
l l
t i
1.
Figure 3.2-6.
Seasonal abundance of four life stages of Oicho. a spp.
n Seabrook Environmental Studies, 1976-1977.
4 3
TABLE 3.2-2.
MEAN ABUNDANCE (PER M ) 0F IMPORTANT INVERTEBRATE TAXONOMIC GROUPS IN THE MER0 PLANKTON, l
BY COLLECTION DATE.
SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
GROUPS
/ / / i l /t COLLECTION DATE U
8 e
o w
q N
7 July 1976 5,650 1,110 108 65 15 68 0
20 3 August 1976 328 957 129 16 4
89 0
1 9 September 1976 2,680 1,270 1,310 32 796 16 119 1
7 October 1976 5,020 374 287 4
637 1
115 6
b556,000
)
9 November 1976 1,800 97 13 3
42 2
0 1
j 6 December 1976 165 38 16 4
9 0
2 1
i 3 January.1977 147 7
1 0
0 1
0 1
8 February 1977 128 8
4 0
0 1
0 3
21 March 1977 9
39 144 568 0
1 5
1 13 April 1977 139 103 157 100 0
0 40' 0
4 May 1977 77 128 668 2,390 0
2 44 0
9 June 1977 354 458 223 40 0
73 0
3 Percentage repre-i sentation of total meroplankton, on an annual basis 43.2" 21.9 13.1 14.4 3.0 1.2 1.2 1.5 94.9
" excluding straight hinge veligers of M. modiolus including straight hinge veligers of M. modiolus
38 3.2.3 Spatial Distribution Graphic representations of taxonomic mean density spatial distributions (all collection dates combined) are shown in Figures 3.2-7 through 3.2-9.
Several of the taxa listed appeared to exhibit a distri-butional pattern consisting of an affinity for surface waters in the open coastal area (Stations 2 and 5) and dispersal (i.e., no depth affinity) within Hampton Harbor (Station 1). This distributional pat-tern was best exemplified by bivalve veligers and barnacle larvae (Fig-ure 3.2-8), and by Olthona spp. copepodites and nauplii (Figure 3.2'9).
Adult Olthona spp. appeared to be associated more strongly with surface waters whatever the station location (Fi,gure 3.2-9).
Acartia hudsonica
(= A. clausi) and Eurytemora herdmani exhibited evidence of'an affinity for harbor waterst Pseudocalanus minutus, Calanus finmarchicus cope-podites, Centropages typicus, Metridia spp. copepodites, Podon spp.,
Temora longicornis and Tortanus discaudatus exhibited affinities for open coastal waters (Figures 3.2-7 and 3.2-8).
Figures 3.2-7 and 3.2-8 suggest that inshore / offshore distribution trends tended to be more demonstrable for sexually mature than for sexually immature individuals.
l Gastropod veligers and the pelagic harpacticoid, Microsetella 1
norvegica, appeared to be well dispersed throughout the study area (i.e., no depth or station affinities indicated).
Polychaete larvae appeared to be concentrated in the surface waters of Hampton Harbor.
The only taxon exhibiting indication of bottom water affinities was Temora longicornis copepodites (Figure 3.2-8).
3.2.4 Biomass l
Results of mesozooplankton biomass measurements from oblique bongo net tow collections are presented in Figure 3.2-10a, and Appendix I
Table 7.1-5.
Seasonal and spatial distribution trends appear similar to trends exhibited by the numerical abundance data (Figure 3.2-10b) with a few notable exceptions. These exceptions relate to the difficulty of I
39
/>
o a/ r &o r;t);e/
is/
p e
e r
s* r / / r r P.
,e j j /W///e/
STATION 1 "Illill W/#Willllill #####4 1llllll1i
&#f STATION 2 lilllilllW#,IllilllllW#/ IlllllillW/AWMM/#j y/#2 STATION 5
'<//Allllllill,llilillllllilllllif##ppp,pilillllly#fp////,
Figure 3.2-7.
Mean densities by station of 11 ~zooplonkters in bongo net tows from the vicinity of Hampton Beach, New Hampshire.
Data represent sexually mature adults except where other-wise indicated.
Seabrook Environmental Studies, 1976 - 1977.
o g
/,
-is 1 r. i s/ / "r / s / a
/
/ / // //"// /
ej /
r u
STATION
/
1 SURFACE m tilllilllllllilllV#####ZWM###/M# 11111111 l
l 1 BOTTCM M ///M\\liIIIIIlVWMW#/########//AWH/
2 SURFACE 11111lll ##AlilillllV##MW##/##/
2 BOTTOM 1111lll1llllllll!!I11111113 5////###4
'/##f##/
7/#//
5 SURFACE 1111111 ##$11111111 #####/ ## ##WM/
5 BOTTOM 111lllltlllllll1lllllll1lllllllIlllV##/lillllllW#A
'/##>
7##/
i i
I I
i I
i i
3 KEY:
< 100/m a.
nauplii, copepodites and adults l
'//# 100-P"m b.
copepodites only l
1111ll11 501-St 0M
>5000 m l
Figure 3.2-8.
Mean censities by station and depth of 12 taxonomic components of pump zooplankton assemblages in the vicinity of Hampton Beach, New Hampshire.
Seabrook Environmental Studies, 1976 -
1977.
i 40 8
e c
a b
g 4 s 4
STA 1 SURFACE lilllillV#// 111111ll l11111111 STA 1 BOTT0M V//#4 Y///##//A STA 2 SURFACE lillllll V # # /x M
STA 2 BOTTOM 7/#/4 lll1llll !!!llll111 1111lllll' # //
STA 5 SURFACE i
STA 5 BOTTOM 7##4 ll111111,111111111 i
3 KEY:
< 100 /m 3
'//#, 100-500 /m 3
11111111 501-5000 /m 3
M >5000 /m l
l l
l l
l l
Figure 3.2-9.
Mean density, by station and depch, of various life stages of Oithonc spp.
Seabrook Environmental Studies, 1976 - 1977.
l l
41 3
120-
- a. BIOMASS (numerals indicate station nuriber) 5 100 -
5 j
80 --
2 m
2 4 60 -
E f5
~
25 5
5 40 -
5 1,
2 5
2 2'
2 2 5 20 -
f 2
., 5 Y
h*
2 5 3
14 6 f
f i
0 JUL ' AUG ' SEP ' OCT ' NOV DEC ' JAN FEB ' MAR APR ' MAY JUN '
j 5000 -
- b. NUMERICAL ABUNDANCE l
STATION 1
[
]
STATION 2 ---
I STATION 5 4000 -^
f I
I l
I I
I I
)
"r 2000 -
l x
j e
/
Q I
I I
= 2000 -
I I
. (..........
- l-
- I 1000 - __,_,_N
/
/
'.&.... g..,.. ss,
l j
1; 0
JUL AUG SEP OCT NOV ' 0EC JAN ' FEB ' MAR APR ' MAY ' JUN
\\
l-l l
Figure 3.2-10.
Means and standard deviations of mesozooplankton biomass (mg/m3 dry weight), and mean numerical abundance (per m )
3 by station and collection date for bongo net tows.
Seabrook Environmental Studies, 1976 - 1977.
l l
r I
t 42 f'
accounting for the moderately high biomass values shown'for Stations 2 and 5 on 9 November,1976, and 21 11 arch 1977.
Numerical abundances (Figure 3.2-10b) recorded for those same dates were not of comparable-i l
value, particularly on 21 March 1977.
The most plausible explanation is that, on those dates, the bongo nets captured substantial masses of organisms not enumerated for the purposes of this particular study.
Cursory re-examination of the collections indicated that these organisms were various life stages of mysids (opposum shrimps), euphausiids (krill) and, to a lesser extent, cumaceans.
I I
i i
[
i t
l l
I l
l l
1 i
4 0
.,..,~,.~-,,4
~..r,
,m.......;._,
-,_,,,w,,_.,,__,,.,,,.
.~,,,m.__
im. - ~, - -
43 4.0 DISCUSSION 4.1 PHYTOPLANKTON 4.'.1 General During the present study period (July 1976 through Cune 1977),
total net phytoplankton cell densities were usually found to be less than 2000/ liter, even during the spring (Table 3.1-1).
Such values appear remarkably low with respect to observations from previous studies (NAI, 1973; 1974; 1975; 1977a) which recorded cell concentrations in excess of 10 / liter during spring blooms.
The implication is that the 1976-1977 period was one of relatively sparse phytoplankton density.
This supposition is supported by the historical record of chlorophyll a measurements (Table 4.1-1) which shows that chlorophyll a concentration values for collection dates from October 1976 through May 1977 esta-blished new monthly low records.
Over that same period of time, how-ever, primary productivity (as measured by Carbon 14 uptake) was not substantially lower than on comparable sampling dates one year earlier (Table 4.1-2).
Historical records of nutrient availability (Table 4.1-3) indicate much lower concentrations of nitrate in the early mrnths (Jan-uary through April) of 1977 than in previous years.
This might have l
adversely affected the development of a " normal" spring bloom by making it more difficult for larger (net collectible) species, with their low j
surface-to-volume ratios, to assimilate nitrate at rates sufficient to produce large populations. Such a relationship between phytoplankton l
cell size and nutrient uptake has been reported by Parsons and Takahashi I
(1973).
l l
4.1.2 Indicator Species l
Species considered representative of the New Hampshire coastal 1
phytoplankton assemblage were not very abundant relative to densities 1
i TABLE 4.1-1.
MONTHLY CHLOROPHYLL a CONCENTRATION DATA (mg/m") FROM VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
l t
l YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 0.3 0.2 1.8 1.1 0.6 1.4 1976 1.1 0.6 7.8 1.5 3.9 0.9 1.4 4.9 1.1 1.0 0.8 1.2 1.2 2.0 3.5 1.8 1.3 1975 0.5 1.3 10.6 2.3 4.9 1974 1.2 1.2 2.3-5.8 2.3-2.8 2.3 0.4 1.3 5.7 7.0 2.5 7.0 1.4 i
1973 0.4 0.8-1.3 0.7-2.2 1.0-2.8 0.6 4.5 1.4 1.3-2.5 i
I4 3
TABLE 4.1-2.
C UPTAKE MEASUREMENTS (mgC/m /hr) IN THE VICINITY OF THE PROPOSED DISCHARGE SITE.
SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
4 I
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 0.5' O.5 2.3 4.0 2.5 5.6 1976 0.4 0.3 2.2 0.3 2.3 0.5 0.5 2.0 4.2 2.6 2.1 0.7 1975 4.5 0.7 1.4 9.8 0.7 1.1 h
i i
45 TABLE 4.1-3.
MONTHLY NUTRIENT DATA FROM VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION. SEABROOK ENVIRONMENTAL STUDIES, 1976-1977.
a.
ORTH 0PH0SPHATE (pg P/1)
YEAR J
F M
A M
J J
A S
0 N
D 1977 23 17 12 18 15 7
1976 27 7
2 13 9
8 12 2
9 9
17 12 13 9
12 20 15 34 1975 34 27 16 16 5
1974 29 30 20-29 7-14 7
4 9
5 20 12 21 31 9-12 6-8 5-9 12 17 15-28 24-34 1973 30 b.
TOTAL PH0SPHATE (pg P/l)
YEAR J
F M
A M
J J
A S
0 N
D 1977 42 38 19 21 16 10 1976 33 40 10 25 30 12 27 27 33 51 40 35 21 17 22 27 22 40 1975 49 36 23 24 17 1974 31
--- 23-29 15-22 27 7
18 11 43 16 40 37 10-14 7-12 9-19 18 25 25-32 33-36 1973 32 c.
NITRATE (pg N/1)
YEAR J
F M
A M
J J
A S
0 N
D 1977 5
12 8
8 2
8 24
<1
<1
<1
<1
<1 5
66 62 1976 85 20 1975 47 57 7
14 6
5 4
3 17 11 125 1974 44 56 25-39 10-17 1
8 10 17 8
9 23 45 4-6 2-4 2
16 27 30 41-82 1973 39 l
l d.
NITRITE (pg N/1)
YEAR J
F M
A M
J J
A S
0 N
D 1977
<1
<1 2
3
<1 1
l 1976 4
1 3
2
<1 1
1 1
4 2
4
<1
<1 2
3 2
6 1975 3
2 2
3 1
1974 2
1 1-2 0-1 0
<1
<1
<1 3
1 5
3
<l-2
<1
<1 2
20 3
3 1973 2
1
l 46 recorded for previous years (Table 4.1-4).
Maximum densities recorded in 1977 for Chaetoceros debills, historically most abundant in New Hampshire coastal waters from March through May, were less than 1000 cells per liter, less than previously recorded peaku. Skeletonema costatum was barely evident in samples collected after the December 1976 bloom.
Population densities of Ceratium longipes, usually most abundant from May through August, appeared least reduced compared to previous records.
Monitoring the larger (net) plankton since 1972 has produced a data set which is of primary use in describing long term changes regard-ing taxa such as Chaetoceros and Ceratium which consistently have larger cells. Because of the large sample volumes, the historical presences of rarer species have also been monitored. With respect to short term fluctuations and population changes which affect the smaller-celled organisms, however, the cell count data is of limited use.
General historical perspective on changes affecting the community as a whole can be obtained from the chlorophyll a data which constitute a measure of total phytoplankton biomass.
In July 1977 the phytoplankton program was augmented to include whole water sampling and weekly sampling frequency; frequency of labora-tory analysis has been made contingent on the occurrence of short-lived
" blooms".
Results from these program additions should be of increased benefit in assessment of power plant impact.
4.2 ZOOPLANKTON 4.2.1 General Unlike net phytoplankton cell densities, total zooplankton abundance did not appear to be substantially reduced from densities recorded for the previous 12 month study period (NAI, 1977a).
Dis-regarding enumeration of Nodiolus modiolus straight-hinge veligers on 7
TABLE 4.1-4.
MONTilLY DATA ON TilREE PilYTOPLANKTON INDICATOR SPECIES IN Tile VICINITY- 0F THE PROPOSED INTAKE SITEa FOR Su? SBR 00K STATION, 1972-1977.
SEABROOK ENVIRONMENTAL b
STUDIES, 1976-1977,
a.
CnAET0cEROS DECILIS (CELLS PER LITER)
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT N07 DEC 1977 0
2 7
122
<1 10 1976 3
5 36,700 35,700 169,000 28 0
0 14 0
7 21 1975 0
30 261 6,020 3
0 0
1 1
41 3
1974 0
365 762 22 185 10 0
0 0
0 1
0 1973 88 217,000
<1 1,560 1
0 2
0 0
c 1972 18,300 1,950 2
0 0
<1 b.
SKELETONEMA COSTATuM (CELLS PER LITER) 1977 1
1 2
0 0
0 1976 0
6 0
27 23 135 0
2 4
161 3
1,154 1975 0
28 19 229 0
0 18 1,620 18 114 1
1974 0
13 3
60 19 3
0 50 1,700 9
5 2
1973 1
0 252 3,540 8,700 0
164 38 1,090 c
1972 0
0 2,160 1,040 5
<1 l
l c.
CERATIUM LONGIMES (CELLS PER LITER) 1977
<1 0
1
<1 13 63 1976 2
<1 2
0 25 99 18 42 30 1
1
<1 1975 1
<1 2
96 252 76 32 31 7
<1 9
1974
<1 0
<1 0
0 10 106 21 5
25 32 8
1973
<1 92 206 427 75 1
6 3
1 1972
<1 12 59 51 6
<1
" Data represents means across all replicates surface and bottom, except in 1974-1975 when only surface data were collected.
Note: In previous report (NAI, 1977a) cell densities were incorrectly reported as per m.
Cell counts determined by counting chains and multiplying number of chains by average number of cells in chains.
l t
u
48 October 1976, the 1976-1977 data indicated a summer zooplankton popula-tion peak similar to one which was evident in the 1975-1976 data.
However, in 1975, August collections represented a prominent peak (approaching a density of 57,000/m ), while in 1976, August densities 3
(at 25,700/m ) were slightly exceeded by both July and September values (Appendix Table 7.1-4).
Mesozooplankton biomass estimates tended to follow a seasonal cycle consisting of a winter minimum and a summer maximum.
Biomass estimates for November 1976 and March 1977, which could not be corre-lated to mesozooplankton numerical density (Section 3.2.4), were high relative to comparable monthly estimates from previous years (Table 4.2-1).
However, Table 4.2-1 also indicates relatively high biomass esti-mates in September 1975 and April 1976. Perhaps the explanation given for the November and March values (Section 3.2.4) may also hold true for other values of similarly high magnitude which occurred in months other than June or July.
Numerically, holoplankters were the dominant influence on general patterns of zooplankton distribution.
This, however, does not diminish the ecological importance of meroplanktonic forms which, while occurring briefly as members of the plankton community, constitute a rather vulnerable stage in the life of many marine invertebrates.
Both the present and previous (1975-76) preoperational studies have found bivalve veligers to rank highest among the meroplankton groups, com-prising approximately 8 to 12% of the total zooplankton count.
Gastro-pod veligers ranked second (and noticeably lower) with approximately 2 to 3% of the total zooplankton count.
Polychaete nectochaete and bar-nacle larvae have consistently comprised from 1 to 2% of total zoo-plankton abundance during the past two years of the preoperational l
survey.
l With regard to general patterns of zooplankton abundance and distribution, counts of Modiolus mediolus straight-hinge veligers were treated as an anomaly.
This was deemed necessary due to two factors:
49 3
i TABLE 4.2-1.
MONTHLY ESTIMATES OF ZOOPLANKTON BIOMASS (mg/m DRY WEIGHT)
VARIOUS PERIODS OF STUDY IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION. SEABROOK ENVIRONMENTAL STUDIES, 1976-1977.
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP 0",T NOV DEC 1977 7.0 27 52 12 38 108 1976 5.0 3
16 46 65 20 22 28 20 56 13 1975 9
3 3
18 81 28 50 39 17 15 1974 0.3 2
2-10 3
2 22 48 11 9
7 11 5
1973 22-61 23-31 27-75 18 10 6-20 3-17 m
50
- 1) the once-monthly sampling frequency, which may leave gaps in know -
ledge concerning the occurrence of such a short-lived event (30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />) and 2) the extremely high density of the event in question which would tend to obscure seasonal trends attributable to other species, including other bivalve molluscs.
Concurrent studies with a much higher sampling frequency (twice weekly) are being carried out for definition of bivalve larvae seasonality; 1977 results are reported in Technical Report VIII-2 (NAI, 1978a). It must be regarded as coincidental that the immediate products of a spawning episode, involving this particular species, occurred concurrently with the 4 October 1976, collection date.
Based on evidence from Technical Report VIII-2 (NAI, 1978a) such an event could have co-occurred with any of the sampling dates from July through October.
Ranking present and past holoplankton collections in order of decreasing species abundance (Table 4.2-2) provides some perspective on the representation over time of particular species in the New Hampshire coastal zooplankton assemblage.
Because of the once-monthly sampling, importance should be attached only to the larger shifts in rank order.
Changes in order of numerical abundance which appear to be worthy of attention involve:
- 1) Centropages hamatus and Acartia hudsonica, which appear to have recovered from a population decline of undetermined duration; 2) Paracalanus parvus which appears to be increasing in abundance from the previous study period, when it was first recorded and
- 3) Acartia longiremis which appears to have declined in abundance from the previous year. All of these apparent trends are undoubtedly a composite of true long-term population cycles and various types of sampling variability.
4.2.2 Indicator Species I
1
. A species for which population estimates appear least affected by sampling frequency is the ubiquitous cyclopoid copepod, oithona spp.
Both the present study and a previous report (NAI, 1977a) are consistent 1
51
}
TABLE 4.2-2.
RELATIVE REPRESENTATION OF HOLOPLANKTERS IN THE VICINITY OF HAMPTON BEACH, NEW HAMPSHIRE.
COMPARISON OF 1976-1977 ABUNDANCE RANKING WITH PREVIOUS YEARS. SEABROOK ENVIRON-MENTAL STUDIES, 1976 - 1977.
TAXON 1976-77 1975-76 1974-75 1973-74 1972-73 oithona spp. (Cy) 1 1
1 1
1 Pseudocalanus minutus (Ca) 2 2
3 3
6 Eurytemora herdmani (Ca) 3 7
7 2
3 Microsetella norvegica (H) 4 3
ND ND 8
Centropages typicus (Ca) 5 4
2 4
S Centropages hamatus (Ca) 6 14 ND ND 9
Acartia hudsonica (Ca) 7 15 ND ND 7
Temora longicornis (Ca) 8 5
8 6
4 Calanus finmarchicus (Ca) 9 6
4 10 10 Paracalanus parvus (Ca) 10 17 ND ND ND
~
Metridia lucens (Ca) 11 12 ND ND 3D Evadne spp. (C1) 12 8
6 8
2 Podon spp. (Cl) 13 10 9
7 ND Tartanus discaudatus (Ca) 14 13 10 9
ND Paracalanus crassirostris (Ca) 15 16 ND ND ND Acartia longiremis (Ca) 16 9
ND ND ND I
ND = not determined Ca = calanoid copepod C1 = cladoceran Cy = cyclopoid copepod H = Harpacticoid copepod
52 in indicating little difference in distribution between Hampton Harbor (Station 1) and the open coastal area (Stations 2 and 5).
Another point of agreement between the present and previous study is that Oithona spp.
have a demonstrable affinity for surface waters (Figure 3.2-9). Olthona spp. are abundant at all times of the year, but particularly so from late spring to early fall. Table 4.2-3 indicates that populations have been reasonably stable over the past five to six years.
The indication given by data in the present study (Figure 3.2-
- 7) that Pseudocalanus minutus is more abundant in open coastal areas than in Hampton Harbor is consistent with earlier findings (NAI, 1977a; Sherman, 1965, 1966, 1968, 1970; TRIGOM-PARC, 1974). Over at least the past five years (Table 4.2-4), P. minutus population densities have been reasonably stable, taking into consideration that P. minutus is less abundant than Oithona spp. and exhibits slichtly larger variation in seasonal abundance. Highest densities in more than six years of study were those recorded for 9 June 1977 (Table 4.2-4).
l Preference of Eurgtemora herdmani for inshore areas has been demonstrated in the present study (Figures 3.2-7 and 3.2-8) as well as in previous investigations of New Hampshire coastal waters (NAI, 1974a, 1977).
Historical data indicate a pronounced seasonality in abundance, favoring the mid-summer period, and also suggest that populations may experience a cyclical fluctuation in abundance with perhaps a five to six year period of recurrence (Table 4.2-5).
However, this thesis remains in the realm of speculation pending accumulation of more years of data.
Calanus finmarchicus is even more evident than P. minutus, an offshore species, where it is the dominant copepod of the Gulf of Maine 1
(Bigelow, 1926; Fish and Johnson, 1937; Sherman, 1965, 1966, 1968, 1970).
During the present study period, sexually mature individuals were infrequently caught in bongo tows (maximum occurrences:
3 males and 3 females /m at Station 5, on 8 February 1977). Copepodites, on the other hand, were frequently encountered, most abundantly in spring and
g 3
TABLE 4.2-3.
MONTilLY DATA ON OITHONA SPP. NUMERICAL DENSITY (INDIVIDUALS /m ) IN Tile VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION.
SEABROOK ENVIRONMENTAL STUDIES, 1976-1977.
a.
ADULTS YEAR JAN FEB ftAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 168 88 72 132 1,369 1,502 1976 90 53 206 132 157 1,687 1,164 1,666 400 918 310 274 l
1975 38 40 44 234 364 1,033 404 590 516 783 155 1974 25 37 115 11 43 1,522 896 0
150 2,132 1,162 44 l
1973 58 136 1,034 941 1,034 310 224 697 184 1972 117 776 606 1,982 1,936 131 b.
COPEP0 DITES 1977 214 67 110 907 2,550 5,348 1976 423 77 556 567 808 9,480 10,178 7,793 3,984 4,334 2,585 957 l
1975 3,556 17,387 5,517 5,693 2,059 565 l
1974 0
0 31 20 0
1973 492 936 913 653 115 162 162 15 c.
NAUPLII 1977 456 213 129 1,577 2,151 6,570 1976 405 108 1,018 86 583 4,623 10,672 7,037 4,929 440 594 433 1975 1,202 6,446 2,168 1,352 1,046 903 1974 59 126 181 530 f25 1973 590 1,760 2,185 2,079 306 1,511 113 470 w
54 TABLE 4.2-4.
MONTHLY DATA ON PSEUDCCALANUS HINUTUS ADULT NUMERICAL DENSITY (INDIVIDUALS /m3) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION. SEABROOK ENVIRON-MENTAL STUDIES, 1976 - 1977.
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 210 438 31 12 78 3577 1976 73 29 23 68 106 192 225 49 485 46 491 144 1975 27 71 14 9
315 935 23 146 154 37 121 1974 1
12 43 256 1433 10 13 81 225 17 1973 2
0 486 1917 1233 0
0 1972 2
19 48 54 134 19 l
1 l
55 i
TABLE 4.2-5.
MONTHLY DATA CN EURYTDIORA HERR 61NI NUMERICAL DENSITY (INDIVIDUALS /m ) IN THE VICINITY OF THE PROPOSED INTAKE 3
SITE FOR SEABROOK STATION. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
a.
ADULTS YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 0
1 4
1 418 31 1976 0
1 1
1 3
150 114 9
2 3
2 0
1975 0
10 1
0 45 2
2 1
0 0
0 1974 0
0 0
0 0 1040 0
0 0
0 0
0 1973 1
--- 125i 2156 683 944 48 0
0 0
1972 3
148 872 508 24 O
b.
COPEP0 DITES 1977 0
0 5
10 291 746 1976 1
0 0
0 0
77 20 38 0
51 25 11 1975 9
35 0
0 0
14 1974 0
0 0
0 0
1973 248 1085 209 230 0
0 0
0 f
56 I
summer (Figure 3. 2-3). Historical data (Table 4.2-6) appear to suggest that C. finmarchicus copepodites were somewhat more abundant prior to 1975 than in more recent years. As with E. herdmani, this may turn out to represent a natural long-term population cycle.
57 TABLE 4.2-6.
MONTHLY DATA ON CALANUS FINM1RCHICUS COPEP0DITE NUMERICAL DENSITY (INDIVIDUALS /m3) IN THE VICINITY OF THE PROPOSED INTAKE SITE FOR SEABROOK STATION.
SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1977 3
3 8
5 84 137 1976 1
<1 2
3 9
157 97 272 8
1 10 2
1975 0
0 0
44 157 194 44 48 16 5
3 1974 1
8 17 1416 72 0 2753 148 0
1 0
0 4
2440 650 850 1740 48 90 4
40 1973 1
1972 6
31 10 9
0 P
-y,_-,
..-w.,
,.r
.-y-._m.,
y
.,--.3
.--#,,,w,.--
-.,y-,
,,.m,.,
,... ~.
e
58 5.0
SUMMARY
This report has presented results of plankton surveys under-taken as part of the second annual preoperational monitoring program for Seabrook Station. Specifically investigated were seasonal cycles of abundance and species composition of net phytoplankton, and macro-and microzooplankton, collected monthly from three coastal New Hampshire sampling stations, from July 1976 through June 1977. The study also in-cluded monito.ing of C uptake (primary productivity), chlorophyll a j
concentration, and concentrations of the plant nutrients: orthophos-phate, total phosphorus, nitrate, nitrite and ammonia.
A-total of 107 phytoplankton taxa were identified from water pumped through 76 pm mesh nets.
In general, total net phytoplankton cell densities were found to be unusually low (seldom exceeding 2000 cells per liter) compared to previous years. Chlorophyll a concentra-tions were also found to be ralatively low, exceeding 2 mg/m only during
~
a Chaeteceros spp. bloom which occurred.in early September 1976.
j Nitrate levels which in previous years have ranged from 20 to 85 pg/.
liter during early winter ranged from 8 to 17 pg/ liter in January and l
February, 1977, raising the possibility.that a scarcity of this nutrient may have inhibited the full development of the spring bloom.
Carbon 14 uptake ranged from 0.5 mg C/m /hr in mid winter to 5.7 mg C/m /hr I-during blooms, and did not appear appreciably lower than rates reported in previous years.
Approximately 73 zooplankton taxa were identified from pump and bongo net collections. As in previous years, holoplankters were chiefly represcnted by copepods of which the most important were Olthona spp., Pseudocalanus spp., Eurytemora herdmania Centropages spp. and Microsetella norvegica. Bivalve and gastropod veligers and barnacle and polychaete larvae were the most numerous representatives of the mero-plankton. On 7 October 1976, straight-hinge veligera of the horse mussel, Modfolus modlolus, a principal habitat former on subtidal hard i~
substrates in the immediate vicinity of the plankton sampling stations, 3
was collected in densities averaging more than half a million per m,
59 Of seven planktonic species given special attention as "in-dicator" organisms, two diatoms, Skelecomema costatum and Chaetoceros debilis, exhibited evidence of population decline from the previous annual preoperational monitoring period, while an armored dinoflag-ellate, Ceratium longipes, and three copepods, Oithona spp., Pseudo-calanus minutus, and Calanus finmarchicus appeared to have maintained
{
reasonably stable populations. A fourth " indicator" copepod, Eurgtemora herdmani, appeared to be returning to a level of abundance not observed since 1973.
i
]
l 60 1
6.0 LITERATURE CITED Bigelow, H.B.
1926. Plankton of the offshore waters of the Gulf of Maine.
U.S. Bur. Fish. Bull.
40(Pt. I):1-509.
Fish, C.J. and M.W. Johnson.
1937. The biology of the zooplankton population in the Bay of Fundy and Gulf of Maine with special reference to production and distribution. Jour. Biol. Bd. Can.
3:189-322.
Malone, T.C.
1977. Environmental regulation of phytoplankton pro-ductivity in the lower Hudson estuary. Estuar and Coastl. Mar.
Sci. 5:157-171.
Normandeau Associates, Inc.
1973. Plankton distribution in the estuary and coastal waters in the vicinity of Hampton-Seabrook, New Hamp-shire. Technical Report IV-4.
1974. The impact of entrainment by the Seabrook Station.
Technical Report V-4.
j 1975. Seabrook Environmental Studies. Plankton Monitoring 1974-1975. Technical Report VI-6.
1977a. Seabrook Environmental Studies, 1975-1976. Moni-toring of plankton and related physical-chemical factors. Tech-nical Report VII-5.
1977b. Piscataqua River Ecological Studies, 1976 Moni-tori:tg Studies.
Report No. 7.
j i
1978a. Studies on the soft-shell clam, Nya arenaria, in the vicinity of Hampton-Seabrook Estuary, New Hampshire.
Technical Report VIII-2.
j 1978b. Seabrook Ecological Studies 1976-1977. Finfish ecology investigations in the Hampton-Seabrook Estuary, New Hamp-shire and adjoining coastal waters. Technical neport VIII-4.
i l
Parsons, T.R. and M. Takahashi.
1973. Environmental control of phyto-l plankton cell size.
Limnol. Oceanogr. 18:511-515.
i l
Sherman, K.
1965. Seasonal and areal distribution of Gulf of Maine coastal zooplankton, 1963.
Int. Comm. Northwest Atl. Fish. Spec, i
Publ. 6:611-624.
j 1
[
1966. Seasonal and areal distribution of zooplankton in
[
coastal waters of the Gulf of Maine.
U.S. Fish. Wildl. Serv. Spec.
Sci. Rep. Fish. 530.
lipp.
l l
l i
l j
61 1968.
Seasonal and areal distribution of zooplankton in coastal waters of the Gulf of Maine, 1965 and 1966.
U.S. Fish Wildl. Serv. Spec. Sci. Rep. Fish. 562.
11 pp.
1970.
Seasonal and areal distribution of zooplankton in coastal waters of the Gulf of Maine, 1967 and 1968.
U.S. Fish Wildl. Serv. Spec. Sci Rep. Fish. 594.
8 pp.
Strickland, J.D.H. and T.R. Parsons. 1972. A handbook of seawater analysis. Fish. Res. Bd. Canada.
Bull. No. 167 (2nd ed.).
310 pp.
The Research Institute of the Gulf of Maine.
Public~ Affairs Research Center (TRIGOM-PARC).
1974. A socio-economic and environmental inventory of the North Atlantic region. Volume I, Book 3, Chapter 9: Zooplank*wn.
1 U.S. Environmental Protection Agency.
1973. Biological field and laboratory methods for measuring the quality of surface waters and effluents. EPA 670/4-73-001.
1974. Chemical methods for the analysis of water and wastewaters. Methods Development and Quality Assurance Res. Lab.
Manual.
298 pp.
?
I i'
i i
I i
i f
i f
-._.,x.
. _,, - _ _ _. _,,, _ _ _. _, - - -. -, _,,...... _. ~,,.. _....., _...,....
~ ~ -.
e 7.0 APPENDICES l
l l
t I
l t
l l
l l
l j
I t
TABLE 7.1-1.
TAXONOMIC LIST OF NET PHYTOPLANKTON IDENTIFIED FROM 73 um PLANKTON PUMP SAMPLES JULY 1975-JUNE 1976.
SEABROOK ENVIRONMENTAL STUDIES, 1976-1977.
CLASS: BACILLARIOPHYCEAE ORDER: Centrales I
Actinoptychus spp.
Biddulphia alternans Biddulphia aurita Biddulphia spp.
Cerataulina spp.
Cerataulina pelagica Chaetoceros affinis Chaetoceros atlanticus Chaetoceros boreali.s Chaetoceros brevis Chaetoceros compressus Chaetoceros concavicornis Chaetoceros convolutus Chaetoceros danicus Chaetoceros debilis Chaetoceros decipiens Chaetoceros diadema Chaetoceros didymus l
l Chaetoceros furcellatus Chaetoceros gracilis Chaetoceros laciniosus Chaetoceros lorenzianus Chaetoceros lorenzianus E. forceps Chaetoceros socialis i
Chaetoceros teres i
Chaetoceros spp.
i Corethron hystrix Coscinodiscus centralis l
Coscinodiscus spp.
l Ditylum brightwellii l
Detonula confervacea l
Guinardia flaccida Guinardia spp.
Leptocylindrus danicus Leptocylindrus minimus a
(Continued)
I 4
1 t
2
TABLE 7.1-1.
(Continued) 4 CLASS: BACILLARIOPHYCEAR (Continued)
ORDER: Centrales (Continued)
Melostra moniliformis Melosita nummuloides Melosira spp.
a Paralia sulcata Rhizosolenia alata Rhizosolenia delicatula Rhizosolenia fragilissima Rhizosolenia hebetata Rhizosolenia setigera Rhizosolenia spp.
Skeletonema costatum Stephanopyxis spp.
Thalassiosira nordenskioldii Thalassiosira rotula Thalassiosira spp.
ORDER:
Pennales
]
Achnanthes spp.
}
Amphora spp.
Asterionel1a formosa Asterionella glacialis Campylodiscus echinels Campylodiscus spp.
i Cocconels scutellum Cylindrotheca closterium Fragilaria oceanica Fragilaria spp.
I Grammatophora anyuloca Grammatophora marina Gyrosigma halticum Gyrosigma fascicia Gyrosigma/Pleurosigma spp.
i Isthmia nervosa 1
Licmophora abbreviata Licmophora flabellata Licmophora spp.
Navicula crucigera r
Navicula cf. interrupta Navicula spp.
Nitzschia delicatissima (Continued)
4 TABLE 7.1-1.
(Continued)-
1 1
CLASS: BACILLARIOPHYCEAE (Continued)
ORDER: Pennales (Continued) 4 Nitzschia seriata Nitzschia spp.
Rhabdonema arcuatum Rhabdonema spp.
1 Striatella spp.
Surirella spp.
Synedra spp.
Thalassionema nitzschioides Thalassionema spp.
Thalassiathrix frauenfeldii i
CLASS: CHRYSOPHYCEAE j
ORDER: Dictyochales 4
Dichtyocha fibula Distephanus speculum Ebria tripartita CL:sSS: DINOPHYCEAE ORDER: Prorocentrales i
Ceratium arcticum Ceratium bucephalum Ceratium fusus Ceracia horridt Ceratium lineatun Ceracium longipes Ceratium macroceros Ceratium tripos ll Ceratium spp.
Peridinium depressum Peridinium ovatum i
i Peridinium spp.
Protocentrum micans Prorocentrum spp.
(Continued) i
\\~
4 I
TABLE 7.1-1.
(Continued)
CLASS: DINOPHYCEAE (Continued)
ORDER: Dinopa.ysiales Dinophysis norvegica CLASS: CHLOROPHYCEAE ORDER:
Chlorococcales Pediastrum spp.
Scenedesmus spp.
CLASS: CRYPTOPHYCEAE ORDER: Cryptomonadales Cryptomonadaceae l
i CLASS:
CYANOPHYCEAE ORDER: Chroococcales Merisucpedia (Agmenellum) spp.
ORDER: Oscillatoriales Spirulina subsalsa INCERTAE SEDIS:
Polgasterias problematica A
3 TABLE 7.1-2.
CHLOROPHYLL a VALUES (mg/m ) AT STATIONS IN THE VICINITY OF HAMPTON BEACH, NEW HAMPSHIRE. MEANS AND STANDARD DEVIATIONS REPRESENT FOUR REPLICATES EXCEPT WHEN OTHER-WISE INDICATED. SEABROOK ENVIRONMENTAL STUDIES, 1976 -
1977.
I PERCENTAGE OF c STATION 1 STATION 2 STATION 5 11 MONTH TOTAL 7 Jul 76 2 Aug 76 1.9 1.1 1.4
.1 1.8 t.1 11.4 7 Sep 76 2.1 !.05 9 Sep 76 5.1
.7 4.9 i.3 5.3 t.2 34.2 5 Oct 76 2.5
.1 7 Oct 76 1.6
.2 1.1 t.3 1.4
.4 9.2 8 Nov 76 1.5 t.3 9 Mov 76 1.4 1.2 1.0 1.2
- 1. 4 t.1 8.5 6 Dec 76 1.0 t.2 0.8
.1 0.8
.2 5.8 3 Jan 77 0.3 1.03 0.3 t.05 0.2 t.02 1.8 4 Jan 77
- 0. 4 i.1 7 Feb 77 0.2 t.02 8 Feb 77 0.4 1.02 0.2 t.02
- 0. 2 t.1 1.8 21 Mar 77 2.5 1.0 22 Mar 77 0.8 1.05
- 1. 8 !.1 1.1 t. 06 8.3 13 Apr 77 0.8
.1 1.1 !. 2 1.1
.2 6.7 14 Apr 77 1.9
.05 4 May 77 0.6 !.02 0.6 1.06 0.5
.2 3.8 9 Jun 77 1.0 1.05 1.4 1.1
- 1. 4 t. 2 8.5 I
- values not reported due to suspected contamination during handling bmean & std. dev. of two replicates
- computed only for dates when all three stations were sampled.
}
TABLE 7.1-3.
TAXONOMIC LIST OF SPECIES OR TYPES OF ZOOPLANKTON IDENTIFIED FROM 0BLIQUE 333 um BONGO TOWS (n) AND 76 um PLANKTON PUMP SAMPLES (*), JULY 1976-JUNE 1977.
SEABROOK ENVIRONMENTAL i
STUDIES, 1976-1977.
KEY:
- = Microplankton n = Mesoplankton l
H = Holoplanktonic l
M = Meroplanktonic T = Tychoplanktonic 4
PHYLUM: PROTOZOA SUBPHYLUM: CILIOPHORA ORDER: TINTINNIDA H
PHYLUM: ROTIFERA H
1 Brachionus spp.
.H Notholea striata H
Polyarthra spp.
H PHYLUM: NEMATODA T
y PHYLUM: ANNELIDA CLASS: POLYCHAETA 4
Polychaete eg(s M
Polychaete trochophore M
Polychaete nectochaete larvae M
4 Tomopteris spp, larvae T
n PHYLUM: MOLLUSCA CLASS: GASTROPODA I
Gastropod egg M
Gastropod veliger M
I SUBCLASS: OPISTHOBRANCHIA (VELIGER)
M t
SUBCLASS:
PROSOBRANCHIA i
Littorina littorea eggs M
CLASS: BIVALVIA Bivalve veliger M
Anomia spp. veliger M
Ensis directus veltger M
Modiolus radiolus ve1Lger.
M Mytilus edulis veliger M
Placopecten magellanicus veltger M
(Continued) 4,
_..r,...
,,-~.,,--_._.,,_.-_.,-.......,-,...,,,--,-~.-,~,,.a.-,_-_,---_,,-.---.,.,--..,.,,,,,..,.,----.v,
-TABLE 7.1-3.
(Continued)
PHYLUM: ARTHROPODA CLASS: CRUSTACEA SUBCLASS:
BRANCHIOPODA SUBORDER: CLADOCERA Podon spp.
H G
Evaine spp.
H Q
SUBCLASS: OSTRACODA SUBCLASS: COPEPODi.
Copepoda nauplii H
ORDER: CALANOIDA Calanus finmarchicus copegodLte.
H G
Calanus finmarchicus female H
G Calanus finmarchicus male H
G Paracalanus crassirostris copepodite H
Paracalanus crassirostris female H
Paracalanus crassirostris male H
Paracalanus parvus copepodLte H
Paracalanus parvus female H
G Paracalanus parvus male H
G Pseudocalanus minutus copepodLte H
Pseudocalanus minutus female H
G Pseudocalanus minutus male E
G Pseudocalanus Type A copepodite H
Pseudocalanus Type A female H
Pseudocalanus Type A male H
Rhincalanus nasutus H
G Aetideus armatus copepodite H
G Aetideus armatus female H
Q Aetideus armatus male H
G Euchaeta spp. copepodite H
G Centropages spp. copepodite H
Centropages typicus female H
G Centropages typicus male H
G Centropages hamatus female H
G Centropages hamatus male H
G Pseudodiaptomus coronatus copegodite T
G Pseudodiaptomus coronatus female T
G Pseudodiaptomus coronatus male T
G Tenera spp. copepodite H
Temora longicornis female H
G Temcra longicornis male H
G Eurgtemora spp. copepodite H
Eurgtemora herdmani copepodtte H
G Eurgtemora herdmani male H
G Eurgtemora herdmani female H
G (Continued)
J j
1-
-TABLE 7.1-3.
(Continued)
ORDER: CALANOIDA (CONTINUED)'
Eurgtemora americana female H
G Eurgtencra americana male H
G Eurgtemora affinis female H
G Metridia spp. copepodite H
Q Metridia lucens female H
G Metridia lucens male H
G Candacia armata copepod. e H
G Candacia armata female H
G Candacia armata male H
G Acartia spp. copepodite H
Acartia tonsa H
Q Acartia -hudsonica
(= clausi)
H G
Acartia longiremis H
G Tortanus discaudatus copepodite H
G Tartanus discaudatus female H
G Tortanus discaudatus male H
G Anomalocera opalus copepodite H
G
^
ORDER: HARPACTICOIDA T
Alteutha spp.
T Clytemnestra spp.
T Microsetella norvegica H
Tegastidae T
Tisbe (Idya) spp.
T ORDER: CYCLOPOIDA 4
.Cyclopoid copepodite H
Halicyclops spp. copepodite H
Halicyclops spp. adult H
Oithona spp, nauplii H
Oithona spp. copepodite H
Oithona similis male H
Oithona similis female H
1 Oithona plumifera female H
01thona plumifera male H
Saphirella spp.
H Oncaea spp.
H Macrocheizon spp.
T I
ORDER: MONSTRILIDIDA Monstril11dae M
SUBCLASS: CIRRIPEDIA Cirripedia nauplii M
Cirripedia cypris M
Hansen's nauplii M
SUBCLASS: MALACOSTRACA SUPER ORDER: PERACARIDA ORDER: ISOPODA Epicaridean larvae M
(Continued)
1 TABLE 7.1-3.
(Continued)
ORDER: AMPHIPODA SUPER ORDER: Hyperiidea H
G SUPER ORDER:
EUCARIDA ORDER: EUPHAUSIACEA Euphausid nauplii H
G Euphausid metanauplii H
Q Calyptopis larva H
G Furcilia larva H
G ORDER: DECAPODA Decapod megalopa T
G Caridea zoea M
G Crangon septemspinosa zoea M
G Crangon septemspinosa post 1arva M
G Brachyura zoea M
Q Brachyura megalopa T
G Carcinus maenas zoea M
G Cancer spp. zoea M
Q Pagurus spp. zoea M
Q PHYLUM: BRYOZOA Bryozoan cyphonautes larva M
PHYLUM:
ECHINODERMATA Echinoderm larva M
G PHYLUM: CHORDATA CLASS: LARVACEA H
Q CLASS: ASCIDIACEA Appendicularian type larvae M
PHYLUM: CHAETOGNATHA Sagitta spp.
H G
~.
3 TABLE 7.1-4.
MEAN ABUNDANCE (PER M ) 0F SELECTED ZOOPLANKTON GROUPS BY COLLECTION DATE. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
1976 1977 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN Microzooplankton 30,400 24,600 28,900 15,700^ 11,000 11,600 5,863 3,770 3,930 5,630 20,700 44,100 566,000 Mesozooplankton 1,280 1,120 892 777 1,160 420 274 364 155 118 1,280 3,660 b.
HOLOPLANKTON, MER0 PLANKTON AND TYCH0 PLANKTON.
1976 1977 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN IIoloplankton 24,400 24,200 23,000 9,820 10,100 11,600 5,970 3,940 3,270 5,160 18,360 46,400 Meroplankton 7,040 1,520 6,220 6,450" 1,960 313 154 145 767 540 3,310 1,150 557,000 Tychoplankton 247 44 108 186 75 65 10 49 43 41 257 267 c.
COPEP0D NAUPLII.
1976 1977 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN 7,590 6,630 12,300 4,240 3,490 6,640 1,980 1,930 2,390 2,430 3,690 21,940 a = excluding straight hinge veligers of M. modiolus b = including straight hinge veligers of M. modiolus
3 TABLE 7.1.-5.
ZOOPLANKTON DRY WEIGHT BIOMASS (mg/m ) FROM 333pm MESit PAIRED B0NG0 NET TOWS OFF r ': FiON BEACH, NEW HAMPSHIRE. SEABROOK ENVIRONMENTAL STUDIES, 1976 - 1977.
7 JULY 1976 3 AUGUST 1976 9 SEPTEMBER 1976 i&
i&
2&
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
STATION 1
2 3
4 DEV.
1 2
3 4
DEV.
1 2
3 4
DEV.
6.5 7.3 444 3.0 5.3 1
12.0 2
20.7 10.0 27.7 23.5 20.5 21.0 18.8 24.5 25.2 22.4 29.4 26.7 30.9 23.1 27.5 17.6 13.0 13.4 5
24.6 21.6 41.4 39.8 31.8 91.9 103.9 58.2 65.9 80.0 30.2 18.8 32.9 36.4 29.6 10.2 121.5 17.6 7 OCTOBER 1976 9 NOVEMBER 1976 6 DECEMBER 1976 i&
R&
R&
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
STATION 1
2 3
4 DEV?
1 2
3 4
DEV.
1 2
3 4
DEV.
1 2
24.4 24.6 15.2 17.6 20.4 55.0 59.7 54.3 56.9 56.5 13.3 14.8 11.8 12.6 13.1 4.8 12.4 11.3 5
26.8 24.2 15.2 17.5 20.9 40.2 38.2 55.9 48.7 45.8 26.4-30.4 22.6 29.4 27.2 15.5 18.2.
13.5
TABLE 7.1-5.
(Continued) 3 JANUARY 1977 8 FEBRUARY 1977 21 MARCil 1977 x&
x&
x&
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
SAMPLE-REPLICATE STD.
2
]
STATION 1
2 3
4 DEV.
1 2
3 4
DEV.
1 2
3 4
DEV..
1 4.2 4.1 4.6 3.7 4.2 iO.4 i
2 9.5 7.5 5.8 4.9 6.9 28.8 33.0 22.8 23.4 27.0 59.1 65.1 42.4 41.8 52.1 12.0 14.8 111.8 i,
j 5
13.1 8.2 7.1 8.2 8.4 15.3 19.1 13.6 19.7 16.9 41.4 37.6 21.3 23.0 30.8 11.2 13.0 110.2 1
4 MAY 1977 9 JUNE 1977 13 APRIL 1977 x&
x&
x&
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
SAMPLE REPLICATE STD.
STATION 1
2 3
4 DEV.
-1 2
3 4
DEV.
1 2
3 4
DEV.
i
+
1 28.5 35.'6 32.9 38.4 33.8 18.6 16.3 26.1 23.8 21.2 i4.2 14.5 i
j 2
11.5 12.0 13.5 10.4 11.8 28.4 42.5 43.5 39.1 38.4 L23.5 116.9 95.1 98.3 108.4 l
11.3 16.9 113.9 i
j 5
14.2 13.0 14.1 13.4.13.7 33.2 37.0 45.9 44.6 40.2 74.0 64.9 82.7 95.4 79.2 1
10.6 i6.1 113.0' I
i i
Samples heavily contaminated with silt l
i i
i
- -