HomeMy WebLinkAboutBrown Tide Blooms Perturb Coastal Marine EcosystemEstuaries Vo~. 10, NO. 4, p. 264-290 Dec~mber 1987
Recurrent and Persistent Brown Tide Blooms
Perturb Coastal Marine Ecosystem
ELIZABETH M. COSPER
WILLIAM C. DENNISON
EDWARD J. CARPENTER
V. MONICA BRICELJ
JAMES G. MITCHELL
SUSAN H. KUENSTNER
Marine Sciences Research Cen~er
State University' of ,X~' Yor~
DAVID COLFLESH
MAYNARD DEWEY
Anatomical Sciences
State Universit.¥ of New York
Stony Brook, New York 11794
ABSTRACT: Throughout the summers of 1985 and 1986 a small (2-$ am diameter), previously undescribed
chrysophyte bloomtni monosF~:ifically (> 10' cells 1- ') in Long Island embayments. The bloom colored the water
dark brown, decimated eelgrass b~ls through decreased light penetration and caused starvation (tissue weight loss)
and recruitment failure of commercially important bay ~callop populations. These perturbations portend long-
term changes in subtidal communities. Similar and concurrent blooms in bays of Rhode Island and New Jersey
suggest a meteorological component of the environmental conditions promoting bloom formation. Culture exper-
iments with isolates of the microalga suggest the presence of stimulator)' growth factors in the bloom seawater.
Introduction
Many coastal embayments of Long Island ex-
perienced algal blooms of a small (2-3 ~m) mi-
croalga during the summers of 1985 and 1086 that
were unprecedented in their persistence (~6
months) and cell density (>10° I-~). Virtually
monospecific blooms occurred throughout many
of the inland embayments of Long Island (Fig. 1)
and were popularl) called the brown tide due to
the resulting water color. Reports of similar and
concurrent brown tide blooms in Narragansett Bay,
Rhode Island and Barnegat Bay, New jersey have
been made (Olsen 1986: Sieburth et al. 1986).
Historically, small microalgae generally have
been found to dominate the phytoplankton bio-
mass and productivity in Long Island embayments
such as Great South Bay (Lively et al. 1983) and
the Peconic Bays (Bruno et al. 1983) during the
summer. The brown tide blooms were unique due
to the extreme dominance of a single, previously
unidentified species throughout the summers of
both 1985 and 1986. Usually the small forms ob-
served are diverse and composed of many species
of diatoms, chlorophytes, cryptomonads and small
~ 1987 Estuarr~e ReSearch Federation
284
flagellates (Bruno et al. 1983: Lively et al. 1983).
Primary productivity rates for these bays during
this time are extremely high and do not appear to
be limited by nutrient availability since inorganic
nutrient levels remain relatively high (Bruno et al.
1983: Lively et al. 1983).
The dense algal blooms decreased light pene-
tration and, thus, reduced the extent of eelgrass
(Zostera marl,n) beds. Eelgrass can grow onb to
approximately the Secchi disc depth (Dennison
1987) which, during the algal bloom, was less than
1 m. The 1985 bloom coincided with the spawning
period (June-July) of commercially valuable bay
scallops (Argopectea irradinas irradiaa~0 io the Pe-
conic and Gardiner's bays. These bays contribute
more than 80~ of New York State's bay scallop
harvest, and the bloom resulted in massive recruit-
ment failure of the 1985 year-class. In order lo
document the extent, nature and causes of these
unusual blooms, studies were initiated during the
summer of 1985. Investigations were also con-
ducted to document the impacts of these blooms
on the coastal ecosystems, particularl) on the scal-
lop populations and eelgrass beds.
0160-8347/87/040284-07501.50/0
"Brown Ti~e" Blooms 285
GARDINERS
lO nout miles )AY
RB PECONIC BAYS
~0~ \S~~t~O BP
GREAT SOUTH BAY
Fig. 1. Embayments on Long Island affected (shaded areas) by brown tide blooms during 1985 and 1986. (lslip Marine. l M: Blue
Point, BP; Reeves Ba), RB; New Suffolk, NS)
Methods and Materials
Aerial overflights of Long Island bays (provided
by the New York Air National Guard and the Suf-
folk Count)' Police) and photographic documen-
tation (by R. G. Rowland and W. C. Dennison) were
utilized several times during the summers of 1985
and 1986 to determine the extent and duration of
the blooms. In addition, four field collection sites--
Islip Marina (IM) and Blue Point (BP) in Great
South Bay, and Reeves Bay (RB) and New Suffolk
(NS) in the Peconlc Bays (Fig. 1)--were sampled
on approximately a weekly basis during the sum-
mer months and less frequently at other times.
Surface water samples were collected for phyto-
plankton counts and identification. Chlorophyll a
analyses and primary productivit)' estimates were
made along with measurements of temperature,
salinity by refractometer, and Secchi disc depth.
Microscopic enumeration and identification of
phytoplankton were performed using Lugols and
formalin-fixed samples (Lively et al. 1983). An in-
verted microscope and an epifluorescent micro-
scope were used with DNA-specific fluorescent
stains and light filter sets to distinguish different
species and groups of microalgae. The brown tide
organism was recognized b) the presence of its red-
fluorescing, cup-shaped chloroplast plus the shape
of its nucleus after staining with the fluorochrome
DAPI, Other phytoplankton and codominants,
mainly the small diatom, Minutocellus polynorpbu~,
were recognized by the distinctive shape of their
nuclei and chloroplasts, and cyanobacteria such as
S?ecbococcus were recognized by their orange flu-
orescence under green-light excitation.
Water samples were size fractionated, by passing
water through 5-~m nucleopore filters and 10-
#m nitex screens, so as to compare productivity
and phytoplankton biomass levels of different au-
totrophic size groups (<5 ~m, < 10 $~m. whole).
Fluorometric measurements of chloroph)ll a were
performed on 90cA acetone extracts using methods
of Strickland and Parsons (1972). Estimates of pro-
ductivity, using the uptake of '4C-HCOs during
short-term incubations 00:00-14:00 h under nat-
ural sunlight, were determined (Stricklaud and
Parsons 1972) in duplicate at three light levels (100,
33, and 2~ ambient light). Incubations were ter-
minated b)' filtration onto 0.22-~m Millipore fil-
ters. The filters were dried in a desiccator over-
night in scintillation vials and counted in a Packard
TriCarb 300C scintillation counter after the ad-
dition of Aquasol. Depth profiles of ~4C uptake
rates were constructed and then were integrated
down to the Iq light depth (approximately the
photic zone) and expressed as mg C m : h-h Cal-
culat ions were made to estimate the potential turn-
over rate of photic zone carbon by assuming a C:Chl
a = 45 (Parsons et al. 1977).
During the summer of 1986 isolates of t he brown
tide were established in unialgal culture as de-
scribed in Cosper (1987), using standard isolation
and culture techniques (Guillard 1973: McLachlan
1973). Growth rates of cultures were determined
microscopically using daily hemacytometer counts.
286 E.M. Cosper et al.
Fig. 2. Scanning electron micrograph of the brown tide
species at x:SO,O00 magnification.
Samples for scanning electron microscopy were
fixed in glutaraldeh)de, filtered onto nylon filters,
postfixed with osmium, dehydrated in acetone,
critical-point dried and mounted on stubs for anal-
ysis in a jOEL EX 1200 electron microscope.
Eelgrass (Zostera mari~ia L.) surveys were con-
ducted in August 1986 in Great South Bay and the
Peconic Bays using SCUBA techniques. Water
depth transects throughout Great South Bay and
the Peconic Bays were spaced approximately' 5 km
apart starting south of Islip Marina (IM) at Fire
Island Inlet and heading east out to Gardiner's Bay
(Fig. 1): locations were determined with shore
sightings and Loran. Three sampling stations were
located along each transect. Eelgrass shoot density'
was estimated from five randomly' selected 0.0625
or 0.25 me quadrats. Subsamples of the eelgrass
leaf canopy' were randomly selected, dried (90 *C:
48 h) and weighed. Eelgrass leaf biomass estimates
were obtained from the product of shoot density'
and leaf dry' weight per shoot. In addition to the
three stations along each transect, the maximum
depth penetration of eelgrass was ascertained by
swimming beyond the deepest growing plants. The
area capable of supporting eelgrass growth in the
bay's was calculated by determining the bay bottom
areas between mean Iow water level and the pre-
bloom and postbloom maximum depth penetra-
tion of eelgrass. Prebloom depth penetration was
determined using the report of.Jones and Schubel
(1978) along with field observations made in 1984.
Postbloom depth penetration was determined us-
ing the 1986 depth transects.
For measurements of particle retention efficien-
cy, adult scallops or mussels were individually placed
in a beaker containing 1.5 I of seston collected
during the bloom, artificially enriched with cul-
tured Thalassiosira weissflogii (11 ~m in equivalent
spherical diameter) at 23 *C. This diatom was cho-
sen since Mohlenberg and Riisgard (1975) have
shown that pectinids retain particles greater than
6-7 gm with 100cA efficiency. Gentle stirring main-
tained algae in suspension but prevented the re-
suspension of biodeposits. Mean experimental con-
centrations (calculated as the geometric mean of
algal densities before and after grazing) were
~379,000 cells mi-~ of Aureococcus anorexeffere~s
and 3,300 cells ml-~ of T. weissflogii. Retention ef-
ficiency of A. anorexefferens was calculated as the
clearance rate of this alga (1.6 to 3.2 #m size frac-
tion) relative to that of T. weissflogii (8-16 gm size
fraction) x 100. Clearance rates (volume swept
clear of particles per unit time) were determined
from the change in algal concentrations following
a fixed feeding interval (Coughlan 1969). Particle
concentrations of 30-40 mi samples were deter-
mined using an electronic particle counter (Coulter
Counter, Model TA II).
Results and Discussion
Transmission electron inicroscopy (Carpenter
and Cosper 1986) showed this microalga is a pre-
viously undescribed species and similar to the
chrysophyte species tentatively' desighated Aureo-
coccus a~wrexefferens, which also bloomed in Nar-
ragansett Bay', Rhode Island in 1985 (Sieburth et
al. 1986). Scanning electron microscopy (Fig. 2)
revealed irregular coccoid cells with a shrface in-
dentation and a coating of globular material.
In 1985 the bloom was first noticeable in earlx
June and p~rsisted to late September, reappeare~l
in April 1986, reaching densities of > 10* cells I-~
within several weeks, and persisted into November
at densities of 10~ cells I- ~. The brown tide was not
only' the species that was dominant in terms of cell
number, but also the one that contributed >80%
of total cellular phytoplankton volume throughout
most of the bloom period (Fig. 3) except for two
sampling dates in May and July' ~'hen there were
inexplicable decreases. Primary' productivity rates
of 200 to 400 mg C m-e h-~ were measured in
Great South Bay and the Peconic Bays during the
summer of 1986, consistent with previously doc-
umemed high rates of productivity during the sum-
mcr months (Bruno et al. 1983; Lively et al. 1983).
Estimates of carbon turnover rates ranged from
3.5 to 13 h. The <10 t~m fraction of the phyto-
plankton, generally' dominated by' the brown tide
organism, often contributed >90c~ to total pho-
tosynthetic activity throughout the bloom period
(Table 1). Abundance of the bloom organism dur-
ing the summer remained at ~ 10* cells I- ~ or slight-
70-
o
D~,T E
Fig. $. Percent of total cellular phytoplankton volume con-
tributed b~ the brown tide during the summer of 1986 for
weekly, int~*rx'als sampled at Blue Point (BP).
ly less, and chlorophyll a levels were relatively nor-
mal for these bays during the summer months at
levels of ~ 10-25 ug I-~ (Bruno et al. 1983; Lively
et al. 1983). Changes in phytoplankton biomass,
thus, did not reflect the rapid rates of turnover
estimated from the productivity experiments. Since
dailx sinking rates of such a small microalga would
be s~nall (Smavda 1971) and flushing of the bays is
on the order ~f weeks (Hard)' 1976: Lively et al.
1983), neither of these factors could account for
such constant population densities. Closely coupled
grazing, probably by microzooplankton, most like-
ly served as a control mechanism.
Rapid growth rates (three divisions d-}) of iso-
lates (Cosper 1987) have been obtained in labo-
rator)' cultures under optimum conditions, consis-
tent with the high productivity estimates for field
popu at ons. This microalga grows minimally in
standard media used for culturing marine microa -
gae, f/2 enriched lnstant Ocean Sea Salts (EIO)
(McLachlan 1973), while f/2 media made from
natural filtered seawater (from bloom affected
areas) gives maximal growth rates. Substitution of
sodium glycerophosphate for inorganic phosphate
at equivalent phosphate levels to the f/2 EIO me-
dia enhanced growth to 709~ of growth in natural
seav,'ater media indicating that specific organic nu-
trients are required for rapid growth of this species.
This suggests that there are growth inducing fac-
tors in the bloom water.
The role of light availability in controlling growth
and depth distribution of eelgrass has been eluci-
dated with in situ manipulation experiments (Den-
nison and Alberte 1982, 1985), transplant exper-
iments (Dennison and Alberte 1986) and carbon
balances (Dennison 1987). These studies demon-
strated that light availability controls the maximum
depth penetration of eelgrass and controls eelgrass
"Brown T~" Blooms 287
TABLE 1. Photosynthesis (mgcarb°n m-~ h-~) in the < 10 um
phytoplankton fraction as a percent of the total from the four
sites (see Fig. 1) in Long Island bays (Islip Marina, IM; Blue
Point, BP: Reeves Bay, RB; New Suffolk, NS) in 1986.
June 19 ** 777t ** **
June 26 ** ** 79~ 78q
Jul} 9 997t 957t ** **
Jul) 15 ** ** 100/q 100~
Jub 22 937~ 959~ ** **
August 5 ** ** 1007~ 100/~
August 12 1007~ 91~ ** **
September 18 ** ** 947t 87~
October ] 3 ** ** 96~ 959~
Indicates dates that s~tes were not sampled.
growth in deeper portions of its distribution. Sur-
veys of eelgrass beds were performed to assess the
potential impact of the dense algal blooms, which
decreased light penetration. The Secchi depths
were less than I m (50-60 cm) throughout the
bloom periods in contrast to several meters found
during the summer months in previous years in
these coastal embavments (Bruno et al. 1983: Live-
ly et al. 1983). ThJe increased attenuation of light
during the brown tide blooms is not a consequence
of increased absorption of light by .chloroph)'ll a,
since concentrations remained at levels similar to
those of previous years. Increased scattering of light
due to the small size of this particular phytoplank-
ton species (Jerlov 1968: Morel 1987) is most likel)
the cause of the severe reduction in light penetra-
tion. This decreased light penetration led to a sub-
stantial reduction in eelgrass biomass and depth
distribution (Fig. 4), which resulted in large areas
of Great South Ba) (50 km~) and the Peconic Bays
{65 kin:) that were not capable of supporting eel-
grass growth. These areas represent ~557r of the
prebloom area capable of supporting eelgrass
growth.
Eelgrass beds are crucial to Long Island's shallow
water ecosystems, since the)' influence sedimenta-
tion patterns, nutrient cycling and water flow, and
serve as nurseries for man) species of finfish and
shellfish (Phillips and McRoy 1980). Recruitment
of bay scallops and postsettlement survix al is linked
to the hydrodynamics of eelgrass meadows (Eck-
man 1987) and results in a close association be-
tween eelgrass and scallops (Thayer and Stuart
1974). Eelgrass requires years to decades for re-
cover)' from large-scale mortality, as occurred in
the 1930's (Rasmussen 1977).
Long Island bay scallops spawn in their first year
and experience mass, senescent mortality during
the winter of their second )'ear. Postspawning aduh,
during 1985 (1984 cohort) sho~'ed a 769~ reduc-
288
E. M Casper et aL
EELGRAS$ L;AF BIOMAS$(g/m~')
0 ~00 200 300 400
500
4
Pre-bJoom; Peconic Bays
Pre-bloom~Great South Bay
Post- bloom; Peconic Boys
0---(3 Post-bloom;GreatSouth Bo
Fig. 4. Leaf biomass of eelgrass (Zostera marl~la) vs. water
depth before and after the ! 98.5-198§ algal blooms. Eelgrass
biomass ~,as measured in October 1084 (prebloom) and August
1986 (post bloom) for Peconic Baxs (4 l°00.$'N, 72°18.7'W)and
Great South Bax (40°42 6'N: 72°.58.§'¥,')· Preb}oom data f'or
Great South Ba) gere obtained from Jones and Schubel (1978).
tion in mean adductor muscle dry weight relative
to the previous .~ear (Bricelj et al. 1987). Mortality
rates of this year-class were not documented. Sur-
vivors, however, showed rapid recovery in muscle
· ,,.'eights (three-fold increase during September) af-
ter the bloom subsided, so that tissue weights sur-
passed those of the 1983 cohort by earl)' October
(Bricelj et al. 1987). Thus, New York State landings
of bav scallops in 198.5, although Iow, remained
about' 58c~ of landings averaged over the previous
four-year period (New York State, Department of
Envi(onmemal Conservation, Landings File, 1985).
Experiments with scallops held in cages in situ
indicated that about 307r of the population poten-
tially survived to a second spawning in june 1986
(Bri~relj et al. 1987). Natural restocking was pre-
cluded, however, by recurrence of the bloom in
the summer of 1986. Transplant programs of
hatchery-reared seed into Long Island's embay-
ments were initiated in the fall of 1986 (Rose 1987).
Grazing experiments revealed that bay scallops
retained the brown tide cells with a mean efficiency
1.0-
0.8-
0.6.
0,2'
1.0
0.6
1.2
0
(Vxn) . BAY
~1,0 ~'~1, ~ 51,0 81.0' ~,7 ~6,~ ~
MUSSEL
2.0 3.2 5.0 8.0 12.7 20.2 32
Particle diameter (/~m)
: :Before grozing;o--.oAfter grazing
Fig. 5. Particle biomass (~olume x concentration) mi ' of
a mixed suspension of the bro'~ n tide (2 gm in equix alem spher-
ical diameter, ESD). and Tbaln~do~ira u,e~s~flo~ii (1 I ~m in ESD).
vs. particle diameter, before and after grazing by a represen-
tative bay scallop and blue mussel. Retention et.~ciency o! the
brown tide (se~' text) is calculated from the relative decline of
"small" and "large" algae.
of only 36.1% (SE = 4.0; n = 24), while mussels'
mean retention efficiency for Aureococcu~ was 59.3~
(SE = 2.9: n -- 27). A representative example of
the particle size-frequency distribution before and
after grazing is shown for each bivalve species in
Fig. 5. Starvation, reflected in weight loss of tissues.
occurs whenever the absorbed ration fails to bal-
ance the animal's metabolic energ) expenditure.
Even 36~ retention of brown tide could potentiall5
result in a net energ5 gain at high bloom concen-
trations, and additional explanations are needed to
account for the observed tissue weight losses of
scallops. Furthermore, although mussels are rela-
tively more efficient in retaining the bloom cells,
populations of3L edulis in Narragansett Ba), Rhode
Island, experienced mortalities >95c~ during the
bloom (Trace) 1985). Therefore, inefficient reten-
tion of small particles (<3-6 ~m) by the animal's
gills cannot alone account for the impact of the
"Brown T~e" Blooms 289
brown tide on suspension-feeding bivalves. Possi-
ble mechanisms currently being investigated are
toxicity effects, reduced ingestion rates (concen-
tration-dependent depression of clearance rates
and/or rejection of filtered algae as pseudofeces),
reduced absorption effqciencies at high particle
loads, and/or poor nutritional value of the brown
tide.
The concomitant appearance of the brown tide
over a wide geographic range in noncontiguous
bodies of water, Narragansett Bay, Rhode Island
and Long Island embayments as well as Barnegat
Bay' in New Jersey may indicate a meteorological
component to the environmental conditions pro-
moting bloom formation. Rainfall data obtained
from Brookhaven National Laboratory', Upton,
Long Island indicated that for the first year of the
bloom (1985), rainfall was the third lowest annual
level in the last 37 yr and in 1986, annual levels
were again well below average. Six years of tide
gauge data from Great South Bay', supplied by' the
Suffolk County' Department of Public Works,
Waterways, Division, Yaphank, Long Island, in-
dicates that sea level elevations during 1985 and
1986 were substantially' lower than earlier in the
decade, and as a result, the flushing rate of Great
South Bay would have decreased (Vieira 1986).
Mean sea lex'el (MSL) between January and May' in
1984 was 66cA of MSL for the same months in
1981, ~¥hile in 1985 and 1986 the percentages were
46~ and 62cA, respectively. A trend of decreasing
sea level, attaining a minimum in 1985, coincided
with the first year of the bloom. The great reduc-
tion in rainfall, in spite of the lowered flushing
from coastal waters, led to elevated salinities in the
bay': measurements during the summer for all sites
and dates sampled, with only' one exception at Islip
Marina (IM), were above 25%c and close to 30~/,x,
while in previous years they' have been generally'
25~ (Lively et al., 1983). Hox¥ these conditions
could promote the brown tide blooms needs fur-
ther evaluation.
Recurrence of the brown tide in future years
cannot be accurately' predicted with current infor-
mation and understanding. The brown tide has
reappeared in restricted Long Island embayments
during the summer of 1987 and further research
is ongoing. Chrysophyte species can form cysts as
a stage of their life history', and if the brown tide
species produces cysts which overwinter in shallow
embayments and reseed the pelagic zone during
the spring, this might enhance the recurrence of
blooms in certain areas, similar to recurrent di-
noflagellate red tides (Anderson et al. 1982). The
occurrence of the brown tide two years in succes-
sion has already' severely perturbed Long Island's
coastal ecosystems. Reestablishment of bay' scallop
populations in Long Island waters will depend on
successful restocking of decimated areas, but the
efforts could be inhibited by the loss of eelgrass
habitat.
ACKNOWLEDGMENTS
Research supported by Suffolk Count), New York: Ne~ York
State Sea Grant: Marine Sciences Research Center of the State
University of New York: and The Living Marine Resources
Institute bf the State of Ne~, York. Aerial surseys made possible
by the Suffolk County Police and the New York Air National
Guard. 106 ARRG, Westhampton Beach. Long Island and pho-
tographic documentation by R. George Rowland. We thank Dr.
R. Nuzzi of the Environmental Division of the Suffolk Counts
Health Department for useful comments and Dr. A. Okubo of
MSRC-SUNY for extremely helpful discussions concerning light
attenuation. Contribution No. 598 of the Marine Sciences Re-
search Center of the State University of New York.
LITERATURE CITED
ANDERSON, D. M., D. M. KULIS, J. A. ORPHANOS, AND A. R.
CEU~VEI-'S. 1982. Distribution of the toxic red tide dinofla-
gellate Gon?ulax tamarensi~ in the southern New England
region. Estuarine Coastal Shelf Sci. 14:447-458.
B~.IC£LJ, V. M.,J. Evv, ~gD R. E, MaLOL'L 1987. lmraspecific
variation in reproductive and somatic growth c~cles of bas
scallopsArgoperte, irradian~ 31a~ Ecol. Prog See. 36:123-137.
B~¢£LJ. V. M.,J. EVB, ^~l) R. E. M^t. OOL 1987, Comparative
ph)siology of young and old cohorts of ha,', scallop, Argopecten
irradian~ irradiaas (Lamarck): Mortality. growth and oxygen
consumption. J. Exp. Mar. Biol. Ecol. 112:73-91.
Bgc~o, S. F., R. D. STA~£R, G. M. S~A~S~.',, .~NDj. T. TURNER.
1983. Primar) productivit) and ph~toplankton size fraction
dominance in a temperate North Atlantic estuary.. Estua~e.,
6:200-21 I.
C^g}'I~'¢T£a, E. J., ^~;D E. M. COSP£R. 1986. Culture anahsis,
p. 6. In Proc. Emergency Conference on "Bro~ n Tide," Oct.
23-24, 1986, Hauppauge, Long Island. Stale Dep. of Nex~
York Stale, Albam, New York.
CosP£~, E. M. 19871 Culturing the "Bro~n Tide" alga. App/
Pbycol. Forum 4:3-5.
Couom.^g,J. 1969. The estimation offihering rate from
clearance of suspensions..~la~. Biol. 2:356-358.
D£NNISOg, W. C. 1987. Effects of }ighl on seagrass pholossn-
thesis, growth and depth distribution. Aquatl~Bot 27:15-26
D£Ng~SO~, W. C., A~D R. S. AL~£~TL 1982. Pholosxnlhelit
lions of light intensil;,. Oecologia 55:137-144.
D~NSlSOr~, W. C., ^xt~ R. S. ALBtgT£. 1985. Role ot daih light
period in Ihe depth distribulion of Zode~. marina ~eelgra~sl.
31a~. Ecol Prog Se~. 25:51-61.
D£~Iso~, W. C., A~D R. S. ALa~a~r£. 1986. Pholoadaptation
and growth of Zo.,te~a ma,ha L. (eelgrass} transplants along
a depth gradient. J. Exp. 3]ar Btol Ecol 98:265-282.
EcK~^~.J. 1987. The role of h)drodsnamics in recruitment.
simplex (d'Orbign~.) within eelgrass meado~ s.J E~p 3hl~
Ec,I. 106:165-191.
GUILLARD, R. a. L. 1973. Methods for microflagellates and
nannoplankton, p. 69-85, l~l J. R. Stein (ed.), Handbook of
Ph)cological Melhods, Cuhure Methods and Gros~lh Mca-
surements, Cambridge UniversiD Press, Cambridge.
JERLOV, N. G. 1968. Optical OceanographU Elsexier Publish-
ing Co., Amslerdam 194 p.
JoN£s, C. R., ^~;DJ. R, Scm'att.. 1978. Distribution of surficial
sediment and eelgrass in Great South Ba~, Ne~, York Orom
Smith Point, west to Wantagh State Parkwa',). Mar. Sc~ R,',
290 E~ M ~osper et aL
Ce.terSpec. Re/,. No. 13, MSRC, State Univ. of New York,
Stony Brook. Neb York.
H,~ov, C. D. 1976. A preliminary description of the Peconic
Bay estuary. Ma~ Sci Re~. Ce~lter Spec, Rep,. No. 3, MSRC,
State Uni~. of Neb' York. Ston) Brook, New York.
Lw£~.v.J.S., Z. K,,,vvM^~, ^,~o E.J. C^RV£~V£R. 1983. Phy-
toplankton ecology, of a barrier island estuary: Great South
Ba;,. Ne~ York. E3tuari.e Coastal SbdfSci. 16:51-68.
McL*c:-n..~.J. 1973. Growth media--marine, p. 25-51. In J.
R. Stein (ed.). Handbook of Ph)cological Methods. Culture
Methods and Growth Measurements. Cambridge University
Press, Cambridge.
MOH~.£~£RO, F., AWn H. U. RHSOARO. 1975. Efficiency of
particle retention in 13 species of suspension feeding bivalves.
OphHia 17(2):239-246.
Mo~z~-, A, 1987. Chlorophyll-specific scattering coefficient of
phytoplankton. A simplified theoretical approach. Deep-Sea
Res 34(7):1093-1105.
New YORR STATE DEPARTMENT OF ENVIRONMENTAL CONSER-
V^T~OX. 1985. Landings data file, Stony Brook, Long Island.
O~.sz~;, P. 1986. Occurrence and distribution of brown tide in
New Jerse). p. 10.1. Proc. Emergency Conference on "Brown
Tide," Oct. 23-24, 1986, Hauppauge, Long Island. State
Dep. Neb,, York State, Albany, New York.
P^~so~s, T. R., M. T^z^~^sm, *~;r) B. H^ROR^VE. 1977. Bi-
ological Oceanographic Processes. Pergamon Press, New
York. 3S2 p.
Pmr~-~vs, R. C..^~oC. P. McRov, 1980. Handbook of Seagrass
Biolog~: An Ecosystem Perspectixe. Garland Press, New York.
350 p.
R^s~css~x. E. 1977. The wasting disease of eelgrass (goM~ra
marl.a) and its effects on environmental factors and fauna,
p. 1-52. I. C. P. McRo.~ and C. Helfferich (eds.), Seagrass
Ecosyslems: A Scientific Perspective. Marcel Dekker. New
York.
Rose, J. C. 1987. Scallops transplanted to algae-damaged beds.
Oceans 20(1):6.
SlEw'our-vi, J. MEN., P. W. JoH~$ol~, P. E. H~,Rt;g^v£s. 1986.
(Chrysophsceae): The dominant picoplankter during the
summer 1985 bloom in Narragansett Ba), Rhode Island, p.
5. lu Proc. Emergenc) Conference on "Brown Tide," Oct.
23-24, 1986, Hauppauge, Long Island. State Dep. New York
State, Alban), Neg York.
S~4^v~.,., T.J. 1971. Normal and accelerated sinking of phy-
toplankton in the sea. Mar. Geol. 11:105-122.
STUlCg. I.^~O,J. D, H., ~.~o T. R. P^~so,~s. 1972. A Practical
Handbook of Seawater Anal)sis. Fish. Res. Board Cau Bull
167:1-311.
T:-lt, v£u, C. W., ^~ H. H. S~-V^RT. 1974. The ha) scallop
makes its bed of eelgrass. U.S. Natl. Mar. Fish. Sen% Mar.
R~'. 36:27-39.
T~^c£¥, G. A. 1985. Picoplanktonic algal bloom causes a cat-
astrophic mussel kill in Narragansett Bay, Rhode Island. Traus.
Am. Geoph)s. Uniou 66(51 ): 1303.
Vl£1~t~.. M. B. C. 1986. Summary of background information
by %'. M. Wise, p. 21. la Proc. Emergency Conference on
"Brown Tide,'* Oct. 23-24, 1986, Hauppauge, Long Island.
State Dep. Ne~,' York State, Alban), Neb York.
Received for cousideratio~. August 27, 1987
Accepted for publication. Noaember 16. 1987