Increase In Zooplankton Biomass Research Articles

Can a community of small‐bodied grazers control phytoplankton in rivers?

1. Phytoplankton, zooplankton and grazing were monitored throughout the growing season for three years (1994–96) in the Belgian section of the River Meuse.2. A size structure analysis of the algal community shows that there was a summer shift toward larger algal units, following a decline in phytoplankton biomass. These changes occurred after an increase in zooplankton biomass and diversity.3. Daily filtration rates of grazers ranged from 1 to 113% day–1 and maxima were observed during the summer period. Higher rates tended to correspond with peaks of rotifer biomass. A decline in total phytoplankton biomass within two weeks followed the increase in zooplankton biomass and filtration rate. A rapid biomass recovery was then observed, along with a shift of the algal community toward larger units. When grazing activity was not sustained, due to zooplankton fluctuations, the change in phytoplankton size structure was less marked.4. We suggest that the composition of the phytoplankton community of large rivers may at times be controlled by grazers. However, such biotic interactions can take place only when physical constraints are reduced, i.e. when discharge is low, and when increased transfer time, high temperature and availability of grazeable algae allow high zooplankton biomass.

Cladoceran- and copepod-dominated zooplankton communities graze at similar rates in low-productivity lakes

Many studies suggest that the taxonomic composition of a zooplankton community should determine its grazing rate and selectivity for different types of particles. It is generally believed that copepod-dominated communities should (i) have lower grazing rates and (ii) consume larger particles than communities dominated by large cladocerans. I tested these hypotheses in situ by comparing zooplankton grazing in 19 communities from low-productivity lakes where the zooplankton ranged from >99% copepod biomass to >90% large cladoceran biomass (Holopedium gibberum, Daphnia spp.). The zooplankton grazed 1-14% of total chlorophyll per day and 0-17% of the chlorophyll in algae <35 µm per day. Grazing rates increased with increasing zooplankton biomass (r2 = 0.34, P < 0.01), but once the effect of zooplankton biomass was accounted for, similar grazing rates were found in copepod- and in cladoceran-dominated communities. The difference in grazing rates on small algae and on the whole phytoplankton assemblage, on the other hand, varied systematically with zooplankton taxonomic composition. Holopedium-dominated communities were most efficient at grazing algae <35 µm, Bosmina-dominated communities had similar grazing rates on algae <35 µm and on the whole phytoplankton assemblage, and copepod-dominated communities had similar or slightly higher grazing rates on the whole phytoplankton assemblage. Qualitative differences in grazing selectivity of different zooplankton taxa are observed in complex natural communities.

Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

Zooplankton biomass and species composition were monitored in Cat Arm Lake and Reservoir on Newfoundland's Great Northern Peninsula from 1983 to 1993. Zooplankton biomass increased approximately 19-fold in the oligotrophic reservoir following impoundment in 1984, relative to biomass in the preexisting lake. Microcrustaceans Cyclops scutifer and Daphnia dubia, either rare or absent from Cat Arm Lake prior to impoundment, were consistently measurable components of the zooplankton community by 1993. Similar changes elsewhere have been attributed to both increased water retention time and enhanced phytoplankton biomass, factors whose effects are usually interdependent. In Cat Arm, there were no increases in either phytoplankton biomass or primary productivity during the first 3 years of impoundment, and natality of the dominant cladoceran, Daphnia catawba, did not increase. Summer water retention time increased from preimpoundment levels of 4 days in 1983 to 338 days in 1993. Zooplankton biomass was significantly correlated with water retention time (Spearman's rs = 0.72, p = 0.04) and showed no significant correlation with phytoplankton biomass, primary productivity, nutrient concentrations, pH, colour, or epilimnetic temperature. Changes in the zooplankton community in this subarctic system can thus be attributed most directly to a decrease in losses due to washout.

Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

Grazer and nutrient impacts on epilimnetic ciliate communities

The effects of large grazers (Daphnia) and nutrients (nitrogen and phosphorus) on epilimnetic ciliate communities were investigated in eight large in situ enclosures. Contrasts in Daphnia abundance were created by stocking planktivorous fish (Phoxinus eos) in four of the eight enclosures. Contrasts in nutrients were created by adding nitrate and phosphate to two enclosures with fish and to two enclosures without fish. Both the biomass and mean length of total zooplankton were significantly greater in the fish‐free enclosures than in the enclosures with fish. Addition of nutrients and fish produced a four‐fold variation in concentration of total epilimnetic phosphorus and six‐fold variation in algal biomass (Chl a). Daphnia were virtually absent in the enclosures with fish. The abundance of ciliates was one to three orders of magnitude lower when Daphnia were abundant. Addition of nutrients did not increase ciliate abundance in enclosures with Daphnia, but ciliate mean lengths were larger in these enclosures. Ciliate abundance increased with increasing zooplankton biomass when Daphnia were lacking, but it declined rapidly when Daphnia were abundant, producing a hyperbolic pattern. When the data for all the treatments were considered together, there was no relationship between copepod biomass and ciliate abundance, but positive relationships, although not highly significant, emerged when the data for enclosures with and without fish were considered separately. Our results suggest that large grazers are the most important factor regulating ciliate communities as well as the responses of ciliates to nutrients and resources. Shifts of zooplankton from copepods to Daphnia dominance may result in large reductions in ciliate abundance, regardless of the trophic status of lake ecosystems.

Separate and Combined Effects of Larval Walleye and Fertilization on Plankton Community Structure in Enclosures

ABSTRACT Community impacts of larval walleye (Stizostedion vitreum vitreum) and nutrient addition were examined in an experimental enclosure study. Larval walleye significantly suppressed Daphnia, Diaptomus and Cyclops, but enhanced rotifers. Suppression of zooplankton by larval fish alone did not increase phytoplankton blooms unless fertilizers were added. Nutrient levels (NH3-N, NO3N, and PO4-P) were enhanced in enclosures with fertilizer additions, but were not enhanced in enclosures with both fish and fertilizer additions. Fertilizer applications significantly increased phytoplankton biovolume, pH and dissolved oxygen, but did not increase zooplankton biomass. The highest algal abundance was found in enclosures with both fish and fertilizer additions. This could be due to the release of zooplankton grazing pressure by fish together with nutrient enrichment. Our results suggest that larval fish are important in regulating the zooplankton community, but their effects on phytoplankton depend on nutrient ...

Direct and indirect effects of zooplankton on seston stoichiometry

Abstract:Sestonic particles composed of phytoplankton, bacteria, and detritus are a potential food source for most zooplankton. In the present study, the effect of zooplankton on the stoichiometry of seston was examined in a small eutrophic pond from April to August, because the relative elemental contents of seston relates with phytoplankton growth rate and food quality. In the pond, most of the sestonic particles were edible size (< 30 µm), and sestonic C:P and N:P ratios were high at low zooplankton biomass but low at high zooplankton biomass, suggesting that the zooplankton activity is one of the important factors inducing changes in seston stoichiometry. This possibility was substantiated by grazer gradient experiments that showed a significant increase in the relative P content of the seston with increasing zooplankton biomass. However, slopes of the regression line of the elemental ratios against the zooplankton biomass varied between seasons, and were greater at lower nutrient concentration and hi...

Effect of a Zooplankton Community on Seston Elimination in a Restored Pond in Japan

The rates of seston elimination by zooplankton and primary production were measured in Funada-ike Pond, typical of human-made impoundments in Japan, from April to September in order to evaluate various treatments of the pond aimed at improving water quality by reducing seston abundance. The treatments included draining the pond water, dredging the bottom mud, eliminating the wastewater inflow, and biomanipulation through removal of all fish. After the treatment, seston abundance was reduced from more than 10 to 0.4–2.5 mg C/liter, and large daphnid species, Daphnia similis and D. magna, occurred and predominated in the zooplankton community. Seston abundance remained at a relatively low level from June to August but increased markedly in late August, while the biomass of zooplankton became high from June to mid-August and then decreased. A decrease in seston abundance was found when the elimination rate exceeded the primary production rate. The results indicate that the development of daphnid populations was effective in keeping seston abundance at a low level. The relationship between the rate of primary production and the zoo-plankton biomass required to offset this rate, however, suggests that biomanipulation aimed at increasing zooplankton biomass alone is less effective in a pond with a high primary production. The success in improving water quality in this pond seems to depend not only on the increase in biomass of large daphnid species that resulted mainly from the removal of fish, but also on the decrease in nutrient load that was realized by the other treatments.

The interaction of phytoplankton, zooplankton and currents from 15 months of continuous data in the Mid-Atlantic Bight

Abstract Fifteen months of data from an acoustic Doppler current profiler (ADCP) and three fluorometers obtained during the SEEP-II program in the southern Mid-Atlantic Bight provide a unique view of the seasonal progression of zooplankton and phytoplankton biomass and their responses to physical forcing. Phytoplankton and zooplankton biomass records were highly variable with a continuum of energy at all frequencies and substantial interannual variation. The zooplankton and phytoplankton spring blooms were coincident; that is, the spring increase in zooplankton biomass did not lag behind that of phytoplankton. The spring bloms were not the dominant events of the records, however; the largest fluctuations were linked to current fluctuations, although not always in the same manner. The seasonal succession of zooplankton and phytoplankton species, together with changes in stratification, led to significant differences in the vertical distribution of biomass and its response to physical forcing. There was about a factor of two difference in the maximum zooplankton biomass between two successive springs, while there was no difference in the phytoplankton blooms. Coherence between the phytoplankton, zooplankton and currents were all low. While individual events usually could be ascribed to along- or cross-shelf advective processes, the apparent extreme variability in horizontal biological gradients makes generalizations, aside from those on seasonal time scales, impossible from a single location. Examination of spring bloom data from two successive springs shows a fairly typical relation between primary and secondary production. Thus, the net daily chlorophyll increases ranged from 2.5 to 7.5%, and zooplankton daily ingestion was estimated at 30–55% of primary production, while 38–67% of the daily production was lost to micro-zooplankton, bacteria and the benthos. Zooplankton daily lossed were estimated to be between 25 and 33%. Time-scale estimates for phytoplankton increases agree with incubation values; however, those for zooplankton were much shorter than their reproduction rate, indicating active aggregation behavior.

Nutrient Regeneration by Sockeye Salmon (Oncorhynchus nerka) Fry and Subsequent Effects on Zooplankton and Phytoplankton

Planktivorous fish can affect phytoplankton indirectly by control of herbivore communities, and directly by excretion of soluble nutrients. A field mesocosm study showed that nutrient regeneration by sockeye salmon (Oncorhynchus nerka) fry substantially increased biomass of zooplankton and phytoplankton relative to fishless controls. Plankton communities in enclosures treated with only fish-regenerated nutrients but not fish predation responded differently to two densities of fish. Enclosures with low fish densities exhibited significant increases in zooplankton biomass and small increases in phytoplankton biomass. Nutrients resulting from high fish densities stimulated blooms of ungrazable Dinobryon, and extremely low zooplankton biomass when compared with fishless controls. Phosphorus excretion rates by zooplankton and fish explained 55% of the variance in total plankton biomass in predation-free enclosures and 95% of the variance in chlorophyll a concentrations for enclosures with predators and fish-regenerated nutrients. The results of this experiment suggest that algal production is greatly enhanced by excretion of nutrients by fish, while grazer control is less important.

The importance of zooplankton‐protozoan trophic couplings in Lake Michigan

The importance of the zooplankton‐protozoan trophic coupling was determined experimentally by measured changes in protozoan growth rates with increasing zooplankton biomass. In five of six experiments conducted in Lake Michigan, a significant inverse relationship between protozoan growth and zooplankton biomass was observed (avg r2 = 70%). Zooplankton clearance rates on protozoan assemblages [range, 1.0–6.2 ml (µg dry wt)‒1 d‒1] were comparable to those previously measured for phytoplankton which suggested that protozoa are important prey for zooplankton. Clearance rates on individual protozoan taxa [0–15.6 ml (µg dry wt)‒1 d‒1] were size‐dependent. Rates were greatest for taxa &lt;20 µm in size (mainly nanoflagellates and small ciliates). In contrast to findings for phytoplankton, no evidence emerged for grazer resistance nor growth enhancement by planktonic protozoa in response to grazing. The high flux rates for macrozooplankton on heterotrophic nanoflagellates observed in all experiments (0.2–6.0 µg C liter‒1 d‒1) provided evidence that a large fraction of picoplankton C may be directly transferred to higher trophic levels via a picoplankton‐flagellate‐zooplankton coupling.

Zooplankton-phytoplankton interactions in a eutrophic lake

Enclosure experiments were made in a cyanobacteria dominated lake (Lake Rotongaio) to assess the impact of zooplankton (>150 μm) grazing on algal growth rates and determine the effect of diel and vertical changes in zooplankton grazing intensity and nutrient (NH 4 -N) regeneration upon abundance of phytoplankton. The filamentous cyanobacterium Anabaena minutissima var. attenuata and diatom Cyclotella meneghiniana showed a negative linear change in abundance with a gradient in zooplankton grazing intensity. Phytoflagellates were not grazed and showed a positive linear change in abundance with increasing zooplankton biomass. These effects, as well as shortening of filament length of Anabaena , were caused by raptorial feeding by the alanoid copepod Boeckella propinqua which dominated the zooplankton. Phytoplankton growth was not stimulated by addition of nutrients, suggesting nutrient regeneration was not important. Diel and vertical changes in feeding and NH 4 -N regeneration rates were measured in March and June 1988. Diel differences were more pronounced in March when the water column was stratified. Specific feeding rates were more important than vertical changes in zooplankton biomass in determining community grazing rates in March, but in June when the water column was mixed, vertical distribution of zooplankton biomass was important. Zooplankton grazing was an important loss process for phytoplankton in the lower part of the epilimnion in Lake Rotongaio.

Density-Dependent Growth and Survival of Larval Ambystoma: Evidence from Whole-Pond Manipulations

To determine whether growth and survival of marbled salamander larvae were density dependent under natural conditions, I established hatchlings at either natural density or one—fourth natural density in paired halves of 11 natural ponds. I sampled ponds at 7, 11, and 15 wk and at the initiation of metamorphosis, comparing percentage of larvae injured, larval size, and larval survivorship. I also compared density, size, and biomass of zooplankton, the dietary staple of larvae. Reducing density increased mean larval body size on all sample dates except week 7, and mean size at the initiation of metamorphosis was negatively correlated with average larval density during the larval period. Mean size at the initiation of metamorphosis was correlated positively with average zooplankton biomass during the larval period, which suggests that food was limiting in many ponds. Surprizingly, however, reducing larval density did not increase zooplankton biomass, number, or density relative to controls. Density reductions significantly increased larval survival on all sample dates. Many populations exhibited Type II survival, but survival tended towards Type I at sites where ponds contracted severely near the end of the larval period. Mortality associated with pond contraction was due to changes in biotic or physical factors associated with pond contraction, and not to desiccation per se. Most larvae suffered tail damage caused by attacks from conspecifics and/or invertebrates. high larval mortality in contracted ponds was associated with increased larval density and injury frequency. The proportion of animals showing tail damage was significantly less in reduced—density treatments compared to natural—density treatments. Tail—damaged animals were smaller than undamaged animals, perhaps because loss of tail tissue compromised growth. Because larvae did not reduce zooplankton biomass, it is unlikely that exploitative competition for zooplankton was the primary cause of density—dependent growth and survival. My data suggest that intraspecific aggression may be more important than exploitative competition in explaining density dependence in Ambystoma larvae.

Regulation of zooplankton by suspension-feeding bivalves and fish in estuarine enclosures

Enclosure experiments were conducted during April. June/July and September in the eutrophc estuary Roskilde Fjord, Denmark, to reveal the effects of inorganic nutrients, suspensionfeedng bivalves Mytilus edulis and planktivorous fish (three-spined sticklebacks Gasterosteus aculeatus) on the zooplankton community > 45 pm. The additlon of inorganic nutrients did not increase zooplankton biomass although it did increase the chlorophyll level, indicating that zooplankton production was not food hmited. Filtration by M. edulis reduced the number of tintinnid ciliates and rotifers during all 3 experiments, but not the abundance of the larger zooplankton species. Additions of planktivorous fish reduced the densities of larger zooplankton species Acartia tonsa and Pleopis polyphernoides but not of smaller species. An immense increase in numbers of A. tonsa and P. polyphernoides was observed in enclosures without fish, indicating that the larger crustacean zooplankton is strongly predator controlled. Thus, the qualitative and quantitative development of the zooplankton community in the enclosures was controlled in 2 ways; from the top of the size spectrum by G. aculeatus and from the bottom of the size spectrum by M. edulis.

Regulation of Lake Primary Productivity by Food Web Structure.

We performed whole-lake manipulations of fish populations to test the hypothesis that higher trophic levels regulate zooplankton and phytoplankton community structure, biomass, and primary productivity. The study involved three lakes and spanned 2 yr. Results demonstrated hierarchical control of primary production by abiotic factors and a trophic cascade involving fish predation. In Paul Lake, the reference lake, productivity varied from year to year, illustrating the effects of climatic factors and the natural dynamics of unmanipulated food web interactions. In Tuesday Lake, piscivore addition and planktivore reduction caused an increase in zooplankton biomass, a compositional shift from a copepod/rotifer assemblage to a cladoceran assemblage, a reduction in algal biomass, and a continuous reduction in primary productivity. In Peter Lake, piscivore reduction and planktivore addition decreased zooplanktivory, because potential planktivores remained in littoral refugia to escape from remaining piscivores. Both zooplankton biomass and the dominance of large cladocerans increased. Algal biomass and primary production increased because of increased concentrations of gelatinous colonial green algae. Food web effects and abiotic factors were equally potent regulators of primary production in these experiments. Some of the unexplained variance in primary productivity of the world's lakes may be attributed to variability in fish populations and its effects on lower trophic levels.

Species-specific algal responses to zooplankton: experimental and field observations in three nutrient-limited lakes

A series of 4-day manipulations of zooplankton biomass and nutrient availability was performed in enclosures in three lakes to determine species-specific algal responses to herbivory and nutrient enrichment. Algal performance in enclosures was compared to the relationships between weekly algal growth rates and the zooplankton in situ . When in situ growth rates were significant functions of zooplankton biomass, the responses were generally consistent with responses in the enclosure experiments. The importance of both nutrients and zooplankton in mediating algal growth was demonstrated by numerous observations: strong algal community response to enrichment, unimodal or positive responses of certain algal taxa to zooplankton biomass, differences in degree of nutrient limitation among the algal response types, lack of nutrient limitation of non-grazed algal taxa and a preponderance of taxa with no net response to increasing zooplankton biomass. Variation in the zooplankton community may be the largest source of variability in nutrient supply rate during summer in stratified lakes, and causes substational variability in the algae. Algae responded more strongly to changes in zooplankton composition than to changes in zooplankton biomass. We conclude that, due to the close coupling of phytoplankton and zooplankton communities in these nutrient-limited lakes, major compositional changes in the zooplankton have greater effects on the algae than do changes in biomass of grazers already present.

Particulate matter production and consumption in deep mixed layers: observations in a warm-core ring

Particulate matter variability is described in the contect of biological and physical processes in the core waters of WCR 82B between February and late June 1982. WCR 82B formed in mid-February with a probable mixed layer depth of 50 m. A series of heat loss and convective mixing events deepened the mixed layer to >300 m by March and to 400 m by early April 1982. Periods of convective mixing and transient stratification in the deep mixed layer were indicated by chlorophyll, nutrient, and temperature data collected during the last 10 days of April. Seasonal stratification was established by early May, and the core waters of WCR 82B became strongly stratified shallower than 40 m by June. Particulate matter samples were collected from the upper 1000 m by large volume in situ filtration in April and June 1982. Vertical distributions were obtained for particulate dry weight, organic carbon, calcium, biogenic silicon, and phosphorus as well as abundances of >1 mm size fecal matter and fecal pellets. The data show that particle production exceeded particle consumption by zooplankton in the euphotic zone from February to April. However, the particle concentration remained nearly constant in the euphotic zone, but increased between 50 and 400 m during this period. These observations suggest that mixed layer convection in March and April removed a significant fraction of particles from the euphotic zone into the deep thermostad. Analysis of the data shows that 67% of primary produced carbon was mixed into the thermostad during this time. Such conditions were favorable for the growth of herbivorous zooplankton which were dispersed several hundred meters below the surface. Comparisons of the standing stock of particles present in the upper 400 m in late April with supply rates of material due to down mixing suggest that the particle populations in this zone turn over on time scales of 10 days. After onset of seasonal stratification in early May, the down-mixed supply of newly produced carbon to deep thermostad waters was eliminated. Because the rates of euphotic zone particle production and loss were no longer balanced, a bloom of phytoplankton peaking in mid-May may have occurred. Observations showed that particles were removed from the thermostad between April and June, and calculations suggest that this loss (by zooplankton consumption) may have occurred in as short a time as one week following seasonal stratification. Following the removal of utilizable particulate matter, zooplankton shoaled to become concentrated in the upper 50 m by June. The continued high rate of primary production and the strongly increased zooplankton biomass in the upper 50 m in June resulted in enhanced production of fecal material in the upper 40 m. The high rates of zooplankton grazing in June resulted in the removal of most aggregate material by 110 m. These observations demonstrate that the coupling of physical, biological and chemical processes in the upper ocean occurs on time scales as short as 10 days. They also show that particulate matter is a sensitive indicator of the balance between production and removal processes in the upper 1000 m. Our data suggest that (1) zooplankton consumption as opposed to dark respiration is the dominant loss mechanism for phytoplankton carbon mixed below the euphotic zone into deep mixed layers, and (2) the imbalance between production and removal processes in the euphotic zone at the time of stratification caused by the cessation of mixing to depths below the euphotic zone leads to the development of the spring phytoplankton bloom.

Temporal and spatial changes in epipelagic microzooplankton and mesozooplankton biomass in warm-core Gulf Stream ring 82-B

The vertical distributio of > 64 μ m zooplankton biomass in warm-core Gulf Stream ring (WRC) 82-B was studied when the ring was approximately 2,4 and 6 months old. Variability of zooplankton biomass estimates in 82-B was not significantly different on diel, 5 to 12 day, and seasonal (April, June, August) time scales as the ring evolved from its Sargasso Sea origin. Zooplankton biomass in 82-B was similar to concentrations found in the Slope Water. The average ratio of integrated (0 to 200 m) zooplankton ( > 64 μ m ) biomass in the surrounding Slope Water to that in 82-B was 1.6 at 2 months old and 0.7 at 4 months. Small zooplankton (64 to 333 μm), dominated by copepod nauplii and copepodite stages, increased from 376 mg C m −2 in April (26% of total zooplankton biomass ) to 427 mg C m −2 in June (35% of total biomass), suggesting that the zooplankton were producing more juveniles. Increased zooplankton biomass in WCR 82-B between April and June was likely a result of both in situ growth and the lateral advection of Slope Water zooplankton into the ring. Many zooplankton species which increased in WCR 82-B were of Slope Water origin. These apportunistic species of calanoid and cyclopoid copepods appear capable of exploiting the often high phytoplankton production and standing crops of WCRs, and result in a rapid evolution of the WCR epipelagic zooplankton community from its Sargasso Sea origin.

Response of Onondaga Lake to Restoration Efforts

The continuing restoration program for polluted, hypereutrophic Onondaga Lake, is examined, including descriptions of ecosystem responses to reclamation measures and evaluations of the various characteristics specific to the lake as they may affect future responses. Major responses to the program have included: (1)Substantial changes in phytoplankton composition; (2)reduction in concentrations of heavy metals; and (3)a dramatic increase in zooplankton biomass. Despite a major reduction in phosphorus loading, phytoplankton biomass has remained essentially unchanged. Further reductions in phosphorus loading, anticipated with the new (1981) tertiary sewage treatment plant, may result in phosphorus limited phytoplankton growth. The increase in zooplankton implies increased phytoplankton turnover rates and phosphorus recycling within the lake, which may prolong future phytoplankton blooms.

Changes in the zooplankton of Onondaga Lake (NY), 1969–1978

The zooplankton of polluted, hypereutrophic Onondaga Lake (located in metropolitan Syracuse, NY) were reinvestigated during 1978 to identify changes in the community since 1969. The reduction in large daphnids since 1969 has been attributed to size-selective predation by the obligate planktivore, Alosa pseudoharengus, which has become re-established in the lake. A 10- to 20-fold increase in zooplankton biomass has occurred since 1969, which may have been in response to changes in phytoplankton composition and/or reductions in metal pollution resulting from lake reclamation efforts. Increases in grazing on phytoplankton, phytoplankton turnover rates and nutrient recycling are implied by the elevated levels of zooplankton biomass. These zooplankton-phytoplankton interactions may be critical to future reclamation efforts directed at reducing external nutrient loading and primary productivity.