Zooplankton Succession Research Articles

Comparison of Two Target Phosphorus Concentrations for Fertilizing Florida Largemouth Bass Spawning Ponds

Abstract Two target concentrations of phosphorus (P) were compared in fertilized spawning ponds of Florida largemouth bass (Micropterus salmoides floridanus) to evaluate reducing P application rates to control the growth of filamentous algae. Pond P concentrations were restored weekly to 1.0 mg/L (high-P treatment) or 0.5 mg/L (low-P treatment). All ponds received the same nitrogen and organic fertilization regimen. Fish production, zooplankton densities, phytoplankton biomass, nutrient levels, and the percent coverage of the pond surface by filamentous algae were measured. Both treatments provided adequate P for phytoplankton and zooplankton development and were low enough to avoid excessive growth of filamentous algae. Total lengths, weight, and number of fingerling largemouth bass harvested were similar between the two treatments. Zooplankton succession differed between the two treatments. Phytoplankton biomass and zooplankton densities increased more rapidly and reached higher maxima in high-P ponds t...

Seasonal dynamics of crustacean zooplankton, heterotrophic nanoflagellates and bacteria in a shallow, eutrophic lake

SUMMARY1. The seasonal development of crustacean zooplankton, heterotrophic nanoflagellates (HNF) and bacteria was examined in Grosser Binnensee, a shallow, eutrophic lake in northern Germany. The grazing impact of Daphnia on bacteria and nanoflagellates was estimated from field data on population abundances and from clearance rates obtained in laboratory experiments.2. The seasonal succession of zooplankton showed distinct peaks of Daphnia magna, cyclopopid copepods, Bosmina longirostris and Daphnia galeata and D. hynlina. The population dynamics of Dapfinia had the strongest impact on all sestonic components. Daphnia maxima coincided with clearwater phases, and were negatively correlated with particulate organic carbon (POC), HNF and phytoplankton. Bacterial abundance was only slightly affected although daphnids were at times more important as bacterial consumers than HNF, as estimated from measured bacterial clearance rates. Other crustaceans (copepods, Bosmina) were probably of minor importance as grazers of bacteria and nanoplankton.3. HNF abundance varied from 550 ml−1 to more than 30000 ml−1. HNF appeared to be suppressed by daphnids and reached highest densities when copepods dominated the metazooplankton. The variation in HNF abundance was not reflected in the concentration of heterotrophic bacteria, which fluctuated rather irregularly between 5 and 20 ± 106 ml−1. Long filamentous bacteria which were probably resistant to protozoan grazing, however, appeared parallel to the development of HNF. These bacterial cells, although small in number, could comprise more than 30% of the total bacterial biomass.

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.

Effects of trichlorfon, fenthion, and diflubenzuron on the zooplankton community and on production of reciprocal-cross hybrid striped bass fry in culture ponds

The application of trichlorfon, diflubenzuron, or fenthion to fertilized culture ponds stocked with 5-day-old, reciprocal-cross, hybrid striped bass fry resulted in an initial reduction in the concentration of rotifers and longer-term alteration of zooplankton successional stages, including changes in concentrations of rotifers, cladocerans, and copepods. Culture ponds without applied chemicals had the highest concentrations of small rotifers when fry were stocked, followed by high concentrations of cladocerans, copepod nauplii, and adult copepods. Fry survival in untreated ponds was higher than in chemically-treated ponds. Initial high concentrations of copepods in some ponds corresponded with low fry survival. Untreated ponds that were filled at the time of broodfish spawning, and stocked with fry 5 days later, had the highest fry survival rates, corresponding with peak rotifer concentrations, followed by a typical zooplankton succession.

Limnology of rearing ponds for Australian fish larvae: Relationships among water quality, phytoplankton, zooplankton, and the growth of larval fish

Fertilization of earthen ponds used to rear the larvae of golden perch, Macquaria ambigua, and silver perch, Bidyanus bidyanus, resulted in phytoplankton blooms dominated by the cyanobacterium Anabaena possibly because of a low N:P ratio. There was a zooplankton succession of rotifers (mostly Brachionus), Moina, Boeckella and Mesocyclops, and then Daphnia. An increase in Daphnia correlated with a decline in Anabaena, suggesting grazing on that cyanobacterium. Golden perch larvae included copepods in their diet whereas silver perch did not, and this was reflected in lower Boeckella numbers in the golden perch ponds. There was sufficient zooplankton forage, supplemented by chironomid larvae in the later stages of the rearing ponds, for fish growth. The limnological conditions and zooplankton communities in these ponds provide a model for evaluating nursery grounds for these fish.

ASPECTS OF COMPARATIVE PLANKTON ECOLOGY IN CASCADING MGENI RIVER RESERVOIRS (MIDMAR, ALBERT FALLS, AND NAGLE): AN OVERVIEW

Summary An overview of a three year study of abundance, community structure and succession of zooplankton and phytoplankton in relation to physical limnological conditions in Lakes Midmar and Albert Falls is presented, along with findings on zooplankton from a nine month study of Lake Nagle. Physical stability increased between Midmar (mean summer N2 = 6.55 × 104 s2) and Albert Falls (N2 = 8.70 × 104 s2), in line with elevations in water temperature. Phytoplankton richness and diversity was similar in these reservoirs, although zooplankton species richness increased downstream. Abundance levels of both phyto- and zoo-plankton were broadly comparable in these two reservoirs. In Midmar and Albert Falls, overall mean (± SD) chlorophyll levels were 3.60 ± 1.54 and 3.41 ± 1.41 μg 11, with corresponding overall average zooplankton standing stocks of 0.85 and 0.76 g m2 dry mass, dropping to 0.54 g m2 in Nagle (for which spring to midsummer data are missing). Ruderal and colonist phytoplankters were persistently dominant both in Midmar and Albert Falls, in keeping with the continuous (if incomplete) mixing patterns evident in these reservoirs. Few stress tolerant algae occurred. The summer ruderal assemblage was unexpectedly dominated by diatoms in the physically more stable conditions of Albert Falls, but not Midmar. Mean zooplankton grazer-induced instantaneous mortality rates for planktonic algae for the whole study were estimated (by regression predictions) as 0.17 d1 in both lakes. Phytoplankton was not studied in Nagle. Changes in zooplankton community structure between Midmar and Nagle largely involved progressive increases in the contribution of smaller-bodied cladocerans (comprising both sequentially smaller species of Daphnia (D. pulex, D. longispina, D. laevis), and additional genera such as Diaphanosoma, Ceriodapnia, Moina and Bosmina). As with a parallel progressive switch between Metadiaptomus meridianus and Tropodiaptomus spectabilis over this series of reservoirs, (and the temporal separation of “co-existing” populations in Albert Falls), which has been shown experimentally to be strongly temperature-linked, changes in absolute temperature are implicated as a primary causal factor in the shifts in cladoceran species composition. Temporal occurrences of these species also indicate the primacy of temperature.

Seasonal Succession and Vertical Distribution of Zooplankton in Lake Ozenuma.

Seasonal succession and vertical distribution of zooplankton in the central region of Lake Ozenuma were studied during icefree seasons in 1987 and 1988. Rotifers were more abundant in density than cladocerans. Copepods were rare. The most dominant species were Polyarthra trigla in Rotifera and Bosmina longirostris in Cladocera. In biomass, however, cladocerans usually surpassed rotifers, and the cladoceran Holopedium gibberum took the highest percentage of the total zooplankton biomass. Some zooplankton species were found commonly throughout the study period, whereas others appeared irregularly. It seems that, in recent years, rotifers have become more abundant in the lake.

Zooplankton succession in the River Odra estuary

Changes in the dominance structure of zooplankton in the River Odra estuary were studied over the years 1984-1988; samples were collected 4 times a year. Frequency distribution analysis of dominants and subdominants was carried out to outline a hypothetical pattern of succession in the area of study. The following filtrators were found to mainly influence the spatial structure of the zooplankton: Daphnia cucullata, Bosmina coregoni and Bosmina coregoni maritima, the advanced eutrophication of the estuary resulting in abundant food resources in the form of phytoplankton.

Cladoceran assemblages, seasonal succession and the importance of a hypolimnetic refuge

SUMMARY. 1. We investigate the importance of a refuge from fish predation to the abundance, species composition and seasonal succession of zooplankton. Thirty lakes representing a range of depths were sampled twice in summer for physical/chemical parameters and zooplankton community structure.2. We define the refuge from centrarchid predators to be that space between the thermocline and the zone of anoxia. As lakes vary in rate of oxygen depletion from the hypolimnion. the refuge size and lake depth are independent: refuge size decreases during the summer period.3. Lake depth and refuge size independently explain variation among lakes in zooplankton species composition, but seasonal community change within lakes is best predicted by loss of refuge size.4. Refuge size also explains the substantial variation in the relative dominance of the two major daphnid species. Lakes possessing a large refuge are dominated by D. pulicaria; those with a small refuge are dominated by the smaller, D. galeata mendotae. We suggest that lakes of intermediate refuge size, which are characterized by high species diversity, represent a more equitable balance of predation and competition.

Zooplankton Seasonal Succession in Lake Ontario at Northshore, Midlake, and Southshore Stations in 1982, and a Comparison with 1970

The seasonal pattern of zooplankton succession in Lake Ontario was similar at three stations along a north–south transect, with differences attributable to physical factors. Because of warming within the thermal bar zone, the spring succession at the northshore station was early relative to the midlake station, but after stratification the northshore station lagged behind due to frequent upwelling events. Thermal bar formation along the south shore was followed by downwelling throughout the summer, giving a deeper epilimnion. These events may have contributed to not only the greater biomass at this location, but also succession which preceded that at the other stations during summer and fall. The species composition and the timing of the summer succession were very similar to those reported for 1970. Lake Ontario zooplankton did not change markedly in response to changes in nutrient loading and salmonid predators during the 1970's.

Resource‐mediated demographic variation during the midsummer succession of a cladoceran community

SUMMARY. 1. The midsummer succession of cladoceran zooplankton in Lake Texoma was examined by demographic characterization of lake populations and a parallel set of life table experiments in which the dominant cladoceran species were raised on naturally occurring lake phytoplankton at lake temperatures. Diaphanosoma leuchtenbergianum occurred throughout the study period (mid June‐mid August 1981) but Daphnia parvula, D. galeata mendotae and Ceriodaphnia lacustris were rarely detected after 15 July.2. Analyses of size structure and size‐specific fecundity of the cladoceran populations showed that (1) size structure shifted to smaller individuals in mid July, (2) size‐specific fecundity was relatively constant in the smaller size classes and was constant or declined in larger females of each species, and (3) size at maturation did not vary significantly during the study of any population.3. Individual growth rates of the two Daphnia species and Ceriodaphnia in the life table experiments were significantly lower in mid July when populations were declining and when size structure of each population was more dominated by smaller Individuals. The reduction in individual growth rates was short‐lived in the life table experiments; growth rates returned to pre‐decline levels by the end of July.4. Two effects of temporary reductions in individual growth rates when size‐specific fecundity and size at maturation are constant are (1) that size structure is temporarily shifted to smaller individuals, and (2) the potential rate of population growth is reduced because of delays in reproduction. Because data on size structure and size‐specific fecundity are commonly used to evaluate the relative effects of predators and resource changes on populations it is noteworthy that erroneous conclusions about the mechanism of population decline may be reached when individual growth rates vary.

Species Composition and Seasonal Succession of the Zooplankton Community of Eutrophic Lahontan Reservoir, Nevada

Species Composition and Seasonal Succession of the Zooplankton Community of Eutrophic Lahontan Reservoir, Nevada

Seasonal dynamics of rotifer and crustacean zooplankton populations in a eutrophic, monomictic lake with a note on rotifer sampling techniques

The abundances, biomass, and seasonal succession of rotifer and crustacean zooplankton were examined in a man-made, eutrophic lake, Lake Oglethorpe, over a 13 month period. There was an inverse correlation between the abundance of rotifers and crustaceans. Rotifers were most abundant and dominated (>69%) the rotifer-crustacean biomass during summer months (June–September) while crustacean zooplankton dominated during the remainder of the year (>89%). Peak biomasses of crustaceans were observed in the fall (151 µg dry wt l−1 in October) and spring (89.66 µg dry wt l−1 in May). Mean annual biomass levels were 46.99 µg dry wt l−1 for crustaceans and 19.26 µg dry wt l−1 for rotifers. Trichocerca rousseleti, Polyarthra sp., Keratella cochlearis and Kellicottia bostoniensis were the most abundant rotifers in the lake. Diaptomus siciloides and Daphnia parvula were the most abundant crustaceans. Lake Oglethorpe is distinct in having an unusually high abundance of rotifers (range 217–7980 l−1). These high densities can be attributed not only to the eutrophic conditions of the lake but also to the detailed sampling methods employed in this study.

The Zooplankton Community of Lacygne Lake: A Cooling Pond in Kansas

This study provides baseline data on the zooplankton community of LaCygne Lake before its use as a cooling pond and documents changes occurring after startup of the electrical power generation station. The spring zooplankton maximum shifted from July during the summer before plant operation to May and April in the two successive years after plant operation began. Zooplankton density increased significantly after the plant began operation. In situ thermal toler- ance experiments simulated passage through the condenser and discharge canal by exposing zoo- plankton 4 h to temperatures ranging from 35° to 40°C. Bosmina longirostris was the most heat resistant species. B. longirostris increased in density more than other zooplankton species after plant startup. Reservoirs are increasingly being used as cooling ponds to dissipate heat produced during the generation of electrical power. Use of a lake as a cooling pond can potentially affect the lake zooplankton community in many ways. The plant may cause zooplankton mortality when water from the cooling pond is pumped through the plant to remove heat from the steam condensers. Water emerging from the condenser is usually heated from 6 to 17°C above ambient lake temperatures (Clark, 1969) and may ultimately reach tempera- tures above zooplankton thermal tolerances, favoring population growth of heat resistant species. Another effect is that the discharge of the heated con- denser effluent back into the cooling pond may increase lake temperatures and alter zooplankton succession which is, in part, temperature dependent (Hall, 1964; Hutchinson, 1967). Most research related to the zooplankton of cooling ponds has focused on zooplankton thermal tolerance or mortality caused by condenser entrainment (Finesinger, 1926; Brown and Crozier, 1927; Brown, 1929; Heinle, 1969; Goss and Bunting, 1976; Carlson, 1974; Storr, 1974; Buikema et al., 1978). Few stu- dies have examined the combined impact of condenser passage and lake heat- ing on the zooplankton community of the cooling pond (Carlson, 1974; Krza- nowski, 1979). This study establishes baseline data on LaCygne Lake before it was used as a cooling pond and investigates initial changes in the zoo- plankton community of LaCygne Lake following electrical generation startup.

Seasonal succession and vertical distribution of zooplankton in Lake Hayes and Lake Johnson

Seasonal variations in the species composition, abundance, biomass, and vertical distribution of zooplankton in two eutrophic, warm‐monomictic lakes are described for the period December 1969 to February 1972. In Lake Hayes, Boeckella dilatata was the dominant crustacean and Ceriodaphnia dubia was subdominant. Lake Johnson was dominated by Ceriodaphnia and Bosmina meridionalis and Boeckella were subdominant. Daphnia were common in spring in Lake Hayes, but very rare in Lake Johnson. Chydorus and Asplanchna appeared in summer in both lakes. Zooplankton were slightly more abundant in both lakes in 1971 than in 1970; the annual mean was 1.7 times higher in Lake Johnson than in Lake Hayes in both years. Biomass was highest in spring. In Lake Hayes it ranged from 0.7 to 4.6 g.m‐2 dry weight; in Lake Johnson it fluctuated in 1971 from 0.3 g.m‐2 in March to 7.4 g.m‐2 in November. Animals occurred at all depths during holomixis, but were nearer the surface during stratification. Vertical distribution was often bi...

Der Einfluss experimentell variierter Zooplanktondichte auf die Produktion und Sedimentation im hocheutrophen See

Size-selective enrichment or exclusion of planktonic crustaceans significantly alters the succession of phytoplankton and smaller zooplankton. The cell density of algae (particularly of smaller forms) and the rate of production (life expectancy) of zooplankton increase sharply in the test units poor in zooplankton. In this primary production phase, the phosphate content of the water decreases within 10 days to 5%, of its original value. Large herbivorous populations reduce the sedimentation rate of the organic substance, while increasing the P:C ratio of the sediment.

First observations on longitudinal succession of Zooplankton in the main course of the Paraná River between Santa Fe and Buenos Aires Harbour

Summary The material was been collected in 1972 during a field trip performed by the research vessel of the National Institute of Limnology, Argentina, along the main course of the Parana River from the Santa Fe harbor down to the Rio de la Plata. Sixty sampling stations were covered. In the lower course of the river sampling was carried out in the Parana Guazu and the Parana Bravo branches down to its confluence with the Uruguay River, and the Parana de las Palmas and the Rio de la Plata down to the Buenos Aires harbor. Water samples for chemical analysis were collected and some physical parameters were measured. Due to the characteristics of the part of the river under consideration, we have divided it into four sectors. Sixty six species were seen. The rotifers were always the most important. Trichocerca rattus was the predominant species. The Zooplankton density and specific diversity showing differences between those from industrialized areas and not industrialized ones.