Zooplankton Grazing in a Potomac River Cyanobacteria Bloom

Sellner, Kevin G.; Brownlee, David C.; Bundy, M. H.; Brownlee, S. G.; Braun, K. R.

doi:10.2307/1352445

Cited by 54 publications

(24 citation statements)

References 28 publications

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“…mechanisms (Hutchinson 1961). Although grazing by predators, including zooplankton and fish, contributes to changes in phytoplankton communities, spatiotemporal fluctuations of such communities are caused primarily by changes in abiotic variables (Sellner et al 1993). Of these, high-velocity water flow (as a result of heavy precipitation or the discharge of dams) has been found to result in major shifts in the abundances and compositions of phytoplankton assemblages (Hallegraeff 1993).…”

Section: Sample Collection and Analysismentioning

confidence: 99%

Impacts of dam discharge on river environments and phytoplankton communities in a regulated river system, the lower Han River of South Korea

Jung¹,

Kwon²,

Yun³

et al. 2014

J. Ecol. Environ.

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To understand the effects of fluctuations in dam discharge due to river environments and phytoplankton communities, we monitored such environments and phytoplankton communities biweekly, from February 2001 to February 2002 and from February 2004 to February 2005, in the lower Han River (LHR), South Korea. The phytoplankton abundance during the dry season was approximately two times higher than that during the rainy season. In particular, fluctuations in diatom assemblages, which constituted over 70% of the total phytoplankton abundance, were affected severely by the changes in the discharge. When a large quantity of water in a dam was discharged into the LHR, the conductivity and the concentrations of total nitrogen (TN), total phosphorus (TP), and dissolved inorganic phosphorus (DIP) decreased rapidly, whereas the concentrations of suspended solids (SS), dissolved inorganic nitrogen (DIN), and dissolved silica (DSi) increased immediately. Time-delayed relationship also revealed that the dam discharge had an immediately significant negative relationship with phytoplankton abundance. On the whole, fluctuations in phytoplankton communities in the LHR were influenced much more by hydrodynamics such as dam discharge than by the availability of nutrients. Thus, the variability in these concentrations usually parallels the strength of river flow that is associated with summer rainfall, with higher values during periods of high river discharge.

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Section: Sample Collection and Analysismentioning

confidence: 99%

Impacts of dam discharge on river environments and phytoplankton communities in a regulated river system, the lower Han River of South Korea

Jung¹,

Kwon²,

Yun³

et al. 2014

J. Ecol. Environ.

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“…Heerkloss et al (1984) estimated assimilation efficiencies of 50 to 80% for A. tonsa when they fed on the cyanobacteria Microcystis areuginosa, while an assimilation efficiency of 35% was found when they fed on the cyanobacteria Oscillatoria redeckii. Field studies have shown low grazing on filamentous cyanobacteria by copepods and cladocerans during bloom conditions in temperate estuarine or brackish waters (Sellner et al 1993(Sellner et al , 1994(Sellner et al , 1996. This result contrasts with that found for zooplankton feeding on cyanobacteria in frkshwater environments (see above).…”

Section: Introductionmentioning

confidence: 76%

Food selection by calanoid copepods in the euphotic layer of the Gotland Sea (Baltic Proper) during mass occurrence of N2-fixing cyanobacteria

Meyer¹,

Reckermann²,

Voß³

et al. 1999

Mar. Ecol. Prog. Ser.

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Food selection by 2 dominant calanoid copepods, Acartia sp. and Temora longicornis, was studied during mass occurrence of N2-fixing cyanobacteria in June/July 1993 and 1994 in the Gotland Sea (Baltic Proper). The aim of this study was to assess the importance of Nz-f~xing cyanobacteria in the diet of calanoid copepods. Two different methods were used: firstly the analysis of marker carotenoids by HPLC (high-performance liquid chromatography), and secondly the analysis of 615N signals of copepods by mass spectrometry. The first method provides a 'snapshot' of autotrophic material ingested; the second method summarises a longer period, and gives evidence that a certain food source is not only ingested but also assimilated. In 1994, mass occurrence of cyanobacteria showed a higher concentration in the e.uphotic layer than 1993 (97 1-19 C 1. ' In 1994, 57 pg C 1. ' in 19931, which was reflected in higher food uptake of N2-fixing cyanobacteria in 1994. The average relative amount of myxoxanthophyll, the specific carotenoid of NZ-fixing cyanobacteria, in the copepod guts showed high values in 1994 (Acartia sp. 3?%, T. longicornis 41961 and low values in 1993 (1 % for both copepods). The low SI5N values of both Acartia sp. and T longicornis in 1994 (9%) compared to those in 1993 (10.5%0) support the results of HPLC analyses, because NZ-fixing cyanobacteria have a lower 6I5N (average 0.7%0) than eukaryotic phytoplankton (average 12Yk). The low 6I5N values in 1994 indlcate that NZ-futing cyanobacteria were not only ingested but also assirmlated by the copepods to a higher extent in 1994 than 1993.

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“…Microalgal species composition and abundance are intimately linked to higher trophic levels through preferential grazing by herbivores (zooplankton, suspension feeders, deposit feeders) (98)(99)(100)(101). The implication for food webs is that some phytoplankton blooms may be ungrazed and deposited in surficial sediments, providing labile carbon substrates for benthic respiration, hypoxia, and anoxia following large blooms.…”

Section: Consequences Of Eutrophicationmentioning

confidence: 99%

The role of nutrient loading and eutrophication in estuarine ecology.

Pinckney

Paerl

Tester

et al. 2001

Environ Health Perspect

139

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Eutrophication is a process that can be defined as an increase in the rate of supply of organic matter (OM) to an ecosystem. We provide a general overview of the major features driving estuarine eutrophication and outline some of the consequences of that process. The main chemical constituent of OM is carbon (C), and therefore rates of eutrophication are expressed in units of C per area per unit time. OM occurs in both particulate and dissolved forms. Allochthonous OM originates outside the estuary, whereas autochthonous OM is generated within the system, mostly by primary producers or by benthic regeneration of OM. The supply rates of limiting nutrients regulate phytoplankton productivity that contributes to inputs of autochthonous OM. The trophic status of an estuary is often based on eutrophication rates and can be categorized as oligotrophic (<100 g C m(-2) y(-1), mesotrophic (100-300 g C m(-2) y(-1), eutrophic (300-500 g C m(-2) y(-1), or hypertrophic (>500 g C m(-2) y(-1). Ecosystem responses to eutrophication depend on both export rates (flushing, microbially mediated losses through respiration, and denitrification) and recycling/regeneration rates within the estuary. The mitigation of the effects of eutrophication involves the regulation of inorganic nutrient (primarily N and P) inputs into receiving waters. Appropriately scaled and parameterized nutrient and hydrologic controls are the only realistic options for controlling phytoplankton blooms, algal toxicity, and other symptoms of eutrophication in estuarine ecosystems.

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Zooplankton Grazing in a Potomac River Cyanobacteria Bloom

Cited by 54 publications

References 28 publications

Impacts of dam discharge on river environments and phytoplankton communities in a regulated river system, the lower Han River of South Korea

Impacts of dam discharge on river environments and phytoplankton communities in a regulated river system, the lower Han River of South Korea

Food selection by calanoid copepods in the euphotic layer of the Gotland Sea (Baltic Proper) during mass occurrence of N2-fixing cyanobacteria

The role of nutrient loading and eutrophication in estuarine ecology.

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