Microzooplankton dominate carbon flow and nutrient cycling in a warm subtropical freshwater lake

Hambright, K. David; Zohary, Tamar; Güde, Hans

doi:10.4319/lo.2007.52.3.1018

Cited by 42 publications

(33 citation statements)

References 47 publications

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“…Interestingly, the smaller microzooplankton have a significant overall impact shaping the food web structure in the model simulations despite having the lowest biomass. These findings are in line with the empirical studies of Hart et al (2000) and Hambright et al (2007), who highlighted the critical role of small micrograzers in the microbial loop processes. Since there exists a range of uncertainty surrounding the parameterisation of microzooplankton excretion, with large ranges being reported (Fasham et al, 1999;Faure et al, 2010), correct model parameterisation remains an important challenge for modellers.…”

Section: Role Of the Microbial Loop In Regulating Nutrient Flowssupporting

confidence: 91%

“…The latter refers to the dynamics of the heterotrophic bacteria and the microzooplankton grazers (defined here as size less than 125 µm that account for rotifers, ciliates and juvenile macrograzers; Thatcher et al, 1993) -often termed the "microbial loop". This has been shown to play an important role in shaping carbon fluxes in lakes and in enhancing nutrient cycling at the base of food webs (Gaedke et al, 2002), including in Lake Kinneret which is the focus in this study (Stone et al, 1993;Hart et al, 2000;Hambright et al, 2007;Berman et al, 2010).…”

Section: Y LI Et Al: Microbial Loop Effects On Lake Stoichiometrymentioning

confidence: 98%

“…For simplicity, microzooplankton are considered to graze on either bacteria or detritus, since the rate of grazing on small size phytoplankton (A 4 ) has been reported to be relatively low compared to the rate of bacterial grazing (∼ 10 % of total microzooplankton diet in Lake Kinneret; Hambright et al, 2007).…”

Section: Micrograzer Grazingmentioning

confidence: 99%

“…It is well established that microzooplankton can transfer energy and nutrients via bacterial grazing to higher trophic levels due to their small size and high mass-specific grazing rates (Hart et al, 2000;Loladze et al, 2000), thereby playing an important role in carbon and nutrient recycling (Stone et al, 1993;Dolan, 1997;Hambright et al, 2007). In turn, larger zooplankton grazing on microzooplankton further provide organic matter for bacterial growth through excretion of nutrient rich organic compounds (DOM) and fecal pellet production (POM) (Peduzzi and Herndl, 1992).…”

Section: Role Of the Microbial Loop In Regulating Nutrient Flowsmentioning

confidence: 99%

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Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

et al. 2014

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Abstract. The recycling of organic material through bacteria and microzooplankton to higher trophic levels, known as the "microbial loop", is an important process in aquatic ecosystems. Here the significance of the microbial loop in influencing nutrient supply to phytoplankton has been investigated in Lake Kinneret (Israel) using a coupled hydrodynamicecosystem model. The model was designed to simulate the dynamic cycling of carbon, nitrogen and phosphorus through bacteria, phytoplankton and zooplankton functional groups, with each pool having unique C : N : P dynamics. Three microbial loop sub-model configurations were used to isolate mechanisms by which the microbial loop could influence phytoplankton biomass, considering (i) the role of bacterial mineralisation, (ii) the effect of micrograzer excretion, and (iii) bacterial ability to compete for dissolved inorganic nutrients. The nutrient flux pathways between the abiotic pools and biotic groups and the patterns of biomass and nutrient limitation of the different phytoplankton groups were quantified for the different model configurations. Considerable variation in phytoplankton biomass and dissolved organic matter demonstrated the sensitivity of predictions to assumptions about microbial loop operation and the specific mechanisms by which phytoplankton growth was affected. Comparison of the simulations identified that the microbial loop most significantly altered phytoplankton growth by periodically amplifying internal phosphorus limitation due to bacterial competition for phosphate to satisfy their own stoichiometric requirements. Importantly, each configuration led to a unique prediction of the overall community composition, and we conclude that the microbial loop plays an important role in nutrient recycling by regulating not only the quantity, but also the stoichiometry of available N and P that is available to primary producers. The results demonstrate how commonly employed simplifying assumptions about model structure can lead to large uncertainty in phytoplankton community predictions and highlight the need for aquatic ecosystem models to carefully resolve the variable stoichiometry dynamics of microbial interactions.

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Section: Role Of the Microbial Loop In Regulating Nutrient Flowssupporting

confidence: 91%

Section: Y LI Et Al: Microbial Loop Effects On Lake Stoichiometrymentioning

confidence: 98%

Section: Micrograzer Grazingmentioning

confidence: 99%

Section: Role Of the Microbial Loop In Regulating Nutrient Flowsmentioning

confidence: 99%

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Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

et al. 2014

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“…Because C, C a , and M do not apply to our mesocosm experiment, we used the median values for these parameters, given in table 2 of Peters and Downing (1984). Although there has been much research on zooplankton grazing rates since the publication of Peters and Downing (1984), recent studies show that this equation adequately estimates clearance rates (Tirok and Gaedke 2006), even for rotifers (Hambright et al 2007). On each date on which zooplankton were enumerated, we calculated a mean clearance rate (mL individual 21 d 21 ) for each zooplankton taxon in each mesocosm, and multiplied this by population density (individuals L 21 ) to obtain population clearance rate (mL L 21 d 21 ).…”

Section: Methodsmentioning

confidence: 99%

Phytoplankton communities and stoichiometry are interactively affected by light, nutrients, and fish

Mette

Vanni

Newell

et al. 2011

Limnology & Oceanography

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We examined the separate and interactive effects of light, nutrients, and zooplanktivorous fish on phytoplankton nutrient stoichiometry, taxonomic richness, community composition, and the associations among these variables. We manipulated light supply, nutrient supply, and zooplanktivorous fish (presence or absence), in a factorial design using mesocosms containing regional phytoplankton and zooplankton assemblages. C : N and C : P were highest under high nutrients and high light. We observed interactive effects on the relative abundance of major phytoplankton taxa. Chlorophytes were most abundant in the majority of the treatments, although cyanobacteria dominated under high light, low nutrients, and with fish present. Cryptomonads were rare in all but the low-light, high-nutrient treatment. Relative abundance of diatoms was negatively affected by light, but only in the presence of fish. Chlorophyte relative abundance (% chlorophytes) was positively correlated with seston C : P, while relative abundances of diatoms and cryptomonads were negatively correlated with C : P. Phytoplankton taxon richness was positively associated with both % chlorophytes and seston C : P, and the number of chlorophyte taxa increased disproportionately with total taxon richness. Assemblage-level stoichiometric responses may be driven not only by direct responses to resource supply ratios, but also by algal community response. In particular, factors that increase taxonomic richness and both the richness and biomass of chlorophytes also result in increased seston C : P. Our results suggest strong feedbacks between phytoplankton community composition and stoichiometry, induced by interactive effects of light, nutrients, and predators.

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Bottom‐up linkages between primary production, zooplankton, and fish in a shallow, hypereutrophic lake

Matsuzaki

Suzuki

Kadoya

et al. 2018

Ecology

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Nutrient supply is a key bottom-up control of phytoplankton primary production in lake ecosystems. Top-down control via grazing pressure by zooplankton also constrains primary production and primary production may simultaneously affect zooplankton. Few studies have addressed these bidirectional interactions. We used convergent cross-mapping (CCM), a numerical test of causal associations, to quantify the presence and direction of the causal relationships among environmental variables (light availability, surface water temperature, NO -N, and PO -P), phytoplankton community composition, primary production, and the abundances of five functional zooplankton groups (large cladocerans, small cladocerans, rotifers, calanoids, and cyclopoids) in Lake Kasumigaura, a shallow, hypereutrophic lake in Japan. CCM suggested that primary production was causally influenced by NO -N and phytoplankton community composition; there was no detectable evidence of a causal effect of zooplankton on primary production. Our results also suggest that rotifers and cyclopoids were forced by primary production, and cyclopoids were further influenced by rotifers. However, our CCM suggested that primary production was weakly influenced by rotifers (i.e., bidirectional interaction). These findings may suggest complex linkages between nutrients, primary production, and rotifers and cyclopoids, a pattern that has not been previously detected or has been neglected. We used linear regression analysis to examine the relationships between the zooplankton community and pond smelt (Hypomesus nipponensis), the most abundant planktivore and the most important commercial fish species in Lake Kasumigaura. The relative abundance of pond smelt was significantly and positively correlated with the abundances of rotifers and cyclopoids, which were causally influenced by primary production. This finding suggests that bottom-up linkages between nutrient, primary production, and zooplankton abundance might be a key mechanism supporting high planktivore abundance in eutrophic lakes. Because increases in primary production and cyanobacteria blooms are likely to occur simultaneously in hypereutrophic lakes, our study highlights the need for ecosystem management to resolve the conflict between good water quality and high fishery production.

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Microzooplankton dominate carbon flow and nutrient cycling in a warm subtropical freshwater lake

Cited by 42 publications

References 47 publications

Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics

Phytoplankton communities and stoichiometry are interactively affected by light, nutrients, and fish

Bottom‐up linkages between primary production, zooplankton, and fish in a shallow, hypereutrophic lake

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