Seasonal dynamics of the Lake Kinneret food web:The importance of the microbial loop

Hart, Deborah R.; Stone, Lewi; Berman, T.

doi:10.4319/lo.2000.45.2.0350

Cited by 71 publications

(53 citation statements)

References 49 publications

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“…The apparently low percentage of actively metabolizing bacteria observed in Lake Kinneret throughout the year and at all water column depths was consistent with the results generated by a recent carbon flux model for Lake Kinneret (Hart et al 2000). In the published data for this model unrealistically high values for the ratios of bacterial biomass to production (B/P) were given, averaging 6.7, 3.4, 8.3 and 11.8 for spring, summer, fall and winter seasons respectively.…”

Section: Proportion Of 'Active' To 'Non-active' Bacteriasupporting

confidence: 76%

Metabolically active bacteria in Lake Kinneret

Berman¹,

Kaplan²,

Chava³

et al. 2001

Aquat. Microb. Ecol.

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Section: Proportion Of 'Active' To 'Non-active' Bacteriasupporting

confidence: 76%

Metabolically active bacteria in Lake Kinneret

Berman¹,

Kaplan²,

Chava³

et al. 2001

Aquat. Microb. Ecol.

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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: 79%

“…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: 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%

“…Initially, a steady-state C flux model was developed to examine C cycling through the planktonic biota, including consideration of the microbial loop (Stone et al, 1993;Hart et al, 2000). A one-dimensional (1-D) coupled hydrodynamic-ecosystem model (DYRESM-CAEDYM) was presented by Bruce et al (2006), which focused specifically on the zooplankton dynamics and their contribution to nutrient recycling.…”

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

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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Indices of water quality for sustainable management and conservation of an arid region lake, Lake Kinneret (Sea of Galilee), Israel

Hambright

Parparov

Berman

2000

Aquatic Conserv: Mar. Freshw. Ecosyst.

Self Cite

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1. Economic development in arid regions is closely linked to efficient use of limited water resources. As such, management and conservation of these water resources requires concurrent optimization of the interrelationships between supply quantity and resource quality.2. Multiple uses of water resources generate conflicting needs within management, with different uses requiring objective characterization of quality for different management scenarios and goals.3. A sound management programme needs close interactions between water policy makers, managers, users, engineers and limnologists, and thus needs a common language that can transcend the boundaries of the individual fields.4. This paper describes a system of water quality indices and standards designed for conservation and sustainable management of Lake Kinneret (Sea of Galilee), Israel, based on observed variability in various chemical and biological parameters during a 25-year period ). Such a system can form a common language which can then be used as a tool for optimal management. 5. This system of water quality indices (a) includes both traditional limnological parameters (plant nutrients, chlorophyll, primary production) and engineering parameters (coliform bacteria, turbidity), (b) is acceptable to all parties involved in lake management, and (c) is easily adaptable to different management scenarios and to management-induced changes in ecosystem functioning.6. Analysis of variability in these water quality parameters in Lake Kinneret during 1994 -1999 when the lake was showing signs of destabilization highlights the usefulness and limitations of this system.

show abstract

Seasonal dynamics of the Lake Kinneret food web:The importance of the microbial loop

Cited by 71 publications

References 49 publications

Metabolically active bacteria in Lake Kinneret

Metabolically active bacteria in Lake Kinneret

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

Indices of water quality for sustainable management and conservation of an arid region lake, Lake Kinneret (Sea of Galilee), Israel

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