Benthic food webs

In addition to its broad occurrence under contrasting conditions, easy collection, relatively long life span, and resistance to the accumulation of toxic chemicals, zebra mussels provide a link between the pelagic and benthic food webs, possibly creating a rapid pathway for contaminant transfer from sediments to predators such as common carp (Cyprinus carpio) and, occasionally, humans [32, 42—4-7]. Consequently, zebra mussel has been considered a potential sentinel organism for assessing Hg redistribution from point sources in the Ebro River and the degree of bioavailability to river and wetland food webs. 

Benthic Food Web. In contrast to the planktonic community, there was a much smaller enrichment of 15N in plants and animals of the benthic food web. The moss Calliergon showed an enrichment in 15N up to about 10(/,o, which indicates that these plants are drawing fixed nitrogen directly from the water column (Table I natural-abundance 815N values of Calliergon are around l-2%o). Periphyton scraped from the control side of the curtain... 

Peterson, B. J. (1999). Stable isotopes as tracers of organic matter input and transfer in benthic food webs A review. Acta Oecologica 20(4), 479-487. 

The generally low d N of terrestrial systems is typically retained in sludge and particulate matter produced by sewage plants. Nitrogen isotopic studies in a number of coastal systems have demonstrated that this low d N propagates into the benthic food web and can be used to quantify the impact ofsoHd materials in sewage on the nearshore biota (Rau et al., 1981 Spies et al., 1989 Tucker et al., 1999 Van Dover et al., 1992). 

Vander Zanden MJ, Vadeboncoeur Y. 2002. Fishes as integrators of benthic and pelagic food webs in lakes. Ecology 83 2152-2161. 

The bioavailability of selenium to a benthic deposit-feeding bivalve, Macoma balthica from particulate and dissolved phases was determined from AE data. The selenium concentration in the animals collected from San Francisco Bay was very close to that predicted by a model based on the laboratory AE studies of radiolabelled selenium from both particulate and solute sources. Uptake was found to be largely derived from particulate material [93]. The selenium occurs as selenite in the dissolved phase, and is taken up linearly with concentration. However, the particle-associated selenium as organoselenium and even elemental selenium is accumulated at much higher levels. The efficiency of uptake from the sediment of particulate radiolabelled selenium was 22%. This contrasts with an absorption efficiency of ca. 86% of organoselenium when this was fed as diatoms - the major food source of the clam. The experiments demonstrated the importance of particles in the uptake of pollutants and their transfer through the food web to molluscs, but the mode of assimilation was not discussed. 

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