Assimilation of micro‐ and mesozooplankton by zebra mussels: A demonstration of thefood web link between zooplankton and benthic suspension feeders

Abstract

We tested the hypothesis that rotifer species in the micro‐ and mesozooplankton are a potential food source for zebra mussels. We labeled phytoplankton with 14C, fed them to two species of rotifers (140–210 µm length) that were previously found abundantly in the Hudson River and had declined following a zebra mussel invasion, and estimated the assimilation of carbon. Assimilation efficiencies were found to be ~37.47–54.0%. Combined with our feeding experiments, the data on rotifer densities before and after the invasion allowed us to calculate the energy budgets for zebra mussels. Before zebra mussels dominated the Hudson River in 1992, the absorption of energy from rotifers was about two to three times higher than that necessary to maintain its routine metabolic rate and contributed about 0.349–0.662 J h−1 to mussel growth and reproduction, conferring a positive scope for growth. Since the zebra mussels became abundant in the Hudson River, assimilation of rotifers is still sufficient to explain ~16.4–23.1% of the mussels' routine metabolic rate. Therefore, rotifers play a conceivably large role in the energy budget of zebra mussels, whether at high rotifer concentrations (before the invasion) or at low rotifer concentrations (after the invasion). This is the first quantitative evidence for a trophic link between benthic bivalve mollusks and larger micro‐ and mesozooplankton that might extend to marine systems where bivalves can derive nutrition from microzooplankton, including planktonic invertebrate larvae. Combined with other recent results, this study documents a benthos‐zooplankton trophic loop, demonstrating potentially strong top‐down control by dense bivalves on aquatic systems.

Assimilation of carbon from a rotifer by the mussels Mytilus edulis and Perna viridis: a potential food-web link

“…Our results show that they are also a possible nutritional resource of bivalves, whether in freshwater or in the marine system, as demonstrated by studies on zebra mussels (Wong et al 2003) and the 2 marine species in this experiment.…”

“…210 µm long) and Lepadella ovalis (ca. 140 µm long) (Wong et al 2003). Our preliminary observations using video endoscopy suggest that rotifers can escape capture by mussel latero-frontal cilia, which might mean that retention of rotifers is inefficient.…”

“…In freshwater, it has been shown that the zebra mussel Dreissena polymorpha can capture and assimilate micro-and mesozooplanktonic rotifers, and that this food source can be an important part of the mussel's energy budget (Wong et al 2003). Despite the lack of quantitative estimates in marine systems, there is growing evidence to support the hypothesis that mesozooplankton is a potential food source for bivalves.…”

Grazing effects of blue mussel Mytilus edulis on the pelagic food web under different turbulence conditions

“…However, in summer and autumn, heterotrophic prey was more prominent and contributed 34 and 17% of mussel consumption during high and low turbulent conditions, respectively. Although the assimilation efficiency of heterotrophs is lower than for phytoplankton (Kreeger & Newell 1996, Wong & Twining 2003 Viitasalo et al (1998), are an important component of the natural diet of mussels, especially during periods with limited phytoplankton biomass, and should be taken into account in future investigations of mussel nutrition.…”

Recovery of native zooplankton associated with increased mortality of an invasive mussel

“…Similar declines occurred in some zooplankton groups (Pace et al 1998, Strayer et al 2008). Zebra mussels can collectively filter a large size-spectrum of particles ranging in size from bacteria (, 1 lm) to small zooplankton (MacIsaac et al 1995, Wong et al 2003. However, individual feeding ability varies with size.…”