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Hydrodynamic habitat influences suspension feeding by unionid mussels in freshwater ecosystems
Author(s) -
Byllaardt Julie,
Ackerman Josef D.
Publication year - 2014
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.12339
Subject(s) - river ecosystem , seston , ecology , lake ecosystem , habitat , mussel , freshwater ecosystem , biology , benthic zone , aquatic ecosystem , clearance rate , ecosystem , invertebrate , phytoplankton , nutrient , endocrinology
SummaryBenthic suspension feeders play significant roles in aquatic ecosystems, but the influences of abiotic, especially hydrodynamic, factors on many of their activities remain largely unknown. This is especially true for freshwater unionid mussels, which are important inhabitants of rivers and lakes, often forming multispecies assemblages in the former. Our goal is to determine whether and how seston flux affects the suspension feeding of freshwater unionid mussels from different hydrodynamic habitats (i.e. lentic and lotic). Fluorometric measurements of algal depletion in a recirculating flow chamber were used to determine the clearance rate ( CR ) of four freshwater mussel species: E lliptio complanata , E lliptio dilatata , F usconaia flava and S trophitus undulatus . Clearance rate varied with algal flux ( J = UC , where U is velocity and C is algal concentration) for all species examined, resulting in a 41‐fold increase in CR for some species , compared with no‐flux controls. Importantly, the results from the no‐flux controls were consistent with published CR values obtained under static conditions.E lliptio dilatata from the fastest flowing lotic system (Grand River, Ontario) cleared up to four times more algae than any other species, including its conspecifics from a slower flowing river (Ausable River, Ontario) and the species from the lentic habitat ( E . complanata; Lake Opeongo, Ontario). Differences in CR s were also found among E . dilatata, F . flava and S . undulatus from the same lotic habitat at the highest algal flux examined, indicating that species may specialise to different hydrodynamic conditions. The impact of suspension feeding by unionid mussels has probably been underestimated, especially under lotic conditions with high seston flux. Mussels may have ecotypic responses to their hydrodynamic habitats, which affect their CR . Moreover, specialisation within a single habitat type is indicative of resource partitioning that could reduce competition in multispecies assemblages.