Benthic invertebrate activity in lakes: linking present and historical bioturbation patterns

Trace fossils of lacustrine benthos are less well known than those of marine benthos, limiting their potential use in interpreting paleo-environmental conditions, including climate change, reconstructing lake ecosystems, and predicting effects of sediment mixing of paleoclimate records. Here, we present a synopsis of limnological controls on the distribution of present day lacustrine benthos, a synopsis of their burrowing and feeding habits, and a summary of the traces they produce. Maximum diversity and density of benthos occur in sublittoral zones and decrease both shoreward and basinward. Common taxa include bivalves (unionids, sphaeriids), snails, oligochaetes, amphipods, and insects (particularly chironomids and ephemeropterans). With a few exceptions, traces produced are morphologically simple, shallowly inscribed, and have low preservation potential. Although lacustrine benthic organisms are widespread, variability within and between lakes causes them and their traces to be patchily distributed. To truly understand the records left in lacustrine sediments and the links between modern and ancient traces, we need comprehensive surveys over a range of lake types and collaborations between ichnologists and benthic ecologists.