Intertidal Ostracoda from Fossvogur and Kópavogur bays (SW Iceland): Diversity and distribution

Abstract

Ostracods have been used in coastal monitoring as indicators of recent and past environmental changes due to their relatively high diversity, abundance and sensitivity. To assess the influence of salinity and potential human impacts on their diversity and distribution in two neighbouring bays in a growing urban area in SW Iceland, a set of 28 surface-sediment samples was collected at low tide in Fossvogur and Kópavogur. This first systematic record of intertidal ostracods in Iceland yielded a total of 16 taxa belonging to 10 families common to the Arctic and Temperate Northern Atlantic marine realms. The assemblages are dominated by Leptocythere castanea, Hemicythere villosa, Semicytherura nigrescens, Leptocythere lacertosa and Hirschmannia viridis. In general, lower diversity and abundance were recorded at engineered rocky shores as a result of coarser sediment at these locations, whilst L. lacertosa and Semicytherura sella show a marked preference for finer-grained substrates associated with more natural shores. Although inflows with lower salinity were not identified as a controlling factor of diversity and abundance in general, 85% of specimens of S. sella were found at locations influenced by inflows. Higher overall diversity was recorded at locations less exposed to the open sea where wave energy and currents are probably less significant. This study represents a missing reference for the spatial and temporal ostracod distribution in coastal ecosystems of Iceland in times of global change.