Benthic diversity along an Arctic fjord: which are the key factors?

Abstract Arctic coastal ecosystems include benthic communities that hold an important role within the marine food chain. Kelps, fucoid species, and coralline algae dominate rocky habitats, offering food and shelter for various species. Kelps and fucoid species also aid in carbon sequestration, sediment stabilization, and erosion mitigation. In summer, the influx of freshwater from glacier and permafrost melt alters coastal waters conditions. The input of turbid freshwater influences underwater light, salinity, and substrate, impacting benthic organism distribution. This study investigates possible link between environmental conditions and benthic diversity through environmental DNA (eDNA). Six sites were monitored along Kongsfjorden (Svalbard,Norway) during the summer of 2021. Contrary to expectations, macroalgal distribution didn’t correlate with light, and suspension feeders showed no clear links with chlorophyll a or nutrient concentrations. Glacial influence may have contributed to higher benthic diversity. Predators’ presence, tied to glacier proximity, possibly explained this trend. However, further studies are needed to validate these observations and assumptions.