Líffræðifélag Íslands
Líffræðiráðstefnan 2015
Erindi/veggspjald / Talk/poster E11
Hrönn Egilsdóttir (1,2), Niall McGinty (3), Jón Ólafsson (1,2), Guðmundur Guðmundsson (4)
1. Department of Earth Sciences, University of Iceland, 2. Marine Research Institute, Iceland, 3. MARICE, University of Iceland, 4. Icelandic Institute of Natural History
Kynnir / Presenter: Hrönn Egilsdóttir
Tengiliður / Corresponding author: Hrönn Egilsdóttir (hre2@hi.is)
Ocean warming and ocean acidification have been identified as major threats to marine biodiversity worldwide, particularly in high latitude ecosystems. Ocean acidification comprises both a decrease in seawater pH and a decrease in the calcium carbonate saturation state (ΩCaCO3), an important environmental parameter for calcifying biota. As a result of low temperatures at high latitudes, the ΩCaCO3 is also naturally low in these areas. In addition, pressure has a negative effect on ΩCaCO3 so that the aragonite saturation horizon (i.e. the depth where seawater that is super-saturated with respect to aragonite meets under-saturated seawater) is relatively shallow at high latitudes. Currently, the aragonite saturation horizon is at ~1700 meter depth in the Iceland Sea and shoaling at a rate of at least 4 meters per year as a result of added CO2 dissolved in the ocean. Molluscs have been identified as among the most threatened phyla by ocean acidification and decreasing ΩCaCO3 as they often produce a shell made out of aragonite and sometimes also calcite. Along with other invertebrate phyla, benthic molluscs were sampled and identified during the BIOICE programme: a biodiversity assessment of the benthos within the Icelandic 200 mile economic zone. Sampling cruises 1992 to 2004, resulting in 1390 samples from 590 stations, spanning a depth of 20-3000 m. In this presentation we use BIOICE biodiversity data to describe and compare the depth distribution of major molluscan subgroups, bivalves, gastropods, chitons and tusk shells. We also analyse the species richness and biodiversity patterns of bivalves and gastropods and discuss the environmental parameters that are most likely to affect the diversity pattern. The work presented here can be considered as an important first step towards evaluating the degree to which the environmental changes described above, may affect benthic biodiversity in the Iceland Sea.