Millenial-scale sclerochronology of coralline red algae for reconstructing sea surface temperatures of extratropical seas

Giant coralline red algae (Clathromorphum nereostratum) were collected during our research cruise to the Bering Sea in Summer 2008. This specimen has lived for more than 1000 years.

The quantitative evaluation of the human impact on climate and ecosystems and predictions of future climate evolution require knowledge of past climates and the use of climate models. In order to calibrate climate models, currently unavailable high-resolution and long-term records of environmental variables from key localities along the northwestern Atlantic, the northern Pacific and the Arctic ocean are desperately needed. So-called proxy climate data, derived from skeletons of long-lived marine organisms can complement and significantly extend such records in space and time. Skeletons of these organisms are laid down in the form of growth increments, very similar to tree rings in the terrestrial realm. Analyses of growth and geochemical data archived in the calcified growth increments allow reconstructions of past climates. Our research is currently focused on deciphering paleoclimates of the past centuries and millenia from crustose coralline red algae– a recently discovered environmental archive that is providing data from regions where currently no other marine proxy information is available. Our work has contributed to a better understanding of higher frequency climatic phenomena, such as the Pacific Decadal Oscillation (PDO), El Nino Southern Oscillation (ENSO), and North Atlantic Oscillation (NAO) – climate patterns that exert a large-scale influence on the Northern Hemisphere and are responsible for dramatic changes in productivity of marine and terrestrial ecosystems. Furthermore, we have recently discovered the use of coralline algae in reconstruction long-term changes in Arctic sea ice at annual resolution. See details of coralline algal subprojects on previous page.