Does the Antarctic Circumpolar Current isolate high-latitude bivalves from ENSO forcing?

BREY T.,; LOHMANN G.,; JENKINS K.,; AHN I.Y.,; BETINA JUDITH LOMOVASKY; VOIGT M.,

Mainz

Congreso; 2nd International Sclerochronology Conference; 2010

The Antarctic Circumpolar Current (ACC) is called the “mightiest current in the oceans” (±125 Sverdrup) and represents a distinct barrier between sub-Antarctic (no winter sea ice, summer SST > 5°C)  and truly Antarctic environments (winter sea ice, summer SST < 5°C). We present data on decadal shell growth patterns over the last 50 years in shallow water bivalve species from either side of the ACC, i.e. Euthomalea exalbida from the Beagle Channel, Tierra del Fuego, South America (54º50´S, 68º16´W), and Laternula ellipica from King George Island, South Shetland Islands, Antarctica (62°14´ S 58°31´W). In both species, shell growth is coupled to El Niño Southern Oscillation (ENSO). ENSO forcing differs between the two species in its dominant frequency mode and in sign and may even change over time. We discuss ENSO signal transmission pathways and forcing mechanisms with particular reference to ongoing climate change in the Antarctic Peninsula region.Euthomalea exalbida from the Beagle Channel, Tierra del Fuego, South America (54º50´S, 68º16´W), and Laternula ellipica from King George Island, South Shetland Islands, Antarctica (62°14´ S 58°31´W). In both species, shell growth is coupled to El Niño Southern Oscillation (ENSO). ENSO forcing differs between the two species in its dominant frequency mode and in sign and may even change over time. We discuss ENSO signal transmission pathways and forcing mechanisms with particular reference to ongoing climate change in the Antarctic Peninsula region.