Photo: Fragilariopsis cylindrus, a diatom indicative of sea ice. BASBy Jan Strugnell, British Antarctic Survey

The last few days we have been searching for suitable coring sitesand coring for the geologists for the BAS CACHE-PEP-G program. This focus of this program is to investigate the last 10, 000 years of Earth history and specifically how the Antarctic climate has interacted with the global climate. The program uses ice cores, lake sediments and marine sediments to build up this picture.


Photo: Corethron criophilum, a diatom.

On this cruise, the geologists are trying to find marine sediments that have built up over the last 10,000 years. Marine sediments are built up over time from tiny photosynthetic algae, specifically siliceous diatoms. When these diatoms are alive they live in the surface layers of the world’s oceans. Different diatom assemblages thrive under different conditions of nutrients, temperature, light and ice conditions. When the diatoms die they sink to the sea floor and therefore this builds up a picture of past climatic conditions in the sediments. By taking a core of these sediments, the geologists are able to essentially look back through time and use the diatom assemblages as indicators of past conditions climatic changes.


Photo: Chaetoceros dichaete, a diatom indicative of high productivity. BAS

To date, there are no published records of these diatom assemblages from the entire Pacific area of the Southern Ocean! Therefore the aim of this part of the cruise is to obtain some cores from this region of Antarctica to get a better idea the climatic patterns in this area over the last 10,000 years. The geologists are using a piston corer to do this, and hope to obtain a number of 10-12 metre long cores of sediment from this region. The attached pictures are of siliceous marine diatoms. The presence of Fragilariopsis cylindrus is indicative of sea ice whilst the presence of Chaetoceros dichaete is indicative of high productivity.

From February 19th until April 10th 2008, British scientists are embarking on the British Antarctic Survey’s (BAS) research ship RRS James Clark Ross. This project is part of the BAS program known as BIOFLAME (Biodiversity, Function, Limits and Adaption from Molecules to Ecosystems). Scientists onboard are studying marine fauna from the ocean shelves and slopes from a little-known region, the Bellingshausen and Amundsen Seas. This is part of the Census of Antarctic Marine Life. Follow their route on the CAML-Cousteau Expedition tracking page.