Particle sources and downward fluxes in the Eastern Fram Strait under the influence of the West Spitsbergen Current

• Published in: Deep Sea Research Part I: Oceanographic Research Papers
• Main Authors: Sanchez-Vidal, Anna, Veres, Oriol, Langone, Leonardo, Ferré, Benedicte, Calafat Frau, Antoni, Canals Artigas, Miquel, Durrieu de Madron, Xavier, Heussner, Serge, Mienert, Jürgen, Grimalt Obrador, Joan, Pusceddu, Antonio, Danovaro, Roberto
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Ltd 2015
• Subjects: Geotècnia marina; Marine geotechnics; Arctic; Arctic Ocean; Storfjordrenna; Fram Strait; Phytoplankton; Sea ice; Spitsbergen
• Online Access: http://hdl.handle.net/2445/127765

The carbon cycle of the Arctic Ocean is tightly regulated by land-atmosphere-cryosphere-ocean interactions. Characterizing these environmental exchanges and feedbacks is critical to facilitate projections of the carbon cycle under changing climate conditions. The environmental drivers of sinking particles including organic carbon (OC) to the deep-sea floor are investigated with four moorings including sediment traps and currentmeters at the Arctic gateway in the eastern Fram Strait, which is the area where warm anomalies are transported northwards to the Arctic. Particles fluxes were collected over one year (July 2010-July 2011) and have been analysed to obtain the content of the lithogenic fraction, calcium carbonate, OC and its stable isotopes, opal, and the grain size. Records of near bottom current speed and temperature along with satellite observations of sea ice extent and chlorophyll-a concentration have been used for evaluation of the environmental conditions. We found increased lithogenic fluxes (up to 9872 mg m−2 d−1) and coarsening grain size of settling particles in late winter-early spring. At the same time, intensifications of the northward flowing west Spitsbergen current (WSC) were recorded. The WSC was able to resuspend and transport northwards sediments that were deposited at the outlet of Storfjordrenna and on the upper slope west of Spitsbergen. The signal of recurrent winnowing of fine particles was also detected in the top layer of surface sediments. In addition, an increased arrival of sea ice transported ice rafted detritus (>414 detrital carbonate mineral grains larger than 1 mm per m2) from the southern Spitsbergen coast along with terrestrial organic matter was observed beyond 1000 m of water depth during winter months. Finally, the downward particle fluxes showed typical temporal variability of high latitudes, with high percentages of the biogenic compounds (opal, organic carbon and calcium carbonate) linked to the phytoplankton bloom in spring-summer. However, on an annual basis ...