Abstract
The Shiretoko is a pennusla where a unique interaction occurs between the terrestrial and oceanic systems, which are linked by nutrient exchange processes. Nutrient rich floating sea ice is transported to the coast from the Okhotsk Sea and salmon and trout move upstream and feed inland animals, such as bears and birds. Conversely, nutrients flow into the ocean through rivers. It has been reported that this unique nutrient circulation is being disrupted by climate change and it is thus important to understand what mechanisms drive nutrient circulation in Shiretoko and maintain a unique ecological system. In this study, stable isotope analysis is used in combination to determine the contribution of land-derived (LDN) and marine-derived nutrients (MDN) in the Rausu River basin. Stable isotopes ratios, δ13C and δ15N, show a higher contribution of MDN before the snow-melt floods, and that MDN are distributed largely in the downstream region of the basin.
