Interannual Variation of Settling Particles Reflects Upper‐Ocean Circulation in the Southern Chukchi Borderland, 2010‐2014

Abstract

AbstractTime series monitoring of hydrography and marine settling particles supplies a large amount of information regarding the marine lower‐trophic ecosystem with respect to the changing Arctic Ocean. To investigate the interannual relationship between the settling particles and hydrographic conditions of the western Arctic Ocean, bottom‐tethered sediment trap moorings were deployed at the Northwind Abyssal Plain (NAP) from October 2010 to September 2014 and at the Chukchi Abyssal Plain (CAP) from October 2012 to September 2013 to the east and west of the Chukchi Borderland. The settling particles at both stations contained a significant amount of lithogenic matter, with biogenic particles being a lateral advection of shelf materials from shelf to basin. The many peaks of settling particle fluxes at NAP in 2013–2014 corresponded to the hydrographic events of passing oceanic eddies over the station, in addition to seasonal biological production. The settling particle flux at CAP remarkably increased when Pacific‐origin water advected over the northern shelf of the Chukchi Sea in March–April 2013. Additionally, abundant gelatinous matter was found at NAP and CAP in July–September 2011 and 2014 and in July–August 2013, respectively. The settling flux data of particulate organic matter and the mole ratio and stable isotope ratios of particulate organic carbon and nitrogen reflected the changes in the composition of trapped plankton assemblages under various hydrographic conditions over the course of the four years of the study.