Characteristics of bottom sediments in the Kievka Bay of the Japan Sea

Basic properties of bottom sediments, including organic carbon content, are determined to understand biogeochemical cycles in the marine environment. The samples were collected using a geological column sampler from the upper 10-centimeter layer of the sediments at the depth of 12.2–99.0 m in Kievka Bay in the 83 rd cruise of RV Academician M.A. Lavrentiev. The bottom sediments in Kievka Bay are distinguished by significant content of organic carbon, in the medium to high categories, and high levels of major nutrients in the organic fraction, such as nitrogen, phosphorus and potassium. Their particle-size composition corresponds mainly to sandy loams, with prevalence of silicon, aluminum and iron in the mineral skeleton that is similar to coastal soils. The content of organic carbon and total nitrogen in the bottom sediments of Kievka Bay correlates positively with the portion of physical clay fraction. The same analytical techniques used for both bottom sediments and coastal soils allow to consider the continental-ocean transition zone as a single system.