Source of organic matter in the sinking particles collected from the Pacific Sector of the Antarctic Ocean by sediment trap experiment

• Main Authors: Hidekazu Matsueda, Nobuhiko Handa
• Format: Report
• Language: English
• Published: Water Research Institute, Nagoya University 1986
• Subjects: Antarctic; Antarctic Ocean; Pacific; The Antarctic; Antarc*; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1907; http://id.nii.ac.jp/1291/00001907/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1907&item_no=1&attribute_id=18&file_no=1

Sediment trap experiment was conducted at Stn. 3 (61°34.1′S, 150°23.3′E) in the Pacific Sector of the Antarctic Ocean for 23 days from December 20,1983 to January 13,1984. Sinking particles from 630,1430 and 3230m depths, suspended particles from 1,30,80 and 500m depths and bottom sediment were analyzed for hydrocarbons, which consisted of n-alkanes with the carbon atoms ranging from 14 to 32 (n-alkane, n-C_<14>-C_<32>), heneicosahexaene (n-C_<21 : 6>), isoprenoid hydrocarbons and branched C_<25> and cyclic C_<30> alkenes (br-C_<25> and c-C_<30>). Hydrocarbons were quantified by gas chromatography and identified and/or elucidated by combined gas chromatography and mass spectrometry. Isoprenoid hydrocarbons consisted of squalene, pristane and phytane, while branched C_<25> and C_<30> alkenes were composed of br-C_<25 : 3>, br-C_<25 : 4>, br-C_<25 : 3'> (isomer of br-C_<25 : 3>), c-C_<30 : 4 : 1> and c-C_<30 : 4 : 2>. Hydrocarbon composition was characteristic to each of the particle and sediment samples. Thus, the hydrocarbon composition gives us a clue to clarify the source of organic matter in the sinking particles collected from the intermediate and deep waters. Heneicosahexaene widely occurring in diatoms and coccolithophores, was found in the suspended and sinking particles, indicating that organic matter in the sinking particles was derived from diatoms and/or coccolithophores living in the surface waters. br-C_<25> and C_<30> alkenes commonly found in the fecal pellets, were abundant in the sinking particles collected from the intermediate through deep waters. Thus, these findings indicate that large part of the organic materials in the sinking particles are derived from phytoplankton growing in the surface waters through fecal pellets of zooplankton. Occurrence of br-C_<25> and C_<30> alkenes even in the suspended particles of the euphotic layers indicates that these particles are contaminated ...