Comprehensive study of the Caspian Sea in voyage 32 of R/V Rift

Abstract

704 Systematic investigation of the Caspian Sea in 2009 was conducted in accordance with the Programs of the Presidium of the Russian Academy of Sciences no. 17.1. "System Explorations of the Seas of the European part of Russia" (head, Academician of the Russian Acad� emy of Sciences A.P. Lisitsyn) and no. 17.2 "Inte� grated Studies in the Caspian Sea" (head, Corre� sponding Member of the Russian Academy of Sci� ences L.I. Lobkovskii). Voyage 32 was conducted from September 7 to 16, 2009. The main task of the voyage was to obtain infor� mation on the Transcaspian section for a comprehen� sive study of processes in the system of the Caspian Sea. We measured hydrophysical (CTDand ADCP� sounding, measurements of currents and temperature on submerged buoy stations) and hydrooptical (mea� suring the attenuation of light, the brightness of the rising light, and other subsatellite measurements) characteristics. We sampled aerosols with the help of network method, seawater for hydrochemical studies, and filtering suspensions, as well as samples of depos� ited material from sediment traps. Onboard the vessel, we determined the hydrochemical parameters O 2 , Si, and PO4 pigments of chlorophyll "a" and pheophytin using a Trilogy Fluorometer (mod. 7200�000) and studied the size range of suspension using a Coulter Multisizer 3 counter. One of the highpriority tasks of the expedition was setting up submerged buoy stations (SBSs) with sediment traps and PotokM current meters (3). During the voyage, we conducted constant profile shooting of the bottom using Sparker and SES� 2000 seismoacoustic narrowradial parametric profil� ers and selected bottom sediments. The route of the expedition and the scheme of recovery and staging sta� tions are shown in Fig. 1. The results of CTDsounding (Indronaut Ocean 316) showed that the hydrological structure of the water column of the Caspian Sea during that period was typ� ical for the transition of the summer-autumn season.