Biochemical Characteristics of Suspended Particulate Matter on a Latitudinal Transect in the North Atlantic

Abstract

Dispersed sedimentary matter was studied along the latitudinal transect 59°30′ N from Great Britain to Greenland on cruise 49 of the R/V Akademik Ioffe in June 2015. The concentrations of suspended particulate matter (SPM) along the transect were low, increasing from 0.24 to 1.07 mg/L in the surface layer (0–5 m), from 0.24 to 0.99 mg/L in the pycnocline (thermocline) zone, and appreciably decreasing toward the bottom layer, fluctuating from 0.10 to 0.56 mg/L. The isotopic composition of organic carbon in SPM was determined in 18 samples. The δ¹³C-C_org values vary from –17 to –24.6‰. Judging from the chlorophyll a content, the isotopic composition of water masses, and their remoteness from the coast, the carbon in SPM is mainly represented by autochthonous organic matter of phytoplanktonic origin. The presence of SPM with a heavy isotopic composition in the surface layer of the water column can serve as evidence for the current processes of phytoplankton bloom. In this case, differences in the intensity of these processes can be observed, creating a mosaic bloom pattern even within a distance of 150 NM.