DOC and POC in the water column of the southern Baltic. Part I. Evaluation of factors influencing sources, distribution and concentration dynamics of organic matter**This study was supported by the Baltic-C/BONUS Plus EUFP6 Project, statutory activities of Institute of Oceanology PAN, Sopot and the Polish Ministry of Science and Higher Education, grant No. N N306 404338.

• DOI: 10.5697/oc.55-3.523
• Publication Date: 2014-06-10T07:15:07Z
• Authors: Anna Maciejewska; Janusz Pempkowiak
• Keywords: Halocline; Biogeochemical Cycle

Organic substances are important components of the marine environment as they determine properties seawater and key biogeochemical processes taking place in it. carbon (OC) is a measure organic matter. For practical purposes, OC divided into dissolved (DOC) particulate (POC). Both DOC POC play major role cycle, especially shelf seas like Baltic, where their concentrations substantial. In three-year study (2009–2011) samples for measurements were collected from stations located Gdańsk Deep, Gotland Deep Bornholm Deep. The accuracy precision analysis satisfactory; recovery was better than 95%, relative standard deviation 4% (n = 5). Concentrations chlorophyll a, phaeopigment salinity, pH temperature also measured same samples. These parameters selected proxies contributing to abundance. aim address questions regarding vertical, horizontal seasonal dynamics both Baltic Sea factors influencing concentrations. general, highest recorded surface water layer (DOC ~ 4.7 mg dm− 3, 0.6 3) consequence intensive phytoplankton activity, halocline 5.1 0.4 3). lowest sub-halocline layer, values did not exceed 3.5 3 0.1 Seasonally, during growing season: 5.0 3; 4.1 ∼ 0.9 0.2 3. ANOVA Kruskal-Wallis test results indicate statistically significant differences among three sites average concentrations, particular layers seasons. It shows that differ sub-basins Sea. attributed varying distances river mouths or different starting times and/or durations spring algal blooms. Statistically dependences found between Chl (phytoplankton biomass), photosynthetic rate), pheo (zooplankton sloppy feeding), salinity (river run-off North inflows) (season). This taken proof these influence areas.