Particulate organic carbon, amino acids, combined carbohydrates (>20 µm) and microphytoplankton in surface and underlying water during ELISABETH MANN BORGESE cruise EMB295 (CenBASE) Jul-Aug 2022

Particulate samples were collected in the Eastern Gotland Basin (Central Baltic Sea) during the CenBASE research cruise EMB295, carried out between June 30th and July 19th 2022. Samples from the sea surface were collected twice a day using a Neuston catamaran equipped with a 20 µm mesh net, sampling the upper 20 cm of the water column. Corresponding reference samples from the underlying water (ULW) were collected at approximately 1 m depth using an ULW net. The biochemical composition of the particulate fraction was assessed through measurements of particulate organic carbon >20µm (POC>20µm), particulate amino acids >20µm (PAA>20µm), and particulate combined carbohydrates >20µm (PCCHO>20µm). POC was measured using an Euro EA elemental analyser. To determine the composition of the microphytoplankton community (>20 µm), samples were preserved with Lugol's solution and analyzed according to the Utermöhl method. Sampling stations were categorized based on the relative abundance of microphytoplankton (>20 µm) and nano- and picophytoplankton (≤20 µm).