Sediment trap diatom counts from Tvärminne Archipelago, Gulf of Finland, Baltic Sea

Diatom counts were analysed from sediment trap samples collected from Tvärminne Storfjärden, Gulf of Finland, Baltic Sea, between October 2012 and October 2013 as a part of Winter Ecology project. Automated cylindrical Hydrobios Multi sediment trap (aperture 0.0015 m²) was deployed at 15-meter water depth, approximately 15-m above sea floor. The rotation for the sediment trap was set to 7-day intervals, some samples were combined to represent 2-to-8-week intervals. Diatoms were counted and identified using a Zeiss Axio Imager.A2 light microscope, Plan-Apochromat 100×/1.4 oil immersion objective, phase contrast optics and a total magnification of ×1000.