Seston are the organisms (bioseston) and non-living matter (abioseston or tripton) swimming or floating in a water body. Bioseston can be often regarded as plankton, although it includes nekton as well. Abioseston comprises detritus as well. Seston are the organisms (bioseston) and non-living matter (abioseston or tripton) swimming or floating in a water body. Bioseston can be often regarded as plankton, although it includes nekton as well. Abioseston comprises detritus as well.