Jorma Kuparinen,^* Liisa Tuominen<sup>**


*</sup>Jorma Kuparinen is the Head of the Department of Biological Oceanography at the Finnish Institute of Marine Research. His research experience extends over the last 22 years. His main interest has been on microbial ecology with specific focus on the carbon cycle. His field studies have often been supplemented with experimental studies in microcosm including manipulations with environmental factors such as nitrogen, phosphorus and carbon. Rate measurements, based on isotope incorporation techniques (H, C, P and N) as well as biomass estimates by various microscopic techniques have been applied and developed in the studies. His address: Finnish Institute of Marine Research, P.O. Box 33, FIN-00931 Helsinki, Finland. jorma.kuparinen@fimr.fi
^**Liisa Tuominen is a research scientist in the Department of Chemical Oceanography at the Finnish Institute of Marine Research. Her research experience extends over the last 12 years. Her main interest has been on the nutrient-flux studies in the sediment-water interface in both lake and Baltic sediments. Her field studies have been supplemented with experimental microcosm studies with manipulation by environmental factors such as nitrogen, phosphorus, carbon and silicate. Rate measurements, based on isotope incorporation techniques (H, C, P and N) have been applied and developed in her studies. Her address: Finnish Institute of Marine Research, P.O. Box 33, FIN-00931 Helsinki, Finland. liisa.tuominen@fimr.fi