IMIS - Marine Onderzoeksgroepen

Bacterioplankton growth rate is an indicator of nutrient status in aquatic environments. Growth rate is an estimate of the consumption of organic carbon in the ecosystem and therefore closely related to the in situ biochemical oxygen demand (cf. BOD7). The growth rate thereby indicates the rate of oxygen consumption that may lead to oxygen deficiency in the water column when exceeding the oxygen supply. Data should be sampled and analyzed according to the HELCOM COMBINE Manual - Part C Annex C11 Guidelines concerning bacterioplankton growth determination (https://helcom.fi/media/documents/Manual-for-Marine-Monitoring-in-the-COMBINE-Programme-of-HELCOM_PartC_AnnexC11.pdf). However, deviations from the manual might occur. Information about the program and the methods are available in Swedish at the website of Swedish Agency for Marine and Water Management, https://www.havochvatten.se/hav/vagledning--lagar/vagledningar/ovriga-vagledningar/undersokningstyper-for-miljoovervakning/undersokningstyper/bakteriell-syrekonsumtion.html. It is recommended to take at least 2 samples at different representative depths of the monitored layers of the water column. Surface layer and deepest layer are prioritised. A sampling frequency of 10 samples per year is preferred for confident annual estimates. Samples should be distributed in the seasonal curve to provide a good coverage of different levels.