Variation in benthic long-term data of transitional waters: Is interpretation more than speculation?

• Published in: PloS one Vol. 12; no. 4; p. e0175746
• Main Authors: Zettler, Michael Lothar, Friedland, René, Gogina, Mayya, Darr, Alexander
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.04.2017; Public Library of Science (PLoS)
• Subjects: Abundance; Advection; Animals; Anthropogenic factors; Aquatic habitats; Atlantic Ocean; Atmospheric models; Baltic States; Basins; Bathymetry; Bayesian analysis; Benthic communities; Benthic fauna; Biodiversity; Biogeochemistry; Biology and Life Sciences; Biomass; Brackish water; Change detection; Chemical analysis; Climate; Climate and human activity; Climate change; Climate models; Coastal ecosystems; Coasts; Community composition; Community structure; Cooperation; Data processing; Deep sea; Driving ability; Earth sciences; Ecology and Environmental Sciences; Ecosystem; Environment models; Environmental changes; Environmental impact; Environmental monitoring; Environmental protection; Eutrophication; Fisheries; Fluctuations; Glaciation; Human influences; Humans; Hypoxia; Indicator species; Inhabitants; Legislation; Marine ecosystems; Models, Statistical; North Atlantic Oscillation; Oxygen; Oxygen - analysis; Physical Sciences; Precipitation; Rainfall; Ranking; Saline water; Salinity; Salinity effects; Seawater; Seawater - chemistry; Species richness; Statistical analysis; Statistical analysis of data; Summer; Temperature; Temperature effects; Trends; Variables; Water analysis; Water depth; Water pollution; Water quality; Wind direction
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0175746

Biological long-term data series in marine habitats are often used to identify anthropogenic impacts on the environment or climate induced regime shifts. However, particularly in transitional waters, environmental properties like water mass dynamics, salinity variability and the occurrence of oxygen minima not necessarily caused by either human activities or climate change can attenuate or mask apparent signals. At first glance it very often seems impossible to interpret the strong fluctuations of e.g. abundances or species richness, since abiotic variables like salinity and oxygen content vary simultaneously as well as in apparently erratic ways. The long-term development of major macrozoobenthic parameters (abundance, biomass, species numbers) and derivative macrozoobenthic indices (Shannon diversity, Margalef, Pilou's evenness and Hurlbert) has been successfully interpreted and related to the long-term fluctuations of salinity and oxygen, incorporation of the North Atlantic Oscillation index (NAO index), relying on the statistical analysis of modelled and measured data during 35 years of observation at three stations in the south-western Baltic Sea. Our results suggest that even at a restricted spatial scale the benthic system does not appear to be tightly controlled by any single environmental driver and highlight the complexity of spatially varying temporal response.