Merli Pärnoja will defence the dissertation in hydrobiology "Patterns of macrophyte distribution and productivity in coastal ecosystems: effect of abiotic and biotic forcing".
on the 11th of September at 10.15.
Supervisor: Lead Resarch Fellow Jonne Kotta, PhD (University of Tartu)
Opponent: Thomas Wernberg, PhD (The University of Western Australia, Australia)
The ultimate goal in ecology is to understand biotic patterns, processes and their changes in nature. The vast majority of studies have been performed on limited spatial scales even though the studies covered larger areas than the grain size i.e. the size of sampling units still remained small and vast areas between grains were left unstudied. In the current thesis the machine learning technique combined with statistical modelling, remote sensing and traditional spatial modelling variables succeeded in identifying and testing effects of abiotic environmental predictors on the coverage of benthic macrophyte and invertebrate species from local to seascape scales. In general, exposure to waves and partly water depth and sediment characteristics were the best predictors of the distribution patterns of benthic species. Overall, wind patterns best explained variability in the coverage of shallow water species whereas coastal geomorphology largely contributed to the models of deep water species. Supporting field experiments also demonstrated the strong importance of abiotic forcing to the photosynthesis of macroalgae. Specifically, in coastal environments, where light is supposedly plentiful, macroalgal communities are nevertheless strongly light limited. The experiments also showed that photosynthetic production was more stable at community than species level. Thus, the canopy-forming algae are not just providers of biodiversity but also provide stable photosynthetic production (i.e. food and habitat resource) through the large range of hydrographical conditions.