Jukka Horppila and is comprised of postdoctoral researchers, Ph.D-students and M. Sc. students. The group also co-operates with numerous other research groups, research institutes and companies.
Presently I work as a professor in limnology in the University of Helsinki. I started my research career in the large Lake Vesijärvi restoration project. In my Ph. D. thesis (1994) I explored the effects of fish communities on the water quality of lakes and the possibilities to improve the water quality through food web management. The studies in Lake Vesijärvi produced many new research ideas and hypotheses and led to the foundation of the Lake Ecosystem Dynamics research group that I lead nowadays. My research interests cover all aspects of lake ecosystem dynamics. Consequently, the research of the group has branched to various topics and study sites. During the recent years, the study topics have included, for instance, the role of invertebrate predators in lake food webs and their effects on lake restoration success, the impact of increasing turbulence on predator-prey interactions, the effects of littoral macrophytes on the internal nutrient loading of lakes, the role of sediment resuspension in nutrient cycling, the importance of anoxia in water quality regulation, and the effects of artificial aeration.
I have dissertated from the Lake Ecosystem Dynamics group led by Professor Jukka Horppila in 2003 on the structural and stabilizing role of macrophytes and continued my research career since as a researcher and University lecturer in Limnology. My research interests are broad. I have continued to study the important role of macrophytes and the littoral zone in regulating the dynamics of aquatic ecosystems. Under the structuring function of macrophytes, I have especially focused on the role of floating-leaved vegetation in regulating the light climate and predator-prey interactions in lakes of various water quality and colour.
I am also comprehensively interested in the predator-prey interactions in aquatic ecosystems and intra- and interspecific competition of fish in lakes of varying water quality and colour. Few current research interests are the food web structure of humic lakes and the interaction between the common Eurasian species perch (Perca fluviatilis) and roach (Rutilus rutilus) in eutrophic and humic temperate lakes.
I work as a Post-doc Researcher at the Lake Ecosystem Dynamics research unit in the HUMI-project. I have a strong disciplinary background in freshwater ecology (i.e. limnology) and my research interests include the impact of lake brownification pressure on the lake ecosystems and adaptations of freshwater fish to environmental conditions.
The current project, HUMI (The Humus Load Indicators) is a ten-year research project and funded by the Serlachius Foundation. Project aims to study novel methods for monitoring the effects of loading of disolved humic substances originating e.g. from forestry and peat mining. Also, the aim is to find new tools in the ecological status assessment of lakes.
I am currently working as a Doctoral Researcher in the group, and will defend my thesis in the near future. In my doctoral research project, I studied the potential and functioning of the novel hypolimnetic withdrawal and treatment system at Lake Kymijärvi, Lahti (southern Finland). Hypolimnetic withdrawal and treatment is a closed-circuit application of the conventional lake management method, hypolimnetic withdrawal, and it aims to remove phosphorus and other nutrients by pumping nutrient-rich water through a treatment unit followed by a wetland, and back into the lake. My main goals were to assess the potential and optimization of the method in terms of lake restoration, and to identify biogeochemical processes in the treatment unit.
While finishing my PhD, I am working on a new project in which I investigate the dynamics of hypolimnetic phosphorus during lake turnover in Lake Vesijärvi, Lahti. The aim is to study the potential mechanisms through which internal loading from shallow areas may in the long run be affected by phosphorus upwelling and redistribution from deep stratifying areas. Understanding this link can be helpful when planning lake restoration measures.