ABSTRACT BOOK Keynote – Presentation

2.7.–7.7. 2017 / Olomouc, CZ ABSTRACT BOOK Keynote – Presentation IMPLICATIONS OF GLOBAL CHANGE FOR AQUATIC COMMUNITIES: DO MICRO-EVOLUTIONARY SHIFTS IN POPULATION FUNCTIONAL TRAITS MAKE A DIFFERENCE? Steven Declerk ([email protected])1 1 Netherlands Institute of Ecology, Wageningen, NL By most ecologists, species are considered as entities with fixed traits because rates of evolutionary adaptations are believed to be much slower than the rate of ecological dynamics. However, it is only in the latest years that an increasing number of ecologists come to re- alize that microevolutionary adaptation can take place at ecological time scales. Although microevolutionary trait shifts may seem small and insignificant in magnitude compared to the large trait changes that are documented for macro-evolutionary time scales, they may still be of considerable importance from an ecological perspective, as they may strongly determine the performance of contemporary populations and their interactions with the biotic and abiotic environment. This is especially relevant in the context of current global change, with anthropogenic impacts that cause the biotic and abiotic environment of organisms to change at unprecedented rates. In this talk, I will introduce the concept of eco-evolutionary dynamics, illustrate its relevance for aquatic systems with a variety of examples and try to address the question whether such dynamics may effectively contrib- ute to a better understanding of the response of aquatic biota to anthropogenic pressures. 2 ABSTRACT BOOK / 2.7.–7.7. 2017 / OLOMOUC, CZ 3 Keynote – Presentation Keynote – Presentation SERENDIPIDY IN SCIENCE – 35 YEARS STUDYING A TROPICAL MICROBIAL NITRIFICATION IN URBAN STREAMS: FROM SINGLE LAKE CELL ACTIVITY TO ECOSYSTEM PROCESSES David Harper ([email protected])1 Stephanie N. Merbt ([email protected])1 2 Nic Pacini 1 EAWAG, Switzerland 1 University of Leicester, UK 2 University of Calabria Ammonia oxidization is the first and rate-limiting step of nitrification, which connects ecosystems’ nitrogen (N) inputs (fixation, mineralization) with losses (denitrification, anamox). Lake Naivasha, Kenya, was once a rather unusual lake, but is becoming ordinary as it fills Ammonia oxidization is carried out by both ammonia oxidizing archaea (AOA) and bac- with alien species that are now commonplace and it becomes surrounded by developments teria (AOB). Although sharing a common function, AOA and AOB are phylogenetically dis- and settlements. This presentation looks at 50 years of change in the lake through the 35 tinct, suggesting different ecological adaptations and phenotypic characteristics. In high N years we have been studying it and whether the knowledge of its limnology acquired, is any loaded ecosystems, such as urban streams receiving effluents from wastewater treatment use in its management. A small (100-140km2) freshwater lake in a chain of mostly saline-al- plants (WWTP), ammonia oxidization is highly relevant, and microbial biofilms growing kaline lakes running along the predominantly arid Eastern Rift Valley floor between Ethio- on submerged substrata carry out a fundamental role. Despite the pivotal effect of high pia and Tanzania, Naivasha has always been essential to human existence and, since colo- N concentrations in triggering eutrophication of downstream waters, there are only few nization in the lake 19th Century, drawn settlement. People had little impact on its ecology mechanistic insights on how ammonia oxidation is controlled in human altered streams. before the middle of the 20th Century, but an increasing list of deliberate introductions and In my PhD thesis, I aimed to unveil regulating factors and driving mechanisms of ammonia accidental arrivals of alien species, that is still continuing, mean that the lake ecosystem is oxidation from single cell to community and ecosystem scales through the combination of wholly novel beneath the water, yet can appear little changed above. In parallel to the alien a large variety of molecular and biogeochemical tools in both field and laboratory experi- invasion, agricultural and horticultural developments, bringing several hundred thousand ments. In my presentation, I will show how the effluent of WWTPs shapes the distribution, people in new settlements, have markedly changed the lake hinterland and threatened its community composition and activity of AOA and AOB and how this shift is reflected in dif- water quality. Intense subsistence cultivation throughout the catchment with increasing ferential nitrification rates at ecosystem scale. Moreover, I will unveil differential photo- population reduce the quality and quantity of incoming river waters. Against these threats sensitivity of ammonia oxidizing organisms as an important driver for niche separation; to its ecology, the lake responds with the most fickle hydrology imaginable, as a conse- and how habitat heterogeneity within stream reaches influences the spatial distribution of quence of the Inter Tropical Convergence Zone. Seemingly about to become a dustbowl ammonia oxidizers at whole-reach scale. Finally, I will evaluate the relative contribution of in 2009 through over-abstraction on top of a natural drought, that brought international different microbial communities (epilithic and epipsammic biofilms) to whole-reach nitri- experts to help write yet more management plans, the lake responded in heavy rains by fication. rising by 2012 to a level last seen in 1969, with native species and high water quality re- turning. With such un-predictability and a near-impossibility of modeling, how useful is its science? Naivasha has been a great training ground for students and foreign scientists as a first ‘taste’ of Africa, but none of the science has generated any effective monitoring at all to guide sustainable management. Will this change? I shall give you a mentally easy presentation, to help you wake up, on the morning after the conference dinner. 4 ABSTRACT BOOK / 2.7.–7.7. 2017 / OLOMOUC, CZ 5 Keynote – Presentation RS02 – Presentation NEW PERSPECTIVES IN THE STUDY OF LAKE FOOD WEBS A STUDY OF THE POTENTIAL IMPACTS OF CLIMATE CHANGE ON OYSTER PRODUCTION IN WHIN ESTUARY IN GHANA Jake Vander Zanden ([email protected])1 1 1 Center for Limnology, Madison, WI, United States of America Sandra, Akugpoka Atindana ([email protected]) Sandra Brucet2 In this current era of unprecedented global environmental change, studying lakes from 1 University for Development Studies, Ghana a system-wide perspective provides a holistic basis for understanding and conserving lake 2 Olajire, Fagbola ecosystems. In this talk, I’ll highlight several insights into our understanding of lakes that Ghana depends heavily on her coastal resources for food, income and employment with derive from adopting a food web perspective. First, benthic primary production can be an the Whin Estuary being no exception. It is feared that this ecosystem could be lost in the important contributor to whole-lake primary production, and seems to make a dispropor- event of Climate Change (CC) because of its close tie to the sea. This could be magnified tionately large contribution to higher trophic levels. Second, lakes are linked to the sur- by land use activities due to potential impact on food security, livelihood and water. Using rounding landscape through aquatic insect emergence events. Studies from Lake Myvatn, case scenarios, historic mollusc catch and current catch data of West African Oyster (Cras- Iceland have provided a basis for better understanding the role of lake-to-land food web sostrea tulipa) and environmental factors were used as surrogates of the ecological sta- linkages. Finally, compound-specific stable isotope studies are providing new insights into tus and sustainability of oyster fishery. Triangulation approach involving the use of focus long term food web change and historical niche partitioning in fish communities. Food group discussions, key informant interview, field measurements and observations were web studies as discussed here are part of a larger movement to apply more holistic and employed to solicit data on catch, land use activities and perception of oyster harvesters system-wide approaches to the study of lakes. on the fishery. A general linear model was performed to determine the influence of environmental variables on oyster abundance and spatial distribution. Ranking of identified land use stressors were done using the ( Battisti et al., 2009) Salafsky et al. (2003) ranking method. The results of the study showed that mollusc catch decline with increase temper- atures and increase in volume of rainfall. Among the non climatic stressors in the area, the presence of sewage outlets were the major threat (8), followed by uncontrolled mangrove cutting (7), sand winning (6) and the least of the threats were refuse damps(4) and farming activities (3). There was no significant differences in the magnitude of threats of refuse dumps and farming activities. Keywords: Abundance, Catch, Ecological, Oyster, Threats 6 ABSTRACT BOOK / 2.7.–7.7. 2017 / OLOMOUC, CZ 7 RS02 – Presentation RS02 – Poster IMPACTS OF CLIMATE CHANGE ON FOOD WEBS: ROLE OF STRUCTURAL AND FUNCTIONAL RESPONSES OF INVERTEBRATE INDIVIDUAL PHENOTYPIC PLASTICITY AND NON-TROPHIC COMMUNITIES TO CLIMATE CHANGE AND THEIR INTERACTIONS INTERACTIONS WITH FLOW REGULATION IN ALPINE RIVERS David Boukal ([email protected])1 Daniel Bruno ([email protected])1 Arnaud Sentis, Charlène Gémard,

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