MICRODIVE · Biodiversity and ecosystem services in the microbial realm

Biodiversity and ecosystem services in the microbial realm

Biodiversity loss and nutrient loading are considered as two major factors affecting the boundaries of a proposed safe operating space for humanity based on ecosystem services. Biodiversity loss in the visible realm is well documented and mechanistic cause and effect relationships between biodiversity and ecosystem functions in terrestrial ecosystems are reported. Hence, in aquatic ecosystems primary producers are often unicellular (phytoplankton) and not visible by eye. There is much less knowledge about their biodiversity, and how this diversity affects the functional traits within a community. Additionally, it is still not sufficiently known how microbial diversity interacts with environmental parameters such as resource supply. The aim of this project was to develop a mechanistic understanding of the complex interactions between phytoplankton biodiversity, functional traits and resource supply in pelagic systems. Within the first two years of the project experiments with freshwater communities were proposed. Several laboratory and large scale field experiments with freshwater communities were performed and show that a loss of biodiversity resulted in lower community resource use efficiency and resilience to nutrient pulses. Both, a loss of stress sensitive species and a loss of rare species had measurable effects on the growth and nutrient use efficiency of phytoplankton communities. Within the second two years of the project experiments with marine communities (to complement experiments with freshwater -communities) were proposed. Several laboratory and large scale field experiments with marine phytoplankton communities were performed and show that a loss of biodiversity resulted in lower community resource use efficiency. Biodiversity of phytoplankton affected diversity from small scale microcosms to large scale observations of oceanic time series (Mediterranean, Atlantic and Pacific Waters) at very similar effect sizes. It seems that the effect size was mainly depending on average species richness of the marine systems. Our results point towards a uniform relationship between phytoplankton diversity, resource use efficiency and productivity, which is an important ecosystem service, in marine phytoplankton communities. New concepts for biodiversity conservation must therefore also include the microbes that fundamentally drive ecosystem services. Such concepts must be based on a detailed understanding of the role of microbial diversity in ecosystem services. In addition to meta-analyses describing diversity-productivity relationships, process-oriented knowledge about the cardinal mechanisms underlying these relationships is urgently needed. Project results were important to successfully achieve additional national and international grants. The fellow has an independent permanent position and is supported by scientific and technical positions and administrative and logistic supply from the Host institution. A field research station allowing performing the proposed freshwater experiments was equipped by funds of the Host institute (http://www.aquatic-ecology.bio.lmu.de/). Together with the permanent position of the researcher this support allows to plan and perform long term field observation and field experimentation which are important research tools for the further career development of the researcher. The establishment of this experimental infrastructure allowed the researcher to successfully participate on the EU H2020-INFRAIA-project No 731065: “AQUACOSM - Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean”, which is just in the process of negotiations.

Data: CORDIS, © European Union