How bioinvasions and parasites modulate climate change impact on benthic communities

Funded by the German Federal Ministry of Education and Research
Duration: March 2019 to February 2022

In this collaboration between the Aquatic Ecology of the University Duisburg-Essen, Germany, the Benthic Ecology group of the GEOMAR in Kiel, Germany, and the group Marine Biology of the National Institute of Oceanography in Haifa, Israel, we investigate consequences of climate change on the environmental conditions of marine food webs. We intend to find out, how competition and grazing in macrophyte-based communities in the Baltic Sea and the Levante respond to effects of climate change (warming, acidification), bioinvasions, epiphytism, and parasitism.

Global change impacts species directly (physiologically) and indirectly (e.g. via shifting biotic interactions). Particularly the indirect impacts are rarely assessed and quantified in current marine ecological research – especially in multispecies communities where interdependent interactions create non-linear feedback. We will elucidate the core interactions of competition and grazing in macrophyte-based assemblages.

In detail, we intend to accomplish the following research aims:

• Measure the performance of native and invasive algae and their native and invasive consumers under a wide range of temperature and pH and compare the location and range of their comfort zones.
• Measure the growth rates (as a real-time fitness proxy) of native and invasive macroalgae with and without epiphytes under different ocean acidification and warming (OAW) scenarios.
• Compare the choice and consumption rates of grazers between native and invasive prey macroalgae.
• Compare the rate of consumption on epiphytes on native and invasive macroalgae by native and invasive mesograzers (crustaceans, snails, fish) under a range of OAW scenarios.
• Measure the consumption rates of grazers with different levels of infestation of parasites on macroalgae and epiphytes.
• Measure the rate of parasite infestation and the parasite effect on the host under different OAW scenarios.
• Model the changes in ecosystem functions and services based on the experimental results.

Contact: Prof. Bernd Sures, Dr. Daniel Grabner, Dakeishla Diaz-Morales