In abyssal deep-sea environments, the most ancient animals on earth - sponges (class Porifera) - are highly abundant. The ecological functions of sponge dominated areas, so called sponge grounds, remain unknown and unquantified. Pinpointing these major knowledge gaps, the research project “Deep-sea Sponge Grounds Ecosystems of the North Atlantic: an integrated approach towards their preservation and sustainable exploitation” was granted in 2016. Wageningen University and Research has the co-lead in the work package “Threats and impacts” and is focusing on how key-species within sponge grounds cope with anthropogenic induced environmental changes and disturbances.
Sponge grounds are benthic ecosystems dominated and densely populated by sponges and are widespread throughout deep-sea habitats in the North Atlantic Ocean. These sponges play a crucial role in the function of benthic deep-sea habitats by providing habitat for several invertebrates and fish species and by nutrient cycling. As of now, little research effort has been addressed to sponge grounds in deep-sea environments. While we hardly understand these ecosystems and their importance for benthic-pelagic-coupling processes, they are already facing anthropogenic induced environmental changes and disturbances.
The PhD project “Effects of multiple environmental drivers on sponges in
the deep-sea” aims at assessing the biological performances (growth-,
respiration- and pumping-rates) of the two deep-water key-species Geodia barretti Bowerbank, 1858 and Vazella pourtalesi (Schmidt, 1870) under
different environmental conditions. By using a multifactorial approach we will show how North Atlantic deep-water sponges may respond to future changes in their environment. First, individuals of the two target species will be long-term exposed to different seawater CO2-concentration and
temperature regimes including those reflecting predicted conditions for the
year 2100. Second, the sponges will be exposed to suspended sediments to evaluate how long-term acclimatized individuals cope with this additional stressor, which simulates resuspension of sediments by fishing or exploitation activities. As deep-water sponges often thrive within the vicinity of oil seepages, we will also test the hypothesis that sponges metabolize certain fossil hydrocarbon compounds. This study will be the first to examine how these potential metabolic pathways might influence the potential of sponges to cope with changing environmental conditions. Multifactorial ex situ experiments on the effects of the different stressors on physiological performances of two sponge species allows an identification and quantification of the individual and cumulative impacts of climatic drivers and local interactions on the functioning of deep-water sponge grounds in the North Atlantic Ocean.
Details about the organisation and scope of the SponGES project can be
found on www.deepseasponges.org