Benthic cold seep communities play a key role in global elemental and greenhouse gas cycles (carbon, sulfur, methane) because the chemoautotrophic process sustaining them uses these chemicals for energy. Cold seeps in Arctic shelf/upper slope regions are key sites for climate-changing gas fluxes because extensive gas hydrate reservoirs in these areas are considered susceptible to dissociation from small changes in water temperature. However, we know very little about the animals in Arctic shelf/upper slope communities and this project will address this by studying and characterizing Arctic shelf cold seep animal communities off Spitsbergen, and their bacterial symbionts and biogeochemistry. We will identify the chemosynthetic animals and their symbiotic bacteria. We will identify the energy source (sulfide vs. methane), as well as where and how it is taken up, and the structures and mechanics for oxygen uptake and transportation in the worms. Towards this objective, we will use specialized techniques (electron microscopy, in situ fluorescence hybridization, amplification of metabolic genes, biometry analyses, hemoglobin purification) together with analysis of geochemical sediment profiles. Since the study animals are poorly studied and likely to include new species, some fine tuning of protocols will be required. However, the French collaborators are experts on the techniques proposed, particularly with respect to chemosynthesis based animals.
Our knowledge of the biology and geochemical effects of siboglinids is very scarce, and since these worms are ubiquitous in the deep sea, we are addressing a gap that is applicable to the largest habitat on earth. Siboglinids are considered model systems for studying animal-microbe symbioses, therefore the project will be relevant within this context as well. Additionally, our results will help fill in gaps in current climate models, since benthic cold seep animal communities represent an important sink for marine methane.