Seeps and Vents

In the deep-sea, cold seeps and hot vents are unique hab­it­ats for an­im­als and mi­crobes. They emit en­ergy-rich flu­ids from the sea­floor thus nour­ish­ing oasis of life in the gen­er­ally food-lim­ited deep-sea.  Di­verse chemo­syn­thetic mi­crobes have evolved us­ing oxy­gen from the sea wa­ter to ox­id­ize hy­dro­gen sulf­ide, meth­ane and other re­duced com­pounds present in seep and vent flu­ids. An­im­als such as mus­sels, clams, and snails  feed on the mi­crobes and heav­ily col­on­ize these areas. In gen­eral, seeps can be dis­tin­guished from vents by their slower seep­age of cold and meth­ane-rich flu­ids from sed­i­ments versus a vig­or­ous vent­ing of hot sulf­ide and metal-rich flu­ids from rocky set­tings.

Cold seeps are wide­spread along con­tin­ental mar­gins. They are char­ac­ter­ized by the emis­sion of nat­ural gas, a mix­ture of hy­dro­car­bons and re­duced flu­ids from sub­sur­face reser­voirs to the sea­floor. In an­oxic lay­ers, the mi­cro­bi­ally-me­di­ated an­aer­obic ox­id­a­tion of meth­ane (AOM) and of other non-meth­ane, short-chain al­kanes is a key biogeo­chem­ical pro­cess form­ing huge mi­cro­bial bio­masses, thus, pre­vent­ing the re­lease of cli­mate act­ive gases into the at­mo­sphere. In this pro­ject we col­lab­or­ate with the HFG-MPG Research Group for Deep-Sea Ecology and Technology (G. Wegener/A. Boetius) and with the MPG Research Group Microbial Metabolism (T. Wagner).
Hy­dro­thermal vents can be found along mid-ocean ridges, in bac-arc basins, at sub­merged is­land arc vol­ca­noes, and at in­tra­plate hot­spots in areas where a heat source such as a magma cham­ber is loc­ated close to the sea­floor. Here, cold oxy­gen­ated sea­wa­ter en­trained in the rock gets heated and chem­ic­ally mod­i­fied be­fore it is again emit­ted into the wa­ter column. These flu­ids are, de­pend­ing on the geo­lo­gical set­ting, en­riched in re­duced com­pounds such as hy­dro­gen sulph­ide, hy­dro­gen, meth­ane and iron. They build the fun­da­ment for chemoauto­trophic life lead­ing to “oases” in the oth­er­wise food lim­ited deep-sea. Our re­search on hy­dro­thermal vents is con­duc­ted within the frame­work of the Cluster of Ex­cel­lence “The Ocean Floor – Earth’s Un­charted In­ter­face” lead by MARUM (Uni­versity of Bre­men)