Weathering in the deep sea??

Ingeborg Økland explained that she will be examining the contents of the recovered incubators under the scanning electron microscope looking for changes in the pyrite material and will identify any weathering products.

How is weathering detected?

She expects to see evidence of microbes on the mineral surfaces. The microbial aspect will be explored by CGB researcher, Håkon Dahle. Dahle is part of a group at CGB that undertake meta-omic analyses of microbial communities. These approaches make it possible to determine what proteins are being produced by a community, from this they can deduce what kind of processes are on-going in that community, and this leads, in turn, to indications of the kind of organisms are, in fact, present. In these seafloor samples, it is the organisms that are undertaking oxidation of reduced sulphur and iron  to generate energy that are of particular interest. In addition to causing the weathering, these organisms also serve as primary producers for the local microbial community by building biomass from inorganic carbon compounds.

The incubators had been lying, partially submerged, in the sulphide mounds by the vents. In addition, push cores of the sediment from both inside and outside the mounds were collected. Økland explains that the goal was to study the “fall-out” patterns and spreading of the material being deposited from the vent plumes. In particular the researchers wished to determine if there were differences in weathering products, or in the microbial community structures?

This summer they were also able to collect material from one of the scar sites made at Jan Mayen. Økland described how CGB researchers had been able to dislodge a small chimney at Jan Mayen summer 2014, making a small scar on the sea-floor. They collected a piece of this chimney and some freshly exposed scar surface then. This summer they were able to collect a second set of samples, and thus will be able to compare the samples from the two successive summers and note any weathering changes.

Contributing to on-going socio-economic discussions

Økland’s work is of great importance in view of the current, on-going discussions about renewed resource extraction initiatives in Norway; specifically about the possibility of depositing mine tailings in the fjords. Her work is part of the EU MIDAS project (Managing Impacts of Deep-seA reSource exploitation).

Recent news articles (in Norwegian) about the renewed interest in storing mine-tailings in Norwegian fjords:

https://www.uib.no/aktuelt/82347/kartlegger-arktis-undersj%c3%b8isk-gruvedrift

https://www.uib.no/geobio/58724/trygg-deponering-i-norske-fjorder

http://www.geoforskning.no/reportasjene/66-trygg-deponering-i-norske-fjorder

http://www.bt.no/meninger/kronikk/Nar-fjordene-graner-1775594.html

http://www.bt.no/nyheter/utenriks/Venstre-krever-gruve-svar-3434647.html