Coupling pathway prediction and fluorescence spectroscopy to assess the impact of auxiliary substrates on micropollutant biodegradation.

Some bacteria can degrade organic micropollutants (OMPs) as primary carbon sources. Due to typically low OMP concentrations, these bacteria may benefit from supplemental assimilation of natural substrates present in the pool of dissolved organic matter (DOM). The biodegradability of such auxiliary substrates and the impacts on OMP removal are tightly linked to biotransformation pathways.

Remediation of marine dead zones by enhancing microbial sulfide oxidation using electrodes.

Marine dead zones caused by hypoxia have expanded over the last decades and pose a serious threat to coastal marine life. We tested sediment microbial fuel cells (SMFCs) for their potential to reduce the release of sulfide from sediments, in order to potentially protect the marine environment from the formation of such dead zones. Steel electrodes as well as charcoal-amended electrodes and corresponding non-connected controls of a size of together 24 m were installed in a marine harbour, and the effects on water quality were monitored for several months.

Removal of dissolved organic matter from the woodchip bioreactor start-up by foam fractionation.

Denitrifying woodchip bioreactors are passive, low-tech systems primarily designed to remove nitrate from shallow ground waters as well as point source discharges. Despite their capacity to achieve constant nitrate removal over several years, natural aquatic environments may be affected by the leaching of dissolved organic matter (DOM) from fresh woodchips during start-up. Simple on-site measures might reduce the woodchip leachate during start-up and thus add to the overall environmental sustainability of woodchip bioreactor installations.

Glacial meltwater determines the balance between autotrophic and heterotrophic processes in a Greenland fjord.

Global warming accelerates melting of glaciers and increases the supply of meltwater and associated inorganic particles, nutrients, and organic matter to adjacent coastal seas, but the ecosystem impact is poorly resolved and quantified. When meltwater is delivered by glacial rivers, the potential impact could be a reduction in light and nutrient availability for primary producers while supplying allochthonous carbon for heterotrophic processes, thereby tipping the net community metabolism toward heterotrophy. To test this hypothesis, we determined physical and biogeochemical parameters along a 110-km fjord transect in NE Greenland fjord, impacted by glacial meltwater from the Greenland Ice Sheet.

Vertical redistribution of principle water masses on the Northeast Greenland Shelf.

The Northeast Greenland shelf (NEGS) is a recipient of Polar Water (PW) from the Arctic Ocean, Greenland Ice Sheet melt, and Atlantic Water (AW). Here, we compile hydrographical measurements to quantify long-term changes in fjords and coastal waters. We find a profound change in the vertical distribution of water masses, with AW shoaling >60 m and PW thinning >50 m since early 2000's.