Vortragsreihe Ökologie und Umweltforschung SS 2017

Microbial cycling of organic matter and trace gases in a changing ocean

Marine microbes play a crucial role in the production and consumption of climate-active gases. In our studies, we investigate the environmental control on two important microbial pathways leading to the production of climate-active gases in the ocean, (i) the enzymatic hydrolysis and bacterial turnover of organic matter that results in the release of CO₂ and (ii) the formation and cycling of halogenated trace gases which play a significant role in present day ozone depletion.

Heterotrophic bacteria are the main producers of CO₂ in the ocean, thereby counteracting the biological drawdown of CO₂ by primary production. Microbial cycling is currently hypothesized as the main source for oceanic bromocarbons, but with little knowledge of the underlying processes and magnitude of the biogenic sources and sinks. Recently, it has been suggested that reactive halogen species in seawater halogenate dissolved organic matter releasing halogenated trace gases such as bromoform.

Many enzymatic processes involved in the bacterial cycling of organic compounds were shown to be temperature and pH sensitive in previous studies. Due to the continuous rise in atmospheric CO₂ concentration, the ocean is experiencing considerable changes in temperature, carbonate chemistry, and pH at a rate unprecedented during the last 300 million years but the consequences for microbial physiology, organic matter cycling and marine biogeochemistry are still unresolved.

We studied microbial production and removal processes in the surface ocean during research cruises to low and high latitudes as well as during CO₂-manipulation studies simulating future ocean conditions. We conclude that the ongoing ocean acidification has the potential to stimulate the bacterial community and facilitate the microbial recycling of freshly produced organic matter, thus strengthening the role of the microbial production of climate-active gases in the surface ocean.

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Invited by Birgit Thies, BayCEER Office

Im interaktiven Vortrag "Traumberuf Naturwissenschaftler*in" erzählt Sonja Endres am gleichen Abend um 19 Uhr im Glashaus vom Alltag an Bord und beantwortet Fragen zum Karriereweg als Naturwissenschaftler*in (Veranstalter: Educare / Fachschaft BCG).

• Announcement as PDF
• Plakat "Traumberuf Naturwissenschaftler*in"