Microbial Ecology

"...the relationships between microorganisms and their environments have a crucial role in the health of the planet and all of its inhabitants."

(Nature Microbiological Reviews, Editorial Board, 2008)

Research aims at understanding the microbial diversity and activities in the marine environment. Microorganisms occur nearly everywhere in the marine environment and thus play a crucial role in decomposition of organic matter and cycling of nutrients. Additionally bacteria are linked to higher trophic levels, e.g. serve as food source for a number of organisms, thus their characteristics are also linked to higher trophic levels (i.e. phytoplankton, zooplankton, and mussels).

At present, we concentrate mainly on the North Sea, with its diverse habitats focusing especially on how different bacterial groups and populations are influenced by climate change. Accordingly we have recently expanded also into polar and brackish environments.

Research topics:

  • Microbial ecology of methanotrophic bacteria
  • Foodweb Interactions
  • The changing coast
  • Long term ecological research (LTER)
Ocean acidification

Team

Dr. Ingeborg Bussmann

Dr. Gunnar Gerdts

Dr. Antje Wichels

Birte Beyer (Master Student)

Hilke Döpke (BTA)

Alexa Garin (PhD Student)

Sidika Kirmizi (PhD Student)

Inga Kirstein (PhD Student)

Karl-Walter Klings (BTA)

Claudia Lorenz (PhD Student)

Judith Lucas (PhD Student)

Anna Matousu (PhD Student)

Roman Osudar (PhD Student)

Dr. Sebastian Primke (Post Doc)

Patrick Schaal (Master Student)

Julian Schubert (Master Student)

Maike Timmermann (Master Student)

Research Themes

Microbial ecology of methanotrophic bacteria

The aims and objectives of my group are microbiological and geochemical studies related to aerobic methane consumption in the water columns and sediments. We characterise natural environments (e.g. lakes and coastal waters) with respect to their importance as methane sink and source and analyse the temporal and spatial distribution and dynamics of methane distribution, emission and ebullition. Based on these ground truthing assessments, we experimentally test the potential and the limitations of aerobic methanotrophic bacteria living in these environments.

Using gas chromatorgraphy and different methane isotopes, we measure methanotrophic activities and quantify the methane dynamics. In the lab, we additionally cultivate methane oxidizing bacteria and conduct eco-physiological experiments. In cooperation with the “Molecular Ecology” and “Geomicrobiology” group the different methanotrophic communities and isolates are characterized on a molecular level.

Our research area reaches from freshwater and coastal methane seepage, as well as boreal and polar estuaries (Fig. 2), i.e. Lake Constance and off Svalbard, Elbe-Estuary with North Sea and Lena-Delta with Laptev Sea. From these different geographic settings we want to compare the eco-physiological characteristics of the methane oxidizing bacteria.

 

Association in PACES: Topic 1 WP5 & Topic 2 WP1

Dr. Ingeborg Bussmann

Methane project019 (Photo: Alfred Wegener Institut)

Foodweb interactions

Bacteria are abundant in all marine habitats, from the sea surface to the greatest depths. Although often ignored they are one of the most important players in the marine food web. Bacteria are directly or indirectly linked to all partners within the marine food web via nutrient cycling and trophic cascades. Bacteria are highly flexible and are able to adapt to changing environmental conditions. Recently in our group pro/eukaryotic interactions in the pelagic food webs were investigated with respect to several different organisms e.g. bacteria/microalgae interactions, regarding the microbiome of marine copepods and regarding jellyfish and bacteria, since "jellies" seem to gain importance in the pelagic food web in the last years.

Previous project:

  • Bacteria associated with Jellyfish

The changing coast - A molecular perspectives

Particles of microplastic, Photo: Oberbeckmann

The ecosystem of the German Bight is not only one of the worldwide “hot spots” strongly affected by climate change but - as an important economic region - also subject to numerous direct anthropogenic influences like tourism, fishery operations, shipping traffic, pollution & eutrophication from various sources, and recently, the set up of wind farms at sea. With our focus on microbes these two aspects, climate change and anthropogenic pressure are under investigation in this topic.

In this context, environmental surveillance efforts are unfortunately mostly focused on for-years-established parameters defined by OSPAR or BLMP but in most cases completely ignoring those organisms which really drive the ecosystem: the bacteria. Based on a few pilot-projects, we aim to “bring the bacteria to public perception”, hopefully leading to a revised comprehension of surveillance agencies for future environmental monitoring concepts.

PACES: Topic 2 WP2

 

Previous Projects

  • Molecular and phylogenetic characterization of the benthic bacterial communities of the German Bight
  • Ocean acidification effects on marine bacterial communities
  • Seasonality of pathogenic Vibrio spp. in seawater, plankton, and shellfish of North and Baltic Sea
  • MICROPLAST (BMBF project)

 

Current Projects

  • Lytic and lysogenic Vibriophages: Incidence of lateral gene transfer on the host

·         The role of marine fungi in marine ecosystems

  • Identification and Quantification of potential human pathogenic Vibrios in situ and in contaminated ballast water
  • Microplastic in the aquatic system
  • Microplastic biofilms source for the dispersal of potentially pathogenic bacteria

Microplastic in marine Sediments

Long term ecological research

In the German Bight of the North Sea, about 60 km to the northwest of the River Elbe and River Weser estuaries lies the island of Helgoland (54°11.3’N, 07°54.0’E) which is characterised by a highly diverse marine life that inhabits inter- to sub-tidal habitats. In 1962, the Biologische Anstalt Helgoland (BAH) initiated a series of daily measurements and water samplings at the station “Kabeltonne” at Helgoland Roads, , a fixed mooring in the vicinity of the island. The recorded data include physico-chemical parameters such as temperature, salinity, Secchi-depth, and concentrations of dissolved inorganic nutrients (phosphate, nitrate, nitrite, ammonium, silicate), as well as biological parameters such as qualitative and quantitative data on phytoplankton and microorganisms. By now, the ongoing Helgoland Roads time series continuously covers a period of more than 40 years and thus is among the longest of its kind worldwide. Climate change with increasing seawater temperature and acidification of the sea also may alter niches for microorganisms. Pathogenic microorganisms might profit from these climate changes also in temperate waters. Against this background long term studies on bacterial diversity and succession in combination with hydrographical and oceanographical data will provide important information on the changes in the marine environment.

PACES: Topic 2 WP2

 

Previous projects:

  • Bacterial communities of marine bioaerosols
  • Microbial diversity, metagenomics and ecosystem monitoring at the long term ecological research station Helgoland

 

Current projects:

Spatial and temporal dynamic of the microbial community in the German Bight