DFG-Schwerpunktprogramm 1158 "Antarktisforschung"

Climate change induced shift in cyanobacterial mat species
(psychro-tolerant – thermo-tolerant) in the Arctic and Antarctica

Aim of this study:

Exploratory and preliminary assessment of the diversity of cyanobacterial species in cyanobacterial mats of Byers Peninsula (Antarctica) as well as of North Baffin island, Canadian Arctic, cyanobacterial toxin production and effects on co-occurring grazers, as a means to determine the effects of climate change and the associated invasion and/or evolution of more thermotolerant and toxin producing strains of cyanobacteria on the ecosystems present.

Within the scope of the Spanish IPY 2008 / 2009 Limnopolar project (Homepage), we participated in an expedition to the Antarctic Peninsula (Livingstone Island, Byers Peninsula ASPA 26) in February 2009. During this expedition samples from five different cyanobacterial mats of different locations were collected (Figure 1 and 2a). The project, initially limited to the investigation of cyanobacterial mats of the Antarctic Peninsula, was expanded in a geographic context to determine differences in diversity and toxin production between Arctic and Antarctic cyanobacterial mats. Consequently, additional Antarctic sampling sites and cyanobacterial mats from the Canadian arctic were and will be included. Some cyanobacterial mat samples were already collected by Dr. Frithjof Küpper (Scottish Association for Marine Science, Scotland) during an expedition to the Canadian arctic in September 2009. Dr. Küpper will be a collaborating partner in the further progress of our project. Moreover, a close collaboration with Dr. Susie Wood from the Cawthron institute, New Zealand, was established and includes collaborative analyses of cyanobacterial species diversity and toxin production, specifically from cyanobacterial mats from throughout different locations of the Antarctica. Similarly, a a result of the Limnopolar project, a close exchange of data on cyanobacterial mat diversity from previous sampling years was established between Prof. Antonio Camacho (University of Valencia) and Prof. Antonio Quesada (Universidad Autonoma de Madrid).

Fig.1: Top left: Camp on Byers Peninsula, Antarctica. Top right: Prof. Dan Dietrich getting ready for scubadiving in lake Limnopolar (an Antarctic freshwater lake) to measure, characterize and collect submersed mosses. Bottom left: Antarctic vegetation with cyanobacterial mats.

Preliminary Results:

1. Study Sites

Cyanobacterial mat samples were analysed from two different study sites. The first study site is located on Byers Peninsula, Livingston Island, Antarctica. The second site is located on North Baffin Island, Canadian Arctic. Both environments show similar characteristics, in as such as they present with a large ice-free area in the summer moths, are located close to the sea, and have similar vegetation patterns. On both sites cyanobacterial mats represent the main primary producers within the terrestrial habitat. Photographs of those mats can be seen in Figure 2 A and 2 B.

Fig.2: Cyanobacterial mat from Byers peninsula (A) and North Baffin Island (B). Picture (A) shows rectangular cut outs where mat sample had been removed.

2. Characterization of cyanobacterial diversity of Arctic and Antarctic mats

The presence of cyanobacterial species could be proven for all mat samples based on the 16S-rRNA-Gene in a standard PCR approach. Light microscopy revealed the presence of mainly filamentous cyanobacterial forms, but unicellular species could be detected as well. Heterocyst forming species indicate the presence of Nitrogen fixing species. Furthermore, the fragment length analysis of the ITS region between the 16S and 23S rRNA genes, allowing to determine species diversity, revealed a high clustering of the arctic mat samples, while cyanobacteria from the Antarctic habitat were more widely distributed. Sample 4-2 which was only in a short distance (10-15 meters) from sample 4 was found to show a completely different species composition than all other samples (Figure 3).

Fig.3: Relationship of the mat community from Arctic and Antarctic cyanobacterial mats based on the ITS sequences and analysed by ARISA (Automated Ribosomal Integrated Spacer Analysis). Sample points Cy 1 – 4-2 resembling Antarctic and samples Cy A – D Arctic cyanobacterial mats. Cy B, C could yet not successfully been amplified.

3. Cultivation of cyanobacterial species from Arctic and Antarctic mat material

Preliminary experiments have been carried out to find out optimal culturing conditions for the cyanobacterial mats. Cultivation was executed in BG11 medium at two different temperatures (4°C and 21°C) and constant light intensities. Cyanobacterial growth occurred selectively with different species compositions in accordance to temperature. In future experiments whole mat samples will be cultivated as an intact system at different temperatures to simulate the effect of climate change on the whole mat system.

4. Determination of the ability of toxin production

Different primer sets have been tested to evaluate the genetic basis for the production of cyanobacterial toxins (i.e. microcystin, nodularin) on DNA level via PCR. Primers were tested using a positive control that is described to produce microcystin (Microcystis aeruginosa CCAP 1450/10, 1450/16). To date in three of the mat samples genes for microcystin production could be detected including a polyketide synthetase, mcyB as well as mcyE, indicating the potential of toxin production in the mats.

Further progress of the project

The project is going to be extended to a minimum of three years in order to incorporate a PhD-thesis (which commenced October 1, 2009). Within this time further excursions to the Arctic and / of Antarctica are planned either by the scientist directly working on this project or by collaborating partners (see below). During these expeditions collection of more cyanobacterial mat samples from geographically and geomorpphologically different locations of the Polar Regions. Moreover, as temperature effects are expected to become manifest in cyanobacterial mats only very slowly is planned to return to the same mats already sampled multiple times over the coming years.

Cooperating Partners:

Dr. Frithjof Küpper, CCAP (Culture Collection of Algae and Protozoa), Scottish Association for Marine Science, Scotland

Dr. Susie Wood, The Cawthron Institute, Nelson, New Zealand

Prof. Dr. Antonio Camacho, University of Valencia, Spain

Prof. Antonio Quesada, Universidad Autonoma de Madrid, Spain

Scientists

Daniel Dietrich
Human- and Environmental Toxicology
University of Konstanz
Germany

Daniel.Dietrich@uni-konstanz.de
Phone: 0049 (0)7531 88 3518

Julia Kleinteich
Human and Environmental Toxicology
University of Konstanz
Germany

Julia.Kleinteich@unoi-konstanz.de
Phone: 0049 (0)7531 88 4105

Research areas

Byers Peninsula (Antarctica), North Baffin island (Canadian Arctic)

Publications

Jungblut AD, Höger S, Mountfort D, Hitzfeld BC, Dietrich DR, Neilan B, Neilan A, 2006. Characterization of microcystin production in an antarctic cyanobacterial mat community. Toxicon, 47(3): 271-278.

Jungblut AD, Hawes I, Mountfort D, Hitzfeld B, Dietrich DR, Burns BP, Neilan B, Neilan A, 2005. Diversity within cyanobacterial mat communities in cariable salinity meltwater ponds of McMurdo Ice Shelf, Antarctica. Environ Microbiol 7(4):519-529.

Hitzfeld BC, Lampert CS, Spaeth N, Mountfort D, Kaspar H, Dietrich DR, 2000). Toxin production in cyanobacterial mats from ponds on the McMurdo iceshelf, Antarctica. Toxicon, 38:1731-1748.

Hitzfeld BC, Fischer WJ, Lampert C, Kaspar H, Dietrich DR, 1998. Protein Phosphatase Inhibiting and Cytotoxic Activity in Extracts of Cyanobacterial Mats Collected from Antarctic Meltwater Ponds, Toxicological Sciences, 42(1-S):288.

Homepage

Homepage Umwelttoxikologie - Uni Konstanz

Research funding organisation