Project description:Analysis of microbial community composition in arctic tundra and boreal forest soils using serial analysis of ribosomal sequence tags (SARST). Keywords: other
Project description:Background biology: Global warming has accelerated in recent decades, with the Arctic warming 2–3 times faster than the global average. As a result boreal species are expanding into the Arctic, at a pace reflecting environmental warming. Nevertheless, the poleward expansion of boreal marine species is restricted by their ability to tolerate low water temperatures, and in the case of intertidal species, sub-zero air temperatures during winter. In Greenland, however, the number of days with extreme sub-zero air temperatures has decreased by more than 50% since the 1950’s, suggesting that the low air temperature constraint is weakening. Although boreal intertidal species could potentially benefit from this warmer climate to establish populations in the Arctic, recent work has shown that local intertidal summer air temperatures in Greenland can exceed 36°C. This temperature is above the thermoregulatory capacity of many boreal intertidal species, including the highly abundant blue mussel Mytilus edulis. Therefore will further colonisation of M. edulis in Greenland be inhibited by the increasingly warm summer temperatures. Aim of experiment: Intertidal animals (Greenland blue mussel M. edulis) were sampled in situ on the first warm days of the year from the inner (warmer) and outer (cooler) regions of the Godthåbsfjorden around Nuuk (64°N) to examine the fjord temperature gradient effect. In addition, subtidal M. edulis were also collected and subjected to two acute temperature shocks of 22 and 32°C, which represented common and extreme summer air temperatures for intertidal habitats near Nuuk.
Project description:The objective of this study was to identify the different functional genes involved in key biogeochemical cycles in the sub- Arctic regions. Understanding the microbial diversity in the Arctic region is an important step to determine the effects of climate change on these areas.
Project description:Microbial decomposition of soil organic carbon (SOC) in Arctic permafrost is one of the most important, but poorly understood, factors in determining the greenhouse gas feedback of tundra ecosystems to climate. Here, we examine changes in the structure of microbial communities in an anoxic incubation experiment at either –2 or 8 °C for up to 122 days using both an organic and a mineral soil collected from the Barrow Environmental Observatory in northern Alaska, USA. Soils were characterized for SOC and geochemistry, and GeoChips 5.0 were used to determine microbial community structure and functional genes associated with C availability and Fe(III) reduction.
Project description:Arabidopsis thaliana is not particularly stress tolerant and may lack protective mechanisms required to survive extreme environmental conditions. Thellungiella salsuginea has therefore attracted increasing interest as an alternative plant model species that possesses high tolerance of various abiotic stresses. While the T. salsuginea genome has recently been sequenced, its annotation is still far from complete and, due to the low number of ESTs available, evidence for actual transcriptional activity is lacking for most genes. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions. The ESTs of Thellungiella was sequenced by 454 pyrosequencing method. More than 1 million sequence reads were assembled into 42,810 unigenes, approximately 50% of which could be functionally annotated. From this sequence information, we constructed a 44k Agilent oligonucleotide microarray. A comparison of same-species and cross-species hybridization results showed the superior performance of the newly designed array for Thellungiella samples. In addition, the array was validated in a cold acclimation experiment that used the appropriately adapted MapMan software for analysis and visualization.
