The research plan for this project covered a comprehensive description of site variability at different locations in the Arctic with special emphasis on soils and soil microbes. These should be used as a link between the above-ground and below-ground biomass. Interest thus focuses on interactions between vegetation and soil organisms, i.e., bacteria, fungi, cyanobacteria, soil algae and small soil dwelling animals, as well as soil organic matter.

Descriptions and analyses of sites and their below-ground aspects were carried out close to the common plots of Theme B – Biodiversity in the Arctic tundra, which focused on quadrats (20 x 20m) primarily in a mesic and a dry area. In relation to the vegetation analyses, which were performed in co-operation with other projects, soils were described and sampled for the purpose of evaluating their taxonomical properties (mainly according to the Soil Taxonomy, 8th ed.). Different sub-samples were used to analyse the organic and inorganic matter and the soil micro-organisms.

Studies of soils and soil microbes were carried out at all sites visited (table 1). Soil pits were dug down to 1 m depth or until the permafrost levels were reached. As permafrost can be assumed for all places in the region of this cruise, soils can generally be expected to fall into the order of Gelisols. Here, they fell into the suborders of Orthels and only a few into Turbels. The reason for this is that our sampling sites were not affected by active permafrost much, although permafrost patterns could be monitored at other places in the wider landscape, e.g., on Banks Island. Often, soil frost patterns were observed as large stripes along hill slopes, e.g., Somerset Island and Bathurst Island. The permafrost table was generally shallower at mesic sites and deeper at dry sites due to the different heat regimes.

Soil temperatures were recorded at depths of 1, 10, and at 100 cm (if no permafrost was present until this level). The dry sites show higher temperature values for the upper levels (1 and 10 cm) than the mesic spots, but the differences between these soil temperatures are on average greater at mesic sites (2.4°C) than at dry sites (2.1°C). This effect can be attributed to differences in the plant cover as well as to the different moisture contents of the surface layers.

On board the ship, preliminary chemical and microscopic analyses were performed. These analyses comprised determinations of soil colour (according to Munsell Soil Colour Charts), measurements of pH (CaCl₂), notes on occurring soil animals and algae as well as preliminary inspections of the microbial community, i.e, fungi, cyanobacteria and bacteria.

The pH (CaCl₂) values are generally below 7, although many sites showed basic and carbonatic bedrocks which showed strong reactions on acidification (1n HCl). Such reactions were monitored at different intensities at sites 3–9.

Observations concerning animals can only be given as an impression of direct observations, they are not quantitative. However, it is remarkable that nematodes were found at all places. In high latitudes and in fine material the animals were smaller in size. Samples from sites with dense plant cover (mesic sites) also showed animals of very different sizes. Most animals, however, ranged in length between 0.25–0.35 mm; larger animals of up to 1 mm were rare. The depth distribution also followed the main occurrence of litter and roots.

The microscopic inspections could not be fully completed due to lack of time at the end of this leg and bad conditions for microscopic observation while the ship was icebreaking. Hence, only a small part of this investigation can be presented here. Mostly, the soils showed a dominance of small sized bacteria, i.e., cocci: 0.2–0.5 µm and rods 0.5-1.5 µm, which can be regarded as typical sizes for polar regions. Larger forms of cocci and rods were rare and occurred only in small numbers where nutritional and environmental conditions seemed to be ideal, e.g., on Somerset Island (mesic site, 0–4 cm). The surface samples from Ungava also had few cyanobacteria and fungi, few diatoms and other green algae were observed on barren spots. A similar result was obtained from the surface samples from the mesic site on Melville Peninsula, although fungi became more rare. The dry site, however, showed many hyphae of fungi, but no algae; cyanobacteria were abundant. Barren soils from other places often showed a very diverse flora of diatoms. The surface soils of Somerset Island showed greater diversity of bacteria and typical forms of Arthrobacter were monitored. At the mesic site, cyanobacteria with heterocysts could be observed. Furthermore, large hyphae of fungi (probably basidiomycetes) were observed here. The dry site was much poorer and there were only a few small cyanobacteria; cocci shaped bacteria mainly dominated the entire community. Samples from Bathurst South (mesic) again showed a diverse algal flora, mainly diatomes of various sizes and shapes. Cyanobacteria occurred as uni-cellular cells, chains of cocci formed cells and filaments with sheaths. The dry site, again, was much poorer and only a few chains of cocci-formed cells could be observed.

Sub-samples from individual soil horizons were deep-frozen for further analyses of grain size distributions and contents of organic and inorganic matter. Samples from surface layers (0–2 cm), from the upper layer (2–6 cm), the layer close to the permafrost and other distinct horizons were collected for further analysis of microbiological properties in the laboratory at home. The data from these samples will comprise bacterial counts and biomass with respect to their size distribution as well as differentiations for cyanobacteria, fungi and soil algae.

Samples for determining root abundance and distribution were taken from all three ecotypes in co-operation with Dr. Esther Levesque; samples from wet sites were taken by Dr. Inga Svala Jonsdottir. The samples were taken either using a soil corer (d=5 cm, 1=10 cm) or, in stony and gravely soils, by digging small pits (10x10x10 cm). All samples were washed, sieved and sorted for roots on board ship, and prepared for further analyses in the laboratories at home. Sampling of soil surfaces for microbiological analyses and root sampling was continued by Dr. Anders Dahlberg on Leg 2.

Summary

Studies of soils and soil microbes were the focus of this project on the first leg of the Tundra Northwest 1999 expedition. Field studies focused on soil descriptions and included determinations of the active layer and soil temperatures. Samples of different layers were used for further descriptors such as soil colour and soil pH. All soils were classified as regards these properties in accordance with soil taxonomy. Further samples were taken for estimating the below-ground biomass of plant roots and for microscopic analysis. Surface horizons showed a great variety of different micro-organisms. Bacteria showed a typical size class distribution with small cocci and rods, which seems to be typical for polar environments. Organic soils also often showed high abundances of nematodes. Barren soils had a diverse flora of cyanobacteria and green algae, mostly diatoms.