This is the first detailed study of the distribution of mosses and lichens at Alexandra Mountains and Rockefeller Mountains, Edward VII Peninsula, Antarctica. A total of 418 samples was collected on 21 nunataks in the summer of 1987–1988. Lichens included 44 taxa, bringing the total known from Edward VII Peninsula to 50. Ten lichen species were new records for the Continental Antarctic zone, whilst only six were endemic to that zone. There were six species and one variety of moss, bringing the total known from Edward VII Peninsula to seven species and one variety. These included the first record of a species of Orthotrichum in Continental Antarctica. Two other species and a variety were new records for Edward VII Peninsula. Overall, the flora was species rich for a Continental Antarctic region and was comparable with the species-rich sites of Botany Bay and Kar Plateau, which are at approximately the same latitude (77°S) in southern Victoria Land. This rich flora was probably supported by a reliable summer water supply from melting snowfall and snowdrift and by the range of microenvironments at nunataks with different degrees of nutrient enrichment from nesting birds.

Eleven aerobic heterotrophic bacteria isolated from soil samples taken at c. 1800 m altitude from La Gorce Mountains, Antarctica, were characterized in terms of carbon source utilization, enzymatic activities and tolerance to environmental stressors. The bacteria typically formed pigmented colonies on agar plates and were initially observed on media designed for isolation of algae and cyanobacteria. The bacteria were purified and assigned to the Actinobacteria, Bacteroidetes or Proteobacteria divisions following 16S rRNA gene sequence analysis. While some of the isolates are most likely to belong to the genera Arthrobacter or Brevundimonas, others may belong to novel genera or species. The Gram-positive Actinobacteria used the widest range of carbon sources for growth. Brevundimonas P7 produced lipases, phosphatases, proteases and glycosyl-hydrolases. The Gram-positive bacteria were more tolerant to freeze-thaw than the Gram-negative isolates. No isolates survived more than 10 minutes ultraviolet irradiation. All isolates were unaffected by 24 h desiccation. This study adds to knowledge of the bacterial diversity of soils from high altitude (1800 m), high latitude (86°30'S) locations within Antarctica.

Specimens of Prasiola collected from habitats not experiencing nutrient enrichment from birds are considered to be P. calophylla. The alga has three distinct growth forms; uniseriate filaments, narrow ribbons and expanded sheets. Reproduction is by aplanospores and fragmentation of the thallus. The known Antarctic distribution is disjunct with only two records outside Victoria Land. However, it is widespread in the latter region. The alga is absent from areas where there are high salt concentrations in waters and soils. Elsewhere it is common in streams and on water-flushed ground as well as occurring on terminal ice-faces of glaciers and as chasmoendolithic growths. Ribbons are found mostly on the lower surfaces of stones, and uniseriate filaments on the exposed surfaces of the stream beds of seasonal melt streams. Expanded sheets occur in less vigorous water flows. There is a need for further culture and field studies in order to understand the factors which control morphological development and distribution patterns.

The survey concentrated on algal communities but also gathered information on mosses, lichens and microfauna. All 23 nunataks in the Rockefeller and Alexandra mountains (77°00′–78°30′S, 152°–154°W) were visited, including ones both with and without nutrient enrichment from bird colonies. Over 30 species of algae were recorded with Cyanobacteria and Chlorophyta dominant as in other regions of continental Antarctica. Diatoms were not found. The most frequent algae were Cyanothece aeruginosa, Gloeocapsa spp., Oscillatoriaceae, Nostoc sp., Pseudococcomyxa simplex, Stichococcus bacillaris, cf. Desmococcus vulgaris, Prasiola crispa and Prasiococcus calcarius. Although lichens were the most visually prominent vegetation, free-living algae occurred in the widespread ‘non-aquatic’ habitats as epilithic, chasmoendolithic and edaphic communities as well as being epiphytic on the sparse moss cushions. Aquatic habitats were few and there were only three small ponds on or adjacent to nunataks. On ablating ice, cryoconite ponds contained Homoeothrix cf. rivularis, recorded for the first time in Antarctica. Preliminary identifications show 23 species of lichens and six species of mosses. No mites and collembola were seen. Samples contained testate amoebae, ciliate protozoa, rotifers and tardigrades but no nematodes.

Field populations of Oscillatoriales, from fresh and saline lakes and ponds, and from terrestrial habitats, are characterised on the basis of their morphology and morphometry. Fifteen morphotypes are recognized principally from the following characteristics; cross-sectional shape of the trichome, presence or absence of a calyptra on the apical cell, occurrence or otherwise of numerous trichomes within a common sheath, and trichome width distribution. Where possible morphotypes are assigned to traditional species described by earlier investigations of algae in the Ross Sea region and a reassessment is made of the early descriptions, in some cases using material from the identical locations to the original collections. The following traditional species are described; Lyngbya murrayi, Microcoleus vaginatus, Oscillatoria deflexa, O. koettlitzi, O. priestleyi, O. sancta, Phormidium autumnale and P. subproboscidea. Intraspecific morphotypes of M. vaginatus, O. priestleyi and P. autumnale are recognised on the basis of trichome width. A new species and variety of Crinalium (Crow) Winder, Stal & Mur, a genus characterized by flattened trichomes, are described from cryoconite ponds on glaciers. C. glaciale sp. nov. possesses wide, straight trichomes in contrast to C. glaciale var. helicoides nov. var. in which trichomes are narrower and helically coiled.

Two species of lichens, six cyanobacteria, one diatom, 10 chlorophytes and two mycelial fungi were found at La Gorce Mountains (86°30′S, 147°W) at an altitude of about 1750 m. The lichens Lecidea cancriformis and Carbonea vorticosa occurred at a single site which is the most southerly record of lichens. Thousands of small ponds covered extensive ice-cored moraine. Nine ponds sampled had about 30 cm of ice overlying about 26 cm of water and contained algal mats dominated by Phormidium autumnale and cf. Leptolyngbya fragilis. The very low conductivity waters had high nitrate and low dissolved reactive phosphorus concentrations. Of 124 soil samples, five contained visible algae. In 32 there were only microscopic growths but no algae were detected in 87 samples, possibly because of lack of water for much of summer. A visible mat dominated by Hammatoidea normanni occurred in a rock fissure at the lichen site. At Price Bluff, green patches of Desmococcus cf.olivaceus, up to 20 cm2, were scattered over the moraine. Growths were revealed at the soil–ice interface when overlying soil up to one centimetre thick was removed. It is suggested that although dispersal of algae from local populations may be readily achieved establishment of populations is a rare event outside the pond environment.