Cold tolerance of Antarctic terrestrial nematodes in the McMurdo Sound region

A survey of the nematode fauna associated with moss and algae growth from terrestrial sites on Ross Island and the McMurdo Dry Valleys was conducted. A total of 6 species were identified and maps were drawn showing the distribution of each species in the McMurdo Sound region. Cultures of Panagrolaimus davidi, Plectus antarcticus and Plectus frigophilus were established on nutrient agar plates. Experiments were conducted to determine the mechanisms of cold tolerance in P. davidi. The supercooling point of nematodes was tested using a thermoelectric cooling stage. Samples were collected from: Crater Hill on the lower slopes behind Scott Base, algal growth associated with runoff from the northern penguin rookery at Cape Bird, the path leading to the Cape Bird hut, the soil near runoff from the northern penguin rookery at Cape Bird, algal and moss from the Kibble Valley SSSI, the melt water around Pony Lake at Cape Royds, areas of moss growth in the vallies north of Pony Lake, melt water of Barclay Glacier in the Dry Valleys, areas of red or orange algal growth in the meltwater and around the edge of several small ponds in between Lake Vanda and Lake Bull, extensive areas of algal growth around the edge of Lake Canopus near Lake Vanda, algal growth in Drift Stream near Lake Fryxell and samples were also received from the Darwin Mountain regions. Nearly 10 years later, cultured nematodes of P. davidi were used to compare the freezing tolerance of samples of this nematode collected fresh from the field. Nematodes were collected from extensive areas of algal growth located below Robbers Roost, Cape Bird. Freezing tolerance was established by observing the freezing of nematodes on a cold microscope stage and then recording their recovery after the freezing event. The male:female sex ratio of nematodes in the field was compared with cultured nematodes (all cultured nematodes were female), and samples of female nematodes were taken from the field and compared with cultured females using standard techniques.