Polish Polar Research

Skeletal remains of penguins from the Eocene La Meseta Formation (Seymour Island, Antarctica) constitute the only extensive fossil record of Antarctic Sphenisciformes. No articulated skeletons are known, and almost all fossils occur as single isolated elements. Most of the named species are based on tarsometatarsi (for which the taxonomy was revised in 2002). Here, 694 bones (from the Polish collection) other than tarsometatarsi are reviewed, and allocated to species. They confirm previous conclusions and suggest that ten species grouped in six genera are a minimal reliable estimate of the Eocene Antarctic penguin diversity. The species are: Anthropornis grandis, A. nordenskjoeldi, Archaeospheniscus wimani, Delphinornis arctowskii, D. gracilis, D. larseni, Marambiornis exilis, Mesetaornis polaris, Palaeeudyptes gunnari and P. klekowskii. Moreover, diagnoses of four genera (Anthropornis, Archaeospheniscus, Delphinornis and Palaeeudyptes) and two species (P. gunnari and P. klekowskii) are supplemented with additional, non-tarsometatarsal features. Four species of the smallest penguins from the La Meseta Formation (D. arctowskii, D. gracilis, M. exilis and M. polaris) seem to be the youngest taxa within the studied assemblage - their remains come exclusively from the uppermost unit of the formation. All ten recognized species may have co-existed in the Antarctic Peninsula region during the Late Eocene epoch.

The mathematical model that described the relationship between cell-count decay and storage time in fixed bacterioplankton samples from three Antarctic lakes of differing trophic status was determined after a one-year experiment. Bacterial density was estimated by epifluorescence microscopy. Cell count data fitted a negative exponential model in all three cases (p < 0.00001). However, the slopes of their curves were significantly different (p < 0.01), as well as the percentage of bacterial loss after a period of two months. This fact might be related to the limnological characteristics of the water bodies, though the individual genetic variability of their bacterioplankton should not be left aside. Original bacterial numbers in the samples could also be a reason of the differences observed in the pattern of decay in cell counts. Thus, applying a general decay function to any sample and assuming the idea that freshwater bacterioplankton samples can be stored for a two month-period before the bacterial counts decay, can lead to an erroneous estimation of bacterial numbers with direct consequences in ecological investigations.

This paper includes a check-list of Recent Svalbard marine ostracods based on published sources and on diploma theses as well as some new studies. This is the first study of this group of crustaceans from Hornsund. A total of 41 species belonging to 12 families were collected at 55 sampling stations from dredged sediments. Seven species are reported for the first time from the Svalbard Archipelago. Polycope orbicularis Sars is the most abundant species in the present fauna. Species compositions of Hornsund and the Liefdefjorden are seen to have the highest similarity (S = 50.6).

The fusulinid foraminifers of Schellwienia arctica (Schellwien, 1908) have been investigated from Polakkfjellet Mt., south Spitsbergen, and used as biostratigraphic marker for the latest Carboniferous earliest Permian strata of the Treskelodden Formation. A series of thin sections enable to investigate the internal structure and growth pattern of individual specimens. The observed variation of growth suggests dynamic environmental conditions at the investigated location and most likely over one-year long life span of this foraminifer.