Andrzej Tatur

Formation of abandoned penguin rookery ecosystems in the maritime Antarctic

Abstract Due to regional glacio-isostatic uplift of land during the Holocene period, a large number of penguin populations from several rookeries began to nest on the newly formed beaches and emerged rocks, leaving previously colonized higher cliffs. Chronology and extent of raised beaches, lichenometric age estimation of Usnea antarctica and radiocarbon-dating of guano and subfossil penguin bones in the abandoned nesting sites suggest the progress of the downward movement of many rookeries about 2500 years ago, accelerated during the last millennium, when wide bands of 4 to 6 m raised beaches were formed. Patterns of relic ornithogenic soil formation in the abandoned rookeries (focussed on leaching, erosion processes and humus horizon creation), as well as the succession of vegetation in the age sequence of abandoned nesting sites, were investigated in detail at Stranger Point, King George Island. The chemical composition of Deschampsia antarctica growing in the area of active, abandoned rookeries and in control sites provides direct and indirect evidence of current and past ornithogenic manuring on nutrition of vegetation.

A new species of fossil penguin from Seymour Island, West Antarctica

A new species of Early Tertiary fossil penguin from Seymour Island is described on the basis of tarsometartarsi from the collection acquired during the Argentinian-Polish field party of 1985. Palaeeudyptes klekowskii sp. nov. is bigger than earlier described species of this genus from the same locality. Information is given on the new collection of fossil penguin bones, a large part of which was found in one horizon of Unit III of the La Meseta Formation. The collection also includes much of the accompanying invertebrate and vertebrate fauna.

Stable carbon and oxygen isotope record in the Paleogene La Meseta Formation, Seymour Island, Antarctica

Stable carbon and oxygen isotopic relations have been analysed in brachiopod, gastropod, and bivalve fossils from the La Meseta Formation (Eocene-?early Oligocene), Seymour (Marambio) Island, West Antarctica. The results indicate a shift in δ 13 C by 6 permil beginning in the middle part of the Unit II of the formation. This shift may imply a change from a largely stratified to a vigorously mixed ocean. Such an interpretation is corroborated by changes in the elemental proportions in the shell material. Alternatively, the carbon isotopic shift may be regarded as reflecting a change in the local depositional enviornment. Such an interpretation agrees with isotopic data from the Weddell Sea, which do not confirm the pattern observed in the La Meseta Formation. In any event, the oxygen isotopic curve does not decline parallel to the carbon curve and may thus imply a considerable climatic cooling event. This effect is so profound that it might be interpreted as evidence for glaciation, especially when taking into account the fact that this phenomenon coincides with the well-known cooling trend throughout the Eocene. If this interpretation is correct, the hypothesized Glaciation may possibly be correlated with the Polonez Glaciation, the largest Cenozoic glaciation known in the Antarctic Peninsula sector. Alternatively, it may be regarded as a local phenomenon, predating development of the icesheet.

Holocene environmental change in a marine-estuarine-lacustrine sediment sequence, King George Island, South Shetland Islands

Sedimentological features and cluster analysis of diatom assemblages were used to investigate a local Holocene prograding sequence of marine-estuarine-lacustrine sediments. It consists of upward finning and thinning sediment cycles formed at the mouth of a meltwater stream during regional isostatic uplift, which followed early Holocene deglaciation and marine inundation events. The sequence begins in the lower Holocene sublittoral sand (marine diatoms and abundant molluscs) overlying, with a transgressive base, the deltic (?) clastic sediment marking probably one of the pre-Holocene interglacial periods (index diatom Actinocyclus ingens suggests an age >0.62 Ma). The lower Holocene marine sand was truncated by middle Holocene gravity flows, bearing volcanic ash. They were deposited in a high energy estuarine environment (brackish diatoms). The beach subsequently formed separated the estuary from the sea and changed it into a freshwater lake. Accumulation of moss and gyttja, containing a freshwater diatom assemblage, marks the final late Holocene stage of this coastal sedimentary sequence, which can be considered as typical for deglaciation periods in the maritime Antarctic.

A new Antarctic foraminiferal species for detecting climate change in sub-Recent glacier-proximal sediments

Abstract Cribroelphidium webbi sp. nov. is the only adequately described sub-Recent elphidiid foraminifer from Antarctica. In Admiralty Bay (King George Island, South Shetland Islands), it is found at several locations within inner fiord setting at water depths between 33 and 165 m, but most commonly shallower than 100 m. In outer basins this foraminifer is absent. In the cores analysed, C. webbi sp. nov. is present in well-constrained sub-Recent horizons that are clearly related to climate warming and deglaciation. These horizons represent a diachronous facies marker rather than a single stratigraphic layer. Cribroelphidium webbi sp. nov. shows clear association with retreating tidewater glaciers, therefore it is an important sensitive glacier-proximal indicator. It appears that it shares similar ecologic affinities with Cribroelphidium excavatum clavatum, which is widely distributed throughout the Arctic.

Records of Holocene Environmental Changes in Terrestrial Sedimentary Deposits on King George Island, Antarctica; A Critical Review

In this study we discuss some problems that emerged from paleolimnological and paleonto- logical investigations of terrestrial Holocene ecosystems on King George Island (South Shetland Islands) conducted by an Argentine-Polish research group. Biological and geochemical markers commonly used in standard analytical procedures are considered insufficient in tracing overlapping records of past environ- mental changes preserved in peat banks, lake sediments and ornithogenic remnants. Records that might be explained by predictable natural events (related to glacio-isostatic uplift of land), roughly predictable events (ecological succession), or unpredictable events (volcanic eruptions or accidental destruction of aquatic moss) may overlap or interfinger one with another providing that signals of regional and/or global climatic changes, are hardly identifiable. A more sophisticated and more selective methods are recommended to do discrimination between records of local and regional/global processes in studies on Holocene climatic his- tory of the South Shetland Islands.

The first record of fossil penguins from East Antarctica

Abstract This paper presents the first fossil penguin from East Antarctica, and the only one known south of the Antarctic Circle. It is represented by two well-preserved elements of the wing skeleton, humerus and radius, obviously assignable to the extant genus Spheniscus. They were found in the glaciomarine succession of the Fisher Bench Formation (Fisher Massif, Prince Charles Mountains, Mac. Robertson Land), which was dated using Strontium Isotope Stratigraphy to be Late Miocene in age (10.2 Ma). They are only slightly younger than the oldest remains undoubtedly attributable to this taxon. The X-ray diffraction and Fourier Transform Infrared Spectroscopy indicate diagenetic alteration of the original bone bioapatite under dominantly marine conditions. The Late Miocene was a period of ice margin retreat and marine incursion into the Lambert embayment that followed Middle Miocene cooling of the Antarctic climate. The fossils strongly suggest that variable climatic and environmental conditions in East Antarctica may have been an important factor in the evolution of penguins there during the Neogene.

Sedimentary Cores from Mascardi Lake, Argentina: A Key Site to Study Elpalafquen Paleolake

Sedimentary cores from Mascardi Lake, as well as outcrops, have been studied to reconstruct late Pleistocene and Holocene environmental conditions in northern Patagonia, Argentina. The Mascardi Lake sequence is a key-site for understanding such conditions, providing evidences of ice retreat, volcanic activity and important sedimentation changes. A significant environmental change occurred around 13 ky BP when the great lake named Elpalafquen became several small basins and some of the present lakes from northern Patagonia started to get their current features. The Mascardi Lake occupied a marginal position, close to the ice front at the western side of the paleolake.

Short Note: An ibis-like bird from the Upper La Meseta Formation (Late Eocene) of Seymour Island, Antarctica

Ibises are a group of medium- to large-sized, mainly wading birds in the family Threskiornithidae (Aves: Ciconiiformes; see also discussion in Mayr 2002). They are known from all the continents except Antarctica, though one species breeds as far south as Tierra del Fuego (del Hoyo et al. 1992, p. 499). The oldest fossil bones (including skull elements) attributed to ibises are those of Rhynchaeites messelensis Wittich, 1898 from the Middle Eocene of Messel, Germany (Peters 1983, Mayr 2002). Another supposed member of this group is the Pondaung bird from the late Middle Eocene of Myanmar (formerly Burma) represented solely by an incomplete tibiotarsus (Stidham et al. 2005, fig. 2). The taxonomic position of Minggangia changgouensis Hou, 1982 from the Late Eocene of China (Hou 1982) was recently questioned by Stidham et al. (2005, p. 183). Here, we present a partial bill from the Eocene La Meseta Formation (Seymour Island, Antarctica) which most closely resembles that of ibises.

The effect of biochanin A on the chlorophylls and carotenoids content in the alga Chlorella vulgaris Beijerinck

The present study was undertaken to determine the influence of biochanin A, isoflavone characterised by estrogenic activity, upon the content of chlorophylls and carotenoids in the cells of green alga Chlorella vulgaris Beijerinck (Chlorophyceae). On the 6th day of cultivation under the influence of 10−6 M biochanin A exerted the greatest biological activity and the most stimulating effect on the analysed parameters: growth of the alga expressed by the cells number and the content of photosynthetic pigments in them. The total content of carotenoids was stimulated on the 6th day of experiment in the range of 197 % but during the 9th day only in 179 % in comparision with the control group (100 %). At the same time content of carotenes increased to the level of 123 – 119 % and xanthophylls to 208 – 178 %. Among the carotenes, β-carotene was characterised with the 3.7 times higher content in regard to the content of α-carotene on the 6th day of cultivation and during the 9th day — the 5.7 times domination. The content of xanthophylls that contain two atoms of oxygene in molecule (oxygen — poor xanthophylls) was intensively stimulated in the range of 224 %. Moreover, the oxygen — rich xanthophylls content reached the value 179 % when compared to the control. The greatest stimulation of the content of chlorophylls and its isomers was observed during the 3rd day of cultivation of Chlorella vulgaris when it rose up to 166 % and to 156 % on the 6th day. The content of chlorophyll b and its isomers was stimulated in 181 % on the 6th day of culture and 155 % during the 9th day of algal culture. The evidence on the stimulating effect of biochanin A as the main representative of isoflavones on the growth and content photosynthetic pigments in eucaryotic alga C. vulgaris was demonstrated in these studies.