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Number of results: 5
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Abstract

The chlorophyll a content was measured at 62 oceanographic stations. At each station samples were collected from eight standard depths between the water surface and 150 m. Integrated values (chlorophyll α mg/m2) are used in the presentation of the results and discussion. The recorded quantities of chlorophyll α were rather high, amounting to as much as 634 mg/m2. The areas with high chlorophyll a content (> 200 mg/m2) were located in the region of the Anvers Island and Brabant Island, on the shelf around Joinville Island and opposite the Antarctic Sound, close to Clarence Island and beyond the regions recommended in the BIOMASS-SIBEX programme to the east and south of the South Orkney Islands. In the acetonie extracts of photosynthetizing pigments large quantities of phytoxanthin were found using the TLC method, what precludes the use of the Lorenzen method for determination of chlorophyll α and its degradation products.
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Abstract

Coarse-scale studies on chlorophyll a distribution in a region covering the Scotia Front zone showed an increased chlorophyll content and its deeper distribution at stations situated in the frontal zone. The sources of chlorophyll α were probably both the phytoplankton released from melting ice as well as spring bloom.
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Abstract

The major aim of the study was to identify the relationships of photosynthetic pigments with elemental contents of plants exposed to various ambient air conditions. Lolium multiflorum L. plants were exposed at five sites varying in environmental characteristics, including potential air pollution levels. The effect of air pollution by trace elements on plants was examined. Selected trace elements (Pb, Cd, As, Ni, Cr), some macro-elements as well as chlorophyll content were measured after each of four series. The graphical visualization revealed groups of sites with similar response of elements and chlorophyll contents. Sites located outside the city were grouped into one, and two urban sites were grouped into another. The trace element contents were relatively low and, excluding Ni and As, did not reach toxic levels in dry mass of leaves. However, some relations could be noted, which indicates the sensitivity of the photosynthetic process even at low levels of trace elements in ambient air. Chlorophyll b was found to be more sensitive to most of the analyzed trace elements than chlorophyll a. The results revealed chlorophylls, K and Na as indicators of plant stress caused by trace elements present in ambient air, even at relatively low levels.
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Abstract

Chlorophyll a content and the density and species composition of algae were determined in drifting sea ice north of the Elephant Island (between 54-56°W and 60°30'—61°00'S) at the end of October 1986. In yellow-brownish pieces of brash ice the amount of chlorophyll α was on average 203.5 ± 149.9 mg m-3 at the density of algal cells of 255.7+137.8-103 in cm3. In not visibly discoloured ice the respective values were about 80 times lower, and in surface water about 700 times lower. 69 algal taxa were recorded in the samples, almost all of which were diatoms. Nitzschia cylindrus dominated in all the samples. A comparison of species composition in the investigated habitats revealed that the highest species similarities occurred between samples collected in discoloured ice, lower in the uncoloured ice and the lowest ones in water.
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Abstract

At the northern border of pack ice the study on chlorophyll a content, density of cells, species composition and domination in samples from the drifting ice floes and from brash ice was carried out. 102 taxa of algae were found in the pack ice. In the study area algal taxa were rather uniformly distributed. In different ice layers the qualitative composition of diatom assemblages was similar and usually the diatom Nitzschia cylindrus was dominant and most frequent. Chlorophyll a content (from 0.12 to 334.5 mg m-3) and the density of cells (from 0.3 to 362 x l0 6 cm) varied strongly in various habitats. Ice floes near the northern pack ice border contained low values of chlorophyll a (mean value 0.50 ±0.28 mg m-3) . However, brash sea ice originating from ice floes, contained 142.4 ±117.5 mg m-3 of chlorophyll α in visibly discoloured and 30.1 ±24.3 mg m~3 of chlorophyll α in not visibly discoloured parts on average. The range of chlorophyll α content and the presence of characteristic species allow to distinguish brash sea ice infiltration assemblage of diatoms.
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