Qualitative and quantitative composition of phytoplankton of the Olaf
Prydz Bay (Indian Ocean, East Antarctica) was determined on the basis of 49 samples collected at 34 sampling stations during the period from the 15th to 24th February 1969. Altogether 59 taxa of algae were identified — among them: 57 taxa of the class Bacillariophyceae, 1 species of the class Chrysophyceae and 1 genus of the class Dinophyceae. Species occurring most frequently and most abundantly in the Olaf Prydz Bay are diatoms: Thalassiothrix antarctica, Chaetoceros criophilus, Nitzschia curta, Rhizosolenia alata. At some stations Chaetoceros dichaeta occurred in great numbers. A decrease in phytoplankton numbers in the areas south of 67 S is associated with the lack of neritic algae among dominant species.
The algal microfossil Bolboforma reticulata Daniels and Spiegler is recorded from the Oligocene-Miocene glacio-marine sediments of King George Island, South Shetland Islands, Antarctica. The record extends the geographic extent of the species to Antarctica.
This work presents the results of a study whose aim was to determine the influence of algal blooms on precipitation of heavy metals. The scope of the study covered culture of a mixed population made up of Scenedesmus and Pseudokirchneriella algae in experimental conditions and initiating a metal biosorption process with the use of culture biomass by administering ions of Zn(II) and Ni(II). The process was controlled by assessing the level of biosorption of metals entered at a one-off basis in the form of Zn(II) and Ni(II) salts or in the form of mixture of both ions, in comparison to the control sample, at different exposure times (2 hours and 24 hours). The presence of metals was determined both in the biomass and in the culture medium. The presented results of the study confirm the effectiveness of Chlorophyta in the process of zinc and nickel biosorption. A phenomenon of competitiveness between the metals was observed when they were administered at the same time.
During the spring of 1998 sympagic algae and meiofauna were studied in Ross Bay on the western coast of the Kane Basin between Ellesmere Island and Pim Island (Canada). Ice samples were collected by ice coring and the lowermost 2 cm sections were analysed. The sea-ice flora was composed of 59 taxa and was dominated by Nitzschia frigida, Navicula pelagica, Fragilariopsis oceanica and unidentified flagellates (over 60% of total number). Abundance of algae ranged from 1×109 to 3×109 cells per square meter. Sea-ice meiofauna was composed of Nematoda and Harpacticoida and was strongly dominated by nematodes (99.76%). Total sympagic meiofauna abundance ranged from 37.5×103 to 146.1×103 ind. and biomass from 2.88 to 8.83 mg C per m2. There was no clearly marked patchiness in the horizontal distribution of sympagic algae and meiofauna.
We report on the photoresponse dependence on the terahertz radiation intensity in ALGaN/GaN HEMTs. We show that the ALGaN/GaN HEMT can be used as a THz detector in CW and in pulsed regime up to radiation intensity of several kW/cm2. The dynamic range in the pulsed regime of detection can be more than 2 decades. We observed that the photoresponse of the HEMT could have a compound composition if two independent parts of the transistor are involved in the detection process; this result indicates that a more simple one channel device may be preferable on the detection purpose.
The occurrence of 18 species of algae was stated in the investigated region. Among them the following were predominant: Himantothallus grandifolius, Desmarestia menziesii, Cystosphaera jacqninotii, Ascoseira mirabilis. Leptosomia simplex. Adenocystis utricularis. Monostroma hariotii, Iridaei: obovata, Hildenbrandia lecunnellieri, Plocamium coccineum and Phycodrys antarctica. Vertical stratification of the distribution of three singled out communities of algae was observed downwards to the depth of 90 m, which is the limit of the occurrence of the algae in the Bay. The process of decomposition depends on the place where it occurs, the kind of the thalluses and the season of the year. The quickest decomposition of algae was observed on the shore, in the summer and spring. The total quantity of algal matter washed ashore along 15.8 km of the coast line of Admiralty Bay, during the period between February and October 1979, was estimated at 279 metric tons of dry weight matter. From this quantity, in result of decomposition of the algae on the shore, 75 tons of the matter were released during an average time of 12 days. The remaining 204 tons of partially decomposed algal matter are driven by winds farther inshore or into the waters of the Bay or remain ashore among the stony rubble.
In surface horizons of Gelic Regosols. Gelic Gleysols and Gelic Cambisols from 5 sites in Kaffiöyra. 26 taxa of blue-green algae have been determined. Species of the genera Gleocapsa, Schizothrix, Tolypothrix and Calothix were the most common. In Gelic Regosols blue-green algae formed during the last 100 years the 0.5 cm thick horizon A, containing 8.6% of humus.
The use of phytoplankton as an indicator of water pollution is a promising tool for assessment of water quality. The purpose of this study was to determine whether diversity indices, including the species richness and diversity of phyto-plankton, could be used for reliable assessment of water quality in the Wadaslintang Reservoir in Indonesia. Surveys were conducted monthly at eight sites, from July 2019 to October 2019. Phytoplankton was collected during the day at 10:00 until approximately 15:00 in the euphotic zone. The parameters investigated were species richness and the abundance of phytoplankton, as well as water quality parameters listed in Government Regulation Number 82 of 2001. The level of pol-lution was represented biologically by the Shannon–Wiener diversity index and physicochemically by the STORET (stor-age and retrieval of water quality data) index. Moreover, the two indices were compared to determine whether a particular diversity index was more effective for assessment of this reservoir. The results showed that during the dry season, 22 taxa of phytoplankton were present, belonging to Cyanophyta, Chlorophyta, Chrysophyta, and Euglenophyta. During the wet season, 29 taxa were found, belonging to Cyanophyta, Chlorophyta, and Chrysophyta. Based on the Shannon-Wiener index and STORET index, water quality was better during the wet season than during the dry season. The results of water quality assessment using both indices were consistent, but the diversity index was a more sensitive indicator of pollution levels. Therefore, the Shannon–Wiener index is a useful tool for assessment of water quality in the Wadaslintang Reservoir.
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.
Eight samples of the ice algae were collected from the annual ice in Tikhaia Bay, Hooker Island, Franz Josef Land. Species composition included 58 diatoms (and some Navicula, Nitzschia and other Pennatophyceae unidentified species), 2 dinoflagellates, 2 chrysophyceans, 1 chlorophycean, 1 cyanophycean and possible dinoflagellate and chrysophycean cysts. The maximum quantity was 132300 cells/l. In 4 samples Aulacoseira granulatu prevailed, in other samples Nitzschia frigida, N. cylindrus, Rhizoclonium sp. and dinoflagellate cysts dominated. Xanthiopyxis polaris found by Gran (1904) in Arctic sea ice and referred to the diatoms is, possibly, the dinoflagellate cyst. On the whole, the ice community consisted of benthic and planktonic-benthic species of mainly marine and brackishwater-marine pennate diatoms, their resting stages, freshwater unicellular algae and marine chlorophycean.
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.
Some 20 samples of bottom sediments of freshwater lakes collected in the Antarctic Thala Hills oasis (Enderby Land) were soaked in laboratory cultures. 85 taxa of algae were identified in these cultures: Cyanophyceae — 54, Chrysophyceae — 1, Xanthophyceae 10 and Chlorophyceae — 20 taxa. Most of these taxa are illustrated.
A map was made of the distribution of macroalgae groupings in shallow waters of Admiralty Bay. The map was plotted on the basis of analysis of color reversal air photograph taken from a helicopter. A significant agreement of the results of the pictures analysis with the field studies was found. Also a number of areas not covered by field studies was determined as the ones of probable occurrence of macroalgae. A detailed map of distribution of four distinguished forms of macroalgae groupings was plotted for a small area in the region of Shag Point. Each of these forms is characterised by different association of algal species.
The paper presents descriptions and illustrations of Anthracoporella spectabilis Pia (Dasycladaceae) and Palaeoaplisina laminaeformis Krotov (Hydrozoa) from the Treskelodden Formation (Lower Permian, Sakmarian) of the Hornsund area (Treskelen, Urnetoppen), and Chaetetes arcticus sp. n. (Demospongiae) from the „Wordiekammen Limestone" (Pernio — Carboniferous) of the Isfjorden area of the southern and central part of Spitsbergen. A. spectabilis and P. laminaeformis common in the Hornsund area are also known from the northern Ural Mts. and Timan.
It appears from the analysis of the chemical composition of macroalgae of the Antarctic: Adenocystis utricularis and Himantothallus grandifolius (brown algae), Leptosomia simplex (red algae) and Monostroma hariotti (green algae) that the examined algae, brown algae in particular (mainly Adenocystis utricularis), are rich in mineral components, primarily: sodium, potassium, hologens, and structural polysaccharides. Organic substances, such as: proteins, amino acids, lipids, fatty acids, saccharides reduction, chlorophylls and carotenoids, occur in the analysed algae in quantities much smaller in comparison with taxonomically similar macroalgae derived from marine environment having more favourable hydrochemical and climatic conditions.