| 1. |
- Abrahamsson, Katarina, 1957, et al.
(author)
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Air-sea exchange of halocarbons: the influence of diurnal and regional variations and distribution of pigments
- 2004
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In: Deep-Sea Research Part Ii-Topical Studies in Oceanography. - : Elsevier BV. - 0967-0645. ; 51:22-24, s. 2789-2805
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Journal article (peer-reviewed)abstract
- Diurnal cycles of halocarbons, except methyl bromide and methyl chloride, were observed at six 24-h stations occupied in three different regions, the Summer Ice Edge, the Winter Ice Edge, and the Antarctic Polar Front, in the Atlantic sector of the Southern Ocean during a Swedish-South African expedition in 1997/1998. The diurnal cycles contained three phases; a productive phase, a phase of losses and a phase with steady state. The duration of the different phases varied for the different stations as well as for individual compounds. The measured production and losses of organo-halogens in the Antarctic Ocean based on values from each station, were in the order of a few to hundreds of Tg yr(-1). Bromochloromethane, tribromomethane, trichloroethene and diiodomethane were the four compounds found in highest concentrations throughout the investigation, and they were found to be the major contributors of organohalogens. Only the presence of the photosynthetic pigment 19'-hexanoyloxyfucoxanthin, biomarker pigment of haptophytes, could explain some of the variations in the distribution and production of halocarbons, and then only for iodinated compounds. The flux of organo-halogens from the oceans to the atmosphere was estimated in two ways, either based on calculations according to models or based on the measured concentrations. Large discrepancies were found, which could not be explained by chemical or biological degradation or adsorption to particles. This investigation, therefore, shows the need for assessing the rates of degradation and the air-sea exchange more accurately. (C) 2004 Elsevier Ltd. All rights reserved.
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| 2. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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A new species of Craspedostauros (Bacillariophyceae) from the west coast of Sweden, with taxonomic and ecological notes on Craspedostauros laevissimus
- 2024
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In: Botanica Marina. - 0006-8055 .- 1437-4323. ; 67:1, s. 51-60
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Journal article (peer-reviewed)abstract
- Since its separation from Stauroneis in 1999, several new species of Craspedostauros were discovered in a variety of habitats and geographic locations, adding morphological and phylogenetic data to the investigations of the genus. In a survey of littoral diatoms of Sweden, both on the west and east coasts, two epiphytic stauros-bearing species were encountered and assigned to Craspedostauros following the characteristic features of this genus, including the possession of a stauros narrower than the central area and cribrate areolae. One species is described as new to science; Craspedostauros lateralis sp. nov., and the other is of uncertain identity but bears morphological similarity to C. laevissimus. Caspedostauros lateralis is a marine epiphytic species found in the west coast of Sweden, off Gothenburg city. Based on light and electron microscopy, a detailed description of the morphological and ultrastructural features of these species is given and a comparison of the distinguishing characters with allied species is discussed. Some ecological data and the occurrence of associated species on the host macrophyte are provided.
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| 3. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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COCCONEIS POTTERCOVEI SP NOV AND COCCONEIS PINNATA VAR. MATSII VAR. NOV., TWO NEW MARINE DIATOM TAXA FROM KING GEORGE ISLAND, ANTARCTICA
- 2010
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In: Diatom Research. - 0269-249X. ; 25:1, s. 1-11
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Journal article (peer-reviewed)abstract
- Details of two new small marine taxa of the genus Cocconeis Ehrenberg are described; C. pottercovei sp. nov. and C. pinnata var. matsii var. nov., which were observed as epipelic and epiphytic in Potter Cove, King George Island, Antarctica. Descriptions are based on both light and scanning electron microscope observations. C. pottercovei belongs to the group of Cocconeis taxa that bear very short and marginal striae on the rapheless valve while C. pinnata var. matsii belongs to the C. costata Gregory complex. They are mainly differentiated from the other similar taxa by stria number, stria arrangement and structure on both raphe and rapheless valves. A comparison with closely resembling taxa is given.
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| 4. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Entomoneis annagodheisp. nov., a new marine diatom (Entomoneidaceae, Bacillariophyta) from the west coast of Sweden
- 2020
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In: Diatom Research. - : Informa UK Limited. - 0269-249X .- 2159-8347. ; 35:3, s. 269-279
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Journal article (peer-reviewed)abstract
- The genusEntomoneisincludes diatoms with an elevated bilobate keel, a sigmoid raphe canal and numerous girdle bands. It is known to inhabit various environments, from freshwater to marine, both plankton and benthos. During a phytoplankton investigation in the Kungalv estuary on the west coast of Sweden, we observed numerous cells belonging toEntomoneis. Further morphological investigations performed with light and electron microscopy allowed us to describeEntomoneis annagodhei, sp. nov., with a unique set of morphological characters. Most importantly, a still undocumented character proved to be an oblique transapical fascia across the centre of the valve. Other distinctive features of this species are a pronounced raphe canal with dense raphe fibulae, very fine striation, resolvable only with electron microscopy, external lanceolate slit-like opening of the central nodule, and fine, linear to undulate external ridges running more or less parallel and adjacent to the raphe and valve margin. The morphological characters and morphometry are discussed in comparison with similar taxa. Our results contribute to the under-appreciated diversity ofEntomoneis, especially inhabiting the marine plankton.
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| 5. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Entomoneis grisslehamnensis, a New Diatom (Bacillariophyceae) from the Baltic Coast of Sweden with taxonomic and ecological notes on Entomoneis paludosa (W. Smith) Reimer
- 2023
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In: Diatom Research. - 0269-249X. ; 38:1, s. 55-68
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Journal article (peer-reviewed)abstract
- The diatom genus Entomoneis includes species with panduriform frustules characterized by a bilobate, elevated keel, sigmoid raphe canal and numerous open, porous girdle bands. During a phytoplankton survey along the Baltic coast of Sweden, we observed numerous Entomoneis cells, some belonging to the well-known Entomoneis paludosa, while others remained unknown. Morphological and ultrastructural studies of the unknown species were performed with light microscopy (LM), scanning (SEM) and transmission (TEM) electron microscopy, and revealed a unique set of morphological characters. Live cells of Entomoneis grisslehamnensis sp. nov. contain one plate-like plastid and show various degrees of torsion about the apical axis. Microscopic features of cleaned frustules are discussed in comparison with similar species. Most importantly, every 2nd to 5th virga is strongly elevated, uniseriate striae are composed of quadrangular areolae with finely perforated hymenes; the winged keel with a discernible raphe canal is structurally strengthened by raphe fibulae with a flattened wing area, and the main part of the valve bulges towards the margins; striation is decussate on the wings and there is one row of raphe canal areolae at the central area. In addition to describing this new species of an underappreciated, yet cosmopolitan diatom genus, we contribute to the taxonomy of E. paludosa with LM, SEM and TEM details, some of which were not sufficiently noted in original descriptions or re-examination of type material and other specimens made by Dalu et al. [2015. A re-examination of the type material of Entomoneis paludosa (W. Smith) Reimer and its morphology and distribution in African waters. Fottea 15: 11-25] and Long et al. [2022. Ultrastructure of three species of Entomoneis (Bacillariophyta) from Lake Qinghai of China, with reference to the external areola occlusions.
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| 6. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Fallacia fawensis sp. nov., a new brackish water diatom (Bacillariophyceae) from Southern Iraq
- 2022
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In: Phytotaxa. - : Magnolia Press. - 1179-3155 .- 1179-3163. ; 550:1, s. 71-78
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Journal article (peer-reviewed)abstract
- The diatom genus Fallacia includes species having a conopeum which is a perforated thin sheath of silica lying along the apical axis on the external valve face and a hyaline lateral area in the internal valve face. In surveying the benthic diatoms of Basra, a new small brackish water species, Fallacia fawensis was found associated with fine-grained substrata on the western bank of Shatt Al???Arab River, Southern Iraq. This epipelic species is described based on light and scanning electron microscopy and characterized by having a porous conopeum covering the area between raphe sterna and mantle, narrow elongated marginal striae, and a structure similar to lateral hyaline areas in the valve internal side. The terminal raphe endings on the external valve face, below valve apex, the raphe sternum inner margins come close to each other, blocking raphe canal but leaving a lacuna-like thin groove for connection with the deflected upper part of the open raphe canal. These features separated this species from allied taxa of the genus and also from closely related genera, Pseudofallacia and Germaniella. Notes on the ecology and distribution of the new species as well as the associated diatom taxa are provided.
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| 7. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Gomphonemopsis ligowskii, a new diatom (Bacillariophyceae) from the marine Antarctic and a comparison to other Gomphonemopsis
- 2018
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In: Diatom Research. - : Informa UK Limited. - 0269-249X .- 2159-8347. ; 33:1, s. 97-103
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Journal article (peer-reviewed)abstract
- A new marine diatom, Gomphonemopsis ligowskii, is described. Gomphonemopsis ligowskii was found as an epiphyte on the brown macrophyte, Desmarestia anceps, collected from King George Island, Antarctica in January 2016. This species is the first of the genus described from a polar region. It is a small and relatively rare taxon that is characterized by its unique shape and the presence of uniseriate striae, composed of round poroidal areolae on its valve face. The striae are arranged in parallel rows on either side of the axial area, and a row of rounded areolae on both sides of the valve mantle is confined to the wider part of the valve (headpole). A description of valve ultrastructure as well as a comparison with related taxa are provided.
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| 8. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Marine benthic diatoms from Potter Cove, King George Island, Antarctica
- 2008
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In: Botanica Marina. - 0006-8055. ; 51:1, s. 51-68
-
Journal article (peer-reviewed)abstract
- Antarctic benthic marine diatoms from the Potter Cove region, King George Island were studied in samples collected during the austral summer 2003. A floristic list was made to add information on the Antarctic benthic diatom distribution. A total of 84 species was identified from four localities in Potter Cove, the majority of which are of cosmopolitan distribution. The most common taxa encountered were Cocconeis spp., Gyrosigma fasciola, Navicula cf. cancellata, N. cf. perminuta, Petroneis plagiostoma and Pleurosigma obscurum. Both G. fasciola and P. obscurum are recorded for the first time from Antarctica with such common occurrence. The overall diatom population in Potter Cove appeared rather different from other diatom populations observed in Antarctic marine habitats.
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| 9. |
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| 10. |
- Al-Handal, Adil Y, 1952, et al.
(author)
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Mastogloia jahniae sp. nov., a new diatom (Bacillariophyceae) from the Baltic Sea coast of Sweden
- 2021
-
In: Phytotaxa. - : Magnolia Press. - 1179-3155 .- 1179-3163. ; 484:1, s. 121-128
-
Journal article (peer-reviewed)abstract
- Described is here Mastogloia jahniae sp. nov. a species new to science from Skatan on the Baltic Sea, east coast of Sweden. Description of this new species is based on light and scanning electron microscopy. The new species is classified in the Mastogloia section Ellipticae and is characterized by having radiating short and long striae around the central area, sinuous raphe branches and partecta displaced toward the middle of the valve by a siliceous flange. M. jahniae sp. nov. in terms of size is rather small whereas in terms of ecology appears an epipelic brackish water species. The new species was rather rare in all samples collected from Skatan and has not been found in the other adjacent regions sampled. A comparison with similar established Mastogloia species is provided.
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