Silica-scaled Chrysophytes from Portugal

Phytoplankton samples from lakes, reservoirs and ponds in Central Portugal were obtained and the scale-bearing chrysophytes investigated by electron microscopy. This is the first study on the occurrence and distribution of these organisms in Portugal and in the Iberian Peninsula as a whole. It reports the presence of 23 species of the genera Chrysosphaerella, Paraphysomonas, Spiniferomonas, Mallomonas and Synura . Most of the species found are of worldwide distribution but a few rare organisms were present in some samples. To conclude, the perspectives of future research in Portugal are briefly outlined.     

Scale-bearing chrysophytes from tropical Northeast India

This is the first publication describing scale-bearing Chrysophyceae from India by means of electron microscopy. Twenty seven such taxa are described from samples for ponds, rivers and thermal springs. Twenty of these are Mallomonas spp.: M. akrokomos, M. bronchartiana, M. caudata, M. ceylanica, M. costata, M. crassisquanta, M. cyathellata var. cyathellata, M. cyathellata var. chilensis, M. cyathellata var. kenyana, M. guttata, M. heterospina, M. mangofera f. mangofera, M. mangofera f. foveata, M. mangoferea I. reticulata, M. matvienkoae I. matvienkoae, M. mat-vienkoae var. grandis, M. morrisonensis, M. peronoides, M. portae-ferreae , and M. tasmanica . Three are Synura taxa: S. curtispina, S. petersenii f. petersenii , and S. petersenii I. kufferathii . Two are Spiniferomonas species: S. coronacircumspina and S. enigmata. Paraphysomonas and Chrysosphaerella were each represented by one species: P. vestita and C. longispina . The water bodies from which these samples were taken were mostly eutrophic and nutrient rich. The majority of the taxa were obtained during the summer months when water temperatures were high. This contradicts the widely held belief that silica-scaled chrysophytes are mainly found in cold oligotrophic and mesotrophic waters. Mallomonas portae-ferreae and one unidentified species of Mallomonas were recorded also from thermal springs having water temperatures up to 50°C.     

Sicilica-scaled chrysophytes from Korea, a preliminary study

Phytoplankton samples obtained from 10 localities in Korea (Democratic People's Republic of Korea, DPRK) have been examined by means of electron microscopy. 27 species of silica-scaled chrysophytes (Chrysophyceae and Synurophyceae) have been identified, belonging to the genera Chrysosphaerella, Spiniferomonas, Paraphysomo-nas, Mallomonas , and Synura. Almost all of these species are new to Korea, only two of them have with certainty been found there before.     

Records of chrysophytes with siliceous scales (Mallomonadaceae and Paraphysomonadaceae) from Finnish inland waters

Seventy-three taxa of silica-scaled chrysophytes were found with LM and TEM in 264 samples from 141 Finnish water bodies, including the genera Mallomonas (40 taxa), Synura (9), Chrysosphaerella (3), Spiniferomonas (8) and Paraphysomonas (13). More than half of the taxa are recorded for the first time from Finland and five (Mallomonas actinoloma v. actinoloma, M. favosa, M. mangofera f. gracilis, M. scrobiculata and Spiniferomonas serrata) are new to Europe. Most taxa are illustrated with TEM micrographs and the taxonomy of some interesting species is discussed in detail. The seasonal occurrence of the commonest species is described.     

Silica-scaled chrysophytes from West Greenland: Disko Island and the Søndre Strømfjord region

The flora of silica-scaled chrysophytes (Chrysophyceae and Synurophyceae) is known from two previous investigations in southern Greenland, from Narssaq (61°N) and Nuuk (64°N).
In connection with a course in Arctic Biology 25.7.-20.8 1990 chrysophyte samples were obtained from altogether 53 localities, 41 from the Godhavn region in Disko Island (69°N) and 12 from S0ndre Str0mfjord (67°N). The localities were lakes, ponds and puddles, on basalt or an acid bedrock. Fixed samples were examined by EM, and altogether twenty species were identified by their silica scales. Eight of these were new to Greenland, viz. Spiniferomonas silverensis, Mallomonas acaroides, M. alpina, M. crassisquama (previous records proved to belong to M. duerrschmidliae), M. oviformis, M. paludosa, M. tonsurata , and Synura mammillosa. The composition of the flora is discussed from ecological and biogeographic viewpoints.     

Ecological characteristics of scale-bearing chrysophytes in a small eutrophic pond in The Netherlands

In a pool near Nijmegen (The Netherlands) a study was carried out regarding the ecological characteristics of scale-bearing chrysophytes (species and groups of species). The results confirm the relatively new thought, that chrysophytes are not indicating oligotrophic waters only, but the wider range of oligotrophic to eutrophic water. In this pool ammonia and nitrate appeared to be the most important chemical variables, determinatting the development of chrysophyte species. Total and ortho-phosphorus were important variables in the second place. From the physical factors, pH-value here had less influence, while conductivity and alkalinity had none at all. However, some species of Mallomonas are able to develop at higher levels of conductivity than usually assumed. In high concentrations, ammonia could be toxic. Confirming the knowledge from literature, temperature variation is an important factor for the quantitative development of species. In particular, high abundancies occur at temperatures below around 12–14°C, which explains the decrease of chrysophytes in summertime. The presence of organic matter complicates the results and must be taken into account in future studies. For biological assessment of water quality, the results underline the necessity of having knowledge of the ecological characteristics of the individual species.     

Mallomonas madagascariensis, M. lemuriocellata and M. crocodilorum (Synurophyceae), three new species from Madagascar

Hansen, P. & Kristiansen, J. 1995. Mallomonas madagascariensis, M. lemuriocellata and M. crocodilorum (Synurophyceae), three new species from Madagascar. - Nord. J. Bot. 15: 215–223. Copenhagen. ISSN 0107–055X.
Mallomonas madagascariensis, M. lemuriocellata and M. crocodilorum are described and illustrated with TEM micrographs as the first results of studies of silica-scaled chrysophytes made in Madagascar. Their taxonomical position within the genus Mallomonas (sect. Torquatae , ser. Mangoferae ) is discussed and morphological distinguishing characters are presented.     

The distribution and ecology of Spiniferomonas (Chrysophyceae) in Connecticut (USA)

Siver, P. A. 1988. The distribution and ecology of Spiniferomonas (Chrysophyceae) in Connecticut (USA). - Nord. J. Bot. 8: 205–212. Copenhagen. ISSN 0107–055X.
The genus Spiniferomonas was found to be a common member of the phytoplankton flora in Connecticut lakes, present in over thirty-seven percent of the 113 samples collected during 1984. Thirteen of the 15 known freshwater Spiniferomonas species were found including S. crucigera , recorded for the first time from North America. Six species were new records for the United States. S. trioralis, S. bilacunosa and S. bourrellyi were the most common taxa. Ecological preferences of some species are presented. This study represents the first major survey of the genus in the United States.     

Further observations on the scaled Chrysophycean and Synurophycean flora of the Ocala National Forest, Florida, U.S.A.

The distributions of silica-scaled chrysophytes in 30 freshwater ponds located in the Ocala National Forest, Florida, U.S.A., relative to chemical gradients are described. Phytoplankton, periphyton, and surface sediments from each of the 30 sites were collected in March of 2000 and later analyzed extensively with both scanning electron microscopy (SEM) and light microscopy (LM) for scaled chrysophytes. In addition, water samples were used to measure a suite of chemical characteristics, including specific conductance, pH, alkalinity, total phosphorus, total nitrogen, chlorophyll- a , chloride, sulfate and base cation concentrations. Overall, waterbodies included in this study are oligotrophic, dilute, poorly buffered and low in pH. Including six previously described species which are largely known only from the Ocala National Forest, we have identified forty-nine taxa of silica-scaled Chry-sophyceae and Synurophyceae, 23 of which were present in 5 or more waterbodies, indicating that lakes in this region are quite diverse and abundant in scaled chrysophytes. The most important species included Synura petersenii, S. echinulata and one recently reported new species from this region, Mallomonas wujekii , which was found in 73% of the lakes in this survey. The number of taxa found per lake ranged from 2 to 23 and observations include new records of several rarely reported species. Although the flora includes species commonly found in more northern regions, it also includes a group of taxa that appear to be endemic to the region and others commonly found in more tropical regions. Lastly, a new form found in ten ponds, Mallomonas transsylvanica f. curvata , is described.     

The validity of the genus Spiniferomonas (Chrysophyceae)

Cells of Spiniferomonas bourrellyi Takahashi have been shown to possess a chloroplast. A procedure for examining the same cells by both light and electron microscopy was developed so that the structure of silica scales (which is diagnostic for the species) could be confirmed for cells clearly possessing chloroplasts. A previously published proposal invalidated the genus Spiniferomonas because the type species ( S. bourrellyi ) was found to be colourless and the new genus Chromophysomonas was erected to include all remaining pigmented species of Spiniferomonas . The findings reported here support reinstatement of S. blurrily as the validated type of the genus; Chromophysomonas is considered a redundant synonym.     

Silica‐scaled chrysophytes (Chrysophyceae,Stramenopiles) of the Istrian Peninsula (Slovenia,Croatia) – species flourishing in humid subtropical climate

There are still blank areas on the map of distribution of silica‐scaled chrysophytes in Europe, the subtropical regions are especially understudied. Here, a survey of species from nine sampling sites from the Istrian Peninsula is provided. In total, only 17 mostly cosmopolitan or widely distributed species were recorded. A relatively low number of species per locality (3.7 on average) might be a consequence of low connectivity of freshwater bodies in the Istrian Peninsula, and higher levels of conductivity and pH, caused by carbonate and flysch bedrock. Species known to prefer or tolerate higher levels of those factors were especially prevalent in the investigated sites (e.g. Mallomonas heterospina and M. alata). Resistant silica scales make silica‐scaled chrysophytes a flagship group of organisms to study the biogeography of protists. Records of species from European humid subtropical climate regions have not been published to date, and the current paper may help to fill in the missing information.     

Chrysosphaerella annulata n. sp., a new scale-bearing chrysophyte

A new species, Chrysosphaerella annulata (Chrysophyceae, Paraphysomonadaceae), is described from Austria. It is also found in P. R. China, and previously reported from several places, mainly tropical, as unknown species. Its relationship to other species of Chrysosphaerella and of Spiniferomonas is discussed, and it is concluded that these two genera should be separated on silica structures rather than on unicellular or colonial habit. Accordingly, the following new combinations are proposed: Chrysosphaerella septispina and Chrysosphaerella enigmata , and the original combination Chrysosphaerella coronacircumspina has been taken up again.     

Silica-scaled chrysophytes from the bog-lake Baláta-tó, SW Hungary

Twenty-six species of silica-scaled chrysophytes representing the genera Chrysosphaerella (1 species), Mallomonas (19 species) and Synura (6 species) are reported based on transmission electron microscopy from the springtime flora of the slightly acidic bog-lake Baláta-tó, a Nature Reserve, situated in Southwest Hungary. Ten of them ( Mallomonas alata, M. clavus, M. insignis, M. mangofera, M. oviformis, M. papillosa, M. pillula, M. scalaris, M. transsylvanica and Synura multidentata ) are new records for Hungary. Furthermore, two species, M. pillula and M. scalaris are for the first time found in the Carpathian Basin and M. alata f. hualvensis is a new record for the flora of Europe. Dispersal problems are discussed.     

Silica‐scaled chrysophytes from Abisko (Swedish Lapland)

The silica‐scaled chrysophyte flora of Swedish Lapland (near Abisko) was examined. Chrysophyte scales were found in 18 of the 32 investigated water bodies (lakes and pools). Altogether, 28 taxa from the classes Chrysophyceae and Synurophyceae were found. The most abundant species was Synura echinulata. Three species were observed for the first time in Sweden: Mallomonas maculata, M. rasilis and Spiniferomonas serrata.     

Scaled chrysophytes (Chrysophyceae and Synurophyceae) from national park lakes in southern and central Finland

A total of 34 scaled chrysophyte taxa (18 Mallomonas spp., 6 Synura spp., 2 Chrysosphaerella spp., 6 Spiniferomonas spp. and 2 Paraphysomonas spp.) were recorded by SEM techniques in 61 samples from 59 lakes locating in 8 national parks of southern and central Finland in July 1987. Most of the lakes were small forest and peat bog lakes with acid (pH 4.6–7.2) and soft-water and with variable water colour (10–350 mg Pt/l). The number of taxa per lake varied from 0 to 15 and it correlated very significantly with the water pH. The species structure was rather typical for the oligotrophic and acid lakes. Besides the eurytypic and common species like Mallomonus caudata (fr. 72.1% of lakes), M. crassisquama (65.6%), M. allorgei (62.3%) and M. akrokomos (52.5%) also M. canina (41.0%) and M. hamata (21.3%) were frequently observed. M. calceolus, M. costata, M. papillosa, M. pugio and M. paludosa were more rare but typical for acid lakes. Synuru splendida which occurred in two lakes was the most rare and a new species for Finland.     

Mallomonas fuegiana (Synurophyceae), a new species of silica scaled chrysophytes from Tierra del Fuego, Argentina

Vigna, M. S. & Kristiansen, J. 1995. Mallomonas fuegiana (Synurophyceae), a new species of silica scaled chrysophytes from Tierra del Fuego, Argentina. — Nord. J. Bot. 15: 439–442. Copenhagen. ISSN 0107–055X.
During the research project "Cryptogamic Flora of Tierra del Fuego", a new species of Mallomonas has been found. It is described here as M. fuegiana , and is placed in the section Torquatae , close to Mallomonas schwemmlii and M. dickii .     

Silica-scaled chrysophytes (Synurophyceae) from some rivers and shallow lakes in Hungary

Silica-scaled chrysophytes are a special group in the phytoplankton of rivers and shallow lakes. They are present the whole year at low density, but sometimes — mainly during autumn and spring — some species can become frequent and very numerous to form real water blooms.In this study, seven species of silica-scaled chrysophytes have been recorded and identified by electron microscopy of phytoplankton samples from some rivers and shallow lakes in Hungary. Most of these silica-scaled chrysophytes have previously been found in eutrophic and hypertrophic localities, and almost all of them are common and widely distributed, even cosmopolitan. Only Synura echinulata Korshikov has not previously been recorded from Hungary. Some of them as Synura curtispina (Petersen & Hansen) Asmund, S. petersenii Korshikov, Mallomonas acaroides Perty emend. Ivanov, M. tonsurata Teiling were frequently found in the phytoplankton samples. Sometimes in autumn and winter Synura petersenii was the most abundant species in the phytoplankton and formed blooms.     

Scale-bearing Chrysophyceae (Mallomonadaceae and Paraphysomonadaceae) from Mackenzie Delta area lakes, Northwest Territories, Canada

Scale-bearing Chrysophyceae have been examined by means of light, scanning electron, and transmission electron microscopy. Samples were taken from nine arctic lakes in the Mackenzie Delta area of the Northwest Territories, Canada. Seventeen species of the genera Chrysosphaerella, Mallomonas, Paraphysomonas, Spiniferomonas and Synura have been identified. Included in these species are seven species previously unreported from northern Canada and one species reported only in North America. The composition of the chrysophycean flora from the Mackenzie Delta area lakes is compared with that of arctic lakes in the Saqvaqjuac area, Hudson Bay (N.W.T.), Alaskan lakes, and Greenland lakes.     

Freshwater scaled chrysophytes,heliozoa and thaumatomonad flagellates from Edo State,Nigeria

A total of nine silica-scaled chrysophytes (Chrysophyceae: two species each in Spiniferomonas and Paraphysomonas; Synurophyceae: five Mallomonas species), 16 heliozoa, and two scaled flagellates were recorded from 19 samples collected from Edo State, Nigeria, over a period covering both dry and rainy seasons in 2006–2007. Identifications were based on transmission electron microscopy. Eleven are new records for Africa, including a new species of Mallomonas, M. cribridomus. Also observed were two siliceous scaled colourless free-living thaumatomonad flagellates, Thaumatomastix nigeriensis and Gyromitus limax, the latter also a new record for Africa.