Studies on scale–bearing Chrysophyceae from the Giessen area, Federal Republic of Germany

The Chrysophycean flora of various freshwater bodies round Giessen was studied by transmission and scanning electron microscopy between 1979 and 1982. Investigations throughout the year revealed a clear preference of most of the taxa for autumn and spring. Altogether, 32 taxa of Chrysophyceae were found. Twelve of these had previously been recorded from W Germany, only four species, however, documented by electron microscopy. Mallomonas costata sp. nov. and M. pillula f. latimarginalis f. nov. are described.     

Preliminary investigations on the distribution of scaled chrysophytes in Vermont and New Hampshire (USA) lakes and their utility to infer lake water chemistry

A total of 38 taxa of scaled chrysophytes, representing seven genera, were observed in the surface sediments of eleven lakes in Vermont and New Hampshire, USA. The number of taxa found per lake ranged from 10 to 23, with greater diversity and abundances of scales in the New Hampshire localities. The flora was similar to those described from other temperate regions of North America and Europe. The flora described from the New Hampshire waterbodies was typical of those observed in slightly acidic, dilute lakes situated in primarily forested watersheds. The flora observed in the Vermont lakes was more typical of ones previously described from regions rich in waterbodies with both high pH and concentrations of dissolved salts. The occurrences of several rarely reported species in North America, including Mallomonas alata, M. parvulu, M. retrorsu. and Synura lapponica , are documented. It was also determined that paleolimnological inference models developed in Connecticut for pH, specific conductivity and trophic score worked well using the scale remains from the study lakes.     

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.     

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.     

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.     

Silica-scaled chrysophytes of the šumava National Park and the Tfeboñsko UNESCO Biosphere Reserve (Southern Bohemia, Czech Republic)

Thirty-five taxa of silica-scaled Synurophyceae and Chrysophyceae have been identified by means of transmission electron microscopy (TEM) from eight localities in the šumava National Park and the Trebon UNESCO Biosphere Reserve. Mallomonas alveolata, M. areolata, M. costata. M. doignonii var. doignonii. M. intermedia var. intermedia. M. punctifera, M. teilingii, M. transsylvanica. Synura leptorrhabda and Paraphysomonas takahashii are new records for the Czech Republic. Autecology and distribution of selected species are discussed.     

Three new species of Mallomonas (Chrysophyceae, Mallomonadaceae) from Lake Lanalhue, Chile

Three new species of the genus Mallomonas are described. Mallomonas rasilis sp. nov. belongs to the sect. Mallomonas , ser. Papillosae , while M. scalaris sp. nov. and M. lanalhuensis sp. nov. are members of the sect. Torquatae. They were found in Lake Lanalhue, Arauco Province, Chile. The taxonomy and distribution of these species is discussed, along with the morphology of cells, scales and bristles, based on scanning and transmission electron microscopy.     

Scale–bearing Chrysophyceae (Mallomonadaceae) from Central and Northern Canada

In this study, scale–bearing Chrysophyceae (Mallomonadaceae) have been examined by means of transmission and scanning electron microscopy. Lakes in four areas in central and northern Canada, viz. Experimental Lakes Area (ELA), in northwestern Ontario, Whiteshell Provincial Park and Southern Indian Lake in eastern and northern Manitoba, respectively, and Saqvaqjuac on the west coast of Hudson Bay in the Northwest Territories have been investigated. Forty–three species of the genera Mallomonas, Paraphysomonas, Spiniferomonas and Synura have been identified in addition to three species of the genus Chrysochromulina (Prymnesiophyceae). Ten species are new to Canada; five of these have not previously been recorded from North America. Paraphysomonas elegantissima sp. nov. is described. The composition of the Canadian chrysophycean flora is compared with the chrysophycean flora of North America as a whole.     

Growth characteristics of two bloom‐forming synurophytes (Mallomonas elongata and Synura petersenii) at different nitrate and phosphate concentrations

Two dominant planktonic bloom‐forming algal species in a small shallow eutrophic pond were identified as Mallomonas elongata and Synura petersenii by electron microscopy. Their growth requirements were investigated as uni‐algal cultures in a laboratory study. The maximum population growth and maximum growth rate of M. elongata occurred at concentrations of 24 μM nitrate (NO₃) and 5 μM phosphate (PO₄) at a temperature of 15°C and a pH of 6. Synura petersenii grew maximally and exhibited the highest growth rate at a NO₃ concentration of 24 μM and a PO₄ concentration of 2 μM. Mallomonas elongata and S. petersenii had similar nutrient requirements for optimum growth, suggesting that the biomass of these two species can be controlled by nutrient gradients.     

Observations on Some Chrysomonads from Scotland

SYNOPSIS. The taxonomy of the genera Mallomonas, Mallomonopsis and Synura is based on their silica scales. Examination of water samples from Southern Scotland in the electron microscope revealed that they were plentiful in the area and permitted detailed observations on new species. Comparative studies are made on the flagella of three known species of Synura ; the "flimmergeissel" of these biflagellates appear to be more or less similar, but the whip-lash flagella show specific differences suggesting a possible secondary taxonomic criterion. The distribution of the three genera is discussed with particular reference to species found in Iceland, Scotland and Japan. A stage in the conjugation of a species of Mallomonas is described.     

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.     

Fossil diatoms and scales of Chrysophyceae in the recent history of Hall Lake, Washington

SUMMARY. Scales of several members of the Chrysophyceae (family Synuraceae) were examined from a core of the recent sediments of Hall Lake, Washington, in conjunction with a study of fossil diatoms. Both types of microfossils revealed communities changing with the historical development of the lake. Increases in planktonic diatoms and in two species of Mallomonas occurred about the time of European settlement. Several acidophilous species among the Chrysophyta disappeared with the establishment of a sawmill and meromictic conditions in the lake. When extensive road construction around the lake ended the period of meromixis, the ratio of Synuraceae, in general, to diatoms, declined. Besides the change in ratio of Synuraceae to diatoms there was a change in the composition of the community of Synuraceae at that time. Species of Synura that had been rare before became the most abundant, and Mallomonas became relatively rare. Throughout the recent history of the lake the dominant Synuraceae seemed to respond more strongly to disturbance around the lake than the most abundant diatoms; thus, scales of Mallomonas, Synura , and other Synuraceae are valuable microfossils for paleolimnological studies.     

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.     

Studies on generaMallomonas andSynura,and other plankton in freshwater with the electron microscope VIII. On three new species of chrysophyceae

Three new species (Chrysophyceae) which belong to the Torquata group of the genusMallomonas, to the Spinosa group of the genusSynura, and to the genusOhromonas were found from freshwater in the North-East of Japan by the aid of an electron microscope. They were namedMallomonas recticostata, Synura mammillosa, andOchromonas diademifera, respectively. The characteristics of the three new species are described here.     

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.     

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.     

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.     

Scale-bearing Chrysophyceae (Mallomonadaceae and Paraphysomonadaceae) from West Greenland

Phytoplankton samples from twenty-one freshwater localities in the area of Nuuk (Godthåb), West Greenland, have been examined by means of electron microscopy in order to investigate the flora of scale bearing Chrysophyceae. Forty-two taxa of the genera Mallomonas, Synura, Chromophysomonas (Spiniferomonas), Chrysosphaerella and Paraphysomonas have been observed, and thirty-eight of these are illustrated by TEM or SEM micrographs. Thirty-four of the observed taxa, among these all members of the genus Chromophysomonas , are for the first time recorded from Greenland. Chromophysomonas involuta sp.nov. is described. The scale morphology of the Greenlandic specimens is compared with earlier findings from other parts of the world, and the most remarkable features of the chrysophycean flora from the investigated area are discussed.