Cocconeis Pediculus Research Articles

Study of Algal Diatoms in some water resources in Shaglawa District. Erbil, Kurdistan Region of Iraq

The current study was conducted to identify and study the spatial and seasonal variations of diatoms in some sites in Shaqlawa district in Erbil province for the period from September 2021 to August 2022 and considered the first attempt to identifiy diatoms in the this sites and also considered as an intensive study of the various species of the diatoms under different environmental conditions. Eighteen sites were selected, of which twelve are in springs, six of which are along the stream, as well as use indices to evaluate the water quality, such as Shannon Wiener indicators (H), and Jaccard similarity indices (SJ), 57 species of diatoms were identified at eighteen sites, where central diatoms were of two species while pennales diatoms reached fifty-five species. Highest numbers of species recorded in springs include site 3 and the highest number of species recorded in springs was at site 3 and the lower number was identified at site 10. Diatoma hiemale, D. moniliformis, Fragilaria construnes, F. crotonesis, Ulnaria ulna, Cocconeis pediculus, Navicula radiosa, Gyrosigma acuminatum, Nitzschia dubia, Cymbella excisa, Gomphonema olivaceum, Surirella ovalis considered more dominant than others diatoms species. According to Shannon Wiener indicators (H) a great diversity obtained in site 3 and 18. While lower diversity was observed in sites 5, 10 and 17. According to seasons the maximum diversity was recorded in October-2021 and minimum diversity was calculated in January-2022. The highest similarity rate observed between Sites 3 and 4 was 29.0% while the lowest similarity rate observed between Sites 1 and 10 was 7.9%. In general, the similarity rate between the sites that are considered to be low.

Trophic Status Assessment In Some Lotic Ecosystem In Turkey (Sakarya Basin)

Benthic diatoms constitute a very important group of organisms in terms of providing information about the water quality of the lotic ecosystems. This research was carried out in Istanbul creek, Aliaga creek, Bostancı creek and Orta creek in the Sakarya basin. The trophic states of these creeks were evaluated according to their diatomes. In the study, the epilithic diatoms were determined to consist of 42 taxa belonging to İstanbul creek, 28 to Bostancı creek, 25 to Orta creek and 20 to Aliaga creek. A total of 51 taxa were determined in the creeks. In this study, Cocconeis pediculus, Ulnaria ulna and Cymbella affinis were found to have the highest abundant at the stations. In the creeks, water temperature, dissolved oxygen and pH were determined as respectively 9.1-14.1 ℃, 8.2-9.4 mg L-1, 7.1- 7.5 and conductivity as 210.2 - 240.4 μS cm-1. Although different results were obtained according to the diatom indices criteria (IBD, SLA,IDSE,IDAP, TID, SID,CEE, WAT, TDI, SHE, TIT) the creeks were determined to be close to water quality class I -II according to the Surface Water Quality Regulation In general, according to the diatom index values, it has been determined that the creeks have good-medium quality water characteristics.

Flora of Lake Shirokoe and its environs of the Birsky district of the Republic of Bashkortostan

The article presents an analysis of the flora of Lake Shirokoe and its surroundings of the Birsky district of the Republic of Bashkortostan. It is shown that the flora is represented by 72 species of plants, of which: 8 species of trees, 1 species of shrubs, 2 species of semi-shrubs, 64 species of herbaceous plants. A total of 32 families, 64 genera and 72 species are represented. The most representative family is the Asteraceae, which includes 14 species. Of the small ones, 19 families with 1 species have been registered. Analysis of the flora of Lake Shirokoe shows that its composition is characterized by the predominance of hemicroptophytes - 25 species (34.7%) and cryptophytes - 17 species (23.6%). The least represented are therophytes (9.72%). Phanerophytes are also present in the flora (12.5%). These spectra of life forms belong to the moderately cold zone. The analysis of algae of the lake is carried out. It is represented by 14 species from two divisions (Diatomeae and Chlorophyta). The analysis of phytoplankton of the lake was carried out. It is represented by such species as: Navicula oblonga Kutz, Navicula menisculus Schum, Navicula viridula Kutz, Navicula elegans Schum, Cocconeis pediculus Ehrenberg, Nitzschia sigmoidea Nitzsch, Melosira varians C.Agardh, Pinnularia gibba Ehrenb, Surirella bifida Kütz, Asterionella formosa Hassall. An indicator species of pure water (Melosira varians C.Agardh) was found in water samples.

BIOGENIC AND ABIOGENIC COMPONENTS OF DUST STORMS

The article is devoted to the study of biogenic (pollen and diatoms) and abiogenic components in the composition of aeolian particles carried by dust storms. Studies of atmospheric dust were performed using a Carl Zeiss EVO 40 XVP scanning electron microscope equipped with an EDS (Energy-dispersive spectroscopy) “Inca Energy” microanalysis system. The studied samples were collected in the cities of Rostov-on-Don and Taganrog, as well as on the northern coast of the Taganrog Bay of the Sea of Azov (village Varenovka, Neklinovsky district) during a large-scale dust storm in September 2020, and a local storm in October 2019. Viewing of dust samples using a scanning electron microscope showed the predominance of mineral particles of pelitic and fine aleurite fractions in all samples. In the samples of Aeolian materials, it was possible to identify diatoms (Amphora ovalis, Staurosirella martyi, Hantzschia cf. amphioxys, Cocconeis pediculus, Actinocyclus octonarius var. tenellus, Navicula sp., Nitzschia sp., Anomoeoneis sp., Epithemia sp., Tryblionella sp., Pinnularia sp.), as well as pollen of ragweed, wormwood, cornflower, cereals and other representatives of the inter-seasonal grass of the steppe zone. To study the abiogenic component of the Aeolian material, the method of mapping elements was used. The microanalysis was carried out at a qualitative level, for clarity and information when constructing maps, the elements with the highest concentration (Si, Ca, Al) were selected. Oxygen distribution maps were analyzed separately. This method can be useful in cases where the samples contain fragmented valves of diatoms, whose identification by morphological features is very difficult. This method can be no less useful when identifying microplastic in soil, water, and Aeolian sediments.

Pollen and diatom evidence of sea water intrusion, east flood canal (Banjir Kanal Timur), Semarang, Indonesia

Semarang City, Indonesia is plagued by a combination of widespread flooding during the wet season and a lack of fresh (potable) water during the dry season, the latter related to saltwater intrusion. The East Flood Canal (Banjir Kanal Timur = BKT) was built to address these problems by improving runoff (drainage) and increasing groundwater recharge. This research was conducted to reconstruct the history of environmental change, including seawater intrusion, along the coast of Semarang using pollen and diatom assemblages from a 190-cm-long, 210Pb-dated sediment core extracted from the estuary at the mouth of the BKT. The age of the sediments within the core ranged over 160 years (the surface dated to 2014). The sediments could be subdivided into three zones on the basis of pollen assemblages and 2 zones on the basis of diatom assemblages. Lower zone assemblages, dominated by Sonneratia alba (mangrove), Acrostichum aureum (Pteridophyte), and Cocconeis pediculus (an epiphytic diatom), indicate that historically, the estuarine ecosystem was relatively open to the Java Sea and characterized by periods of marine and freshwater conditions. Thereafter, an upward increase in saline mangrove species of pollen and diatoms, combined with the loss of freshwater species (e.g., Avicennia and Rhizophora), indicates an increasing prevalence of marine conditions at the mouth of the BKT. Increasing salinity was associated with a landward shift in the mangrove ecosystem, a trend indicated by the progressive increase in mangrove plant diversity as statically manifested by the three pollen zones. This landward shift was associated with a “closing off” of marine flow in response to a significant (order of magnitude) increase in the estuarine sedimentation rates at about 1981. Increased sedimentation was presumably related to land-use changes that enhanced sediment delivery to the coast via the BKT. Inherent in these sediments were allochthonous fragments of Asterionella formosa, a freshwater species found in the upper sediment layers. The results of this study are consistent with the increased saltwater intrusion along the coast and a decline in groundwater quality.

Diatom diversity and water quality of a suburban stream: a case study of the Rzeszów city in SE Poland

Abstract The aim of this work was to investigate the diversity of diatom assemblages developed in the Przyrwa stream, to assess water quality based on benthic diatoms and to make an attempt at the identification of physicochemical factors having the greatest impact on the differentiation of diatom assemblages. Studies were conducted in 2011-2012 on the Przyrwa stream, a left-side tributary of the Wisłok River flowing through the city of Rzeszów and with its spring section located on the borders of the city. A total of 259 diatom taxa were identified in the Przyrwa stream during three studied seasons. At all investigated sites, the most abundant population consisted of Ulnaria ulna (Nitzsch) Compère, Cocconeis pediculus Ehrenb., Achnanthidium minutissimum (Kütz.) Czarnecki var. minutissimum, Navicula gregaria Donkin, Planothidium frequentissimum (Lange-Bert.) Lange-Bert., P. lanceolatum (Brébisson) Lange-Bert., Navicula lanceolata (C. Agardh) Ehrenb., Amphora pediculus (Kütz.) Grunow, Eolimna minima, (Grunow) Lange-Bert., Melosira varians C. Agardh and Cyclotella meneghiniana Kütz. Based on IPS (Specific Pollution Sensitivity Index) and GDI (Generic Diatom Index) indices, the ecological status of the Przyrwa stream was assessed as moderate to poor (mostly III-IV class of water quality), while the TDI (Trophic Diatom Index) index indicated a poor to bad ecological status (mainly IV-V class of water quality).

Cimil Deresi (Rize, Türkiye)’nin Epilitik Alg Çeşitliliği

The Ikizdere Valley is one of priority ecologic region within 200 areas where is under protection in the world. It is natural conservation area. In this study, epilithic algal diversity of Cimil Stream in the Cimil (Tiron) Valley where is one of the most important protection areas were investigated. The ecological structure of the stream is to determine by using indicator algae. According to sampling results obtained from four different stations after rainy and dry seasons (November 2010 and August 2011), total 113 taxa belongs to five different division were identified. Diatoms have the most species diversity in terms of other groups (74, 65%). This was followed by Cyanophyta (28, 25%), Charophyta (6, 5%), Chlorophyta (4, 4%) and Euglenophyta (1, 1%). Achnanthidium minutissimum, Cocconeis pediculus, C. placentula, Cymbella affinis, Gomphonema parvulum, G. truncatum, Encyonema minutum, Hannaea arcus, Navicula menisculus, N. salinarum ve Nitzschia palea are common and dominant diatom species in the Cimil Stream. Indicator species showed that the ecological situation of the Cimil Stream is not yet under intense pressure pollution. However, it is seen that the stream showed a change towards β-α-mesosaprobic conditions from oligosaprobic top to bottom. For the area's tourism potential is very high, it is recommended that the necessary measures take as to maintaining ecological structure in future.

DIATOMS (BACILLARIOPHYCEAE) IN RIVERS AND STREAMS AND ON CULTIVATED SOILS OF THE PODKARPACIE REGION IN THE YEARS 2007–2011

Diatoms Bacillariophyceae are a specialized, systematic group of algae, living in different types of ecosystems, and they are very good indicators of water quality. Recently, detailed studies have been carried out in the territory of the Podkarpacie Province on the diversity of diatoms in running waters. The area of study covers mostly the catchment of the biggest rivers of the province (mainly the Wislok River) and cultivated soils. Running waters in the Podkarpacie Province are characterized by a huge species richness of diatoms, 738 different taxa have been found so far. The highest number of taxa was noted in the Wislok River (400), while the Żolynianka and Rozanka streams and the Mleczka were also characterized by huge diversity (from 200 to over 350 taxa). In the majority of studied sites diatoms of alkaline (pH>7) and nutrient rich (eutrophic) waters dominated: Navicula lanceolata, N. gregaria, N. capitatoradiata, Nitzschia palea, N. dissipata ssp. dissipata, Achnanthidium minutissimum var. minutissimum, A. pyrenaicum, Amphora pediculus, Diatoma vulgaris, Rhoicosphenia abbreviata, Planothidium lanceolatum, Cocconeis pediculus and C. placentula var. lineata. About 150 taxa were indentified on cultivated soils, among which the largest populations were formed by Hantzschia amphioxys, Mayamaea atomus, Nitzschia palea, N. pusilla, Pinnularia obscura and Stauroneis thermicola.

Cocconeis pediculus EHRENBERG and C. placentula EHRENBERG var. placentula (Bacillariophyta): Typification and taxonomy.

The nominate varieties of the monoraphid diatoms Cocconeis pediculus EHRENBERG and C. placentula EHRENBERG are typified. Discrepancies from common concepts in Ehrenberg's types, habitats and descriptions were discovered which might affect our current understanding of both Cocconeis species. To ensure stabilization of names and concepts for these two taxa, epitypes from a location in Berlin close to the locus typicus are presented. Monoclonal cultures of these two taxa have been established. Morphological and morphometric data from clones as well as from populations for both taxa are presented. The taxonomy of C. pediculus and C. placentula var. placentula is discussed and evaluated in the context of historical and recent publications.

Seasonal abundance, community composition, and silica content of diatoms epiphytic on Cladophora glomerata

The establishment of dreissenid mussels in the Great Lakes has been implicated in causing a resurgence of benthic macroalgae, notably Cladophora glomerata (L.) Kützing. The seasonal proliferation and nutrient retention of epiphyton on Cladophora may be important to littoral zone processes. In this study, peak diatom epiphyte density (601 diatoms μg − 1 dry mass) co-occurred with peak Cladophora biomass. The exceptionally adhesive Cocconeis pediculus came to dominate the epiphyton to the near exclusion of all other diatoms by early summer, indicating powerful constraints on the epiphyte assemblage. There was a strong relationship between epiphytic silica content and epiphyte abundance, but the relationship was different between seasons. In the spring and fall when Cladophora was growing vigorously, silica content of the diatom epiphytes was 20.1–25.6 pmol Si diatom − 1 . In the summer, during Cladophora senescence, silica content was 6.5–10.0 pmol Si diatom − 1 and valves were visibly thinner. These observations suggest that diatom epiphytes may be limited by Si during peak Cladophora biomass. Areal estimates of silica content of Cladophora epiphyton was strongly related with Cladophora biomass: at 2 m depth, silica content increased from 22.7 mmol Si m − 2 in the spring to 490 mmol Si m − 2 during peak Cladophora biomass. Silica content can be a valuable proxy for diatom epiphyte abundance if the vitality of the Cladophora substrate is considered. Future work needs to assess the seasonality of pelagic versus benthic silica demand and the interannual variability of epiphyte silica content to assess how changes in Cladophora biomass may affect nearshore Si cycling.

The Relationship between the Physicochemical Structure and the Epilithic Algae Diversity of Aksu River (Isparta-Antalya)

On the chosen six sampling points on Aksu River, 80 taxa belong to Bacillariophyta, 40 taxa belong to Chlorophyta, 15 taxa belong to Cyanophyta, 2 taxa belong to Euglenophyta and 1 taxon belong to Rhodophyta, total 138 taxa were determined. The ephilitic algae biodiversity is parallel to the water quality on Aksu River. BOI 5 is the most effective parameter on the biodiversity of epilithic algae. Ammonium nitogen, ortophosphate, nitrate nitrogen, sulphate, and chloride fallow this. The dominant species differ according to sampling points. On the I. sampling point the dominant takson was Achnanthes lanceolata on the II. and III. sampling points the dominant takson was Nitzschia palea and A. lanceolata was not found on this sampling points. On the IV sampling point Cocconeis pediculus, V sampling point Navicula gracilis and on the VI. sampling point Diatoma vulgare were dominant species.

EPIPHYTIC DIATOMS ON CLADOPHORA RIVULARIS (LINNAEUS) HOEK (CHLOROPHYTA) AND POTAMOGETON PECTINATUS LINNAEUS (SPERMATOPHYTA) IN LAKE SIMENIT (SAMSUN—TURKEY)

The epiphytic algae of Lake Simenit were investigated from July 2000 to May 2001. In total, 66 taxa of epiphytic diatoms were identified. Of the taxa determined, 62 were found on Cladophora rivularis and 52 were found on Potamogeton pectinatus. Among the epiphytic algae, Cocconeis pediculus, C. placentula, Rhoicosphenia abbreviata, Fragilaria ulna, Amphora ovalis, Cyclotella meneghiniana and C. glomerata were abundant. The lake water was slightly alkaline and its hardness varied between hard and very hard. Of the different factors effecting the diatom composition conductivity, total hardness, dissolved oxygen, sulphate, chloride and temperature were the most important environmental variables. Species richness and diversity (Shannon-Weaver) were calculated for epiphytic diatoms found on C. rivularis and P. pectinatus. The relationships between the diatom composition and physicochemical variables were analysed by means Canonical Correspondence Analysis.

Distribution and Significance of Epipsammic Algae in the Coastal Shore (Ibeno Beach) of Qua Iboe River Estuary, Nigeria

The distribution of epipsammic phytoplankton in the coastal shore (Ibeno beach) of Qua Iboe River estuary was studied in the early summer (between October and December) of 1998. The results revealed the presence of Actinoptychus undulatus, Aphanizomenon flos-aquae, Astasia fustis, Chromulina globosa, Cocconeis pediculus, Cymatopleura solea, Cymbella lanceolata, Euglena intermedia, Lyngbya majusculata, Microcystis sp., Nodularia spumigena, Navicular rhynocephala, Oscillatoria nigroviridis, Pinnularia viridis, Rhoicosphenia curvata, Trachelomonas volvocina and Urceolus cyclostomus in the sandy beach. The mean species density of the epipsammic algae encountered in the beach ranged from 16 to 7600 organisms per hectare. The density, however, decreased with increase in sampling distance from the low tide level. Actinoptychus undulatus was the most abundant and widely distributed phytoplankton while Aphanizomenon flos-aquae was the least encountered species. The occurrence of A. flos-aquae and other toxin producing cyanobacterial species of Lyngbya majusculata, Microcystis sp., N.spumigena and O. nigroviridis in the sandy beach are of serious health significance.

ASSESSMENT OF WATER QUALITY USING EPIPHYTIC DIATOM ASSEMBLAGES ON CLADOPHORA FROM THE ST. LAWRENCE RIVER (CANADA)

Diatoms epiphytic on Cladophora were examined from 36 sites in the Saint Lawrence River between Salaberry-de-Valleyfield and Ile d'Orleans (Quábec, Canada). A total of 129 diatom taxa were identified from Cladophora in June 1995, and of these, 34 species were present at a relative abundance ≥ 1% at three or more sites. The four most abundant taxa were Cocconeis pediculus, Achnanthes minutissima, Rhoicosphenia abbreviata and Gomphonema minutum. Canonical correspondence analysis (CCA) was used to explore the relationship between diatom assemblages on Cladophora and measured environmental variables. Conductivity, turbidity, temperature, distance downstream from Cornwall (Ontario), and fecal coliform concentrations were significantly (p>0.05) related to the distribution of the diatoms; the primary response was to conductivity. Although this relationship was not strong (λ1=0.13 and λ2=0.08), the calibration set model generated to infer conductivity had moderate predictive ability (r2 jack=0.24 and RMSEjack=51.7). Based on modelling statistics and general observations, epiphytic diatoms on Cladophora may prove to be a useful biomonitor of water quality in the river.

EFFECTS OF WATER VELOCITY ON THE ARCHITECTURE AND EPIPHYTES OF CLADOPHORA GLOMERATA (CHLOROPHYTA)1

ABSTRACT The architecture of the filamentous green alga Cladophora glomerata (L.) Kütz. and the composition of this alga's epiphytes [primarily the diatoms Epithemia turgida (Ehrenb.) Kütz., Epithemia sorex Kütz., and Cocconeis pediculus Ehrenb.] were examined in different velocity regimes. After transferring algal‐bearing cobbles among velocities, the effects of changes in velocity were also examined. Cladophora branching pattern did not initially differ among slow, medium, and fast velocities, indicating that stable water velocities did not affect branching pattern. Two weeks after cobble transfer, Cladophora in fast velocity had fragmented more (i.e. had fewer filaments and fewer branch points per length of filament and had a higher percentage of unbranched filaments) than Cladophora in slow velocity. Fragmentation was greatest in tufts moved from slow velocity, suggesting velocity‐associated differences in susceptibility to breakage. Epiphytic assemblage composition differed among slow, medium, and fast velocities and between locations on the filament (base and apex). Cocconeis pediculus dominated where exposure to high velocity was greater (filament apices in medium and fast velocities), whereas the Epithemia spp. dominated where lower velocities occurred (filament bases in all velocities and apices in slow velocity). Two weeks after the cobble transfer, the translocated diatom assemblages had changed and the original pattern of diatom distribution was restored.

Epiphytic Diatoms on Cladophora glomerata in the Colorado River, Arizona: Longitudinal and Vertical Distribution in a Regulated River

Flagstaff, AZ 86011 ABSTRACT-Seventy-eight taxa of diatoms were identified from the epiphytic community of Cla- dophoraglomerata in the Colorado River through Glen and Grand Canyons. Achnanthes affinis, Cocconeis pediculus, Diatoma vulgare, and Rhoicosphenia curvata made up 80% of the diatom epiphyton community within 15 km of Glen Canyon Dam, Arizona. However, these taxa made up only 33% of the periphyton community 354 km downstream. Mean total diatom density associated with Cladophora glomerata was significantly reduced at each sequential station downstream. Diatom density decreased and community composition of diatoms changed with increasing water depth in the river channel. Cell densities of D. vulgare, C. pediculus, and R. curvata decreased markedly at Lees Ferry following a 3-month period of fluctuating flow during October through December 1985. Several studies on the algal communities in the Colorado River through Glen and Grand Can- yons, Arizona, were conducted prior to the com- pletion of Glen Canyon Dam near Page, Arizona, in 1963. Flowers (1959) observed 52 taxa of al- gae, including 29 taxa of diatoms in Glen Canyon, and Woodbury et al. (1959) were the first to report Cladophora glomerata (L.) Kiitz., now the dominant filamentous alga in the mainstream of the Canyon system (pers. obser.). Williams and Scott (1962) and Weber (1966, pre-dam data) listed the dominant species of diatoms at a water quality surveillance station near Page, Arizona. A few algal surveys have been conducted in the Colorado River since the completion of Glen Can- yon Dam in 1963. Crayton and Sommerfeld (1978) examined the planktonic algal species in the main river and concluded that many of the planktonic species were attached forms that had been dislodged by the current. S. W. Carothers and C. O. Minckley (in litt.) listed total numbers of epilithic diatom species for several major trib- utaries to the Canyon system. Czarnecki et al. (1976) studied the periphyton in the seeps and at the mouths of tributaries in the Grand Canyon and reported that C. glomerata was the dominant, attached green alga in the Canyon system, es- pecially at the mouths of major tributaries. Czar- necki and Blinn (1978) reported a total of 235 taxa of diatoms from the Grand Canyon system. Their study showed that Diatoma vulgare, Coc- coneis placentula, and Rhoicosphenia curvata were the dominant taxa of diatoms. Peterson (1987)

Seasonal Physical, Chemical and Algal Changes in Five Rivers Flowing Through the Oil Sands Region of Alberta, Canada

AbstractSeasonal studies concentrating upon physical and chemical parameters and the epilithic algal community were conducted at specific sites in five tributary rivers flowing through the oil sands region of northeastern Alberta, Canada into the Athabasca River. Numerically cyanophycean algae (Lyngbya aerugineo‐caerulea, Phormidium sp., Calothrix braunii, Nostoc spp. and Anabaena affinis) dominated followed by diatoms (Achnanthes lanceolata, Cocconeis pediculus, Cocconeis placentula, Epithemia sorex, Epithemia turgida, Gomphonema acuminatum, Gomphonema longiceps v. subclavata, Gomphonema olivaceum, Nitzschia fonticola, Nitzschia palea, Synedra rumpens, and Synedra ulna). One exception was the Hangingstone River where chlorophycean algae (Stigeoclonium pachydermum and Cladophora glomerata) were next in importance to the cyanophytes. Seasonal fluctuations in algal species and numbers were influenced by a myriad of interacting parameters. Physically disruptive forces (current velocity and discharge) appeared more important than dissolved nutrients. They were also responsible for affecting the chemical composition of the water itself.

Composition and abundance of phytoplankton in tributaries of the lower Colorado river, Grand Canyon region

Phytoplankton distribution and abundance in eleven tributaries of the Colorado River within the Grand Canyon were investigated from April, 1975 to June, 1976. During this period a total of 56 genera and 156 species of phytoplankton was identified. Phytoplankton species of the individual tributaries were quite distinct, with only four diatom species, Diatoma vulgare, Navicula tripunctata, Nitzschia linearis and Synedra ulna, common to all the tributaries. Bright Angel Creek, Shinumo Creek and Elves Chasm were the tributaries with the most diverse algal flora, whereas Vaseys Paradise, Tapeats Creek, Deer Creek and Havasu Creek showed the lowest species richness. Elves Chasm and Diamond Creek had the highest phytoplankton numbers. Phytoplankton abundance and species richness appeared to be influenced by high turbidity, current velocity, fluctuating water levels and age of the water. Some of the dominant algal species, Biddulphia laevis, Cocconeis pediculus, Cymbella ventricosa, Epithemia sorex, Gomphonema parvulum and Synedra ulna, showed significant correlations with specific physico-chemical characteristics of the tributaries.

Notes And Correspondence

ABSTRACT As many of your metropolitan readers may be glad to know of localities in which microscopical objects may easily be found, I beg leave to state for their information that the waters of the New River, the ornamental water in St. James’s Park, and the fountains in Trafalgar Square, will prove well worthy of investigation. During the last two months I have obtained from the New River, near the City Road, Cocconeis clypeus, Cocconeis pediculus, Fragillaria pectinalis, Synedra valens and lunaris, Closterium Leiblinii, Odontidium mesodon, Navicula Hippocampus and amphirynchus, Hydatina senta, Surirella striatula, an arborescent Vorticella with 38 animalcules, Tardigrada, Gomphonema truneatum, and a Vibrio, the species of which, from unfortunately losing the specimen, 1 could not determine.