Number Of Diatoms Research Articles

The Diatom Attachment Scar Ophthalmichnus lyolithon igen. et isp. n.

A number of benthic diatoms (including species of the genera Cocconeis, Achnanthes, and Amphora) etch shallow attachment scars in carbonate hard substrates. The morphology of these microbioerosion traces mirrors the elliptical to biconvex outline of the diatoms, which, in its most common appearance, is expressed as a distinct ring-shaped groove. The traces are established as new ichnogenus and -species Ophthalmichnus lyolithon. The diatoms are assumed to form the etching scars by means of their adhesive mucilage composed of acidic polysaccharides, probably in order to enhance adhesion.

Species composition and distribution of microalgae in the Sukhodol River estuary (Ussury Bay, Peter the Great Bay) in autumn. 2. Epiphyton

Epiphyte microalgae from common macrophytes ( Zostera marina, Z. japonica, Ruppia maritima, Ulva prolifera, Gracilaria verrucosa, Cladophora glomerata, Phragmites australis ) were sampled in the Sukhodol estuary in September of 2012. In total, 46 taxa of diatoms are registered, 72 % of them belong to microphytobenthos. The most numerous are mesohaline species and species indifferent to salinity (in sum 71 %). Similarity between species composition of phytoplankton and epiphyton was 57.4 %, by Czekanowski-Sørensen index. Total number of the epiphyton diatoms varied from 12.9 · 10 3 to 2583.9 · 10 3 cells/g wet weight of basiphyte (on average 541.1 · 10 3 ± 111.9 · 10 3 cells/g), their biomass varied from 17.4 to 3099.0 mg/g (on average 595.0 ± 134.7 mg/g). The lowest epiphyton biomass was registered for U. prolifera (33.9 ± 11.7 mg/g) and the highest - for Z. marina (2790.6 ± 166.8 mg/g). Species composition of epiphyton is significantly different between three groups of macrophytes: 1 - seagrass of external estuary ( Z. marina ); 2 - seagrasses ( Z. japonica, R. maritima ), attached bottom macroalgae ( U. prolifera, C. glomerata, G. verrucosa ) and emergent vegetation ( Ph. australis ) of internal estuary; and 3 - drifting macroalgae ( C. glomerata ) of internal estuary. Thus, species structure of epiphyte communities changes between biotopes and between water layers in each biotope that is determined by salinity preferences of the most common epiphytes, on the one hand, and vertical distribution of macrophytes within the water column, on the other hand. Domination of such α -mesosaprobionts as Tabularia tabulata , Melosira lineata and M. moniliformis var. subglobosa indicates eutrophication of the Sukhodol estuary that presumably is maintained by terrigenous biogenic elements supply. The biogenic elements recycled and accumulated in bottom sediments are dispersed in the estuarine waters by tidal and wind-driven turbulence.

Species composition and distribution of microalgae in the Sukhodol River estuary (Ussury Bay, Peter the Great Bay) in autumn. 1. Phytoplankton

Species composition and quantitative distribution of phytoplankton in the Sukhodol River estuary were studied in September of 2012. It total, 48 species of diatoms are registered, mostly belonged to microphytobenthos (63 %). The most numerous are mesohaline species and species indifferent to salinity (in sum 69 %). The number of diatoms varied from 5.4 ˑ 10 3 to 866.2 ˑ 10 3 cells/l (on average 138.4 ˑ 10 3 ± 75.9 ˑ 10 3 cells/l), their biomass varied from 5.0 to 816.8 mg/m 3 (on average 199.5 ± 71.0 mg/m 3 : 467.8 mg/m 3 in the external estuary, 285.4 ± 117.5 mg/m 3 in the deep-water part of the internal estuary, and 42.0 ± 16.5 mg/m 3 on the shallows of the internal estuary). Species composition of phytoplankton is determined by water structure: Dactyliosolen fragilissimus (74 % of biomass) , Skeletonema costatum (15 %) and Coscinodiscus oculus iridis (8 %) are the most abundant in the external estuary where brackish water spreads in the upper layer and salt water occupies the bottom layer; Ulnaria ulna (72 %), Melosira varians (12 %) and Ctenophora pulchella (4 %) are the most abundant in the deep-water part of the internal estuary with almost fresh water in the upper layer and brackish water at the bottom; and Achnanthes lanceolata (22 %), S. costatum (21 %), Rhopalodia musculus (14 %), Pinnularia gibba (6 %), and C. pulchella (5 %) dominate on the shallows of internal estuary with only one water layer occupied by fresh water. Domination of D. fragilissimus and S. costatum indicates a high level of eutrophication in the Sukhodol estuary that presumably is caused by terrigenous biogenic elements supply. The biogenic elements recycled and accumulated in the bottom sediments are dispersed in the estuarine waters by tidal and wind-driven turbulence.

Diatoms of the lower Vistula River phytoseston

Abstract This paper presents the results of research on the phytoseston of the Vistula River along a distance of 163 km. The research was conducted between 1994 and 2010. A total of 218 diatom taxa were identified in the phytoseston. A large number of diatoms were represented by only a few specimens, and, in some cases, only in one of the 312 samples examined. Only nine species had the highest constancy of occurrence in the lower Vistula River; however, mostly periphyton and benthos species predominated the phytoseston in the Vistula River at all of the stations. Most of the species were cosmopolitan. The eutrophic conditions of the Vistula River were confirmed by the great number of eutraphentic diatom taxa. The 86 diatom species identified that have high or very high oxygen requirements confirm that oxygen conditions in the river are good. The ecological potential of the Vistula River was rated based on concentrations of chlorophyll a. The worst state, which was moderate, was recorded in 1998 at positions above the dam in Włocławek. Research on the river segment in Torun in the 2007-2010 period indicated the ecological potential had improved from good to maximum. Despite high anthropogenic pressure and major engineering projects, the Vistula River is characterized by good and maximum ecological potential and great biodiversity.

Evaluación de la calidad del agua fluvial con diatomeas (Bacillariophyceae), una experiencia en Tacna, Perú

In order to evaluate the quality of the water of the Locumba river, Tacna (Peru), water samples were taken from ten stations located along the Locumba river basin, during six periods in an annual cycle. The diversity and number of diatoms was also evaluated, together with eleven physiochemical parameters in order to determine the degree of water contamination. We found that as the basin advanced down the mountain, the diversity of diatoms decreased from 2.37 bits cell-1 to 0.71 bits cell-1 and the gradient of contaminants increased. In addition to this increase, the number of species tolerant to high levels of environmental disturbance rose. An increase in all physiochemical parameters used to evaluate the degree of contamination was observed. These results suggest that diatoms can be adequate bioindicators when evaluating the quality of water in this basin.

Diversity and Species Composition of Subaerial Algal Communities in Forested Areas of Meghalaya, India

The study deals with a comparative study on diversity and species composition of subaerial algal communities from tree barks of closed undisturbed sacred grove, mixed plantation, and open disturbed forest. A total of 85 taxa had been recorded, 30 cyanobacteria and 55 algal species belonging to six classes of algae. Sacred grove harboured the highest subaerial algal diversity compared to those of plantation and open disturbed forest. There was a strong significant difference in species composition among the three different sampling areas. High number of diatoms with 14 species was recorded in sacred grove. Cyanobacteria with 22 species were the frequent group in disturbed forest whereas Trentepohliales dominated in plantation. Canonical correspondence analysis confirmed that high photon irradiance favored the growth of cyanobacteria in disturbed forest. The abundance of Trentepohliales members correlated to high rainfall and photon irradiance. High diversity and presence of many diatom species in undisturbed Mawphlang sacred grove were associated with low photon irradiance and high relative humidity and could also be due to a presence of suitable substrata formed by the growth of mosses. Sunlight, relative humidity, and rainfall were the important factors which played a major role in determining the diversity and distribution of subaerial algal communities.

New and rare diatom (Bacillariophyta) species from a mountain lake in Eastern Siberia

The examination of a moss sample collected from a lake in a remote mountainous region of Eastern Siberia revealed a diverse diatom flora that included four new species: Eunotia frigida, Brachysira subtile, Encyonopsis vasilievae, and Neidium rugosum. N. rugosum has been previously illustrated from several locations in the arctic and subarctic and is widely distributed across the circumpolar Arctic. The distribution of three other species is likely more limited. Besides these species, a number of rare diatoms were also found in the moss community. These include Neidium boyeri and Stauroneis crassula previously known only from North America; Encyonema sibericum so far only reported from Western Siberia, Encyonema lunatum var. borealis earlier found in Finland, and Eunotia ferefalcata, Pinnularia angustarea, and Naviculadicta mongolica so far reported only from Mongolia. This study contributes to the understanding of biogeographic patterns of diatom distribution.

A testimony of detachment of an inland lake from marine influence during the mid-Holocene in the Vestfold Hills region, East Antarctica

Abstract A 47 cm long sediment core collected from an inland lake of the Vestfold Hills, East Antarctica has been examined to reconstruct the palaeolacustrine environmental changes. The core shows dates at two core intervals of 18-19 cm and 28-29 cm as 5050±98 yrs BP and 5560±96 yrs BP, respectively. The core exhibits a good amount of diatom population throughout the length. Prior to 5560±96 yrs BP, the core shows high abundance of diatom population (>10×107 g-1) along with sufficient salt crystal, which indicates the connection of this lake with the marine environment. From 5560±96 yrs BP to 5050±98 yrs BP the total number diatoms decreased substantially along with the decrease in salt crystal, which indicates the withdrawal of the marine influence from the lake during that period. From 5050±98 yrs BP to Recent, the low number of diatoms and the rare occurrence of salt crystal suggest that the lake remained mostly detached from the sea during the last 5000 yrs.

A simple DNA coprecipitation method for the detection of diatoms in heart blood

We developed a method for detecting and enumerating diatoms in the heart blood of drowning victims and evaluate its utility for diagnosing death by drowning. For purification of diatoms from blood, the DNA binding ability of the diatom frustule in the presence of a chaotropic agent was utilized. The procedure is basically the same as the commonly used method for DNA purification from blood using Proteinase K treatment and denaturation by a chaotropic agent. DNA adsorbed to the diatom (DNA/diatom complex) is recovered by ethanol precipitation, and the DNA is subsequently digested using DNase. Purified diatoms could be clearly observed under a microscope. Diatoms spiked in the blood of non-drowned cadavers (n=15) were well recovered, and were detected in heart blood from all drowning victims (n=22). The mean number of diatoms found in 5ml of blood from drowning victims was 7.8±5.8 (mean±SD), and the number of diatoms detected in the blood of the left ventricle (6.1±5.8) was approximately two times higher than that of the right ventricle (3.0±2.7, p<0.05). These results suggest that this simple and safe method can become an effective tool for diagnosing the cause of death as drowning.

Holocene environmental changes during transition Ancylus-Litorina stages in the Gdansk Basin, south-eastern Baltic Sea

Two sediment cores have been obtained from the southern and eastern parts of the Gdansk Basin for lithological, geochemical and diatom analysis. The data revealed provides information about environmental changes during the transition of the Ancylus Lake to the Litorina Sea stages. The Ancylus Lake transgression and regression phases have been well traced in the diatom flora of the shallower, eastern slope of the Gdansk Depression, whereas mentioned water level changes have not been detected in the deepwater (southern) part of the basin. The Litorina Sea has been clearly defined according to geochemical, lithological and diatom analysis. The Initial Litorina Sea transition was observed as gradually increasing numbers of brackish water diatoms and higher contents of C org and N in the sediments, when saline water influx reached the basin before 7600±184 cal. yr BP.

Association between physical and geochemical characteristics of thermal springs and algal diversity in Limpopo Province, South Africa

Algal species commonly occur in thermophilic environments and appear to have very wide geographical distributions. Presence of algal species is strongly influenced by temperature, pH and mineral content of thermal waters. No research has previously been documented on the algal diversity in South African thermal springs. This paper describes the algal distribution in 6 thermal springs in Limpopo Province, South Africa, and attempts to link this to the physical and geochemical properties of the springs. Water samples were collected from Mphephu, Siloam, Tshipise, Sagole, Eiland and Soutini thermal springs and algae identified. Temperature, pH and TDS were measured on site and water samples analysed for macro- and trace-elements. Cyanophyta was the algal group most often present, followed by Bacillariophyta, Chlorophyta, Euglenophyta and Dinophyta. Some of the algae were present in waters with pH ranging from 7.1–9.7 and temperatures ranging from 40–67°C. Others (the cyanobacteria and green algae: Nodularia, Schizothrix, Anacystis, Coelastrum, Chlorella and Spirogyra) only occurred in high temperature (60+°C) and pH>9 waters, while a number of diatoms (Synedra, Aulacoseira, Nitzschia, Cyclotella, Gyrosigma, Craticula) occurred exclusively at temperatures <45°C and pH values <8. Algae were also present in waters with fluoride values exceeding that which is considered safe for human consumption as well as in waters relatively rich in uranium, rubidium, vanadium and manganese. It was clear that the occurrence of algae coincided with specific geological formations. These algae could act as indicator species of geology and heavy metals. Keywords : thermal springs, Limpopo Province, algae, diversity, geochemical

The presence of diatom algae in a tracheal wash from a German Wirehaired Pointer with aspiration pneumonia

A 7-year-old spayed female German Wirehaired Pointer was presented with difficulty breathing after being found seizing in a water-filled drainage ditch while out hunting. Aspirates from a tracheal wash contained numerous degenerate neutrophils, fewer macrophages, some of which contained basophilic debris, low numbers of extracellular diatoms, and a single intracellular short bacterial rod. As the dog continued to clinically decline and could not be weaned from oxygen support, the owners chose euthanasia. The major necropsy finding was a severe granulomatous bronchopneumonia that was likely due to aspiration of foreign material based on the microscopic presence of plant-like material, bi-refringent crystalline material, non-cellular debris, and occasional fungal structures. Diatoms are a class of algae that live primarily in water. Diatom analysis has been used, with some controversy, in human forensics to assist in documenting drowning as the cause of death. In this case, given the clinical history, the presence of diatoms and inflammation in the tracheal wash were interpreted as a likely result of the aspiration of surface water. To our knowledge, this is the first reported case of diatoms observed in a cytologic specimen in a nonhuman mammal with aspiration pneumonia.

Evaluación de la calidad del agua fluvial con diatomeas (Bacillariophyceae), una experiencia en Tacna, Perú

In order to evaluate the quality of the water of the Locumba river, Tacna (Peru), water samples were taken from ten stations located along the Locumba river basin, during six periods in an annual cycle. The diversity and number of diatoms was also evaluated, together with eleven physiochemical parameters in order to determine the degree of water contamination. We found that as the basin advanced down the mountain, the diversity of diatoms decreased from 2.37 bits cell-1 to 0.71 bits cell-1 and the gradient of contaminants increased. In addition to this increase, the number of species tolerant to high levels of environmental disturbance rose. An increase in all physiochemical parameters used to evaluate the degree of contamination was observed. These results suggest that diatoms can be adequate bioindicators when evaluating the quality of water in this basin.

Role of Diatoms in the World of Forensic Science

This article reviews the forensic aspects of Diatoms analysis and acid digestion method for diatoms extraction. A body recovered from the water does not necessarily imply that death was due to drowning. If the person is still alive when entering the water, diatoms will enter the lungs if the person inhales water and drowns. The diatoms are then carried to distant parts of the body such as the brain, kidneys, lungs and bone marrow by circulation. If the person is dead when entering the water, then there is no circulation and the transport of diatom cells to various organs is prevented because of a lack of circulation and diatoms cannot enter the body. When a body is recovered from water, there is usually a suspicion whether it was a case of ante-mortem or post-mortem drowning i.e. whether the body was drowned before or after death. In these medico legal cases, presence of diatoms in the body tissues is very useful evidence. In drowning related death cases, a correlation between the diatoms extracted from bone marrow and liver/lungs) samples and the samples obtained from drowning medium have to be established for the successful determination of drowning site in Forensic laboratories. Diatom analysis should be considered positive when number of diatoms is above a minimal established limit; 20 diatoms/ 100 μl of pellet obtained from 10 gm of lung samples and 50 diatoms from other organs and further matching of diatoms from bone marrow and drowning site can strengthen this supportive evidence and a positive conclusion can be drawn whether person was living or not when drowned. Detection of diatoms in the bone marrow is a proof that the individual was alive when entered the water.

HOW MANY SPECIES OF ALGAE ARE THERE?

Algae have been estimated to include anything from 30,000 to more than 1 million species. An attempt is made here to arrive at a more accurate estimate using species numbers in phyla and classes included in the on-line taxonomic database AlgaeBase (http://www.algaebase.org). Despite uncertainties regarding what organisms should be included as algae and what a species is in the context of the various algal phyla and classes, a conservative approach results in an estimate of 72,500 algal species, names for 44,000 of which have probably been published, and 33,248 names have been processed by AlgaeBase to date (June 2012). Some published estimates of diatom numbers are of over 200,000 species, which would result in four to five diatom species for every other algal species. Concern is expressed at the decline and potential extinction of taxonomists worldwide capable of improving and completing the necessary systematic studies.

Effect of repeated partial cropping on population dynamics and yield of Oreochromis niloticus (L.) during polyculture with Heterobranchus longifilis (Val.)

The effect of repeated cropping of half the number of young and large adults on productivity and dynamics of Oreochromis niloticus was investigated during polyculture with Heterobranchus longifilis. Mixed-sex, large-sized and young adult tilapia of 841±0.3 g and 841±0.23 g were cultured with 40 catfish fingerlings in triplicate 36 m2 earthen ponds in 1 and 2 treatments respectively. At the 4th, 6th, 12th, 26th and 32nd week, cropping was done in treatment 2 and the weights of the crop were used to enrich supplementary feed, by displacing an equal weight of ingredients in treatment 1. Realized supplementary feed crude protein level was 12.9 and 18.3±5% in treatments 1 and 2 respectively. Feeding was at 1% body weight thrice daily. Weight data were analyzed with ANOVA and t-test. Surplus production of O. niloticus from treatment 2, calculated as sum of periodic harvest + final harvest minus final harvest in treatment 1, was 249±25 g per week. Treatment 2 had significantly higher H. longifilis harvest mean weight and growth rate (percentage per day) (p<0.01), with densities (p<0.05). It also has higher numbers of zooplankton and phytoplankton species, cyanophyceae and diatoms, as well as O. niloticus size susceptible to catfish predation. Chlorophyceae dominated the phytoplankton in both treatments. The implication of tilapia surplus production for catfish-tilapia polyculture is thus discussed. Key words: Oreochromis niloticus, partial harvest, population dynamics, compensatory growth, standing crop, surplus production, food availability, earthen pond.

Analysis of historical trend of carotenoid concentrations in sediment cores from Lake Shinji, Japan

The historical trend of the concentrations of carotenoids originating from phytoplankton in sediment cores collected at two sites in Lake Shinji, a eutrophic oligohaline lake was investigated to clarify the changes in phytoplankton community structures in the lake over the last 100 years. Eight kinds of carotenoids were detected in the sediments, i.e., astaxanthin and lutein from chlorophytes, alloxanthin from cryptophytes, canthaxanthin, echinenone and zeaxanthin from cyanobacteria, diatoxanthin from diatoms, and β-carotene from unspecified algal groups. On the basis of the stoichiometric relation between total organic carbon (TOC) and total sulfur (TS), the historical changes in the TOC concentration of sediment cores since circa 1970 have been attributable to the decomposition of organic matter by sulfate reduction, confirming the importance of diagenetic processes in Lake Shinji sediments. It was found that labile chlorophyll a is transformed diagenetically to more stable pheophytin a and pyropheophytin a within the upper 5 cm of the cores. Similarly, the concentrations (µg g ‐1 TOC) of carotenoids, other than diatoxanthin, in the cores decreased rapidly within this zone, and in the cores lower than 5 cm below lake floor, their concentrations showed a decreasing or fixed trend with depth. This suggests that these carotenoids have been degraded in sediments depending on their stabilities. Among the diatoxanthin, lutein and zeaxanthin of which the stability is similar, the relative abundance of lutein (chlorophytes) has increased since circa 1970, and, conversely, the relative abundance of diatoxanthin (diatoms) has decreased. Diatoms are likely a staple food for the shellfish Corbicula japonica in Lake Shinji, because they are rich in lipids, which are needed for the growth and survival of C. japonica. Hence, the relative decrease in the number of diatoms may have some effect on the decrease in the population of C. japonica since the 1970s in the lake.

Periphytic diatom communities in the littoral zone of the urban lake Jeziorak Mały (Masurian lake district, Poland).

This study on plant periphyton (epilython, epiphyton, and periphyton communities on artificial substratum – separator pipes) was carried out in the littoral zone of lake Jeziorak Maly in 2002 and 2003. In addition to floristic analysis, changes in the abundance and biomass of periphytic diatoms with respect to physio-chemical water parameters in the season between April and October were analyzed. The highest number of periphytic diatoms was found in the pipes in June, and the highest biomass of epilython was established in September, in conditions of high contents of Ca and Si biogenes. Moreover, the indicator potential of diatoms was used to determine the trophy and saproby of the lakes waters. The largest participation of eutraphents in the biomass in all the diatom communities generally indicates the eutrophic character of the lakes waters, the dominance of meso-saprobes and amoderate content of organic matter. Moreover, alarge proportion of alpha-mesosaprobes (dominant Navicula gregaria) in the biomass of periphytic diatoms in the pipes indicates the highest degree of contamination by organic matter there in comparison to other substrates, while the epilython had the highest biomass of beta-alpha-meso-saprobes (dominant Diatoma vulgaris), an average degree of contamination with adominance of beta-meso-saprobes (subdominant Cocconeis placentula) and the least degree of contamination by organic matter.

Numbers, Sizes, and Types of Diatoms Around Estuaries for a Diatom Test

We collected 68 fresh, brackish, and seawater samples from various sites around the estuaries of 2 rivers at high and low tides. Seawater flowed approximately 2.4 (salinity, 2.2% at the site) and 1.2 km (1.8%) upstream of the estuaries, but the surface comprised essentially fresh water up to the mouth. Sites contained 69 to 22,200 diatoms/50 mL of water, and the numbers varied by depth and at sites separated by only approximately 1.2 km. Diatoms ranged from 2.8 to 429 μm (mean range, 16.1-59.2 μm) in size. Large pennate diatoms populated fresh water areas, and most sedimented before reaching the sea. Numbers of pennate diatoms of less than 20 μm were decreased in areas of seawater. Numbers of centric diatoms tended to increase nearer the sea, and seawater contained large centric diatoms. Brackish water containing large volumes of seawater was easily discriminated by assemblages of marine diatoms, unlike that containing a little seawater, because marine diatoms could be found in fresh water around estuaries. Tides and the nature of the river often altered diatomaceous assemblages at the same estuarial sites. Caution is recommended for forensic interpretation of aqueous media to deduce drowning sites.

The development of marine biofilms on two commercial non-biocidal coatings: a comparison between silicone and fluoropolymer technologies

The antimicrobial performance of two fouling-release coating systems, Intersleek 700® (IS700; silicone technology), Intersleek 900® (IS900; fluoropolymer technology) and a tie coat (TC, control surface) was investigated in a short term (10 days) field experiment conducted at a depth of ca 0.5 m in the Marina Bandar Rawdha (Muscat, Oman). Microfouling on coated glass slides was analyzed using epifluorescence microscopy and adenosine-5′-triphosphate (ATP) luminometry. All the coatings developed biofilms composed of heterotrophic bacteria, cyanobacteria, seven species of diatoms (2 species of Navicula, Cylindrotheca sp., Nitzschia sp., Amphora sp., Diploneis sp., and Bacillaria sp.) and algal spores (Ulva sp.). IS900 had significantly thinner biofilms with fewer diatom species, no algal spores and the least number of bacteria in comparison with IS700 and the TC. The ATP readings did not correspond to the numbers of bacteria and diatoms in the biofilms. The density of diatoms was negatively correlated with the density of the bacteria in biofilms on the IS900 coating, and, conversely, diatom density was positively correlated in biofilms on the TC. The higher antifouling efficacy of IS900 over IS700 may lead to lower roughness and thus lower fuel consumption for those vessels that utilise the IS900 fouling-release coating.