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Two new species in the genus Bacillaria, B. sinensis sp. nov. and B. dongtingensis sp. nov., are described from Dongting Lake, China. Both share the linear-lanceolate valve outline and the fault sites (i.e., branching and/or fusion of transapical ribs), the latter a character of the genus. Even though B. sinensis and B. dongtingensis are found at the same specific locality (sympatric), they differ by two characters: (1) the valves of B. sinensis have asymmetrical flanges on both sides of the raphe, while the raphe flange of B. dongtingensis is only on one side of the raphe; and (2) the valves of B. sinensis lack spines on the valve margins while B. dongtingensis has spines on both margins. Bacillaria sinensis and B. dongtingensis both possess two forms of fault sites on the same valves, i.e., they have both branching of transapical ribs and fusion of transapical ribs on the broader side of valve. This feature is not found in other species of Bacillaria, so it is unique. Bacillaria sinensis and B. dongtingensis are the first two species of Bacillaria reported from a typical and ‘normal’ freshwater habitat.

Recent years have witnessed a convergence of data and methods that allow us to approximate the shape, size, and functional attributes of biological organisms. This is not only limited to traditional model species: given the ability to culture and visualize a specific organism, we can capture both its structural and functional attributes. We present a quantitative model for the colonial diatom Bacillaria paradoxa, an organism that presents a number of unique attributes in terms of form and function. To acquire a digital model of B. paradoxa, we extract a series of quantitative parameters from microscopy videos from both primary and secondary sources. These data are then analyzed using a variety of techniques, including two rival deep learning approaches. We provide an overview of neural networks for non-specialists as well as present a series of analysis on Bacillaria phenotype data. The application of deep learning networks allow for two analytical purposes. Application of the DeepLabv3 pre-trained model extracts phenotypic parameters describing the shape of cells constituting Bacillaria colonies. Application of a semantic model trained on nematode embryogenesis data (OpenDevoCell) provides a means to analyze masked images of potential intracellular features. We also advance the analysis of Bacillaria colony movement dynamics by using templating techniques and biomechanical analysis to better understand the movement of individual cells relative to an entire colony. The broader implications of these results are presented, with an eye towards future applications to both hypothesis-driven studies and theoretical advancements in understanding the dynamic morphology of Bacillaria.

Microphytobenthos (MPB) or benthic microalgae are recognized as the dominant flora in shallow neritic ecosystems such as mangroves. The diversity, biomass and community composition of microphytobenthos in selected mangrove ecosystems along the southwest coast of India were assessed. A total of 110 species of microphytobenthos classified under 49 genera were identified during the study. Nine subclasses of MPB were identified—subclass Bacillariophycidae, Fragilariophycidae, Urneidophycidae, Coscinodiscophycidae, Melosirophycidae, Thalassiosirophycidae, Biddulphiophycidae, Oscillatoriophycidae and Nostocophycidae. Division Heterokontophyta (diatoms) was the best-represented division followed by division Cyanophyta. Diatoms comprised 81% of the microphytobenthic community in the selected mangrove ecosystems, and among these, the pennate diatoms (93%) dominated the total diatom population. The major diatom genera observed during the study were Amphora, Navicula, Pleurosigma, Gyrosigma, Mastoglia, Diploneis, Cocconeis, Lyrella, Entomoneis, Caloneis, Bacillaria and Nitzschia. Episammic and epipelic diatoms were observed (Cocconeis sp., Pleurosigma sp.) along Kollam and Kannur, whereas at Kochi, epipelic diatoms were dominant (Nitzschia sp., Navicula sp.). The study also provides a spatial comparison between the microphytobenthic communities within the study area and can act as a baseline data for the trophodynamic studies of the highly diverse ecologically and economically significant mangrove ecosystems.

Bacillaria sinensis Bing Liu & D.M. Williams sp. nov. (Figs 1���29) LM: Valves linear-lanceolate, often with slightly swollen central margins (e.g. Figs 1���9), tapering to cuneate or rostrate apices (Figs 1���11). Valve dimensions (n = 40): 52���84 ��m long, 4.6���5.6 ��m wide. Fibulae distinct, situated approximately along valve midline, unevenly spaced, 7���12 in 10 ��m. Striae indistinct, parallel throughout valve, 27���29 in 10 ��m. Fault sites on valve broader side difficult to discern using LM. SEM: Colony and frustule view: Cell to cell attachment forms colony (Figs 12, 13). Frustule composed of (probably) five open girdle bands (Figs 14���17, labeled B1 to B5), four associated with the epivalve, only one is seen with the hypovalve (Figs 16, 17). Pars exterior deeper than pars interior, stepped, two rows of poroids located in pars exterior along midline, except near each apex becoming one row (Figs 15, 16, arrow, 17). Poroids of valvocopula covered externally by hymenes (Figs 15���17). Valve view: Valve linear-lanceolate, with slightly swollen central margins (Figs 18, 24). Raphe nearly central, continuous from pole to pole, distal raphe endings T-shaped (���tongue-in-groove��� structure); two raphe flanges present on each side of raphe, asymmetrical due to raphe flange on narrower valve side more developed than that on broader side, terminating before reaching poles (Figs 14���23). Transapical ribs originate with raphe ribs, parallel; striae uniseriate, composed of rounded areolae covered by hymenes externally, continuing onto mantle. Marginal spines absent. On broader side of valve, one transapical rib forming two branches at some sites (Figs 19, 21, 25, 28, 29, arrow, respectively), or two merging into one occasionally (Figs 15, curved arrow; 19, 22, 23, 29, three curved arrows, respectively). Fibulae rib-like, arching into cell (Figs 24���29). Two fibular ribs asymmetrical, i.e. fibular rib on broader side of valve more developed than that on narrower side (Fig. 26, arrows). Internally, raphe straight, continuing from pole to pole where its distal raphe fissure curves into raised helictoglossa (Figs 26, 27). Type:��� CHINA. Hunan province: West Dongting Lake, Yang���s Village, a sampling point near the lakeshore, 28�� 52��� 29.5��� N, 112�� 16��� 52��� E, 50 m asl., Bing Liu, 23 rd April 2017 (holotype BM! 81944, specimen circled on slide, illustrated as Fig. 1; isotype JIU! G202101, specimen circled on slide, illustrated as Fig. 3). Etymology:���Named after China where the species was found (the specific locality is Dongting Lake). Ecology:��� Bacillaria sinensis was commonly found in the surface sediment collected in West Dongting Lake. Associated species comprised Entomoneis triundulata Bing Liu & D.M. Williams (in Liu et al. 2018: 242), Ulnaria dongtingensis Bing Liu (in Liu et al. 2019: 127), and some species of Navicula Bory (1822: 128), Nitzschia Hassall (1845: 435), Sellaphora Mereschkowsky (1902:186), Surirella Turpin (1828: 362, 363), Tryblionella Smith (1853: 35), and others. The following environmental parameters were measured in the field. Conductivity was 109.3 �� 0.1 ��S��� cm-1, pH was 8.3 �� 0.2 and water temperature was 23.5 �� 0.3 ��C. Since the diatom sample was collected using lens tissue from the mud surface and the water conductivity is above 100 ��S��� cm-1, Bacillaria sinensis can be considered an epipelic alkaliphilous diatom characteristic of moderate electrolyte content in freshwaters., Published as part of Long, Ji-Yan, Williams, David M., Liu, Bing & Zhou, Yang-Yan, 2021, Two new freshwater species of Bacillaria (Bacillariophyta) from Dongting Lake, China, pp. 243-256 in Phytotaxa 513 (3) on pages 245-249, DOI: 10.11646/phytotaxa.513.3.4, http://zenodo.org/record/5310508, {"references":["Liu, B., Williams, D. M. & Ector, L. (2018) Entomoneis triundulata sp. nov. (Bacillariophyta), a new freshwater diatom species from Dongting Lake, China. Cryptogamie, Algologie 39: 239 - 253. https: // doi. org / 10.7872 / crya / v 39. iss 2.2018.239","Liu, B., Williams D. M., Blanco S., Liu Z. - X. & Liu, D. (2019) Three new species of Ulnaria (Kutzing) Compere (Bacillariophyta) from China, with reference to the fine structure of their valvocopula. Cryptogamie, Algologie 40: 119 - 139. https: // doi. org / 10.5252 / cryptogamie-algologie 2019 v 40 a 11.","Bory de Saint-Vincent, J. B. G. M. (1822) Bacillarees. Dictionaire Classique d'Histoire Naturelle 2: 127 - 129.","Hassall, A. H. (1845) A history of the British freshwater algae, including descriptions of the Desmideae and Diatomaceae, with upwards of one hundred plates, illustrating the various species. I. Highley, London, 462 pp. https: // doi. org / 10.5962 / bhl. title. 22609","Mereschkowsky, C. (1902) On Sellaphora, a new genus of diatoms. Annals and Magazine of Natural History, Series 7 9: 185 - 195. http: // doi. org / 10.1080 / 00222930208678565","Turpin, P. J. F. (1828) Observations sur le nouveau genre Surirella. Memoires du Museum d'Histoire Naturelle 16: 361 - 368.","Smith, W. (1853) Synopsis of British Diatomaceae. John Van Voorst, London, 89 pp."]}

Bacillaria dongtingensis Bing Liu & D.M. Williams sp. nov. (Figs 30–58) LM: Valves linear-lanceolate, tapering to cuneate or rostrate (Figs 30–40). Valve dimensions (n = 81): 53–99 μm long, 4.4–5.7 μm wide. Fibulae distinct, placed approximately along valve midline, unevenly spaced, 6–12 in 10 μm. Striae indistinct, parallel throughout valve, 24–26 in 10 μm. Fault sites on valve broader side difficult to discern using LM. SEM: Colony and frustule view: Cell to cell attachment forms colony (Fig. 41). At least two open girdle bands (Figs 43–46, labeled B1 to B2). Poroids of valvocopula covered externally by hymenes (Figs 45, 46). TABLE 1. Comparison among similar Bacillaria species. Valve view: Valve linear-lanceolate (Figs 41, 43, 47, 53). Raphe nearly central, continuous from pole to pole, distal raphe endings T-shaped (Figs 45, 46, 49, 52); one raphe flange present on narrower side of valve, irregular or complete lacking, terminating before reaching poles (Figs 42–52, RF). Transapical ribs originated with raphe ribs, parallel; striae uniseriate, composed of rounded areolae covered by hymenes externally, continuing onto mantle. Marginal spines distinct (e.g., Figs 44–46, 48, 49). On broader side of valve, transapical rib forms two branches at some sites (Figs 42, 50, 51, 52, 55, 57, arrow, respectively; 58, two arrows), sometimes two transapical ribs merge into one (Figs 42, 48, 50, 54, 55, three curved arrows, respectively). Fibulae rib-like, arching into cell (Figs 53–58). Two fibular ribs asymmetrical, i.e. fibular rib on broader side of valve more developed than that on narrower side (Figs 54, 56, FR). Internally, raphe straight, continuing from pole to pole where its distal raphe fissure curves into raised helictoglossa (Figs 55, 56). Type:— CHINA. Hunan province: West Dongting Lake, Yang’s Village, a sampling point near the lakeshore, 28°52’29.5” N, 112°16’52” E, 50 m asl., Bing Liu, 23 rd April 2017 (holotype BM! 81955, specimen circled on slide, illustrated as = Fig. 30; isotype JIU! G202102, specimen circled on slide, illustrated as Fig. 32). Etymology:—Named after Dongting Lake, where the species was found. Ecology:— Bacillaria dongtingensis was commonly found in the surface sediment collected in West Dongting Lake with B. sinensis. For details see above.

Mangrove pneumatophores (respiratory roots) form a unique habitat about which very little ecological information is available. In this study, epiphytic diatoms on the pneumatophore surface of Avicennia officinalis (L.) were investigated with a focus on their seasonal and vertical distribution. The results indicated that among the seasons, highest diatom abundance was observed in monsoon. Vertically, maximum abundance was observed on 0–5 cm of the pneumatophore during post-monsoon and pre-monsoon and then gradually decreased upwards, but during monsoon, 5–10 cm section hosted maximum abundance. There was a seasonal and vertical variation on the diatom abundance and their interactive effect. This is because diatoms probably avoid the basal section (0–5 cm) of the pneumatophore during monsoon due to excessive sediment burial caused by intense riverine flux and settlement of suspended material. Overall it was found that vertically, diatoms (>70%) are mainly concentrated on the lower 0–10 cm of the pneumatophore, probably because this section remains moist during emersion period (low tide). Among the diatoms, Melosira nummuloides and Bacillaria paradoxa exhibited dominance during the monsoon, whereas Thalassiosira spp., Navicula spp., and Nitzschia spp.were prevalent during post- and pre-monsoon. To the best of our knowledge, this is the first study describing the composition of epiphytic diatoms from the pneumatophore surface of A. officinalis. Keeping in mind that these aerial roots together greatly enhance the surface area for attachment of epiphytic diatoms, their cumulative primary production would probably surpass that of mangroves on a quantitative basis and needs future investigation.

Recent years have witnessed a convergence of data and methods that allow us to approximate the shape, size, and functional attributes of biological organisms. This is not only limited to traditional model species: given the ability to culture and visualize a specific organism, we can capture both its structural and functional attributes. We present a quantitative model for the colonial diatom Bacillaria paradoxa, an organism that presents a number of unique attributes in terms of form and function. To acquire a digital model of B. paradoxa, we extract a series of quantitative parameters from microscopy videos from both primary and secondary sources. These data are then analyzed using a variety of techniques, including two rival deep learning approaches. We provide an overview of neural networks for non-specialists as well as present a series of analysis on Bacillaria phenotype data. The application of deep learning networks allows for two analytical purposes. Application of the DeepLabv3 pre-trained model extracts phenotypic parameters describing the shape of cells constituting Bacillaria colonies. Application of a semantic model trained on nematode embryogenesis data (OpenDevoCell) provides a means to analyze masked images of potential intracellular features. We also advance the analysis of Bacillaria colony movement dynamics by using templating techniques and biomechanical analysis to better understand the movement of individual cells relative to an entire colony. The broader implications of these results are presented, with an eye towards future applications to both hypothesis-driven studies and theoretical advancements in understanding the dynamic morphology of Bacillaria.

The Bacillariaceae is a very species-rich family of raphid diatoms and includes the large and taxonomically difficult genus Nitzschia, whose species are often small-celled and finely structured and have few discrete morphological characters visible in the light microscope. The classification of Nitzschia is still mostly based on one developed in the second half of the 19th century by Grunow, who separated the genus into a series of sections largely on cell shape and symmetry, the position of the raphe, transverse extension of the fibulae, and folding of the valve. We assembled and analysed single-gene and concatenated alignments of nSSU, nLSU, rbcL, psbC and cox1 to test Grunow’s and subsequent classifications and to examine selected morphological characters for their potential to help define monophyletic groups. The maximum likelihood trees were equivocal as to monophyly of the family itself but showed good support for each of eight main clades of Bacillariaceae, three of which corresponded more or less to existing genera (Hantzschia, Cylindrotheca and Bacillaria). The other five main clades and some subclades comprised groups of Nitzschia species or assemblies of Nitzschia species with other genera (Pseudo-nitzschia, Fragilariopsis, Neodenticula, Tryblionella, Psammodictyon). Relationships between most of the eight main clades were not resolved robustly but all analyses recovered Nitzschia as non-monophyletic. The Grunowian classification of Nitzschia into sections was not supported, though in some respects (e.g. treatment of sigmoid species) it is better than subsequent reclassifications. Several of the main clades and subclades are cryptic (lacking morphological synapomorphies) and homoplasy is common in both light microscopical and ultrastructural characters (to the extent that organisms initially assigned to the same species sometimes prove to belong to a different main clade). Nevertheless, some characters, including the structure of the raphe canal and girdle, seem to be sufficiently conservative evolutionarily to give a provisional estimate of relationships if molecular data are unavailable. No new formal classifications are proposed but various options are explored and research needs identified. info:eu-repo/semantics/acceptedVersion

This research is aimed to know the diversity, composition and structure of phytoplankton community and the contamination status of organic wastes in the Sebangau river bengkiray Palangkaraya port. This research uses purposive sampling that is calculation of dominance index calculation data for phytoplankton using Simpson dominance index formula. With a total composition for all types of 756 species. The results showed that the highest composition was Bacillaria group (79%), while the other group was Chlrophyta (9%) and Cyanophytacomposition (12%). The presence of phytoplankton as an indicator that the water in the waters of the Sebangau river is not polluted, because the phytoplankton is a plant whose respiration system utilizes carbon dioxide and releases oxygen so that the water in the waters of the Sebangau River is of good quality and feasible to consumed.

The use of diatoms as bio-indicators of water quality is common in temperate regions worldwide. However, less attention has been accorded to sub-tropical regions, particularly in Australia. This study assessed the value of diatom communities to infer water quality in a sub-tropical riverine system. Epilithic diatom and water samples were collected monthly from an east Australian river. Principal components analysis showed that the Lower Catchment sites were more strongly influenced by the measured environmental variables differentiating them from the Upper Catchment sites. Canonical Correspondence Analysis showed electrical conductivity and total phosphorus strongly influenced the diatom community distribution. The study revealed diatom species that are robust bio-indicators of water quality in this sub-tropical catchment. Cocconeis placentula, C. placentula var lineata, Gomphonema spec 2 and Tabellaria flocculosa were identified as indicators of moderate water quality. Bacillaria paradoxa, Navicula cryptocephala, Navicula mutica var mutica and Achnanthes fogedii were identified as indicators of poor water quality. This study identified that diatoms are effective indicators of water quality. Further research is required to develop a diatom biological index applicable to sub-tropical east Australian river systems to improve the effectiveness of environmental monitoring and sustainable river management.

In order to assess the effects of Fe-enrichment on the growth and domoic acid (DA) production of the toxigenic diatom Pseudo-nitzschia multiseries, static cultures that received the addition of different iron (Fe) concentrations were maintained for 30 days. Intra- and extracellular DA concentrations were evaluated over time, and growth and chain-formation were compared to those of non-toxic diatoms, Bacillaria sp. Growth rates of P. multiseries (μ = 0.45–0.73 d−1) were similar among cultures containing different Fe concentrations. Likewise, the similar incidence and length of P. multiseries stepped cell chains (usually 2–4; up to 8-cell long) among the treatments reinforces that the cultures were not growth-inhibited under any condition tested, suggesting an efficient Fe acquisition mechanism. Moreover, DA concentrations were significantly higher under the highest Fe concentration, indicating that Fe is required for toxin synthesis. Bacillaria sp. reached comparable growth rates under the same Fe concentrations, except when the dissolved cell contents from a P. multiseries culture was added. The 50–70% reduction in cell density and 70–90% decrease in total chlorophyll-a content of Bacillaria sp. at early stationary growth phase indicates, for the first time, an allelopathic effect of undetermined compounds released by Pseudo-nitzschia to another diatom species.

The study aimed to identify the level of diversity of phytoplankton and zooplankton around Muara Tallo, Makassar. The study was conducted for 3 months, namely May to July 2018, in three observation stations, namely location 1 which is located around the mangrove forest, location 2 is located around the estuary of the Tallo River and location 3 which is located around Paotere Harbor, Makassar. Plankton sampling is carried out in the morning using plankton net No. 25. Plankton samples are then taken to the laboratory for identification and analysis.The results showed that when sampling at station 1 there were species of Leptocylidricus sp. Phytoplankton, and Cosvinodiscus sp. and Pleurosigma sp., Paralia sp., Bacillaria sp., but Chaetoceros sp. not found on this station. At the Station 2 phytoplankton species found were Cosvinodiscus sp. and Leptocylidricus sp., then Pleurosigma sp. and at station 3 phytoplankton can be found namely phytoplankton of Leptocylidricus sp., and Cosvinodiscus sp. While station 1 found abundance of phytoplankton, namely the type of Leptocylidricus sp. and Cosvinodiscus sp. Station 2 abundance of types of Leptocylidricus sp., Cosvinodiscus sp. Pleurosigma sp. and Paralia sp. while station 3 is the abundance of phytoplankton in Leptocylidricus sp., Cosvinodiscus sp., Bacillaria sp. and Chaetoceros sp.

Based on the field survey data of four cruises in 2011, all phytoplankton communities in the southern Yellow Sea (SYS) were investigated for the species composition, dominant species, abundance and diversity indices. A total of 379 species belonging to 9 phyla were identified, of which the most abundant group was Bacillariophyta (60.9%), followed by Pyrrophyta (23.7%) and Haptophyta (6.9%). The seasonal distribution of abundance was: summer (4137.1×103 ind m−3) > spring (3940.4×103 ind m−3) > winter (3010.6×103 ind m−3) > autumn (340.8 ×103 ind m−3), while the horizontal distribution showed a decreasing tendency from inshore to offshore regions. The dominant species of phytoplankton varied in different seasons. The dominant species were Thalassiosira pacifica, Skeletoema spp. and Chaetoceros cinctus in spring, Chaetoceros debbilis, Chaetoceros pseudocurvisetus and Chaetoceros curvisetus in summer, Thalassiosira curviseriata, Alexandrium catenella and Ceratium fusus in autumn, Paralia sulcata, Phaeocystis sp. and Bacillaria paradoxa in winter, respectively. In SYS, the group of temperate coastal species was the major ecotype, and the groups of the central SYS species and oceanic species were also important constituents. The average values of Shannon-Weaver diversity index (H’) and Pielou evenness index (J) were 2.37 and 0.65 respectively. The indices H’ and J in the open sea were higher than those in coastal waters. Obvious co-variation tendencies between H’ and J were observed in all but the summer cruise of this survey.

We proved the feasibility of using a microfluidic chip to culture diatom Bacillaria paradoxa, and analyzed the gliding characteristics of its self-organized colony in detail. The optimal cultivation parameters of B. paradoxa for the designed chip made with polydimethylsiloxane are as follows: the preferable cells injecting rate for keeping the cells alive is 0.2 mL/h, the initial cell density for fast reproduction is 5.5 × 10(4) cells/mL, and the optimal replacement period of culture medium is 4 days. B. paradoxa tends to form a colony during their growth, and the colony can glide with a steady period of 29 ± 3 s along its axial direction in a constant stream, the amplitude of the colony will not decay (e.g., 24 μm of two-cell colony at 1.1 mm/s flow rate), and the colony rapidly adjusts its direction of gliding to the direction of water flow. The successful culture of diatoms on a microfluidic platform may be used for biosensing chips and the creation of gasoline-producing diatom solar panels.

Feeding intensity and diet composition of Hilsa Shad (Tenualosa ilisha) from Northern Bay of Bengal were studied between June 2010 and March 2011. The stomach contents of 320 fishes were analyzed from the northern part of the Bay of Bengal to understand the food items of this species. The major constituents of food are organic debris (26.06 ± 5.19 % SD), diatoms (31.22 ± 11.97 % SD), other algae (12.41 ± 2.62 % SD), and crustaceans (3.50 ± 1.28 % SD). The most abundant species of diatoms were Coscinodiscus, Pleurosigma, Bacillaria, Nitzschia, Biddulphia, Diatoma and Asterionella. The stomach of Hilsa was found to be almost empty during June to October while it was almost full during November to March. Significant positive correlation among feeding intensity, chlorophyll-A concentration and salinity of the ambient water indicated that feeding in T. ilisha is influenced by a number of factors. Strong positive correlation between percentage occurrence of diatoms and intensity of feeding indicated their preference for diatom–food.

Partial synchronization of the colonial diatom Bacillaria "paradoxa"

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.

Bacillaria paxillifera – perhaps better known by its synonym B. paradoxa – is epi-typified with material from close to the type locality. Its morphology – from the living cell and intact colony to the fine structure of the valve and girdle bands – is established using light microscopy, transmission electron microscopy and scanning electron microscopy. Since B. paxillifera is also the generitype, Bacillaria is here revised and emended to include only brackish-freshwater taxa showing the unique fibulate raphe system and construction type of this genus. Three new taxa are described within the re-defined genus: B. paxillifera var. czarneckii, B. kuseliae and B. urve-millerae, differing mainly in their raphe flanges, cell-outline and shape and number of plastids. The first taxon was found in both the Mississippi River, USA, and the River Weser, Germany, the second in the Avon River, Australia, and the third at a freshwater influx into the Atlantic in The Gambia, West Africa. Historical taxa, such as Grunow's B...

Defined by its unique colonial locomotion, Bacillaria paxillifer (O. F. Mull.) Hendey was recognized as a single, pandemic species by many phycologists. However, reinvestigation of colonies from different habitats revealed three distinct groups: (A) brackish/freshwater, (B) marine littoral, and (C) marine planktonic taxa. Groups differed in colony and cell form, raphe flanges (RFs), shape and position of transapical ribs (Tr's), and morphogenesis. Linear-shaped species were restricted to group A: Tr's thickened principally to the interior. Lanceolate forms were confined to groups B and C: valve formation proceeded from an internal base layer to the exterior. The planktonic species differed in the shape of its raphe slit, and the transformation of girdle bands (GBs) into “winglets.” Taxa also differed in chloroplast shape and number. All species formed motile colonies. Siblings adhered via elastic fibrils secreted through their raphe. Raphe ribs were held in position by siliceous clamps (fibulae), anchored in an extra pair of axial ribs (fibular ribs) parallel to the raphe ribs. This raphe system resembled that of Cylindrotheca rather than the “canal raphe” of Nitzschia. Many valves were asymmetric along the apical axis due to protruding RFs shuttling in a 1:1 ratio within a colony, but raphe slits were mirror images, as were the growth direction of fibulae and position of plastids, with pyrenoids tilted in the same direction. Species possessed four open GBs per epitheca; the third band invariably bore an internal, organic ridge to aid in adhesion of the plasmalemma during cleavage. The results suggested that these taxa are a natural phylogenetic group, requiring precise determination of their taxonomic position.

Diatom assemblages attached to the leaves of the submerged macrophyte Vallisneria aethiopica in the shallow waters of the Sanyati Basin in Lake Kariba were analysed to assess their response to human impact. Human activities occurring within approximately 500 m of the shoreline were assessed at ten sampling sites along the shores of the basin. Eleven human activity factors were assessed and scored on a scale of 0 (not occurring at the site), 1 (low), 2 (medium) and 3 (high). Based on these 11 factors, we obtained a total score for the sites, which were then categorized as either having no human disturbance (0), low human disturbance (1–11), medium human disturbance (12–22) or high levels of human disturbance (23–33). Three sites were categorized as having no human disturbance, one had low disturbance and six had medium level human disturbance. A total of 9993 diatoms belonging to 40 genera were identified. The most abundant genera were Achnanthidium and Gomphonema, which made up 23.4 and 42.9% of the total diatom count, respectively. Achnanthidium dominated in remote areas with minimal human activities, while Gomphonema was more abundant in areas adjacent to increased human activities. The relative abundances of Achnanthidium, Denticula, Pinnularia, Rhopalodia and Stauroneis were negatively and significantly correlated, while that of Gomphonema was positively and significantly correlated to the human disturbance score (Spearman correlation, P 0.05), the lowest levels of these descriptors of community assemblage occurred at sites located near areas with relatively high human activities. The abundances of Achnanthes, Cymbella, Denticula, Encyonema and Pinnularia, Bacillaria and Mastogloia, Diatoma and Navicula and Eunotia and Mastogloia significantly decreased with increasing levels of total phosphorous, nitrate–nitrogen (N), ammonium–N and water turbidity, respectively (Spearman correlation, P < 0.05). Of the16 diatom index of biotic integrity (DIBI) metrics, 11 were significantly correlated with at least one of the environmental variables, while nine metrics were significantly correlated with the composite DIBI. Among the environmental variables the disturbance score was the only one that was significantly correlated with the DIBI. We conclude that although there is need for further work, periphytic diatoms associated with V. aethiopica may potentially be useful in assessing ecological conditions or the impact of human activities within the shallow marginal waters of Lake Kariba.

The selection of suitable and indigenous species is a fundamental requirement in developing oil-rich microalgae for biodiesel production. So it is necessary to evaluate the growth characteristics and lipid content of the interested microalgae species and obtain a basic knowledge about their potential towards biodiesel production. In this study, the total lipid content and biomass concentration under normal culture conditions of thirty- five diatom species (with twenty-six species being studied for the first time) belonging to nineteen genera obtained from different locations were examined. The results showed that the total lipid content is species-dependent, ranging from 4.86% to 48.61% dry weight. Twenty-four strains (64.9%) had total lipid contents higher than 20% dry weight, and nine strains (24.3%) had total lipid contents greater than 30% dry weight. Achnanthes amoena and Proschkinia sp. had total lipid contents up to 48.61% and 41.42% dry weight, respectively. Compared with the centric diatoms, most species with high lipid content were pennate. In addition, various biological characteristics were documented, including cell size and the ability to survive in various environments. The results revealed that some diatom species here such as Bacillaria paradoxa, Navicula molli, Navicula halophila and Phaeodactylum tricornutum could be regarded as potential sources for biodiesel production.

The effects of urban pollution from Hanoi city on the benthic diatom communities of the Nhue–Tolich river system were studied during the 2003 dry season. Benthic diatoms were allowed to grow on glass slides suspended in the water flow for 4 weeks. To reveal the relationship between water quality and diatom communities, Canonical correspondence analysis (CCA) was used on data concerning relative abundances of diatom species and environmental variables. Two diatom indices, IPS and DAIpo, were applied to evaluate water quality in the three rivers. A total of 291 diatom taxa were found in the Red, Nhue and Tolich Rivers. These were mainly cosmopolitan taxa, with some tropical, subtropical and endemic taxa. The most abundant taxa at the Red site were Aulacoseira granulata, Achnanthidium minutissimum, Encyonema minutum, Navicula recens and other halophilous taxa such as Nitzschia kurzii, Seminavis strigosa, Entomoneis paludosa, Bacillaria paradoxa. Diatom assemblages at the Tolich site consisted mainly of Nitzschia umbonata, Nitzschia palea and Eolimna minima. Diatom density ranged from 660 to 30,000 cells/cm2. Environmental variables and diatom assemblage composition at all sites were significantly correlated. Two diatom indices gave similar results and indicate the Tolich River with the lowest values as a highly polluted site.

Species composition and ecological preferences of the most important periphytic diatom taxa were studied in lentic ecosystems in the salt marshes of Emporda wetlands (NE Spain). Correspondence analysis with the diatom communities suggested that water confinement/flooding gradient and productivity of the system were the principal factors affecting diatom distribution in the salt marshes of Emporda wetlands. Hierarchical analysis clusters allowed 5 diatom assemblages be distinguished, each one characteristic of different degrees of confinement and productivity. Bacillaria paradoxa appeared as the most characteristic species in low confinement and high productivity conditions. Navicula perminuta and N. salinarum were representative of flooding and low productivity conditions. During maximum confinement and low productivity situations Cocconeis placentula dominated the diatom community. When maximum confinement was attained in the waterbodies with higher productivity, this dominance was shared with Nitzschia archibaldii. The 39 species considered proved to be tolerant to salinity and nutrients (nitrogen, phosphorus and organic matter) variability. This seems to be a prerequisite for survival in salt marshes where the very dynamic nature of the system results in a large variability of the physical and chemical water composition.

We observed the succession and appearence species of the marine benthic diatoms for the effective seed production of shellfish culture on wave plates in indoor mass culture tanks. Every five days, the existence species and densitiy of diatoms were counted during the 20 culture days. Experimental conditions were 8.5 0.3 of water temperature, 1.02501.0260 of specific gravity, 2,20013,000 lux of light intensity. The total density of appearence species was rapidly increased with the lapse of time. However, the number of appearence species decreased on the 20th day. The diatoms observed were 10 species; Navicula sp. of, viridula, Cylindrotheca closterium, Licmophora sp., Pleurosisma normnii, Bacillaria Paradoxa Asterionella glacialis, Stephanopuis sp. cf, turris, Entomoneis sp., Odontella aurita and Cocconeis sp, cf, scutellum. Of them, Navicula sp, of, viridula was most dominant throughout the experiment.

Diatom communities were analyzed in 39 streams located in drainages with varied land-use practices throughout Victoria, Australia. Thirteen water quality parameters were also measured in each stream. Most streams had low HCO3 1− concentrations (low buffering capacity) with >90% of the waters dominated by Na1+ and Cl1−. Phosphate concentrations ranged from 0.003 to 2.0 mg/L. Diatom communities (245 taxa) were strongly correlated with land-use practices, i.e. historic clear cutting, and secondary salinization. Streams influenced by heavy irrigation practices and dryland farming had reduced species diversity and richness compared to systems with low to moderate land use. A nonmetric multidimensional ordination of diatom communities in the 39 streams was conducted. An ANOSIM on the ordination showed that diatom communities in upland watersheds with native forest canopies and low salinization, lowland streams in watersheds with cleared forest canopies, moderate agricultural utilization and salinization, and lowland streams in areas with high irrigation and salinization were all significantly different (p

Tychoplanktonic and epilithic diatom samples were taken monthly during one year at 18 sites in small lowland rivers in the northern central region of Portugal. Canonical correspondence analysis was used to explore the relationships between measured environmental variables and patterns in the diatom assemblages. Conductivity, HCO3−, and chemical oxygen demand (COD) were the most significant environmental variables influencing the structure of the tychoplankton and of the epilithon. Other less important variables, such as K+, Fe, N(NO3−), and Na+ also explained significant (P 600 μS·cm−1), alkaline pH, HCO3− concentrations equal or higher than 150 mg·l−1, the first group includes Achnanthes hungarica Grunow, Amphora pediculus (Kutzing) Grunow, Bacillaria paxillifera (O. F. Muller) Hendey, Cymatopleura solea (Brebisson) W. Smith, Navicula accomoda Hustedt, Navicula lanceolata (Agardh) Ehrenberg, Navicula trivialis Lange-Bertalot, Nitzschia hungarica Grunow. In waters of lower conductivity (varying between 72 and 262 μS·cm−1) slightly acid pH (6 to 6.5) and HCO3−1 lower than 46 mg·l−1 the following species were common: Achnanthes oblongella Ostrup, Achnanthes subatomoides (Hustedt) Lange-Bertalot, et Archibald, Cymbella gracilis (Ehrenberg) Kutzing, Cymbella naviculiformis Auerswald, Diatoma mesodon (Ehrenberg) Kutzing, and Eunotia exigua (Brebisson) Rabenhorst. Considering COD, two further groups were distinguished. At high values (> 40 mg·l−1) the following taxa were observed: Achnanthes delicatula (Kutzing) Grunow, Navicula capitata Ehrenberg var. hungarica (Grunow) Ross, Nitzschia nana Grunow, Pinnularia interrupta W. Smith, Thalassiosira pseudonana Hasle & Heimdal, Thalassiosira weisflogii (Grunow) Fryxell et Hasle. For lower values than 19 mg·l−1, we found Cymbella naviculiformis Auerswald, Diatoma mesodon (Ehrenberg) Kutzing, Eunotia exigua (Brebisson) Rabenhorst, Fragilaria arcus (Ehrenberg) Cleve, and Nitzschia epithemioides Grumow var. disputata (Carter) Lange-Bertalot.

Many experiments utilize static immersion tests to evaluate the performance of ship hull coatings. These provide valuable data; however, they do not accurately represent the conditions both the hull and fouling organisms encounter while a ship is underway. This study investigated the effect of static and dynamic immersion on the adhesion and settlement of diatoms to one antifouling coating (BRA 640), four fouling-release coatings (Intersleek(®) 700, Intersleek(®) 900, Hempasil X3, and Dow Corning 3140) and one standard surface (Intergard(®) 240 Epoxy). Differences in community composition were observed between the static and dynamic treatments. Achnanthes longipes was present on all coatings under static immersion, but was not present under dynamic immersion. This was also found for diatoms in the genera Bacillaria and Gyrosigma. Melosira moniformis was the only diatom present under dynamic conditions, but not static conditions. Several common fouling diatom genera were present on panels regardless of treatment: Amphora, Cocconeis, Entomoneis Cylindrotheca, Licmophora, Navicula, Nitzschia, Plagiotropis, and Synedra. Biofilm adhesion, diatom abundance and diatom diversity were found to be significantly different between static and dynamic treatments; however, the difference was dependent on coating and sampling date. Several coatings (Epoxy, DC 3140 and IS 700) had significantly higher biofilm adhesion on dynamically treated panels on at least one of the four sampling dates, while all coatings had significantly higher diatom abundance on at least one sampling date. Diversity was significantly greater on static panels than dynamic panels for Epoxy, IS 700 and HX3 at least once during the sampling period. The results demonstrate how hydrodynamic stress will significantly influence the microfouling community. Dynamic immersion testing is required to fully understand how antifouling surfaces will respond to biofilm formation when subjected to the stresses experienced by a ship underway.

A study of the diversity and succession of phytoplankton in the Lagos Lagoon was carried out for two years 1988-1989. Species richness (d) and Shannon and Weaver Index (H) decreased inland while the relationship between equitability (J) and total number of individuals (N) was inverse. There was greater similarity between stations in the wet season and among stations close to one another. Coscinodiscus, Aulacoseira, Bacillaria, Odontella, Gomphosphaeria, Paralia, Desmidium, Microcystis, Hyalodiscus and Amphora were possibly the most prevalent phytoplankton genera in the lagoon at different periods.

Four new taxa belonging to the genus Attheya West are described from the west coast of Britain and from the North Sea. Attheya arenicola sp. nov. was found on sandy beaches in southwest Wales, Cornwall and the west coast of Scotland in the U.K., and on the edge of the North Sea at Renesse, Netherlands. A. flexuosa var. flexuosa sp. nov. and A. flexuosa var. enodulifer sp. nov. have been found in a similar habitat attached to cells of Hantzschia Grunow and Bacillaria Gmelin spp. A. longicorrus sp. nov. attaches to other diatoms in the plankton. Using light and electron microscopy, they are compared with A. decora West, the type species of Attheya, and with Chaetoceros sessilis Grontved, Gonioceros armatus (T. West) H. & M. Peragallo and Gonioceros septentrionalis (Ostrup) Round, Crawford & Mann. It is suggested that all taxa should be placed within Attheya because of similarity of horn structure and habitat preferences.

The motile diatom, Bacillaria paxillifer (O.F. Mull.) Hendy, shows a remarkable form of gliding motility in which entire colonies rhythmically expand and contract as single units. Cultures of Bacillaria grown under an alternating light/dark regime were found to exhibit rhythms in cell motility with the majority of colonies being motile during the light periods and non-motile and aligned during the dark periods. In continuous darkness, the majority of colonies remained non-motile and aligned, showing no rhythm in cell motility. The observed rhythms were, therefore, not endogenous but may have resulted from a photokinetic response

The nuclear gene for the small subunit (16S-like) rRNA molecule from the major genera in the family Bacillariaceae has been amplified from either purified or bulk nucleic acid preparations using polymerase chain reactions. The amplified gene has been digested with selected pairs of restriction enzymes prior to cloning into the phage Ml3 for sequencing. Recognition sites for the restriction enzyme, BamHl, are present in this gene from Cylindrotheca closterium but not in the species of Nitzschia, Bacillaria, Hantsschia and Skeletonema tested. Cylindrotheca also has one recognition site for the enzyme, HindIII, while the other genera in the Bacillariaceae have two.

Even though most natural salt marshes and saline waters became in the CR extinct, halophilous diatoms still survive in czech running waters. In 2006 two remarkable diatoms Pleurosira laevis and Bacillaria paxillifera, appeared in river stretches, where halophilous diatoms do not normally occur. Well developed populations of the first species occupied the bottom of the Bilina River. This is its first record from the CR. The second species was found in Ostravice, Odra, Labe and Jizera Rivers. For the last time this peculiar diatom was observed in the CR in 1960ies.

The worldwide effort to grow nanotechnology, rather than use lithography, focuses on diatoms, single cell eukaryotic algae with ornate silica shells, which can be replaced by oxides and ceramics, or reduced to elemental silicon, to create complex nanostructures with compositions of industrial and electronics importance. Diatoms produce an enormous variety of structures, some of which are microtubule dependent and perhaps sensitive to microgravity. The NASA Single Loop for Cell Culture (SLCC) for culturing and observing microorganisms permits inexpensive, low labor in-space experiments. We propose to send up to the International Space Station diatom cultures of the three diatom species whose genomes are currently being sequenced, plus the giant diatoms of Antarctica (up to 6 mm length for a single cell) and the unique colonial diatom, Bacillaria paradoxa . Bacillaria cells move against each other in partial synchrony, like a sliding deck of cards, by a microfluidics mechanism. Will normal diatoms have aberrant patterns, shapes or motility compared to ground controls? The generation time is typically one day, so that many generations may be examined from one flight. Rapid, directed evolution may be possible running the SLCC as a compustat. The shell shapes and patterns are preserved in hard silica, so that the progress of normal and aberrant morphogenesis may be followed by drying samples on a moving filter paper "diatom tape recorder". With a biodiversity of 100,000 distinct species, diatom nanotechnology may offer a compact and portable nanotechnology toolkit for space exploration anywhere.

Seasonal variation of conditions in Ambon Bay affected the existence of phytoplankton organisms. These organisms are the dominant pelagic primary producers that convert inorganic substances into organic compounds through the photosynthetic processes. This study aims to determine the composition, density, and distribution of phytoplankton in relation to the characteristics of the waters. Phytoplankton sampling was conducted vertically in the euphotic zone by using a plankton net KITHARA every month from June 2011 to May 2012. This study found 4 classes of phytoplankton which consist of Bacillariophyceae (38 genera), Dinophyceae (13 genera), Cyanophyceae (1 genus), and Chrysophyceae (2 genera). Genus Trichodesmium , Cyanophyceae class dominated waters in East Season, Transition Season II, West Season and Transition Season I. ANOVA test of the abundance of phytoplankton obtained significant differences in the distribution of the both temporal and spatial, the correlation of the physical and chemical characteristics of the waters with an abundance of phytoplankton showed that East Season dominated by Gonyaulax (Dinophyceae) and Bellerochea (Diatom) which is influenced by phosphate, silica, ammonia, turbidity, pH and DIN:DIP. Transition Season I and West Season dominated by Triceratium, Skeletonema, Bacillaria, Planktoniella, Ditylum, Diploneis and Prorocentrum are affected by temperature, salinity, nitrite, ration of dissolved inorganic nitrogen to dissolved silicon, secchidepth and euphotic zone.

The establishment of chloroplasts as cellular organelles in the dinoflagellate, heterokont (stramenopile), haptophyte, and cryptophyte algae is widely accepted to have been the result of secondary endosymbiotic events, that is, the uptake of a photosynthetic eukaryote by a phagotrophic eukaryote. However, the circumstances that promote such associations between two phylogenetically distinct organisms and result in the integration of their genomes to form a single functional photosynthetic cell is unclear. The dinoflagellates Peridinium foliaceum and Peridinium balticum are unusual in that each contains a membrance-bound eukaryotic heterokont endosymbiont. These symbioses have been interpreted, through data derived from ultrastructural and biochemical investigations, to represent an intermediate stage of secondary endosymbiotic chloroplast acquistion. In this study we have examined the phylogenetic origin of the P. foliaceum and P. Balticum heterokont endosymbionts through analaysis of their nuclear small subunit ribosomal RNA genes. Our analyses clearly demonstrate both endosymbionts are pennate diatoms belonging to the family Bacillariaceae. Since members of the Bacillariaceae are usually benthic, living on shallow marine sediments, the manner in which establishment of a symbiosis between a planktonic flagellated dinoflagellate and a botton-dwelling diatom is discussed. In particular, specific environmentally associated life strategy stages of the host and symbiont, coupled with diatom food preferences by the dinoflagellate, may have been vital to the formation of this association.

Apart from the considerable fluctuations in the salt concentration of Neusiedlersee resulting from its changeable water level, long-term alterations are detectable in the proportion of the individual ions. Formerly, Neusiedlersee was regarded as a soda lake, but recent research has shown that this is nowadays true only of the southern part, whereas Ca, Mg and SO4 have greatly increased in the northern section (Neuhuber 1971). A drop in the water level can bring about the drainage of large marginal areas and salt concentrations may rise rapidly. Heavy rains, on the other hand, can lead to a decrease in salinity. In locations of this nature the algae must therefore be able to endure high osmotic stresses in addition to possessing ion-specific resistance. Since algae present in brackish waters on the sea-shore are exposed to similar factors it is not in the least surprising to find algae of marine littoral origin thriving in Neusiedlersee (e.g. Bacillaria paradoxa, Gyrosigma macrum, Enteromorpha intestinalis). Many species found in the lake also exist in other saline inland waters (they will be discussed in more detail in connection with diatoms). A specific soda species is one that is also encountered in other soda waters, e.g. Surirella peisonis, which has been found in Guru Gol in Iran (Loffler 1956) and which was termed a ‘brackish water species bound to soda waters by Hustedt 1959, and Cholnoky 1968.

IN the Notes in NATURE for September 29, 1921 (vol. 108, p. 163), it is mentioned that Mr. J. W. Williams and Mr. H. Weaver have found the curious organ-pipe diatom, Bacillaria paradoxa, in canals and pools in Staffordshire and Worcestershire. It may be of further interest to note that while leading a party of field naturalists on a seaside expedition to Altona Bay, near Melbourne, some years ago (Victorian Naturalist, vol. xxxiv., June 1917, p. 16), we found this same diatom very abundantly both in the sea and up the Kororoit Creek for a good distance, where the water was only slightly brackish. On examining the finds at home I was struck with the fact that, whereas the marine form was very active in its peculiar sliding movement, the brackish form was sluggish in contrast. It would be interesting to know whether other observers have found the fresh water to act as an agent for “slowing down.” Probably the saline conditions of the water assisted the osmotic pressure which may induce the movement.

IN connexion with the interesting question raised by Mr. F. Chapman in NATURE of January 6, p. 15, as to the peculiar movements of Bacillaria paradoxa being due to osmotic pressure, I am writing to say that all the specimens observed by Mr. H. Weaver and myself that were gathered from the Staffordshire and Worcestershire Canal at Stourport and from ponds at Wilden and Hartlebury (see NATURE, vol. 108, p. 163) were very active and so continued during the period we kept them under observation (about a week in each case). The water in this canal and in these ponds is some eighty miles removed from the sea. It is quite fresh and not at all brackish.