Search

Chaetomorpha and Rhizoclonium, two genera of the Cladophoraceae family, are rich in antioxidant, phenolic, and flavonoid compounds that have potential applications in the pharmaceutical, food, and cosmetic industries. This work examined thallus features in several populations of four Chaetomorpha species and one Rhizoclonium species. This study aimed to look into the morphological and anatomical characteristics of several populations of these taxa along the Persian Gulf and Oman Sea coasts. Good species separation in the studied species was indicated by the UPGMA dendrogram. According to a PCA-biplot of Chaetomorpha and Rhizoclonium based on equivalent morphological and anatomical parameters, the examined species can be distinguished by variables including cell wall thickness, diameter, thallus form, cell shape, and cell length. High agreement between the PCA biplot results and the heat map created using standardized morphological and anatomical features were observed. While CCA analysis of Chaetomorpha showed that the characteristic of cell wall thickness was affected by latitude, tallus form, and cell length were related to the longitude. [ABSTRACT FROM AUTHOR]

Khảo sát thành phần loài rong xanh thuộc họ Cladophoraceae ở các thủy vực nước lợ tỉnh Bạc Liêu và Cà Mau được thực hiện hàng tháng, từ tháng 05/2015 đến tháng 04/2016. Các loại hình thủy vực được chọn thu mẫu bao gồm: ao nuôi tôm quảng canh cải tiến, ao bỏ hoang, kênh/mương tự nhiên, ao nước thải. Kết quả đã xác định được 15 loài rong xanh thuộc 3 giống, trong đó Cladophora đa dạng nhất có 7 loài, Rhizoclonium có 5 loài, Chaetomorpha có 3 loài. Tần suất xuất hiện của các loài rong xanh trong ao tôm quảng canh cải tiến cao hơn so với các thủy vực khác và số loài dao động trong mỗi tháng thu từ 5-11 loài. Rong xanh xuất hiện quanh năm nhưng sự phân bố thành phần loài bị chi phối bởi sự thay đổi mùa vụ đặc biệt là độ mặn. Số loài rong xanh cao nhất được bắt gặp vào tháng 05 (11 loài) và thấp nhất vào tháng 10 (5 loài). Bên cạnh đó, rong xanh còn bị ảnh hưởng bởi sự ưu thế của các loài rong và thực vật thủy sinh khác trong thủy vực.

Cladophora fracta, a filamentous green maoroalgal epiphyte on rhodoliths, is described from five karst springs in North China. Although Cladophora species frequently appear in karst system, their genetic diversities, biogeographical affinities and physiological properties have not been well investigated in these environments. The specific objectives of this study were as follows: (1) Describe the habitat of the cladophora-like algae form the five karst springs; (2) Identify the thallus to species level based on a combination of morphological characteristics and molecular sequence; (3) Explore the morphological influence of habitat. To elucidate the biogeographical patterns in Cladophora, both morphological and molecular evidence were compared of Cladophora specimens across five study sites. Analyses of partial small subunit (SSU) and large subunit (LSU) genes revealed that the studied 50 Cladophora specimens were genetically identical species and a total of thirteen ribotypes were detected. The molecular sequencing results indicated that the examined species was highly homologous with C. vagahunda, though they shared few morphological features. The genus did not form a monophyletic clade but in three different clades both in SSU and LSU trees. The microscopic structure was more consistent with that of C. fracta. The Cladophora from the five karst springs did not show significant variation in cell dimensions. However, the species exhibited larger cell diameters than those reported from lakes. In addition, the rhizoid-like branches are only observed in two locations (XA and ST). Considering the morphological characteristics, we therefore hold our species as C. fracta. [ABSTRACT FROM AUTHOR]

Based on specimens collected in Yinggehai, Hainan, China from 2013 to 2016, a stable epiphytic taxon is found on the surface of the individual of marine green alga Cladophora aokii Yamada. According to the morphological characteristics, the taxonomy of Cl. aokii and its epiphytes is carried out. There are some epiphytes attached on Cl. aokii Yamada including Cl. fascicularis (Mertens ex C. Agardh) Kützing, Chaetomorpha pachynema (Montagne) Kützing, Ceramium camouii Dawson, Licmophora abbreviata Agardh, Lyngbya sp. and Chattonella sp.. The formation of the individual of Cl. aokii is dissected and explained, which can help to analyze the adaption in details among this species, its epiphytes and native marine environment. The results reveal the marine macroepiphytic taxonomy in Hainan, China, and preliminarily explain the adaptive relationship between macroalgae and environment. [ABSTRACT FROM AUTHOR]

Biến động sinh lượng và ảnh hưởng của rong xanh Cladophoraceae đến tôm nuôi trong các đầm quảng canh cải tiến (QCCT) được khảo sát hàng tháng từ tháng 5/2015 đến tháng 4/2016 ở tỉnh Bạc Liêu và Cà Mau. Kết quả đã tìm thấy độ phủ rong dao động từ 20% đến 90% diện tích ao, sinh lượng và sản lượng tự nhiên của rong xanh đạt khá cao, trung bình là 0,6-3,1 kg/m2, tương ứng với sản lượng tự nhiên là 1,7-16,8 tấn tươi/ha; biến động lớn trong thời gian khảo sát, trong đó sản lượng rong xanh có mối tương quan thuận với độ mặn. Ngoài ra, qua thời gian khảo sát nhận thấy sự phát triển của rong biểu thị bởi độ phủ đã ảnh hưởng đến chất lượng nước và năng suất tôm nuôi trong ao QCCT cũng như thu nhập của nông hộ. Ở độ phủ rong >50%, hàm lượng oxy hòa tan (DO) và pH biến động lớn trong ngày (DO: 3,2-6,8 mg/L và pH: 7,1-9,2). Khi rong tàn lụi, hàm lượng NO2- (4,87±1,70 mg/L) và H2S (0,03±0,02 mg/L) tăng lên rất cao và thường gây hại tôm nuôi. Năng suất tôm và thu nhập của nông hộ trong ao QCCT có độ phủ rong ≤50% (233,4±98,1 kg/ha/năm và 41,6±15,5 triệu đồng/ha/năm) cao hơn có ý nghĩa thống kê (p50% (48,1±39,9 kg/ha/năm và 13,3±6,5 triệu đồng/ha/năm). Do đó, các hộ dân nên duy trì độ phủ rong trong ao QCCT với độ phủ thích hợp khoảng 50%.

The taxonomy of the Cladophoraceae, a large family of filamentous green algae, has been problematic for a long time due to morphological simplicity, parallel evolution, phenotypic plasticity, and unknown distribution ranges. Partial large subunit ( LSU) rDNA sequences were generated for 362 isolates, and the analyses of a concatenated dataset consisting of unique LSU and small subunit ( SSU) rDNA sequences of 95 specimens greatly clarified the phylogeny of the Cladophoraceae. The phylogenetic reconstructions showed that the three currently accepted genera Chaetomorpha, Cladophora, and Rhizoclonium are polyphyletic. The backbone of the phylogeny is robust and the relationships of the main lineages were inferred with high support, only the phylogenetic position of both Chaetomorpha melagonium and Cladophora rupestris could not be inferred unambiguously. There have been at least three independent switches between branched and unbranched morphologies within the Cladophoraceae. Freshwater environments have been colonized twice independently, namely by the freshwater Cladophora species as well as by several lineages of the Rhizoclonium riparium clade. In an effort to establish monophyletic genera, the genera Acrocladus and Willeella are resurrected and two new genera are described: Pseudorhizoclonium and Lurbica. [ABSTRACT FROM AUTHOR]

Đánh giá khả năng sử dụng rong bún (Enteromorpha sp.) và rong mền (Chaladophoraceae) khô thay thế thức ăn viên cho cá tai tượng (Osphronemus goramy) được thực hiện. Thí nghiệm gồm tám nghiệm thức với ba lần lặp lại. Trong 3 nghiệm thức đối chứng (khẩu phần đơn), mỗi ngày cá được cho ăn một trong ba loại thức ăn là: thức ăn viên, rong bún hoặc rong mền. Trong năm nghiệm thức còn lại, cá được cho ăn 2 chế độ luân phiên gồm 1 ngày rong bún hoặc rong mền và 1 ngày thức ăn viên; 2 ngày rong bún hoặc rong mền và 1 ngày thức ăn viên, và kết hợp 1 ngày rong bún, 1 ngày rong mền và 1 ngày thức ăn viên. Sau 56 ngày nuôi, tỉ lệ sống của cá tai tượng không bị ảnh hưởng bởi nghiệm thức thức ăn và dao động từ 93,3 đến 100%. Tốc độ tăng trưởng của cá ở nghiệm thức cho ăn luân phiên rong bún và rong mền với thức ăn viên tương đương với nghiệm thức đối chứng. Áp dụng chế độ cho ăn kết hợp, hệ số tiêu tốn thức ăn và chi phí thức ăn viên có thể được giảm từ 43,2 đến 62,8%. Kết quả nghiên cứu cho thấy rong bún và rong mền khô có thể được sử dụng làm thức ăn thay thế một phần thức ăn viên trong nuôi cá tai tượng.

Nghiên cứu khả năng giảm thức ăn trong nuôi thẻ chân trắng (Litopeneaus vannamei) kết hợp với rong bún (Enteromorpha sp.) và rong mền (Cladophoracea) được thực hiện gồm 7 nghiệm thức với 3 lần lặp lại. Trong nghiệm thức đối chứng, tôm nuôi đơn và được cho ăn thức ăn thương mại thỏa mãn, 6 nghiệm thức còn lại tôm được nuôi kết hợp với rong bún hoặc rong mền cho ăn ở các mức 75%, 50% và 25% lượng thức ăn của nghiệm thức đối chứng. Tôm postlarvae (PL) có khối lượng trung bình là 0,036g được nuôi trong bể nhựa 100-L với mật độ 20 PL/bể (200 PL/m3) ở độ mặn 10 ppt. Rong bún hoặc rong mền được bố trí 100 g/bể đối với nghiệm thức nuôi kết hợp và rong được duy trì suốt thời gian nuôi 72 ngày. Kết quả cho thấy tỉ lệ sống của tôm không bị ảnh hưởng bởi sự giảm thức ăn. Tăng trưởng và năng suất của tôm nuôi ở nghiệm thức nuôi kết hợp cho ăn 50% hoặc 75% nhu cầu tương đương hoặc cao hơn có ý nghĩa (p2- thấp hơn nhiều so với nghiệm thức nuôi đơn (p

In spring 2014, thousands of green algal balls were washed up at Dee Why Beach, Sydney, New South Wales, Australia. Reports of algal balls are uncommon in marine systems, and mass strandings on beaches are even more rare, sparking both public and scientific interest. We identified the algal masses as Chaetomorpha linum by using light microscopy and DNA sequencing. We characterize the size and composition of the balls from Dee Why Beach and compare them to previous records of marine algal balls. We describe the environmental conditions that could explain their appearance, given the ecophysiology of C. linum. [ABSTRACT FROM AUTHOR]

The increase in global demand for fishery products has led to a fivefold increase in aquaculture production since 1990. Commercial feed is the highest production cost in intensive aquaculture, and residual commercial feed leads to eutrophication; hence it is important to find a low-cost alternative that has less environmental impact. We investigate the use of the filamentous green algae, Chaetomorpha sp., as a raw feed for giant tiger prawns. The giant tiger prawn, Penaeus monodon was grown in monoculture, and in co-culture with Chaetomorpha sp. to investigate the potential benefits of co-culturing. Five 20-day-old giant tiger prawn juveniles were released in 70-L monoculture and co-culture tanks, and the specific growth rate (SGR) and feed conversion ratio (FCR) were measured after 10 weeks. The final mean body weight of co-cultured prawns was approximately 50 % heavier than that of monocultured prawns. The SGR in co-culture tanks was 4.79 ± 0.08 % day-1 , which was higher than that in monoculture tanks (4.14 ± 0.27 % day-1 ). The FCR was 38.9 % lower in co-culture than in monoculture tanks. The protein content of Chaetomorpha sp. obtained from proximate analysis was almost the same or a little lower than other filamentous green seaweeds; however, the Chaetomorpha sp. has higher fiber and gross energy. These results show that Chaetomorpha sp. has potential for reducing feed costs in prawn intensive aquaculture through co-culturing. [ABSTRACT FROM AUTHOR]

The effects of salinity and water temperature on growth and survival of Chaetomorpha sp., one of the green tidal filamentous algae, were investigated. Field surveys revealed that this alga was abundant throughout the year in stagnant coastal waters of central Thailand. Chaetomorpha sp. was found in salinities of 3.4-90.0 and water temperatures of 20.1-40.9 °C. Chaetomorpha sp. biomass fluctuated between 9.2 and 162 kg dry weight in a saline swamp, without significant differences among seasons. The highest mean specific growth rate of approximately, 60 % day-1 was observed in laboratory experimental trials at salinities of 20-30 at 30 °C. Salinity and water temperature significantly affected growth of this alga independently and interactively. Based on these results, Chaetomorpha sp. can easily grow, survive and monopolize in stagnant waters where the salinity and temperature greatly fluctuate because of their euryhaline and eurythermal nature as well as their high growth rate. [ABSTRACT FROM AUTHOR]

Cladophora is a genus of branched filamentous green algae (Ulvophyceae). It contains many species that are challenging to differentiate based on morphology because of the scarcity of diagnostic characters and extensive phenotypic plasticity. Within the past five years, Cladophora blooms have been observed on the ropes of green-lipped mussel farms in the Marlborough Sounds, New Zealand. When Cladophora reaches high biomass, it can clog mussel-harvesting equipment; thus, it is considered a nuisance organism in the region. This study used morphological and molecular techniques to identify the species responsible for the blooms, and to investigate whether this might be a recent incursion. Cladophora samples (n = 21) were collected from nine mussel farms, one salmon farm, and a marina. Morphological and phylogenetic analyses (partial large subunit and internally transcribed spacer regions 1 and 2 of the nuclear ribosomal cistron), revealed the identity of the bloom forming species as Cladophora ruchingeri (C.Agardh) Kützing, 1845. This represents the first report of this species in the Southern Hemisphere and Pacific region. Given the distinct morphology of C. ruchingeri (when mature), its absence from previous surveys of macro-algae from this region, and increasing reports of blooms, our findings suggest that this species has only recently been introduced to New Zealand. This study provides a robust taxonomic identification and initial baseline data. Further directed studies on Cladophora are required to advance knowledge on its ecology and distribution in New Zealand, and assist in the development of mitigation strategies. [ABSTRACT FROM AUTHOR]

Pleurocladia lacustris A. Braun is a freshwater member of the Phaeophyceae, a class of algae that occurs almost entirely in marine waters. It has previously been reported from only about 13 freshwater locations worldwide, just 2 of which are in North America. Outside of North America, P. lacustris has been listed as a threatened species on several European red lists. In this paper, we report the discovery of P. lacustris in 3 calcareous streams draining the Santa Lucia Mountains in coastal California, sites that are more than 1200 km from the nearest known population. Pleurocladia lacustris is a filamentous, benthic species that forms distinctive hemispherical colonies. It co-occurs with the green alga Cladophora glomerata and species of cyanobacteria (Rivularia, Nostoc, Schizothrix spp.). Detailed color illustrations of the diagnostic macroscopic and microscopic features are provided and appear identical to those features of European populations. In the California streams, P. lacustris and other associated algae co-precipitate CaCO3 to form carbonate crusts on rocks. Preliminary ecological data are consistent with other streams and lakes in Europe where P. lacustris has also been reported (pH > 8.0, calcareous substrata, travertine). The global distribution of this presumed rare alga is also described and examined with respect to a specialized ecological niche. [ABSTRACT FROM AUTHOR]

'Green tides' are vast accumulations of unattached green macroalgae associated with eutrophicated marine environments. It had major ecological and economic impacts globally, thus understanding of their detailed conditions was required to inform management decisions. Chaetomorpha valida (Cladophoraceae, Chlorophyta), as a fouling green alga, was found in aquaculture ponds along the coast of Dalian and Rongcheng cities, People's Republic of China in the past few years. Seasonal abundances of this macroalga in China have presented a significant nuisance and caused great loss to the local aquaculture. Using unialgal cultures, the effect of temperature and irradiance on growth and reproduction were investigated. Healthy growth and reproduction occurred in the range of 17-29°C while the upper lethal limit was at 33°C. A suitable temperature range over 21-29°C and a relatively high irradiance of 108 μmol photons m s were more favorable for growth and reproduction. According to our observations, the diversity of reproductive approaches and wide adaption to temperature can be considered to be key factors that facilitate its excessive growth and colonization in spring and summer. Our results provide a basis for establishing a forecast system and taking remediation measures against seasonal green tides of this macroalga. [ABSTRACT FROM AUTHOR]

The marine green alga Chaetomorpha valida (Cladophoraceae, Cladophorales) has been found for several years fouling aquaculture ponds along coasts of the cities Dalian and Rongcheng, P.R. China. Using unialgal culture and microscopic observation, we completed the life history of C. valida and discovered fragment regeneration for the first time. The life history comprised an isomorphic alternation between gametophytes and sporophytes typical of most other members of the Cladophorales. Male and female gametes fused into zygotes then developed into sporophytes. Quadriflagellate zoospores produced by mature sprophytes gave rise to new gametophytes that yielded biflagellate gametes. Germination of zygotes and zoospores was of the bipolar erect type, as observed in some other species of Chaetomorpha. Fragment regeneration occurred in both gametophytes and sporophytes via production of polar algal fragments, which directly developed into entire filaments to give a self-replicating gene­ration. The results improved understanding of the seasonal abundances of C. valida in spring and summer. [ABSTRACT FROM AUTHOR]

The universality and species discriminatory power of the plastid rubisco large subunit (rbcL) (considering 5′ and 3′ fragments independently), elongation factor tufA, and universal amplicon (UPA), and the nuclear D2/D3 region of the large ribosomal subunit (LSU) and the internal transcribed spacer of the ribosomal cistron (ITS) were evaluated for their utility as DNA barcode markers for green macroalgae. Excepting low success for ITS, all of these markers failed for the Cladophoraceae. For the remaining taxa, the 3′ region of the rbcL (rbcL-3P) and tufA had the largest barcode gaps (difference between maximum intra- and minimum inter-specific divergence). Unfortunately, moderate amplification success (80 % excluding Cladophoracae) caused, at least in part, by the presence of introns within the rbcL-3P for some taxa reduced the utility of this marker as a universal barcode system. The tufA marker, on the other hand, had strong amplification success (95% excluding the Cladophoraceae) and no introns were uncovered. We thus recommend that tufA be adopted as the standard marker for the routine barcoding of green marine macroalgae (excluding the Cladophoraceae). During this survey we discovered cryptic species in Acrosiphonia, Monostroma, and Ulva indicating that significant taxonomic work remains for green macroalgae. [ABSTRACT FROM AUTHOR]

Abstract: The filamentous chlorophyte Chaetomorpha linum (Müller) Kützing can stand wide changes in salinity occurring in brackish and estuarine waters. In an attempt to characterize C. linum adaptation, a NaCl-induced ascorbate oxidase (AAO) activity was identified and partially characterized. Immunogold-transmission electron microscopy analysis showed AAO labelling in the cytosol, walls and chloroplasts of C. linum cells, whereas in angiosperms this enzyme is almost exclusively confined to the extracellular matrix. The possible function of AAO in adaptation and functional evolution of its cellular location is discussed. [Copyright &y& Elsevier]

A survey of the spatial distribution of benthic macroalgae in a fluvial lake of the St. Lawrence River (Lake Saint-Pierre, Quebec, Canada) revealed a shift in composition from chlorophytes to cyanobacteria along the flow path of nutrient-rich waters originating from tributaries draining farmlands. The link between this shift and changes in water quality characteristics was investigated by sampling at 10 sites along a 15 km transect. Conductivity, current, light extinction, total phosphorus (TP; >25 μg P · L−1), and ammonium (8–21 μg N · L−1) remained fairly constant along the transect in contrast to nitrate concentrations, which fell sharply. Filamentous and colonial chlorophytes [ Cladophora sp. and Hydrodictyon reticulatum (L.) Bory] dominated in the first 5 km where nitrate concentrations were >240 μg N · L−1. A mixed assemblage of chlorophytes and cyanobacteria characterized a 1 km transition zone where nitrate decreased to 40–80 μg N · L−1. In the last section of the transect, nitrate concentrations dropped below 10 μg N · L−1, and cyanobacteria (benthic filamentous mats of Lyngbya wollei Farl. ex Gomont and epiphytic colonies of Gloeotrichia) dominated the benthic community. The predominance of nitrogen-fixing, potentially toxic cyanobacteria likely resulted from excessive nutrient loads and may affect nutrient and trophic dynamics in the river. [ABSTRACT FROM AUTHOR]

Abstract  The aim of the present study was to detect organic substances functioning as osmoticants that are used by the intertidal alga, Cladophora vagabunda (L.) Hoek (Chlorophyceae), to adapt to a wide range of salinity. The major constituents of the amino acid pool were aspartate, glutamate, glycine, valine, lysine, histidine, arginine, and proline. There were concomitant increases in the acidic amino acids: aspartate and the glutamate and the basic amino acids: lysine, histidine and arginine in response to salinity stress. The appearance of proline at hypersalinity alone showed that it acts as an osmoticant. As salinity increased, there was a progressive shift in the electrophoretic pattern of protein bands. New peptide bands appeared under hyposalinity (10‰) and hypersalinity (65‰) stress conditions in addition to the usual bands which appeared in the control (35‰). Glycine betaine, which has been considered a novel organic osmolyte in a number of organisms, has also been observed in C. vagabunda in response to salinity stress. The synthesis of the compatible solute glycine betaine and the amino acid proline with increasing salinity illustrates the contention that marine algae establish an osmotic equilibrium primarily by the synthesis of organic compounds. [ABSTRACT FROM AUTHOR]

Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest that Cladophora is a likely secondary habitat for pathogenic bacteria in Lake Michigan and that the association of these bacteria with Cladophora warrants additional studies to assess the potential health impact on beach users. [ABSTRACT FROM AUTHOR]

Epiphytic and epipelic diatoms were collected from six sites in the Njoro River, Kenya, during the dry season between January and March 1997. Diatom assemblage descriptors, such as composition, distribution, species diversity as well as diatom habitat preferences and growth-form guilds were considered. Human activities in the Njoro River watershed included small-scale livestock keeping, subsistence farming, horticultural farming, and canning activities; all these activities have polluted the river. The diatom assemblages found in the Njoro River resembled those of polluted European rivers. The diatom assemblages in the Njoro River comprised eight families and 60 species. Epiphytic diatoms were obtained from the fronds of Cladophora (Cladophoraceae) and the assemblages were richer in species than the epipelic assemblages. Nitzschia amphibiaGrun. and Gomphonema parvulum (Kütz.) Grun. were found, either epiphytically and/or epipelically, in all the six sites. Percent similarity index showed that Ng’iria and Beeston sites, and Magadi and Turkana sites, were site pairs that were more similar in diatom composition. Habitat preferences were consistently demonstrated by the diatoms, distributing themselves into epipelic, epiphytic, and/or a combination of these two. The dominant diatom growth-form guild in the Njoro River was the biraphid guild, with the adnate guild being dominant in Mary Joy site, which was frequently disturbed by domestic animals and riparian human communities for water and laundry. This work fills a significant gap in that there is virtually no available data on diatoms in Kenyan streams for comparison. It further emphasizes the importance of macroflora in diversifying habitats of organisms and also in enhancing diversity in streams. Further research on diatom composition, distribution and growth-form guilds in relation to low and high hydrologic regimes is needed to address the role of environmental variability on diatom ecology. [ABSTRACT FROM AUTHOR]

The effects of salinity on growth, maturation and photosynthesis were examined in the filamentous algaRhizocloniumsp. (Cladophoraceae, Chlorophyta) growing in a brackish water habitat in a canal draining into Tokyo Bay, Japan. In this habitatRhizocloniumsp. was exposed to a wide salinity range, both daily, 5−23‰ during November 1996, and hourly, 6−24‰ during the spring tide day. From the results of culture experiments, growth and maturation ofRhizocloniumsp. occurred in the wide salinity range of 10−40‰ at 20 µmol photons m−2s−1 at 20°C, but did not occur at salinity of 0‰. Light saturation on the photosynthesis-irradiance curve at 20°C at 20‰ was reached at 100 µmol photons m−2s−1, which is characteristic for shade-adapted algae. On the photosynthesis-salinity curve at 20°C at saturated irradiance (160 µmol photons m−2s−1), the net photosynthetic rate increased with increasing salinity up to 30‰ but decreased at 40‰. On the photosynthesis-salinity curve at 20°C at 20 µmol photons m−2s−1 (at nearin situirradiance), the photosynthetic rates were almost the same in the salinity range from 0 to 40‰. Therefore, this species is able to grow, reproduce and photosynthesize with a relative efficiency in a wide salinity range, which shows that it is well adapted to a brackish water environment. [ABSTRACT FROM AUTHOR]

The chemical composition of the brackish-water green alga Cladophora rivularis was investigated. Seven sterols were identified and the stereochemistry of the most common forms was established. Thirty-eight and 21 compounds were identified in the volatile and polar fractions, respectively. The main lipid classes were isolated and their fatty acid compositions established. The antibacterial, antimycotic and cytotoxic activities of the extracts were investigated. Comparisons were made with previously investigated marine and freshwater Claclophora species. Results obtained give information on the effect of salinity on algal metabolism. [ABSTRACT FROM AUTHOR]

It is known that cellulose I[subα] is metastable and mostly converted into I[subβ] phase by a heat treatment of 280°C in an inert gas, helium. To elucidate the mechanism of this heat-induced crystal transformation from cellulose I[subα] to I[subβ], we measured X-Ray diffraction of the highly crystalline cellulose (I[subα] rich type) samples as a function of temperatures. In the heating process, d-spacings of equatorial reflections increased in line with the temperature, and furthermore the rate of change of the d-spacings increased considerably above. 200°C. This result indicated that 200°C was the critical temperature for breaking intermolecular hydrogen bonds. Above that temperature, cellulose molecular chains became more flexible, inducing a thermal expansion of the crystal lattice, and it formed a transformation intermediate, a "high-temperature" structure. In the cooling process, new types of hydrogen bonds may form at 200°C as a result of the transformation from I[subα] to I[subβ] phase. This indicates that I[subα] transformed into I[subβ] via the above expanded intermediate. The heat-induced expansion of the crystal lattice may be a trigger for the rearrangement of the hydrogen bonds, which may enhance the transformation from I[subα] to I[subβ]. [ABSTRACT FROM AUTHOR]

Focuses on several species of marine algae found at sites in the Gulf of Santa Clara, northwestern coast of Sonora, Mexico. Families represented including Gracilariaceae, Cladophoraceae, Corallinaceae, Rhodomelaceae, and Ulvaceae; When the highest and lowest diversity was found; Characteristics of sites with the low diversity; Characteristics of sites with higher diversity including stable rocky substrates, with some intertidal pools; Most common species regardless to distribution and occurrence over time including Spyridia filamentosa, Dictyota flabellata, Struveopsis robusta, Cladophora microcladioides and Enteromorpha linza; How Rosenvingea antillarum and Cladophora vagabunda represent new records for the Gulf of California.

1. The occurrence of macroalgal mats in shallow coastal waters was studied in the Gulf of Finland, Baltic Sea. 2. Altogether, 89 sites were visited and the near-shore waters of the islands were investigated, mainly by scuba diver, to about 10 m depth. In 26 places, drifting algal mats were recorded. 3. The macroalgal mats occurred in patches of up to 10 m2 in area, in a range of depths from 0.5 to 10 m, with the optimum depth being less than 5 m. The coverage of the mat varied between 10–70%, and the thickness of the mat was found to vary between 2 and 30 cm. The most frequently recorded, dominant species was Cladophora glomerata. 4. In some cases, anoxic conditions were observed as black sediment underneath the mat. This phenomenon could be a sign of very severe eutrophication of the Baltic Sea. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Examines the distribution and systematics of Chroodactylon and Kyliniella algae from streams in North America. Variation in the cell dimension within the populations and type specimens; Similarity in the morphometry of the population;Arrangement of pseudofilaments found in the algae.

Examines the Cladophora sauteri algae in Lake Shirarutoru, Hokkaido, Japan. Distribution of the alga; Abundance of the plants in summer; Investigation of the branching of the filaments and the size of the cells.

The life history of Cladophora surera sp. nov., described from the south of the province of Buenos Aires, Argentina, was found to be diplobiontic and isomorphic with haploid gametophytic (n = 24) and sporophytic (2n = 48) plants. Other freshwater species, namely C. suhri-ana K ü tz. and C. callicoma Kü tz. have also been reported to be diplobiontic and isomorphic but differing from C. surera by their ploidy Level. Plants exhibit great morphological variation, as the number of branches/mm[sup2] tends to increase with higher water velocity, thus adopting morphotypes that resemble very different species, that is, C. vagabunda (L.) Hoek, C. glomerata (L.) K ü tz., C. laetevirens (Dillw.) Kütz., C. brasiliana Martens, C. dalmatica Kü tz., C. vadorum (Aresch.) Kü tz. and C. rivularis (L.) Hoek., but clearly differing from them by other morphological parameters; apical cell diameters. The ploidy level 24/48 has riot been established for a species of Cladophora. Autogamy is the normal conjugation method and can take place even inside the gametangia before the gametes are released. Iso-gametes conjugate in a slow behavioral anisogamy, in which the contents of one migrate to the other. Tetra-flagellate zoospores result from meiosis. [ABSTRACT FROM AUTHOR]

Two new Caribbean species of Cladophora are described: Cl. jongiorum from material collected on the coaüst of Curacao and Cl. longicellulata from specimens collected on Bermuda by various authors and wrongly identified as Cl. catenifera Kuützing. [ABSTRACT FROM AUTHOR]

Unialgal cultures of Cladophora glomerata (L.) Kütz. grew with increasing vigor at temperatures between 15 and 30 C. Vegetative cells were killed upon freezing or when exposed to temperatures above 30 C. No growth occurred at 5 C and only slight growth was observed at 10 C. Effects of near lethal temperature on C. glomerata were dependent upon the duration of exposure in addition to the actual temperature attained. The response of this alga to various temperatures under culture conditions is in accord with tolerance limits established for naturally occurring populations. It seems probable that the annual periodicity of C. glomerata is regulated in large measure by seasonal variations in water temperature, greatest abundance coinciding with water temperatures between 15 and 30 C. [ABSTRACT FROM AUTHOR]

Cladophora glomerata (L.) Kütz. was the dominant attached alga in streams and along lake shores in southern Ontario. Maximum production occurred in summer and resulted from 2 short periods of intensive vegetative growth (June and September). Optimum habitat conditions consists of a firm substrate in shallow alkaline water. These conditions are provided by harbor facilities where man-made structures supplement naturally occurring rock outcrops or cobble beaches and where nutrients are available from tributaries draining agricultural and urban land areas. Periodicity appears to be related to temperature; the interval between the 2 periods of intensive growth during warm weather decreases at successively more northern locations. Frequent observation of Cladophora growing at a single stream station revealed that variations in thallus morphology and relative cell dimensions of C. glomerata are greater than has generally been recognized. These variations can be attributed to changes in environmental conditions and events in the annual life cycle of the alga. [ABSTRACT FROM AUTHOR]