Freshwater Red Tide Research Articles

Direct Payment Subsidies for Environmentally-Friendly Agriculture on Rice Production in Shiga, Japan

Environmentally-friendly agriculture has been promoted for over two decades as a response to environmental degradation and biological loss. Lake Biwa, which is a major water source in Kinki region, has suffered eutrophication resulting in occurrences of freshwater red tide and blue-green algae bloom. As a result, Shiga Prefectural government has implemented a direct payment subsidy system which would promote the environmentally-friendly agricultural (EFA) practices in order to reduce pollution load and improve the quality of Lake Biwa eco-system. This study aims to determine profit efficiency among EFA rice farmers in Shiga Prefecture using the Stochastic Frontier Approach. A cross-sectional survey was conducted among 82 farmers from top rice-producing cities in Shiga Prefecture, using a structured questionnaire. Results showed that EFA farmers increased their net farm income by 99 %, amounting to 652,414 JPY/ha compared to the 658,553 JPY/ha income of conventional farmers. However, production costs were also found to be higher among EFA farmers, especially on labor costs, which accounted for 42 % of the total production cost. The study investigated the farmer and farm-specific factors affecting deviations from the profit frontier and discussed the policy implications for the promotion and popularization of EFA in the future.

Blooms of the woloszynskioid dinoflagellate Tovellia diexiensis sp. nov. (Dinophyceae) in Baishihai Lake at the eastern edge of Tibetan Plateau

Freshwater red tides due to dinoflagellates have caused spectacular and regular summer reddening in recent years in Baishihai Lake, a temperate, meromictic, meso- or oligotrophic, high-altitude, landslide-dammed, deep lake located at the eastern edge of Tibetan Plateau in China. Based on morphological and molecular analyses, the causative organism has been identified as a new woloszynskioid dinoflagellate, Tovellia diexiensis Q. Zhang et G.X. Liu sp. nov. The vegetative cells are 20-32 mu m long and 16-24 mu m wide. They have a hemispherical episome and a broadly rounded hyposome with a short characteristic antapical spine. Usually cells are bright red due to the presence of numerous red-pigmented bodies, which often masked the yellowish green discoid chloroplasts. The amphiesma of motile cells comprise mainly quadrilateral, pentagonal or hexagonal thin plates, arranged in 4-5 latitudinal series on the episome, 1 in the cingulum and 4 on, the hyposome. Molecular phylogenies based on small subunit ribosomal DNA and large subunit ribosomal DNA (LSU) indicate T diexiensis from Baishihai Lake to belong to the family Tovelliaceae, which was monophyletic in our LSU phylogenies. During the bloom-forming period in 2005, cell density of T diexiensis reached 9.15 x 10(5) cells L-1. Astaxanthin and its diester were found to be the major pigments in T diexiensis, resulting in a characteristic blood-red color of the water in Baishihai Lake.

Preservation potential of seasonal laminated deposits as a useful tool for environmental analysis in mesotrophic Lake Kizaki, central Japan

In this paper discusses the aquatic environment at Lake Kizaki, central Japan, during the last ca. 60years and describes the importance of laminated sediments in environmental analyses. The flux of total algal carbon increased between 1965 and 1996 while the BSi flux, which can be used in diatom production, showed a larger increase between 1960 and 1998 than typically occurs on average. The flux of dinosterol, an indicator of dinoflagellate production, also increased from 1966 to 1998, and the sedimentary dinoflagellate record correlated with observations of freshwater red tides caused by dinoflagellate blooms. Parallel laminated sediment was determined to have appeared between 1960 and 1995, corresponding to a period of high total algal carbon levels and BSi fluxes. For lamina formation and its preservation process, the thickness of the oxygen-poor layer depended on excessive total algal production during stagnant periods and appeared to be important because nutrients were diffused and accumulated in the oxygen-poor layer from bottom sediments. This could result in diatom blooms at the next overturn period. The development of the thick oxygen-poor layer appeared to be triggered primarily by the presence of excessive nutrients generated by human activities. In general, the occurrence of laminated sediments can provide a useful tool for understanding the eutrophic state in Lake Kizaki.

Numerical Analysis of Flow Characteristics and Freshwater Red tide in a Reservoir Equipped with Flow Control Device

Numerical Analysis of Flow Characteristics and Freshwater Red tide in a Reservoir Equipped with Flow Control Device

Removal of Freshwater Red Tide Plankton Peridinium bipes by Coagulation and Foam Separation

Removal of Freshwater Red Tide Plankton Peridinium bipes by Coagulation and Foam Separation

Water pollution due to a harmful algal bloom: a preliminary study from two drinking water reservoirs in Kandy, Sri Lanka

A dysenteric epidemic condition occurred in a community of people who consumed water from the two reservoirs, Rosmith and Dunumadalawa in Kandy on 29th and 30th of September 2008. The symptoms were diarrhoea, vomiting and headache. It was suspected that the epidemic could relate to the water supply from the two reservoirs. To investigate the sources that caused the disease, water samples were analysed for potentially harmful biological organisms. A dinoflagellate species, Peridinium aciculiferum , known to produce a biological toxin under special environmental conditions, was identified for the first time in Sri Lanka from the samples. The relative abundance of P. aciculiferum ranged from ~75% to 100% of the plankton samples taken from all sites. The abundance and diversity of other organisms at the same trophic level were low and the eutrophication conditions were also predominant in both reservoirs at the time of sampling. It is therefore suggested that P. aciculiferum had outcompeted the other planktons in the reservoirs and the epidemic condition had arisen due to the algal toxins present in the reservoirs during the drought period. Keywords: Algal toxins, freshwater dinoflagellates, freshwater red tide, Peridinium aciculiferum , water pollution. Doi: 10.4038/jnsfsr.v39i1.2930 J.Natn.Sci.Foundation Sri Lanka 2011 39 (1):91-94

THE EFFECTS OF PHYSICAL TREATMENT ON FRESHWATER RED TIDE FORMING DINOFLAGELLLATE (PERIDINIUM): EXPERIMENTAL STUDY

We carried out experimental study investigating the effects of physical treatment on dinoflagellate (Peridinium bipes) in order to develop measure to prevent freshwater red tide in reservoirs. Surface water in the reservoir occurring freshwater red tide was sampled for the physical treatments. We found that physical treatment caused cessation of swimming of P. bipes and subsequently effects on water quality and plankton composition. Immediately after physical treatment, almost of all cells of P. bipes stopped swimming behavior. However, one day after treatment, about 70% of cells restarted swimming. This ratio maintained 12 day after the treatment. Settlement of stopping cells led decrease in concentration of Chla and SS. Considering these effects, we discussed mechanism of effects of physical treatment on Peridinium dynamics and counter measure preventing freshwater red tide.

Study on the Dominating Factors of Freshwater Red Tides Caused by a Dinoflagellate Peridinium bipes in a Dam Reservoir

Study on the Dominating Factors of Freshwater Red Tides Caused by a Dinoflagellate Peridinium bipes in a Dam Reservoir

The So-called Freshwater Red Tide Uroglena americana in Lake Biwa

The So-called Freshwater Red Tide Uroglena americana in Lake Biwa

Excystment patterns of the freshwater dinoflagellate Peridinium bipes (Dinophyceae) in Juam Reservoir, Korea

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 47:213-221 (2007) - doi:10.3354/ame047213 Excystment patterns of the freshwater dinoflagellate Peridinium bipes (Dinophyceae) in Juam Reservoir, Korea Baik-Ho Kim1, Myung-Hwan Park1, Soon-Jin Hwang2, Myung-Soo Han1,* 1Department of Life Science, Hanyang University, Seoul 133-791, Korea 2Department of Environmental Science, Konkuk University, Seoul 143-701, Korea *Corresponding author. Email: hanms@hanyang.ac.kr ABSTRACT: We examined seasonal variations in vegetative populations and cyst germination of the dinoflagellate Peridinium bipes Stein in reservoir water samples collected from August 2003 to March 2005, a period that included a sudden bloom of this species (September 2003 to March 2004). Monthly variations in cyst abundance and germination were tracked, and the effects of environmental factors (water temperature, pH, light and nutrients) on cyst germination were measured in the laboratory under ambient field conditions. During the bloom period, the cyst abundance of P. bipes in sediment samples fluctuated from 4 to 427 cells g–1 (wet weight), and did not show season-dependent variation. During the same period, the number of vegetative cells of P. bipes in water samples varied from 0 to 9.79 × 102 ml–1. Laboratory experiments revealed a maximum germination rate at 15.6°C, and effective germination was observed at the naturally occurring pH values of 6 to 8, but not at pH 9. Cysts obtained from samples collected at higher temperatures (over 15°C) germinated more quickly than those seeded at lower temperatures, while cysts collected in fall and early winter had a higher cumulative excystment rate than those collected in spring and summer, suggesting that cysts deposited at higher temperatures may act as a seed population for the winter blooms. These findings collectively indicate that germination of P. bipes was mainly affected by water temperature and light intensity, and not nutrient levels and pH, and further show that the bloom of P. bipes observed in Juam Reservoir was likely promoted by the presence of sufficient nutrients, relatively high excystment rates and active growth occurring under low temperature conditions. KEY WORDS: Cyst germination · Dinoflagellates · Environment · Freshwater red-tide · Peridinium bipes Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 47, No. 3. Online publication date: May 30, 2007 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2007 Inter-Research.

Long-term dynamics of freshwater red tide in shallow lake in central Japan

The aim of this study is to clarify the long-term dynamics of the red tide occurring in Lake Kawaguchi. The measurement of environmental factors and water sampling were carried out monthly at a fixed station in Lake Kawaguchi's center basin from April 1993 to March 2004. On June 26, 1995, the horizontal distribution ofPeridinium bipes was investigated using a plastic pipe, obtaining 0∼1-m layers of water column samples at 68 locations across the entire lake. P. bipes showed an explosive growth and formed a freshwater red tide in the early summer of 1995, when the nutrient level was higher than those in the other years, particularly the phosphate concentration in the surface layer. The dissolved total phosphorus (DTP) concentration was sufficient forP. bipes growth in that year. In the study of its horizontal distribution,P. bipes was found at all the locations. The numbers of cells per milliliter ranged from 67 to 5360, averaging 1094±987 cells/ml, with particularly high densities along the northern shore. Since then,P. bipes has annually averaged about 25 cells/ml in Lake Kawaguchi. We observed that the red tide caused byP. bipes correlates with a high DTP concentration in Lake Kawaguchi.

Long-Term Dynamics of Freshwater Red Tide in Shallow Lake in Central Japan

Long-Term Dynamics of Freshwater Red Tide in Shallow Lake in Central Japan

Morphology and Ecology of Peridinium bipes var. occultatum Lindem.(Dinophyceae) Forming Freshwater Red Tides in Korean Dam Reservoirs

Water blooms can be defined as the phenomenon occurring when phytoplankton, protists, and microorganisms increase abruptly to great numbers or accumulate biologically or physically, causing the color of the water to change and harming other organisms (Lee 1999; MOMAF 2000). The term red tide refers to the phenomenon of by which water bodies turn red due to the high numbers of Dinophyceae In recent times, repeated occurrences of freshwater red tides in domestic dam reservoirs, including Imha dam reservoir, have caught the attention of scientists, and in the years 2003 and 2004 serious red tides occurred in dam reservoirs all over the country, including Sangsa, Chuam, Gucheon and Miryang dam reservoirs, causing great worries not just to ecologists, but through all levels of society in Korea (KOWACO 2003). Korean freshwater red tides have been reports by Kim et al. (1987), Kang et al. (1989) and Ahn (1990). However, the first two were in fact very short abstracts rather than dissertations or reports, and the report by Ahn (1990) simply conducted research on the bacterial variation caused by red tides rather than the red tide itself. Thus we can say that there have been no actual Korean research projects directly examining freshwater red tides. Also, because the research projects mentioned above were all conducted on Soyang dam reservoir, it is also true that the amount of research done is much limited to be able to achieve complete understanding of the phenomenon of freshwater red tides in Korean dam reservoirs as a whole. However, work such as the investigation on the classification and the genotypic analysis of the organisms that cause freshwater red tides in Chuam dam reservoir, Sangsa dam reservoir and the Togyo dam reservoir by Ki et al. (2005a, b) showed that, in recent times, research on freshwater red tides in Korea has been gradually progressing. Nevertheless, research on the present level of freshwater red tide incidents and their causes is still insufficient. Therefore, it is critical that we examine the seriousness and causes of freshwater red tides in the dam reservoirs where they occur, devise appropriate countermeasures against freshwater red tides and investigate the subsequent hindrances to utilization of water resources, such as conducting bioassays Algae Volume 21(4): 433-443, 2006

Phylogenetic relationships, evolutionary origin, taxonomic status, and genetic structure of the endangered local Lower Elbe river (Germany) endemic Oenanthe conioides (Nolte ex Rchb.f.) Lange (Apiaceae): ITS and AFLP evidence

Oenanthe conioides is an endangered local endemic of the Lower Elbe river region in Germany where it is found in areas with freshwater tides. Internal transcribed spacer (ITS) and amplified fragment length polymorphism (AFLP) markers were used to investigate its phylogenetic relationships, evolutionary origin, taxonomic status, and genetic structure. Oe. conioides is most closely related to Oe. aquatica and Oe. fluviatilis, and cannot be distinguished from Oe. aquatica by ITS sequence variation. Oe. aquatica is found mainly in standing or slow-flowing freshwater habitats. The AFLP analysis indicated that Oe. conioides may constitute a monophyletic lineage nested within Oe. aquatica. Considering this result on the background of the sympatric distribution of the two species and their ecological differentiation, it is hypothesized that Oe. conioides arose sympatrically from Oe. aquatica through ecological divergence. It is concluded that Oe. conioides is best considered a subspecies of Oe. aquatica. AFLP analysis of Oe. conioides revealed low levels of genetic differentiation among populations reflecting the small geographical distance, the recent decline in population number and size, the connection of populations through the river, and their presumably high population dynamics. Considering this pattern of genetic variation, it is concluded that no individual population can be singled out as being particularly important from a genetic point of view. Also, all populations could be used as source material should the establishment of new populations or the enlargement of small populations be considered as a measure to consolidate the persistence of the species.

Application of autonomous underwater vehicle and image analysis for detecting the three-dimensional distribution of freshwater red tide Uroglena americana (Chrysophyceae)

The spatial structure of Uroglena americana was detected using an AUV equipped with a submersible microscope, video recording system and water quality monitoring sensors. U. americana colonies were enumerated via image analysis and pattern recognition methods. This quantitative technique is useful for understanding plankton assemblages, distributions, and their potential to become nuisance algal blooms.

Isolation and Characterization of Dinochrome A and B, anti‐Carcinogenic Active Carotenoids from the Fresh Water Red Tide Peridinium bipes.

Two epimeric carotenoids, named dinochromes A (2) and B (3), were isolated from the fresh water red tide Peridinium bipes, as anti-carcinogenic compounds. The stereostructure of dinochrome A and B were characterized to be (3S,5R,6R,3'S,5'R,8'R)- and (3S,5R,6R,3'S,5'R,8'S)-5',8'-epoxy-6,7-didehydro-5,6,5',8'-tetrahydro-beta,beta-carotene-3,5,3'-triol 3-O-acetate, respectively by (1)H- and (13)C-NMR, and circular dichroism (CD) data. Dinochromes A (2) and B (3) inhibit 12-O-tetradecanoyl phorbol 13-acetate (TPA)-stimulated (32)P-incorporation into the phosholipids of HeLa cells. Furthermore, dinochrome A was found to inhibit the proliferation of human malignant tumor cells, such as GOTO, OST and HeLa cells.

Blooms of the dinoflagellate Glenodinium sanguineum obtained during enclosure experiments in Lake Tovel (N. Italy)

Freshwater red tides due to dinoflagellates are less common than their marine analogues, which are usually a serious problem and can even be toxic. This was not the case for Lake Tovel in the Adamello-Brenta Natural Park (Southern Alps, Italy), where the dinoflagellate Glenodinium sanguineum Marchesoni accumulated carotenoids (astaxanthin-like compound) and caused a spectacular and regular "summer reddening", which suddenly ceased in 1964. Today Lake Tovel is a temperate, meromictic (with dimictic mixolimnion), oligotrophic mountain lake, characterised by marked water level fluctuations. G. sanguineum is still present in the lake, although with markedly lower densities in comparison to the pre-1965 period. Enclosure studies were carried out to identify the main factors regulating the blooms. In 1998, by means of phosphorus enrichments, it was possible to obtain a marked increase in numbers of G. sanguineum. Phosphorus additions in similar enclosures in 1999, when weather conditions during the summer were not optimal (mostly cloudy with frequent rainfalls), did not have the same effect, since species known to thrive in spring or under icecover developed. In summer 2000, by attenuating light in one of the enclosures, it was shown that irradiance conditions strongly interacted with phosphorus availability in determining the species that dominated the phytoplankton. In summer 2001, G. sanguineum increased again in the enclosure enriched with phosphorus. Nitrogen was observed to become a limiting factor only in conditions forced by phosphorus additions. From the first four years of in situ experiments, we concluded that phosphorus and light conditions were among the key factors controlling the proliferation and the dominance of G. sanguineum.

Isolation and characterization of dinochrome A and B, anti-carcinogenic active carotenoids from the fresh Water red tide Peridinium bipes.

Two epimeric carotenoids, named dinochromes A (2) and B (3), were isolated from the fresh water red tide Peridinium bipes, as anti-carcinogenic compounds. The stereostructure of dinochrome A and B were characterized to be (3S,5R,6R,3'S,5'R,8'R)- and (3S,5R,6R,3'S,5'R,8'S)-5',8'-epoxy-6,7-didehydro-5,6,5',8'-tetrahydro-beta,beta-carotene-3,5,3'-triol 3-O-acetate, respectively by (1)H- and (13)C-NMR, and circular dichroism (CD) data. Dinochromes A (2) and B (3) inhibit 12-O-tetradecanoyl phorbol 13-acetate (TPA)-stimulated (32)P-incorporation into the phosholipids of HeLa cells. Furthermore, dinochrome A was found to inhibit the proliferation of human malignant tumor cells, such as GOTO, OST and HeLa cells.

STUDY ON THE MECHANISM SUSTAINING THE LONG TERM FRESHWATER RED TIDE FORMED AT THE RESERVOIR TAIL

Freshwater red tide blooms are formed at the reservoir tail in many cases. Dinoflagellates such as Peridinium and Ceratium are usually causative species. These species are unique in being able to swim toward light (phototaxis). This ability makes it possible for them to swim upward during a day. Density currents formed around a plunging point of river water at the reservoir tail seem to help them accumulate around the plunging point. We have surveyed flow structure, water quality changes and diel distribution variation of red tide causing Peridinium bipes at a reservoir tail to investigate the mechanism which leads to a long term continuation of red tide bloom. A continuous surface flow directing upstream was measured at the reservoir tail and P. bipes's accumulation at the water surface and upward migration during a day were observed. Most individuals remain at the surface even during night; however, some settled down and were transported downstream by plunged river water which contains available nutrients. This partial settling seems to allow them to take up nutrient from river water without being flushed out throughly

Geotaxis in the Freshwater Dinoflagellate Peridinium bipes f. occultatum.

The characteristics of taxis in Peridinium bipes were examined using an experimental tank and a coupled microscope-CCD camera system. The vegetative cells exhibited negative geotaxis, since they swam upward irrespective of upward or downward irradiance. This behavior appeared to be the main factor in controlling the vertical migration of this species. The negative geotaxis was inferred to be caused by the distance between the center of gravity and the geometric center of the cell. We also estimated the geotactic and phototactic vertical swimming velocity of P. bipes and simulated the vertical migration of a P. bipes community with a numerical model. The model accurately reproduced the observed vertical migration pattern of the P. bipes community at irradiances over the range of 0 to 80.5μmol quanta m-2 sec-1. This model, in combination with a hydrodynamic model and a water quality model, will play a useful role in elucidating the appearance of freshwater red tides caused by P. bipes.