Some Aspects Of Phytoplankton Blooms In Relation To Pelagic Fishes

The present study was undertaken to observe the phytoplankton (distones,dinoflageliates,and blue green algae) blooms occurring along the south west coast of India at various seasons from February 1982 to august 1984.The centers selected for collection and observation were off Quilon, off Alleppey ,off Calicut. A total number of 25 phytoplankton blooms were studied. Characterisation of phytoplankton blooms include observing the cell counts from the day of its appearance to its day of disappearance. The appearance ,duration and locality of the blooms were also noted

Algal Blooms and Associated Bacteria along the Southwest Coast of India

It is essential to understand how the distribution and composition of microalgae as well as dynamics of HABs in economically important shelf seas relate to the particular physico-chemical and biological properties of the water column in which they live. In view of the importance of southwest coast of India, which is considered as one of the most biologically productive areas in the world, regular monitoring of distribution and abundance of microalgae is important. The present work is concentrated on the estuarine and coastal open sea stations along the southwest coast of India. In order to get further insights into the abiotic factors governing bloom dynamics, the physicochemical parameters that regulated three particular bloom events during this period were studied. Bearing in mind the role of bacterial fauna associated with algal blooms as a biological factor in regulating its dynamics, isolation of bacteria associated with the algal blooms, their identification, enumeration, and ability to produce extracellular enzymes have been duly incorporated into this study

Jellyfish.

Proporciona una información básica para conocer las medusas, incluyendo su hábitat, la dieta, cómo se reproducen y las características físicas. El texto tiene dos niveles de dificultad y dos tamaños de letra para proporcionar una base para una mejor lectura. El segundo nivel es el de mayor dificultad con un vocabulario apropiado pensado para lectores más expertos. Tiene glosario.

Sediment fingerprinting as an environmental forensics tool explaining cyanobacteria blooms in lakes

Cyanobacteria (blue-green algae) blooms in water bodies present serious public health issues with attendant economic and ecological impacts. Llyn Tegid (Lake Bala) is an important conservation and amenity asset within Snowdonia National Park, Wales which since the mid-1990s has experienced multiple toxic cyanobacteria blooms threatening the ecology and tourism-dependent local economy. Multiple working hypotheses explain the emergence of this problem, including climate change, land management linked to increased nutrient flux, hydromorphological alterations or changing trophic structure - any of which may operate individually or cumulatively to impair lake function. This paper reports the findings of a sedimentfingerprinting study using dated lake cores to explore the linkages between catchment and lake management practices and the emergence of the algal blooms problem. Since 1900 AD lake bed sedimentation rates have varied from 0.06 to 1.07 g cm−2 yr−1, with a pronounced acceleration since the early 1980s. Geochemical analysis revealed increases in the concentrations of total phosphorus (TP), calcium and heavy metals such as zinc and lead consistent with eutrophication and a rising pollution burden, particularly since the late 1970s. An uncertainty-inclusive sedimentfingerprinting approach was used to apportion the relative fluxes from the major catchment land cover types of improved pasture, rough grazing, forestry and channel banks. This showed improved pasture and channel banks are the dominant diffuse sources of sediment in the catchment, though forestry sources were important historically. Conversion of rough grazing to improved grassland, coupled with intensified land management and year-round livestock grazing, is concluded to provide the principal source of rising TP levels. Lake Habitat Survey and particle size analysis of lake cores demonstrate the hydromorphological impact of the River Dee Regulation Scheme, which controls water level and periodically diverts flow into Llyn Tegid from the adjacent Afon Tryweryn catchment. This hydromorphological impact has also been most pronounced since the late 1970s. It is concluded that an integrated approach combining land management to reduce agricultural runoff allied to improved water level regulation enabling recovery of littoral macrophytes offers the greatest chance halting the on-going cyanobacteria issue in Llyn Tegid.

The phenology of phytoplankton blooms: ecosystems indicators from remote sensing

Remote sensing offers many advantages in the development of ecosystem indicators for the pelagic zone of the ocean. Particularly suitable in this context are the indicators arising from time series that can be constructed from remotely sensed data. For example, using ocean-colour radiometry, the phenology of phytoplankton blooms can be assessed. Metrics defined in this way show promise as informative indicators for the entire pelagic ecosystem. A simple phytoplankton–substrate model, with forcing dependent on latitude and day number is used to explore the qualitative features of bloom phenology for comparison with the results observed in a suite of 10-year time series of chlorophyll concentration, as assessed by remote sensing, from the Northwest Atlantic Ocean. The model reveals features of the dynamics that might otherwise have been overlooked in evaluation of the observational data.

The extract of the jellyfish Phyllorhiza punctata promotes neurotoxic effects

Phyllorhiza punctata (P. punctata) is a jellyfish native to the southwestern Pacific. Herewith we present the biochemical and pharmacological characterization of an extract of the tentacles of P. punctata. The tentacles were subjected to three freezethaw cycles, homogenized, ultrafiltered, precipitated, centrifuged and lyophilized to obtain a crude extract (PHY-N). Paralytic shellfish poisoning compounds such as saxitoxin, gonyautoxin-4, tetrodotoxin and brevetoxin-2, as well as several secretory phospholipase A2 were identified. PHY-N was tested on autonomic and somatic neuromuscular preparations. In mouse vas deferens, PHY-N induced phasic contractions that reached a peak of 234 +/- 34.7% of control twitch height, which were blocked with either 100 mu m of phentolamine or 1m m of lidocaine. In mouse corpora cavernosa, PHY-N evoked a relaxation response, which was blocked with either L-NG-Nitroarginine methyl ester (0.5 m m) or 1m m of lidocaine. PHY-N (1, 3 and 10 mu g ml(-1)) induced an increase in tonus of the biventercervicis neuromuscular preparation that was blocked with pre-treatment of galamine (10 mu m). Administration of 6 mg kg(-1) PHY-N intramuscularly produced death in broilers by spastic paralysis. In conclusion, PHY-N induces nerve depolarization and nonspecifically increases neurotransmitter release. Copyright (C) 2011 John Wiley & Sons, Ltd.

Skin lesions in envenoming by cnidarians (Portuguese man-of-war and jellyfish): etiology and severity of accidents on the Brazilian coast

This work attempts to establish dermatological identification patterns for Brazilian enidarian species and it probable correlation with envenoming, severity In all observational prospective study, one hundred and twenty-eight patients from the North Coast re-ion of São Paulo State, Brazil were seen between 2002 and 2008. About 80% of these Showed only local effects (erythema, edema, and pain) with small, less than 20 cm, oval or round skin marks and impressions from Small tentacles. Approximately 20% of the victims had long, more than 20 cm, linear and crossed marks with frequent systemic phenomena, such as malaise, vomiting, dyspnea, and tachycardia. The former is compatible with the common hydromedusa from Southeast and Southern Brazil (Olindias sambaquiensis). The long linear marks with intense pain and systemic phenomena are compatible with envenoming, by the box jellyfish Tamoya haplonema and Chiropsalmus quadrumanus and the hydrozoan Portuguese man-of-war (Physalis physalis). There was an association between Skin marks and probable accident etiology. This simple observation rule can be indicative of severity as the Cubozoa Class (box jellyfish) and Portuguese man-of-war cause the most severe accidents. In such cases, medical attention, including intensive care, is important, as the systemic manifestations call be associated with death.

The climatic rhythm and blooms of cyanobacteria in a tropical reservoir in São Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Eutrophication and macroalgal blooms in temperate and tropical coastal waters: nutrient enrichment experiments with Ulva spp.

Receiving coastal waters and estuaries are among the most nutrient-enriched environments on earth, and one of the symptoms of the resulting eutrophication is the proliferation of opportunistic, fast-growing marine seaweeds. Here, we used a widespread macroalga often involved in blooms, Ulva spp., to investigate how supply of nitrogen (N) and phosphorus (P), the two main potential growth-limiting nutrients, influence macroalgal growth in temperate and tropical coastal waters ranging from low- to high-nutrient supplies. We carried out N and P enrichment field experiments on Ulva spp. in seven coastal systems, with one of these systems represented by three different subestuaries, for a total of nine sites. We showed that rate of growth of Ulva spp. was directly correlated to annual dissolved inorganic nitrogen (DIN) concentrations, where growth increased with increasing DIN concentration. Internal N pools of macroalgal fronds were also linked to increased DIN supply, and algal growth rates were tightly coupled to these internal N pools. The increases in DIN appeared to be related to greater inputs of wastewater to these coastal waters as indicated by high delta 15N signatures of the algae as DIN increased. N and P enrichment experiments showed that rate of macroalgal growth was controlled by supply of DIN where ambient DIN concentrations were low, and by P where DIN concentrations were higher, regardless of latitude or geographic setting. These results suggest that understanding the basis for macroalgal blooms, and management of these harmful phenomena, will require information as to nutrient sources, and actions to reduce supply of N and P in coastal waters concerned.

CLEANER SHRIMP (CARIDEA: PALAEMONIDAE) ASSOCIATED WITH SCYPHOZOAN JELLYFISH

Shrimp are found in association with many hosts (sponges, anthozoans, mollusks, echinoids, ascidians and fish). Shrimp are rarely observed in association with jellyfish. The interaction between the cleaner shrimp Periclimenes paivai and jellyfish is poorly known, with only one published report for Brazilian waters. We add new information about this association, based on field and laboratory observations. Shrimp were collected from three locations on the coast Of Sao Paulo State (Cananeia, Santos and Sao Sebastiao) and from two species of scyphozoan rnedusae: Chrysaora lactea and Lychnorhiza lucerna. We classify the association as facultative commensalism, since the shrimp gain protection and probably feed on mucus produced by the jelly fish. The maximum carapace length of the shrimp collected was 9.2 min. Medusa bel I diameter ranged between about 10 and 19 cm for C. lactea and between 4.5 and 25 cm for L. lucerna. We also provide a list of records of Periclimenes in association with different scyphornedUsae, and additional information on the size and coloration of P. paivai.

Morphological and molecular studies of Sphaerospermopsis torques-reginae (Cyanobacteria, Nostocales) from South American water blooms

Sphaerospermopsis torques-reginae (Komarek) Werner, Laughinghouse IV, Fiore & Sant'Anna comb. nov. was originally described as Anabaena torques-reginae Komarek from planktonic populations of Cuban eutrophic environments, characterized by twisted trichomes with spherical akinetes adjacent to the heterocytes. Recently, using molecular analyses, all planktonic Anabaena Bory ex Bornet & Flahault morphospecies were transferred into the genus Dolichospermum (Ralfs ex Bornet & Flahault) Wacklin el al., including Dolichospermum torques-reginae (Komarek) Wacklin et al. However, by a polyphasic characterization of strains of Anabaena reniformis Lemmermann and Aphanizomenon aphanizomenoides (Forti) Horecka & Komarek (=Anabaena aphanizomenoides Forti), these planktonic species were reclassified into Sphaerospermopsis Zapomelova et al. Our study's main objective was to characterize morphologically and molecularly cyanobacterial populations identified as Dolichospermum torques-reginae, observed in different aquatic ecosystems in South America. The 16S rRNA gene of two Dolichospermum torques-reginae strains (ITEP-024 and ITEP-026) was sequenced and phylogenetically analyzed for the first time. The morphological and phylogenetic analyses demonstrated the affiliation of the studied populations with the genus Sphaerospermopsis and, consequently, were denominated as Sphaerospermopsis torques-reginae. Furthermore, geographic distribution, ecology, and toxicity of the species are discussed. It was observed in different aquatic environments, natural and artificial, tropical and subtropical in Brazil, temperate in Argentina, and tropical in Colombia, suggesting a wide distribution in South America. It normally occurred in dense freshwater blooms, although it was also found in water with low salinity. Sphaerospermopsis torques-reginae toxic blooms have been reported in tropical water bodies in northeastern Brazil.

Proteomic characterisation of toxins isolated from nematocysts of the South Atlantic jellyfish Olindias sambaquiensis

Surprisingly little is known of the toxic arsenal of cnidarian nematocysts compared to other venomous animals. Here we investigate the toxins of nematocysts isolated from the jellyfish Olindias sambaquiensis. A total of 29 unique ms/ms events were annotated as potential toxins homologous to the toxic proteins from diverse animal phyla, including conesnails, snakes, spiders, scorpions, wasp, bee, parasitic worm and other Cnidaria. Biological activities of these potential toxins include cytolysins, neurotoxins, phospholipases and toxic peptidases. The presence of several toxic enzymes is intriguing, such as sphingomyelin phosphodiesterase B (SMase B) that has only been described in certain spider venoms, and a prepro-haystatin P-IIId snake venom metalloproteinase (SVMP) that activates coagulation factor X, which is very rare even in snake venoms. Our annotation reveals sequence orthologs to many representatives of the most important superfamilies of peptide venoms suggesting that their origins in higher organisms arise from deep eumetazoan innovations. Accordingly, cnidarian venoms may possess unique biological properties that might generate new leads in the discovery of novel pharmacologically active drugs.

Evaluation of Iron as a Triggering Factor for Red Tide Blooms

We have examined the relationship between Fe and blooms of the toxic dinoflagellate Alexandrium tamarense (Balech) (formerly Gonyaulax tamarensis var. excavata (Lebour)) using a chemical method that estimates the biological availability of Fe in seawater. The Fe requirement for optimal growth of A. tamarense in sequential batch culture (ca 3 nM 'available' Fe) was compared with Fe concentrations in waters of the Gulf of Maine, USA. Results indicated that Fe did not limit growth of the organism in nearshore coastal waters or over Georges Bank, but that the organism may have been Fe-limited in Gulf of Maine basin waters. The distribution of A. tamarense in the Gulf of Maine is consistent with these Fe data. Red tide outbreaks in the nearshore environment did not correlate with changes in total Fe or the estimated Fe availability. Although Fe did not appear to trigger outbreaks of A. tamarense in Maine coastal waters, the findings are consistent with suggestions that pulsed inputs of Fe may be important for the development of toxic dinoflagellate blooms in regions (e.g. Florida) where outbreaks are initiated offshore.