Checklist and morphometry of benthic cnidarians from the Fernando de Noronha Archipelago, Brazil

The Fernando de Noronha Archipelago (Pernambuco State, Brazil), a national marine park, is formed by 21 islands and islets of volcanic origin. An update of the checklist of the benthic cnidarians from some of the archipelago`s reef environments, as well as a study of their corals and calcified hydroids morphometry, was the major goal of this work. Fieldwork was undertaken in February 2005 and in April 2006 and observations were carried out at 13 stations during snorkeling and/or scuba diving up to 30 m deep. Thirty-four species of cnidarians were recorded, of which 17 are new occurrences for the studied area. When added to the species previously listed in the literature, the total number of benthic cnidarians recorded for the Archipelago increases to 57. Stephanocoenia michelini, a new occurrence of zooxanthellate coral, is worthy of mention, as well as the calcified hydroid Millepora braziliensis. Mussismilia hispida tenuisepta showed several variations among its skeletal characters that surpassed the limits of intraspecific morphological variation when compared to those of Mussismilia hispida.

Ecosystem health of Montevideo coastal zone: A multi approach using some different benthic indicators to improve a ten-year-ago assessment

A study on the benthic ecosystem health was performed to assess the environmental quality of Montevideo coastal zone, in view of the construction of a new sanitation system. Data were compared to previous research undertaken 10 years ago, and biochemical composition of organic matter, heavy metals, organic matter, phytopigments, benthic diatoms, macrofauna community structure and a biotic index (AMBI) were used as proxies. Results indicate an environmental quality-gradient, with the worst conditions within the inner stations of Montevideo Bay and an improvement towards the adjacent coastal zone. Higher levels of chromium, lead, phaeopigments, organic biopolymers and poor benthic macrofauna and diatom communities, characterised the hypertrophic innermost portion of Montevideo Bay. Data indicated a clear deterioration of the adjacent coastal zone comparatively to that observed 10 years ago. The complementary use of approaches not applied before (benthic diatoms and organic biopolymers) with those formerly applied improve our assessment of the trophic status and the environmental health of the area. (C) 2010 Elsevier B.V. All rights reserved.

Fluorimetric determination of intra- and extracellular free amino acids in the microalgae Tetraselmis gracilis (Prasinophyceae) using monolithic column in reversed phase mode

This paper describes the development and application of an RP HPLC method using a C(18) monolithic stationary phase for the separation and quantification of extra- and intracellular amino acids in a batch cultivation of the marine alga Tetraselmis gracilis. Fluorimetric detection was made after separation of the o-phthaldialdehyde 2-mercaptoethanol (OPA-2MCE) derivatives using a binary gradient elution. Separation of 19 amino acids was achieved with resolution >1.5 in about 39 min at a flow rate of 1.5 mL/min. RSD of analyses in seawater medium ranged from 0.36% for Orn (0.50 mu mol/L) to 12% for Ile (0.10 mu mol/L). The main constituents of the intracellular dissolved free amino acids (DFAAs) in the exponential growth phase were arginine (Arg), asparagine (Asn), alanine (Ala), aspartic acid (Asp), glutamic acid (Glu), serine (Ser), glycine (Gly), glutamine (Gln), and leucine (Leu). The major amino acids excreted to the media were valine (Val), Ala, Ser, and Gly. The monolithic phase facilitates the analysis by shortening the separation time and saving solvents and instrumentation costs (indeed conventional HPLC instrumentation can be used, running at lower pressures than those ones used with packed particle columns).

Implementing stepwise solvent elution in sequential injection chromatography for fluorimetric determination of intracellular free amino acids in the microalgae Tetraselmis gracilis

The concept of sequential injection chromatography (SIC) was exploited to automate the fluorimetric determination of amino acids after pre-column derivatization with ophthaldialdehyde (OPA) in presence of 2-mercaptoethanol (2MCE) using a reverse phase monolithic C(18) stationary phase. The method is low-priced and based on five steps of isocratic elutions. The first step employs the mixture methanol: tetrahydrofuran: 10 mmol L(-1) phosphate buffer (pH 7.2) at the volumetric ratio of 8:1:91; the other steps use methanol: 10 mmol L-1 phosphate buffer (pH 7.2) at volumetric ratios of 20:80, 35:65, SO:SO and 65:35. At a flow rate of 10 mu L s(-1) a 25 mm long-column was able to separate aspartic acid (Asp), glutamic acid (Glu), asparagine (Asn), serine (Ser), glutamine (Gln), glycine (Gly), threonine (Thr), citruline (Ctr), arginine (Arg), alanine (Ala), tyrosine (Tyr), phenylalanine (Phe), ornithine (Orn) and lysine (Lys) with resolution >1.2 as well as methionine (Met) and valine (Val) with resolution of 0.6. Under these conditions isoleucine (Ile) and leucine (Leu) co-eluted. The entire cycle of amino acids derivatization, chromatographic separation and column conditioning at the end of separation lasted 25 min. At a flow rate of 40 mu L s(-1) such time was reduced to 10 min at the cost of resolution worsening for the pairs Ctr/Arg and Orn/Lys. The detection limits varied from 0.092 mu mol L(-1) for Tyr to 0.51 mu mol L(-1) for Orn. The method was successfully applied to the determination of intracellular free amino acids in the green alga Tetraselmis gracilis during a period of seven days of cultivation. Samples spiked with known amounts of amino acids resulted in recoveries between 94 and 112%. (C) 2008 Elsevier B.V. All rights reserved.

Enrichment of bioactive compounds in microalgae for aquaculture

Microalgae are promising microorganisms for the production of food and fine chemicals. Several species of microalgae are used in aquaculture with the purpose of transfer bioactive compounds up to the aquatic food chain. The main objective of this project was to develop a stress–inducement strategy in order to enhance the biochemical productivity of Nannochloropsis gaditana, Rhodomonas marina and Isochrysis sp. for aquaculture purposes having in account their growth and organizational differences. In this regard, two experiments were design: the first one consisted on the alteration of overall nutrient availabilities in growth medium; and the second one comprised changes in nitrogen and sulfur concentrations maintaining the concentrations of the other nutrients present in a commercial growth medium (Nutribloom plus), which is frequently used in aquaculture. Microalgae dried biomass was characterized biochemically and elemental analysis was also performed for all samples. In first experimental design: linear trends between nutrient availability in growth media and microalgae protein content were obtained; optimum productivities of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) were attained for both R. marina and N. gaditana in growth media enriched with 1000 L L-1 of nutrient solution whereas for Isochrysis sp. the double of Nutribloom plus was needed; the decrease of glucans and total monosaccharides with nutrient availability for R. marina and Isochrysis sp. showed the occurrence of a possible depletion of carbohydrates towards lipids and proteins biosynthesis. Second experimental desing: N. gaditana exhibited the highest variation in their biochemical composition against the applied perturbation; variations observed for microalgae in their biochemical composition were reflected in their elemental stoichiometry; in N. gaditana the highest nitrogen concentrations lead to overall maximum productivities of the biochemical parameters. The results of the present work show two stress-inducement strategies for microalgae that may constitute a base for further investigations on their biochemical enhancement.

Benthic response to upwelling events off the SE Brazilian coast

The main aim of the present study was to evaluate and compare temporal responses of the benthos in 2 continental shelf areas (Cabo Frio and Ubatuba) off the SE Brazilian coast. In Cabo Frio (23 degrees S, 42 degrees W), the western boundary coastal upwelling of the South Atlantic Central Water (SACW) enhances primary productivity, potentially increasing food supply to the benthic communities via sinking of particulate organic carbon (POC). In contrast, POC fluxes in Ubatuba (23 degrees S, 45 degrees W) are expected to be comparatively lower because SACW remains subsurface. We analyzed the temporal and spatial input of phytodetritus (concentration of chlorophyll a in sediments) and the benthic microbial biomass (estimated by ATP-based carbon content in sediments). Median surface chlorophyll concentration was computed for all daily available SeaWiFS images (from 2001 and 2002) to follow chlorophyll a inputs. All parameters used to investigate benthic responses in the study areas showed consistently higher values in Cabo Frio than in Ubatuba. The results showed that benthic response to upwelling may last months, fueling the microbial communities in the Cabo Frio region.

Benthic foraminiferal distribution on the southeastern Brazilian shelf and upper slope

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

Environmental and grazing influence on spatial variability of intertidal biofilm on subtropical rocky shores

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

Vertical distribution of benthic invertebrate larvae during an upwelling event along a transect off the tropical Brazilian continental margin

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

Toxicity of the therapeutic potassium permanganate to tilapia Oreochromis niloticus and to non-target organisms Ceriodaphnia dubia (microcrustacean cladocera) and Pseudokirchneriella subcapitata (green microalgae)

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

Envenomation by a benthic Hydrozoa (Cnidaria): the case of Nemalecium lighti (Haleciidae)

A case of envenomation caused by the Nemalecium lighti is described. The hydrozoan species lives in many kinds of substrates, being quite common in tropical shallow water. The patient, a marine biologist, had contact with the animal in two different opportunities while snorkeling. Both contacts produced erythematous and highly pruriginous papules in exposed areas of the body. The signs and symptoms persisted for a week and healed without sequellae. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Differential benthic occupation by crabs in the Ubatuba bay, São Paulo, Brazil

The goal of this work was to examine the occurrence of brachyurans in soft bottom sublittoral habitats and their association with some environmental factors. The relative abundance of crabs in two depth strata (from 4.5 to 9 m and from 9 to 18 m) was quantified. Crabs were collected with an otter-trawl with 3.7 m of mouth opening and 12-mm mesh in the cod end. Monthly sampling, consisted of a single trawl in each stratum during a 1-yr period, were carried out. Fifteen brachyuran and six anomuran species were found, including Callinectes ornatus Ordway, 1863; Callinectes danae Smith, 1869; Hepatus pudibundus (Herbst, 1785); Libinia spinosa H. Milne-Edwards, 1834; Persephona punctata (Linnaeus, 1758), and P. mediterranea (Herbst, 1794), which were the most abundant and frequent in the area. The most abundant swimming crabs in both strata were C. ornatus and C, dan(re. Size differences in C. ornatus were observed between strata, suggesting a spatial separation of juveniles and adult crabs.

Benthic macroinvertebrates in the Paranapanema reservoir cascade (southeast Brazil)

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

Controlling factors of benthic macroinvertebrates distribution in a small tropical pond, lateral to the Paranapanema River (São Paulo, Brazil).

The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; Methods: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. Results: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; Conclusions: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.

Colonization of rocky and leaf pack substrates by benthic macroinvertebrates in a stream in southeast Brazil.

A comparative analysis was conducted of the colonization by benthic macroinvertebrates of rocky and leaf pack substrates, both natural and artificial. This colonization was evaluated by season, with the objective of ascertaining the influence of rainfall on the rate of colonization. The total density of macroinvertebrates after 21 days of colonization was significantly greater in the dry than in the wet season. When the substrate types were compared, artificial leaf pack substrate presented the smallest density for both seasons. In the wet season, Chironomidae, Leptohyphidae, Hydropsychidae, Elmidae, immature stages of Trichoptera, and Hydroptilidae showed a more representative density. In the dry season, Chironomidae, Baetidae and Oligochaeta were the most abundant taxa. The artificial rocky substrate used in this experiment was the most appropriate, due to its resemblance with natural substrate conditions in terms of the maintenance of the structural integrity of the substrate throughout the experimental period. Successional and seasonal effects were of great relevance, playing an important role in the colonization process.