Nutrients removed by Kappaphycus alvarezii (Rhodophyta, Solieriaceae) in integrated cultivation with fishes in re-circulating water

The potential of the red alga Kappaphycus alvarezii to remove nutrients was tested to treat effluents of Trachinotus carolinus fish cultivation, and the production of carrageenan in this condition was analyzed. Experiments were conducted in four tanks of 8000 L with approximately 1200 fishes of 30 g each integrated with three tanks of 100 L with 700 g of K. alvarezii, as initial biomass per tank. Seawater was re-circulated between tanks with seaweed and with fish. As a control, three tanks with seawater circulating in an open system were utilized. Seawater samples were collected daily for 10 days and concentrations of nitrate, nitrite, ammonium and phosphate were determined in the inflow and outflow water of the tanks. Significant differences between both collecting points were considered as nutrient removal by the seaweed. Growth rates and carrageenan yields were also analyzed in seaweed cultivated in seawater and in effluents. Growth rates of seaweed cultivated in tanks were lower than those obtained in open sea and in laboratory cultivation. Effluents had concentrations of nitrate and nitrite ca. 100 times higher than in the control. Maximum values of nutrient removal on effluents were: nitrate= 18.2%; nitrite =50.8%; ammonium =70.5% and phosphate =26.8%. All plants survived throughout the experimental period, but some developed ""ice-ice"", a disease associated with physiological stress. After the experimental period, some plants selected and cultivated in open sea presented higher growth rates in 40 days, indicating nutrient storage. No significant differences between carrageenan yields of K alvarezii cultivated in seawater and in the effluents were observed. Our results show that K. alvarezii can be utilized as a biofilter for fish cultivation effluents, reducing the eutrophication process and can also be processed for carrageenan production, which provides an additional benefit to the fisheries. (C) 2008 Elsevier B.V. All rights reserved.

Bryozoan biodiversity in Saint Peter and Saint Paul Archipelago, Brazil

Among the marine invertebrate groups recorded from oceanic islands, bryozoans stand out because they can live and reproduce in suboptimal habitats, which may enhance their dispersal capabilities. This study aimed to update the checklist of bryozoans known from the Saint Peter and Saint Paul Archipelago (ASPSP) and discusses their distribution. During the five expeditions conducted between 2007 and 2009, 22 species were found, of which 16 were new occurrences for the archipelago. The bryozoans were collected from different biotic (algae and invertebrates) and abiotic (rocks, rubble and wrecks) substrata. The bryozoan community in ASPSP includes: eight new and probably endemic species, five species that belong to widespread species complexes, three species known only from the Brazilian coast, two species reported from the Western Atlantic and one species recorded from oceanic islets in the Atlantic. Additionally, three species are widespread in tropical to subtropical waters. Margaretta buski can be highlighted as the most conspicuous and abundant species between 1045 m deep and acts as an "ecosystem engineer".

Cradoscrupocellaria, a new bryozoan genus for Scrupocellaria bertholletii (Audouin) and related species (Cheilostomata, Candidae): taxonomy, biodiversity and distribution

A new genus, Cradoscrupocellaria n. gen., is erected for Scrupocellaria bertholletii Audouin, 1826), reported as widespread in tropical and subtropical waters. Here we select a neotype of this species in order to establish its identity and distinguish it from morphologically similar species. We include redescriptions and figures of additional species now assigned to this new genus: Cradoscrupocellaria curacaoensis (Fransen, 1986) n. comb., Cradoscrupocellaria hirsuta (Jullien & Calvet, 1903) n. comb., and Cradoscrupocellaria macrorhyncha (Gautier, 1962) n. comb. Five additional species are assigned to the genus: Cradoscrupocellaria ellisi (Vieira & Spencer Jones, 2012) n. comb., Cradoscrupocellaria nanshaensis (Liu, 1991) n. comb., Cradoscrupocellaria reptans (Linnaeus, 1758) n. comb., Cradoscrupocellaria serrata (Waters, 1909) n. comb., and Cradoscrupocellaria tenuirostris (Osburn, 1950) n. comb. Eighteen new species are described: Cradoscrupocellaria aegyptiana n. sp., Cradoscrupocellaria arisaigensis n. sp., Cradoscrupocellaria atlantica n. sp., Cradoscrupocellaria calypso n. sp., Cradoscrupocellaria floridana n. sp., Cradoscrupocellaria galapagensis n. sp., Cradoscrupocellaria gautieri n. sp., Cradoscrupocellaria gorgonensis n. sp., Cradoscrupocellaria hastingsae n. sp., Cradoscrupocellaria insularis n. sp., Cradoscrupocellaria jamaicensis n. sp., Cradoscrupocellaria lagaaiji n. sp., Cradoscrupocellaria macrorhynchoides n. sp., Cradoscrupocellaria makua n. sp., Cradoscrupocellaria marcusorum n. sp., Cradoscrupocellaria normani n. sp., Cradoscrupocellaria odonoghuei n. sp., and Cradoscrupocellaria osburni n. sp.

Laser Optical Plankton Counter and Zooscan intercomparison in tropical and subtropical marine ecosystems

Two recently developed instruments, the Laser Optical Plankton Counter (LOPC) and the Zooscan, have been applied to study zooplankton biomass size spectra in tropical and subtropical marine ecosystems off Brazil. Both technologies rely on optical measurements of particles and may potentially be used in zooplankton monitoring programs. Vertical profiles of the LOPC installed in a 200 mu m ring net have been obtained from diverse environmental settings ranging from turbid and nearshore waters to oligotrophic open ocean conditions. Net samples were analyzed on the Zooscan and counted under a microscope. Particle biovolume in the study area estimated with the LOPC correlated with plankton displacement volume from the net samples, but there was no significant relationship between total areal zooplankton biomass determined with LOPC and the Zooscan. Apparently, normalized biomass size spectra (NBSS) of LOPC and Zooscan overlapped for particles in the size range of 500 to 1500 mu m in equivalent spherical diameter (ESD), especially at open ocean stations. However, the distribution of particles into five size classes was statistically different between both instruments at 24 of 28 stations. The disparities arise from unequal flow estimates, from different sampling efficiencies of LOPC tunnel and net for large and small particles, and possibly from the interference of non-zooplankton material in the LOPC signal. Ecosystem properties and technical differences therefore limit the direct comparability of the NBSS slopes obtained with both instruments during this study, and their results should be regarded as complementary.

Estuarine and oceanic influences on copepod abundance and production of a subtropical coastal area

We investigated the influence of nutrient-rich oceanic waters in comparison to the estuarine outflow from Santos Bay (SE Brazil) on copepod abundance and production on the adjacent inner shelf. Zooplankton samples were collected with a Multinet in spring 2005 and in summer 2006. Copepod biomass was derived from length-weight regressions, and growth rates were estimated from empirical models. Altogether, 58 copepod taxa were identified. The highest abundances were due to small-sized organisms including nauplii, oncaeids and copepodids of paracalanids and clausocalanids. Biomass and secondary production mirrored copepod abundance, with Temora copepodids accompanying the above-mentioned taxa as major contributors. The contribution of naupliar biomass and production was low (2.2 and 3.8% of the total, respectively). The influence of the Santos Bay outflow was observed only in spring, when Coastal Water (CW) dominated at the study site; whereas in summer the inner shelf was occupied by CW in the surface layer and the oceanic South Atlantic Central Water (SACW) in the bottom layer. The SACW intrusion had more of an influence for the increase in copepod production than the Santos Bay plume. The distribution and dynamics of the oceanic water masses seemed to be the most important influence on copepod diversity and production at this subtropical site.

Variability of the subtropical shelf front off eastern South America: Winter 2003 and summer 2004

Hydrographic data collected during surveys carried out in austral winter 2003 and summer 2004 are used to analyze the distributions of temperature (T) and salinity (S) over the continental shelf and slope of eastern South America between 27 degrees S and 39 degrees S. The water mass structure and the characteristics of the transition between subantarctic and subtropical shelf water (STSW), referred to as the subtropical shelf front (STSF), as revealed by the vertical structure of temperature and salinity are discussed. During both surveys, the front intensifies downward and extends southwestward from the near coastal zone at 33 degrees S to the shelf break at 36 degrees S. In austral winter subantarctic shelf water (SASW), derived from the northern Patagonia shelf, forms a vertically coherent cold wedge of low salinity waters that locally separate the outer shelf STSW from the fresher inner shelf Plata Plume Water (PPW) derived from the Rio de la Plata. Winter T-S diagrams and cross-shelf T and S distributions indicate that mixtures of PPW and tropical water only occur beyond the northernmost extent of pure SASW, and form STSW and an inverted thermocline characteristic of this region. In summer 2004, dilution of Tropical water (TW) occurs at two distinct levels: a warm near surface layer, associated to PPW-TW mixtures, similar to but significantly warmer than winter STSW, and a colder (T similar to 16 degrees C) salinity minimum layer at 40-50 m depth, created by SASW-STSW mixtures across the STSF. In winter, the salinity distribution controls the density structure creating a cross-shore density gradient, which prevents isopycnal mixing across the STSF. Temperature stratification in summer induces a sharp pycnocline providing cross-shelf isopycnal connections across the STSF. Cooling and freshening of the upper layer observed at stations collected along the western edge of the Brazil Current suggest offshore export of shelf waters. Low T and S filaments, evident along the shelf break in the winter data, suggest that submesoscale eddies may enhance the property exchange across the shelf break. These observations suggest that as the subsurface shelf waters converge at the STSF, they flow southward along the front and are expelled offshore, primarily along the front axis. (C) 2008 Elsevier Ltd. All rights reserved.

Biological, physical and chemical properties at the Subtropical Shelf Front Zone in the SW Atlantic Continental Shelf

The physical aspects of the Subtropical Shelf Front (STSF) for the Southwest Atlantic Continental Shelf were previously described. However, only scarce data on the biology of the front is available in the literature. The main goal of this paper is to describe the physical, chemical and biological properties of the STSF found in winter 2003 and summer 2004. A cross-section was established at the historically determined location of the STSF. Nine stations were sampled in winter and seven in summer. Each section included a series of conductivity-temperature-depth (CTD) stations where water samples from selected depths were filtered for nutrient determination. Surface samples were taken for chlorophyll a (Chl-a) determination and plankton net tows carried out above and below the pycnocline. Results revealed that winter was marked by an inner-shelf salinity front and that the STSF was located on the mid-shelf The low salinity waters in the inner-shelf indicated a strong influence of freshwater, with high silicate (72 mu M), suspended matter (45 mg l(-1)), phosphate (2.70 mu M) and low nitrate (1.0 mu M) levels. Total dissolved nitrogen was relatively high (22.98 mu M), probably due to the elevated levels of organic compound contribution close to the continental margin. Surface Chl-a concentration decreased from coastal well-mixed waters, where values up to 8.0 mg m(-3) were registered, to offshore waters. Towards the open ocean, high subsurface nutrients values were observed, probably associated to South Atlantic Central Waters (SACW). Zooplankton and ichthyoplankton abundance followed the same trend; three different groups associated to the inner-, mid- and outer-shelf region were identified. During summer, diluted waters extended over the shelf to join the STSF in the upper layer; the concentration of inorganic nutrients decreased in shallow waters; however, high values were observed between 40 and 60 m and in deep offshore waters. Surface Chl-a ranged 0.07-1.5 mg m(-3); winter levels were higher. Three groups of zoo and ichthyoplankton, separated by the STSF, were also identified. Results of the study performed suggest that the influence of freshwater was stronger during winter and that abundance distribution of Chl-a, copepods and ichthyoplankton was related to the Plata Plume Waters (PPW), rather than to the presence of the STSF. During summer, when the presence of freshwater decreases, plankton interactions seem to take place in the STSF. (C) 2008 Elsevier Ltd. All rights reserved.

Seasonal contrasts in abundance and reproductive parameters of Penilia avirostris (Cladocera, Ctenopoda) in a coastal subtropical area

We studied the population dynamics and the reproductive biology of Penilia avirostris during three consecutive years on the inner shelf off Ubatuba, Brazil. Penilia avirostris individuals and its eggs and embryos were counted, measured, and classified into stages. The species occurred throughout the studied period, in a wide temperature range (14.8-28.2A degrees C). Cladoceran densities were usually higher (> 2,000 ind m(-3)) in warm seasons, when the water column was stratified as a consequence of bottom intrusions of the cold- and nutrient-rich South Atlantic Central Water. Juveniles, non-reproducing females, and parthenogenic females were the dominant developmental stages. Males and gamogenic females were rare and only occurred when females reached peak abundances. This suggests that in tropical and subtropical coastal seas gamogenesis in P. avirostris is not as common as in temperate seas, but may play a significant role in the density-dependent control of the population preceding unfavourable periods.

Benthic responses to organic matter variation in a subtropical coastal area off SE Brazil

Organic matter quality, expressed as the proportion of chlorophyll a (Chl a) to degraded organic material (i.e. phaeopigments), is known to influence the structure of benthic associations and plays an important role in the functioning of the ecosystem. This study investigates the vertical distribution of microbial biomass, meiofauna and macrofauna with respect to organic matter variation in Ubatuba, Brazil, a southeastern, subtropical coastal area. On three occasions, samples were collected in exposed and sheltered stations, at high and low hydrodynamic conditions. We hypothesize that benthic assemblages will have high meio- and macrofaunal densities and high microbial biomass at the sediment surface at the sheltered site, and lower and vertically homogeneous microbial biomass and densities of meio- and macrofauna are expected at the exposed site. The accumulation of fresh organic matter at the sediment surface was observed at both stations over the three sampling dates, which contributed to the higher densities of meiofauna in the first layers of the sediment column. Macrofauna followed the same trend only at the exposed station, but changes in the number of species, biodiversity and feeding groups were registered for both stations. Microbial biomass increased at the sheltered station over the three sampling dates, whereas at the exposed station, microbial biomass was nearly constant. Physical exposure did not influence organic matter loading at the sites and therefore did not affect overall structure of benthic assemblages, which negates our original hypothesis. Most of the benthic system components reacted to organic matter quality and quantity, but relationships between different-sized organisms (i.e. competition and/or predation) may explain the unchanged microbial profiles at the exposed site and homogeneous vertical distribution of macrofauna at the sheltered site. In conclusion, the high quality of organic matter was a crucial factor in sustaining and regulating the benthic system, but coupled results showed that interactions between micro-, meio- and macrofauna can be highly complex.

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.

Spatial and temporal patterns in size and maturation of Loligo plei and Loligo sanpaulensis (Cephalopoda: Loliginidae) in southeastern Brazilian waters, between 23 degrees S and 27 degrees S

Patterns of population dynamics of Loligo plei and Loligo sanpaidensis in Southeastern Brazil were investigated with samples obtained from commercial catches and research cruises from 1999 to 2000 and from 2002 to 2003. Size and maturity Structure of the two species varied according to depth and season. Body size decreased with depth for L plei, whereas for L. sanpaidensis size increased with depth LIP to 100 m and decreased again in deeper areas. GSI and incidence of mature animals decreased with depth in both species. L. plei females matured at a larger size in summer, while size at maturity in L. sanpaulensis was greater in autumn. For L. plei, reproductive events Occurred in the late winter and spring, in depths up to 40 m, and during summer in inshore waters. L. sanpaidensis increased reproductive activity ill Summer, winter and spring between depths of 30 and 80 Ill. The presence of high proportions of immature Squid offshore Suggests that juveniles might develop in these areas and, upon maturation, migrate back to inshore waters to spawn, particularly in spring and Summer. However, differences found in aggregation patterns in different depth strata, as well as the seasonal differences found in the size structure of L. plei and L. sanpaidensis, Could ultimately be due to Changes in the water Column related to food availability. Considering that L. plei and L. sanpaidensis are both caught as by-catch by shrimp trawlers throughout file year, we also discuss hypotheses on the life cycle of the species and its implications for fishery management. We recommend measures to protect squid spawning grounds by creating spring and summer protected areas where trawling would be prohibited until 60 m depth, i.e. in the area and time of year when mature individuals concentrate.

Bacterial and phytoplankton dynamics in a sub-tropical estuary

Heterotrophic bacterial and biomass, production, specific growth rates and growth efficiencies were studied in July 2001 and January 2002 during both spring and neap tides, along a tidal cycle, at three sites in a subtropical estuary. Major freshwater inputs located in the Northern region led to differences in both and bacterioplankton biomass and activity along the estuary. While in the Northern region is light-limited, with mean production (PP) between 1.1 and 1.9 mu g C l(-1) h(-1) and mean specific growth rates (PSG) between 0.14 and 0.16 d(-1), the Southern region registered values as high as 24.7 mu g C l(-1) h(-1) for PP and 2.45 d(-1) (mean PP between 3.4 and 7.3 mu g C l(-1) h(-1); mean PSG between 0.28 and 0.57 d(-1)). On the other hand, maximum bacterial production (BP: 63.8 mu g C l(-1) h(-1)) and specific growth rate (BSG: 32.26 d(-1)) were observed in the Northern region (mean BP between 3.4 and 12.8 mu g C l(-1) h(-1); mean BSG between 1.98 and 6.67 day(-1)). These bacterial activity rates are among the highest recorded rates in estuarine and coastal waters, indicating that this system can be highly heterotrophic, due to high loads of allochthonous carbon (mainly derived from mangrove forest). Our results also showed that, despite that BP rates usually exceeded PP, in the Southern region BP may be partially supported (similar to 45%) by PP, since a significant regression was observed between BP and PP (r = 0.455, P < 0.001).

Life cycle and reproductive traits of marine podonids (Cladocera, Onychopoda) in a coastal subtropical area

We studied the temporal distribution and reproductive biology of marine podonids during two consecutive years off Ubatuba, southeast coast of Brazil. Podonid specimens and their eggs and embryos were counted, measured and classified into categories. Pseudevadne tergestina was the most abundant species, and was more abundant in surface layers, in warm seasons, when the water column was stratified because of bottom intrusions of the cold and nutrient-rich South Atlantic Central Water (SACW) onto the inner shelf. Evadne spinifera had a similar temporal and vertical distribution, but with lower abundance and frequency. Pleopis schmackeri did not show a clear seasonal distribution, but preferred bottom layers. Pleopis polyphemoides and Podon intermedius occurred in low abundances, and only under SACW influence. Parthenogenetic females were dominant among all podonid species. Gamogenetic females of P. polyphemoides and P. intermedius were observed, but males of neither species occurred. This suggests that in tropical and subtropical regions, P. tergestina, E. spinifera and P. schmackeri reproduce through parthenogenesis during most of the year.

The effects of river discharge and seasonal winds on the shelf off southeastern South America

The Rio de la Plata waters form a low salinity tongue that affects the circulation, stratification and the distributions of nutrients and biological species over a wide extent of the adjacent continental shelf. The plume of coastal waters presents a seasonal meridional displacement reaching lower latitudes (28,S) during austral winter and 32 degrees S during summer. Historical data suggests that the wind causes the alongshore shift, with southwesterly (SW) winds forcing the plume to lower latitudes in winter while summer dominant northeasterly (NE) winds force its southward retreat. To establish the connection between wind and outflow variations on the distribution of the coastal waters, we conducted two quasi-synoptic surveys in the region of Plata influence on the continental shelf and slope of southeastern South America, between Mar del Plata, Argentina and the northern coast of Santa Catarina, Brazil. We observed that: (A) SW winds dominating in winter force the northward spreading of the plume to low latitudes even during low river discharge periods; (B) NE winds displace the plume southward and spread the low salinity waters offshore over the entire width of the continental shelf east of the Plata estuary. The southward retreat of the plume in summer leads to a volume decrease of low salinity waters over the shelf. This volume is compensated by an increase of Tropical waters, which dominate the northern shelf. The subsurface transition between Subantarctic and Subtropical Shelf Waters, the Subtropical Shelf Front, and the subsurface water mass distribution, however, present minor seasonal variations. Along shore winds also influence the dynamics and water mass variations along the continental shelf area. In areas under the influence of river discharge, Subtropical Shelf Waters are kept away from the coastal region. When low salinity waters retreat southward, NE winds induce a coastal upwelling system near Santa Marta Cape. In summer, solar radiation promotes the establishment of a strong thermocline that increases buoyancy and further enhances the offshore displacement of low salinity waters under the action of NE winds. (C) 2008 Elsevier Ltd. All rights reserved.

Benthic foraminiferal assemblages of the South Brazil: Relationship to water masses and nutrient distributions

Using distributions of benthic Foraminifera and bottom-water variables (depth, salinity, temperature, oxygen, suspended matter, organic matter, phosphate, silicate, nitrite, and nitrate), we investigated movements of water masses on the South Brazilian Shelf (27-30 degrees S) and assessed the seasonality of continental runoff on the distribution of shelf water masses. The data were obtained from water and sediment samples collected in the austral winter of 2003 and austral summer of 2004 in three transects. The terrestrial nutrient input was significantly reduced at stations away from the coast, but high values of nutrients were maintained in subsurface waters due the presence of South Atlantic Central Water (SACW) at greater depths. At shallow sampling stations the influence of freshwater runoff was related to (1) the dominance of calcareous benthic Foraminifera, such as lagoon-related Pseudononion atlanticum, Hanzawaia boueana, Bulimina marginata, Bolivina striatula, Elphidium poeyanum, together with several agglutinated species, including Arenoparrella mexicana, Gaudryina exilis, and Trochammina spp., common in coastal environments subject to wide salinity fluctuations. In contrast, smaller forms and higher species diversity characterized the assemblage at offshore stations. In winter, the presence of Buccella peruviana and Uvigerina peregrina at Santa Marta Cape suggest the possible transport of those species of Subantarctic Shelf Waters (SASW) origin. Foraminifera associated to Subtropical Shelf Water (STSW) were dominated by Globocassidulina subglobosa in both seasons. In summer, the occurrence of U. peregrina in the shallower stations suggested the influence of SACW nutrients brought up by upwelling of deeper waters. (C) 2008 Elsevier Ltd. All rights reserved.