Ceramium Roth (Ceramiales, Rhodophyta) from Venice lagoon (Adriatic Sea, Italy): Comparative studies of Mediterranean and Atlantic taxa

The cosmopolitan genus Ceramium (Ceramiaceae, Rhodophyta) is a large and systematically complex group. The taxonomy of this genus remains in a chaotic state due to the high degree of morphological variation. Culture studies, suggesting a strong influence of environment on phenotype, and the use of molecular tools have recently questioned the validity of morphological features used in species recognition. Here we compare three Ceramium taxa from Venice lagoon with samples from northwest Europe using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) and the rbcL-rbcS intergenic spacer combined with morphological observations. A strongly banded species, previously identified as member of a poorly understood and misnamed group, the Ceramium diaphanum complex sensu Feldmann-Mazoyer, is probably conspecific with British samples of Ceramium diaphanum sensu Harvey, for which no valid name has been identified up to now. We show that Ceramium polyceras (Kutzing) Zanardini is a valid name for this species. A fully corticated Ceramium species morphologically resembling C. secundatum differs at the species level from Atlantic C. secundatum; a valid name for this entity is Ceramium derbesii Solier ex Kutzing, described from Mediterranean France. A third species characterized by cortical spines, previously listed as Ceramium ciliation var. robustum (J. Agardh) Mazoyer, is shown to be Ceramium nudiusculum (Kutzing) Rabenhorst, originally described from Venice.

High-resolution seismic reflection investigation of gas accumulation and seepage in the tidal channels of the Ria of Aveiro barrier lagoon (Portugal)

O metano é um gás de estufa potente e uma importante fonte de energia. A importância global e impacto em zonas costeiras de acumulações e escape de gás metano são ainda pouco conhecidas. Esta tese investiga acumulações e escape de gás em canais de maré da Ria de Aveiro com dados de cinco campanhas de reflexão sísmica de alta resolução realizadas em 1986, 1999, 2002 e 2003. Estas incluem três campanhas de Chirp (RIAV99, RIAV02 e RIAV02A) e duas campanhas de Boomer (VOUGA86 e RIAV03). O processamento dos dados de navegação incluíram filtros de erros, correcções de sincronização de relógios de sistemas de aquisição de dados, ajuste de “layback” e estimativa da posição de “midpoint”. O processamento do sinal sísmico consistiu na correcção das amplitudes, remoção de ruído do tipo “burst”, correcções estáticas, correcção do “normal move-out”, filtragem passabanda, desconvolução da assinatura e migração Stolt F-K. A análise da regularidade do trajecto de navegação, dos desfasamentos entre horizontes e dos modelos de superfícies foi utilizada para controlo de qualidade, e permitiu a revisão e melhoria dos parâmetros de processamento. A heterogeneidade da cobertura sísmica, da qualidade do sinal, da penetração e da resolução, no seu conjunto constrangeram o uso dos dados a interpretações detalhadas, mas locais, de objectos geológicos da Ria. É apresentado um procedimento para determinar a escolha de escalas adequadas para modelar os objectos geológicos, baseado na resolução sísmica, erros de posicionamento conhecidos e desfasamentos médios entre horizontes. As evidências de acumulação e escape de gás na Ria de Aveiro incluem turbidez acústica, reflexões reforçadas, cortinas acústicas, domas, “pockmarks” e alinhamentos de “pockmarks” enterradas, horizontes perturbados e plumas acústicas na coluna de água (flares). A estratigrafia e a estrutura geológica controlam a distribuição e extensão das acumulações e escape de gás. Ainda assim, nestes sistemas de baixa profundidade de água, as variações da altura de maré têm um impacto significativo na detecção de gás com métodos acústicos, através de alterações nas amplitudes originais de reflexões reforçadas, turbidez acústica e branqueamento acústico em zonas com gás. Os padrões encontrados confirmam que o escape de bolhas de gás é desencadeado pela descida da maré. Há acumulações de gás em sedimentos Holocénicos e no substrato de argilas e calcários do Mesozóico. Evidências directas de escape de gás em sondagens em zonas vizinhas, mostraram gás essencialmente biogénico. A maioria do gás na área deve ter sido gerado em sedimentos lagunares Holocénicos. No entanto, a localização e geometria de estruturas de escape de fluidos em alguns canais de maré, seguem o padrão de fracturas do substrato Mesozóico, indicando uma possível fonte mais profunda de gás e que estas fracturas funcionam como condutas preferenciais de migração dos fluidos e exercem um controlo estrutural na ocorrência de gás na Ria.

Calibration and validation of hydrodynamic, salt and heat transport models for Ria de Aveiro lagoon (Portugal)

Ria deAveiro is a very complex shallow water coastal lagoon located on the northwest of Portugal. Important issues would be left unanswered without a good understanding of hydrodynamic and transport processes occurring in the lagoon. Calibration and validation of hydrodynamic, salt and heat transport models for Ria de Aveiro lagoon are presented. The calibration of the hydrodynamic model was performed adjusting the bottom friction coefficient, through the comparison between measured and predicted time series of sea surface elevation for 22 stations. Harmonic analysis was performed in order to evaluate the model's accuracy. To validate the hydrodynamic model measured and predicted SSE values were compared for 11 stations, as well as main flow direction velocities for 10 stations. The salt and heat transport models were calibrated comparing measured and predicted time series of salinity and water temperature for 7 stations, and the RMS of the difference between the series was determined. These models were validated comparing the model results with an independent field data set. The hydrodynamic and the salt and heat transport models for Ria de Aveiro were successfully calibrated and validated. They reproduce accurately the barotropic flows and can therefore adequately represent the salt and heat transport and the heat transfer processes occurring in Ria deAveiro.

Lagrangian transport of particles in Ria de Aveiro lagoon, Portugal

A two-dimensional vertically integrated hydrodynamic model coupled to a particle tracking model is applied to study the dispersion processes and residence time in Ria de Aveiro lagoon (Portugal). The only dispersion process that is considered in this study is the advection, according to the main characteristics of the local hydrodynamic. The particle tracking model computes the particles position at each time step, using a fourth-order Runge-Kutta integration method. The dispersion of passive particles released along the lagoon and in critical areas are studied in this work. The residence time is also determined for the entire lagoon. The results show that the mixture between particles coming from different channels of the lagoon is negligible in a time scale higher than 2 tidal cycles. The residence time for the lagoon central area is about 2 days, revealing a strong marine influence in this area. At the upper reaches of the channels were found values higher than 2 weeks.

Biology, ecology, population dynamics and distribution of metals in Sepia officinalis on a typical estuarine coastal lagoon - Ria de Aveiro

The common cuttlefish, Sepia officinalis, is a necto-benthic cephalopod that can live in coastal ecosystems, with high influence of anthropogenic pressures and thus be vulnerable to exposure to various types of contaminants. The cuttlefish is a species of great importance to the local economy of Aveiro, considering the global data of catches of this species in the Ria de Aveiro. However, studies on this species in Ria de Aveiro are scarce, so the present study aims to fill this information gap about the cuttlefish in the Ria de Aveiro. The cuttlefish enters Ria de Aveiro in the spring and summer to reproduce, returning to deeper waters in the winter. In terms of abundance, the eastern and center regions of the lagoon, closer to the sea, showed the highest values of abundance, while the northern and southern regions of the main channel had the lowest abundance. This fact may be related to abiotic factors, as well as depth, salinity and temperature. In the most southern point of the Ria de Aveiro (Areão) no cuttlefish was caught. This site had the lowest values of salinity and depth. The cuttlefish has an allometric the females being heavier than males to mantle lengths greater than 82.4 mm. Males reach sexual maturity first than females. In Ria de Aveiro in a generation of parents was found. The cuttlefish, presents itself as opportunistic predators, consuming a wide variety of prey from different taxa. The diet was similar in different sampling locations observing significant differences for the seasons. S. officinalis was captured at 10 sites in the Ria de Aveiro with different anthropogenic sources of contamination. Thus, levels of metals analyzed were similar at all sampling sites, with the exception of a restricted area, Laranjo, which showed higher values. The cuttlefish has the ability to accumulate metals in your body. The levels of Fe, Zn, Cu, Cd, Pb and Hg found in the digestive gland and mantle reflect a differential accumulation of metals in the tissues. This accumulation is related to the type and function of tissue analyzed and the type of metal analysis (essential and non-essential). The metal concentrations in the digestive gland are higher than in the mantle, with the exception of mercury. This may be due to the high affinity of the mantle for the incorporation of methylmercury (MeHg), the most abundant form of mercury. The accumulation of metals can vary over a lifetime, depending on the metal. The concentrations of Zn, Cd and Hg increases throughout life, while Pb decreases and essential metals such as Fe and Cu remain constant. The data collected suggest that the cuttlefish (Sepia officinalis) can be used as a bioindicator of environmental contamination for some metals.

Hydrodynamic model intercomparison for the patos lagoon (Brazil)

An intercomparison study is carried out between two models with different formulations and spatial discretizations in order to overcome the limitations posed by the standard calibration and validation procedures and improve confidence in the hydrodynamic results for the Patos Lagoon. Numerical simulations were carried out applying the TELEMAC and MOHID models, based on the same boundary conditions and identical calibration coefficients so differences in calculated flow conditions result from the formulations and parameterizations of each model. Results from both models are compared with measurements from three stations inside the lagoon. Preliminary results indicate that both models compare well with the measurements and with each other. These results increase the confidence on hydrodynamic results for the Patos Lagoon and provide the first step towards water quality studies for the area.

The LOICZ biogeochemical budget approach applied to Ria Formosa lagoon, - Algarve, South Portugal

Dissertação mest., Gestão da Água e da Costa, Universidade do Algarve, 2007

Characterisation of physiological conditions and evaluation of well-being in two species of bivalve molluscs (Ruditapes philippinarum and Chamelea gallina) intensively exploited in coastal and lagoon areas of the Northern Adriatic Sea (Italy)

Tese de Doutoramento, Ecologia, Especialidade de Ecofisiologia, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2007

Comparison of methods of eutrophication assessment in a coastal lagoon (Ria Formosa)

Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

Seawater acidification by CO2 in a coastal lagoon environment: Effects on life history traits of juvenile mussels Mytilus galloprovincialis

The carbonate chemistry of seawater fromthe Ria Formosa lagoon was experimentallymanipulated, by diffusing pure CO2, to attain two reduced pH levels, by−0.3 and−0.6 pH units, relative to unmanipulated seawater. After 84 days of exposure, no differences were detected in terms of growth (somatic or shell) or mortality of juvenile mussels Mytilus galloprovincialis. The naturally elevated total alkalinity of the seawater (≈3550 μmol kg−1) prevented under-saturation of CaCO3, evenunder pCO2 values exceeding 4000 μatm, attenuating the detrimental effects on the carbonate supply-side. Even so, variations in shell weight showed that net calcification was reduced under elevated CO2 and reduced pH, although the magnitude and significance of this effect varied among size-classes. Most of the loss of shell material probably occurred as post-deposition dissolution in the internal aragonitic nacre layer. Our results show that, even when reared under extreme levels of CO2- induced acidification, juvenileM. galloprovincialis can continue to calcify and grow in this coastal lagoon environment. The complex responses of bivalves to ocean acidification suggest a large degree of interspecific and intraspecific variability in their sensitivity to this type of perturbation. Further research is needed to assess the generality of these patterns and to disentangle the relative contributions of acclimation to local variations in seawater chemistry and genetic adaptation.

Effects of environmental conditions on planktonic abundances, benthic recruitment and growth rates of the bivalve mollusc Ruditapes decussatus in a Portuguese coastal lagoon

Controlling environmental parameters for the early stages of marine invertebrates have received little attention, particularly in field studies. This study involves measurement of abundances and growth rates of the bivalve Ruditapes decussatus Linnaeus 1758 during its planktonic larval and early benthic life stages in a coastal lagoon: Ria Formosa, Portugal. Measured abundances were compared with tidal amplitude, water temperature, salinity, wind velocity and direction, and a food availability indicator 2chlorophyll a). Data were obtained on abundance and prodissoconch length of the larvae, measured two tothreetimes perweek,and ofpost-larval stagesindividuals thathadsettled inartificial collectors over10months.Larval and juvenile cohorts were identified using size-frequency distributions and larval ages estimated by larval shell growth lines.

Decapod crustacean larvae dynamics in the west continental coast of Portugal: the region adjacent to Aveiro coastal lagoon as model

Tese de dout., Ciências do Mar, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2010

Ecology of the invertebrate macrofauna of a Ria Formosa lagoon salt marsh

Tese de doutoramento, Ecologia, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2003