Systematics and evolution of coastal and deepwater Hydrozoa from the NE Atlantic

The study of the Portuguese Hydrozoa fauna has been abandoned for more than half a century, except for the Azores archipelago. One of the main aims of this Ph.D. project was to contribute new hydrozoan records leading to a more accurate perception of the actual hydrozoan diversity found in Portuguese waters, including the archipelagos of Azores and Madeira, and neighbouring geographical areas, for habitats ranging from the deep sea to the intertidal. Shallow water hydroids from several Portuguese marine regions (including the Gorringe Bank) were sampled by scuba-diving. Deep-water hydroids, from the Azores, Madeira, Gulf of Cadiz and Alboran Sea, were collected by researchers of different institutions during several oceanographic campaigns. Occasional hydroid sampling by scuba-diving was performed in the UK, Malta and Spain. Over 300 hydroid species were identified and about 600 sequences of the hydrozoan ‘DNA barcode’ 16S mRNA were generated. The families Sertulariidae, Plumulariidae, Lafoeidae, Hebellidae, Aglaopheniidae, Campanulinidae, Halopterididae, Kirchenpaueriidae, Haleciidae and Eudendriidae, were studied in greater detail. About 350 16S sequences were generated for these taxa, allowing phylogenetic, phylogeographic and evolutionary inferences, and also more accurate taxonomic identifications. Phylogenetic analyses integrated molecular and morphological characters. Subsequent results revealed: particularly high levels of cryptic biodiversity, polyphyly in many taxonomic groups, pairs of species that were synonymous, the identity of several varieties as valid species, and highlighted phylogeographic associations of hydroids in deep and shallow-water areas of the NE Atlantic and W Mediterranean. It was proved that many (but not all) marine hydroid species with supposedly widespread vertical and/or horizontal geographical distributions, correspond in fact to complexes of cryptic taxa. This study further revealed that, in the NE Atlantic, shallow environments sustain higher hydrozoan diversity and abundance, but the importance of bathyal habitats as a source of phylogenetic diversity was also revealed. The Azorean seamounts were shown to be particularly important in the segregation of populations of hydroids with reduced dispersive potential. The bathyal habitats of the Gulf of Cadiz proved to harbour a considerably high number of cryptic species, which may mainly be a consequence of habitat heterogeneity and convergence of various water masses in the Gulf. The main causes proposed for speciation and population divergence of hydroids were: species population size, dispersal mechanisms and plasticity to inhabit different environmental conditions, but also the influence of oceanic currents (and its properties), habitat heterogeneity, climate change and continental drift. Higher phylogenetic resolution obtained for the family Plumulariidae revealed particularly that glacial cycles likely facilitated population divergence, ultimately speciation, and also faunal evolutionary transitions from deep to shallow waters.

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.