Iberian Peninsula Coast Research Articles

Population genetic structure of the prosobranch Nassarius reticulatus (L.) in a ria seascape (NW Iberian Peninsula) as revealed by RAPD analysis

Randomly amplified polymorphic DNA (RAPD) banding patterns were compared between samples of the netted dogwhelk Nassarius reticulatus from 11 locations along the NW Iberian Peninsula coast. To detect if rias (estuaries formed by drowned river valleys) might promote genetic differentiation, five sampling sites were located within a ria (ria of Muros) and the remaining six were scattered along open-coast areas at increasing distances from the ria mouth. Population differentiation statistics (Φ-values) were estimated using a hierarchical analysis of molecular variance (AMOVA) with samples sorted into two groups: open-coast and ria populations. Despite a high potential to disperse, AMOVA demonstrated a modest, statistically significant genetic heterogeneity among N. reticulatus populations. Most of the genetic structure resided in differences among open-coast populations; ria populations were genetically homogeneous. No obvious geographical pattern was detected for the pairwise genetic distances (non-metric multidimensional scaling; UPGMA tree; Mantel test). Unlike previous studies with other species at a variety of estuarine systems other than rias, there was no evidence that the ria of Muros may enhance the genetic divergence of N. reticulatus populations. This discrepancy is discussed in relation to the biological features of the species (high dispersal potential and a preference for mid-low estuarine habitat) and the strong hydrographic connectivity between ria and neighbouring off-shore waters.

Population structure of Merluccius merluccius along the Iberian Peninsula coast

AbstractPrespawning hake caught in eight locations around the Iberian Peninsula were genetically analysed. The distribution of variation at five microsatellite loci suggests that the species follows a population model of isolation by distance in this geographical area. Three different areas can be identified: the Mediterranean Sea, the Portuguese coast, and the Cantabric Sea. The lack of differentiation between samples caught in the VIIIa,b,d and in the VIIIc ICES Areas suggests that, based on genetic information, the boundary between northern and southern stocks of European hake should be reconsidered.

Grateloupia lanceola versus Grateloupia turuturu (Gigartinales, Rhodophyta): en la Península Ibérica

Grateloupia lanceola was originally described from the southern Iberian Peninsula and northwestern Africa coasts. Its current Iberian distribution only includes some localities in NW (La Coruna) and SE (Malaga) Spain. The closely related invasive species Grateloupia turuturu is present in Galicia (NW Spain) since 1991 and in northern Portugal since 1997. Galicia is the only area in Europe where both especies are sympatric. This paper presents a comparative study of G. lanceola and G. turuturu along the Iberian Peninsula coast. The blade of G. lanceola is purplish red with a characteristic emerald green colour to the base, and usually has scattered paler spots. Moreover, it is 200-450 µm thick, has a sort stipe, and marginal proliferations developed usually only in eroded areas. The lamina of G. turuturu is red or pink through, without paler spots or green areas. It is thinner (130-250 µm), has a long stipe, and frequent congenital marginal proliferations.

New study of the 1755 earthquake source based on multi-channel seismic survey data and tsunami modeling

Abstract. In the last years, large effort has been done to carry out multi-channel seismic reflection surveys (MCS) in SW Iberia to locate the active tectonic structures that could be related to the generation of the 1755 Lisbon earthquake and the tsunami. The outcome of these researches led to the identification of a large, compressive tectonic structure, named Marques de Pombal thrust that, alone can account for only half the seismic energy released by the 1755 event. However, these investigations have shown the presence of additional tectonic structures active along the continental margin of SW Iberia that are here evaluated to model the tsunami waves observed along the coasts of Iberia, Morocco and Central Atlantic. In this paper we present a new reappraisal of the 1755 source, proposing a possible composite source, including the Marques de Pombal thrust fault and the Guadalquivir Bank. The test of the source is achieved through numerical modelling of the tsunami all over the North Atlantic area. The results presented now incorporate data from the geophysical cruises and the historical observation along the European coasts and also from the Western Indies. The results of this study will, hopefully, improve the seismic risk assessment and evaluation in the Portuguese territory, Spain, Morocco and Central/North Atlantic.

Long-term (1977–1997) measurements of carbon dioxide in the Eastern North Atlantic: evaluation of anthropogenic input

From 1977to 1997CO parameters were measured in the Eastern North Atlantic Ocean. A data set of 12 cruises carried out between 373N and 473N, 203W and the Iberian Peninsula coast, were used to estimate the anthropogenic carbon (C ) based on a back-calculation technique, with the aim of evaluating its temporal evolution in that 20-year period. The rate of change of the integrated C down to 2000 m was 0.95 mol m yr. Half of this input corresponds to a direct uptake of atmospheric CO (0.48 mol m yr), while the other half enters by advection. The C advected by the Mediterranean Water (MW) is the most important contributor to the total C advected into the area, representing 59% (0.27$0.09 mol m yr), whereas the Labrador Sea Water contributes only 15% (0.07$0.04 mol m yr). The particular formation mechanism of MW explains its high content of advected C . When MW is formed in the Gulf of CaH diz, 85% of Central Water is entrained by sinking of the Mediterranean Over#ow Water. Central Waters have about 50mol kg of C ; thus this entrainment represents 0.07GtC yr, which is about 26% of the C transported by the thermohaline circulation in the North Atlantic. 2001 Elsevier Science Ltd. All rights reserved.

The benthic Gammaridea (Crustacea, Amphipoda) fauna of Algeciras Bay (Strait of Gibraltar): distributional ecology and some biogeographical considerations

The Gammaridea fauna of Algeciras Bay, located on the Mediterranean side of the Strait of Gibraltar, was studied with regard to the species composition, distribution and ecology. Of the 116 species identified, 13 are recorded for the first time along the Iberian Peninsula coast, 30 for the Spanish coast and 78 for the Andalusian coast. Two species, Apherusa bispinosa (Bate 1857) and Idunella nana (Schiecke 1973), were collected for the second time in the Mediterranean Sea; this represents the first record of I. nana since its original description. The abundances of the various species and their distribution in terms of bathymetry and type of substrate were analysed, as was the enlargement of the distributional range of some species in the Mediterranean Sea. With regard to biogeographical distribution, Algeciras Bay can be considered a typical Mediterranean locality despite being situated in the Strait of Gibraltar. This is in agreement with previous studies on the amphipod fauna of the Portuguese coast.

Distribution pattern of decapod larvae off the north-western Iberian Peninsula coast (NE Atlantic)

In October 1977 the model of general circulation of the water masses off the coast of Galicia, and the presence of a coastal upwelling, led to a high primary productivity. This high productivity in rum favoured the development of a rich population of decapod larvae. The abundance and distribution pattern of these organisms were closely linked (I) to the abundant presence of the corresponding adult species in the area, (li) with the spatial distribution of phytoplanlctonic populations concurrently studied by Estrada (/. Plankton Res., 6, 417-434 (1984)) and (iu) with the hydrodynamic pattern in the area. Fifty-two decapod larvae taxa were identified and Solenocera membranacea, Pisidia longicornis, Pdumnus hirtellus and Goneplax rhomboidcs were the most representative species It was observed that the greatest concentrations of larvae (3387 larvae 10~2 m~3) were to be found near the mouth of the Rfas Baixas (situated in the south-west of the coastal area) and in some zones further out to sea (863 larvae 102 m3) (due to a process of hydrodynamic transport)

Spatio-temporal changes (1956-2013) of coastal ecosystems in Southern Iberian Peninsula (Spain)

Spatial and temporal changes of coastal vegetation since the 1950s along the southern Iberian Peninsula coast (Andalusia, Spain), have been analysed. Three examples have been selected: one on the Atlantic coast (Punta Umbria, Huelva) and two in the Mediterranean: Marbella (Malaga) and Punta Entinas-Sabinar (Almeria). The three areas are currently included in the Andalusian Network of Protected Natural Areas (RENPA). Aerial photographs dated in the years 1956-57 have been used and compared with the most recent (2013) using photointerpretation techniques and GIS (geographic information system) software. Observations have been completed with phytosociological data and historical cartography (forest and vegetation maps) that allowed us to analyse and identify the different communities and their transformation over 60 years. The results show the changes and impacts linked to the anthropic actions in this territory. In recent decades, the reforestation and expansion of urbanized areas are the main cause of coastal ecosystem alteration, especially affecting the Marbella coast that has had its dune system considerably reduced.