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Cianca A.,Instituto Canario Of Ciencias Marinas | Godoy J.M.,Instituto Canario Of Ciencias Marinas | Martin J.M.,University of Las Palmas de Gran Canaria | Perez-Marrero J.,Instituto Canario Of Ciencias Marinas | And 3 more authors.
Global Biogeochemical Cycles | Year: 2012

The impact of low-frequency climate modes on the large-scale variability of chlorophyll-a (a proxy for phytoplankton biomass) concentration in the subtropics is little known. Here we examined the concurrent monthly chlorophyll-a and hydrographical records obtained at two subtropical time series stations (Bermuda Atlantic Time series Study, BATS and European Station for Time series in the Ocean Canary Islands, ESTOC) from the beginning of the time series (1989 at BATS and 1994 at ESTOC) to 2003, in order to analyze its seasonal and interannual variability and investigate the potential correlation with large-scale atmospheric oscillations. At BATS, Chl-a variations are mainly caused by differences in the convective mixing and mesoscale phenomena. Variability in winter mixing is a significant factor at ESTOC as exemplified by years with anomalously deep mixed layer depths. An additional nutrient source causing Chl-a variability at this station likely occurs due to nutrient advection driven by the baroclinic flow caused by the Trade Winds during summertime. We found that interannual variability in mean integrated total Chl-a (TChl-a) is significantly correlated with temperature and salinity anomalies at BATS. Chl-a also covaried with changes in temperature although the correlation was not significant at ESTOC. We could not find any direct correlation between TChl-a and NAO at BATS; the correlation improved between TChl-a and NAO +1year but was still insignificant. However, significant correlations were found for ESTOC between TChl-a anomalies and ENSO (El Nio Southern Oscillation) +3years and NAO +1year time lag. Copyright 2012 by the American Geophysical Union.


Grant
Agency: Cordis | Branch: FP7 | Program: CP | Phase: SEC-2007-3.3-02 | Award Amount: 5.47M | Year: 2008

The Autonomous Maritime Surveillance System (AMASS) will be for the observation and security of wide critical maritime areas in order to reduce actual and potential illegal immigration and the trafficking of drugs, weapons and illicit substances. The surveillance system will consist of autonomous, unmanned surveillance buoys with active and passive sensors, the key sensors being un-cooled thermal imagers connected as a network with wideband radio. Further sensors will include hydrophone arrays and possibly other sensors e.g. CCD camera. A sophisticated data fusion process will enable the transmission of relevant information. Alarms from the system will be displayed on a map system in blue border surveillance command centres providing information on location and direction. It will also be possible for the operator to switch directly to a video stream to view the detected image. AMASS will be a capability for integrated blue border surveillance. In order to realise this system a number of advances in the state of the art are required such as the development of stable autonomous maritime platforms and Hot Spot detection in the difficult maritime environment. The consortium includes the European market leader for optronic border surveillance technology, 4 SMEs, 1 University, 3 Institutes (including one charged with the search and rescue control network coordination for the Canary Islands) and one national armed forces responsible for border protection.


Mendonca A.,University of The Azores | Aristegui J.,University of Las Palmas de Gran Canaria | Vilas J.C.,University of Las Palmas de Gran Canaria | Montero M.F.,University of Las Palmas de Gran Canaria | And 3 more authors.
PLoS ONE | Year: 2012

Seamounts are considered to be "hotspots" of marine life but, their role in oceans primary productivity is still under discussion. We have studied the microbial community structure and biomass of the epipelagic zone (0-150 m) at two northeast Atlantic seamounts (Seine and Sedlo) and compared those with the surrounding ocean. Results from two cruises to Sedlo and three to Seine are presented. Main results show large temporal and spatial microbial community variability on both seamounts. Both Seine and Sedlo heterotrophic community (abundance and biomass) dominate during winter and summer months, representing 75% (Sedlo, July) to 86% (Seine, November) of the total plankton biomass. In Seine, during springtime the contribution to total plankton biomass is similar (47% autotrophic and 53% heterotrophic). Both seamounts present an autotrophic community structure dominated by small cells (nano and picophytoplankton). It is also during spring that a relatively important contribution (26%) of large cells to total autotrophic biomass is found. In some cases, a "seamount effect" is observed on Seine and Sedlo microbial community structure and biomass. In Seine this is only observed during spring through enhancement of large autotrophic cells at the summit and seamount stations. In Sedlo, and despite the observed low biomasses, some clear peaks of picoplankton at the summit or at stations within the seamount area are also observed during summer. Our results suggest that the dominance of heterotrophs is presumably related to the trapping effect of organic matter by seamounts. Nevertheless, the complex circulation around both seamounts with the presence of different sources of mesoscale variability (e.g. presence of meddies, intrusion of African upwelling water) may have contributed to the different patterns of distribution, abundances and also changes observed in the microbial community. © 2012 Mendonça et al.


Monzon-Arguello C.,Instituto Canario Of Ciencias Marinas | Monzon-Arguello C.,University of Las Palmas de Gran Canaria | Monzon-Arguello C.,CSIC - Donana Biological Station | Lopez-Jurado L.F.,University of Las Palmas de Gran Canaria | And 5 more authors.
Journal of Biogeography | Year: 2010

Aim: A key life-history component for many animals is the need for movement between different geographical locations at particular times. Green turtle (Chelonia mydas) hatchlings disperse from their natal location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. In this study, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations. In particular we focus on the evidence for transatlantic transport. Location: Atlantic Ocean. Methods: We used mitochondrial DNA (mtDNA) sequences (n = 1567) from foraging groups (n = 8) and nesting populations (n = 12) on both sides of the Atlantic. Genetic data were obtained for Cape Verde juvenile turtles, a foraging group not previously sampled for genetic study. Various statistical methods were used to explore spatial genetics and population genetic structure (e.g. exact tests of differentiation, G. eneland and analysis of molecular variance). Many-to-many mixed stock analysis estimated the connectivity between nesting and foraging groups. Results: Our key new finding is robust evidence for connectivity between a nesting population on the South American coast (25% of the Surinam nesting population are estimated to go to Cape Verde) and a foraging group off the coast of West Africa (38% of Cape Verde juveniles are estimated to originate from Surinam), thus extending the results of previous investigations by confirming that there is substantial transatlantic dispersal in both directions. Lagrangian drifter data demonstrated that transport by drift across the Atlantic within a few years is possible. Main conclusions: Small juvenile green turtles seem capable of dispersing extensively, and can drop out of the pelagic phase on a transatlantic scale (the average distance between natal and foraging locations was 3048 km). Nevertheless, we also find support for the 'closest-to-home' hypothesis in that the degree of contribution from a nesting population to a foraging group is correlated with proximity. Larger-sized turtles appear to feed closer to their natal breeding grounds (the average distance was 1133 km), indicating that those that have been initially transported to far-flung foraging grounds may still be able to move nearer to home as they grow larger. © 2010 Blackwell Publishing Ltd.


Garcia-Sanz T.,University of Barcelona | Ruiz J.M.,Spanish Institute of Oceanography | Perez M.,University of Barcelona | Ruiz M.,Instituto Canario Of Ciencias Marinas
Estuarine, Coastal and Shelf Science | Year: 2011

In this study, the dispersal of wastes from offshore fish farms was evaluated by analyzing nitrogen stable isotope ratios (δ15N) in macroalgae incubated in the water column at sites located at an increasing distance from the fish cages. Bioassays were performed at three fish farms situated in separate localities with different nutritional conditions (Canary Islands, Murcia and Catalonia) and varying in size, species of fish reared and annual production. Macroalgal bioassays were carried out in two different directions (DI and DII) and they were replicated at each distance in order to evaluate the effect of small-scale variability on the spatial extent of fish farm wastes. The results obtained with δ15N contribute to a better understanding of the application of nitrogen stable isotopes ratios in macroalgae as an effective bioindicator for tracing the dispersion of offshore fish farm wastes, and demonstrate that fish farm wastes can be traced even over distances of some km from the pollution source. In the Canary Islands, the maximum distance obtained for detection of fish farm wastes was between 450 and 700 m. Of the three installations studied, Murcia presented the greatest distance for detection of fish farm waste influence, ranging from between 1550 and 2450 m, whilst in Catalonia this distance was less than 120 m. In Catalonia, the results were masked by the influence of other sources of nitrogen, and thus fish farm wastes were detected at more reduced distances than expected. These results confirm that fish farm wastes can be traced using the nitrogen stable isotope ratios of macroalgae and that this method can also be useful for identifying areas of potential risk to some sensitive ecosystems, and as an early signal that changes in the community structure might occur. © 2010 Elsevier Ltd.

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