35 results found in 4 ms Page 1 of 4
Using remote sensing as a support to the implementation of the European Marine Strategy Framework Directive in SW Portugal
Created: 2017-05-04 10:37:53.262 by: Generation Service
The exclusive economic zones (EEZ) of coastal countries are coming under increasing pressure from various economic sectors such as fishing, aquaculture, shipping and energy production. In Europe, there is a policy to expand the maritime economic sector without damaging the environment by ensuring that these activities comply with legally binding Directives, such as the Marine Strategy Framework Directive (MSFD). However, monitoring an extensive maritime area is a logistical and economic challenge. Remote sensing is considered one of the most cost effective, methods for providing the spatial and temporal environmental data that will be necessary for the effective implementation of the MSFD. However, there is still a concern about the uncertainties associated with remote sensed products. This study has tested how a specific satellite product can contribute to the monitoring of a MSFD Descriptor for \"good environmental status\" (GES). The results show that the quality of the remote sensing product Algal Pigment Index 1 (API 1) from the MEdium Resolution Imaging Spectrometer (MERIS) sensor of the European Space Agency for ocean colour products can be effectively validated with in situ data from three stations off the SW Iberian Peninsula. The validation results show good agreement between the MERIS API 1 and the in situ data for the two more offshore stations, with a higher coefficient of determination (R-2) of 0.79, and with lower uncertainties for the average relative percentage difference (RPD) of 24.6% and 27.9% and a root mean square error (RMSE) of 0.40 and 0.38 for Stations B and C, respectively. Near to the coast, Station A has the lowest R-2 of 0.63 and the highest uncertainties with an RPD of 112.9% and a RMSE of 1.00. It is also the station most affected by adjacency effects from the land: when the Improved Contrast between Ocean and Land processor (ICOL) is applied the R-2 increases to 0.77 and there is a 30% reduction in the uncertainties estimated by RPD. The MERIS API 1 product decreases from inshore to offshore, with higher values occurring mainly between early spring and the end of the summer, and with lower values during winter. By using the satellite images for API 1, it is possible to detect and track the development of algal blooms in coastal and marine waters, demonstrating the usefulness of remote sensing for supporting the implementation of the MSFD with respect to Descriptor 5: Eutrophication. It is probable that remote sensing will also prove to be useful for monitoring other Descriptors of the MSFD. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
Organizations: European Space Agency
Created: 2017-05-04 10:46:48.261 by: Generation Service
The demand for marine sand in the Netherlands as well as globally is increasing. Over the last decades, only shallow sand extraction of 2 m below the seabed was allowed on the Dutch Continental Shelf (DCS). To guarantee sufficient supply and to decrease the surface area of direct impact, the Dutch authorities started to promote sand extraction depths over 2 m for sand volumes over 10 million m(3). The ecological effects of deep sand extraction, however, are still largely unknown. Therefore, we investigated short-term effects (0-2.5 y) of deep sand extraction (20-24 m) and compared these with other case studies such as, regular shallow sand extraction on the DCS (2 m) and an 8 m deepened shipping lane. For intercomparison between case studies we used tide-averaged bed shear stress as a generic proxy for environmental and related ecological effects. Bed shear stress can be estimated with a two-dimensional quadratic friction law and showed a decrease from 0.50 to 0.04 N m(-2) in a borrow pit in 20 m deep water and extraction depths up to 24m. Macrozoobenthos in a borrow pit with a tide-averaged bed shear stress of around 0.41 N m(-2) is expected to return back to pre-extraction conditions within 4-6 year. When tide-averaged bed shear stress decreases below 0.17 N m(-2) enhanced macrozoobenthic species richness and biomass can occur. Below a tide-averaged bed shear stress of 0.08 N m(-2), increasing abundance and biomass of brittle stars, white furrow shell (Abra alba) and plaice (platessa platessa) can be expected. Below 0.04 N m(-2), an overdominance and high biomass of brittle stars can be expected whereas demersal fish biomass and species composition may return to reference conditions. Next to changes in faunal composition, a high sedimentation rate can be expected. Ecological data and bed shear stress values were transformed into ecosystem-based design (EBD) rules. At higher flow velocities and larger water depths, larger extraction depths can be applied to achieve desired tide-averaged bed shear stresses for related ecological effects. The EBD rules can be used in the early-design phases of future borrow pits in order to simultaneously maximise sand yields and decrease the surface area of direct impact. The EBD rules and ecological landscaping can also help in implementing the European Union's Marine Strategy Framework Directive (MSFD) guidelines and moving to or maintaining Good Environmental Status (GES). (C) 2015 Elsevier B.V. All rights reserved.
Places: Dutch Continental Shelf
Organizations: European Union
Created: 2017-05-04 10:27:43.056 by: Generation Service
This work aimed to show that the sea bed of two environmentally-different regions of the North Sea varies both spatially and temporally with respect to their biological communities and bioturbation characteristics. The two contrasting sites studied were north of the Dogger Bank (ND) (85 m) and the Oyster Grounds (OG) (45 m). The physical environment varied between and within sites, mainly influenced by sediment chlorophyll a content and water temperature. Our data revealed that the depth of the apparent Redox Potential Discontinuity (aRPD) layer at OG varied between 2.2 cm in February and 6.5 cm in October; evidence of bioturbation activity (e.g., feeding voids) was observed within the sediment profile. In contrast, at the ND site the aRPD values ranged from 1.7 cm in February to 2.5 cm in May and feeding voids and infaunal burrows were restricted to sediment depths far shallower than those observed at OG. Communities at ND were dominated by a number of surficial-sediment dwelling polychaete species (e.g., Notomastus latericeus, capitellids) while those of OG were dominated by the brittlestar Amphiura filiformis, together with significant numbers of deeper-dwelling taxa such as the ghost shrimp Callianassa subterranea and the bivalve mollusc Corbula gibba. Our data imply that regions of the North Sea which experience dissimilar environmental conditions not only possess different infaunal communities but also contrasting seasonal fluctuations and bioturbation capacities. The ecological implications of these findings, including inferences for carbon and nutrient cycling, are discussed in relation to the wider North Sea ecosystem.
Places: Oyster Grounds
Organizations: Dogger Bank
Created: 2017-07-20 08:34:26.326 by: Ciro Manzo
final version of VPR for Modis data
People: Sergio Pugnaghi
Organizations: European Geosciences Union
Created: 2018-02-15 10:38:34.713 by: Raul Palma
Ground deformation mapping is a typical use case for this VRC. It may be carried out by different researchers on different volcanoes or even on the same volcano
Expressions: load ground velocity file InSAR velocity input data ground velocity file in raster format ground velocity file GPS site velocity
Reference: Fernandes H.M.-Cultural impact on the geochemistry of sediments in Jacarepaguá lagoon, Rio de Janeiro, Brazil
Created: 2018-08-01 15:08:31.561 by: Generation Service
Paper abstract:This paper addresses the heavy metal pollution development in Jacarepaguá coastal lagoon, by means of sediment core analysis.
Reference: Perez-Ruzafa A.-Environmental and biological changes related to recent human activities in the Mar Menor (SE of Spain)
Created: 2018-08-01 14:58:35.456 by: Generation Service
Paper abstract:In this article are studied the effects of recent human activities in the Mar Menor, including enlargement of a channel of communication with the open sea and dredging and deposition of sand to make beaches.
Reference: Schmidt S.-Bioturbation at the water-sediment interface of the Thau Lagoon: impact of shellfish farming
Created: 2018-08-01 15:10:58.618 by: Generation Service
Paper abstract:Quantifying of sediment reworking processes provides new insights into benthic ecosystem functioning of the Thau lagoon, an important European shellfish farming area. In order to evaluate bioturbation rates of surface sediments, profiles of 7Be and 234Th were measured in cores collected since December 2001 to December 2006. Surface sediment mixing of the Thau lagoon is primarily controlled by the quality of particle input, i.e. the food supply to the benthic fauna, mainly governed by the hydrological and seasonal conditions. But locally shellfish production is a key parameter that influences bioturbation through biodeposition.
Reference: Maanan M.-A long-term record of land use change impacts on sediments in Oualidia lagoon, Morocco
Created: 2018-08-01 15:16:30.782 by: Generation Service
Paper abstract:An integrated approach, involving land use patterns and heavy metal contents of the surficial and cored sediment, was proposed to detect the characteristic spatial and temporal scale of point and non-point source human disturbances on the Oualidia lagoon in Morocco. Land-use types affected lagoon sediment pollution in different ways: 1) agricultural areas had the highest potential for sediment contamination by heavy metals, particularly Pb, Cu and Hg, 2) Ni and Cr are the main pollutants originating from urban sewage and 3) oyster farming and traditional land uses such as salt flats, pastures showed low levels of others metals.
Reference: Guerra R.-Impacts of maintenance channel dredging in a northern Adriatic coastal lagoon. I: Effects on sediment properties, contamination and toxicity
Created: 2018-08-01 15:03:02.281 by: Generation Service
Paper abstract:The aim of the present study was to assess the environmental effects of channel dredging, carried out in Pialassa Baiona between October 2004 and August 2005, combining an integrated method to evaluate sediment quality with an experimental design based on Beyond BACI principles. The present paper focuses on the effects on sediment properties, contamination, and toxicity.
Places: Adriatic Sea
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