Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1–5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic.

Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic. | info:eu-repo/semantics/publishedVersion

An in situ particle imaging system for measurement of high concentrations of suspended particles ranging from 30μm to several mm in diameter, is presented. The system obtains quasi-silhouettes of particles suspended within an open-path sample volume of up to 5cm in length. Benchmarking against spherical standards and the LISST-100 show good agreement, providing confidence in measurements from the system when extending beyond the size, concentration and particle classification capabilities of the LISST-100. Particle-specific transmittance is used to classify particle type, independent of size and shape. This is applied to mixtures of oil droplets, gas bubbles and oil-coated gas bubbles, to provide independent measures of oil and gas size distributions, concentrations, and oil-gas ratios during simulated subsea releases. The system is also applied to in situ measurements of high concentrations of large mineral flocs surrounding a submarine mine tailings placement within a Norwegian Fjord.

An in situ particle imaging system for measurement of high concentrations of suspended particles ranging from 30 μm to several mm in diameter, is presented. The system obtains quasi-silhouettes of particles suspended within an open-path sample volume of up to 5 cm in length. Benchmarking against spherical standards and the LISST-100 show good agreement, providing confidence in measurements from the system when extending beyond the size, concentration and particle classification capabilities of the LISST-100. Particle-specific transmittance is used to classify particle type, independent of size and shape. This is applied to mixtures of oil droplets, gas bubbles and oil-coated gas bubbles, to provide independent measures of oil and gas size distributions, concentrations, and oil-gas ratios during simulated subsea releases. The system is also applied to in situ measurements of high concentrations of large mineral flocs surrounding a submarine mine tailings placement within a Norwegian Fjord. | publishedVersion

A conceptual model was constructed for the functioning the algae-dominated rocky reef ecosystem of the Mediterranean Sea. The Ecosystem-Based Quality Index (reef-EBQI) is based upon this model. This index meets the objectives of the EU Marine Strategy Framework Directive. It is based upon (i) the weighting of each compartment, according to its importance in the functioning of the ecosystem; (ii) biological parameters assessing the state of each compartment; (iii) the aggregation of these parameters, assessing the quality of the ecosystem functioning, for each site; (iv) and a Confidence Index measuring the reliability of the index, for each site. The reef-EBQI was used at 40 sites in the northwestern Mediterranean. It constitutes an efficient tool, because it is based upon a wide set of functional compartments, rather than upon just a few species; it is easy and inexpensive to implement, robust and not redundant with regard to already existing indices.

International audience | A conceptual model was constructed for the functioning the algae-dominated rocky reef ecosystem of the Med-iterranean Sea. The Ecosystem-Based Quality Index (reef-EBQI) is based upon this model. This index meets the objectives of the EU Marine Strategy Framework Directive. It is based upon (i) the weighting of each compartment , according to its importance in the functioning of the ecosystem; (ii) biological parameters assessing the state of each compartment; (iii) the aggregation of these parameters, assessing the quality of the ecosystem functioning , for each site; (iv) and a Confidence Index measuring the reliability of the index, for each site. The reef-EBQI was used at 40 sites in the northwestern Mediterranean. It constitutes an efficient tool, because it is based upon a wide set of functional compartments, rather than upon just a few species; it is easy and inexpensive to implement, robust and not redundant with regard to already existing indices.

Occurrence of algal blooms in coastal waters is predicted to be more prevalent in future. To minimize their occurrence, manipulating the grazing pressure by suspension feeders is a potential management strategy, but its effectiveness may depend on their feeding preference. Therefore, we assessed the clearance rate of a widespread serpulid polychaete Hydroides elegans in larval and adult stages on various coastal phytoplankton. Additionally, the growth and development of H. elegans after consuming these phytoplankton were determined to reflect its sustainability to counter algal blooms. Results showed that H. elegans can consume and utilize different phytoplankton, except diatom Thalassiosira pseudonana, for growth and development in both life stages. Given the fast-colonizing ability which allows easy manipulation of abundance, H. elegans is considered practically and biologically ideal for tackling algal blooms. Other suspension feeders with different feeding niches could be used in combination to maximize the versatility of the top-down control.

Occurrence of algal blooms in coastal waters is predicted to be more prevalent in future. To minimize their occurrence, manipulating the grazing pressure by suspension feeders is a potential management strategy, but its effectiveness may depend on their feeding preference. Therefore, we assessed the clearance rate of a widespread serpulid polychaete Hydroides elegans in larval and adult stages on various coastal phytoplankton. Additionally, the growth and development of H. elegans after consuming these phytoplankton were determined to reflect its sustainability to counter algal blooms. Results showed that H. elegans can consume and utilize different phytoplankton, except diatom Thalassiosira pseudonana, for growth and development in both life stages. Given the fast-colonizing ability which allows easy manipulation of abundance, H. elegans is considered practically and biologically ideal for tackling algal blooms. Other suspension feeders with different feeding niches could be used in combination to maximize the versatility of the top-down control. | Jonathan Y.S. Leung, Napo K.M. Cheung