No abstract

Heavy metals such as lead, mercury, cadmium, zinc and copper are among the most important pollutants because of their non-biodegradability and toxicity above certain thresholds. Here, we review methods for sensing heavy metal ions (HMI) in water samples using screenprinted electrodes (SPEs) as transducers. The review (with 107 refs.) starts with an introduction into the topic, and this is followed by sections on (a) mercury-coated SPEs, (b) bismuth-coated SPEs, (c) gold-coated SPEs (d) chemically modified and non-modified carbon SPEs, (e) enzyme inhibition-based SPEs, and (f) an overview of commercially available electrochemical portable heavy metal analyzers. The review reveals the significance of SPEs in terms of decentralized and of in situ analysis of heavy metal ions in environmental monitoring.

The European Water Framework Directive (WFD; 2000/60/EG) and the European Marine Strategy Framework Directive (MSFD; 2008/56/EC) were umbrella legislations for fresh and marine waters. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. Both directives have the same concept, comparing the current state of an area with that which would be expected under minimal or sustainable human use of that area and in case of degradation, intervening to bring it back to the desired good status. However, each directive used specific principles to fill it in. For the WFD, this was executed during the last decade, and many results of it were already published. This process delivered valuable knowledge on which the implementation of the MSFD can be founded.Therefore, the ICES Benthos Ecology Working Group aimed to stress and discuss some issues, with focus on benthic macro-invertebrates, related to the fulfillment of the principles of both directives. This through the description of (1) how the principles are theoretically filled in by both directives

Invasive ecosystem engineers (IEE) are potentially one of the most influential types of biological invaders. They are expected to have extensive ecological impacts by altering the physical-chemical structure of ecosystems, thereby changing the rules of existence for a broad range of resident biota. To test the generality of this expectation, we used a global systematic review and meta-analysis to examine IEE effects on the abundance of individual species and communities, biodiversity (using several indices) and ecosystem functions, focusing on marine and estuarine environments. We found that IEE had a significant effect (positive and negative) in most studies testing impacts on individual species, but the overall (cumulative) effect size was small and negative. Many individual studies showed strong IEE effects on community abundance and diversity, but the direction of effects was variable, leading to statistically non-significant overall effects in most categories. In contrast, there was a strong overall effect on most ecosystem functions we examined. IEE negatively affected metabolic functions and primary production, but positively affected nutrient flux, sedimentation and decomposition. We use the results to develop a conceptual model by highlighting pathways whereby IEE impact communities and ecosystem functions, and identify several sources of research bias in the IEE-related invasion literature. Only a few of the studies simultaneously quantified IEE effects on community/diversity and ecosystem functions. Therefore, understanding how IEE may alter biodiversity-ecosystem function relationships should be a primary focus of future studies of invasion biology. Moreover, the clear effects of IEE on ecosystem functions detected in our study suggest that scientists and environmental managers ought to examine how the effects of IEE might be manifested in the services that marine ecosystems provide to humans.

No abstract

Using an indirect and integrated approach, we quantified the magnitude and temporal variabiiity of the contribution of macrozoobenthos to the upward flux of inorganic nitrogen and phosphorus on a sandy tidal flat of the Seto inland Sea, Japan. From Apnl1994 to April 1996, we conducted monthly field surveys on the abundance and faunal composition of the macrozoobenthic communities inhabiting the lower part of the intertidal zone. Subsequently, we carried out 24 h day/night laboratory experiments on the nutrient excretion rate by various size-classes of the dominant species. We then obtained the animal nutrient excretion over a 2 yr period, muitiplying the species-specific excretion rates by the actual animal biomass found on the tidal flat. Additionaliy, for ali different seasons, we calcuiated the upward diffusive flux from the sediments from the vertical profiies of nutrient concentrations in the porewater. On the flat, the bivalves Ruditapes phihppinarum (Veneridae) and Musculista senhousia (Myhhdae) were dominant, making up 86 I 5.6 % when the total biomass exceeded 100 g DW (dry weight) m-'. From our laboratory experiments, the mean (day and night) nutrient excretion rates at 20 to 22OC by the 2 bivalve species were 18.9 p n o l NH4+-N g-' DW h-I, 4.8 pnol (NO3-+ NO2-)-N g-' DW h-' and 3.3 pmol P043--P g-' DW h-I. ln addition, NH4+-N excretion by R. phiiippinarum, but not that by M. senhousia, was significantly higher during the day than during the night. This occurred while the food (Thalassiosua sp.) offered in spikes was rapidly taken up irrespective of the concentration (within a field relevant spring-summer range of 10 to 60 pg T' chl a) andin day/night treatments. The release of nitrogen (N) and the release of phosphorus (P) were highly correlated with each other, for both R. philippinarum and M. senhousia, with a N/P ratio of 7.8 ? 3.0 and 9.9 * 3.5, respectively. In the field, the bivalve excretion rates of nutrients were calculated to be up to 35.2 mmol NH4+-N m-' d-I, 8.8 mrnol (NO3-+ NO2-)-N m-' d-' and 5.8 mmol P O~~--P m-' d-'. These values rank in the upper range of nutrient excretion by intertidal macrozoobenthos and are comparable to those found on dense assemblages (800 to 2000 g ash free DW m-') of the most investigated mussel, Mytzius eduiis. In addition, nutrient fluxes through bivalve excretion varied strongly within a few months, up to 10-fold (R. philippinarum) and 100-fold (M. senhousia) between April 1994 and August 1994, as related to the temporal change of bivalve standing stock. The extent of nutrient regeneration through diffusive flux was comparable to that reported for other intertidal zones of Japan and in the eutrophic Seto Inland Sea, within a range of 0.2 to 1.5 mmol NH4+-N m-' d-' and 0.01 to 0.05 mmol P043--P m-' d-I, thus more than 1 order of magnitude lower than that due to the excretory activity by R. phiiippinarum and M. senhousia. Our resuits indicate that the dominant bivalves, R. phihppinarum and M. senhousia, play a major role in the processes of benthic...

The use of static indicator species, in which species are expected to have a similar sensitivity or tolerance to either natural or human-induced stressors, does not account for possible shifts in tolerance along natural environmental gradients and between biogeographic regions. Their indicative value may therefore be considered at least questionable. In this paper we demonstrate how species responses (i.e. abundance) to changes in sediment grain size and organic matter (OM) alter along a salinity gradient and conclude with a plea for prudency when interpreting static indicator-based quality indices. Six model species (three polychaetes, one amphipod and two bivalves) from the North Sea, Baltic Sea and the Mediterranean Sea region were selected. Our study demonstrated that there were no generic relationships between environment and biota and half of the studied species showed different responses in different seas. Consequently, the following points have to be carefully considered when applying static indicator-based quality indices: (1) species tolerances and preferences may change along environmental gradients and between different biogeographic regions, (2) as environment modifies species autecology, there is a need to adjust indicator species lists along major environmental gradients and (3) there is a risk of including sibling or cryptic species in calculating the index value of a species.

The endemic limpet Patella ferruginea is the most endangered invertebrate in the Mediterranean Sea. Our study examined a population of P. ferruginea in the Marine Protected Area of "Penisola del Sinis -Isola di Mal di Ventre" (western Sardinia, Italy). During the summer 2009, we carried out a systematic census of P. ferruginea along a 8114 m georeferenced perimeter of coast in the "no take-no entry area" to assess its density, spatial distribution, and morphometric characteristics. Our aim was to provide a detailed map of the distribution of P. ferruginea and to investigate the effects of accessibility, wave exposure and slope of the coast on its occurrence. Patella ferruginea showed the lowest mean density ever reported (0.02 ind/m) and a unimodal population structure characterised by fewer females and juveniles. Accessibility had a major negative effect on the occurrence of P. ferruginea. Exposure was also an important factor in influencing its density, size composition and specimen position within the mesolittoral, while the slope had little influence. Morphometric analysis showed the dominance of the Rouxi form, while the Lamarcki form was confined to exposed sites. Our results demonstrate a highly endangered population of P. ferruginea and suggest that human pressure represents the main risk factor.