Toxic microalgae and global change : why have proliferations increased along the Mediterranean coast?

The ocean and the continent converge in a very narrow line that is, nonetheless, truly relevant to the health, leisure, and economy of our society. The Mediterranean coastline has undergone major changes over the last fifty years, which is evident in the alteration of its microalgae species. The proliferation of dinoflagellates is now common in microscopic organism communities in this ecosystem as a result of the modifications caused by humans and climate change. The increased frequency with which toxic microalgae blooms are detected has been key to raising awareness of this change

Production-consumption budget in an estuarine bay: How anoxia is prevented in a forced system

Althought the generation of anoxic situations is a well known fact in estuarine bays, in the southem embayment of the Ebro delta (NW Mediterranean), the Alfacs Bay, oxygen depletion is a rare event. In this paper we examine the processes preventing anoxia in the system through a consumption/production budget. From caJculations based upon annual mean values, we conclude that the bay is slightly heterotrophic, that is, that total consumption exceeds autochtonous production by only 1 0%. But heterogeneity in both space and time results in a high variance around the mean used in our budget. We have exarnined the main components of this variance (stratification of the water column, horizontal heterogeneity, phytoplankton production in pulses, etc.) and sorne of them have been incorporated in a simple box-flux model. From this model, we conclude that only the deep water layer is strongly heterotrophic and that its sources of oxygen are vertical rnixing and renovation (50%), diapycnal eddy diffusion (25%) and local production (25%). The generation of anoxia must be driven by the co-occurrence of events associated with oxygen depletion and/or limitation of oxygen transport (i.e., calm weather period after a phytoplankton pulse; lack of estuarine circulation during a long calm weather period, etc.), what we call the covariance between processes. Such covariance is in general low, and in consequence anoxia must be considered a low probability event. Comparing Alfacs Bay with other estuaries in the framework of the proposed conceptual model, three features emerge that may be relevant in order to prevent anoxia: low organic loading (produced plus imported); active estuarine circulation forced by high wind frequency; degradation of the organic matter mainly by benthic consumers

Land Uses Simplified Index (LUSI): Determining Land Pressures and Their Link With Coastal Eutrophication

Human activities on land result in the high-level production of nutrients. When these nutrients reach coastal waters, they could drive the eutrophication process. Here we present the Land Uses Simplified Index (LUSI), an easy-to-use tool for assessing continental pressures on coastal waters. This assessment is done by indirectly estimating continental nutrient loads and concentrations, and their influence on coastal waters. LUSI is based on systematic information describing both the land uses that influence coastal waters by providing nutrient-rich freshwater inflows (urban, industrial, agricultural, and riverine) and the coastline morphology, which can modify this influence, as it determines the degree of coastal water confinement and therefore the likelihood that these inflows will be diluted. A low LUSI value indicates that coastal waters are not or only slightly influenced by continental pressures and/or that these pressures are diluted. On the contrary, a high LUSI value indicates that coastal waters are strongly influenced by continental pressures and/or that these pressures are not diluted. LUSI fulfills a methodological gap, as a simple method to assess coastal pressures when there is a lack of information. Furthermore, it fulfills the requirement of the Water Framework Directive for a true pressure assessment (i.e., not confounded with impact), which for coastal waters imply using pressure data from land. An additional and important feature of LUSI is that it allows the establishment of pressure-impact relationships with impact indicators, such as those related to the Biological Quality Elements of the above Directive. For example, a relationship based on LUSI, as a proxy of pressure, and on the chlorophyll-a concentration, as a proxy of phytoplanktonic biomass and, thus, of the eutrophication impact. By providing insights into the land uses that trigger eutrophication in coastal waters, LUSI aids in the design of measures aimed at remediating anthropogenic damage caused to the environment

Similarities between summer nearshore and inner-shelf plankton communities in the Mediterranean Sea

55 Conference Estuarine Coastal Sciences Association (ECSA 55), Unbounded boundaries and shifting baselines: Estuaries and coastal seas in a rapidly changing world, 6-9 September 2015, LondonIn what degree nearshore plankton communities constitute an independent and distinct assemblage from shelf assemblages is a challenging question. Obvious physical and chemical differences exist among both systems but, also, important exchange and interdependencies are depicted by physical forcing. Clues to answer this question can be inferred by analyzing the degree of similarity between both systems and their respective biological communities. We analyze similarities between samples collected in nearshore and shelf waters in Palma Bay during a sampling period extending from April to September 2014. Strong differences between plankton structure at both sites are interpreted on the basis of physical and chemical variations at each site and on the degree of exchange induced by coastal currents and thermocline erosionPeer Reviewe

High levels of standardized ileal digestible amino acids improve feed efficiency in slow-growing pigs at late grower-finisher stage

Slow-growing pigs negatively affect production efficiency in conventional pig farms by increasing the occupation time of the facilities and being a limiting factor for the All-In/All-Out swine production systems. This subset of pigs is usually managed with the rest of the pigs, and their nutrient requirements may not be fulfilled. The purpose of the present study was to compare the productive performance of slow- and fast-growing pigs to different standardized ileal digestible (SID) amino acids (AA) dietary levels at late grower-finisher stage. A total of 84 pigs were weighed, tagged, and classified as slow-growing (SG; n = 48; 24.1 ± 1.38 kg) or fast-growing pigs (FG; n = 36; 42.7 ± 1.63 kg) at 11 weeks of age. Pigs were housed in mixed sex pens (n = 8 SG+6 FG/pen) equipped with feeding stations to record daily feed intake per individual pig. Pigs were assigned to three dietary treatments resulting in a 2 × 3 factorial arrangement at 15 weeks of age. Isoenergetic diets were formulated by increasing the ideal protein profile based on the following SID lysine (Lys) levels: 0.92%, 1.18% and 1.45%. Pigs were weighed bi-weekly until 21 weeks of age. Fast-growing pigs were 33.7 kg heavier, gained 255 g/day and consumed 625.5 g/day more than SG pigs (p 0.05). However, feed conversion ratio was 0.3 lower for SG pigs fed 1.45% SID Lys/AA compared to SG pigs fed 0.92% SID Lys/AA (p = 0.002). Feed conversion ratio was not different within the FG pigs' dietary treatments (p > 0.05). The efficiency of SG pigs may be improved when dietary SID AA levels are increased from 0.92 up to 1.45% SID Lys/AA. Thus, nutrient requirements may vary depending on growth rate at the same age, and SG pigs may require higher dietary SID AA levels than FG pigs to achieve similar productive performance

Evaluation of Alternative High-Throughput Sequencing Methodologies for the Monitoring of Marine Picoplanktonic Biodiversity Based on rRNA Gene Amplicons

16 pages, 6 figures, 2 tablesSequencing of rRNA gene polymerase chain reaction amplicons (rRNA tags) is the most common approach for investigating microbial diversity. The recent development of high-throughput sequencing (HTS) technologies has enabled the exploration of microbial biodiversity at an unprecedented scale, greatly expanding our knowledge on the microbiomes of marine ecosystems. These approaches provide accurate, fast, and cost efficient observations of the marine communities, and thus, may be suitable tools in biodiversity monitoring programs. To reach this goal, consistent and comparable methodologies must be used over time and within sites. Here, we have performed a cross-platform study of the two most common HTS methodologies, i.e., 454-pyrosequencing and Illumina tags to evaluate their usefulness in biodiversity monitoring and assessment of environmental status. Picoplankton biodiversity has been compared through both methodologies by sequencing the 16 and 18 S rRNA genes of a set of samples collected in the coast of Barcelona (NW Mediterranean). The results show that, despite differences observed in the rare OTUs retrieved, both platforms provide a comparable view of the marine picoplankton communities. On a taxonomic level, there was an accurate overlap in the detected phyla between the two methods and the overall estimates of alpha- and betadiversity were comparable. In addition, we explored the concept of “indicator species” and found that certain taxa (i.e., members of the Gammaproteobacteria among others) as well as the ratio between some phylogenetic groups (i.e., the ratio of Alphaproteobacteria/Gammaproteobacteria, Alteromonas/SAR11, and Alteromonas + Oceanospirillales/SAR11) have potential for being useful indicators of environmental status. The data show that implementing new protocols and identifying indicators of environmental status based on rRNA amplicon sequencing is feasible, and that is worth exploring whether the identified indices are universally applicableThis manuscript is a result of DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing GEnS) project, funded by the European Union (grant agreement no. 308392), and a MINECO Grant GRADIENTS Fine-scale structure of cross-shore GRADIENTS along the Mediterranean coast (CTM2012-39476-C02)Peer Reviewe