Publications

Vulnerability of marine biodiversity to ocean acidification: A meta-analysis

AMAP Assessment 2013: Arctic Ocean Acidification

Paradigms in the Recovery of Estuarine and Coastal Ecosystems

Operationalizing Ocean Health: Toward Integrated Research on Ocean Health and Recovery to Achieve Ocean Sustainability

Protecting the ocean has become a major goal of international policy as human activities increasingly endanger the integrity of the ocean ecosystem, often summarized as “ocean health.” By and large, efforts to protect the ocean have failed because, among other things, (1) the underlying socio-ecological pathways have not been properly considered, and (2) the concept of ocean health has been ill defined. Collectively, this prevents an adequate societal response as to how ocean ecosystems and their vital functions for human societies can be protected and restored. We review the confusion surrounding the term “ocean health” and suggest an operational ocean-health framework in line with the concept of strong sustainability. Given the accelerating degeneration of marine ecosystems, the restoration of regional ocean health will be of increasing importance. Our advocated transdisciplinary and multi-actor framework can help to advance the implementation of more active measures to restore ocean health and safeguard human health and well-being.

Trace metals in deep ocean waters: A review

A response of experimental rocky shorecommunities to nutrient additions

Low water column nitrogen fixation in the Mediterranean Sea: basin-wide experimental evidence

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 64:135-147 (2011) - DOI: https://doi.org/10.3354/ame01511 Low water column nitrogen fixation in the Mediterranean Sea: basin-wide experimental evidence Nona S. R. Agawin1,*, Antonio Tovar-Sanchez2, Lucas J. Stal3,4, Marta Alvarez2,5, Susana Agustí2, Carlos M. Duarte2 1Interdisciplinary Ecology Group, Biology Department, Universidad de las Islas Baleares, 07122 Palma de Mallorca, Spain 2Department of Global Change Research, IMEDEA (UIB-CSIC), Instituto Mediterraneo de Estudios Avanzados, 07190 Esporles, Mallorca, Spain 3Department of Marine Microbiology, Netherlands Institute of Ecology (NIOO KNAW), Yerseke, The Netherlands 4Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands 5Present address: IEO, Centro de A Coruña, Apdo. 130, 15080, A Coruña, Spain *Email: ieanar@uib.es ABSTRACT: The abundance and nitrogen fixation rates of Trichodesmium sp. integrated down to the deep chlorophyll maximum as well as nitrogen fixation rates in size-fractionated discrete surface water samples were measured across the Mediterranean Sea. The abundance of Trichodesmium sp. was generally low (<50 trichomes m–3), except at one station in the Tyrrhenian Sea where the water temperature was >20°C and Trichodesmium sp. was present at a higher density (ca. 700 trichomes m–3). Across the basin, size-fractionated nitrogen fixation rates were low (<250 nmol N2 m–3 h–1). The highest rate was measured at a station characterized by relatively high concentrations of total ­dissolved P and dissolved Fe. High δ15N values (8.04 ± 2.03‰) of the particulate organic nitrogen were in accordance with the observed low water column nitrogen fixation rates across the Mediterranean Sea. KEY WORDS: Nitrogen fixation · Trichodesmium sp. · Mediterranean Sea Full text in pdf format PreviousNextCite this article as: Agawin NSR, Tovar-Sanchez A, Stal LJ, Alvarez M, Agustí S, Duarte CM (2011) Low water column nitrogen fixation in the Mediterranean Sea: basin-wide experimental evidence. Aquat Microb Ecol 64:135-147. https://doi.org/10.3354/ame01511 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 64, No. 2. Online publication date: August 04, 2011 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2011 Inter-Research.

Impact of mooring activities on carbon stocks in seagrass meadows

Abstract Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (C org ) stocks, which may contribute to increasing atmospheric CO 2 . This study presents the first estimates of loss of C org stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The C org stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary C org stores and the lack of further accumulation of C org . On average, undisturbed meadows had accumulated ~6.4 Kg C org m −2 in the upper 50 cm-thick deposits at a rate of 34 g C org m −2 yr −1 . The comparison of C org stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg C org m −2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of C org storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation.

Delírio de infestação parasitária associado a diálise tratado com aripiprazol.

Carbon dioxide and methane concentrations and their isotopic composition at the air-sea interface of Red Sea mangrove forests

Meridional and zonal changes in water properties along the continental slope off central and northern Chile

The Humboldt-09 cruise covered a narrow meridional band along the Chilean continental slope (44–23º S). Here we use physical and biochemical data from a long meridional section (4000 km) and three short zonal sections (100 km) to describe the distribution of the different water masses found in this region. Six water masses were identified: Subantarctic Water (SAAW), Summer Subantarctic Water (SSAW), Subtropical Water (STW), Equatorial Subsurface Water (ESSW), Antarctic Intermediate Water (AAIW), and Pacific Deep Water (PDW). For the first time, a novel set of source water mass properties (or water types) is introduced for SSAW, and nutrient and dissolved oxygen water types are proposed for all the water masses. Optimum multiparameter (OMP) analysis was used through an iterative process to obtain a sound definition of the water types that minimizes the residuals of the method. Both the classic OMP and the quasi-extended OMP models reproduced the data rather well. Finally, the spatial distribution of the different water masses was calculated with the quasi-extended OMP, which is not influenced by the respiration of organic matter. The distribution of the different water masses is presented over the meridional and zonal transects and in property-property diagrams. A smooth meridional transition from subantarctic to tropical and equatorial water masses is observed in this area. This transition takes place in surface, central, and intermediate waters over distances of the order of 1000 km. The meridional transition contrasts with the abrupt zonal changes found in the cross-slope direction, which are of comparable magnitude but over distances of the order of 100 km. Both AAIW and SAAW (fresh and well oxygenated) partially mix with the hypoxic ESSW and, therefore, play an important role in the ventilation of the southern part of the oxygen minimum zone.

La frontera norte se calienta

Self-organized sulfide-driven traveling pulses shape seagrass meadows

Seagrasses provide multiple ecosystem services and act as intense carbon sinks in coastal regions around the globe but are threatened by multiple anthropogenic pressures, leading to enhanced seagrass mortality that reflects in the spatial self-organization of the meadows. Spontaneous spatial vegetation patterns appear in such different ecosystems as drylands, peatlands, salt marshes, or seagrass meadows, and the mechanisms behind this phenomenon are still an open question in many cases. Here, we report on the formation of vegetation traveling pulses creating complex spatiotemporal patterns and rings in Mediterranean seagrass meadows. We show that these structures emerge due to an excitable behavior resulting from the coupled dynamics of vegetation and porewater hydrogen sulfide, toxic to seagrass, in the sediment. The resulting spatiotemporal patterns resemble those formed in other physical, chemical, and biological excitable media, but on a much larger scale. Based on theory, we derive a model that reproduces the observed seascapes and predicts the annihilation of these circular structures as they collide, a distinctive feature of excitable pulses. We show also that the patterns in field images and the empirically resolved radial profiles of vegetation density and sediment sulfide concentration across the structures are consistent with predictions from the theoretical model, which shows these structures to have diagnostic value, acting as a harbinger of the terminal state of the seagrass meadows prior to their collapse.

Consulta Popular de Origen Ciudadano

An approach to measurement of particle flux and sediment retention within seagrass (Posidonia oceanica) meadows

Apendicite necrotizante como complicação da varicela: relato de caso e revisão da literatura

MALASPINA_LEG5 Cruise, RV Hespérides

Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 to 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidising marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.