Archive for the 'Science' Category

Impacts of ocean acidification on carboxylated carbon nanotube effects induced in the clam species Ruditapes philippinarum

Although the increased production of nanoparticles (NPs) has raised extensive concerns about the potential toxic effects on aquatic organisms, as well as the increasing evidences which documented the impact of ocean acidification (OA) on the physiology and fitness of marine invertebrates, limited number of studies reported their combined toxic effects. For these reasons, in the present study, we investigated the physiological and biochemical responses of one of the most economically important bivalve species in the World, the Manila clam Ruditapes philippinarum, after the exposure to an environmnetally relevant concentration of carboxylated carbon nanotubes and predicted OA conditions. The results showed that the organisms were not only susceptible to NPs but also to seawater acidification. Different responses between low pH and NPs for most tested biomarkers were observed, both in terms of physiological (respiration rate) and biochemical responses (metabolic capacity, oxitative status and neurotoxicity). Acidified pH significantly decreased the respiration rate and metabolism and increased the energy reserves consumption. Moreover, increase of the oxidative damage was also detected under this condition confirming that the mechanism of enhanced toxicity in the organisms should be attributed to lower aggregation state with more suspended NPs in acidified seawater, indicating that seawater acidification significantly influenced the impact of the used NPs in the exposed organisms.

Continue reading ‘Impacts of ocean acidification on carboxylated carbon nanotube effects induced in the clam species Ruditapes philippinarum’

Lessons from Earth’s deep past: climate change and ocean acidification 200 million years ago

Understanding ongoing climate change is a major scientific challenge. Climate events in the deep history of Earth can inform us about the possible extremes of greenhouse conditions, rates and magnitude of long-term climate change, and their consequences to the ocean and the biosphere. The end of the Triassic period was a time of greenhouse warming, driven by volcanic emission of CO2 and other gases from eruptions in the Central Atlantic Magmatic Province. The end-Triassic mass extinction is the biotic response to rapid environmental changes triggered by volcanism. Ocean acidification was likely a major factor driving the selective extinction of calcifying marine organisms.

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Ecological and socioeconomic strategies to sustain Caribbean coral reefs in a high-CO2 world

The Caribbean and Western Atlantic region hosts one of the world’s most diverse geopolitical regions and a unique marine biota distinct from tropical seas in the Pacific and Indian Oceans. While this region varies in human population density, GDP and wealth, coral reefs, and their associated ecosystem services, are central to people’s livelihoods. Unfortunately, the region’s reefs have experienced extensive degradation over the last several decades. This degradation has been attributed to a combination of disease, overfishing, and multiple pressures from other human activities. Furthermore, the Caribbean region has experienced rapid ocean warming and acidification as a result of climate change that will continue and accelerate throughout the 21st century. It is evident that these changes will pose increasing threats to Caribbean reefs unless imminent actions are taken at the local, regional and global scale. Active management is required to sustain Caribbean reefs and increase their resilience to recover from acute stress events. Here, we propose local and regional solutions to halt and reverse Caribbean coral reef degradation under ongoing ocean warming and acidification. Because the Caribbean has already experienced high coral reef degradation, we suggest that this region may be suitable for more aggressive interventions than might be suitable for other regions. Solutions with direct ecological benefits highlighted here build on existing knowledge of factors that can contribute to reef restoration and increased resilience in the Caribbean: (1) management of water quality, (2) reduction of unsustainable fishing practices, (3) application of ecological engineering, and (4) implementing marine spatial planning. Complementary socioeconomic and governance solutions include: (1) increasing communication and leveraging resources through the establishment of a regional reef secretariat, (2) incorporating reef health and sustainability goals into the blue economy plans for the region, and (3) initiating a reef labelling program to incentivize corporate partnerships for reef restoration and protection to sustain overall reef health in the region.

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Call for submissions for special issue: “The effects of ocean acidification on the species across the lower trophic levels in the pelagic realm”

Deadline for manuscript submissions: 31 July 2019

Special Issue description: The overarching aim of this Special Issue focuses on establishing how ocean acidification (OA) drives changes across pelagic species and communities from molecular to cellular to physiological to population levels and demonstrating our capacity to improve the forecasting and management of the emerging effects of OA in dynamic, complex systems. This Special Issue welcomes the integration of various complementary approaches, ranging from field experiments with laboratory manipulations to synthesis and modelling approaches with the aim to advance a mechanistic understanding across different levels of biological organization, as well as to improve the prediction of OA emerging effects. Studies can use a variety of natural systems that represent natural analogues for OA or are characterized by the variability that determines overall OA exposure in the pelagic realm. With topics describing the species sensitivity and resiliency aspects, biological thresholds, and OA-driven species distribution and habitat suitability modelling, this Special Issue aims to contribute to the overall biological vulnerability assessment of pelagic species and communities to OA. Studies that include multiple drivers are warranted if that will ultimately drive overall pelagic vulnerability or resilience to OA.

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Observing changes in ocean carbonate chemistry: our autonomous future

Our developing network of autonomous carbonate observations is currently targeted at surface ocean CO2 fluxes and compact ecosystem observatories. New integration of developed sensors on gliders and surface vehicles will increase our coastal and regional observational capability. Most autonomous platforms observe a single carbonate parameter, which leaves us reliant on the use of empirical relationships to constrain the rest of the carbonate system. Sensors now in development promise the ability to observe multiple carbonate system parameters from a range of vehicles in the near future.

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Proteomic responses to ocean acidification of the marine diazotroph Trichodesmium under iron-replete and iron-limited conditions

Growth and dinitrogen (N2) fixation of the globally important diazotrophic cyanobacteria Trichodesmium are often limited by iron (Fe) availability in surface seawaters. To systematically examine the combined effects of Fe limitation and ocean acidification (OA), T. erythraeum strain IMS101 was acclimated to both Fe-replete and Fe-limited concentrations under ambient and acidified conditions. Proteomic analysis showed that OA affected a wider range of proteins under Fe-limited conditions compared to Fe-replete conditions. OA also led to an intensification of Fe deficiency in key cellular processes (e.g., photosystem I and chlorophyll a synthesis) in already Fe-limited T. erythraeum. This is a result of reallocating Fe from these processes to Fe-rich nitrogenase to compensate for the suppressed N2 fixation. To alleviate the Fe shortage, the diazotroph adopts a series of Fe-based economic strategies (e.g., upregulating Fe acquisition systems for organically complexed Fe and particulate Fe, replacing ferredoxin by flavodoxin, and using alternative electron flow pathways to produce ATP). This was more pronounced under Fe-limited-OA conditions than under Fe limitation only. Consequently, OA resulted in a further decrease of N2- and carbon-fixation rates in Fe-limited T. erythraeum. In contrast, Fe-replete T. erythraeum induced photosystem I (PSI) expression to potentially enhance the PSI cyclic flow for ATP production to meet the higher demand for energy to cope with the stress caused by OA. Our study provides mechanistic insight into the holistic response of the globally important N2-fixing marine cyanobacteria Trichodesmium to acidified and Fe-limited conditions of future oceans.

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OA-ICC bibliographic database updated

An updated version of the OA-ICC bibliographic database is available online.

The database currently contains more than 5,520 references and includes citations, abstracts and assigned keywords. Updates are made every month.

The database is available as a group on Mendeley. Subscribe online or, for a better user experience, download the Mendeley Desktop application and sync with the group Ocean Acidification (OA-ICC). Please see the “User instructions” for further details.

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Ocean acidification in the IPCC AR5 WG II

OUP book