OA-ICC December calendar: 18/12- “All OA roads lead to Monaco”

Count down the days until 2015 together with the OA-ICC! Each day of December you will find a short story on the OA-ICC news stream highlighting an ocean acidification project, effort, or resource.

Discover today’s story below: “All OA roads lead to Monaco”.


Continue reading ‘OA-ICC December calendar: 18/12- “All OA roads lead to Monaco”’

Preface: Field investigation of ocean acidification effects in northwest European seas

The pH of the ocean is being lowered by its uptake of anthropogenic atmospheric carbon dioxide (CO2), produced as a result of combustion of fossil fuels and land use changes. This acidification is especially pronounced in the surface ocean, where the loadings of anthropogenic CO2 are greatest because of the direct contact with the atmosphere. Much of the work to date has tried to elucidate the biological and biogeochemical consequences of this surface ocean acidification by carrying out studies in the laboratory. This paper gives an overview of work carried out on a cruise in northwest European shelf seas in June and July 2011. The objectives of the cruise were to study ocean acidification impacts by collecting observations from the natural environment across carbonate chemistry gradients, and by carrying out short-term (96 h) bioassay CO2 perturbation experiments on natural populations. In both cases the aim was to enhance our understanding of the impacts of ocean acidification through studies of the natural world with as little artificiality as possible. Here we give an overview of the conditions encountered during this cruise and give a brief introduction to the individual studies that were carried out and whose results are presented in the separate papers in this special issue.

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CO2 and nutrient-driven changes across multiple levels of organization in Zostera noltii ecosystems (update)

Increasing evidence emphasizes that the effects of human impacts on ecosystems must be investigated using designs that incorporate the responses across levels of biological organization as well as the effects of multiple stressors. Here we implemented a mesocosm experiment to investigate how the individual and interactive effects of CO2 enrichment and eutrophication scale-up from changes in primary producers at the individual (biochemistry) or population level (production, reproduction, and/or abundance) to higher levels of community (macroalgae abundance, herbivory, and global metabolism), and ecosystem organization (detritus release and carbon sink capacity). The responses of Zostera noltii seagrass meadows growing in low- and high-nutrient field conditions were compared. In both meadows, the expected CO2 benefits on Z. noltii leaf production were suppressed by epiphyte overgrowth, with no direct CO2 effect on plant biochemistry or population-level traits. Multi-level meadow response to nutrients was faster and stronger than to CO2. Nutrient enrichment promoted the nutritional quality of Z. noltii (high N, low C : N and phenolics), the growth of epiphytic pennate diatoms and purple bacteria, and shoot mortality. In the low-nutrient meadow, individual effects of CO2 and nutrients separately resulted in reduced carbon storage in the sediment, probably due to enhanced microbial degradation of more labile organic matter. These changes, however, had no effect on herbivory or on community metabolism. Interestingly, individual effects of CO2 or nutrient addition on epiphytes, shoot mortality, and carbon storage were attenuated when nutrients and CO2 acted simultaneously. This suggests CO2-induced benefits on eutrophic meadows. In the high-nutrient meadow, a striking shoot decline caused by amphipod overgrazing masked the response to CO2 and nutrient additions. Our results reveal that under future scenarios of CO2, the responses of seagrass ecosystems will be complex and context-dependent, being mediated by epiphyte overgrowth rather than by direct effects on plant biochemistry. Overall, we found that the responses of seagrass meadows to individual and interactive effects of CO2 and nutrient enrichment varied depending on interactions among species and connections between organization levels.

Continue reading ‘CO2 and nutrient-driven changes across multiple levels of organization in Zostera noltii ecosystems (update)’

Bacteriostatic suppression in Norway lobster (Nephrops norvegicus) exposed to manganese or hypoxia under pressure of ocean acidification

Future ocean acidification (OA) and warming following climate change elicit pervasive stressors to the inhabitants of the sea. Previous experimental exposure to OA for 16 weeks at pH levels predicted for 2100, has shown to result in serious immune suppression of the Norway lobster, Nephrops norvegicus. The lobsters are currently affected by stressors such as periodical hypoxia inducing high levels of bioavailable manganese (Mn). Here, we aimed to investigate possible effects of interactions between OA and these stressors on total hemocyte counts (THC) and on recovery of inoculated bacteria in the lobsters, measured as a proxy for bacteriostatic response. The effects were judged by following numbers of culturable Vibrio parahaemolyticus in hepatopancreas, 4 and 24 h post inoculation in lobsters kept in replicate tanks with six different treatments; either ambient (pCO2∼ 500 μatm/pH∼8.1 units) or CO2 manipulated seawater (OA; pCO2 1550 μatm/pH∼7.6 units) for 8 weeks. During the last two weeks additional stress of either hypoxia (∼23% oxygen saturation) or Mn (∼9 mgL−1) was added except in control treatments. Our results showed clear effect on bacteriostatic response in Norway lobsters exposed to these stressors. In lobster kept in ambient seawater without additional stressors the number of culturable bacteria in hepatopancreas was reduced by ∼ 34%. In combined treatment of ambient seawater and hypoxia the reduction was ∼23%, while in the Mn-exposed animals, there was no reduction at all. This was also the case in all OA-treatments where mean numbers of culturable V. parahaemolyticus tended to increase. In lobsters from ambient seawater with or without hypoxia, the total hemocyte count (THC) was not significantly different as was also the case in OA without additional stressors. However, in OA-treatments combined with either hypoxia or Mn, THC was reduced by ∼ 35%.While the reduction of culturable V. parahaemolyticus in lobsters was clearly affected by these stressors, we found no notable effects on growth, survival or hemolytic properties of the bacteria itself. Thus, we conclude that this predicted stress scenario is beneficial for the pathogen in its interaction with the host. As OA proceeds, it may force the health of the ecologically and economically important N. norvegicus to a tipping point if exposed to more short-term stressors such as the periodical events of hypoxia and Mn. This could impact lobster condition and biomass and may as well increase the risk for bacterial transmission to consumers.

Continue reading ‘Bacteriostatic suppression in Norway lobster (Nephrops norvegicus) exposed to manganese or hypoxia under pressure of ocean acidification’

Tenure Track Assistant Professor in Chemical Oceanography

For full consideration applications should be received by 1 March 2015.

The School of Fisheries and Ocean Sciences (SFOS) at the University of Alaska Fairbanks (UAF) seeks applications from exceptional candidates for a tenure-track assistant professor position in chemical oceanography. Specialties of interest include ocean acidification, marine inorganic carbon chemistry, carbon biogeochemistry, carbon cycle-climate interactions, isotope biogeochemistry, and evaluation of the biological impact of ocean acidification. The school is particularly interested in applicants whose research plan involves the new ice-capable, Global Class Research Vessel Sikuliaq.

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Latin-American Workshop on Ocean Acidification (LAOCA), 9-16 November 2014, Dichato, Chile

pic LAOCAThe Ocean Acidification International Coordination Centre (OA-ICC) and the Millennium Institute of Oceanography and the Center for the Study of Multiple-Drivers on Marine Socio-Ecological Systems (MUSELS) at the Universidad de Concepción sponsored and coordinated an ocean acidification workshop on 9-16 November 2014 at the Universidad de Concepción Field Station, Dichato, Chile. Nineteen students, with a breakdown of 7 male to 12 female, from 7 Latin American countries (Chile, Brazil, Ecuador, Peru, Argentina, Mexico and Columbia) participated. Students ranged from those who were in the process of obtaining their Masters or PhD degrees, postdoctoral students, and researchers/faculty. Students represented multiple sub-disciplines of biology and chemistry in oceanography.

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OA-ICC December calendar: 17/12- “OA research know-how”

Count down the days until 2015 together with the OA-ICC! Each day of December you will find a short story on the OA-ICC news stream highlighting an ocean acidification project, effort, or resource.

Discover today’s story below: “OA research know-how”.

Continue reading ‘OA-ICC December calendar: 17/12- “OA research know-how”’

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