Archive for February, 2017



Ocean acidification examined with organisations and institutes

The Science and Technology Committee holds its first evidence session to examine ‘ocean acidification’ with organisations that were involved with the UK Ocean Acidification Research Programme, and with institutes that research ocean acidification in the UK’s overseas territories. The session considers the monitoring of ocean acidification, its impacts and the funding of marine science.

Witnesses

Wednesday 1 March 2017, Wilson Room, Portcullis House

At 9.30am

Dr Carol Turley, Senior Scientist, Plymouth Marine Laboratory
Dr Ceri Lewis, Senior Lecturer in Marine Biology, University of Exeter
Dr Alex Poulton, Principal Researcher in Marine Ecology and Biogeochemistry, National Oceanography Centre
Dr Ned Garnett, Associate Director Research, Natural Environment Research Council

At 10.30am

Professor Nicholas Bates, Director of Research, Bermuda Institute of Ocean Sciences
Dr Melody Clark, Project Leader, British Antarctic Survey

Further information and media coverage.

An overview upon CO₂ – possible source of ocean acidification

The interest upon CO₂ concentrations introduced in the atmosphere by human activities enhances year after year because of the consequences on the atmosphere, land and oceans. Many studies showed that changes in the ocean carbon cycle are due to the absorption of anthropogenic CO₂ from the atmosphere. The increase of CO₂ has been correlated with the pH falling of seawaters, promoting a critical process known as acidification. Ocean acidification could modify many biochemical cycles and functioning of marine organisms. The aim of this paper is to demonstrate the chemistry behaviour of CO₂ on seawaters. Once dissolved in seawater, CO₂ reacts with water to form carbonic acid (H₂CO₃). Ocean stores CO₂ as dissolved inorganic carbon (DIC) which remains in the form of dissolved CO₂ and H₂CO₃, while the rest is in the form of HCO₃⁻ and CO₃²⁻. Adding CO₂ to seawater, thus increase HCO₃⁻ that bring about a decrease in ocean water pH by increasing H+ concentration.

Continue reading ‘An overview upon CO₂ – possible source of ocean acidification’

Alaska OA Network enters 2017 with new structure

As the Alaska Ocean Acidification Network approaches its first birthday, a new executive committee and a set of working groups are poised to help advance ocean acidification in Alaska.

“We are very grateful for the broad spectrum of people who helped get the network off the ground,” said Darcy Dugan, the network director.  “As our interim steering committee expanded to 20 people over the course of the year, we decided we could best harness the energy by identifying a small and nimble executive committee and a number of topic-specific working groups.”

The working groups will be focusing on the topics of Outreach & Communication, K-12 Education, Engagement with the fishing community, Engagement with Tribes, Policy, and Research & Monitoring.  Most are set to have their first meeting in the next month. If you are interested in joining a working group, please email Darcy at dugan@aoos.org.

The first meeting of the new executive committee took place February 16.  Members include:

  • Darcy Dugan– Alaska Ocean Observing System (Alaska OA Network Director)
  • Shallin Busch – NOAA Ocean Acidification Program
  • Dorothy Childers – Alaska Marine Conservation Council
  • Wiley Evans – Hakai Institute
  • Bob Foy – NOAA AFSC Kodiak Lab
  • Davin Holen – Alaska Sea Grant
  • Jeremy Mathis – NOAA Arctic Program/UAF Ocean Acidification Research Center

Summaries from committee meetings and updates from working groups will be posted on the Alaska OA Network website under “Network documents“.

Further information.

Deep oceans face starvation by end of century

The deep ocean floor, earth’s largest habitat, will be starved of food by the end of this century, scientists have warned.

New research published on open-access journal Elementa today shows that food supply to some areas of the Earth’s deep oceans will decline by up to half by 2100.

Dr Andrew Sweetman, based at the Lyell Centre for Earth and Marine Science and Technology at Heriot-Watt University in Edinburgh, and colleagues from 20 of the world’s leading oceanographic research centres have used earth system models and projected climate change scenarios, developed for the Intergovernmental Panel on Climate Change (IPCC), to quantify impending changes to deep oceans.

The team looked at a number of sea and ocean beds, from the Arctic to Antarctic Oceans, focusing on bathyal (200-3000m) and abyssal (3000-6000m) depths. As well as measuring how the deep oceans’ food sources will decline, the team examined the impact that increased seabed temperatures, declining oxygen levels and increasingly acidic seawater will have, under the sea and across the planet.

Sweetman, associate professor at Heriot-Watt’s Lyell Centre for Earth and Marine Science and Technology, said: “The rate of change underway in our oceans is faster than at any point we know of in geological history.

Continue reading ‘Deep oceans face starvation by end of century’

Major impacts of climate change on deep-sea benthic ecosystems

The deep sea encompasses the largest ecosystems on Earth. Although poorly known, deep seafloor ecosystems provide services that are vitally important to the entire ocean and biosphere. Rising atmospheric greenhouse gases are bringing about significant changes in the environmental properties of the ocean realm in terms of water column oxygenation, temperature, pH and food supply, with concomitant impacts on deep-sea ecosystems. Projections suggest that abyssal (3000–6000 m) ocean temperatures could increase by 1°C over the next 84 years, while abyssal seafloor habitats under areas of deep-water formation may experience reductions in water column oxygen concentrations by as much as 0.03 mL L–1 by 2100. Bathyal depths (200–3000 m) worldwide will undergo the most significant reductions in pH in all oceans by the year 2100 (0.29 to 0.37 pH units). O2 concentrations will also decline in the bathyal NE Pacific and Southern Oceans, with losses up to 3.7% or more, especially at intermediate depths. Another important environmental parameter, the flux of particulate organic matter to the seafloor, is likely to decline significantly in most oceans, most notably in the abyssal and bathyal Indian Ocean where it is predicted to decrease by 40–55% by the end of the century. Unfortunately, how these major changes will affect deep-seafloor ecosystems is, in some cases, very poorly understood. In this paper, we provide a detailed overview of the impacts of these changing environmental parameters on deep-seafloor ecosystems that will most likely be seen by 2100 in continental margin, abyssal and polar settings. We also consider how these changes may combine with other anthropogenic stressors (e.g., fishing, mineral mining, oil and gas extraction) to further impact deep-seafloor ecosystems and discuss the possible societal implications.

Continue reading ‘Major impacts of climate change on deep-sea benthic ecosystems’

IMBIZO 5: “Marine biosphere research for a sustainable ocean: Linking ecosystems, future states and resource management”, 2-5 October 2017, Woods Hole, USA

Deadline for abstract submission: 30 May 2017!

The fifth IMBeR IMBIZO (the Zulu word for a gathering) will be hosted by the Ocean, Carbon & Biogeochemistry Group at the Woods Hole Oceanographic Institution, Woods Hole, MA, USA from 2-6 October 2017.

IMBIZO 5 will follow the usual format of three concurrent but interacting workshops. The three workshops are:

  • Critical constraints on future projections of marine systems (co-Chairs: Laurent Bopp and Eric Galbraith)
  • Metabolic diversity and evolution in marine biogeochemical cycling and ocean ecosystem processes (co-Chairs: Gerhard Herndl and Tatiana Rynearson)
  • Management Strategy Evaluation: Achieving transparency in natural resource management by quantitatively bridging social and natural science uncertainties (co-Chairs: Ingrid van Putten and Cisco Werner)

To ensure an environment conducive to interaction and discussion, each workshop will be limited to around 40 participants. For a diversity of scientific interests, participants will be selected according to their research interests and the abstracts that they submit.

Choose a workshop, and submit an abstract!

Further information.

Uncertain future for Southern Ocean phytoplankton

A new review of scientific research into the impact of climate change on Southern Ocean phytoplankton has revealed uncertainty about the future of the single-celled plants at the base of the ocean food chain, which play a key role in reducing atmospheric carbon.

A range of climate-induced stressors, from warming seas and increased ocean acidification to reductions in salinity and sea ice, is expected to alter phytoplankton communities across the Southern Ocean.

But a review of the latest scientific research, by IMAS PhD student Stacy Deppeler in collaboration with the Australian Antarctic Division and ACE CRC, has revealed that a clear trend of how Southern Ocean phytoplankton are affected is not expected to become apparent until mid-century, by which time the changes may be too far progressed to mitigate or reverse.

“While a fundamental part of the ecosystem is changing in ways that could have global implications, there’s uncertainty about exactly what the changes and their impact will be,” Ms Deppeler said.

Continue reading ‘Uncertain future for Southern Ocean phytoplankton’

Southern Ocean phytoplankton in a changing climate

Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.

Continue reading ‘Southern Ocean phytoplankton in a changing climate’

Spatial and temporal controls on the inorganic carbon system of the Western Arctic Ocean

The Arctic Ocean plays a critical role in the global carbon cycle. It is believed to be particularly sensitive to the effects of climate change, is already undergoing dramatic changes, and is therefore important to study in that context. Most studies of the inorganic carbon system in the Western Arctic focus on hydrographic datasets from summer and/or fall (July-October), and do not consider the full response of the system to the timing of ice retreat, organic matter production and remineralization, and ice advance. Here we present the first dataset to investigate the spatial and temporal controls on the inorganic carbon system from early spring (pre-phytoplankton), late spring (initial phytoplankton bloom), summer (post-bloom), and fall in 2014. Our results suggest that the timing of ice retreat has important implications for the length of the phytoplankton growing season, and thus influences the magnitude of biological carbon cycling. We extend our analysis to include high-resolution temporal estimates of air-sea CO2 flux, and estimate a total annual CO2 uptake in the Chukchi Sea of ~7.7 Tg C. This is the first dataset to evaluate the importance of different seasonal observations within one year on the annual uptake of CO2 in the western Arctic Ocean. Our results show that extrapolations from one observational dataset result in large over- or underestimations of annual CO2 flux.

Continue reading ‘Spatial and temporal controls on the inorganic carbon system of the Western Arctic Ocean’

Experimental evidence of formation of transparent exopolymer particles (TEP) and POC export provoked by dust addition under current and high pCO2 conditions

The evolution of organic carbon export to the deep ocean, under anthropogenic forcing such as ocean warming and acidification, needs to be investigated in order to evaluate potential positive or negative feedbacks on atmospheric CO2 concentrations, and therefore on climate. As such, modifications of aggregation processes driven by transparent exopolymer particles (TEP) formation have the potential to affect carbon export. The objectives of this study were to experimentally assess the dynamics of organic matter, after the simulation of a Saharan dust deposition event, through the measurement over one week of TEP abundance and size, and to evaluate the effects of ocean acidification on TEP formation and carbon export following a dust deposition event. Three experiments were performed in the laboratory using 300 L tanks filled with filtered seawater collected in the Mediterranean Sea, during two ‘no bloom’ periods (spring at the start of the stratification period and autumn at the end of this stratification period) and during the winter bloom period. For each experiment, one of the two tanks was acidified to reach pH conditions slightly below values projected for 2100 (~ 7.6–7.8). In both tanks, a dust deposition event of 10 g m-2 was simulated at the surface. Our results suggest that Saharan dust deposition triggered the abiotic formation of TEP, leading to the formation of organic-mineral aggregates. The amount of particulate organic carbon (POC) exported was proportional to the flux of lithogenic particles to the sediment traps. Depending on the season, the POC flux following artificial dust deposition ranged between 38 and 90 mg m-2 over six experimental days. Such variability is likely linked to the seasonal differences in the quality and quantity of TEP-precursors initially present in seawater. Finally, these export fluxes were not significantly different at the completion of the three experiments between the two pH conditions.

Continue reading ‘Experimental evidence of formation of transparent exopolymer particles (TEP) and POC export provoked by dust addition under current and high pCO2 conditions’


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