BIOACID Science Portrait – Maria Moreno de Castro: “A data detective tracking uncertainties”

Maria Moreno de Castro, modeler at Helmholtz-Zentrum Geesthacht (HZG), became a scientist because she likes to solve mysteries. Just like a detective, she tries to track uncertainties in scientific findings. “Our daily life is full of uncertainties. In science it’s the same: There are many outcomes, any solutions, many responses that we are not certain and we don’t know. We have to deal with this uncertainty, we have to understand it and know the origins.”

Maria Moreno used model calculations to get a grip on these uncertainties. By using mathematical approaches, she calculates thresholds below which variabilities will not escalate and mask the effect an experiment tries to explore. “Particularly in ecology of ocean acidification the answer is not black or white. Always there will be a grey area”, the young scientist explains. “This is also important when we communicate to policy makers, because it is really not possible.to give just a value to the effect of ocean acidification, but possible scenarios with their probabilities. This is highly difficult, and the best we can do from science.”

Further information.

Investigating controls on boron isotope ratios in shallow marine carbonates

The boron isotope-pH proxy has been widely used to reconstruct past ocean pH values. In both planktic foraminifera and corals, species-specific calibrations are required in order to reconstruct absolute values of pH, due to the prevalence of so-called vital effects — physiological modification of the primary environmental signals by the calcifying organisms. Shallow marine abiotic carbonate (e.g. ooids and cements) could conceivably avoid any such calibration requirement, and therefore provide a potentially useful archive for reconstructions in deep (pre-Cenozoic) time. However, shallow marine abiotic carbonates could also be affected by local shifts in pH caused by microbial photosynthesis and respiration, something that has up to now not been fully tested. In this study, we present boron isotope measurements from shallow modern marine carbonates, from the Bahama Bank and Belize to investigate the potential of using shallow water carbonates as pH archives, and to explore the role of microbial processes in driving nominally ‘abiogenic’ carbonate deposition. For Bahama bank samples, our boron-based pH estimates derived from a range of carbonate types (i.e. ooids, peloids, hardground cements, carbonate mud, stromatolitic micrite and calcified filament micrite) are higher than the estimated modern mean-annual seawater pH values for this region. Furthermore, the majority (73%) of our marine carbonate-based pH estimates fall out of the range of the estimated pre-industrial seawater pH values for this region. In shallow sediment cores, we did not observe a correlation between measured pore water pH and boron-derived pH estimates, suggesting boron isotope variability is a depositional rather than early diagenetic signal. For Belize reef cements, conversely, the pH estimates are lower than likely in situ seawater pH at the time of cement formation. This study indicates the potential for complications when using shallow marine non-skeletal carbonates as marine pH archives. In addition, variability in δ11B based pH estimates provides additional support for the idea that photosynthetic CO2 uptake plays a significant role in driving carbonate precipitation in a wide range of shallow water carbonates.

Continue reading ‘Investigating controls on boron isotope ratios in shallow marine carbonates’

Acidification and warming affect prominent bacteria in two seasonal phytoplankton bloom mesocosms

In contrast to clear stimulatory effects of rising temperature, recent studies of the effects of CO2 on planktonic bacteria have reported conflicting results. To better understand the potential impact of predicted climate scenarios on the development and performance of bacterial communities, we performed bifactorial mesocosm experiments (pCO2 and temperature) with Baltic Sea water, during a diatom dominated bloom in autumn and a mixed phytoplankton bloom in summer. The development of bacterial community composition (BCC) followed well-known algal bloom dynamics. A principal coordinate analysis (PCoA) of bacterial OTUs (operational taxonomic units) revealed that phytoplankton succession and temperature were the major variables structuring the bacterial community whereas the impact of pCO2 was weak. Prokaryotic abundance and carbon production, and organic matter concentration and composition were partly affected by temperature but not by increased pCO2. However, pCO2 did have significant and potentially direct effects on the relative abundance of several dominant OTUs; in some cases, these effects were accompanied by an antagonistic impact of temperature. Our results suggest the necessity of high-resolution BCC analyses and statistical analyses at the OTU level to detect the strong impact of CO2 on specific bacterial groups, which in turn might also influence specific organic matter degradation processes.

Continue reading ‘Acidification and warming affect prominent bacteria in two seasonal phytoplankton bloom mesocosms’

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’


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