Quantifying the pH ‘vital effect’ in the temperate zooxanthellate coral Cladocora caespitosa: Validation of the boron seawater pH proxy

Boron isotopic and elemental systematics are used to define the vital effects for the temperate shallow water Mediterranean coral Cladocora caespitosa. The corals are from a range of seawater pH conditions (pH_T ~ 7.6 to ~ 8.1) and environmental settings: (1) naturally living colonies harvested from normal pH waters offshore Levanto, (2) colonies transplanted nearby a subsea volcanic vent system, and (3) corals cultured in aquaria exposed to high (700 μatm) and near present day (400 μatm) pCO₂ levels. B/Ca compositions measured using laser ablation inductively coupled mass spectrometry (LA-ICPMS) show that boron uptake by C. caespitosa cultured at different pCO₂ levels is independent of ambient seawater pH being mainly controlled by temperature-dependent calcification. In contrast, the boron isotope compositions (δ¹¹B_carb) of the full suite of corals determined by positive thermal ionisation mass spectrometry (PTIMS) shows a clear trend of decreasing δ¹¹B_carb (from 26.7 to 22.2‰) with decreasing seawater pH, reflecting the strong pH dependence of the boron isotope system. The δ¹¹B_carb compositions together with measurements of ambient seawater parameters enable calibration of the boron pH proxy for C. caespitosa, by using a new approach that defines the relationship between ambient seawater pH (pH_sw) and the internally controlled pH at the site of calcification (pH_biol). C. caespitosa exhibits a linear relationship between pH_sw and the shift in pH due to physiological processes (ΔpH = pH_biol − pH_sw) giving the regression ΔpH_Clad = 4.80 − 0.52 × pH_sw for this species. We further apply this method (“ΔpH–pH_sw”) to calibrate tropical species of Porites, Acropora, and Stylophora reported in the literature. The temperate and tropical species calibrations are all linearly correlated (r² > 0.9) and the biological fractionation component (ΔpH) between species varies within ~ 0.2 pH units. Our “ΔpH–pH_sw” approach provides a robust and accurate tool to reconstruct palaeoseawater pH_sw for both temperate and tropical corals, further validating the boron fractionation factor (α_B3–B4 = 1.0272) determined experimentally by Klochko et al. (2006) and the boron isotope pH proxy, both of which have been the foci of considerable debate.

National Ocean Council; Development of Strategic Action Plans for the National Policy for the Stewardship of the Ocean, Our Coasts, and the Great Lakes

On July 19, 2010, President Obama signed Executive Order 13547 establishing a National Policy for the Stewardship of the Ocean, our Coasts, and the Great Lakes (“National Policy”). That Executive Order adopts the Final Recommendations of the Interagency Ocean Policy Task Force (“Final Recommendations”) and directs Federal agencies to take the appropriate steps to implement them. The Executive Order creates an interagency National Ocean Council (NOC) to strengthen ocean governance and coordination, identifies nine priority actions for the NOC to pursue, and adopts a flexible framework for effective coastal and marine spatial planning to address conservation, economic activity, user conflict, and sustainable use of the ocean, our coasts and the Great Lakes.

Isotopic tools for protecting the seas

The oceans and seas are our greatest natural resource, but they are under threat for many reasons. The IAEA operates one of the world´s leading centres for marine environmental protection, the Monaco-based Marine Environment Laboratory (MEL). The Laboratory applies nuclear and isotopic techniques to research and document pollution and other problems, and technically assists States facing threats to their lakes, seas, and coastal waters.

PhD Studentship: Effects of ocean acidification on shell characteristics in articulated brachiopods

Closing date for applications: 01 March 2011

Effects of ocean acidification on shell characteristics in articulated brachiopods

NERC PhD studentship funded by NERC grant NE/I019565/1: Shell composition and microstructure variation with pH in time and space.

Supervisors: Prof Lloyd Peck (BAS) & Dr Elizabeth Harper (Earth Sciences, Cambridge).

Full studentship funding is limited to UK and some EU citizens. For more details see
http://www.nerc.ac.uk/funding/available/postgrad/eligibility.asp

This PhD project forms part of a large, interdisciplinary research project to assess the impact of ocean acidification on life in the sea. It is in turn part of the NERC Thematic Programme to investigate biodiversity and ecosystem functioning on the planet. This project aims to address 4 questions:

1. How do shell microstructure and composition vary between animals currently living at different pH?
2. How do these shell characteristics vary within a species from the same site across the Anthropocene?
3. How do shell characteristics vary in brachiopods across geological periods with different CO2 levels?
4. How does growing articulated brachiopods in lowered pH conditions alter their shell characteristics?

Acid oceans demand greater reef care

The more humanity acidifies and warms the world’s oceans with carbon emissions, the harder we will have to work to save our coral reefs.

That’s the blunt message from a major new study by an international scientific team, which finds that ocean acidification and global warming will combine with local impacts like overfishing and nutrient runoff to weaken the world’s coral reefs right when they are struggling to survive.

Modelling by a team led by Dr Ken Anthony of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland’s Global Change Institute has found that reefs already overfished and affected by land runoff are likely to be more vulnerable to increasing CO2 in the atmosphere caused by the burning of fossil fuels.

Buoys assist BIOS’s ocean acidification project

Two new buoys have been deployed around Bermuda to contribute data to BIOS’s Bermuda Ocean Acidification and Coral reef Investigation [BEACON] project. The buoys are fitted with instrumentation which will measure in situ seawater temperature, salinity, dissolved oxygen, turbidity, chlorophyll, pCO2 and pH every three hours.

In early December BIOS researchers deployed the buoys at Crescent and Hog Reefs. The technology has been developed by the National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory for studies of coastal air-sea carbon exchange. The collaboration is part of a global network of carbon dioxide and ocean acidification time-series observations. By cross-referencing the information from the buoys with BIOS’ research on coral calcification rates at Hog and Crescent reefs, it will be possible to develop a better idea of how corals are responding to physical and chemical changes in the environment.

Bryozoan skeletal mineralogy and ocean acidification

Cheilostome bryozoans use 2 calcium carbonate biominerals to form their skeletons:

• calcite
• aragonite

Investigating the switch to aragonite

Calcite is the primitive biomineral for cheilostomes but since the Late Cretaceous several clades have switched to partly or completely aragonitic skeletons.

We are investigating the timing of these switches and their relationship to changing seawater chemistry.

Educational outreach: Ocean acidification, ecosystems, and climate

On February 5, JISAO scientist Nicholas Bond co-taught a class with Dr. Richard Feely of NOAA/PMEL called Ocean Acidification, Ecosystems, and Climate. The class was part of Sound Waters, an event sponsored by Washington State University Island County Beach Watchers in connection with the public education effort by that group.

Export of pacific carbon through the arctic archipelago to the North Atlantic

During an east-to-west transect through the Canadian Arctic Archipelago, dissolved inorganic carbon (DIC) and total alkalinity (TA) were measured. The composition of the waters throughout the Archipelago were computed using TA and δ¹⁸O data, and the carbon characteristics of these waters is examined. The influence of the Mackenzie River is primarily limited to the upper water column in the western Archipelago while the fraction of sea-ice melt water in the surface waters increases eastward with maximum values at the outflows of Jones and Lancaster Sounds. The depth of penetration of Pacific-origin upper halocline waters increases eastward through the Archipelago. In the western Archipelago, non-conservative variations in deep water DIC are used to compute a subsurface carbon surplus, which appears to be fueled by organic matter produced in the surface layer and by benthic respiration. The eastward transport of carbon from the Pacific, via the Arctic Archipelago, to the North Atlantic is estimated. The impact of increased export of sea-ice melt water to the North Atlantic is also discussed.

Towards recognition of physical and geochemical change in subarctic and Arctic seas

The advection of parent subarctic water masses, and their subsequent modification upon entering the Arctic Ocean and during transit of the pan-arctic system, has fundamental impacts on ice cover, ocean properties and ecosystem dynamics. The Canadian IPY project Canada’s Three Oceans (C3O), together with the international Joint Ocean Ice Study (JOIS), collected physical, chemical and biological information in 2007 and 2008 against which changes in the subarctic and arctic waters surrounding northern North America can be quantified. This paper presents physical and chemical data from 2007 to describe oceanic domains around northern North America, and offers conceptual frameworks against which linkages between the subarctic and arctic domains can be categorized. Ongoing changes include ocean warming, sea-ice melting, upper layer freshening, altered stratification, increased acidification and, in the subarctic Pacific, increased hypoxia.