Published 27 October 2011
The Associated Student’s Coastal Fund of UCSB has announced that they will be contributing a $14,000 grant to the Environmental Defense Center (EDC) in support of the Coast and Ocean program.
The grant is specifically to underwrite EDC’s efforts to address the significant environmental impacts of ocean acidification in the Santa Barbara Channel and in oceans throughout the world. The grant will also support a conference at UCSB, which will bring together experts on ocean chemistry issues to educate the University community about ongoing research and decision-making processes, to engender understanding of the roles of the various stakeholders and regulators, and to encourage student and faculty engagement in the policy-making process.
Continue reading ‘Coastal fund support EDC ocean acidification project’
Published 27 October 2011
Sudden addition of carbon dioxide to the atmosphere can reduce the CaCO3 saturation and weaken the biocalcification potential of marine organisms in shallow water and in open marine settings. In this study, the response of an Aptian neritic carbonate environment to sudden addition of carbon dioxide at the beginning of Oceanic Anoxic Event 1a is investigated. The beginning of the OAE1a was coupled with a major perturbation on the carbon cycle as indicated by a negative carbon isotope excursion in the sedimentary record. This isotope anomaly is regarded as a proxy for massive addition of volcanic or methane-derived CO2 to the atmosphere within only a few 104 years. The impact of a rapid change in atmospheric pCO2 on biocalcifiers in low latitude shallow-water settings can be studied in a well preserved Aptian carbonate shelf succession cropping out today in the Aralar mountains (NE Spain). The Madotz section (N Spain) preserves a continuous shallow water record that was deposited on a mid-latitude, Atlantic-oriented mixed siliciclastic-carbonate ramp. Lower Aptian sediments consist of two neritic limestone successions separated by orbitolinid-rich marlstone enriched in organic matter. The lower neritic limestone succession ends with a submarine hardground and the transition from the lower neritic limestone to the orbitolinid marlstone coincides with a negative spike in the organic carbon isotope record. This negative spike can be correlated with the negative carbon isotope anomaly marking the base of OAE1a. The paleoecological change coinciding with the base of OAE1a occurred at a time of sea level rise and it coincided with a demise of heavily calcified nannoconids in the Tethys and Pacific Oceans. The paleoecological change observed in the Madotz section corresponds to a comparable change seen in the more distal and more expanded carbonate ramp section (Igaratza) at the Aralar Mountains. Ocean acidification caused by sudden increase in pCO2 may explain reduced calcification potential of some shallow water calcifiers. Calcification crisis was amplified by rising sea level, increasing temperatures and increased flux of detrital material and nutrients from continents into coastal seas.
Continue reading ‘The Madotz Urgonian platform (Aralar, northern Spain): paleoecological changes in response to Early Aptian global environmental events’
Published 27 October 2011
In view of rising atmospheric CO2 concentrations, the question if the marine biological carbon pump will increase or decrease in efficiency as ocean acidification progresses becomes central for predictions of future atmospheric pCO2. Aggregation and sinking of aggregates contributes significantly to the flux of carbon to depths and changes in aggregation behavior will have far reaching consequences for the biological pump. The abundance and characteristics of Transparent Exopolymer Particles, TEP, are central in regulating aggregation. We investigated the impact of ocean acidification on the abiotic formation of TEP from their precursors. Our results demonstrate that, contrary to earlier suggestions, ocean acidification as expected in the future ocean has no impact on the equilibrium conditions between TEP and their precursors. However, if the carbonate system is altered by adding acid, which does not simulate the future ocean carbonate system correctly, TEP concentration increases with decreasing pH, presumably due to changes in total alkalinity (TA). This implies that abiotic TEP formation is sensitive to changes in TA, but not pH. The discrepancy in results caused by different experimental approaches emphasizes the fact that acidification experiments do not mimic future conditions adequately and may even be misleading.
Continue reading ‘The abiotic formation of TEP under different ocean acidification scenarios’
A comparison of the equations for photosynthesis and calcification in reef corals suggests that the two processes compete for available inorganic carbon; yet reef corals exhibit simultaneous high rates of photosynthesis and calcification during daylight hours. Also, the extreme metabolic activity observed in corals at high irradiance requires a large net efflux of protons at sites of rapid calcification and respiration. Corals have resolved these problems through development of morphologies that separate the zone of rapid calcification (ZC) from the zone of rapid photosynthesis (ZP), with the fixed-carbon energy supply from the ZP being rapidly translocated to the ZC. Translocation of photosynthate from the ZP serves as a means of transporting protons to the ZC, where they are readily dissipated into the water column. Observations on the spatial relationship of the ZC and ZP, analysis of net proton flux, incorporation of photosynthate translocation coupled with an understanding of the importance of boundary layers (BL) leads to a unified hypothesis that describes the processes involved in coral metabolism. The proposed model is based on the observation that reef corals have evolved a wide range of morphologies, but all of them place the ZC between the ZP and the external seawater. This spatial arrangement places the BL in contact with the ZC in order to facilitate efflux of protons out of the corallum. Placement of the ZC between the ZP and the BL maximizes recycling of the metabolic products O2 and HCO3−. Furthermore, this arrangement maximizes the photosynthetic efficiency of zooxanthellae by producing a canopy structure with the skeletal material in the ZC serving to absorb ultraviolet radiation (UVR) while scattering photosynthetically active radiation (PAR) in a manner that maximizes absorption by the zooxanthellae. The ZP is isolated from the water column by the ZC and the BL. Therefore ZP must exchange metabolic materials with the ZC and with the water column through the ZC and its overlying BL. The resulting configuration is highly efficient and responsive to irradiance direction, irradiance intensity, water motion and coral polyp morphology. The skeletons of corals are thereby passively modified in response to physical factors such as light and water motion regime. The model presents a unified theory of coral metabolism and provides explanations for many paradoxes of coral biology, including plasticity of the diverse growth forms and an explanation for coral skeletal growth response to ocean acidification.
Continue reading ‘The reef coral two compartment proton flux model: a new approach relating tissue-level physiological processes to gross corallum morphology’
Published 27 October 2011
Jobs , Science
The Lamont-Doherty Earth Observatory of Columbia University invites applications for a full-time post-doctoral research scientist position in the field of paleoceanography. The successful candidate will join a dynamic and interdisciplinary group of scientists working on a wide range of interrelated problems examining Earth’s past climate history, ocean chemistry and circulation, ice sheet stability, sea level, and the interactions of the solid Earth, ocean, and cryosphere. The positions are full-time 1-year appointments, with the opportunity for continuation and growth depending on progress and availability of funding.
We seek qualified, highly motivated candidates for the following research activities:
Foraminifer shell geochemistry/paleoceanographer. The successful candidate will work on one of several potential research areas including coretop calibrations of planktonic foraminifera and pteropods with oceanic carbon chemistry and physical parameters, Pliocene changes in the composition and ventilation of upper ocean waters, and high-resolution records of Holocene SST variability. The candidate will have experience with species identification, stable isotope geochemistry and analysis, and trace element analyses using ICP-MS (mid-2012 delivery).
Continue reading ‘Post-doctoral research scientist in paleoceanography’