Final Report Summary - BIOCARB (Carbonate Biomineralization in the Marine Environment: Paleo-climate proxies and the origin of vital effects)
The main objective of this ERC project was to develop methods to study the processes involved in the formation of biocarbonates by marine organisms, in order to obtain a better understanding of the cellular level transport processes, the formation timescales and dynamics of biocarbonate ultrastructural components, as well as trace-element and isotopic fractionations. Along the way, we have added the study of metabolic transfer in these same organisms to our project activities because these metabolic processes are closely linked with the biomineralization activity.
The strategy we have pursued is to develop techniques based on a concentration-enrichment of a minor stable isotope of a trace element (e.g. Mg, Sr, or Ca) or a nutrient (e.g. ammonium, nitrate or bicarbonate) that are natural components of seawater, resulting in the formation of biocarbonate or cellular structures with corresponding isotopic enrichments. The biocarbonate or tissue sections are subsequently imaged with secondary and/or transmisions electron microscopy (SEM and TEM, respectively) and then with the NanoSIMS ion microprobe to visualize the locations of the isotopic marker on sub-micrometric length scales, permitting resolution of all ultra-structural details.
We have worked with stable isotopes such as 13C, 15N, 26Mg, 44Ca, and 86Sr. Enhancing the concentration of such isotopes in seawater is likely to inflict a minimum of physiological stress on the organism that could otherwise perturb the biomineralization and metabolic processes we are studying. During the first 30 months of the ERC project, our group has used these stable isotope labeling techniques to obtain information about the dynamics of biocarbonate formation by a number of different organisms, including coral, forminifera, sea-urchin and have made ground breaking progress in the study of coral subcellular metabolism, including assimilation, fixation, remobilization, translocation and utilization of molecules such as ammonium, nitrate and bicarbonate. In the last part of the project we have turned our attention to studying these processes under environmental conditions simulating the effects of global climate change.
The strategy we have pursued is to develop techniques based on a concentration-enrichment of a minor stable isotope of a trace element (e.g. Mg, Sr, or Ca) or a nutrient (e.g. ammonium, nitrate or bicarbonate) that are natural components of seawater, resulting in the formation of biocarbonate or cellular structures with corresponding isotopic enrichments. The biocarbonate or tissue sections are subsequently imaged with secondary and/or transmisions electron microscopy (SEM and TEM, respectively) and then with the NanoSIMS ion microprobe to visualize the locations of the isotopic marker on sub-micrometric length scales, permitting resolution of all ultra-structural details.
We have worked with stable isotopes such as 13C, 15N, 26Mg, 44Ca, and 86Sr. Enhancing the concentration of such isotopes in seawater is likely to inflict a minimum of physiological stress on the organism that could otherwise perturb the biomineralization and metabolic processes we are studying. During the first 30 months of the ERC project, our group has used these stable isotope labeling techniques to obtain information about the dynamics of biocarbonate formation by a number of different organisms, including coral, forminifera, sea-urchin and have made ground breaking progress in the study of coral subcellular metabolism, including assimilation, fixation, remobilization, translocation and utilization of molecules such as ammonium, nitrate and bicarbonate. In the last part of the project we have turned our attention to studying these processes under environmental conditions simulating the effects of global climate change.