PhD Code: MARES_11_19:
Mobility
- Host institute 1: P12 - Pavia University
- Host institute 2: P7 - University of Plymouth
- T1 - Future Oceans: temperature changes - hypoxia - acidifation
- Chiara Lombardi
- Piero Calosi
Subject description
Since the start of the industrial revolution atmospheric CO2 concentrations have risen from 280 to 380 ppm causing an increase in global temperature and a drop in the oceanic pH [1]. The rise in atmospheric CO2 concentrations is predicted to continue, reaching 750-1000ppm CO2 by the year 2100, this causing a further increase in sea surface temperature (approximately 5°C) and a further decrease in pH (0.3). Decreased ocean pH and elevated temperature are serious threat to marine biodiversity of marine ecosystems [2] causing changes in ocean chemistry and, as consequence, on species abundance, distribution, and development. However, filled and laboratory experiments revealed that species may show different levels of vulnerability to Global Changes, indicating there may be a complex response to ocean acidification (OA) and global warming (GW) due to indirect ecological effects [3].
Organisms secreting calcareous skeletons which create permanent carbonate structures, complex in physical architecture and associated biota, representing a key for promoting marine biodiversity [4], are particularly vulnerable to OA [5] since calcium carbonate skeletons are potentially susceptible to dissolution in acidic waters. In addition, the imbalance of extracellular fluid acid-base status and consequent disruption of energetic metabolism can potentially make calcification more challenging. The degree of susceptibility of species with calcium carbonate skeletons is dependent not only on pH and carbonate saturation, but also on the crystalline form of calcium carbonate used and the amount of magnesium in solid solution: the mineral aragonite is twice as soluble as calcite, and high-Mg calcite significantly more soluble than low-Mg calcite. Responses to simulated OA have been found to be extremely varied in species with calcium carbonate skeletons tested under laboratory and natural conditions [6,7].
Among calcifiers, almost 26 phyla are able to produce more than 60 different minerals for their own functional requirements. Some of these biogenic minerals are formed on such a large scale in the biosphere that have major impact on ocean chemistry and are important components of marine sediments. Biominerals are composed of inorganic minerals and organic macromolecules (proteins, proteoglycans, lipids and polysaccharides) fundamental in controlling the intricate detail of shell formation, determining nucleation, stabilization and mineral polymorph unutilized [8]. Organic macromolecules also play an active role in the formation of organic tissues that, in most calcifying organisms, separates shell or skeletons from ambient seawater [6]. Integral to organism function, biomineralization is not a simply a passive process but is subject to a high degree of organism control.
Considering the effect of seawater chemistry on calcifiers skeleton, altered environmental conditions induced by elevated [CO2] and temperature is a research priority as ongoing environmental changes will likely affect these organisms and their contribute in carbon cycle, among other ecosystem services they provide. Given the high level of diversity in biomineralization processes and biomineralizers structures, it is likely that different classes of marine calcifiers (coralline algae, corals, molluscs, crustaceans, echinoderms, bryozoans) will respond differently to fast occurring drop in ocean pH and increase is sea surface temperature. Despite some evidences support this idea [6] little is known about different level of vulnerability of different type of calcifiers. However, so far most of global change biology studies have been conducted outside an explicit evolutionary context, these limiting our predictive ability of what biodiversity response to the ongoing change will be.
During the three year project, MARES candidate will investigate the effects of global changes (OA and global warming) at inorganic and organic levels in selected calcifying organisms from Mediterranean Sea and Atlantic Ocean and explore how these calcifying organisms could respond and adapt to altered ocean conditions expected for 2100. In details, the candidate will investigate on-the-field characterisation of taxa calcification responses along natural CO2/temperature gradients (e.g. CO2 volcanic vents) and run laboratory-based natural selection experiment (multigenerational experiments designed to characterise species resilience, plasticity and adaptability of the calcification response to environmental challenges). Being based at the Marine Environment and Sustainable Development Unit of Santa Teresa of La Spezia (ENEA - Italian national Agency for New Technologies, Energy and Sustainable Economic Development, by consulting the Libraries and open-access Journal available at the Institutes (ENEA S. Teresa and University of Pavia), plan, develop and realize the field work using boat and diving facilities at the ENEA, perform some of the analyses using instruments available at the laboratories Santa Teresa (ENEA) and Department of Earth and Environmental Sciences (University of Pavia). The candidate will have the opportunity to work and collaborate with scientists from different disciplines (Oceanography, Physic, Geology, Chemistry) and consult environmental data set available from long monitoring instruments (coastal meteorological station – wind speed and direction, solar radiation, air temperature, humidity, atmospheric pressure and precipitation; shelf sea oceanographic buoy (28 m deep)- seawater temperature, salinity, fluorescence, oxygen, ph profiles; in field temperature sensors). Because of the ongoing collaborations of Marine Environment and Sustainable Development Unit of Santa Teresa with some local Marine Protected Areas (Cinque Terre National Park and Parco Regionale di Portovenere- La Spezia), the candidates will have the opportunity to work also in areas of marine biodiversity protection and conservation. During 6 months at the University of Plymouth, the candidate will use the pCO2 experimental manipulation facility at the Marine Biology and Ecology Research Centre at the University of Plymouth to investigate undertake. Being part of an international context, ENEA, University of Pavia and University of Plymouth regularly host scientists from all over the world, who collaborate in several projects and give seminars/lectures for scientists and students. Also congresses and meetings are often organized and promoted by the three institutes. These scientific exchanges and activities offer opportunities to the candidate to meet expert in several fields, develop collaborations with scientists regularly or occasionally working and visiting the institutes and build the base for her/his future carrier.
References
1 Caldeira K, Wickett ME (2003) Anthropogenic carbon and ocean pH. Nature 425: 365
2 Kleypas JA, Feely RA, Fabry VJ, Langdon C, Sabine CL, Robbins LL (2006) Impact of ocean acidification on coral reefs and other marine calcifiers: a case guide for future research. Report of a workshop held 18–20 April 2005. St. Petersburg, FL, sponsored
3 Pistevos JCA, Calosi P, Widdicombe S, Bishop JDD (2011). Will variation among genetic individuals influence species responses to global climate change? OIKOS 120: 675-689
5 Cocito S (2004) Bioconstruction and biodiversity: their mutual influence. Scientia Marina 68: 137-144
4 Fabry VJ, Seibel BA, Feely RA, Orr JC (2008) Impacts of ocean acidification on marine fauna and ecosystem processes. ICES Journal of Marine Science 65: 414–432
6 Ries J, Cohen AL, McCorkle DC (2009) Marine calcifiers exhibit mixed responses to CO2 induced ocean acdification. GSA, 37 (12): 1131-1134
7 Lombardi C, Rodolfo-Metalpa R, Cocito S, Gambi MC, Taylor PD (2011) Structural and geochemical alterations in the Mg calcite bryozoan Myriapora truncata under elevated seawater pCO2 simulating ocean acidification. Marine Ecology 32:211–2219
8 Dove PM, De Yoreo J, Weiner S (2003) Biomineralization. Ross JJ (ed.), pp. 381
Expected outcomes
At least two scientific publications on peer-reviewed journals, participation to international conferences and meetings (posters/talks), dissemination at Universities and International Reserach Institutes. The candidates will be also involved in educational programmes for schools and encouraged to present her/his own work to the public (seminars, meetings, science 'Open Days') in order to sensitize public awareness of Climate Changes and Marine Biodiversity Loss.