How are corals doing?
Dr. Walter Dellisanti has worked on answering this for years. Recently, a Marie-Curie grant paved Walter’s way from the heat of Hong Kong to a somewhat different climate at the Marine Biological Section, placed right at the seaside of Øresund in Helsingør. Walter brings a thorough knowledge on coral health to the Department of Biology, where he will apply microenvironmental analysis using microsensors and advanced bioimaging methods to describe the unique microenvironment of corals. Hopefully these studies will increase our understanding of the resilience of corals under global climate changes.
According to Walter Dellisanti
CISME (Community In Situ MEtabolism) device deployment on the surface of the coral Platygyra carnosa. This system allows non invasive measurements of coral metabolic rates.
Credit: Mr. Qingfeng Zhang
Credit: Dr. Alina Szmant
And how is the health of corals assessed?
Walter Dellisanti explains:
“In brief, my idea is to assess the health status of corals using innovative technologies which directly measure metabolic rates on the coral surface. The final aim is to give a comprehensive information on the responses of corals under certain environmental conditions.
In our latest study, I have observed that some corals living in subtropical areas are able to modulate their metabolism (i.e., adapt) according to seawater temperature, salinity, and pH, within certain limits.
For the first time, I have showed that their health and growth are affected by high temperatures in the summer, but the conditions in the spring (transitional conditions) are optimal to stimulate their growth”.
Overall, this research demonstrates that the metabolic plasticity of P. carnosa in response to shifts in seawater quality allows this species to survive ongoing environmental change. Our in-situ observations provide fundamental insights into coral response mechanisms under changing environmental conditions and contribute to projections of coral health under future scenarios of global change”.
Facts on corals Corals create energy to sustain their metabolic processes, such as growth and reproduction, from the symbiosis with microalgae (zooxanthellae) and through feeding on suspended microorganisms. The health and functioning of corals are linked to stable seawater conditions, in particular temperature. Usually tropical corals undergo stress when the water temperature exceeds 30 °C and ultimately they can lose the symbiotic relationship with zooxanthellae. While corals seem to respond to changes in the environment, the entire marine ecosystem is suffering from the challenges deriving from climate change. Researchers aim at characterizing the multiple impacts of human activities, such as direct use of marine resources, pollution, and overfishing. Coral reefs house the greatest biodiversity on Earth, providing food and shelter for a quarter of all animal species in the sea. They also form an important basis of life for more than half a billion people worldwide as an important source for fisheries and the reef formations protect tropical coasts and islands from storms and floods.
Until now, empirical data on coral responses to environmental variables has been limited due to the complexity of underwater methodology used in scientific studies.
"Innovative technologies can now be used in non-disruptive underwater studies to measure metabolic rates and decipher the health conditions of corals. For the first time, we have demonstrated that the metabolism of corals varies with seasonal changes in water quality”, says Walter Dellisanti.
The interesting findings regarding the plasticity of some coral species pave the way of new research aiming at investigating the potential of marine species that are highly resistant to environmental changes for future ecological restoration projects.
From the tropics to Europe, Walter aims now to apply his research ideas on the metabolic performance of Mediterranean corals. A new bio-topic under the spotlight for the importance of understanding continuous environmental changes in the Mediterranean Sea.
This may prove especially important in the future due to various climate change scenarios and emphasizes the broader applicability of coral research.
Walter Dellisanti’s latest
work was published in: