Prof. Emeritus Zvy Dubinsky of the Mina and Everard Goodman Faculty of Life Sciencesstudies the response of the photosynthetic apparatus of microalgae to the intensity and spectral composition of underwater irradiance and nutrient concentration.
Dubinsky and his team focus on three systems – Phytoplankton in the Red Sea, the Mediterranean and Lake Kinneret; Zooxanthellae living as endosymbionts in reef building corals; and algal mass cultures for the production of biodiesel and fine chemicals.
They also study bio-optical coupling of the primary productivity of phytoplankton to the underwater light via satellite. Dubinsky’s group has recently developed a novel system for the study of the efficiency of phytoplankton photosynthesis based on photoacoustics.
Dubinsky is currently collaborating with colleagues in Italy on a 5-year, € 3,300,000 EU funded study entitled “Corals and Global Warming: the Mediterranean versus the Red Sea (“CoralWarm”).
The primary goal of the project is to create a model which will enable scientists to foresee how Mediterranean and tropical coral reefs will change over the next 50-100 years, following temperature and acidity increase, as forecasted by the Intergovernmental Panel on Climate Change (IPCC).
Dubinsky’s team is collecting data about Mediterranean and Red Sea key coral species and their response to current temperature and pH gradients.
The temperature gradient is obtained from stations along the Italian shores, extending from the north all the way to the southernmost island of Pantellaria. In order to obtain data on acidity effects, they have been studying underwater corals and other marine organisms at 30m depth, and at various distances from the crater of an extinct, sunken volcano at the Liparian island of Panarea.
The degassing volcano emits CO2 bubbles, creating a pH gradient. All the data and samples collected from the stations are being analyzed according to chemical, molecular, physiological and morphological aspects. Additional data will be collected from corals studied in a series of computerized temperature and pH controlled marine aquaria being built at Bar-Ilan University.
The data is expected to shed light on how coral populations are likely to change in relation to global warming and oceanic acidification.
CoralWarm will generate the first projections of temperate and subtropical coral survival by integrating the effects of sublethal temperature increase on metabolic and skeletal processes in Mediterranean and Red Sea key species.
The project will correlate molecular events to environmental processes, from the nano- to the macro-scale. It aims to reveal new pathways linking environmental factors to final phenotypes, potentially improving prediction and paleo-climatological interpretation.
Field transplantations and controlled experiments are being conducted under various IPCC scenarios. Corals will be grown in aquaria, exposing the Mediterranean species, which are indigenous to cooler waters, to higher temperatures. Red Sea corals will be exposed to gradually increasing temperatures, above those found in the Gulf of Elat (Aqaba).
Expected results include responses of algal symbionts’ photosynthesis, host, symbiont and holobiont respiration, biomineralization rates and patterns – including colony architecture – and reproduction under temperature and pH gradients and combinations.
Molecular aspects of symbiont clades replacement as well as changes in skeletal crystallography will be integrated with biochemical and physiological aspects of temperature response. This analysis is expected to produce a novel mechanistic model for predicting changes in coral ecology and survival.
High-temperature tolerant clades and species will be identified, facilitating future bio-remediation actions and establishment of coral refuges to preserve corals and coral reefs for future generations.