Hard core data shows 14 per cent drop in coral growth on GBR since 1990

It’s official: the biggest and most robust corals on the Great Barrier Reef (GBR) have slowed their growth by more than 14 per cent since the “tipping point” year of 1990. Evidence is strong that the decline has been caused by a synergistic combination of rising sea surface temperatures and ocean acidification.

Electrochemical Splitting of Calcium Carbonate to Increase Solution Alkalinity: Implications for Mitigation of Carbon Dioxide and Ocean Acidity

Electrochemical splitting of calcium carbonate (e.g., as contained in limestone or other minerals) is explored as a means of forming dissolve hydroxides for absorbing, neutralizing, and storing carbon dioxide, and for restoring, preserving, or enhancing ocean calcification. While essentially insoluble in water, CaCO₃ can be dissolved in the presence of the highly acidic anolyte of a water electrolysis cell. The resulting charged constituents, Ca²⁺ and CO₃²⁻, migrate to the cathode and anode, respectively, forming Ca(OH)₂ on the one hand and H₂CO₃ (or H₂O and CO₂) on the other. By maintaining a pH between 6 and 9, subsequent hydroxide reactions with CO₂ primarily produce dissolved calcium bicarbonate, Ca(HCO₃)_2aq. Thus, for each mole of CaCO₃ split, there can be a net capture of up to 1 mol of CO₂. Ca(HCO₃)_2aq is thus the carbon sequestrant that can be diluted and stored in the ocean, in natural or artificial surface water reservoirs, or underground. The theoretical work requirement for the reaction is 266 kJ_e per net mole CO₂ consumed. Even with inefficiencies, a realized net energy expenditure lower than the preceding quantity appears possible considering energy recovery via oxidation of the H₂ produced. The net process cost is estimated to be <$100/tonne CO₂ mitigated. An experimental demonstration of the concept is presented, and further implementation issues are discussed.

Barrier Reef coral growth ‘will stop’

Scientists fear the already declining growth rate of the Great Barrier Reef’s corals will stop completely by 2050, killing off the reef and making way for algae.

A new report shows the most robust corals on the reef have slowed in growth by more than 14 per cent since the “tipping point” in 1990.

The paper, published in the international journal Science and written by scientists Dr Glenn De’ath, Dr Janice Lough and Dr Katharina Fabricius, shows evidence of a decline in the calcification rates in the Great Barrier Reef corals.

The Australian Institute of Science paper claims the decline has been caused by a combination of rising sea surface temperatures and ocean acidification.