Ocean acidification takes sperm back in time

Ocean acidification as a result of an enriched carbon dioxide atmosphere threatens ecosystem health and marine biodiversity. The reproductive and early life-stages of animals have been suggested as among the most vulnerable to ocean acidification perturbations. To explore this theory further we applied computer assisted sperm analysis (CASA) to investigate the combined effect of pH (8.06–7.67) and temperature (14–20°C) on sea urchin sperm motility. Previous studies have either observed no or inhibitory impacts of ocean acidification on sperm swimming. Surprisingly, we observed a substantial improvement in swimming speed at reduced seawater pH compared with performance at current pH levels. This suggests that current levels may be suboptimal for maximal sperm swimming speeds. Temperature was found to affect swimming speed but not percent motility. Our observations suggest that swimming speed may be improved as seawater pH approaches conditions resembling the paleo-ocean. However, this does not necessarily equate to an improvement in reproductive fitness due to a trade-off between sperm-swimming speed and longevity. This indicates that ocean acidification may benefit certain aspects of the reproductive biology of some marine animals.

Triple trouble – Ocean acidification, warming and deoxygenation

As huge amounts of financial investments are put into mitigating the effects of climate change on forests and renewable energy projects, marine scientists feel the oceans are being neglected by governments and policymakers.

As much as the land is affected by the climate change conditions, oceans are affected by acidification, warming and deoygenation which are all detrimental to the marine ecosystem. Climate change influences oxygen levels in the oceans with a particularly harsh effect on the warmer waters as higher temperatures reduce oxygen solubility. Ocean acidification and nutrient run-off from streams and rivers can contribute to deoxygenation. These effects combine resulting in interconnected triple trouble for the oceans.

Oceans ‘ignored’ on COP17 agenda

Durban – The world’s oceans, often referred to as the heart and lungs of the planet, are under stress and scientists are calling for immediate action.

“Often forgotten in such discussions are the oceans and the enormous and diverse resources they provide, including food and other resources,” said Dr Carol Turley from Plymouth Marine Laboratory in the UK.

Turley, speaking during a side event at COP17, said this was the most ignored ecosystem at COP17. Also, the potential for undiscovered biodiversity was too great to be sidelined.

In a world where food security was already under threat due to climate change, scientists feel it would be worth exploring the ocean for new sources of food.

The oceans cover nearly three quarters of the earth’s surface and contain 96 percent of its living space. Oceans also provide around half of the oxygen and are becoming an increasingly relied upon source of protein for a rapidly growing population. Almost a billion people rely on protein from marine life.

But Turley said three stressors – ocean acidification, warming and deoxygenation – are producing a very worrying combination which is threatening the oceans.