Climate Change

This is the findings of a new study in Global Change Biology by the University of British Columbia. The reason for this future decline in size stems from the fact that fish are cold-blooded animals, and are thus unable to regulate their body temperatures.

“When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said co-author William Cheung, associate professor at the Institute for the Ocean and Fisheries and director of science for the Nippon Foundation-UBC Nereus Program.

Antioxidant capacity is a critical component of stress tolerance because in a range of organisms, including corals, stressors such as high water temperature, poor water quality and even pathogen infection, produce an increase in damaging, highly reactive oxygen molecules (free radicals) inside the tissues.

The ability to tolerate environmental stress varies between individuals, so the team associated with the Australian Institute of Marine Science set out to find the most stress-tolerant of the common reef-building coral Acropora millepora.

With up to 10m tides, the Kimberley region in north Western Australia has the largest tropical tides in the world, creating naturally extreme and highly dynamic coastal habitats that corals from more typical reefs could not survive.

Researchers at the University of Western Australia's Oceans Institute were thus surprised to find that corals from the region are just as sensitive to heat stress and bleaching as their counterparts from less extreme environments elsewhere.

Corals depend on symbiotic algae to survive and build coral reefs. Increased ocean temperatures due to climate change can cause these symbiotic algae to be expelled from the coral, an event known as bleaching, which often leads to death.

Scientists from University of Miami placed corals in tanks and subjected them to increased water temperatures to gain insights into how they may react to global warming by replicating ocean conditions that would lead to both mild and severe coral bleaching.

According to a new study from the University of British Columbia, the worst-case scenario—in which ocean temperatures rise by as much as 3 degrees Celsius by 2100—showed fish could move as far as 16 miles per decade away from the equator.

The study also predict, based on projections from multiple models, that egg and hatchling survival will drop by half in the next 100 years as a result of global climate change.

When leatherback turtle hatchlings dig out of their nests buried in the sandy Playa Grande beach in northwest Costa Rica, they enter a world filled with dangers. This critically endangered species faces threats that include egg poaching and human fishing practices.