A major new study has found that fish stocks and other sea life around the globe will be negatively impacted by rising levels of acid in the water caused by carbon dioxide emissions.

The report found that acidification and warming of oceans reduces the survival rates of early life stages of some fish species, reducing the recovery of fish stocks and fishing yields.

It also predicts that the acidification process will lead to the distribution and abundance of fish species changing, impacting economic activities like local fishing and tourism.

The report found that while many organisms can withstand ocean acidification, they lose this ability when exposed to other stressors, like warming, too many nutrients, loss of oxygen or pollution.

90% of the habitable space on the globe is covered in water and the ocean operates as a gigantic sink, taking up a third of the carbon dioxide released into the atmosphere by human activity.

However, as output of CO2 has increased since the industrial revolution, so too have the levels of it in the oceans.

The average pH, a measure of acidity, has dropped from 8.2 to 8.1 at the ocean surface the study found, which on the logarithmic pH scale represents a 30% increase in acidity.

The ocean also absorbs more than 90% of the heat generated by the greenhouse gas effect.

A variety of studies, the researchers say, have found that ocean acidification and warming together affect important services the ocean provides to biological ecosystems and to humans, including regulation of Earth's climate, food provision, recreation and biodiversity.

This latest study confirms many of the findings in relation to the impact on these ecosystems and will be presented to climate change negotiators who meet next month in Bonn, Germany. 

It found that although marine life is able to adapt to ocean change through evolution, the rapid nature of ocean acidification compared to natural processes makes it very difficult for all but organisms with short generation times to keep up.

Around half of the tropical coral reefs can be preserved if CO2 emissions are limited to concentrations that keep the global warming below 1.2 degrees Celsius above pre-industrial levels, but this does not take into account the risk posed by ocean acidification.

The researchers also concluded that acidification reduces the ability of oceans to store carbon, which in theory could have a knock-on impact on the pace of global warming.

The study also discovered that even at the base of the food web small alterations can have knock-on effects for organisms higher up the chain.

The research found that regionally, when stresses such as nutrient runoff or loss of oxygen are reduced, this can reduce the impact of global stressors like ocean acidification or warming.

It also recommends that the precautionary principle be followed in order to reduce or avoid actual or potential future harm.

The research was carried out by 250 members of 20 German institutes representing a broad range of marine science disciplines and was coordinated by GEOMAR Helmholtz Centre for Ocean Research Kiel. 

Together through the Biological Impacts of Ocean Acidification (BIOACID) network, they spent eight years investigating how different marine species responded to ocean acidification, how these reactions impact the food web and marine cycles in the ocean, as well as the consequences for the economy and society.