Our changing ocean – a global problem
Global climate change is in the news daily. We hear about increased air temperatures, glaciers melting and more extreme weather events. However, there is a silent, unmentioned phenomenon of climate change that is occurring in our oceans every day. Not only are the oceans warning but scientists have recently shown that when we burn oil, coal, or gas we are transforming the fundamental chemistry of the oceans, rapidly making the water more acidic. This is known as ocean acidification.
The process of ocean acidification is surprisingly simple. Carbon dioxide from the burning of fossil fuels accumulates in the atmosphere, where it contributes to global warming. But it also affects our oceans. As carbon dioxide enters the ocean, it reacts with sea water to form carbonic acid. Since the start of the Industrial Revolution about 150 years ago, approximately one-quarter to one-third of all CO2 from fossil fuels—or 500 billion tons— has been absorbed by the seas, increasing the average acidity by 30 percent.
A primary concern about rising ocean acidity is that it reduces the availability of carbonate, a substance used by tens of thousands of marine species to form shells and skeletons. This depletion results in slower growth rates and weaker shells in nearly all species studied. If acidity gets high enough, ocean water becomes corrosive and literally dissolves the organism’s shells.
Work being carried out at Southern Cross University’s National Marine Science Centre (NMSC) is studying the effects of ocean acidification on local marine plants and animals. “New South Wales is a climate change hotspot where the ocean is warming faster than the global average and becoming more acidic due to increased CO2” states Dr. Symon Dworjanyn, researcher at the NMSC. The work being done at the NMSC will help inform resource managers, industry and the community as they plan, prepare for and work to minimise the impacts of climate change on our marine resources.
Rising ocean temperatures due to global climate change will also have an effect on marine plants and animals. Locally, sea temperature monitoring has been undertaken by the Marine Parks Authority (MPA) in the Solitary Islands Marine Park (SIMP) since 2001. Plants and animals have adapted to the variable temperatures in the SIMP, however, they can be impacted by extremes. In 2002 bleached coral were detected in the SIMP following high sea temperatures from the East Australian Current (EAC). Sea temperature patterns, and consequently the composition of marine animal and plants in northern NSW are likely to change. One prediction is that corals exist near their upper thermal tolerance and an increase in temperature (>26.7 oC) is likely to result in coral bleaching. Ongoing sea temperature monitoring is critical to predicting changes that may occur under the influence of climate change, as well as management responses.
Combating acidification and ocean warming requires reducing CO2 emissions and improving the overall health of the oceans. What can you do? We can all play a part in using our resources more efficiently by reusing, reducing and recycling. For more ideas on how you can make a difference click here.
