Alterations in Ocean Chemistry
The global climate is changing due to human activities. The accumulation of greenhouse gases in the atmosphere has greatly impacted the Earth’s climate system, due to the increase in average global temperatures, leading to alterations in its seas and oceans, thus creating current ocean acidification.
Climate change has caused the oceans to become more acidic, affecting different species and marine ecosystems in complex ways. Ocean acidification, or OA, results from the increasing concentrations of carbon dioxide (CO2) in the water. This is caused by humans emitting more CO2 from their activities into the atmosphere than ever before, making the ocean absorb more CO2.
With increasing atmospheric CO2 concentrations, ocean chemistry is altered and pH levels drop. OA increases ocean water’s acidity and can disrupt shell-building for certain marine organisms. This change in ocean chemistry is a concerning factor for climate change and its effects on marine species and ecosystems.
What is Ocean Acidification?
Ocean acidification refers to the decrease in average oceanic pH values due to increases in atmospheric CO2 concentrations. It is a direct consequence of rising levels of atmospheric carbon dioxide (CO2), which is largely generated by human activities, such as the burning of fossil fuels and deforestation.
The increased uptake of CO2 by the oceans leads to a decrease in its pH, causing the ocean to become more acidic. The higher CO2 concentrations in the oceans cause more chemical reactions to occur and lead to changes in the concentration of minerals, such as calcium carbonate.
In essence, ocean acidification is a form of global warming caused by increasing atmospheric concentrations of CO2, with the long-term effects becoming much more serious than areas affected by changing weather patterns and air temperatures. Since CO2 is blurring the line between air and sea, the impacts of climate change are felt in areas that were previously untouched by air temperatures, such as in the deeper ocean.
Impacts of Ocean Acidification
Ocean acidification has many impacts on marine habitats and organisms. The decreased pH in the water can disrupt the development of certain marine organisms, especially those with calcium-based skeletons or shells, such as corals, pteropods, molluscs, and echinoderms.
Shell growth can be inhibited or delayed, and the metabolic activities of larvae can be altered, both of which can lead to decreased reproductive output, reduced juvenile growth and mortality, decreased survivability of young organisms, and ultimately, population declines.
In addition, ocean acidification can have wide-ranging impacts on the diversity and abundance of both planktonic species, such as krill, that form the base of food webs, and non-planktonic species, such as algae and small invertebrates.
As ocean acidification progresses, communities can become less diverse and fragile, resulting in marine productivity declines, loss of species biodiversity, complex food web interactions, and changes in the structure of marine communities, with potential implications for fisheries.
Impacts on Marine Species
Marine species are particularly vulnerable to the impacts of ocean acidification. OA can cause decrease in ecological functions, including changes in the physical characteristics of oceans.
The decrease in pH can lead to reduced growth and increased mortality of certain marine species, and can also cause behavioural changes in some species. Some species may not be able to adapt to the changing environment and become extinct; while others may be able to adjust and survive.
Furthermore, shifts in the food webs of marine species can occur, and a re-organization of various species may occur as the environment changes, potentially impacting species dependent on each other for food or shelter.
Another direct consequence of ocean acidification is the decreased availability of oxygen, nitrogen and other mineral nutrients, resulting in decreased reproduction rates of species, lower survivability of their young, and recruitment failure of certain species.
Impacts on Marine Ecosystems
Ecosystems are interconnected populations of species that interact with each other and the physical environment in which they live. Ocean acidification, therefore, has the potential to cause changes in marine ecosystems, by altering the relationships between species, reducing their productivity, and introducing new species.
For example, the acidification of ocean surface waters can deplete oxygen and other nutrients, making it difficult for some species to live in and near the surface. This can result in species shifting to deeper waters.
In addition, OA can affect the productivity and composition of plankton communities, which forms the basis of the marine food web and provides an important source of food for larger marine organisms. Furthermore, increased acidity can also lead to changes in seascape structure for organisms living on or within the seafloor.
Consequences for Human Activities
With the increasing impacts of ocean acidification, there are potential consequences for our way of life and activities in the world’s oceans. Loss of species and marine food webs can lead to a decrease in fish stocks and other important marine species, detrimentally impacting fisheries, coastal tourism and other industries dependent on ocean resources.
In addition, an altered ocean chemistry has implications for many aspects of our everyday lives, such as reduced carbon absorption by oceans, and reduced aquaculture productivity.
These consequences, if not addressed, could have serious economic implications, along with negative effects on global food security and human health. Mitigation measures must be taken to try to reduce these consequences, such as reduced CO2 emissions, improved ocean health and better management of marine resources.
Ocean acidification is a serious global problem, whose impacts have the potential to have devastating consequences for the planet. By understanding how ocean acidification works and its impacts, as well as implementing mitigation measures, we can work towards reducing ocean acidification and lessen the impacts of climate change on our planet.
