Commentary: The ocean is changing – it’s getting more acidic

WASHINGTON: Ocean acidification, a change in the ocean’s chemistry, is increasingly posing a threat to ocean health.

While this change may be invisible, its effects are not. It is creating conditions that threaten a range of marine species and ecosystems, and thus the economies of coastal communities. All life on earth would eventually be affected as an increasingly warm and acidic ocean produces less oxygen.

There is therefore an urgent need to build resilience against ocean acidification to protect the marine biodiversity on which we depend on for food, development and recreation.


The ocean, which historically had a background pH of 8.2 has grown 25 per cent more acidic over the last two centuries.
The growth of carbon emissions since the Industrial Revolution has been directly tied to this trend known as ocean acidification. Carbon dioxide emitted into the atmosphere is absorbed by the ocean, increasing its acidity level.

Ocean acidification threatens the economic, social, and cultural health of all nations that depend on healthy fisheries, coral reefs, kelp forests, and coastal tourism. It also poses a risk to ecosystem integrity, food security, trade and commerce, tourism and infrastructure, and other human needs.

Ocean acidification is expected to globally cost US$1 trillion per year in financial losses stemming from food web disturbances, mortality of commercially valuable species, loss of coastal protection provided by coral reefs, and the disruption of other ecosystem services by the year 2100.

Most ocean life evolved within a relatively narrow band of variations in ocean temperature, chemistry and depth. As the ocean becomes more acidic, a number of marine species and processes are affected.
Shellfish, corals, snails and other species that rely on calcium carbonate to build their shells are unable to build these structures and may even begin to dissolve.
The shellfish industry in the US Pacific Northwest has had to implement strategies to reduce the significant mortality of juvenile shellfish.

Of greater concern globally, ocean acidification causes deformities and mortality in sea butterflies (pteropods), the small creatures that form the basis of the whole food web in the ocean. Even a relatively small regional loss of pteropods affects all marine life.

Ocean acidification has also been shown to alter fish behaviour and cause mortality at early life stages in fish.

Some reef, and fin fish, such as the pacific salmon, are observed to be unable to differentiate between prey and predator chemical signals, causing them to swim towards rather than away from danger.


Let us be clear that the effects of ocean acidification can only be truly mitigated by reducing greenhouse gas emissions, reducing polluted runoff from the land, and restoring both global fisheries and the supporting coastal habitats such as mangroves, seagrass meadows, and coastal marshes – all of which is costly even if they provide huge benefits.

But we cannot take action without fully understanding how and where ocean chemistry is changing. Change in ocean chemistry differs geographically, temporally and seasonally. Ocean pH also varies regionally and locally.

We need to begin with knowing how to monitor, monitoring, and sharing that data in standardised ways to understand regional and global trends. From there, data can be analysed and used to inform a response.

Understanding ocean acidification at a global scale is still relatively new.
A Global Ocean Acidification Observing Network established in 2012 has helped to establish a common set of standards for the global scientific community’s monitoring and sharing of data, even as it educated and engaged the community in understanding the potential effects of ocean acidification.

It has grown since to a network of over 500 scientists from 83 countries as of 2018, to support and expand the capacity of scientists and their home countries to address the challenges presented by ocean acidification.

The Ocean Foundation (TOF), in partnership with the Global Ocean Acidification Observing Network and many others, established the International Ocean Acidification Initiative to further one goal listed in the United Nations’ Sustainable Development Goals that calls on countries to “conserve and sustainably use the oceans, seas and marine resources for sustainable development”.

More specifically, the foundation is focusing on a target to minimise and address the effects of ocean acidification through enhanced scientific and policy response cooperation at all levels.

Mark J Spalding, Channel News Asia, 21 January 2019. Full Article.

1 Response to “Commentary: The ocean is changing – it’s getting more acidic”

  1. 1 marinelebrec 31 January 2019 at 11:29

    Note that the terminology used in this article is misleading. The definition of “acidic” in the Oxford English dictionary is “having the properties of an acid; having a pH of less than 7″. Despite the process of ocean acidification, the oceans are alkaline (pH higher than 7) and will not become acidic in the foreseeable future. Hence, “acid” or “acidic” should not be used when referring to seawater. Note that there are few exceptions, seawater can be acidic in the immediate vicinity of CO2 vents or in purposeful perturbation experiments

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