what is ocean acidification

The Implication of Ocean Acidification on Marine Life

There is a forlorn hope that spraying 7 billion tonnes per year of fossil carbon (in the form of carbon dioxide) from the combustion of coal, oil and gas into the atmosphere will have little impact on the chemical structure of the atmosphere and the oceans. Sadly, this is not the case.

Since the industrial revolution, the proportion of carbon dioxide in the atmosphere has increased from 250 ppm to present value of 400 ppm, an increase of 30 percent. By the middle of the 21st century, this is likely to increase to 750 ppm – a ‘tipping point’ being investigated by the European Project on Ocean Acidification (EPOCA).

The GAIA Theory

Professor James Lovelock has put forward the GAIA theory which proposes a linkage and interactivity between oceans, the atmosphere, ice, volcanoes and land masses and their populations.  This linkage is starting to show in the interaction and exchange of gases between the atmosphere and the oceans. Oceanic phytoplankton are responsible for absorbing about 50% of the atmospheric CO2 and releasing some 50% of oxygen being fed into the atmosphere. The absorption of a surfeit of CO2 results in a progressive ‘acidification’ (carbonic acid) of the chemical make-up of the seas.

As a result of the increased atmospheric CO2, the alkalinity of the oceans has dropped from a value of 8.2 to 8.1 over the period since the start of the industrial revolution.  This reduction in alkalinity has resulted in the inhibition of the ‘calcification’ process i.e. the means by which benthic and pelagic sea life and corals create shells and skeletons. The reduction also negatively impacts on the production of limestone and chalk deposits. Whilst the GAIA theory suggests a level of ‘self-regulation’ between interactivity, it does not preclude change.

Phytoplankton and Zooplankton

Phytoplankton are the most important organisms in the marine food chain in that, through a process of photosynthesis, they combine the inorganic elements of seawater, CO2 and sunlight to form the organic ‘vegetable matter’ (including algae) at the base of the marine food chain.  This same photosynthetic process releases the oxygen into the atmosphere.

what is ocean acidification

Zooplankton are equally important to the marine food chain in that they extract calcium from the calcium carbonate dissolved in the oceans. This calcium reinforced protein (and the skeletal remains) forms the basis for the deposition of chalk (coral reefs and the white cliffs of Dover), limestone (the Dolomites and Mendips), the formation of coral reefs (via the coral polyps), the formation and development of shell coverings for lobsters. crabs, scallops and clams and, probably the skeleton formation for such species as the cod and haddock.

Climate Change

The main ‘driver’ in climate change is water vapour (held in the atmosphere in a gaseous invisible form).  The condensation of this water vapour (attaching to hygroscopic nuclei – man-made and naturally-occurring) on this atmospheric dust creates visible cloud droplets which fall to the ground when sufficiently coalesced and heavy enough in the form of rain, sleet or snow. Warm air can hold more water vapour than cold air.

This will mean that a warmer climate will mean less cloud formation, (with its attendant protection from direct sunlight) and a dryer earth’s surface (extending desert areas) – – the water vapour will be held in the atmosphere in the vapour form.

climate change impacts on marine life

Arctic and Antarctic Summer Sea Ice Melt

The importance of plankton to various migratory whales and dolphins is shown by polar summer sea-ice melts. These melts release plankton trapped in the sea ice in trillions. The plankton are taken up by the krill which, in turn, is the food reward for whales and dolphins undertaking the migration.

Why Ocean Acidification is a Problem

The importance of the impacts of ocean acidification cannot be over-stated.  There is very strong scientific evidence (to the point that DEFRA is charging the Plymouth Marine Laboratory and the National Oceanographic Institute with urgent research projects) that the calcification process including shell formation on most of the benthic (sea-bed dwelling) and skeletons on pelagic (surface water) species in UK waters is being inhibited by the acidification.


Does this mean the end of crab sandwiches, lobster thermidor and cod and chips? Only more and very urgent scientific research can answer. The implications for the marine food supplies and the associated industries hinge on the findings of such research.  The fact is that ocean acidification has serious social, economic, diplomatic, political, cultural and industrial implications on a global scale.

It seems likely that by the middle of this century only the more acid-tolerant species of marine life will survive in any healthy state.

Monty Halls Senior
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Originally posted 2015-10-18 14:42:18. Republished by Blog Post Promoter

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