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Ocean Health and Ill-health!

Ocean Health
dead fish in plastic glove

So far we have described our carbon footprint on land, but we must be mindful that the Earth is also know as the “Blue Planet”.

It is important to understand the crucial role between oceans and human health and the enormous opportunity we have, as healthcare professionals and healthcare organisations, to move towards a more sustainable future in which oceans and water systems are not left behind.

The ocean is the largest interconnected ecosystem on the planet. 

  • It contains 97% of the earth’s water
  • It covers 71% earth’s surface
  • It produces 50% of oxygen
  • It provides 99% of living space
  • It stores 40 trillion tonnes carbon
  • It is home to 80% of living organisms
  • It absorbs 90% of the planet’s excess heat
  • It absorbs 25% of our anthropogenic CO2
“Human health is inextricably linked to the oceans and waterways and the use of aquatic environments as a waste sink is associated with numerous adverse health impacts which must not be ignored by healthcare systems and policymakers”

———Dr Richard Hixson and Dr Georgie Sowman, co-founders of Healthcare Ocean

When the ocean is overwhelmed with too much CO2. its photosynthetic capacity becomes overwhelmed and it acidifies. Rather than being removed through ocean plant photosynthesis, the CO2 dissolves in the water and acidifies. 

Currently we are seeing a very fast rate of acidification, and oceanic pH has dropped by 0.13 units over the last 170 years. This is a 30% rise in hydrogen ion concentration. This level of acidification has not been seen for millions of years! 

Why is ocean acidification a problem?

An acidic environment dissolves the protective calcium carbonate skeletons that make up many of the marine species, such as molluscs, corals and some varieties of plankton.

  • The shells and skeletons of these animals may become less dense or strong and they experience changes in growth, development, abundance and survival.
  • In the case of coral reefs, this may make them more vulnerable to storm damage and slow the recovery rate.

Ocean acidification is incredibly serious!

Acidification along with warming (marine heatwaves) and anoxia in the oceans is creating a toxic triad of conditions that is destroying vast areas of the oceans’ ecosystems.

These effects are rippling through all marine species right down to the smallest photosynthesis organisms, phytoplankton. These organisms are hugely important as they are ultimately responsible for the O2 we breath, the food we eat and the CO2 absorbed.


  • Produce O2through photosynthesis
  • Support most marine food webs and fishery production. Phytoplankton are the foundation of the aquatic food web. They are the primary producers, feeding everything from microscopic, animal-like zooplankton to multi-ton whales.
  • They consume CO2, acting as part of the biological carbon pump

“By absorbing carbon, phytoplankton are our greatest ally in combating climate change”

—————— David Attenborough 2021

What is at risk?

  • Food security
  • Loss of livelihoods
  • Physical health – 250 million cases of gastroenteritis and respiratory disease are linked annually to swimming in contaminated seas. Harmful algae blooms produce neurological and hepatic toxins, and extreme weather can result in drownings.
  • Mental health and well-being
  • Supply chains and economic growth. More unstable oceans, with water storm fronts can lead to problems with supply chains
  • Discovery of new medicines
  • Carbon sequestration 
  • Climate regulation, for example by the slowing of the Gulf Stream and other big ocean currents, such as the North Equatorial Current

How can healthcare drive the change?

  • Through shipping: Ships produce a gigaton of CO2 every year, and a lot of non-carbon harms as well. We (healthcare) have great buying power to leverage change in our suppliers and in the shipping industry.
  • Prevent chemical contamination: Pharmaceutical chemicals are contaminating global waterways threatening environmental and human health. They are contributing to biodiversity loss and driving antimicrobial resistance.
  • Plastics: Plastic is everywhere. Plastic is not biodegradable, it is indestructible. Current estimates suggest that all the plastic waste in the ocean, if laid end to end, would stretch 18, 640miles (30,000km), the distance from New York City, USA to Sydney, Australia.

Continue onto the next steps to find out more about how healthcare contributes to chemical contamination of our waterways, antimicrobial resistance and plastic waste.


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