Aug 2015

Ocean Acidification

By Mike Waddington

Pumping greenhouse gasses into the atmosphere does not only causing global warming and change the climate, it is also causing significant damage to our oceans too. The oceans absorb carbon dioxide (CO2) from the atmosphere, but since the dawn of the industrial revolution, the oceans have been absorbing more and more of the excess CO2. At first, scientists thought this may be a good thing, as the oceans were removing much of the greenhouse gasses in the atmosphere, however more recently studies have discovered that this excess CO2 is changing the oceans chemistry. This is commonly known as “Ocean Acidification” and it is bad news for everything that lives in the oceans.

Carbon dioxide is acidic, which means when it is dissolved into salt water, it causes the water to become more acidic. The pH of something is measure on a scale from 1 to 14, with the lower the number, the more acidic it is. Since the industrial revolution, the pH of the oceans has dropped from 8.2 to 8.1, which may not sound like a lot, but almost everything living in the oceans is incredibly delicate. Like the Richter scale, the pH scale is logarithmic, which means this 0.1 drop means that the acidity of the oceans has increased by around 30%! The oceans have had a stable pH level for millions of years, but now suddenly rising acidity levels are already causing damage to marine organisms that cannot adapt fast enough to keep up with the change. Estimations of future carbon dioxide levels predict that if we continue down the path we are already on, the oceans could be nearly 150% more acidic than they already are by the end of the century.


Ocean acidification is expected to impact a wide variety of species, either directly or indirectly. For instance, sea grasses and algae are much like terrestrial plants, they photosynthesize, which means they could benefit from the higher levels of carbon dioxide in the water. Unfortunately, they are the only organisms that could really benefit. The higher acidity in the water will cause serious problems for any organism that requires the process of calcification to grow.

Zooplankton are at the bottom of the ladder for almost every marine food web. These microscopic creatures are considered the most important creatures in the sea. They also have shells that are made of calcium carbonate, which dissolves rapidly in more acidic conditions. They reproduce rapidly, so they might possibly be able to adapt faster than larger animals. However, if they cannot adapt, most life in the oceans would cease to exist, as almost all marine food webs would collapse.

Shellfish, such as clams, oysters, and scallops etc. rely on calcium carbonate to build their shells. The specific type of calcium carbonate their shells are made of dissolves very easily under more acidic conditions, which causes their shells to become thinner and their growth rate to slow. Molluscs form another important level of the ocean food web, and their numbers are dropping. This drop is not just effecting the marine life though, the U.S. shellfish industry is worth hundreds of millions of dollars, and employs tens of thousands of people. In the Pacific Northwest, ocean acidification has already caused massive oyster die-offs, severely damaging oyster populations.



Hard corals build their exoskeleton from calcium carbonate and soft corals have small amount of calcium carbonate in their internal structure to help keep themselves upright. Ocean acidification is causing the growth rate of coral to slow, and is even causing already existing structures to erode. Many studies are showing that some reefs are eroding faster than they are growing, which is deeply concerning scientists around the world. Coral reefs support 25% of all marine life, and millions of people around the world rely on them for food and coastal protection.


Many scientists believe that ocean acidification is one of the biggest threats (if not the biggest) to our oceans today. Despite international awareness of carbon dioxide related issues, the amount we are pumping into the atmosphere is continuing to rise. However, despite the rapidly changing environment, we are also seeing some marine creatures showing incredible resilience. Some species can adapt, but not overnight. The best thing we can do it to try and cut our own carbon emissions. By supporting renewable energies; such as solar or wind power, using public transportation, using energy saving bulbs, or simple keeping our car tyres properly inflated, we can reduce our own emissions. It is only recently that ocean acidification has been fully studied and seen as a real threat, so many people are still completely unaware of its existence. Spreading awareness and educating others is the key to making this issue a top priority. If everyone understood what was happening to one of our most important resources, then maybe we could all band together to help make a change.


‘Ocean Acidification’ was written by Mike

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Mike Waddington

I first discovered diving in 2008 after going snorkeling on the Great Barrier Reef in Australia. After trying diving at a flooded quarry in England I decided to head out to warmer more interesting waters in Thailand where I ended on the Island of Koh Tao completing my Open Water course. Instantly addicted with money to spend and plenty of time on my hands I decided to continue until I became a Divemaster so I could live what seemed as the perfect life.

After that I headed to the Caribbean to an island called Utila to complete my instructor course, I spent several months out there completing the MSDT internship, teaching students and leading dives. This is also where I discovered my interest in the technical side of diving, taking part in equipment repair courses and learning about blending gasses and running compressors.

With all my new qualifications it was time to head back to where it had all started, Back to Koh Tao where I intended on living the dream. Once I arrived I quickly found a job and started teaching straight away. During my time on Koh Tao I took part in all many technical diving courses, learning how to dive with re-breathers, in caves and even going down to 90m/300ft!


PADI Master Scuba Diver Trainer
PADI/DSAT Tech Deep Instructor
PADI/DSAT Gas Trimix Gas Blender
PADI/DSAT Trimix Diver
TDI Intro to Cave Diver
TDI Advanced Wreck Diver
TDI Inspiration rebreather Decompression Procedures
PADI Professional Videographer
BSAC Compressor Operator
TDI Equipment Service Technician

Dream Dive Locations:

Silfra, Iceland
Cenotes, Mexico
Chuuk Lagoon, Micronesia
Ice Diving in Russia