How pollution is changing the ocean's chemistry | Triona McGrath

The Importance of Oceans and Ocean Acidification

The Role of Oceans in Our Lives

• Oceans cover two-thirds of the Earth, providing half the oxygen we breathe and moderating climate.

• They are crucial for jobs, medicine, and food supply, contributing 20% of protein for the global population.

Introduction to Ocean Acidification

• Ocean acidification is described as the "evil twin" of climate change, significantly impacting ocean chemistry.

• The oceans have absorbed 25% of all carbon dioxide emissions, altering their chemical balance.

Chemical Changes in Seawater

• Increased carbon dioxide leads to lower seawater pH levels, indicating higher acidity—this process is termed ocean acidification.

• Monitoring has shown a direct correlation between atmospheric CO2 levels and oceanic CO2 concentrations over two decades.

Global Monitoring Efforts

• Data from Hawaii shows rising CO2 levels in both atmosphere and surface waters; similar trends are observed in Ireland.

• Scientists at the Marine Institute and NUI Galway confirm local acidification rates match global observations.

Data Collection Methods

• Samples are collected during winter storms in the North Atlantic using specialized instruments lowered from research vessels.

• Seawater samples are taken from depths up to four kilometers for analysis of various chemical parameters.

Impacts of Ocean Acidification on Marine Life

Current Trends in Ocean Acidity

• Since pre-industrial times, ocean acidity has increased by 26%, with projections suggesting a rise of 170% by century's end if emissions continue unchecked.

• This rate is unprecedented compared to historical events over the last 55 million years.

Effects on Marine Species

• Increased acidity reduces carbonate ion concentration essential for shell-building marine species like crabs, mussels, oysters, and corals.

Case Study: Pteropods

• A pteropod's shell dissolved significantly after just 45 days in water simulating future acidic conditions.

Food Chain Implications

• The decline in shellfish populations could disrupt entire marine food chains affecting species from krill to whales.

Cold-Water Corals

• Irish cold-water corals support rich biodiversity but face threats; projections indicate that by century's end, 70% will be surrounded by corrosive seawater.

Tropical Coral Health

• Healthy tropical corals placed in future acidic conditions show concerning signs that may threaten coral reef structures globally.

The Impact of Ocean Acidification on Coral Reefs

The Current State of Coral Reefs

• After six months, coral has nearly completely dissolved, highlighting the severe impact of ocean acidification.

• Coral reefs are crucial ecosystems, supporting 25% of all marine life in the ocean.

• The statement emphasizes that ocean acidification poses a global threat to marine biodiversity.

Future Concerns and Hope

• The speaker expresses concern for future generations, particularly their own child, regarding the state of oceans as they grow up.

• Acknowledges that excessive carbon dioxide emissions have already been released into the atmosphere, contributing to ongoing acidification.

• Despite the grim outlook, there is a call to action: it is possible to slow down this process and prevent catastrophic outcomes.