The world’s oceans are essential for human life. The ocean transports heat from the equator to the South and North poles, regulating our climate and weather patterns; is responsible for global transports (as ocean vessels carry 53% and 38% of U.S. imports and exports, respectively); and holds 97% of our planet’s drinking water.
Additionally, and most importantly, the ocean produces over 50% of the world’s oxygen.
Marine photosynthesizers like seaweed and phytoplankton use carbon dioxide, water, and energy from the sun to produce food for themselves, releasing oxygen into the ocean and then into the atmosphere. Unfortunately, according to UN Environment, greenhouse gases are depriving the planet’s oceans of that oxygen.
“If you think ocean warming, think rising sea levels, deaths of coral reefs, and the ocean acidifying,” said Peter Thomson, the UN Special Envoy for the Ocean. “This will make it harder for ocean-based lifeforms like shellfish to survive in the ocean.”
Plastic has certainly received a lot of attention over the years but the effects of greenhouse gases, such as ground-level ozone and carbon dioxide, need to be addressed, as well. Oceans store around 30% of the planet’s carbon dioxide and 93% of all greenhouse gases.
“This global problem, compared to the issue of plastics pollution, is typically ‘unseen’ but no less important, as it adds further to nutrient pollution from wastewater, agricultural and other industrial runoff that is carried to the marine environment by rivers,” added Christoper Cox, program management officer on marine pollution at UN Environment.
The global market demand for gas increases 2% annually and will overtake the demand for coal by 2030. Greenhouse gases are the main source of global air pollution and include carbon dioxide, nitrous oxide, methane, and sulfur hexafluoride.
More research needs to be done to address these global concerns, and taking a look at ocean history is a necessary first step. According to UPI, sea levels began rising 430 million years ago, leading to significant oxygen level depletion. Scientists from Florida State University found that the sudden drop in oxygen levels triggered a massive marine die-off known as the Ireviken extinction event.
Until recently, the exact causes of the Ireviken extinction event were unknown and unconfirmed.
“The connection between these changes in the carbon cycle and the marine extinction event had always been a mystery,” said Seth Young, assistant professor of earth, ocean, and atmospheric sciences at Florida State University.
The researchers used an innovative isotopic analysis technique to analyze ancient ocean sediments and accurately estimate changing oxygen levels in the Silurian Period oceans. Stable carbon isotopes, stable sulfur isotopes, and iodine geochemical signatures were used to reveal ancient oxygen level activity.
“I think it’s important to see how these events played out all the way from extinction interval through [the] recovery period, how severe they were and their connections to the ancient environment along the way,” added Young. “That could help us figure out what’s in store for our future and how we can potentially mitigate some of the negative outcomes.”
As oxygen levels decrease in the world’s oceans, students, researchers, and scientists are working tirelessly across the globe to find revolutionary solutions. Understanding the history of the world’s oceans and how they reacted to changing oxygen levels is crucial.