ocean acidification

Ocean Acidification And Mass Extinction

November 26, 2019 By EarthWise Leave a Comment

Since the industrial revolution, the concentration of carbon dioxide in the atmosphere has increased due to the burning of fossil fuels and land use changes. The ocean absorbs about 30% of the CO2 that is released in the atmosphere. As the levels of atmospheric CO2 increase, so do the levels in the ocean.

When CO2 is absorbed by the ocean, a series of chemical reactions occur, resulting in seawater becoming more acidic. Ocean acidification threatens calcifying organisms, such as clams and corals, as well as other marine animals, like fish. When these organisms are at risk, the entire marine ecosystem may also be at risk.

In fact, according to research recently published in the journal Proceedings of the National Academy of Sciences, fossil evidence from 66 million years ago has revealed that ocean acidification can cause the mass extinction of marine life. Researchers analyzed seashells in sediment laid down shortly after a giant meteorite hit earth. This strike wiped out the dinosaurs and 75% of marine species. Chemical analysis of the shells revealed a sharp drop in the PH of the ocean over hundreds of years after the meteorite strike. The meteorite impact vaporized rocks, causing carbonic acid and sulphuric acid to rain down, acidifying the ocean. The strike also resulted in mass die-off of plants on land, increasing atmospheric CO2.

Researchers found that the pH dropped by 0.25 pH units in the 100 to 1,000 years after the meteorite strike. Alarmingly, scientists expect the pH of the ocean to drop by 0.4 pH units by 2100 if our carbon emissions continue as projected.

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Ocean acidification can cause mass extinctions, fossils reveal

Photo, posted March 16, 2017, courtesy of Zachary Martin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Pesticides In The Great Barrier Reef

November 7, 2019 By EarthWise Leave a Comment

Australia’s Great Barrier Reef is one of the greatest natural wonders in the world and it has been under siege by warming waters and ocean acidification. Widespread coral bleaching has damaged or destroyed large portions of the 1,400-mile long coral reef system. But the effects of climate change are not the only threat to the reef. Pesticides found in waterways that flow into the Great Barrier Reef are another serious problem.

According to a new study by the University of Queensland, the combined toxicity of 22 of the most common pesticides that flow into the Reef are not meeting pollution reduction targets.

Different pesticides affect different organisms. Herbicides affect organisms that photosynthesize such as seagrass, corals, mangroves, and algae. Insecticides affect insect larvae in freshwater, and crustaceans such as crabs, prawns, and lobsters. Previous assessments have only examined individual pesticides and only for limited times. The new study has utilized a methodology that estimates the combined toxicity of multiple pesticides found in the waterways that discharge into the Reef and does it for the entire wet season.

The research revealed that the pesticide reduction target set in the Australian Government’s Reef 2050 Water Quality Improvement Plan is not being met. Only one natural resource management region – the Cape York region – was found to be meeting its target.

By having estimates of the risk posed by pesticides in the various regions and individual waterways, governments, farmers, and conservationists can see which areas pose the greatest risk and where to maximize efforts. Stakeholders have to come together to reduce pesticide concentrations through better management practices and by using less toxic pesticides.

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High pesticide concentrations continue to enter Great Barrier Reef

Photo, posted July 29, 2010, courtesy of Kyle Taylor via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Vulnerable Shorelines

May 21, 2019 By EarthWise Leave a Comment

Global climate change is having noticeable effects on the environment. For example, glaciers are shrinking. Plant and animal ranges are shifting and populations decreasing. And droughts, floods, and wildfires are becoming more frequent and more intense. According to the Intergovernmental Panel on Climate Change, the evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time.

Our coastal shorelines, which are already stressed by human activity, pollution, storms, and invasive species, are one of many areas expected to be further threatened by climate change. Sea level rise and more intense and frequent storms are expected to erode and inundate coastal ecosystems and eliminate wetlands. Ocean acidification is also projected to disrupt marine environments.

But according to scientists at the Massachusetts Institute of Technology, seagrasses could play a key role in protecting these vulnerable shorelines from this onslaught. The MIT research team demonstrated how the ubiquitous marine plants dissipate wave energy and help protect against erosion, which could help mitigate damage from rising seas.

Using mathematical modelling and experiments, the MIT researchers were able to quantify for the first time how large and dense a continuous meadow of seagrass must be in order to provide adequate damping of waves in a given setting. They also found that seagrasses offer significant environmental benefits, including preventing beach erosion, protecting seawalls and coastal structures, improving water quality, and sequestering carbon.

Submerged aquatic vegetation, including seagrasses, provides an ecosystem service exceeding $4 trillion annually. Hopefully these findings can help provide useful guidance for seagrass restoration efforts.

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Seagrass’ strong potential for curbing erosion

The Effects of Climate Change

Photo, posted October 13, 2010, courtesy of the NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Infertility

March 8, 2019 By EarthWise Leave a Comment

Many of us are all too familiar with the effects of climate change. Our changing climate, as a result of our actions, is leading to rising global temperatures, biodiversity loss, ocean acidification, wildfires, more weather extremes like floods and droughts. But a lesser known effect of climate change could lead to frightening consequences: infertility.

According to researchers at the University of Liverpool, rising temperatures could make some species sterile and lead them to succumb to the effects of climate change far earlier than currently thought. Their work was recently published in the journal Trends in Ecology and Evolution, and it was produced in collaboration with scientists from the University of Leeds, University of Melbourne, and Stockholm University.

Biologists and conservationists are trying to predict where species will be lost due to climate change so that suitable reserves can be established in other locations. But the problem is that most data on when temperature will make an area unlivable for a species is based on its ‘critical thermal limit’ or CTL. This is the temperature at which a species would collapse, stop moving, or die.

The authors of the article fear that the impact of climate change on species survival is being underestimated. Because rather than zeroing in on lethal temperatures, the scientists argue the focus should be on the temperatures at which organisms can no longer breed. Extensive plant and animal data suggest organisms lose fertility at a lower temperature than their CTL.

The scientists have proposed a new fertility-based metric to gauge how organisms function as temperatures climb: Thermal Fertility Limit or TFL. Understanding when a species will cease to reproduce will certainly help conservation measures.

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Climate change and infertility — a ticking time bomb?

Photo, posted August 11, 2013, courtesy of Mike Lewinski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Hawaii

December 18, 2017 By EarthWise Leave a Comment

The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and seamounts in the North Pacific Ocean. The islands are a world-renowned vacation spot, known for their white-sand beaches, lush flora, and near perfect weather. But stormier days may be ahead.

Looking For “Super Coral”

November 2, 2017 By EarthWise Leave a Comment

Coral reefs are essential for much of marine life and are the basis of many commercial fisheries. In places from Florida to Australia, they are major tourist attractions. Estimates are that the economic impact of coral reefs is more than $375 billion a year. And apart from all of that, they are some of the most beautiful places on the planet.

Storing Carbon in the Ocean

October 6, 2017 By EarthWise Leave a Comment

As carbon dioxide levels in the atmosphere continue to rise, it may be that clean energy technologies, electric cars, and other methods of reducing emissions may not be enough. Carbon sequestration – sucking carbon out of the atmosphere – is seen by many as a crucial part of the solution.

An Electric, Autonomous Container Ship

September 18, 2017 By EarthWise Leave a Comment

Electric cars are big news these days and so are self-driving cars. But now there is about to be an electric, self-navigating cargo ship. The soon-to-be-finished ship is called the Yara Birkeland, and is being built under a partnership between two Norwegian companies.

Threats To Coral Reefs

May 12, 2017 By EarthWise

There has been much news recently about the growing bleaching events going on in the world’s coral reefs associated with ocean warming and acidification. The massive damage to Australia’s Great Barrier Reef is an ongoing tragedy.

Restorative Ocean Farming

November 16, 2016 By WAMC WEB

The conventional aquaculture industry has often been associated with many of the same problems that beset land-based agriculture: creating sterile monocultures, fouling the environment with pesticides, antibiotics and organic pollutants, and spreading diseases.

Breeding Super Corals

October 19, 2015 By EarthWise

The world’s coral reefs are increasingly threatened by the changing climate. Both warmer ocean temperatures and increasing ocean acidification are damaging coral populations and endangering the very existence of coral reefs.