crabs

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.

A Giant Seaweed Bloom

August 19, 2019 By EarthWise Leave a Comment

Scientists using data from NASA satellites have discovered and documented the largest bloom of seaweed in the world, stretching all the way from West Africa to the Gulf of Mexico. The gigantic macroalgae bloom has been dubbed the Great Atlantic Sargassum Belt.

The brown seaweed floats in surface water and in recent years has become a problem to shorelines lining the tropical Atlantic, Caribbean Sea, Gulf of Mexico, and east coast of Florida. The stuff carpets popular beach destinations and crowded coastal waters. In 2018, more than 20 million tons of it floated on the ocean surface.

Scientists have been studying the Sargassum algae using satellites since 2006, but the major blooms have only started appearing since 2011. They have occurred every year between 2011 and 2018 except for 2013. Before 2011, most of the free-floating Sargassum in the ocean was primarily found in patches around the Gulf of Mexico and the Sargasso Sea located on the western edge of the central Atlantic Ocean.

Sargassum provides habitat for turtles, crabs, fish and birds, and produces oxygen via photosynthesis. However, too much of it can crowd out many marine species.

According to researchers, the ocean’s chemistry must have changed in order for the bloom to get so out of hand. The factors involved include a large seed population left over from a previous bloom, nutrient input from West Africa, and nutrient input from the Amazon River. The increase in nutrients may be a result of deforestation and fertilizer use.

Climate-change effects on precipitation and ocean currents ultimately do play a role in this, but increased ocean temperatures do not. Unfortunately, these giant seaweed blooms are probably here to stay.

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NASA Satellites Find Biggest Seaweed Bloom in the World

Photo courtesy of NASA.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Beaches With Seagrass

February 22, 2019 By EarthWise Leave a Comment

Almost a quarter of the Gross Domestic Product of places around the Caribbean Sea is earned from tourism. Preserving the beaches in the region is an economic imperative. With increasing coastal development, the natural flow of water and sand is disrupted, natural ecosystems are damaged, and many tropical beaches simply disappear into the sea.

With such high stakes, expensive coastal engineering efforts such as repeated replenishing of sand and the construction of concrete protective walls are common strategies. Rising sea levels and increasingly powerful storms only increase the threat to tropical beaches.

Researchers from The Netherlands and Mexico recently published a study in the journal BioScience on the effectiveness of seagrass in holding onto sand and sediment along shorelines.

Seagrasses are so-named because most species have long green, grass-like leaves. They are often confused with seaweeds but are actually more closely related to flowering plants seen on land. Seagrasses have roots, stems and leaves, and produce flowers and seeds. Seagrasses can form dense underwater meadows and are one of the most productive ecosystems in the world. Seagrasses provide shelter and food to an incredibly diverse community of animals, from tiny invertebrates to large fish, crabs, turtles, marine mammals and birds.

The researchers performed measurements of the ability of seagrass along Mexico’s Yucatan Peninsula coastline to keep sand in place and prevent erosion. They found that the amount of erosion was strongly linked to the amount of vegetation. Quite often, seagrass beds have been regarded as a nuisance, rather than a valuable asset for preserving valuable coastlines. The study opens opportunities for developing new tropical beach protection schemes in which ecology is integrated into engineering solutions.

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Seagrass Saves Beaches and Money

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

Earth Wise is a production of WAMC Northeast Public Radio.

Tsunami And Invasive Species

November 13, 2017 By EarthWise Leave a Comment

According to a new study published in the journal Science, scientists have discovered that hundreds of Japanese marine species have been swept across the Pacific Ocean to the United States following the deadly Tsunami in 2011.

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.

Beware The Blob

February 1, 2016 By WAMC WEB

There has been plenty of discussion of El Niño, the periodic weather phenomenon in which prevailing easterly winds in the Pacific Ocean weaken, allowing warm water to move eastward and wreak havoc with the weather in North and South America. The current El Niño is a particularly strong one; some say it may be one of the strongest ever and are calling it the “Godzilla El Niño.”

[Read more…] about Beware The Blob