Friday November 16, 2018

Here’s Why Man-made Pesticides Affect Marine Animals More

The study calls for monitoring our waterways to learn more about the impact of pesticides and agricultural run-off on marine mammals.

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Marine animals are more vulnerable to man-made pesticides. Flickr
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Marine mammals such as dolphins, manatees, seals and whales, which evolved to make water their primary habitat, lost the ability to make a gene that defends humans and other land-dwelling mammals from the neurotoxic effects of a popular human-made pesticide, a new study has revealed.

The researchers found that the marine mammals lost the gene Paraoxonase 1 (PON1) that effectively defends humans and other terrestrial mammals from organophosphates — a group of man-made insecticides.

PON1 potentially reduces cellular damage caused by unstable oxygen atoms and also protects us from organophosphates that kills by disrupting neurological systems.

Whales and dolphins lost the gene PON1 soon after they split from their common ancestor with hippopotamuses 53 million years ago; manatees lost it after their split from their common ancestor with elephants 64 million years ago.

Marine life
Whales and dolphins lost the gene PON1. VOA

But some seals likely lost PON1 function more recently, at most 21 million years ago and possibly in very recent times.

“The big question is, why did they lose function at PON1 in the first place? It’s hard to tell whether it was no longer necessary or whether it was preventing them from adapting to a marine environment,” said lead author Wynn K. Meyer, postdoctoral associate at the University of Pittsburgh in the US.

“We know that ancient marine environments didn’t have organophosphate pesticides, so we think the loss might instead be related to PON1’s role in responding to the extreme oxidative stress generated by long periods of diving and rapid resurfacing,” Meyer added.

For the study, appearing in the journal Science, the team analysed DNA sequences from five species of marine mammals and 53 species of terrestrial mammals and reacted their blood samples with an organophosphate by-product.

 Marine Mammals lost the ability that defends humans and other land-dwelling mammals from the neurotoxic effects of a popular human-made pesticide.
Marine Animals lost the ability that defends humans and other land-dwelling mammals from the neurotoxic effects of a popular human-made pesticide.

The blood did not break down the organophosphate by-product the way it did in land mammals, indicating that unless a different biological mechanism is protecting the marine mammals, they would be susceptible to organophosphate poisoning — a form of poisoning that results from the build-up of chemical signals in the body, especially the brain.

Also Read: European Countries Bans Bee-Killing Pesticides

The study calls for monitoring our waterways to learn more about the impact of pesticides and agricultural run-off on marine mammals.(IANS)

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The Ocean And Its Climate Crisis

Globally, fishing is a $140 billion to $150 billion business annually

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Oceans, boats
Lobster boats are moored in the harbor in Stonington, Maine. VOA

To stand at the edge of an ocean is to face an eternity of waves and water, a shroud covering seven-tenths of the Earth.

Hidden below are mountain ranges and canyons that rival anything on land. There you will find the Earth’s largest habitat, home to billions of plants and animals — the vast majority of the living things on the planet.

In this little-seen world, swirling super-highway currents move warm water thousands of miles north and south from the tropics to cooler latitudes, while cold water pumps from the poles to warmer climes.

Ocean
Artisanal fishing boats moored in the harbor at Nouadhibou, the main port in Mauritania. VOA

It is a system that we take for granted as much as we do the circulation of our own blood. It substantially regulates the Earth’s temperature, and it has been mitigating the recent spike in atmospheric temperatures, soaking up much of human-generated heat and carbon dioxide. Without these ocean gyres to moderate temperatures, the Earth would be uninhabitable.

In the last few decades, however, the oceans have undergone unprecedented warming. Currents have shifted. These changes are for the most part invisible from land, but this hidden climate change has had a disturbing impact on marine life — in effect, creating an epic underwater refugee crisis.

Reuters has discovered that from the waters off the East Coast of the United States to the coasts of West Africa, marine creatures are fleeing for their lives, and the communities that depend on them are facing disruption as a result.

ocean, fish, sardines
A fisherman unloads sardines at the port in Matosinhos, Portugal. VOA

As waters warm, fish and other sea life are migrating poleward, seeking to maintain the even temperatures they need to thrive and breed. The number of creatures involved in this massive diaspora may well dwarf any climate impacts yet seen on land.

In the U.S. North Atlantic, for example, fisheries data show that in recent years, at least 85 percent of the nearly 70 federally tracked species have shifted north or deeper, or both, when compared to the norm over the past half-century. And the most dramatic of species shifts have occurred in the last 10 or 15 years.

Fish have always followed changing conditions, sometimes with devastating effects for people, as the starvation that beset Norwegian fishing villages in past centuries when the herring failed to appear one season will attest. But what is happening today is different: The accelerating rise in sea temperatures, which scientists primarily attribute to the burning of fossil fuels, is causing a lasting shift in fisheries.

The changes below the surface are not an academic matter.

Ocean, lobster
Lindsay Copeland Frazier holds lobsters caught on her father’s boat in Stonington, Maine. VOA

Globally, fishing is a $140 billion to $150 billion business annually, according to the United Nations’ Food and Agriculture Organization, and in some parts of the world, seafood accounts for half of the average person’s diet. But the effects of this mass migration in the world’s ocean are also much more intimate than that.

From lobstermen in Maine to fishermen in North Carolina, livelihoods are at stake. For sardine-eating Portuguese and seafood-loving Japanese, cultural heritages are at risk. And a burgeoning aquaculture industry, fueled in part by the effects of climate change, is decimating traditional fishing in West Africa and destroying coastal mangrove swamps in Southeast Asia.

Also Read: 60 percent Wildlife Lost In Just Four Decades: Report

Reuters journalists have spent more than a year collecting their stories and little-reported data to bring you this series revealing the natural disaster unfolding beneath the whitecaps. (VOA)