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Dec 17, 2022 · A person can survive for hours or even days after being immersed in water and still be alive, depending on how deep the water was, how long the person was underwater, and other factors. However, there is a consensus that someone can die from drowning within minutes of submerging.
Mar 1, 2016 · Rigor mortis and livor mortis are typically present in bodies recovered from the water though the onset and waning of these classic postmortem changes may be altered by water temperature, current, changing of body position due to movement, and level of activity prior to death.
- James L. Caruso
- 10.23907/2016.003
- 2016
- Acad Forensic Pathol. 2016 Mar; 6(1): 19-27.
How long does it take for a body to decompose at sea? - BBC Science Focus Magazine.
Jan 14, 2022 · As oceans warm, their heat supercharges weather systems, creating more powerful storms and hurricanes, and more intense rainfall. That threatens human lives and livelihoods as well as marine life.
- Overview
- A global snapshot
- The big picture
- What can be done?
The ocean feels heat waves just like the ones on land, and underwater life is struggling to survive them.
Intense heat waves are bad for human health. They can lead to sometimes deadly conditions like dehydration and stroke. And just like extreme temperatures on land, marine heat waves can drastically alter life under the sea.
A new study published today in Nature Climate Change found that the occurrences of marine heat waves have substantially grown in the past three decades, and it’s becoming clearer how deadly warmer temperatures are for biodiversity.
Marine heat waves are periods when the average water temperature of a given region is exceptionally high. In the past 30 years marine heat wave days have increased by just over 54 percent, a trend the study’s authors found consistent with declines in oceans life.
High-profile marine heat waves like “the blob,” a huge mass of warm water that was present off the U.S. West Coast from 2014-2016, were included in the study. The blob was responsible for massive die-offs of everything from invertebrates to marine mammals.
“It is clear that extreme warming events can drive abrupt changes in entire ecosystems with widespread consequences,” says study author ecologist Daniel Smale.
To get a global snapshot of how marine heat waves are changing life in the world's oceans, Smale and his research team looked at 116 previously published papers. It gave them data from over 1,000 different ecological records. Heat waves were quantified as any period longer than five days when the ocean warmed to abnormally high temperatures.
They then used existing datasets to quantify the amount of biodiversity in a given region. Particularly worrying to the scientists were regions with dense biodiversity that experienced warming. Those regions were especially at risk of life being damaged or dying off and having cascading effects on neighboring ecosystems.
Three regions were particularly hard hit by warming waters, the study notes: coral reefs in the Caribbean, seagrass in Australia, and kelp forests off the coast of California.
Warming disrupts the typical functions of such massive ecological habitats. Corals, for instance, become stressed when subjected to warmer-than-average temperatures. They then expel their symbiotic algae and undergo a process called coral bleaching where the normally colorful coral becomes sickly and turns a stark white.
In 2005, the U.S. lost half of its Caribbean corals. On the Great Barrier Reef, more than half of the region's corals are already dead. When corals die, they can no longer support the hundreds of fish and other marine species that live on the reefs.
“Coral reefs that evolved with just a few weeks of above-average temperatures every decade or so are now suffering up to three months of extreme temperature every few years,” says ecologist Enric Sala, a National Geographic explorer who was not involved with the study.
“For example, tropical storms will create even more destruction because coral reefs won't be able to continue growing and protecting the shores from waves,” he says.
Shrinking biodiversity may also one day have profound impacts on food security and sea-based economies. Last week, a study published in the journal Science found that climate change is causing fish to disappear. Global populations of fish taken for human consumption by fisheries have decreased by around 4 percent. For some regions that experience warming waters as well as overfishing, the decline is more than 30 percent.
“Ocean systems are facing a number of threats, such as plastic pollution and ocean acidification,” says Smale. “But it is clear that extreme warming events can drive abrupt changes in entire ecosystems with widespread consequences.”
He predicts that warming events will continue to threaten the balance of ocean life in the coming decades.
“The ultimate cause is something we have to address,” says Katie Matthews, the deputy chief scientist at Oceana. “If we don’t do that, everything else we work on will have little to no impact.”
She adds that climate-conscious fishery management and monitoring ocean warming in real time are tools that can help minimize impacts from warming events in the meantime.
Mar 7, 2018 · A significant number of water-related deaths are attributed to accidental drowning, while a smaller but still significant number represent suicidal or homicidal drowning. Others involve a combination of drowning precipitated by injury, intoxication, or environmental extremes.
Dec 31, 2017 · However, various factors contribute to the rate of cooling and death as a result of cold water immersion including cold shock, physical incapacitation leading to swimming cessation, drowning, hypothermia and dehydration.
