But like many coastal species they have been chronically overfished.
One remote community in Madagascar has started a pioneering coastal-farming project with astonishing results.
The ocean is facing environmental catastrophe.
Overfishing is a ticking time bomb for both planet and people.
In one remote coastal village the locals appear to have found an unlikely solution.
A strange little sea creature that’s a popular aphrodisiac and just possibly a fisherman’s salvation.
In the first business of its kind in Madagascar, Dadiny has recently started farming these animals.
Sea cucumbers.
Sea cucumbers are under threat.
Growing them in designated and contained areas is helping to protect both this important species and other kinds of marine life here in the south-west of Madagascar.
Because of the part sea cucumbers play in cleaning up the seabed it’s believed that they help maintain stocks of other marine life.
In this region, not just sea cucumbers, but all kinds of marine life have suffered from chronic overfishing.
When marine conservationist Alasdair Harris first visited Madagascar in 2001 he was shocked to discover the extent of this devastation.
To reduce this overfishing the NGO that Alasdair runs helped train 700 local fishermen and women in small-scale sustainable sea-cucumber farming.
It’s meant many locals are no longer using the techniques that contributed to overfishing in this region. Alasdair’s research suggests fish stocks have doubled here since 2006.
But it is not marine conservation that has fundamentally persuaded the local population to buy in to aquaculture - It’s hard economics.
There’s a strong demand for sea cucumbers in Asia where they’re prized as an aphrodisiac.
Farmers here can now make up to $50 a month, about twice that of a regular fisherman.
While this is still substantially below the average global wage, it’s brought dramatic improvements in the local quality of life.
NGOs, including Alasdair’s, are now working on similar farming ventures in other coastal villages around Madagascar.
Localised efforts can only go so far in countering the vast damage to ecosystems across the ocean.
But in the face of an increasingly urgent crisis that could still be a very long way.
While ordinary vegetable cucumbers cost $3 per kilo, sea cucumbers can cost over $3,000 per kilo.
These animals are prized as a delicacy in Asia, and are used by pharmaceutical companies to treat diseases like cancer.
Unfortunately, over-harvesting now threatens many sea cucumber populations
The eating behavior of some sea cucumber is definitely stunning
Throughout his lifetime, Ivan Constantinovich Aivazovsky contributed over 6,000 paintings to the art world, ranging from his early landscapes of the Crimean countryside to the seascapes and coastal scenes for which he is most famous.
Aivazovsky was especially effective at developing the play of light in his paintings, sometimes applying layers of color to create a transparent quality, a technique for which they are highly admired. Although he produced many portraits and landscapes, over half of all of Aivazovsky’s paintings are realistic depictions of coastal scenes and seascapes.
He is most remembered for his beautifully melodramatic renditions of the seascapes of which he painted the most.
Many of his later works depict the painful heartbreak of soldiers at battle or lost at sea, with a soft celestial body taunting of hope from behind the clouds.
His artistic technique centers on his ability to render the realistic shimmer of the water against the light of the subject in the painting, be it the full moon, the sunrise, or battleships in flames.
Many of his paintings also illustrate his adeptness at filling the sky with light, be it the diffuse light of a full moon through fog, or the orange glow of the sun gleaming through the clouds. In addition to being the most prolific of Russian Armenian painters, Aivazovsky founded an art school and gallery to engage and educate other artists of the day.
He also and built a historical museum in his hometown on Feodosia, Crimea, in addition to beginning the first archaeological expeditions of the same region.
Planktonic foraminifera assemblage from Caribbean sediments that
provide an accurate picture of the species community before human
influence.
Each shell is less than one millimeter in size. A clever study finds that communities of foraminifera, a hard-shelled kind of plankton, have transformed dramatically since the Industrial Revolution.
As scientists scramble to figure out how warming ocean temperatures will affect marine ecosystems across the globe—from bleaching coral reefs to altered migration routes—one of the sea’s most ubiquitous organisms is helping researchers measure the changes that have already occurred.
Centuries of fossil records and live-capture data show that some marine plankton populations reflect a clear change in response to human industrialization and the warming oceans that have come with it.
Researchers found distinct differences between communities of planktonic foraminifera—tiny single-celled creatures that float in ocean waters—from before and after the start of the industrial era about 170 years ago, according to a study published this week in Nature.
The ratio of plankton species in these communities shifted in proportion to changes in sea temperature, indicating that ocean warming has deeply altered these populations and their wider marine ecosystems.
Microscopic view on marine plankton.
Credit: A. Stuhr, GEOMAR.
While the idea that climate change affects marine life isn’t new, the plankton study incorporates an unusually complete data set that spans the globe and cuts deep into past centuries to reaffirm humanity’s impact on the oceans.
Planktonic foraminifera provide a comprehensive fossil record because their hard calcite shells are preserved well in sediment layers at the bottom of the ocean, says lead author Lukas Jonkers, a paleontological oceanographer at the University of Bremen in Germany.
The organisms also populate waters all across the world.
Though rare in the surface ocean, planktonic foraminifera are abundant at greater depths, and in some places they carpet entire swaths of the sea floor, Jonkers says.
Recovery of a sediment trap on board the research vessel Meteor in the tropical North Atlantic Ocean. Such sediment traps provide information on modern planktonic foraminifera species communities, which were found to be systematically different from pre-industrial communities from sediments.
(Christiane Schmidt)
“We can really compare very well the distribution of the species in the modern [era] with the past,” Jonkers says.
“There's not so many zooplankton groups where the fossil records are so well preserved.
In fact, I don't think there's any.”
To understand the state of these communities before the industrial era kicked off, Jonkers and his team analyzed more than 3,700 previously collected samples from sediment layers on the bottom of the ocean.
Based on how fast sediment accumulates and mixes on the seafloor, scientists estimated that the top layer of sediment cores—basically “cylinders of mud” pulled up from the bottom of the ocean—would contain fossils that are couple of centuries old, Jonkers says, predating the industrial revolution.
The team then compared these pre-industrial samples with more recent data collected using sediment traps, which are funnels moored to the seafloor that grab anything falling down from the ocean’s upper layers (including the plankton that drift through the water).
Using information collected from 1978 to 2013, researchers discovered that planktonic foraminifera communities changed markedly during the time period between the deposit of the seafloor fossils and the organisms caught in sediment traps.
The shift, measured by comparing the relative abundances of dozens of plankton species within the samples, doesn’t appear to be random.
The amount of change in the plankton communities correlated with the degree of documented temperature change in the surrounding waters.
The direction of shifting communities also largely lined up with patterns of ocean temperature change, as authors found when they matched up seafloor fossils with their closest analogues in modern communities.
With the data showing a match in both the degree and the direction of change, Jonkers says he’s confident that temperature is the driving force for the shifts in planktonic foraminifera populations.
“I was expecting to see a difference and an effect of global change,” Jonkers says.
“But I hadn't expected that the signal would be so clear.”
The distribution of modern-day (white dots) and ancient (grey dots) zooplankton data used in the study. Sea surface temperature change from 1870 to 2015 is also shown.
Source: Jonkers et al. (2019)
Illustration of phytoplankton species distribution across the global ocean.
Credit: Jorge Martinez-Rey and Meike Vogt, 2019/ Damiano Righetti, 2019
The new study replicates on a global scale what other researchers have found in specific areas, says David Field, a marine scientist at Hawaii Pacific University who has researched planktonic foraminifera but was not involved in this study.
While scientists have yet to fully unravel why exactly plankton communities are changing, the evidence from this study and others clearly points to ocean warming as the likely cause, either as a direct influence or as an indirect driver of other aspects of the underwater environment, Field says.
Comparing sediment-trap samples to seafloor fossils might not be a perfect analogy—differences in preservation could be a possible influence on the data—but Field says the authors’ evidence provides compelling support for the huge influence of ocean warming on marine species.
“This indicates that warming began to have an effect on marine ecosystems a long time ago, even before we were keeping good records on it,” Field says.
“We can expect much more impact of ocean warming on ecosystems in the future.
Oceans are going to continue to change in ways we haven’t seen before.”
Planktonic foraminifera may not be as majestic as whales or sea stars, but the breadth of their fossil record provides a useful baseline to confirm a wider trend of ocean life changing in response to human activity.
Shifts in plankton communities are a concerning indicator of the “bigger picture” for marine ecosystems as ocean temperatures continue to rise at increasing rates, Jonkers says.“The question is, what will happen with climate change progressing?” Jonkers says.
“Even at one degree [of temperature change], we already see large changes in planktonic foraminifera, and probably also in other marine biota.
That means that all these species have to adapt, and at the moment, we don't know if they can, or if they can do so fast enough.
Sea War Museum Jutland in Thyborøn has made a new sensational discovery during its continued registration of shipwrecks in the North Sea and Skagerrak.
In April 2018, the museum found the wreck of the German submarine U-3523, which was sunk with depth charges in Skagerrak by a British B24-Liberator aircraft on May 6, 1945.
Just the day before, the German forces in Denmark, Northwest Germany and Holland had surrendered, so the submarine was not engaged in battle, but was probably on its way to Norway.
The U-3523 was of the new and highly advanced type XXI that could have revolutionized the submarine war if enough boats had been completed in due time.
118 boats were in the process of being build, but only two came into active service, and none was ever engaged in battle.
U-3523 appeared on the survey screen during the museum's scan of the seabed some ten miles north of Skagen, and the discovery was very surprising.
Very unusually, the entire submarine bow is buried in the seabed while the stern is approximately 20 meters above the sea bottom.
The wreck lies at 123 metres of water depth, making it very difficult to access.
The collapsing Nazi government ordered all U-boats in German ports to make their way to their bases in Norway on May 2, 1945.
Two days later, the recently commissioned U-3523 joined the mission as one of the most advanced boats in the fleet.
But to reach their destination, the submarines had to pass through the bottleneck of the Skagerrak – the strait between Norway and Denmark – and the UK’s Royal Air Force was waiting for them. Several U-boats were sunk and U-3523 was destroyed in an air attack by a Liberator bomber.
geolocalisation with the GeoGarage platform (DGA nautical chart)
The submarine, called U-3523, was recently discovered by the Sea War Museum Jutland over 10 Nm north of Skagen (Denmark's northernmost town) and 9 Nm West of the position reported by originally, at a depth of 123m.
U-3523 lay undiscovered on the seabed for over 70 years until it was recently located by surveyors from the Sea War Museum in Denmark.
Studying the vessel will be of immense interest to professional and amateur historians alike, not least as a way of finally putting to rest the conspiracy theory that the boat was ferrying prominent Nazis to Argentina.
But sadly, recovering U-3523 is not a realistic proposition.
The main challenges with such wrecks lie in accurately identifying them, assessing their status as naval graves and protecting them for the future.
U-boat wrecks like these from the end of World War II are the hardest to match to historical records.
The otherwise meticulous record keeping of the Kriegsmarine (Nazi navy) became progressively sparser, breaking down completely in the last few weeks of the war.
But Allied records have helped determine that this newly discovered wreck is indeed U-3523.
The sea where this U-boat was located was heavily targeted by the RAF because it knew newly-built boats would flee to Norway this way.
Identification
The detailed sonar scans of the wreck site show that it is without doubt a Type XXI U-boat, of which U-3523 was the only one lost in the Skagerrak and unaccounted for.
These were new types of submarines that contained a number of innovations which had the potential to make them dangerous opponents.
This was primarily due to enlarged batteries, coupled to a snorkel, which meant they could stay permanently underwater.
Part of the RAF’s mission was to prevent any of these new vessels getting to sea to sink Allied ships, and it successfully prevented any Type XXI U-boats from doing so.
With the U-boat’s identity correctly established, we now know that it is the grave site of its crew of 58 German servicemen.
As such, the wreck should either be left in peace or, more implausibly, recovered and the men buried on land.
Germany lost over 800 submarines at sea during the two world wars and many have been found in recent years.
It is hopelessly impractical to recover them all, so leaving them where they are is the only real option.
Under international law all naval wrecks are termed “sovereign immune”, which means they will always be the property of the German state despite lying in Danish waters.
But Denmark has a duty to protect the wreck, especially if Germany asks it to do so.
Protection
Hundreds of wartime wreck sites such as U-3523 are under threat around the world from metal thieves and grave robbers.
The British cruiser HMS Exeter, which was sunk in the Java Sea on May 1, 1942, has been entirely removed from the seabed for scrap.
And wrecks from the 1916 Battle of Jutland that also lie partly in Danish waters have seen industrial levels of metal theft.
These examples serve as a warning that organised criminals will target shipwrecks of any age for the metals they contain.
Detailed sonar scans have been taken.
Sea War Museum
Germany and the UK are among a number of countries currently pioneering the use of satellite monitoring to detect suspicious activity on shipwrecks thought to be under threat.
This kind of monitoring could be a cost-effective way to save underwater cultural heritage from criminal activity and its use is likely to become widespread in the next few years.
Recovery
The recovery cost is only a small fraction of the funds needed to preserve and display an iron object that has been immersed in the sea for many years.
So bringing a wreck back to the surface should not be undertaken lightly.
In nearly all cases of salvaged U-boats, the results have been financially ruinous.
Lifting barges that can raise shipwrecks using large cranes cost tens of thousands of pounds a day to charter.
Once recovered, the costs of conservation and presentation mount astronomically as the boat will rapidly start to rust.
The U-boat U-534 was also sunk by the RAF in 1945, close to where U-3523 now lies.
Its crew all evacuated that boat, meaning that she was not a grave when recovered from the sea in 1993 by Danish businessman Karsten Ree, allegedly in the somewhat incredible belief that it carried Nazi treasure.
At a reported cost of £3m, the operation is thought to have been unprofitable.
The boat contained nothing special, just the usual mundane objects carried on a U-boat at war.
U-534 was salvaged in 1993 and since February 2009 has been on display in Birkenhead, England as part of the U-boat Story.
The U-boat is one of only four German World War II submarines in preserved condition remaining in the world.
A Royal Air Force bomber sank her on 5 May 1945 in the Kattegat 20 kilometres northeast of the Danish island of Anholt.
Similar problems were experienced by the Royal Navy Submarine Museum in the UK when it raised the Holland 1 submarine in 1982.
In that case, the costs of long-term preservationproved much greater than anticipated after the initial rust-prevention treatment failed to stop the boat corroding.
It had to be placed in a sealed tank full of alkali sodium carbonate solution for four years until the corrosive chloride ions had been removed, and was then transferred to a purpose-built exhibition building to protect it further.
The expensive process of raising more sunken submarines will add little to our knowledge of life at sea during World War II.
But each time a U-boat is found, it places one more jigsaw piece in its correct place, giving us a clearer picture of the history of the U-boat wars.
This is the true purpose of archaeology.
By combining 25 years of ESA satellite data, scientists have discovered that warming ocean waters have caused the ice to thin so rapidly that 24% of the glacier ice in West Antarctica is now affected.
A paper published in Geophysical Research Letters describes how the UK Centre for Polar Observation and Modelling (CPOM) used over 800 million measurements of Antarctic ice sheet height recorded by radar altimeter instruments on ESA’s ERS-1, ERS-2, Envisat and CryoSat satellite missions between 1992 and 2017.
The study also used simulations of snowfall over the same period produced by the RACMO regional climate model.
Together, these measurements allow changes in ice-sheet height to be separated into those caused by meteorological events, which affect snow, and those caused by longer-term changes in climate, which affect ice.
The ice sheet has thinned by up to 122 metres in places, with the most rapid changes occurring in West Antarctica where ocean melting has triggered glacier imbalance.
CPOM Director, Andy Shepherd, explained, “Parts of Antarctica have thinned by extraordinary amounts. So we set out to show how much was down to changes in climate and how much was instead due to weather.”
3D view of Thwaites Glacier’s grounding line migration over 500 years,
for old models (green) where the bedrock is rigid, and our new model
(red) where the bedrock is elastic.
Note that the ice shelf (floating
part of the glacier) has been masked to show the underlying bedrock.
Credit: Eric Larour @JPL/NASA/CalTech
To do this, the team compared measurements of surface-height change with the simulated changes in snowfall.
Where the signal was greater they attributed its origin to glacier imbalance.
They found that fluctuations in snowfall tend to drive small changes in height over large areas for a few years at a time, whereas the most pronounced changes in ice thickness coincide with signals of glacier imbalance that have persisted for decades.
Prof. Shepherd added, “Knowing how much snow has fallen has really helped us to isolate the glacier imbalance within the satellite record.
We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet.
Twaites glacier with the GeoGarage platform (NGA nautical chart)
“After 25 years, the pattern of glacier thinning has spread across 24% of West Antarctica, and its largest ice streams – the Pine Island and Thwaites Glaciers – are now losing ice five times faster than they were in the 1990s.
“Altogether, ice losses from East and West Antarctica have added 4.6 mm of water to global sea level since 1992.”
ESA’s Marcus Engdahl, noted, “This is a fantastic demonstration of how satellite missions can help us to understand how our planet is changing.
The polar regions are hostile environments and are extremely difficult to access from the ground.
Because of this, the view from space is an essential tool for tracking the effects of climate change.”
Scientific results such as this are key to understanding how our planet works and how natural processes are being affected by climate change – and ice is a hot topic at ESA’s Living Planet Symposium, which is currently in full swing in Milan.
This study demonstrates that the changing climate is causing real changes in the far reaches of the Antarctic.
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