Over the past century the ocean has been rapidly changing
Global water temperatures have increased...
...sea levels have risen...
...and the fundamental chemistry of the ocean has been altered
The biodiversity that appeared on this Earth...
...three and a half billion years ago...
...now are facing threat because of we the humans
A marine biologist in the Bay of Bengal...
...is investigating the resilience of marine life...
...by researching one of the planet’s greatest survivors...
...the horseshoe crab
They’ve outlived the dinosaurs and survived mass extinctions
Can their ability to adapt provide clues for how other ocean creatures...
...might evolve and survive in the face of modern-day climate change
We believe that because the horseshoe crabs have survived...
...they hold the information for survival
In the north-eastern part of the Indian Ocean is the Bay of Bengal
Dr Punyasloke Bhadury and his team of marine biologists...
...are searching for horseshoe crabs
But finding these creatures is harder than it once was
Seems to be an interesting place...
...where we should be able to see some horseshoe crabs
Horseshoe crabs are an example of living fossils
They’ve existed, nearly unchanged, since at least 445m years ago...
...long before dinosaurs
They are a keystone species...
...which means they play a crucial role in maintaining the health...
...of this coastal area
Horseshoe crabs, in sizeable numbers...
...can help accelerate many of the ecosystem-level processes...
...transfer of energy, maintaining the food web...
...ensuring the carbon cycling
So, therefore, they are very, very critical
But they are now on the threatened species list
Ten years ago when I started my work...
...looking at the horseshoe-crab population at this place...
...I would find a lot of horseshoe crabs
Today, I see hardly any horseshoe crabs
The team is researching what is causing the decline in population...
...to help build a case to make part of this coastline a marine-protected area
We are liaising with fisherfolk communities
They get hold of the horseshoe crabs, which are caught in nets or in trawlers
They pass those horseshoe crabs to us so that they can recover
They can help towards the conservation by keeping an eye...
...how the habitat is changing or how they are being threatened
But the team is facing many challenges
Horseshoe crabs are sought after...
...because of their ability to improve human health
They have a unique substance in their blood...
...which is used to make a chemical called limulus amoebocyte lysate
This chemical can detect trace amounts of bacterial contamination
It is used in many vaccines and to test equipment before surgical operations 
As a result, the blood of horseshoe crabs...
...is one of the most valuable liquids on Earth...
...and can be worth as much as $16,000 per litre
Although they are returned to the ocean after being bled...
...an estimated 50,000 horseshoe crabs die in the process per year
But this isn’t the only threat they are facing
Like so many other ocean creatures...
...the horseshoe crabs are also being affected by overfishing...
...coastal pollution and habitat loss
Perhaps the greatest threat, however, comes from climate change
Over the past few hundred years...
...human activity has increased the concentration...
...of carbon dioxide in the atmosphere
This traps heat, most of which is absorbed by the ocean causing it to warm...
...in 2019 its mean surface temperatures were 0.77 degrees Celsius warmer...
...than during the 20th century
And in turn the sea levels have risen
The ocean also absorbs carbon dioxide from the atmosphere...
...changing its chemistry
These factors are affecting ocean species
Many will need to adapt or face the threat of extinction
Today, the researchers are taking water samples and sediment...
...from the bay to analyse back in the lab
What they find on expeditions like this...
...can shape their understanding of the effects of climate change...
...on marine life, like the horseshoe crab
We analyse different environmental parameters...
...to understand the health of this ecosystem...
...for example, charismatic species such as the horseshoe crabs
We can then start to link and understand...
...what kind of changes might be happening to them
The samples are analysed for acidity, temperature and microscopic algae...
...food for many sea creatures, including the horseshoe crab
Using this information the researchers are able to build...
...a more accurate picture of the biodiversity in the area...
...and ultimately which creatures are likely to survive 
This isn’t the first time that the horseshoe crab...
...has had to face major climatic changes
It has survived five catastrophic mass-extinction events
But current changes to the ocean are happening much faster than ever before
Human pressure is affecting the health of the modern ocean...
...on a much shorter scale
Therefore, the horseshoe crabs are not finding enough time...
...to adapt to these changes and thus, they are becoming more vulnerable
Along the coast, the team has unearthed something unexpected
The horseshoe crabs are moving into different areas...
...in search of new food sources and new habitats
We are quite happy, we found two horseshoe crabs...
...out here in this mangrove patch
They’re looking very healthy
This is a new habitat out there within the mangroves of the Sunderbans...
...where they have colonised
And we’ll continue to monitor these sites very well...
...and get an understanding why they’re colonising these new sites
The horseshoe crabs are survival specialists
But it’s too early to tell whether this recent migration and adaptation...
...is a masterstroke
This is a fight-back mechanism or I would say an adaptive mechanism
I believe this is a very, very bold step the horseshoe crabs are taking
They’re going into areas where food resources are a very different nature
We have to keep studying them to understand...
...whether it is a wise step for them or not
I’m sure it knows what it is doing
Question is: are we allowing that animal to let that change happen...
...so that it survives and prospers?
The horseshoe crabs aren’t the only marine species...
...which are trying to adjust to climate change
For the past two decades lobsters along the coast of North America...
...have been slowly moving north to colder, more favourable temperatures
And researchers have discovered...
...that some Arctic seabirds have moved their mating season...
...to earlier in the year when food is more available
The hope is, that if given enough time...
...many marine species will be able to adapt...
...to the growing changes in the ocean
If we can understand what kind of adaptive strategies they have undertaken...
...we can then see for many of the other endangered species...
...how would they cope with these changes...
...that is happening in the global ocean
Horseshoe crabs are showing signs...
...that they may adapt in the face of climate change
But to give them a fighting chance...
...Dr Bhadury is lobbying local government...
...to implement more marine-protected areas along this fragile coastline...
...to protect and conserve these animals and the ecosystem...
...from overfishing, pollution and construction
Eventually in the coast of India we will declare ecologically sensitive areas...
...where human-induced activity will completely stop
So, that horseshoe crabs will survive, thrive...
...and in the process many other marine organisms will survive and thrive
So, that is the approach that we are aiming to achieve in the long run
As the ocean changes, it is unclear which species will be able to cope
But by conserving and studying one of nature’s greatest survivors...
...scientists like Dr Bhadury, can gain a better sense...
...of how other marine species might migrate, adapt and evolve in the future
Hi I’m Claire and I directed this film
If you want to learn more about some of the innovative ways...
...people are trying to tackle the challenges facing the ocean...
...then click on the link opposite
If you want to watch more of The Protectors series, then click on the other link
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