Until a few years back, one often got amazed at the sight of tropical waters located by the side of equator because the area was soaked in super-richness of species, as one would find its wide variety herein and this used to be something typical to this region. For instance, sea-turtles, a hefty reserve of tuna fish, sharks, vibrant coral reefs and so forth.
Going by the assumptions made by eminent ecologists, such was the regular sight for centuries but now, as the ocean has absorbed a lot of heat, it has made it harder for certain species to survive therein, which is also an alarm to global warming to be unrolled.
Not mincing words, such a new trend where species hunt for cooler watery dwelling nearing poles, marine ecosystem is bound to have a tremendous bearing and human earning is going to be affected too. It is said that similar event took place around 252 millions years ago which resulted in the annihilation of 90% of sea animals.
Such globally occurring arrangement, where concentration of species is thin at the poles while it soars at the middle of the world or at equator, takes the shape of a bell, indicating species abundance. Researchers scanned records of around 50 thousand sea animals to know about their habitat and regions they are largely found and distributed, beginning from 1955 and were flabbergasted on finding a constant descent in such a bell curve.
Therefore, in the backdrop of warming oceans, poles have been explored as the preferred shores with modest temperatures and species easily make their way there. Now in case of equator region, if this gets warmer by 0.6 degree Celsius in a span of 50 years, such is termed humble rise, in comparison to rise in temperature in high altitudes and species have to slip further looking for their thermal niche.
Now, because of climate change, past decades have witnessed warming of oceans too and at equator, number of species also went down.
Ecologists and researchers, going by modelling approach, made the expectation of such a re-structuring to happen 5 years back but now, they are well-equipped with observations.
Now, for the purpose of getting to know about the richness of certain species like pelagic fish, reef fish and molluscs, their number dwindled and wasn’t otherwise, at the latitudes where temperature of annual sea-surface hovers around 20 degree Celsius.
In today’s times, in the northern hemisphere and in latitudes falling around 30 degrees North, which exactly is southern China and Mexico while around 20 degrees in the south, that is North Australia and South Brazil, species thickness is said to be higher.
Such Phenomenon Is Not Alien:
Not surprisingly, biodiversity on this planet has had a sheer response to global warming and such an event is not new to be unrolled.
252 Millions Years Ago…..:
It is said that by the end of Permian geological period which happened nearly 252 million years ago, global temperatures soared by 10 degree Celsius and remain constant for abut 30 thousand to 60 thousand years, which again can be attributed to greenhouse gas emissions occurring from volcano eruptions taken place in Siberia.
A study is carried out about fossils of that time revealing the fat fact about biodiversity richness concentrated at the equator which got flattened and vegetation dispersed to surrounding areas. During such wider spread of global biodiversity, 90% of marine species got perished.
A study also makes this certainty uncover that around 1,25,000 years ago, widespread warming was there, during which, reef corals moved away from tropics which is also documented in fossil records, even though, luckily, no mention of any annihilation is in sight.
Study researchers point out that hat their finding may serve as a warning about the global warming that we experience today and which also warn about gross annihilation of species in coming decades as species migrate to subtropics, where they may have to struggle in adaptation as well as for existence.
As We Stand Today:
Around 15,000 years ago, when the last ice-age ended, the period saw the glory of forams at the equator, which is plankton kind, with single cell and hard shell, but its strength records a sharp fall ever since. Such is considered to be a worrying trend as plankton is among the major species concerning foodweb.
Going by the study, the decline appears rapid in past decades, which is largely due to climate change inflicted by humans.
When the tropical ecosystems species vanish in quick time and in a large number, it also hampers the resilience of ecology to combat changes taking place in our environment, emboldening the fact that ecosystem persistence is being compromised.
However, concentration of species is found enlarged at such tropical regions, which highlights that there will be species violators and novel type of hostile associations for survival. Citing an example, when tropical fish swims to Sydney Harbour, they would need to compete with temperate species for food and habitat.
Alarmingly, this could lead to a collapse in ecosystem, as the study reveals of the time when Permian period ended and Triassic period began and species got annihilated causing a great change to services which centred ecosystem, such as food supplies etc.
Truly, such a change will have affects on popular livelihoods. For instance, some nations on tropical islands, manage huge revenue from tuna fishing and specific licenses are issued to fishermen allowing their sails into the territorial waters. But as tuna fishes are quick enough to move, they are attracted to subtropics and beyond the sovereign waters which island nations control.
In same way, subtropical regions also attract reef species, manta rays, whale and sharks and sea turtles which tourists flock to catch a glimpse of and find amazement in.
What Steps To Follow?
A guideline was drafted in the Paris Climate Accords which is about reducing the emissions. Besides, there are other opportunities too, by way of which, biodiversity can be safeguarded and hopefully, region around the equator can still retain its share from nature.
As of now, it is claimed that 2.7% of the ocean is under conservation effort and reserves are either fully protected, which is still, short of what was promised, i.e. 10%, target, under the UN Convention on Biological Diversity of 2020.
Interestingly, a new group of nations, 41 in number, has come onto the forefront, which call for 30% of oceanic protection by the time, we step into the year 2030.
But, considering the 30 by 30 target, it would call for a number of remedial steps to be initiated, such as:
A complete restriction on seafloor mining,
To discourage fishing in reserves that destroys habitats and is a big source of carbon dioxide in atmosphere too, just like what aviation industry contributes globally.
But certainly, such measures will ensure a free and flourishing biodiversity and would promote resilience in ecology too.
Making reserves in accordance with climate positives would a shield to biodiversity from harsh changes of the future which climate may witness. As a great step, we could keep marine life reserves in refugia where climate stability lasts for many years.
Now, we are equipped with sound and irrefutable evidence that climate change is cause of great disturbance in ecological pattern that was considered to be so robust and to undermine this destructive sea-change, our efforts should not get delayed. This is a wake-up call.