Alarm bells are ringing in oceans around the globe. Recent studies show a sharper decline in marine biodiversity than earlier forecasts. A good part of precious sea and ocean life may be on the verge of extinction. What is worse, these studies indicate that the potential extinction of species, from tiny corals to large fish, could be comparable to the five great mass extinctions in antiquity during which much of life perished from this planet.
These warnings merit serious attention since they come from some of the most respected names in marine science associated with the International Programme on the State of the Ocean (IPSO) at Oxford and the International Union for Conservation of Nature (IUCN). The implications of biological impoverishment on this scale are indeed ominous and far-reaching. Apart from sharks, whales and commercially important fish, almost all sea life is facing the extreme threat of extinction. This would also have a devastating impact on the livelihood of millions of fisher folk dwelling in coastal areas.
While fisheries resources are critical for global food and nutritional security, other aquatic fauna and flora, including algae, seaweeds, corals and innumerable others, are important sources of raw material, genes and molecules that can be of immense utility for combating existing and future challenges confronting humankind. The adverse impact of this catastrophe is already there to see. The harvests of many common species of commercial fish have already begun to shrink due to either erosion in their population or their migration to inaccessible zones. As a result, numerous marine species are getting concentrated in small zones, increasing their vulnerability to depletion. Things would only get worse rather than better, since few countries are paying much attention to this catastrophe.
Understandably, and shamefully, human activity is the source of the problem. Apart from human-induced depletion of the earth’s protective ozone layer and the consequential changes in climate, other factors like intense overexploitation of ocean resources, including fisheries, habitat destruction and growing sedimentation and pollution of the seas, are impairing marine eco-systems and hastening biodiversity loss. Moreover, the unabated flow of toxic industrial effluents and chemical residues, coupled with the run-off of fertiliser nutrients from agricultural fields, is causing acidification of sea water. This, in turn, is creating dead zones in oceans due to anoxia (near-total absence of oxygen) or hypoxia (inadequate oxygen), making it difficult for living creatures to survive. It is worth noting that about 60 per cent of the global population lives within a 100 km of the coastline and a sizeable part of the rest around rivers and other water courses which ultimately empty into the seas. Untreated discharges from these habitations, besides water-based human activities for livelihood, trade, tourism and recreation, are polluting the oceans and degrading their capacity to support life.
It is around such human habitations that well-conceived interventions are needed to curb biodiversity erosion. The most critical need is to prevent the flow of pollutants into the sea directly or through river waters. Ongoing national initiatives in this direction are obviously not enough. Joint global action, marked by binding national targets of the kind being envisaged to combat climate change, may perhaps yield better results. Oceans, like the environment, constitute a common global resource that needs to be conserved to protect the marine ecology and avert biodiversity disaster.