Implications Of Global Warming And Marine Litter?
A New Dead Zone In The Bay Of Bengal
Ocean-our Present and Future
The ocean covers 71% of earth’s surface and contains 97% of planet’s water. This ocean is the life support system for the planet earth. The oceans have been playing a key role in the world in spreading civilizations, cultures, religions and affect the climate and weather. Humankind has been using the oceans since time immemorial for venturing for explorations, navigation, wars, trade, leisure and for obtaining living and non-living resources. Oceans have been the main protein supplier for the humankind. With the gradual increase of population and depleting of land-based resources, many countries are now focusing even more attention on the oceans. The oceans have been the lifeline of many countries and the economic livewire as well. Oceans carry 90% of internationally traded goods. Oceans generate half of the oxygen we breath and absorbs 40% of Carbon Dioxide we produce. Ocean also absorbs heat generated by humans and from the sun.
Urbanization, pollution, over-exploitation and climate change can be detrimental to the sustenance of a balanced coastal ecosystem. There is a growing awareness in the world today that we need to be careful about exploiting the ocean-based economy, as we cannot afford to damage the very ocean that is our lifeline. The world oceans are under an unprecedented level of pressure from commercial exploitations. The bad news is that already as much as 40% of world oceans are heavily impacted by human activities, including pollution, depleted fisheries and loss of coastal habitats.
A Dead Zone in the Bay of Bengal
A new massive “Dead Zone” has been detected by a team of scientists from the National Institute of Oceanography (India), University of Southern Denmark and Max Planck Institute for Marine Microbiology in Germany in the latter part of 2016. Until then, there had been three major dead zones in the world; two in eastern tropical Pacific and one in the Arabian Sea, west of India.
A Dead Zone is typically a large area of water from 50 to 100 meters below the surface, to depths of many hundreds of meters. The Bay of Bengal Dead Zone is approximately the size of 60,000 square kilometers. Marine ‘Dead Zones’ contains no oxygen. Oxygen depletion can take place due to natural causes and human activities. Lack of oxygen make the ecosystem to shift to anaerobic metabolism. This pushes microorganism living within the Oxygen Minimum Zone (OMZ) to get energy by degrading organic matter in a process that removes vast amounts of nitrogen, a key nutrient for life in the oceans. This upsets the nitrogen balance of the whole planet.
The Bay of Bengal (BOB) Dead Zone presents scientist with an enigma as it contains traces of oxygen. The BOB receives enormous amount of run-offs from numerous major and minor rivers such as the Brahmaputra and the Ganges that bring large amounts of pollutants such as fertilizer, particles and organic matter from agriculture, aquaculture, industries and untreated sewer and plastics. This could lead to massive plankton blooms further reducing oxygen content. The traces of oxygen present in the BOB dead zone facilitates the microbial process and depleting water of nitrogen. When oxygen goes away the marine life start using nitrate, which results in depleting nitrogen too. However, there are no large fish or marine life in this dead zone, although above the layer of the dead zone there can be fish and other marine species and plants. This productive layer also produces waste materials and that also contribute to the propagation of the dead zone.
The ‘Dead Zones’ can impact marine ecosystem; fisheries and the ecological and biological diversity. The alarming news is that the Dead Zones are increasing in size around the world. Global warming, pollution and ocean acidification are cited as probable causes for creating ‘Dead Zones’. Scientist have concluded that global warming is real and the ocean temperature has risen by 13 % more than anticipated. The arctic ice is melting and the northern sea route is opening up for commercial shipping. This may be good news for shipping but extremely bad news for world oceans. Dead Zones will affect the life on the ocean and depleting of nitrogen will cause nitrogen imbalances and could lead to serious human consequences. Oceans are approaching a tipping point. If the fisheries are depleted, millions of people will lose livelihood and this could lead to mass migrations and conflict.
We need a sea change in government attitudes and policies. We need to understand that the ocean is not a bottomless pit that we can dispose plastics and other material at will. It is estimated that 80 % ocean pollution is land-based. We need to understand what is good for the oceans and to the life in the oceans. Lack of understanding and disrespect cannot be tolerated anymore. Ocean should be considered as a wilderness that needs conservation. We need informed management and corrections to flawed policies in consultation with the communities that depend on it. We need carefully crafted solutions based on scientific studies and modelling. Protecting our oceans is not a luxury. It is a necessity, if not it could impact on our way of life, economy and environment.
We have no choice but to work together and change the course of destruction. We must prevent economic over-exploitation and unsustainable forms of waste management. It can not be an individual country effort but we need to act as a region. We need regional solutions as this issue will impact the whole region and not only the individual culprits. We can also take guidance from United Nations Resolution 70/1, “transforming our world: the 2030 agenda for sustainable development, goal number 14 – “Life Below Water: to conserve and sustainably use oceans, seas and marine resources for sustainable development.”
We need to exploit and use the oceans in a sustainable manner. We need a harmonious relationship with our ocean as it is fundamental to life on earth. We need to act now.