Oceans Are Important to Us: Why and How?
M Kabir Ahmed ,
Regulate the Earth system:
In the North Atlantic Ocean, wind-driven surface currents head poleward from the equator, cooling all the while and eventually sinking at high latitudes into the ocean basins (thermohaline circulation). Extensive mixing takes place across ocean basins, reducing differences between them and making the Earth’s ocean a global system. On their journey, the water masses transport heat, gas, and matter around the globe. This circulation has a large impact on the climate of our planet.
Ocean currents transport large amounts of heat and water around the world and constantly interact with the atmosphere, which enables the ocean to act as a heat sink to delay the full effects of climate change. Carbon is continuously cycled between reservoirs in the ocean, on land and in the atmosphere, where it occurs primarily as CO2. In the ocean, CO2 dissolves in seawater forming carbonic acid and is ultimately removed from the marine system through processes such as the formation of calcium carbonate and the creation of limestone.
Carbon exists in many forms in the ocean, mainly as dissolved CO2 and organic matter in the form of small creatures, such as plankton. The largest reservoir is the deep ocean, which contains close to 40,000 Gt C. The exchange of carbon between the deep ocean and the fast-responding system above takes several hundred years.
Microalgae are responsible for greater than 50% of global primary production. In doing so, they play a major role in the global carbon cycle by consuming CO2 from the atmosphere and positively influencing climate change.
Supply living and non-living Resources:
The oceans are a major source of food. Worldwide approximately half of the population live in coastal zones and about a billion people rely on fish as their main source of protein. Blue (marine) biotechnology is an emerging sector with the huge potential to use marine biological systems and living organisms or derivatives to produce innovative products and services for the health and beauty and medical industries. Apart from harvesting food from the sea, many industrial processes worldwide rely on the marine environment for resources, such as oil, gas and marine aggregates. The oceans offer enormous potential for renewable energy technologies, such as offshore wind farms, tidal or wave energy devices.
Provide social and economic goods and services:
Coastal and marine tourism is a large global industry supporting regional economies as coastal and marine environments become more accessible. Eco-tourism, in particular, is a fast-growing sector. International seaborne trade relies on regular and safe routes for freight and passengers. World seaborne trade is estimated at approximately 28,000bn tonne miles. 90% of EU external trade and 40% of EU internal trade is carried by sea and in the UK the shipping sector employs over 30,000 people. Approximately half of the world’s population live and work within 100km of the sea and 100 million people live less than 1 meter above present sea level. Marine habitats such as coral reefs and salt marshes provide natural coastal defenses and nursery grounds for fisheries as well as diverse ecosystems.
Escalating natural disturbance events, including sea level rise and storms, will increase damage to coastal infrastructure, housing, transport (including ports and major coastal cities), as well as have a significant impact on vulnerable habitats, such as corals and salt marshes, which provide natural coastal protection and important marine environments. There will be serious risks and increasing pressures on coastal protection in South East Asia, small islands in the Caribbean and the Pacific, and large coastal cities, such as Tokyo, New York, Cairo, and London. Rising sea levels will result in tens of millions more people flooded each year with 3-4 degree centigrade warming. Changing sea level, ocean currents, extreme weather events and other changes to climatic processes, will impact on aquaculture, shipping, food production, tourism and recreational industries. Increased rainfall, melting of sea ice, glaciers and the Greenland ice sheet are all possible consequences of higher temperatures and could reduce North Atlantic surface water salinity sufficiently to slow down, or even stop, the thermohaline circulation which gives the UK its mild climate. Once stopped, the consequences would be a cooling of northwest Europe.
Changes to biological and chemical processes:
Ocean biogeochemistry (i.e. the cycling of elements like carbon and nitrogen) is driven by activity in the ocean surface where sufficient light exists to stimulate photosynthesis. This process converts CO2 and other nutrients into living biomass, on which all subsequent ocean productivity depends. Research has shown that the most significant changes in seawater temperature and pH levels so far have been observed in the surface layers of the oceans where the base of the marine food web is most active. Phytoplankton, microscopic oceanic plants which live in the surface waters, take in CO2 during growth and convert it into complex organic compounds. During biological cycles, some of the carbon is broken down and transported to the depths by fecal matter and dead organisms, creating a net transfer of carbon from the surface to the deep ocean in a process known as the ‘biological pump’. The combination of increased levels of CO2 and reduced productivity of phytoplankton will reduce the oceans’ ability to process the
There will be major poleward shifts in species’ distributions. Over the past 30 years, a 10-degree latitude northward shift in the distribution of many plankton and fish species has already been observed. There will be changes to the seasonal timing of plankton production with consequences for plankton predator species, such as fish, whose own life cycles are timed according to the seasonal production of particular prey species. Many organisms, such as corals, urchins, and species at the base of the food chain, will be impaired in their ability to digest, reproduce and grow due to the effects of ocean acidification. Declining productivity at the base of the food chain will cause changes or loss of food resources for marine species. This will impact on the availability and accessibility of many commercially exploited fish (e.g. decline in stocks of cold water species such as cod). A 2-degree Centigrade warming could cause loss of 15-40% of biodiversity. The decline in populations of native species may be caused by an increased invasion of
Let us take proper measures for research and management of the Physical, Chemical and Biological Resources of the Bay of Bengal. We are educating Marine Sciences and Fisheries in different Universities and Institutions of the country. But we have no single active institutions working on the Physical, Chemical and Biological Resources of the Bay of Bengal. Unfortunate and very unfortunate. We are very busy with less important work and have no attention on important aspects. We have known that there is a National Oceanographic Institute somewhere in Bangladesh. As most senior Marine Biologist we are unknown about that institute and its activities. Are the workers of that Institute from Oceanographic educational background?