16 Marine Resource (2): Distribution, Livelihood & Scarcity Concerns

Dr Soma Sarkar

     LEARNING Objectives:

After studying this lesson you should be able to:

• Explain basic problems of marine ecosystem.
• Understand the impact of various anthropogenic activities on marine environment,
• Explore major emerging marine issues related to climate change, and
• Identify the major internationally agreements to protect marine ecosystem.

KEYWORDS

Marine ecosystem, fisheries, eutrophication, climate change

Introduction

Since 2009, we watch 08 June as “World Oceans Day”, as a chance to raise worldwide consciousness of the recent challenges confronted by the global groups regarding the oceans. The oceans form the basic components to food security, wellbeing and survival of all life, control our atmosphere and are essential to biosphere. Humankind has lived with the ocean and survived by its services since time immemorial. But with ever rising global population pressure, the sustainable future of the oceans and the coasts are in question. Vulnerable marine biological communities, for example, corals, and fisheries are being harmed by over-exploitation; unlawful, unreported, illegal and unregulated fishing invasive alien species; destructive fishing practices; and marine contamination, particularly from land-based sources. Extraction of mineral resources from marine ecosystem is loaded with risks and could conceivably cause extreme decay of the marine condition.

An expected 33% of the world’s coastal locales are at high threat of degradation with the maximum risk possibly in Europe. tresses to the coastal and marine assets in Latin America and the Caribbean increased remarkably with tourism, infrastructural advancement and the release of silt, waste and industry contaminants. Erosion of sea coasts are a recent burning issue in various African nations, where local communities are unfavorably influenced by changing sedimentation concentration in most downstream part or increased erosion in degraded catchments because of dam construction in upstreams. Eutrophication in the Baltic, North, and Black seas is also an issue, and an extreme one is in areas circumscribing the Mediterranean and Caspian seas. The over-exploitation of marine fisheries and the monetary effect of such practices, cause far reaching impact in parts of Asia and the Pacific, Europe, North America, and West Asia. Climate change another stressor to marine biological system, may likewise influence ocean mixing and flow patterns with remarkable consequences on the efficiency of marine biological communities/ecosystems, and the area of fisheries. Whatever maybe the future of marine and coastal resource extraction; one must remember that protected, healthy and profitable oceans and seas are necessary to human prosperity, financial security and development with sustainability. (Figure 1).

Figure1: Map of 18 regional seas and 64 large marine ecosystems, 2011

1. Impact of mineral oil on marine environment

According to World Ocean Review 2014, “in 2011, the world’s natural gas reserves and resources totalled around 772 trillion cubic metres….Resources account for the major share, amounting to 577 trillion cubic metres, with unconventional natural gas resources (coal seam gas (CSG)/coalbed methane/shale gas) comprising around 60 per cent of the total natural gas resource base…. For many years, offshore natural gas and oil production was restricted to shallow waters, however, as many older deposits have become exhausted, companies have increasingly moved into deeper waters. In 2007, oil was extracted from 157 fields at depths of more than 500 metres; while in 2000 there were only 44 such fields…..The downside here is that extraction is complex and expensive, as for instance, extraction from fields at great depths requires floating production, and drilling vessels, or pumping stations permanently mounted on the ocean bed.” On doing so, a heavy troll is often exerted over the environment by the global oil industry. Onshore, if there is soil pollution crisis by oil from leaking pipelines; offshore, marine life, coats and feathers of seabirds, and coastlines gets polluted by oil spilled from damaged tankers. Therefore, major impacts of mineral oil contamination on marine ecosystem have been as follows:

   I. Impact on marine fauna life: Filter feeders, for example, mussels and other marine living beings often gulp down oil alongside their food. The dangerous hydrocarbons in the oil stop their internal filtration systems, and exterminate them rapidly. Regardless of the possibility that they survive, the poisons can be passed along the food chain when these poisoned mussels are consumed. Moreover, their metabolic procedures and development are impeded. “In other organisms, reproduction is adversely affected, even genetic damage can happen. Furthermore, many marine fauna lose their sense of direction, because many of them use very fine concentrations of certain substances in the sea water as a means of finding their way around their environment, and making it more difficult for them to forage or identify partners for reproduction. Marine mammals, such as otters, can die of cold if their fur is coated with oil. Furthermore, mammals often ingest oil when they attempt to clean their oil-coated fur, and this can poison them” (WOR, 2014). Fish assimilate lethal hydrocarbons through their skin and gills.

II. Impact on marine plants, mangroves and slalt marshes: In marine plants, oil pollution disturbs the gas-exchange through the leaves, and food exchange by the roots that kill the plant. In mangrove biological system, the vegetation dies when covered in oil, annihilating the natural habitat of numerous flora and fauna species. Moreover, oil infiltrates to greater depth in the soft soil of mangrove ecosystem and stays in the ground for long stretches. Essentially salt swamps, where the vegetation shapes the habitat for exceptionally well-adjusted widely varied vegetation and animal life, are lost when oil devastates ecosystem. “Mangroves, salt marshes and soft substrates take at least two years to sometimes more than 20 years to recover from oil pollution” (WOR,2014).

III. Impact on sea birds: The most obvious effect of mineral oil is the damage caused to seabirds’ plumage. Oil smudged plumage cannot carry out its essential functions of repelling water and to provide thermal insulation. In the process, the bird loses body heat and dies.

2. Over-fertilization of the seas

The high productivity in sea water is a consequence of nutrients that are transported by waterways from the land into the ocean. Phosphate and nitrogen compounds makes most of the nutrient enrichment, which plants need for growth, and in addition devoured by phytoplanktons; and consequently frame the base of the sustenance web in the marine biological community. The high productivity of coastal waters in the long run makes them progressively alluring place for aquaculture. However, in many thickly populated areas of the Earth, excessive amounts of nutrients (i.e., a huge extent originate from the intensive horticultural use of fertilizers) are finding their way into the marine waters. Nitrogen and phosphate compounds from untreated  waste water and through the air from the burning of petroleum products are likewise transported to the ocean. All these leads to algal bloom, but a serious threat are caused due to propagation of toxic algae, which if enter the human or marine mammals’ food chain via fishes and clams it can cause death.

“The blooms of non-toxic algae can also create problems when they die. The dead algae sink to the bottom. There they are broken down by microorganisms through a process that depletes oxygen in the water. Low oxygen concentrations in the seawater can lead to large-scale mortality of fish and crustaceans. When the oxygen concentration continues to drop, most of the other species living in the sea floor also disappear. Only a few species that can tolerate low oxygen levels remain, and if the bottom water finally becomes completely devoid of oxygen, even these organisms will die off” (WOR, 2014). The effects of eutrophication have come to light since the 1960s. Scientists have noted that more the plentiful algal blooms, more will be zone of oxygen-defficiency in coastal regions, and finally major changes in coastal ecosystems. A true dilemma therefore exists: with global population growth, the requirement for agricultural production of grain will also increase, but this result in huge quantity of fertilizers mixing with oceans via the rivers.

3. Impact of sand and gravel extraction

Sand and gravel are extracted by ships from the ocean floor using suction dredging. According to WOR, 2014, “the extent of the damage and destruction that is imposed upon marine habitats by the large-scale sand and gravel extraction has long been a subject of heated discussion. The North Sea fishing industry, for example, has voiced the fears that fishing could be impacted negatively by such operations”. The impact can

I. Driving away of fishes by the noise of the suction dredgers;

II. “The hunting and spawning grounds of the fish are destroyed by the dredging sediment that was stirred up”;

III.  “Fishing equipment such as lobster pots, are ruined by the suction dredgers”.

IV. Extraction changes the composition of the seabed sediments. “When gravel or coarse-grained sand is removed, the sites afterwards often fill with finer sand which is washed away by the current. Fine-grained areas attract different sea dwellers than coarse-grained areas, and can change the species diversity of the site.”

V. “Fish stocks are being compromised by the suspended sediment being stirred up, and that catches will dwindle as a result.”

    4. Impact of sea-floor mining

Scientists agree that mining manganese nodules in the future would be a severe interruption into the deep-sea ecosystem, because the harvesting machines would plough-up big areas of the marine floor. In WOR2014, following detrimental impacts are assumed:

I.  “While ploughing through the sea floor the harvesting machines stir up sediment, and ocean currents can move this sediment cloud through the area. When the sediments settle down to the sea floor again, sensitive organisms, particularly immobile ones are covered and die. Many of the organisms live buried within the deep-sea sediments especially in the upper 15 centimetres of the sea floor.”

II.  “Directly in the operation area most organisms are killed, as they either cannot escape the plough quickly enough, including snails, sea cucumbers and worms, or they can be vacuumed up with the nodules and die during the cleaning process on the ship.”

III.  “The mining, pumping and cleaning of the manganese nodules creates noise and vibrations that disturb marine mammals such as dolphins, and force them to flee from their natural area.”

IV.  “The sediment-laden water produced by the cleaning of manganese nodules is released into the sea from the ships, the sediment cloud so created even at near-surface waters could disturb the growth of algae and other planktonic organisms.”

5.  Marine fisheries at stake

I. “For decades, the catch from the world’s fisheries steadily increased – with the result that many fish stocks are now classified as overexploited or depleted. Failed fisheries policies and poor fisheries management are to blame for this situation. Short-term profits appear to take priority over the development of a low- impact, sustainable fisheries sector that will remain economically viable in the long term”…. World Oceanic Review 1, 2014. The statement gives a synoptic view of the current marine fisheries situation. “Due to the great demand for fishery products, fish farming is also steadily expanding, especially in Asian countries, as food industry sectors. Many fish species raised in the fish farms are predatory fish, which rely on a supply of wild-caught fish as feed. Therefore, switching to consumption of farmed fish alone does not necessarily protect wild fish stocks”.

 II. Regarding overexploitation the review reports that, “overexploitation particularly affects long-lived fish species such as redfish, which take several years to reach maturity and begin spawning. In extreme cases, it may even lead to the extinction of the stock. For example, stocks of cod fish in the Northwest Atlantic off the United States coast have collapsed after years of overfishing. Biologists now believe that due to the immense disruption of the marine ecosystem, it has crossed a tipping point and that even with a total ban on fishing, cod stocks will not recover”. According to FAO estimates, “there has been a steady increase in the proportion of overexploited (being exploited above a level that is believed to be sustainable in the long term) and depleted (catches are well below historical levels, irrespective of the amount of fishing effort exerted) stocks since the 1970s. Furthermore, due to a lack of alternatives, commercial fishing is increasingly turning to such species that were previously regarded as unprofitable, or of poor quality, or unfit for consumption.”

III. The WOR report further raise concern regarding the impact of litters on marine life, where it reports that, “The National Academy of Sciences in the USA estimated in 1997 that around 6.4 million tonnes of litter enter the world’s oceans each year. Researchers discovered that the floating debris accumulates in the middle of the oceans – in the North Pacific, known as Great Pacific Garbage Patch. Much of the litter is harmless, but some of it is responsible for marine mammal deaths. Seals and otters, for example, which feed on fish, crabs and sea urchins on the sea floor, are frequent casualties. The ghost nets poses a threat to fish, turtles, dolphins and other creatures that can become trapped in the nets and die. Propelled by currents, these nets can tear up corals and damage other habitats such as sponge reefs.”

6.  Impacts of climate change on the marine environment

I. Coral bleaching: A notable amongst the most dreadful impacts of climate change is coral bleaching. It is a hazard to corals caused by high water temperatures that kills them. As of late, marine environments have seen ceaseless and serious coral bleaching scenes around the globe, with coral mortality rising upto 70% in a few locales.

II. Extreme weather: Most researchers believe that climate variability will proclaim a new period of extraordinary, unpredictable and unusual weather. The frequency and intensity of cyclones and heavier precipitation may rise. Such incidents would result to the physical harm to coral reefs, other coastal biological systems and communities. For example, hurricane Hugo and Marilyn hit the US Virgin Islands National Park in 1989 and 1995, respectively, and did huge destruction to coral ecosystems.

  III. Species encroaching on alien territories: “As the ocean warms, the location of the ideal water temperature may shift for many species. A study has shown that fish in the North Sea have moved further towards north or into deeper water in response to rising sea temperatures. Similarly, the distribution of penguin species in the Antarctic Peninsula region, is changing with reductions in sea ice due to global warming” (CBD, 2009).

IV. Altered lifestyles of marine species: “Rising temperatures can directly affect the metabolism, life cycle and behaviour of the marine species. For many species, temperature serves as a cue for reproduction, and any changes in sea temperature could affect their successful breeding, including the timing of reproduction and migration, physiology, morphology, behaviour, population density and distributions of many different species. For example, the number of male and female offspring is determined by temperature for marine turtles, some fish and copepod. Changing climate could, therefore, skew sex ratios and threaten population survival”.(CBD, 2009)

V. Rising sea levels: Reports suggests that the worldwide ocean levels may ascend by as much as 69cm during the next 100 years, mainly due to the glaciers and polar ice melting, and thermal expansion of warmer water. This will seriously affect marine biological systems, i.e., the amount of light available to aquatic plants, and algae reliant on photosynthesis could be diminished, whereas coastal habitats are already being flooded. Mangrove ecosystem may have to face some greatest challenges due to rapid sea level rise, as it requires stable sea levels for long term survival.

VI. Acidic oceans: In the processes of engrossing a huge amount of the carbon dioxide discharged by anthropogenic factors, the oceans are becoming acidic in character. Fish and other gilled marine animal may find it harder to breathe in acidic water, as it is extremely difficult to extract dissolved oxygen from it. In addition, continuous acidification of seawater, joined by restraint of the calcification procedure (which is the development of calcium carbonate by marine life forms, species like shellfish, crabs, lobsters and corals) may find it hard to build their calcium carbonate shells. In a few zones, these shells may even begin to break down.

7.  International agreements and outlook

To protect the marine ecosystem, a number of international conventions have been established that demonstrates significant levels of international cooperation.

Regarding international agreements, “the 1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (the London

Convention); and, the 1973 International Convention for the Prevention of Pollution from Ships (MARPOL) address marine pollution”.

The United Nations Convention on the Law of the Sea (UNCLOS 1982), “ratified by 160 countries, and since 1994, represents a integrated approach towards shared use of the oceans and their resources, addressing navigation, economic rights, marine conservation, pollution, and scientific exploration”.

The 2004 International Convention for the Control and Management of Ships’ “Ballast Water and Sediments, exemplifies collaborative actions to address the introduction of alien invasive species, as it can cause significant environmental and economic damage”.

Another notable global attempt towards marine ecosystem is the “Global Programme of Action for the Protection of the Marine Environment from Landbased Activities (GPA), adopted by 108 governments, and the EC in 1995. Although not enforceable, the GPA was designed to guide both national and regional authorities, in undertaking sustained action to prevent, reduce and eliminate marine degradation from land-based activities. Many countries acknowledged subscribing to its goals, providing a means for developing collaborative strategies to address coastal and offshore water degradation from influent freshwaters.”

SUMMARY

Marine ecosystem, which is a major source of food, a climate change regulator, a means of transport for international shipping so on, have great potential towards resources generation, but that could potentially cause severe degradation.

415 coastal areas are eutrophic out of which 169 have hypoxic dead zones. Global nutrient run-off increased by approximately 15% since 1970. Pollution and litters continues to be a significant threat to marine biodiversity. The use of destructive fishing practices further amplifies the impacts of unsustainable fishing on marine biodiversity and habitats.

Overexploitation of marine species to meet consumer demand threatens biodiversity, with unregulated overconsumption contributing to declines marine biodiversity. By-catch from fisheries can be a major threat to groups, such as sharks, turtles and albatrosses.

REFERENCES

1. Bax, N., Williamson, A., Aguero, M., Gonzalez, E. and Geeves, W. (2003). Marine invasive alien species: a threat to global biodiversity. Marine Policy 27, 313–323.
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3. CBD (2009). Scientific Synthesis of the Impacts of Ocean Fertilization on Marine Biodiversity. CBD Technical Series 45. Secretariat of the Convention on Biological Diversity, Montreal.
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