The oceans are vast, enormous and appear to go on for ever. Water covers 70% of the Earth’s surface and to call it the Blue Planet would seem apt. Whilst humans have lived by and traversed the oceans for centuries, our knowledge about life and chemistry in the oceans is still limited. The deep sea, down to 11,000m in the deep trenches, is of course even less explored but with new technology, our knowledge of the oceans is slowly increasing.
Oceans an essential source of life. The oceans contain 97% of all water and act as the ‘reversed lungs’ of the Earth’s water cycle through the evaporation of water into the atmosphere and its subsequent falling on land where it provides living creatures with drinking water. The oceans provide us with half the oxygen we breathe. They also act as a buffer on temperature fluctuations and regulate the climate. The oceans are all connected and water moves constantly, with surface water sinking at turning points and continuing to flow in the depths of the sea.
So will this seemingly unlimited source of sustainable ecologies be able to cope with the stresses from of an industrial world inhabited by 8 to 9 billion human beings? Well, it appears that it cannot. There are many ways human populations have an impact on the water, its chemistry and its organic life. We have done so for a long time, but are now becoming more aware that the ocean is not infinitely resilient to human encroachment. This paper is an attempt to highlight the interaction between humans and the ocean and the consequences of this interaction.
Long term changes in the oceans
The oceans absorb 30% of the CO2 from human activities. Over millennia the rate of absorption has changed, due to shifting continents and long term changes in the Earth’s climate, but it is now accelerating due to the burning of fossil fuels and the consequent increase in CO2 in the atmosphere. The oceans are becoming increasingly more acidic, dissolving calcium that creatures require. Many crabs and crustaceans depend upon it to build protective shields, and coral reefs require calcium for their construction. A lack of calcium could subtly but significantly damage the ability of life to thrive on the sea-bed.
However, that is not the only threat to the oceans and its living organisms.
In 2003 the UN specialised agency International Maritime Organisation (IMO) defined four major threats to the ocean and the marine life. They were, not necessarily in this order of importance: 1) aquatic invasive organisms in ballast water; 2) land-based sources of marine pollution; 3) over-exploitation of living marine resources and 4) physical alteration of coastal and marine habitat[i].
In the new Sustainable Development Goals discussed in the UN in 2015, the Goal 14 is ‘to Conserve and sustainably use the oceans, seas and marine resources for sustainable Development’. One of the facts is as much as 40 per cent of the world oceans are heavily affected by human activities, including pollution, depleted fisheries, and loss of coastal habitats. The first target (14.1) states: “by 2025, prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution”[ii].
Today, half the world’s population lives within 60 km of the sea, and three-quarters of all large cities are located on the coast[iii]. Humans have always lived along the Earth’s waters. They have used materials from timber trunks to reed floats to go exploring, to fish or to trade. The differential impact of today’s huge steel container ships, however, is potentially irrevocable. In the contemporary ‘Anthropocene’ period, the human-ecological relation between humans and nature is defined by the often unseen damage that industrial technologies cause beneath the surface of the oceans.
Since the beginning of the construction of steel ships in the mid-1800, ships have been designed with ballast water tanks which maintain the ship’s stability in varying loading conditions. The water for the ballast tanks is pumped in at ports where the ship has unloaded its cargo. This water may contain many various species of which some can survive the trip to the next port where the ship upload new cargo. The ballast water is then pumped out in the new environment. If the surviving species are able to stay alive in the new environment and even thrive in the new ecosystem; then the system can change considerably. This unforeseen transportation of life can subtly disturb the integrity of indigenous ecologies of ocean life.
The Asian phytoplankton algae Odontella (Biddulphia sinensis) was first recorded in the North Sea, having been brought there in ballast tanks[iv]. It was not until 1970 that scientific studies began to clarify the links between ballast water and surviving species, and that policy stakeholders started to engage with the need to prevent species being accidentally transported across the world. Regions such as the Black Sea and the waters surrounding the USA and Canada in particular faced a serious array of invasive species which when brought to the attention of the IMO led to international policy action. New technologies and new rules on how to discharge ballast water are now in place, and new conventions on ways of handling and treating ballast water from source to end were adopted in 2004. The ratification process (30 nations needed to get the convention into law) has now reached over 45 states and the convention is expected to be ratified in 2015 and thus become law. Nevertheless, implementation of the law has involved many hurdles. Old ships can be exempt, and new ships are fitted with technologies that remain at an experimental stage of their development. It remains a long process to ensure all ships are in line with the convention.
The case of ballast waters demonstrates that when international consensus is created around key issues, policies can be adopted. The challenges that face the oceans, however, are almost too broad and all-encompassing for targeted policies to address at once. Even when policies are laid down, ensuring their implementation requires major resource commitments at national and international levels.
Land-based sources of marine pollution
As long as populations along the coasts were tiny and waste was mostly from humans or organic waste, the dumping of waste matter into the sea could be dealt with by nature’s own way of breaking down organic materials by bacteria. But with the increasing of dense coastal populations in towns and cities, the waste ejected into the oceans is proving too much for ecosystems to cope with and it creates problems which require carefully planned solutions. As a brief historical note on coastal or riverine cities, the Harappa culture in the Indus valley which peaked in 2000 BC had an elaborated urban planning with a drainage system to cope with its creation of waste[v]. Today, the discarding of sewage waste is remains a major challenge for coastal cities.
In the UK, rudimentary sewage treatment plants were installed in cities from the mid-19th century. The Great Stink from the heavily polluted River Thames in London in 1858 forced the government to act, leading to the building of sewage systems by Bazalgette. This system took waste away from populated areas, but it was still dumped at sea without treatment. . Most UK cities and coastal towns had huge ocean outfalls until after 1945. Only in the 1980s did Liverpool’s 53 ocean outfalls begin to be connected and were fed into a treatment works.[vi] Later developments to this system included using sewage to fertilise farmlands, thus reducing the solids discharged to the oceans. Today, the UK’s use of anaerobic treatment means that waste water from urban areas now can be clean when it enters the sea.
However, these systems are not used uniformly across the world’s urban areas. Far too much of untreated sewage is still pumped into the oceans[vii]. Many countries in the world have no treatment at all. During the 1980s, Monte Carlo for instance continued to pipe its untreated sewage out into the Mediterranean, although in long-distance pipes so as not to directly pollute the beaches[viii]. Such systems fail to meet the EU’s criteria on waste water management.[ix]
A relatively new problem that affects the oceans is plastic waste. Although oil based plastics have been used for less than 70 years, in recent decades it has become an increasing problem for ocean life. Worldwide, plastics production is currently at staggeringly high levels, having increased from 1.7 million tonnes a year in the 1950s, to 299 million tonnes in 2013[x]. Anyone walking along a beach in Europe has inevitably seen rubbish blown up on the sand and that rubbish is now primarily plastic: containers, cups, bags, wrappers and bottles.
It is estimated that in 2010 more than 5 trillion pieces of plastic entered the sea, weighing over 250,000 tons, much floating on or near the surface but most disappearing under water[xi]. Plastics containing oil do not decompose in water but instead break apart into micro pieces. In the ocean gyres – massive vortexes rotating with the wind and currents – plastic parts and other debris form huge zones or conglomerates, sometimes several meters deep. There are five major gyres in the ocean, the largest in the North Pacific. It is estimated that only 5 – 10 % of the plastic we produce is recovered[xii] (although much is still in use), and even if much ends up in landfills, there it is degrading and washed into groundwater and eventually into the sea.
Not all plastic rubbish emanates from plastic bags or wrappers; some also comes from the unlikely source of facial cleanser, toothpaste or body scrubbers. Today some manufacturers use small microbeads[xiii], roughly 3,000 per tube[xiv] instead of residues of nut shells or other biodegradable resources, which are seen as too expensive. As these beads are tiny, less than 1 mm, they pass through the sewages system and into the ocean, where they are taken for food by phytoplankton and zooplanktons. Even if some are excreted, some stay in the intestines and as the creatures are in the bottom of the ocean food chain, they are eaten by predators that in turn ingest the particles. Eventually the particles will end up in fish that might be served on our dinner plates. This has not gone on for many years, but some estimates states that now over 470 million beads enter the ocean every day[xv].
This particular problem has now been highlighted and manufacturers are pledging not to – or have stopped – using microbeads. Many states are willing to impose new legislation against the use of microbeads. For instance Australia has done so and California is on its way with new legislation. The campaign to stop microbeads is creating an impact, and shows what can be achieved when civil society mobilises scientific research on human-ecological interactions.[xvi]
Plastic particles act as sponges for waterborne contaminants such as pesticides[xvii]. Invertebrates, fish and birds often eat the small particles. A report – “Sources, fates and effects of micro plastics in the marine environment – a global assessment” – was published in 2015 by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP), an advisory body that assists the United Nations on scientific aspects of marine environmental protection[xviii]. The report states that micro-plastic can now be found anywhere in the oceans:
“After entry into the ocean micro plastics can become globally distributed and have been found on beaches, in surface waters, seabed sediments and in a wide variety of biota (invertebrates, fish, birds, mammals), from the Arctic to Antarctic. They become concentrated in some locations such as ocean gyres, following long-distance transport, but also close to population centres, shipping routes and other major sources.”[xix]
The consequences of this inclusion of plastic particles, and their contamination, in oceanic food chains have not yet been fully explored. That something has to be done about it is becoming consensus in the scientific and even in the political environment. A report from UNEP in 2009 one suggestion was:
“National action plans or strategies should be based on development, implementation and enforcement of national legislation for waste management that includes marine litter, enhancement of national institutional mechanisms, strengthening of public, governmental and private sector partnerships, raising public awareness and education; and development of a framework for engaging key stakeholders and partners.”[xx]
In this context, it seems difficult to clear up our shores, let alone the oceans themselves. Countries around the globe have volunteers cleaning up litter on beaches through organisations such as Ocean Conservancy. The statistics on how much is removed are stunning. As an example, a clean-up along a 79 km stretch of South Africa coast in North, West and East Cape Provinces some 90,732 items were picked up by 7,532 volunteers, in all weighing over 10.25 tons[xxi].
The best solution would be to deal with the problem at its source: re-use, recycle, and reduce plastic consumption. Plastic must also be replaced with bio-degradable material whenever possible.
Countries in northern Europe are recycling nearly 100% of their plastic waste, mostly by incinerating the plastic, and generating electricity. Yet it is not only a top down solution that is needed – bottom up action on plastic is required to ensure recycling becomes a normal aspect of everyday life. Facilities for recycling are becoming increasingly available as legislation and the awareness of the litter problem increase, especially in Western Europe. However, even here, individuals have to be educated and supported to recycle; “Recycling is not an option – it is a responsibility” is a slogan stated on the sides of some recycling trucks in London. The willingness to change the way we use plastic should be strengthened through education that emphasises the harmful effects of its use.
Over-exploitation of living marine resources
According to the Marine Conservation Institute[xxii], the way we fish has contributed to the over-exploitation of marine life. What’s more, some fishing methods destroy or damage the very seafloor habitats where fish and many other species reside. Among all fishing techniques, bottom trawling – a fishing method that drags a large net across the sea floor – is the most destructive to our oceans, sometimes leaving up to 4 km long trails on the sea bed and severely damaging the seafloor ecosystems. The net indiscriminately catches every object it encounters. When the net is lifted on board the ship, much of the by-catches – fish, sea turtles, seabirds and marine mammals – are dumped overboard, usually dead or damaged. In cases of emergency, a ship might cut off its nets, but the nets released will continue to trap fish for years to come.
An example of the consequences of over-fishing is the loss of cod on the Grand Banks on the eastern shores of the Canada where overfishing caused the ecological system collapse.
When the Italian John Cabot first explored the Grand banks he said it was so full of fish that you could just scope them up with a bucket. In the 1600s English fishermen said the sea was so full of cod that it was hard to row a boat through them. The location of the Grand Banks at the northern edge of the warm Gulf Stream where it meets the cold Labrador in shallow water on the Banks, creates an ideal place for all kinds of fish, shellfish and other marine species. The cod industry flourished there, feeding not just Canada, but Europe and more distant countries.
Contemporary industrial scale fishing has relied on high catches involving bigger ships with larger trawling nets, and in 1968 some 800,000 tons of fish, mostly cod, was taken out of the sea[xxiii]. However, by 1974, this catch had fallen to 300,000 tons. Fishing continued but it was not until late 1980s when, in spite of local fishermen’s warnings, scientists begun to realise that the cod population was in serious trouble. Fishing zones have since been introduced, but this increased fishing instead of keeping it under control[xxiv]. In 1992 the Canadian Government finally acted and imposed a total ban on cod fishing on the Grand Banks which caused a collapse of the Newfoundland fishing industry.
The cod have not returned. The ecosystem on the Grand Banks has changed. Shrimps and crabs are now the major catch source for the fishing industry. As stated in The British Sea Fishing website[xxv]:
“The intensive bottom trawling that had taken place in the Grand Banks was seen as a major factor. It was thought that the constant trawls had torn up the seabed to such an extent that marine life could no longer be supported in the area. The shellfish and seaweed beds which had supported crustaceans, molluscs and small fish had been destroyed and without them there was nothing for the cod to feed on.”
The Grand Banks example is unfortunately not the only one example of over-fishing. Today species such as Bluefin tuna, sharks and rays are nearly extinct in the Mediterranean and certain varieties of salmon and sturgeon in the Atlantic, just as examples[xxvi]. There are other threats to sea living creatures. Dynamiting the coral reef to stun the fish is also practiced, although illegal. The explosives used are not only killing fish, but also destroy flora and fauna and it takes very long time to heal the coral reefs[xxvii]. International waters are hard to control and illegal fishing continues widely[xxviii].
Physical alteration of coastal and marine habitat
As so many people now live along the world’s coast, the coastline is constantly being altered through human endeavours. These ports are now focal points in an interconnected global economy, defined by flurries of human activity; mining, construction, tourism. As such, coasts are a clear manifestation of human relations with nature in the Anthropocene. Natural ecosystems including mangroves, marshes and coral reefs along the coast are vulnerable to these human undertakings. Yet these ecosystems also act as a critical line of defence for the coastline and many fulfil roles as breeding grounds for creatures.
In tropical and sub-tropical coasts, mangroves form an important forest protecting coastlines against storms, currents, waves and tidal surges. They are also a haven for fish and birds seeking food and shelter.[xxix] In many areas they are under serious threat. Oil spills, logging, clearance for oil pipes, urban development and shrimp farming; all pose a threat to the aquatic mangroves and the complex ecosystems that depend on them. Mangroves also play an important role in facilitating agriculture, as they allow water to drain off the land.
Whilst clearly under threat, it is important to note that mangroves can be replanted and work is being done to highlight the need to do so. CHEC led workshops in 2012 and 2013 that trained civil society from West Africa on mangrove protection, but lacks the resources to replicate this initiative across the Commonwealth. Other bodies are also taking important steps to protect mangrove reserves. National parks can protect mangrove forests, by applying indigenous knowledge and adopting Ramsar conventions.[xxx] Ramsar is an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.[xxxi]
Beaches are important sites for many species that symbiotically maintain the health of the beach ecosystem for other life forms. Lugworm is one of these, living in tidal flats, where they ingest and aerate the sediment, helping maintain it for a large variety of other marine organisms. Mussels also play an important role in marine ecosystems by filtering water, which removes bacteria and toxins. They are also a source of food for a variety of birds. However, a lugworm cannot see the difference between micro-plastic and food, but when it eats too much plastic, it suffers from stress and cannot do its job properly, and this is also true for mussels.[xxxii]
Exploitation of the oceans for non-organic resources (oil, minerals)
Deep sea drilling for oil and gas has been a central technique for oil extraction since the late 1800s. In the mid-1900s drilling began in water deeper than 30 meter and by the millennium deep sea drilling at depths up to 500 m had become possible, such as in the Golden Triangle between Brazil, the Gulf of Mexico and western Africa. This type of drilling is now used in India, the South China Sea and in the Caspian Sea.[xxxiii]
Oil spills are a nearly unavoidable outcome of this oil exploration. Several very serious spills have occurred through drilling, such as the Deepwater Horizon in 2010, but also during the transport of oil, such as Exxon Valdez in 1979 and Amoco Cadiz in 1978. The oceans provide a certain degree of cleaning up after oil, as there are microbes that feed off it, especially in warmer waters[xxxiv]. That is not enough sufficient to clean up an entire spill, however, which – as many of us are familiar with from TV images broadcast after accidents such as the Deepwater Horizon – can kill birds, fish and many other species. Human intervention to stop the spread of the oil slicks is, of course, absolutely necessary. With exploration companies looking at the Arctic Ocean for new well sites, the potential risks from an oil leak in this much harsher environment should not be taken lightly.
The seabed of oceans contains many minerals, formed from crystallisation of elements in the water and from flows in the volcanic activity along the continental plate boundaries. Gold and diamonds are harvested on the continental shelf outside southern Africa, and trials have been done at greater depth for modules of manganese, iron and cobalt, sometime to a depth up to 4,000 m. Back in the early 1980s there was great commercial interest in manganese nodules and cobalt crusts. This initial euphoria over marine mining led to the International Seabed Authority (ISA) being established in Jamaica, and the United Nations Convention on the Law of the Sea (UNCLOS) being signed in 1982 – the “constitution for the seas”. Since entering into force in 1994, this major convention has formed the basis for signatories’ legal rights to use the marine resources on the sea floor outside national territorial waters.
New interest has emerged in the possibility of mining rare minerals in the very deepest hydrothermal vents on the sea floor where the fluids are rich in diamonds, gold, iron sand, and rare earth elements.[xxxv] In 2014 a Canadian company, Nautilus Minerals, signed an agreement with Papua New Guinea to extract minerals from Solwara 1 in the Bismarck Sea to harvest 1.6 million tonnes copper and gold. Nearly 20 other licences are in place for similar deep sea mining. The environmental impacts of such extractive industries are very uncertain as the organisms living at these depths are not very well known, but complex ecosystems persist, even at the depth of 4,000 m. How to restore the ecosystems at this depth after mining stops is being investigated through cooperation between the industry, the International Seabed Authority and scientists, such as Dr Cindy Lee Van Dover, Duke University Marine Laboratory,[xxxvi] an expert on deep sea trenches, and organisations against mining such as Deep Sea Mining Campaign.[xxxvii]
Another emerging problem is noise. Many of the Cetaceans, such as whales and dolphins communicate by sound or ‘songs’ that can be heard for miles under water. But there is now noise interference from ships’ propellers, sonars on military submarines, drilling and extraction of gas, oil and minerals.[xxxviii] These noises can distract whales from their course and possibly cause the beaching of the animals. Noise can also be used to scare animals, such as harbour porpoises, away from fishing nets, although the effect of the ‘ringers’ and ‘pingers’ used by fishing boats are not well known.
The establishment of offshore wind farms has highlighted the noise problem, but there is a willingness to adjust the timing of the building of the bases for the wind turbines, something which can create much disturbing noise, to accommodate fish breeding and migration. Some major shipping routes should be – and already have been – moved away from important marine mammal habitats.
The threats to the oceans are many, as seen above. However, there is an increasing understanding of the particular challenges they pose and policies are being developed to tackle them.
In fishing, especially, marine protection areas are set up to protect habitat and breeding grounds. Consultations are taken worldwide; including engagement with local fisherfolk, with control given to local areas can improve the viability of the protection zones. The European Union (EU) Fisheries Policy is formulated in cooperation between fisheries, politicians and scientists and is regularly updated; latest changes were approved in January 2014.[xxxix] Similar rules are and should be adopted globally. This is where the Commonwealth as an international broker can play a major role in global sustainability.
When it comes to pollution of the sea many steps have already been taken to control and to limit the impact waste has on the ocean. EU’s Urban Waste Water Directive, implemented in 1991, is dealing with planning, regulating, monitoring and information about urban waste in Europe and this will contribute to less waste dirty water being sent to the oceans.[xl] Again, these policies are in place in many parts of the world, and there is much to be learnt from the implementations of such rules.
Plastic in the ocean is also coming higher up on the agenda for policy makers and international organisations. Manufacturers of plastic are increasing involved in trying to lessen the effects of their output by cooperation in education for recycling. The cosmetic industry is increasingly abstaining from using microbeads from their products.
Much of these changes are due to an increasing activism from local and international organisations, working locally or collaborating with people affected by the problems.
The ocean is not infinite – there is a limit to what it can cope with. As we human beings are very dependent on the ocean for our life we should take care of it. It is not just for food and water, but for the pleasure of being able to enjoy a clean beach, swim in clear water and let the distance horizon of the sea inspire our curiosity of what is far away and beyond what we can see. Many threats have been mentioned here and it is a bleak picture, but there is also hope in the way our awareness of our impact on the oceans has increased. Calls for actions to tackle the consequences must be taken now. Action cannot be taken only at one level – the political or on ground level – but we should all act together.
Pictures by Eva Ekehorn, unless otherwise stated
p1:Thames estuary, Jellyfish, picture from the Aquarium in Genoa, Italy; p2:Ballast water tanks, IMO (with permission); p3: Beach cleaners in South Africa, from Marin Debris; p4: Grand Union Canal, London, 5: Photo in the ‘The Rooms’, http://www.therooms.ca/ , St John’s, Newfoundland, Canada; p6:Mangrove; p7: Ryde tidal flats, Isle of Wight, UK, Semisubmersible oil platform ‘Balmoral’, for the North Sea, GVA International, p8: Tilbury Dock, London, UK,
p9: Nash Point, River Severn, Wales, UK
[i] (IMO website)
[vi] Note by Prof Ian Douglas
[vii] For Europe see: http://www.eea.europa.eu/data-and-maps/uwwtd/interactive-maps
[viii] Personal interview with the Monte Carlo municipality services
[xi] Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea; Marcus Eriksen, * E-mail: email@example.com
Affiliation: Five Gyres Institute, Los Angeles, California, United States of America; Laurent C. M. Lebreton, et al. Published: December 10, 2014. DOI: 10.1371/journal.pone.0111913 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111913
[xiii] The microbeads used in personal care products are mainly made of polyethylene (PE), but can be also be made of polypropylene (PP), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and nylon. http://www.beatthemicrobead.org/en/science
[xviii] http://www.imarest.org/themarineprofessional/item/1458-mirco-plastics-are-a-macro-problem; www.gesamp.org/ http://www.gesamp.org/data/gesamp/files/media/Publications/Reports_and_studies_90/gallery_2230/object_2461_large.pdf
[xix] GESAMP: Sources, fate and effects of microplastics in the marine environment: a global assessment . Report editor: Peter Kershaw
[xxi] 2013 International Coastal Cleanup, South Africa. John Kieser, Sustainability Manager, Plastic SA