Salinization

Introduction

Salinization will be evaluated by referring to the causes, humans as contributors, and the effect of vulnerability and consequences in order to get a better idea of what the phenomenon of salinization entails.

Salinization causes


Source: Azernews

Salinity is a significant environmental contaminant. As Cañedo-Argüelles et al. (2013) note, both “primary (accumulation of salts originating from natural sources) and secondary salinization (which refer to anthropogenic increases in salinity and which is further amplified by climate change)” are responsible for this phenomena.

 

Extensive land-use changes in dryland regions occur, causing run-off salinities to increase as salt is mobilized from subsurface waters. Secondary salinization is caused by irrigation. Natural lakes’ salinities in drylands accelerate as water is diverted from inflows for irrigation. Deforestation leads to salinization. Mining activity is responsible for salts that enter rivers. Rising saline groundwater tables cause the salinization of some fresh waters. In the cold regions of the world stream salinization is the result of the use of salts as de-icing agents for roads (Williams et al., 2000; Löfgren, 2001; Ruth, 2003; Cañedo-Argüelles et al. 2013). Clearing of natural vegetation is another source.
 

Coal and salt mining, soda production factories, sewage and industrial effluents, and increases in river salinities may result from the construction of impoundments are also sources of salinization. (Williams 2001; Cañedo-Argüelles et al. 2013). Salinity intrusion can be caused by sea level rise (SLR) and extreme events such as cyclones. Natural salinity of rivers is complex including, “weathering of the catchment; sea spray; small amounts of salts dissolved in rainwater as a consequence of evaporation of seawater (Cañedo-Argüelles et al. 2013).
 

Salinization causes leading to other impacts

Dryland salinity causes soil erosion. The removal of indigenous plants and the clearing of forests lead to soil erosion, and amplify the occurrence of more salts present in the soil. Salinity can be ascribed to prolonged wetness and where there is limited surface cover. This will lead to soils to erode. Cyclone and storm surges induced by climate change force saline water into agricultural lands along the coast, which damages crops not only in the year the cyclone hits, but for several years afterwards (Rabbani et al. 2013). The risk of flooding occurs when shallow water tables occur as soils don’t have the capacity to adequately absorb rainfall, which ultimately leads to higher run-off rates. Terrestrial biodiversity is also negatively impacted as it’s destroyed at an unprecedented rate, causing loss of biodiversity in salt-affected areas. Food shortages will be prevalent and would then ultimately lead to famine.

Spatial and temporal scale

Spatial
Salinity and its severity is greatly felt in dryland countries, and semi-arid and arid regions. Salinization occur in arid and cold regions. In the arid and semi-arid regions of the world where crop production consumes large quantities of water, irrigation and rising of groundwater tables are the main causes of secondary salinization In the cold regions of the world stream salinization is the result of the use of salts as de-icing agents for roads. It is significant in parts of central and South America, south-western North America, the Middle East and central Asia, and parts of Australia. Coastal communities are experiencing saline intrusion caused by extreme events. The salinization of freshwater lakes is most obvious and significant in dryland regions but is not confined to them (Cañedo-Argüelles et al. 2013; Williams 2001).

Temporal

Salts can be stored in soils, sub-soils and groundwater because of aridity previously experienced and then released after a long period and occurs at different time scales. Irrigation leads to mobilising large fossil salt storage, dating from another saline geographical history in the soil. Cyclone and storm surges induced by climate change force saline water into agricultural lands along the coast, which damages crops not only in the year the cyclone hits, but for several years afterwards.

Future changes will lead to further salinization. Climate change is likely to increase river salinity in some regions e.g. a decrease in the amount of precipitation. The Australian Dryland Salinity Assessment (NLWRA, 2000)(as cited in Cañedo-Argüelles et al. 2013), predicted that 3.1 million ha of land will be affected by salt by the year 2050 and up to 20,000km of streams could be significantly salt affected over the next 20 years.
 

Humans as contributors

Salinization can be natural or human-induced. Many inland waters are becoming more saline from human activities. Change is being brought about by secondary or anthropogenic salinization. In this process, catchment changes and other anthropogenic disturbances to hydrological cycles increase salt loads to water-bodies: fresh waters become saline and saline waters become even more saline (Rabbani et al. 2013; Williams 2001).

Anthropogenic salinization is distinct from natural or primary salinization which is responsible for the development of natural salt lakes. Primary salinization involves the accumulation in closed basins of salts from rainwater and leached from terrestrial sources at rates unaffected by human activities. Natural salt lakes have been the focus of most limnologic studies of saline waters (Williams 2001).

Increasing energy demands are likely to increase mining activity, e.g. coal consumption for electricity is expected to increase 42% from 2008 to 2030 (US Department of Energy, 2008). Therefore, the future predictions clearly indicate that river salinization will globally increase (i.e. more streams will be impacted and the salt stress will increase in already degraded streams) (Cañedo-Argüelles et al. 2013).
 

Poverty, low-level resilience, and lack of alternative livelihoods, together with climate-induced hazards, are responsible for huge losses. The proportion of salinity-free farmland has gone down over the past 20 years, from more than 60% to nil. Almost all saline-free and low-salinity farmland has turned into medium- or high-salinity farmland, which has a severe impact on agricultural productivity. Salinity intrusion is the main cause of declining rice production (Rabbani et al. 2013).

Climate change, including salinity intrusion caused by extreme events (e.g., cyclone and storm surge) and slow-onset events (e.g., SLR) are leading to negative impacts on almost every economic sector, including agriculture, livelihood activities, food security and public health. A future cyclone with a higher level of storm surge could cause saline intrusion further into the landmass, thus threatening the whole coastal region and its 33 million people. Poorer households will experience significantly greater loss and damage as a result (Rabbani et al. 2013).
 

The extreme poor are disproportionately affected by salinity as a percentage of their income, by comparison to non-poor households. About one-third of people living on the coast will be badly affected. This is mainly because most of the coastal population depends on rice cultivation for their livelihoods and food security. Poor farmers are severely affected by salinity intrusion in rice fields (Rabbani et al. 2013).
 

Households are bearing the burden of loss and damage in rice farming, and the costs of repair and reconstruction of damaged infrastructure and local facilities. Loss of productivity due to illness caused by food shortages would push these poorer groups into even greater poverty. Increasingly, people are moving from the coast, mainly because of loss of livelihood opportunities. This internal migration (rural-urban, coastal-central) will intensify as sea levels continue to rise, as extreme weather events become more frequent, and if adaptation options remain inadequate (Rabbani et al. 2013).
 

By 1980, between 80 and 110 million ha of irrigated land (34–47% of all irrigated land) had been effected by salinization to some degree (FAO 1990). The impacts of anthropogenic salinization are far-reaching, increasing, deleterious, and largely irreparable. Environmental, social, and economic costs are high. In some countries, anthropogenic salinization represents the most important threat to water resources (Williams 2001). Economic losses include the loss or a diminished value of water supplies for domestic, agricultural, and other needs.
 

Conclusion

The relative importance of salt lakes is now rapidly and significantly increasing. Management responses are of several sorts. Cessation of vegetation clearance, restriction of dryland agriculture, and tree-planting will mitigate further salinization. Integrated catchment management is the key practice and needs to be emphasized more than the management of salinized waters (Williams 2001).

References:

Cañedo Argüelles, M., B.J. Kefford, C. Piscart, N. Prat, R.B. Schäfer and C.-J. Schulz (2013).

'Salinization of rivers: an urgent ecological issue'. Environmental Pollution, Volume 173, pp157–167.
 

Rabbani, G., Rahman, A., and Mainuddin, K. 2013. Salinity-induced loss and damage to farming households in coastal Bangladesh. International Journal of Global Warming, Volume 5, pp 400.
 

Middleton, N. 2008. A Global Casino: An introduction to Environmental Issues. 4th Edition. London: Hodder Education.
 

Williams, W.D. 2001. Anthropogenic salinization of inland waters. Hydrobiologia, Volume 466, pp 329-337.

An ocean full of plastic

Introduction

Marine animals, already being susceptible to the dangers of other man-made processes, must be also confronted by the threat of plastic debris. The accumulation of anthropogenic debris (in particular plastic pollution) have resulted in huge threats on marine biota. The plastic threat is a growing global phenomenon. People have seen the ocean as an inexhaustible food source as well as a dumping ground without thinking about the consequences thereof. However, the ocean isn’t limitless and sustainability of our seas isn’t taking place. Marine litter is degraded at a very slow rate, and coupled with the exponential pace and quantity of debris that is disposed, ultimately leads to an unfortunate increase in plastic pollution. Thus, greater awareness on this significant problem is required.

Defining marine plastic debris

Marine debris is defined as any persistent manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment. It includes items made or lost by people, and those deliberately discarded into or unintentionally lost in the marine environment (Gall & Thompson 2015). Glass, metal, paper, and plastic are some of the most commonly found marine debris materials.


Source: Ocean Leadership Organisation

Ocean plastic statistics

Source: Ocean Conservancy

Plastic debris is of specific concern due to its abundance and persistent occurrence in oceans. One reason for a rapid decline in biological diversity is because of unsustainable human activities and as a result of this have accelerated extinction rates.

Land-based sources are responsible for around 80 per cent of all marine pollution. Global production of plastics has increased considerably over the last few decades from 5 million tonnes per year in the 1960s to 280 million tonnes per year in 2011. There are estimated to be over 5 trillion plastic pieces weighing over 250,000 tonnes afloat at sea ((UN, 2004 & Eriksen et al., 2014 as cited in WWF Living Blue Planet Report 2015; Gall & Thompson 2015).

It is estimated that about 6.4 million tons of marine litter are disposed in the oceans and seas each year. According to other estimates and calculations, some 8 million items of marine litter are dumped in oceans and seas every day, approximately 5 million of which (solid waste) are thrown overboard or lost from ships. Furthermore, it has been estimated that over 13,000 pieces of plastic litter are floating on every square kilometre of ocean today (UNEP. 2005. Marine Litter: An analytical overview).

There are approximately 35,500 tonnes of microplastics (tiny plastic particles) floating in our ocean (Eriksen et al., 2014 as cited in WWF Living Blue Planet Report 2015). Even with improved waste disposal management and recycling initiatives, a large amount of plastics will be swept into watercourses, which will eventually end up in the oceans. Over 60% of the world population live within 100km. Furthermore, because of rapidly growing global population, land-based activities it will ultimately lead to marine pollution taking exponentially place. 

Reasons why this phenomenon occurs and its various contributors
Reasons why plastic is utilised
Plastic materials are commercially successful as they are durable and economically affordable. Moreover, because they are low cost, plastic is readily available and utilised as a disposable material source. The very qualities of durability that make plastic convenient to use, however, also make it a persistent, non-degradable, permanent presence in the marine environment. When discarded, lost, or abandoned in the world's seas, plastic debris adversely affects living creatures there. (Joyner & Scot Frew 1991).

Types, sources, and locations of ocean plastic debris

Plastic pollution poses a serious threat as it is concentrated in areas where marine life is abundantly found. Marine debris can travel vast distances. Plastic fragments on beaches are derived either from inland sources and are transported to coasts by rivers, wind, man-made drainage systems or human activity, or directly from the oceans where low density floating varieties accumulate and are transported across great distance. Marine litter can blow around; remain floating on the water surface; drift in the water column; get entangled on shallow, tidal bottoms; or sink to the seabed at various depths. It is found in oceans and seas, in salt marshes and estuaries, in mangroves, on coral reefs, and on all kinds of shores. Beachgoers also contribute tremendously when they accidentally lose, carelessly handle, or leave behind plastic materials. There are major inputs of plastic litter from land-based sources in densely populated or industrialized areas, most in the form of packaging. Types and amounts of plastic debris on beaches are controlled mainly by topography, current and storm activity, proximity to litter sources and extent of beach use. Deposition and retention of plastics on beaches however, are largely controlled by the composition and degradation rates of the plastic particles (Corcoran et al. 2009; Derraik 2002; UNEP Marine Litter: An analytical overview 2005).




Source: Denver Post

Impacts on people and marine species
Unfortunately, plastic debris into the ocean has become an increasingly growing problem and the density thereof has also taken place at an astronomically fast rate.

Human-related impacts

Undoubtedly knowledge about plastic’s harmful impacts on marine biota has increased and relates to environmental, economic, safety, health, and cultural impacts. It also detrimentally impacts human health, while simultaneously damages people’s livelihoods, as well as spoil the beaches aesthetically and for people’s enjoyment, it creates navigation hazards, and negatively affects tourism, too. Therefore it has negative socio-economic consequences.

Impacts on marine species

Conversely, the marine environment has been perniciously affected by the plastic revolution which have resulted in a serious environmental issue. Marine populations have fallen significantly as numerous important habitats have been destroyed. Importantly, plastic pollution significantly threatens ecosystems and is harmful to organisms, it increases the transport of organic and inorganic contaminants, it smothers coral reefs, disturb habitats from mechanical beach cleaning, and breakdown by chemical weathering and mechanical erosion is minimal at sea. Marine litter is also a source of accumulation of toxic substances in the marine environment, and environmental changes due to the transfer and introduction of invasive species (UNEP Marine Litter: An analytical overview 2005). The biological and ecological performance of certain individuals will unfortunately be compromised.

Species of crustaceans, fish, turtles, marine birds, and mammals are affected and the scope and severity of it varies according to the species and plastic type. Species listed on the IUCN Red List are particularly vulnerable as they are at a greater risk of becoming extinct. At least 17 per cent of species affected by entanglement and ingestion of marine debris are listed as threatened or near threatened on the IUCN Red List (Gall and Thompson, 2014; WWF Living Blue Planet Report 2015).

 

Non-degradable plastic

The greatest threat is the durable properties of plastic as plastic materials persist in the marine environment long after disposal and may take up to 400 years to degrade. What is worrisome is the fact that more and more plastic are disposed of every day, and accumulate in the oceans at an even faster rate. These non-biodegradable items attract encrusting organisms as drift plastics. The drifting debris acts as a kind of oasis, attracting other marine animals in search of prey (Joyner & Frew 1991). Unfortunately, the durable properties of plastic lead to killing repeatedly. Another potential danger is the accumulation of plastic debris on the sea floor as certain seabirds select specific plastic shapes and colours, mistaking them for prey.

Source: Envirocon.org

The impact of marine debris on marine life is of particular concern, resulting into ingestion of plastic debris and entanglement in packaging bands, drift nets and synthetic ropes and lines. More than half of all known species of marine mammal and sea bird have ingested or become entangled in marine debris. The severity of the impact of it vary according to the type of debris and vary between species, and even between individuals as some are able to withstand it better than others. Furthermore, fatalities of birds, turtles, fish, and marine mammals are well-documented.

(Warning, some of the pictures below are disturbing).

Entanglement

Entanglement in plastic debris, especially with regards to discarded fishing gear, poses a serious threat to marine animals. When an animal is entangled, it may drown, or impair its ability to catch food or to avoid predators, reduce its fitness as it leads to an increase in energetic costs of travel, or incur wounds from abrasive or cutting action of the debris. Sea birds with stomachs full of plastic waste and turtles entangled in plastic bags are a serious marine problem. Lost or abandoned fishing nets pose a particular great risk.

Source: Wikipedia

Sea birds

Recreational fishermen also contribute to the problem as they don’t properly discard plastic line and birds dive beneath the water for their prey but become ensnared in the nearly invisible plastic monofilament line. It also reduce food consumption, limiting their ability to lay down fat deposits and thus reduces fitness.

Source: Earth Rangers

Ingestion
Ingested plastic particles regularly remain inside species, leading to harmful effects. Many organisms ingest small plastic particles, working their way up to the food chain. Among seabirds, plastic ingestion is directly correlated to foraging strategies and technique, and diet. The durable properties of plastic prevent species from easily digesting it. Small fish and seabirds who ingest plastic debris lead to a reduction in food uptake, cause internal injury, and, sadly, death following blockage of intestinal tract. While feeding on schools of fish, whales can unintentionally ingest plastic debris. Other species mistake translucent plastic bags for squid. Afflicted animals may be eaten or sink to the sea bottom.





Source: Shutterhead



Source: Wikipedia


Turtles
All known species of sea turtle have ingested or become entangled in marine debris. Sea turtle hatchlings, which spend their juvenile stage along ocean fronts, can unintentionally consume plastic pellets. In later life, sea turtles sometimes frequent ocean fronts in search of food. These turtles are known to ingest plastic bags, which are mistaken for jellyfish which can be fatal (Joyner & Frew 1991). Young sea turtles are significantly vulnerable and their survival is at risk.



Source: Energy Digital

Source: Project Aware



Solutions to the problem
Plastic pollution has severely affected the marine environment. Usage of plastics continues to increase, while simultaneously accelerating the amount of plastics polluting the marine environment. The fact is that marine debris does not belong in the marine environment. The threat of plastics to the marine environment has been ignored for a very long time and its severity and serious have only been recognised recently. However, solutions have so far only been a drop in the ocean and more effective solutions are required. Gall & Thompson (2015) suggest that “finding effective solutions requires a holistic approach, considering the entire life cycle of items that become marine debris including green chemistry and design and manufacturing as well as effective waste management and prevention and removal of marine debris”. Nevertheless, attempts have been made to conserve the world’s oceans by way of international legislation. The biggest challenge here is to enforce it effectively in such a vast area as the world’s oceans.

Education is another valuably powerful tool and can be particularly effective in schools. Through this way children can change their own habits while concurrently positively impacting their local community, too, starting with their family and friends. Thus, they can be a catalyst for important change which would lead to a community be willing to act sustainably in order to make also an eco-friendly contribution and foster an enhancement of ecological consciousness. Derraik (2002) notes that “thinking globally and acting locally is a fundamental attitude to reduce such an environmental threat”. He further notes that “the general public and the scientific community have the responsibility of ensuring that governments and businesses change their attitudes towards the problem”.

These two aspects can successfully and effectively be the best way forward to solve such a dire environmental problem.

Conclusion

Beaches across the globe are strewed with plastic debris and pose an imminent and global threat to marine species. Marine habitats, including shorelines, estuaries, and the sea surfaces, are negatively impacted by manmade debris. An ecosystem degraded by pollution and fragmented by development will recover slower from the effects of overfishing and less resilient to the impacts of climate change (WWF Living Blue Planet Report 2015). It is axiomatic that plastic debris pollution, being an environmental hazard that threatens our oceans’ biodiversity, must be urgently addressed.

References:

Derraik, J.G.B. 2002. The Pollution Of The Marine Environment By Plastic Debris: A Review. Marine Pollution Bulletin 44 842–852.

Corcoran, P.L., Biesinger, M.C., & Grifi, M. 2009. Plastics And Beaches: A Degrading Relationship. Marine Pollution Bulletin 58 80–84.

Gall, S.C., & Thompson, R.C. 2015. The Impact Of Debris On Marine Life. Marine Pollution Bulletin 92 170–179.

Joyner, C.C. & Scot Frew, S. 1991. Plastic Pollution In The Marine Environment. Ocean Development & International Law 22:1, 33-69.

WWF. 2015. Living Blue Planet Report: Species, Habitats And Human Well-Being.

UNEP. 2005. Marine Litter: An Analytical Overview.