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| Barley harvest. By U.S. Department of Agriculture [Public domain], via Wikimedia Commons. |
Agriculture has long been regarded as a stepping stone in
human history; elevating hunter-gather societies from a violent and precarious
existence propelling humans into a post-cave dwelling reality promising
improved health and longevity coupled with decreased workloads. After deeper
examination by biological anthropologists, however, this rosy perception has
been put into question. One of the more conspicuous effects was reduced dental
health resulting from an exponential reliance on a carbohydrate based diet
along with a decline in nutritional quality as diet became less varied;
affecting growth and development[2]. Negative effects of agriculture
are not felt by humans alone.
As technology advanced agriculture inevitably became more
and more sophisticated. In the present day, influences of a wide range impact
the way humans cultivate land; from a continually increasing population to a
calcified capitalist attitude in society. Such pressures translate into a
yearning for greater yield in crop at the lowest possible cost. Consequently,
technologies such as fertilisers are now widely used.
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| Fertilising operations. Graham Horn [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons. |
Employing fertilisers in agriculture introduces such chemicals as ammonium and
nitrate to soil and water[4]. The nitrogen that is added to the soil
may exceed levels that can be absorbed by plants[1] and this can be
a significant issue regarding marine pollution, as we will now explore.
Surplus nitrogen in soil and water from the excessive use of
fertilisers migrates into watercourses through agricultural run-off; when
considering marine pollution this is specifically an issue in coastal farmland
as the excess nitrogen is transported into the marine environment.
Eutrophication is a type of pollution that is characterised by an explosive
growth of algae, also known as algal blooms, as a result of increased
concentrations of growth-promoting nutrients[3]. When the algae die
and are eaten by bacteria the oxygen levels of the water can become hypoxic
(low oxygen) or anoxic (completely depleted of oxygen), having potential
catastrophic effects on animals inhabiting the aquatic environment; hypoxia
induces stress and anoxic conditions can be fatal[3].
Marine eutrophication occurs in much the same way and is as
an ecosystem response to the increased availability of nutrients, such as
nitrogen, that are essential for plant growth[1]. Marine waters
enriched with nitrogen can promote an explosion in algae and planktonic growth
leading to hypoxic or anoxic conditions posing threats to the surrounding
marine life. Marine eutrophication has been observed in the Baltic Sea;
significantly increased nutrient concentrations measured in the 1990s compared
to the 1950s (before large scale nutrient input began) resulted in increased occurrence
of fast-growing algae forming algal mats that decomposed in the lower levels
inducing anoxic conditions[5].
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| Phytoplankton bloom off western Iceland. By NASA Goddard Space Flight Center (Flickr: Phytoplankton bloom off western Iceland) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons |
Ever improving technology arouses questions surrounding a
seemingly old-fashioned way to cultivate the land (machines have merely
replaced man whilst methods remain relatively unchanged): is it necessary? Is a
change needed in societal attitude? Is there less harmful alternatives?
The future of humanity is uncertain; food security is
becoming an increasing worry with threatening conditions that could affect our
ability to maintain the status quo of food production. As we re-think global
food production, issues surrounding the use of technologies such as fertilisers
should not be overlooked. Marine eutrophication, seemingly specific, has far
reaching implications as the oceans are such a vital aspect of our past,
present and future. An all-encompassing view of our food production wouldn’t go
a miss!
- Ben
References:
[1] Cosme, N. and
Niero, M., 2017. Modelling the influence of changing climate in present and
future marine eutrophication impacts from spring barley production. Journal of
Cleaner Production 140, 537-546
[2] Larsen, C.
S., 1995. Biological Changes in Human Populations with Agriculture. Annual
Review of Anthropology 24, 185-213
[3] National
Oceanic and Atmospheric Administration, 2017. Nutrient Pollution –
Eutrophication. Available at: https://oceanservice.noaa.gov/education/kits/estuaries/media/supp_estuar09b_eutro.html
(Accessed: 8 December 2017)
[4] Socolow, R
H., 1999. Nitrogen management and the future of food: Lessons from the
management of energy and carbon. Proceedings of the National Academy of
Sciences of the United States of America 96, doi: 10.1073/pnas.96.11.6001
[5] UK Marine
Special Areas of Conservation, undated. Eutrophication. Available at: http://www.ukmarinesac.org.uk/communities/infralittoral/ik5_3.htm#a1
(Accessed: 8 December 2017)
