The Open University since 2006
Alternatively you can skip the navigation by pressing 'Enter'.
Thinking Allowed 2016: 'Queer' wars, Nigerian beauty pageantsMonday, 30th May 2016 00:15 - BBC Radio 4Laurie Taylor and guests looks at the international polarisation over sexual rights and beauty contests in a... Read more: Thinking Allowed 2016: 'Queer' wars, Nigerian beauty pageants
The Educators: Series 2: Character LessonsMonday, 30th May 2016 23:30 - BBC Radio 4
Life - with David Attenborough: Creatures of the DeepTuesday, 31st May 2016 09:00 - Eden
Life - with David Attenborough: PlantsTuesday, 31st May 2016 10:00 - Eden
Old School With The Hairy Bikers: EPISODE 3Available until Sunday, 26th June 2016 20:00With only four weeks left at the Oxford Academy, we look to see how the old and young have learned from each other. Read more: Old School With The Hairy Bikers: EPISODE 3
Thinking Allowed 2016: 'Queer' wars, Nigerian beauty pageantsAvailable for over a year
All in the Mind - Summer 2016: Exams and the mental health of children, a community approach to suicide preventionAvailable for over a year
Thinking Allowed 2016: Glasgow gangs - Russian gangsAvailable for over a year
Life - with David AttenboroughDavid Attenborough explores the vibrant mix of life found on our plant - where it comes from, and... Read more: Life - with David Attenborough
Take the photographic memory testCan you capture scenes just by looking at them? Find out with our photographic memory test. Launch now: Take the photographic memory test
Una lengua en movimientoThis free course will develop your knowledge and understanding of the societies and cultures of... Try: Una lengua en movimiento now
Organisations and management accountingThis free course, Organisations and management accounting, examines the nature of organisations,... Try: Organisations and management accounting now
Managing eutrophication is a key element in maintaining the earths biodiversity. Eutrophication is a process mostly associated with human activity whereby ecosystems accumulate minerals. This free course explains how this process occurs, what its effects on different types of habitat are, and how it might be managed.
After studying this course, you should be able to:
- describe the principal differences between a eutrophic and an oligotrophic ecosystem
- explain the mechanisms by which species diversity is reduced as a result of eutrophication (Questions 2.1 and 2.2)
- contrast the anthropogenic sources that supply nitrogen and phosphorus to the wider environment, and describe how these sources can be controlled (Question 3.1)
- describe how living organisms can be used as monitors of the trophic status of ecosystems (Question 4.1)
- compare the advantages and disadvantages of three different methods for combating anthropogenic eutrophication (Question 4.2).
- Learning outcomes
- 1 Introduction
- 2 Effects of eutrophication
- 2.1 Effects on primary producers in freshwater ecosystems
- 2.2 Effects on consumers in freshwater ecosystems
- 2.3 Effects on terrestrial vegetation
- 2.4 Effects on marine systems
- 2.4.1 Estuarine species
- Current section: 2.4.2 Saltmarshes
- 3 Causes and mechanisms of eutrophication
- 4 Managing eutrophication
- 4.1 Measuring and monitoring eutrophication
- 4.2 Reducing eutrophication
- 4.3 Reducing the nutrient source
- 4.3 Reducing the nutrient source, continued
- 4.4 Reducing nutrient availability
- Keep on learning
Study this free course
Enrol to access the full course, get recognition for the skills you learn, track your progress and on completion gain a statement of participation to demonstrate your learning to others. Make your learning visible!
Marsh plant primary production is generally nitrogen limited, so saltmarsh vegetation responds readily to the artificial eutrophication that is now so common in nearshore waters. Eutrophication causes marked changes in plant communities in saltmarshes, just as it does in freshwater aquatic and terrestrial systems. Biomass production increases markedly as levels of eutrophication increase. Increases in the nitrogen content of plants cause dramatic changes in populations of marsh plant consumers: insect herbivores tend to increase (Figure 2.23) and so do numbers of carnivorous insects. Thus, increasing the nitrogen supply to saltmarshes has a dramatic bottom-up effect on marsh food webs. Eutrophication can also alter the outcome of competition among marsh plants, by changing the factor limiting growth. At low levels of nitrogen, plants that exploit below-ground resources most effectively, such as the saltmarsh rush (Juncus gerardii) are competitively dominant, but at higher nutrient levels dominance switches to plants that are good above-ground competitors, such as the common cord grass (Spartina anglica, Figure 2.24). In other words, as nitrogen availability increases, competition for light becomes relatively more important.
This free course includes adapted extracts from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Environmental Science courses or view the range of currently available OU Environmental Science courses.
Copyright & revisions
Originally published: Tuesday, 22nd March 2016
Last updated on: Tuesday, 22nd March 2016
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements and our FAQs section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.
- Latest OpenLearn pages
- Latest pages from OpenLearn - Environmental Science
- Latest pages tagged - biodiversity
- Latest pages tagged - phytoplankton
- Latest pages tagged - ecosystem
- Latest pages tagged - algae
- Latest pages tagged - nitrogen
- Latest pages tagged - phosphorus
- Latest pages tagged - S216_1
- Latest comments on this page
All our alternative formats are free for you to download, for more information about the different formats we offer please see our FAQs. The most frequently used are Word (for accessibility), PDF (for print) and ePub and Kindle to download to eReaders*.
- Word (5 MB)
- PDF (6.4 MB)
- ePub 3.0 (4 MB)
- ePub 2.0 (4 MB)
- Kindle (1.5 MB)
- RSS (426 KB)
- HTML (3.5 MB)
- SCORM (3.5 MB)
- OUXML Package (48 KB)
- OUXML File (168 KB)
- IMS Common cartridge
*Please note you will need an ePub and Mobi reader for these formats.