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Class presentations
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02/05/11 => Researching for the team

Describe and evaluate the methods for measuring changes in abiotic and biotic components of an ecosystem due to a specific human activity.


SHIREEN

INTENDED OIL SPILLS FOR WAR


Oil spills in ocean waters by humans can occur for a multitude of reasons, but the most harmful are the intended spills rather than accidental ones. Intended oil spills for reasons like terrorism, war or theft tend to be more environmentally damaging because they are planned to be difficult to repair or to respond effectively, occurring in secluded places or intended sabotaging of efforts.

METHODS OF MEASURING CHANGES IN ABIOTIC COMPONENTS OF MARINE ECOSYSTEM

The main assessment is how much oil has been released into ocean waters, and then using how much is contaminated to evaluate possible future effects on the marine ecosystem. Since oil is less dense than water, it will float on the surface, and methods to measure oil amount can rely on this property. Water contamination by oil can be measured by five methods including ‘direct weight’ measurements, colorimetric, infrared (IR), ultraviolet (UV) fluorescence and particle-counting methods, which measure the top surface layer of the water. However, though technology is advanced, the exact number for oil amount cannot be determined as these all involve sampling methods, and not an absolute measure.

Oil spreads quickly, forming a top layer because of it being less dense, blocking out what’s under it. The main impact oil does it prevent aquatic plants from receiving ample sunlight and oxygen, which is required for photosynthesis and respiration respectively. Being unable to carry out biological processes, the ecosystem suffers immensely in death of species life.
To measure insolation that is received by plants after oil spills, light meters are used to take readings. However, though this is the most practical way to do so, light readings may not be entirely accurate because of the other conditions that affect including seasons, weather or time of day.

Dissolved oxygen is derived from the atmosphere and photosynthesis from aquatic plants. The top layer of oil impairs plants’ ability to photosynthesise, and to gain oxygen directly from the atmosphere at the water surface. Therefore, there is a pressing oxygen demand. We can measure the biochemical oxygen demand (BOD) through using a Dissolved Oxygen (DO) probe, and taking samples across five days (or more). However, this may not be entirely reliable as it can be dependent on what organisms and their densities (high organism densities would imply less oxygen when used up for respiration), or more plants may signify less oxygen depletion – both which will affect results’ validity.

Once again, we are sampling for both, as it is impossible to carry out an investigation for the entire area. Thus, there may be slight inaccuracies in measurements taken with random errors including human errors, and systematic, there may be problems with the equipment not calibrated properly. There is the assumption that one area measured is representative of all others, though this is not true as it has been found that oil concentrations can vary between areas. Both methods also require initial samples to be taken pre-oil spill in order for comparisons to be made. This may be difficult as not all places will have tests been conducted.

METHODS OF MEASURING CHANGES IN BIOTIC COMPONENTS OF ECOSYSTEM

Oil spills can contribute to higher abnormal growths of algae – which also can hinder the growth of other plant species in the future. Thus we can measure the increasing amount of algae growth in the marine ecosystem. This could be done by substrate sampling where random samples are taken from different quadrats, and what each quadrat is mostly covered in. Once again, this is sampling and may not be entirely representative of the vast area; however, more repeats can be done to increase results validity.

Since algae takes up most of the space in the marine ecosystem – it minimalizes other species’ ability to live, also thus reducing diversity. Therefore, algae could also be measured using the Simpson’s Diversity Index through sampling. This would give a more valid way of seeing how algae, a biotic factor, would directly affect the ecosystem in terms of diversity, rather than how much algae is covered. Looking at only what is covered at each substrate is limited, as we are unable to look at the ocean floor easily, and there is a large area from the ocean surface to ocean floor.

REFERENCES


http://www.vernier.com/resources/ibes.html
http://www.ehow.com/about_6127348_oil-affect-growth-aquatic-plant_.html
http://www.time.com/time/health/article/0,8599,1992454,00.html
http://www.touchoilandgas.com/comparing-water-measurement-methods-a7704-1.html


Landfills (OLIVIA)

PROS

  • A place where all rubbish can go is made, and therefore there is lesser littering and rubbish on the streets.

  • Landfills are buried once it is full, and so grass can be put over the top and be made into a park or a golf course or ski slopes, where the rubbish makes a base/ground.

  • Rubbish from landfills can sometimes be made into biomass or fertilizer.

  • Most new landfills are built as lined facility, with leachate collection and treatment on-site. So the rubbish stored there is seen to be safe and no harmful chemicals are released.

  • Methane gas can be collected at some landfills with the right resources and this can be used in making fuels.

  • Sometimes a factory that creates energy for electricity can be built on top, using the gasses and chemicals that are being created by the rubbish in the landfills. Therefore making electricity energy is “free”.



landfills1.jpg
landfills2.jpg

landfills3.jpg

CONS

  • Some landfills that are used today are not chemically treated and not lined and so this is unsafe to use as harmful chemicals can be released from the different kinds of rubbish decomposing.

  • There are a lot of harmful chemical wastes such as; batteries, that are mixed into all of this rubbish and therefore can be hazardous to health because these harmful chemicals released can find their ways into our drinking source.

  • Sometimes an odor can be smelt from the and this is very unattractive, this attracts other unwanted animals such as varmin and bears.

  • Methane gas can be released from the landfills even after it has been covered. This gas is flammable and therefore no fire is allowed anywhere near the site. Sometimes a golf course/park is made over it; if there is a spark it could start a fire.

  • More and more land is needed to place all of our rubbish and made into landfills and so our environment is being diminished of its natural plants and animal habitats.



METHODS TO MEASURE ABIOTIC FACTORS

  • Soil: The soil around the landfill may be disturbed and may cause changes in the PH and water capacity which may affect the environment and habitat. A way to measure this is through a PH meter that tests both the PH of the soil and the moisture, this may used to measure an environment close to the landfill but not directly outside the site. These two results can be compared and this will show if there was a change in PH and moisture and if there is, the conclusion can help prove that landfills are really bad for our environment.
  • Air pollution: The air around the landfill may be polluted with gases being released from the decomposition of the rubbish. The amount of air pollution can be tested by comparing two different sites, one around the landfill and one off the campus. Air pollution can be measured by an active sampling routine, this involves a the collection of samples from the different sites by pumping air into a vacuum sealed container, this air is then tested in labs and the results can be compared to show the differences and prove the landfill to be either polluting for our environment and minimal effect on it. Passive sampling is another way air pollution could be tested and this involves a cheaper routine, a diffusion tubes are set up that pumps in air from the outside and a chemical absorbent at the other. After, the chemical absorbent can then be tested in the labs. Another way could involve automatic sampling which uses a high-resolution measurements of a range of pollutants at a single point. The sample is measured on-line and in real-time, typically with 15-minute averages or better, with data being collected from individual monitoring sites by telemetry.

METHODS TO MEASURE BIOTIC FACTORS

  • Animals living in the soil: The soil can home many living things such as worms, ants and many types of plants. Also there are fungi and bacteria also living in the soil. The gases released from the landfill could chase away these living things or even kill them. To measure if the landfill is actually affecting this factor, we can take a sample of soil, one near the site and one away and compare nutrients and any living thing found. If more living things are found off the site then this could help our hypothesis that landfills are killing our environment diversity of plants and animals.
  • Plants: Plants near the site can be affected by the pollution and gases (once again) released from the landfills. The plants may be smaller or have less nutrients within it's stem. To measure this we could look at plants growing near the site and away, we could examine the stem size, leaf size, nutrients available to the plants around the area and the height and width of the plant. Comparing two different sites could show which site has bigger and healthier plants or not have any differences at all, which could once again help slow down the rate the landfills are being filled up.

  • Animals: Animals may be attracted by the stench the landfill gives off, the animals could be harmed by eating the unsanitary rubbish. The amount of animals in the area could be measured by doing a sitting test. This involves sitting, watching and counting how many animals appear around the landfill or in the landfill. This could be compared against another site where the environment has lesser rubbish in it's surroundings.


SOURCES AND REFERENCES


http://www.news-around-the-world.com/news-of-the-day/county-fights-waste-dumped-in-landfill/
http://answers.yahoo.com/question/index?qid=20081005134527AAvr32j
http://www.treehugger.com/files/2009/03/what-really-happens-at-a-landfill.php
http://www.rhorii.com/MVShoreline/MVShoreline.html
http://www.nodumpconecuhcounty.com/what_is_a_landfill.html
http://www.ottawaskeptics.org/the-reality-check/62-episodes/233-the-reality-check-41-landfills-chelation-safety-in-numbers
http://www.docstoc.com/docs/22901886/Abiotic-and-Biotic-Factors-in-Soil
http://www.pasco.com/biology/ecology/abiotic-biotic-environments.cfm
http://scienceaid.co.uk/biology/ecology/studying.html
http://www.swansea.airqualitydata.com/cgi-bin/faqs.cgi?3


landfills4.jpg








Well done Olivia, you have evaluated landfills very well through your pros and cons approach. And you have made a great start for the team! :-)
However, have a re-read of the task... i realise that deciphering the task is probably the hardest part!

You need to:
Describe and evaluate the methods for measuring changes in abiotic and biotic components of an ecosystem due to a specific human activity.

That means, what methods could be used to measure any changes as a result of disturbance due to a landfill?
And what are the strengths and weaknesses of those methods?

This task is really related to the sampling methods you learned at Tioman, and other methods for measuring abiotic factors that you can find through research, after thinking about what might be an appropriate way to compare a disturbed versus undisturbed site due to a landfill.
In that sense, the task is also a bit similar to the in-class Planning task, but that you are able to research instead.
It relates also to the idea of EIA`s in that these are the kinds of methods that could be employed to monitor change in the environment (or a specified ecosystem/s) due to a human activity.

Some possible examples of methods that could be used to measure the effect of a landfill on the abiotic and biotic components of an ecosystem might be ->

A method for measuring abiotic & biotic factors in soil, check out this link: http://www.docstoc.com/docs/22901886/Abiotic-and-Biotic-Factors-in-Soil
(You would then need to describe this method in your own words and evaluate the pros and cons of it).
Here is a more general link, that may be applicable to more than one students` study: http://www.pasco.com/biology/ecology/abiotic-biotic-environments.cfm
And another link, through measurement and sampling: http://scienceaid.co.uk/biology/ecology/studying.html
A great number of methods are given here, for measuring abiotic factors by using dataloggers and probes: http://www.vernier.com/resources/ibes.html

Here`s a suggestion for Olivia. If you were to focus on The impact of a new landfill on a nearby lake, for example.
An abiotic factor you could measure could be biochemical oxygen demand (B.O.D.) - the method for measuring it is given in the vernier link above.
It could be used for monitoring change in BOD in the lake before the landfill is created and then again when the landfill is operational.
A biotic factor you could measure could be the diversity of plant life on the landfill side of the lake. You could then choose a sampling method involving quadrats and describe and evaluate that for strengths and weaknesses also.

I think that for everybody, if you can choose one abiotic factor (eg. pH) and one biotic factor (eg. plant life) and then find methods for measuring these things.
Work out how those methods could be used to measure changes in an ecosystem that is being impacted by the human activity you have chosen, and describe the methods and how they are useful for measuring such change.
Then, evaluate the methods - what are the pros and cons of them for that purpose.

Thank you Olivia for getting your work up here first :-)
It has hopefully provided a learning opportunity not only for yourself, but for your class mates also.
Well done.
Good luck everybody, I`ll look forward to seeing them all posted here by the end of this weekend.
Regards,
Mrs S


22/11/2010

1.1.1 Economic, Social and Value Systems



ECOLOGICAL PYRAMIDS (Adele, Shireen and Shannon)

Number pyramids are those which represent the number of each species. Advantages are that it gives a visual representation of the population of each species in comparison with that of the other species and is easy to read. Disadvantages are that it may be misleading as it shows how there are often many more consumers than producers, making the pyramid look imbalanced, and not that the weight of the producers is a lot higher and many consumers may feed on one producers. Also, it does not show the relative size of the organisms. Also, the data is from a single fixed period of time and may change.

Biomass pyramids represent the weight of each species. Advantages are that they may provide an explanation for the feeding habits and visually show how many consumers may feed on one producer. Disadvantages are that it is not very detailed and only focuses on one aspect of the ecosystem. Also, the data is from a single fixed period of time and may change.

Energy pyramids (pyramids of productivity) represent the energy content at each trophic level. The advantages of this model are that it gives a very clear visual representation of how much energy is lost at each trophic level. Also, they show the flow of energy over time (more accurate). Disadvantages are that it does not show how the energy is lost and only has data for energy. Another disadvantage is that it is more difficult to collect data for an energy pyramid because it needs to be collected over a long period of time.

A disadvantage of all types of pyramids is that they have difficulty with where to place organisms that feed at more than one trophic level (e.g. humans who may feed at primary, secondary or tertiary)


Ecological_Pyramids.png

(A disadvantage of the above is that it does not contain numbers and therefore is only useful for understanding, not actual use)


TO DO: PAGE 52 (Olivia and Paula)

1. How many trophic levels are in this food chain?
There are 3 trophic levels in this food chain.
2. How many times more concentrated is the DDT in the body of cormorant than in the water? Explain how this happens?
The cormorant has a concentration of 26.4% of the chemical, DDT. This happened because the cormorant ate lots of fishes which already had DDT in them from eating the plankton. So Biomagnification happened in the cormorant.
3. In which species does Bioaccumulation occur?
Bioaccumulation occurs in all of the species on every trophic levels of the food chain. Bioaccumulation is when a chemical, such as DDT is accumulated in the body of a species over time.
4. In which species does Biomagnification occur?
Biomagnification occurs in the second and third trophic levels. Biomagnification is when the amount of a chemical increases in each trophic level. In other words the amount of DDT in this food chain is 'magnified' when we get closer to the top of the food chain.

Bioaccumulation and Biomagnification
  • DDT: A type of chemical pesticide, not biodegradable
  • Bioaccumulation: As a chemical is suddenly placed in an environment and broken down, plants take in the chemicals and animals breath it in or ingest it. This may lead to disease of death if they do not excrete it, as it builds up in their bodies over time.
  • Biomagnification: When a herbivore eats a plant that has chemical in it's tissue, it's chemical intake would be higher than a single plant took it because a herbivore eats many plants over time. It goes the same for carnivores that eat the herbivores because they eat many herbivores over time that have eaten the plants full of chemicals.
  • Trophic efficiency: Only 10% of energy from one trophic level is passed on to the next. The rest of the energy is lost through heat and respiration.