Threatened Ecosystems  

Introduction

The aims of this project are:

  • To help students and other users to explore an ecosystem and to try to get an answer to the crucial question: "Is our ecosystem feeling well?"
  • To link students all over the planet in production of a common electronic educational material. They follow a manual of research in an ecosystem nearby, publish their results and they have access to information from all around the globe.
  • To raise the public awareness of the health of different areas, of environmental problems and of human impact on the environment.
  • To do this by means of practical investigation and personal involvement.

Guidelines

  • Read the manual below
  • Select an ecosystem for an investigation.
  • Go there! Indentify, compare and describe - plants and vegetation, fauna in the air, on the ground, in ponds and streams etc.. Take samples and analyse them in school afterwards.
  • Sum up results and report your investigation directly on a mobile phone (http://schoolweb.se/threatened/phone.htm) or print the form (click here) and report later to the database. You get an opinion about the health of the area by adding plus (+) and minus (-)
  • Compare your ecosystem with other areas over Internet.

Things you will need

- Guide to plants and animals
- Thermometer,
- Ruler or measure,
- Indicatorpaper (pH 2,5-10),
- Distilled or deionised water
- Filterpaper
- A syringe 2 ml
- A spade or table-spoon to take soil samples
- A teaspoon 5 ml 
- Plastic bag to bring samples of soil or vegetation back to laboratory
- Plastic or glass bottle to bring water-samples back to school. Rinse the bottle with the water sample. Don't use any detergent or washing up liquid. Then fill the bottle to the top (no air at the top).

 

Reagent preparations

- hydrochloric solution 0,020 M HCl ( 0,020 N HCl )

- mixed indicator solution Dissolve 0.06g Bromcresol green and 0.04 g methyl red in 100 ml ethanol. bromcresol green-methyl red, The mixed indicator goes through a series of color changes from blue to an end point color of pink.

 

I.   Address of the ecosystem

 

 

 Country 
  Region 
  Name of your city or village
  Name of your school or organisation
  Your email-address 
(just for registration; will not be published)

II. Description of the area

  Month of research
Area of research (hectares, acres or sq.m)
     
  Type of forest
  • Evergreen forest
  • Deciduous forest
  • Mixture Evergreen/Deciduous forest
  General observations of the terrestrial part (rainy period or drought, soil quality, tidal area or not, paddy field, swamp, elevation above mean sea level, gradient, vegetation plants, trees, land use) 
Most characteristic field-plants
Field vegetation is more dynamic than trees. 
Reproductive maturity is reached earlier, the life span is shorter and the dependence on environmental factors (such as pH and nitrate) seems to be grater.
Death of herbaceous vegetation beneath affected trees is a warning sign.
No. of different types of trees in researched area
No. different species of higher plants in researched area
  Birds species observed
   
Soil pH
Soil pH above 7 indicates a risk of alkalinity; around 7 indicates soil is neutral; below 7 indicates a risk of acidification.
Changes in the acid-base properties of soil are followed by several other chemical and biological changes.
Ground 
  • Weigh an empty ceramic bowl.
  • Add 5,0 gram of fresh soil to the ceramic bowl.
  • Let the fresh soil dry over night or at least 6 h in an oven (+105oC).
  • Cover the bowl and let it become room-tempered before weighing again.
Ceramic bowl (empty)

g

Ceramic bowl + fresh soil

g

Fresh soil (f)

g

After drying
Ceramic bowl + dried soil

g

Dried soil (t)

g

Content of water
 100*(f-t)/f

%

 
Content of organics (%)
  • Use the soil-sample from above
  • Heat the ceramic bowl up to +600oC or burn it using a gas jet until there is nothing but sand left.
  • Cover the bowl and let it become room-tempered before weighing again.
Ceramic bowl + sand

g

sand (s)

g

Content of organics
100*(t-s)/f		 %
Content of sand
100*s/f		 %

 

Report Soil-content of water + organics + sand (i.e. 35% + 44% +21%)
   

Field activity

  • The approach to the sampling site must be easy and safe.
  • Samples must not be collected from stagnant water 
  • Note date and time of sampling.
  • Observe and record the surroundings around the site of sampling.
    • Vegetation and animals in the water and on land.
    • Collapse of river beds
      Industrial activities (mining etc)
      Human activity around (fishing, drinking, boating, washing)                                                            
    • Bedrock and soil surface on land.
    • Water - colour, odour etc
  • Give the site of sampling a name.
  • Samples should be taken a bit from the 'landedge' (for example tie a bottle to the end of a long stick

 

  General observations of the aquatic part
(rainy period or drought, width, depth, bottom material, soil around, water flow, borders, colours, salinity, how is the wetland used) 
     
  Temperature
 

Variations in water temperature profoundly affects the aquatic life. At higher temperatures gases like oxygen dissolve to a lower extent than in cool water. Aquatic animals are affected by this as they are weakened by the less availability of oxygen. Plants on the other hand grow better with raise in temperature. The water temperature during drought is normally higher than during the rainy period, because during a drought the water level is low and solar penetration is high so that the water temperature becomes high. The water temperature can also get raised due to both natural and human factors.

This test has to be done immediately after collecting the sample. Keep the thermometer dipped for sufficient time before constant at a reading.

   
  Benthic fauna (including insects on water surface) 
 

plankton net  Useful in many aquatic areas - to collect micro-organisms in water.  If you can't find a plankton net in your school try to make one yourself (see Figure)

  1. Small plastic jar  - put a stone inside the jar (easier for the net to get under the water surface

  2. rubber band

  3. fine-meshed net 'nylon stockings'

  4. plastic strings

     
  Pollution degree ( A - E )
Estimating the degree of pollution includes a study of the fauna because it indicates how stable or strained the ecosystem is.
 

 Pollution degree

 

 A
 Clean and pure water
 with 'normal' fish stock and lot of mini-beasts

 B
 Water pollution due to diesel fuels and oils 

 C
 Change of temperature
 Fish migration

 D
 Filthy water i.e. from “slurry” or acid mine drainage
 with reduced fish stocks, spare occurence of mini-beasts, dead animals and dead vegetation

 E
 Heavily polluted water with no life at all
 no fish, no mini-beasts, no water vegetation

 

     
  Water pH
  This indicates how acid or alkaline the water is. An acid solution has a pH value less than 7. An alkaline solution has a value of more than 7. A solution of pH 5  is 10 times more acid than a solution of pH 6.

Some natural waters range from pH 4 up to pH 9 and are often slightly basic due to the presence of carbonates and bicarbonates. A major deviation from the normal pH for a given water indicates the intrusion of strongly acidic or strongly basic industrial wastes.

pH can range widely due to addition of wastes from industries and cities but also from the photosyntetic activity in the water itself. During the assimilation period (daytime) carbondioxide is consumed and water pH is slightly increased. Nighttime, when there is no assimilation, organisms are breathing. Carbondioxide is produced and pH is lowered.

In healthy wetlands microbes (bacterias) try to keep wasted metal-ions at acceptable levels. When pH is low the amount of metal-ions are increased in the water because microbes loose their ability or they die. 

  • indicator strip or paper  With dry hands tear a strip from a pH paper roll and dip one end of the strip into the water briefly. Then compare the colour developed on the wet portion of the strip with the colour shart printed on the cover of the paper roll.

  

     
Alkalinity mmol bicarbonate per litre
  • <0,16 mmol bicarbonate per litre
  • 0.17-0,49 mmol bicarbonate per litre
  • >0,50 mmol bicarbonate per litre
 

Alkalinity or acid-consuming capacity is a measure of the capacity of water to neutralize acids. It's due to the presence of bicarbonate (HCO3-), carbonate(CO32-) and hydroxide-ions (OH-).  Bicarbonate is the major form of alkalinity. Carbonate and hydroxide may be significant when algal activity is high and in certain water and wastewater, such as boiler water. 
Total alkalinity is determined by titration to a pH of 5,4 depending on the amount of carbon dioxide present.
At pH=5,4 or lower Alkalinity is null
If acids are added to a water with pH<5,4 the pH of the water is lowered.
If acids are added to a water with pH>5,4 then the pH will stay constant but the amount of bicarbonate will be lowered.

Technique

  1. Put a 20 ml (4 tsp) sample in a beaker. Add 1 drop of a mixed indicator solution to the sample. The color of the sample is blue
  2. Fill a 2 ml syringe with 0,020 M HCl (20 mmol/l HCl)
  3. Add HCl in drops from the syringe and stir the sample until the indicator changes from blue to an end point color of pink.
  4. Note the added amount of acid v ml and count the alkalinity or the concentration of bicarbonate.
  5. Alkalinity = 20* v/ 20
  6. If v < 0,2 ml the capacity of water to neutralize acids is low (A < 0,17mmol/litre), if v > 0,6 ml the capacity is high ( A > 0,6 mmol/litre )
     
  Suspended solids
  Solids may affect the water quality adversely in a number of ways. Outside sources that can affect the natural balance of total solids include urban runoff like fertilizers from residential agricultural use (mainly phosphates and nitrates). Sources that can affect the level of suspended solids are leaves and other plant material, suspended sediments (clay particles) from urban runoff and soil erosion and decayed plants and aimal matter.
High concentration of suspended solids reduces water clarity, contributes to decrease in photosynthesis; binds with toxic compounds and heavy metals; and leads to increase in water temperature through greater absorption of sunlight by surface water.

No
residue

Low
residue

High
residue

Very high residue

 Method
 1. Filter 100 ml sample through a funnel lined with a filter paper
 2. Allow the filter paper to dry
 3. Unfold the dry filter paper and observe it for any retained solid.
 4. Record the observation

     
  Conductivity (mS/m)  
 

Conductivity is a measure of the ability of water to pass an electrical current. Conductivity in water is affected by the presence of inorganic dissolved solids ions that carry a negative charge or ions that carry a positive charge. Organic compounds like oil, phenol, alcohol, and sugar would lower the conductivity. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. For this reason, conductivity is reported as conductivity at 25 degrees Celsius (+25oC).

Conductivity in a streaming water is affected primarily by the geology of the area through which the water flows. Streams that run through areas with granite bedrock tend to have lower conductivity because granite is composed of more inert materials that do not ionize (dissolve into ionic components) when washed into the water. On the other hand, streams that run through areas with clay soils tend to have higher conductivity because of the presence of materials that ionize when washed into the water. Ground water inflows can have the same effects depending on the bedrock they flow through.

The basic unit of measurement of conductivity is the mho or siemens. Conductivity is measured in millimhos per meter (mmhos/cm) or millisiemens per meter (µS/cm). Distilled water has a conductivity in the range of 0,05 to 0,3 mS/m. The conductivity of rivers generally ranges from 5 to 150 mS/m. Studies of inland fresh waters indicate that streams supporting good mixed fisheries have a range between 15 and 50 mS/m. Conductivity outside this range could indicate that the water is not suitable for certain species of fish or macroinvertebrates. Industrial waters can range as high as 1,000 mS/m.

 

Procedure

Conductivity is measured with an ohm-meter with a cell consisting of two electrodes (in fixed distance of a m). The cell is dipped into a water sample. 

Since the conductivity varies with temperature, the measurements are always related to a reference temperature (+25oC).

Measure the condutivity in b ohm and the result is given mS/m  ( S=1/ohm and mS=1000/ohm)

 Conductivity

= 

   _1000_
    (b*a)
     
  Turbidity
  • Clear water
  • Turbid water
  • Some turbidity
 

This is the result of fine solids in the water. These solids can be in form of sand, industrial wastes and sewage contributed by soil, industrial and urban discharges.

Oil which does not settle down and floats on the surface as a milky white film cuts the sunlight reaching the water body. Thus transparency decreases the light penetrating into the water, which in turn reduces the photosynthetic ativity of plants. Heavy solid particles settle down and smother organisms at the river bottom.

 


The transparency is measured with help of a Secchi disk, based on the visibility of an object in water is an approximation.

secchi-disc  White metallic disc - any hard and heavy material, circular or rectangular shape (see right) - designed for the measurement of the clarity of a body of water. The disk is tied with a string at the center and coloured white.  The disc is lowered into the water on a graduated line until it disappears from view. The depth at which the disc is no longer visible is recorded - a rough limit of the visibility or transparency.

aqua-scope for secchi-disc readings, aquatic plant and animal observations ( the red thing in the picture; could be a see-through-pipe with or without a piece of glass or similar at the bottom)

     
  Smell
  • No smell
  • Smell of hydrocarbons (oil, petrol...)
  • Smell of hydrogensulfide
  • Other smell (mot identified)
     
  True colour (ocular inspection)
  • Virtually colourless
  • muddy
  • discoloured
     
  Other observations/analyses (diseases related to the environment in humans, domestic animals, fish etc.)
     
 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

© Hans Willstedt, Lyceum of Vaxjo,  Sweden. Revised: 04 06, 2007