The C.C.C. Ming Yin CollegeThe C.C.C. Ming Yin College

19 / 1 / 200619 / 1 / 2006

IntroductionIntroductionAimsAims1.1. To compare the biodiversities To compare the biodiversities

at site A and site B. at site A and site B.

2.2. To promote our To promote our environmental awareness. environmental awareness.

Locations of Site A & Locations of Site A & Site BSite B

Profile of Site AProfile of Site A

The Profile of Site A

-40

-30

-20

-10

0

Dis

tance

alo

ng 0.3

0.7

1.1

1.5

1.9

2.3

2.7

WaterDepth/ cm

Profile Profile ofof Site B Site B

The Profile of Site B

-14

-12

-10

-8

-6

-4

-2

0

Dis

tan

ce

alo

ng 0.3

0.7

1.1

1.5

1.9

2.3

2.7

WaterDepth/ cm

Site ASite A

Site ASite A

1. The area is shaded by canopy of trees.

2. Light intensity is low.3. Fallen leaves can be found.4. The sediment is mainly composed

of sandstones.5. The water is clear.6. Slow waterflow.

Site BSite B

Site BSite B1. Large number of stones with diffe

rent sizes lie at the bottom of the stream.

2. Fast waterflow.3. Aquatic animals are rarely seen.4. Adequate sunlight.5. Cool but not windy.

Water SamplingWater SamplingSite ASite A Site BSite B

1. Ammonia Content (pp1. Ammonia Content (ppm)m)

0.1670.167 0.1000.100

2. Phosphate Content (pp2. Phosphate Content (ppm)m)

2828 66

3. pH3. pH 7.07.0 6.846.84

4. Total Dissolved Solids 4. Total Dissolved Solids (ppm)(ppm)

0.520.52 0.520.52

Site ASite A Site BSite B

5. Total Suspended 5. Total Suspended Solids (mg/l)Solids (mg/l)

88 //

6. Dissolved Oxygen 6. Dissolved Oxygen (mg/l)(mg/l)

5.515.51 4.784.78

7. Chemical Oxygen 7. Chemical Oxygen Demand (mg/l)Demand (mg/l)

// 2.802.80

1. 1. Suspended solid particles of the water samSuspended solid particles of the water sample cannot be determined in site B.ple cannot be determined in site B.

Reason:Reason: Water vapour in the air was absorbed by the filter paper before weighing yesterday.

2. 2. Chemical oxygen demand of the water samChemical oxygen demand of the water sample cannot be determined in site A.ple cannot be determined in site A.

Reason: Personal error. Too much permanganate solution was added after end point was reached.

Physical FactorsPhysical FactorsSite A Site A Site BSite B

Light IntensityLight Intensity SurfaceSurface 0.50.5 5.55.5

BottomBottom 0.50.5 4.54.5

Water Water TemperatureTemperature

SurfaceSurface 19.319.3 19.319.3

BottomBottom 19.319.3 19.119.1

Average Flow RateAverage Flow Rate 0.1 m/s0.1 m/s 30 m/s30 m/s

Freshwater PlantsFreshwater Plants

Site ASite ANameName Approx. DensityApprox. Density

Taro Taro 芋芋 77

Sweet FlagSweet Flag 石菖蒲石菖蒲 22

All the plants found in Site A and Site B are different.

Site BSite BNameName Arbitrary Arbitrary

UnitUnit

Day-flowerDay-flower 竹節草竹節草 11

Water Celery Water Celery 水芹水芹 11

Water CressWater Cress 西洋菜西洋菜 22

GreaterduckweedGreaterduckweed 浮萍浮萍 100100

MossMoss 蘚蘚 11

Freshwater AnimalsFreshwater AnimalsSite ASite A Site BSite BApprox. Approx. DensityDensity

Approx. Approx. DensityDensity

Mayfly NymphMayfly Nymph蜉蝣若蟲蜉蝣若蟲

11 33

Large Stream SnailLarge Stream Snail海南蜷螺海南蜷螺

2222 00

Viviparous SnailViviparous Snail石田螺石田螺

00 1212

Site ASite A Site BSite BApprox. DenApprox. Den

sitysityApprox. Approx. DensityDensity

Dragonfly Nymph Dragonfly Nymph 蜻蜓若蟲蜻蜓若蟲

00 11

Small Stream Leech Small Stream Leech 舌蛭舌蛭

11 11

Ranshorn Snail Ranshorn Snail 凸旋螺凸旋螺

00 1212

Site ASite A Site BSite BApprox. Approx. DensityDensity

Approx. Approx. DensityDensity

Damsefly NymphDamsefly Nymph豆娘若蟲豆娘若蟲

00 22

HK NewtHK Newt香港瘰螈香港瘰螈

22 11

Reservoir SnailReservoir Snail瘤擬黑螺瘤擬黑螺

88 11

GobyGoby鰕虎魚鰕虎魚

33 00

Comparison for the number of Comparison for the number of organisms and the biodiversity organisms and the biodiversity in site A and site Bin site A and site B

‧Plants

In general, there are fewer plant species in site A than in site B. However, the total numbers of plants in the two sites are about the same. A total of 9 plants can be found in site A and a total of 10 plants can be found in site B. There is no common plant in the two sites.

A total of 2 plant species can be found in site A, namely, taro and sweet flag. Taro is the dominant species in site A, 7 of which can be found. Only 2 sweet flags can be found.

A total of 5 plant species can be found in site B, namely, day-flower, water celery, water cress, greaterduckweed and moss. Greaterduckweed is the dominant species in site B, 5 of which can be found. While for the other species, only 1 or 2 of which can be found.

Site A has a large tree, so there is a large canopy and less sunlight can reach the freshwater. Plants can’t get enough light for photosynthesis so that there are little freshwater plants. There are only Taro and Sweet Flag.

Site B is exposed to sunlight directly so there are many different species of short freshwater plants in site B such as Day-flower, Water Celery, Water Cress, Greaterduckweed and Moss.

‧Animals

In general, there are fewer animal species in site A than in site B. However, there are slightly more animals in site A than in site B.A total of 37 animals can be found in site A and a total of 33 animals can be found in site B. Mayfly nymph, small stream leech, Hong Kong newt and reservoir snail are found in both sites.

A total of 6 animal species can be found in site A, namely, mayfly nymph, large stream snail, small stream leech, Hong Kong newt, reservoir snail and goby. Large stream snail is the dominant species in site A, 22 of which can be found. Reservoir snails are the second most abundant organisms in site A, 8 of which can be found. For the other species, only 1-3 of which one can be found.

A total of 8 animal species can be found in site B, namely, mayfly nymph, viviparous snail, dragonfly nymph, small stream leech, ranshorn snail, damsefly nymph, Hong Kong newt and reservoir snail. Viviparous snail and ranshorn snail are the dominant species in site B, 12 of each of which can be found. For the other species, only 1-3 of which can be found.

At site A, the phosphate content in the water is much higher than that at site B due to inorganic fertilizer used by farmers nearby and slow water flow rate. Phosphate accumulates. The high phosphate content favours the growth of photoplankton. The slippery stone surfaces indicate the large population of photoplankton.

The animal found in site A is mainly snails, a kind of filter feeder which feeds on photoplankton. As there is plenty of food, the growth of snail population is favoured.

Reasons why site A has larger Reasons why site A has larger number of each species while number of each species while site B has greater diversity of site B has greater diversity of organismsorganisms

The physical environment in The physical environment in these 2 sites are different these 2 sites are different because:because:1.The huge canopy of a tree covers

the surface of the stream, reducing light intensity reaching the stream.

2.The fallen leaves of a tree increase the nutrients available in the stream since they can be decomposed, releasing ammonia and phosphate.

3. The roots of the trees anchor the soil particles tightly, preventing soil erosion.

4. Mosses can secrete acid, breaking down large rocks into smaller soil particles.

5. When the dead bodies of living organisms such as insects decompose, it leads to an increase in nutrients available in the stream.

Photos From Photos From Polluted AreaPolluted Area

Reflections from Reflections from polluted areapolluted area

Water in polluted area is smelly, turbid and still. A lot of rubbish can be found, such as tyres, glass, plastic bottles and suspended organic substances.

The government should construct sewage pipes to collect and treat household sewage before discharge.

People lack awareness of environmental protection that should be raised by the government through education.

The government should set up laws and impose heavy fines on those who discharge untreated sewage into rivers directly.

Limitations of this field stuLimitations of this field studydy• Time of investigationTime of investigation Since the investigation in this field

study only covers a particular season(namely, winter), we are not allowed to obtain a full picture of the ecology of the two sites(site A and site B) throughout the year and we may not understand the whole thing thoroughly. For instance, a certain kind of organism may be active in summer, but not in winter.

• Lack of sophisticated apparatus and skills Lack of sophisticated apparatus and skills to use themto use them

Since we do not have sophisticated apparatus and the skills to use them, some factors and organisms of the field cannot be studied. For instance, we cannot count the number of micro-organisms, such as bacteria and fungi in the stream and we cannot study them thoroughly.

• Changing environmentChanging environment The reading varies from time to time The reading varies from time to time

shows that the environment is changing. shows that the environment is changing.

ConclusionConclusion After this field study, we can see that the

organisms and the environment are interacting with each other continuously and form a stable ecosystem.

For instance, the canopies of the tree affects the light intensity on the water surface and at the bottom, thus affecting the organisms.

Moreover, human activity has adverse effect on the ecosystem. For example, household sewage directly discharged into the stream and the dumped inorganic fertilisers increase the phosphate content in water.

ImprovementsImprovements1)For constrasting sites,we should avoid choosing

somewhere just near other groups ,e.g. a bit lower position so the results will not be so easier affected by other groups' working.

2)We should have a better group coordination before collecting data at the stream and doing experiments in order to a better job allocation.

3)We should have more preparation e.g. finding more information about organisms in stream and the ways to proper use of apparatus before going the field trip.

Our feedbackOur feedbackWe are glad that we learn many things and gain

many valuable experiences from this field trip. Firstly, it a great chance for us to contact with nature.

We know more about the ecosystem of stream. We can also practise some skills learning from books. Moreover, we can use many modern apparatus which are not available in school laboratory.

The trip also help us to know our weaknesses---poor job allocation and presentation skills. To improve this situation, we will try the best to have a better communication and have a rehearsal before presentation.

All in all , the trip help us in both academic and personality development. It's a precious memory for us.

We were collecting those data we needed.

It is the first time for us to see a Hong Kong Newt .

Every one of us actively participated in the Field Study to collect data and samples.

Group Members ListGroup Members ListSite ASite A

Chan Kwing LamChan Kwing LamChu Ho ShingChu Ho Shing

Lam Chung KwunLam Chung KwunChu Nim ChiChu Nim Chi

Li Pui SzeLi Pui SzeLo Lai PingLo Lai Ping

Site BSite B

Chan Sze ChunChan Sze ChunHo Kin TakHo Kin TakLi Pui SunLi Pui Sun

Tse Yuet SimTse Yuet SimYeung Pui ShanYeung Pui Shan