Erken Laboratory
The quality of rivers and streams from
Lake Erken to the Baltic Sea
Research in limnology
Natalia Biała, Poland
Jānis Burvis, Latvia
Supervisor: Karin Beronius
2009, Sweden
ABSTRACT .............................................................................................................................. 3
INTRODUCTION .................................................................................................................... 4
AIM ......................................................................................................................................... 5
HYPOTHESIS ............................................................................................................................ 5
MATERIALS AND METHODS............................................................................................. 6
MATERIALS ............................................................................................................................. 6
METHODS ................................................................................................................................ 6
RESULTS.................................................................................................................................. 9
DISCUSSION ......................................................................................................................... 12
CONCLUSION ....................................................................................................................... 16
REFERENCES ....................................................................................................................... 17
2
ABSTRACT
In our work we focused on examinating water quality in rivers and then comparing the results
to results from Lake Erken. Using different equipment and methods such as kick and catch
method, small strainers method and taking animals from rocks method we collected different
species and estimate ASPT values. We also measured the abiotic factors – temperature, pH,
total phosphorus and stream speed. The ASPT values in rivers varied from 2.5 to 7.5 and
average value for rivers were almost the same as ASPT value in Lake Erken. Our hypothesis
“As the surrounding areas have a big effect on water quality in streams, 1 the ASPT-index will
decrease at each site, travelling from the outlet of Lake Erken towards the Baltic Sea.” was
true so it means that surrounding area affects water reservoirs. Also parameters were as we
expected from ASPT values so we can say we did our work very well. But we cannot say that
our hypotheses are completely true, because only half of them are true. And our work should
be continued because there are a lot of factors to measure and see how they affect the
environment.
1
The Erken report. Limnologi MN1. 2007
3
INTRODUCTION
Rivers are a water reservoir over the earth surface. The water in the river is not stable but it
flows usually from mountains, lakes or other sources to a sea. Due to the fact that rivers often
flow through areas where people live and work the water in rivers contain a lot of substances
that come from households, fields, pastures etc. These substances can make abiotic factors
(like temperature, pH, oxygen condition and nutrients) different in different sites of river.
Above-mentioned substances can also prevent some species of macroinvertebrates from
existing so that the value of ASPT- index will be different depending on the level of pollution.
If the value of ASPT index is high it shows that the water quality is good, and a low value
indicates a worse water quality. 2
In streams and rivers we can find a lot of different species of plants (for instance Fontinalis
spp., Rhyncostegium riparioides or Blindia acuta), algaes, which are the primary producers in
most of streams and rivers. Mostly algae occurre as tufts on rocks. Most of them are
microscopic, but they can also occurre in colonies forming visible layers on the substrate.
As well as plants there are a lot of animals (for instance larvae of many insects, mayflies,
stoneflies, caddis flies and also microbes and even a few species of fish). Apart from above
mentioned invertebrates and vertebrates you can find a lot of other kind of living creatures
like microorganisms for example bacteria (which are known to be sensitive to low pH) and
fungi.3
We chose five places from Lake Erken to Baltic Sea. These places are located between lakes
in the area. There are different surroundings around chosen places like roads, countryside,
farms, fields, pastures and forests. We measured water quality in running water as well as in
pools. We were aware of possible differences between results from pools4 and running water5
due to the information we have read before. 6
2
Armitage P.D., Moss D., Wright J.F., Furse M.T. 2005. The performance of a new biological water quality
score system based on macroinvertebrates over a wide range of unpolluted running-water sites.1982
3
The biology of streams and rivers. In: Life in running water
4
http://en.wikipedia.org/wiki/Stream_pool
5
http://en.wikipedia.org/wiki/Stream
The biology of streams and rivers. In: Life in running water
6
4
AIM
The aim of our project was to find out if people and animals living near the rivers have any
influence on the river water contents and quality. We examined composition of water and
animals that live in the rivers. We compared the river water to the lake water to find out how
people, animals and infrastructure affect river water quality. We also compared our results to
results from previous examinations7, to see if water quality has somehow changed during past
years. During our project we used different methods and materials to collect as many data as
possible.
HYPOTHESIS

If the water flows from lake to the sea through rivers located in areas where people
and animals live and where infrastructure is developed, then the abiotic factors
(temperature, pH and total phosphorus) in river water are higher than the water in the
Lake Erken.

As the surrounding areas have a big effect on water quality in streams, 8 the ASPTindex will decrease at each site, travelling from the outlet of Lake Erken towards the
Baltic Sea.

Due to the fact that water in pools is almost still 9 the ASPT index and water quality
will be lower than it is in flowing water – riffles.
7
Penka A., Tamm M.H., Benthic animals as indicators: from Lake Erken to the Baltic Sea, 2008
The Erken report. Limnologi MN1. 2007
9
http://en.wikipedia.org/wiki/Stream_pool
8
5
MATERIALS AND METHODS
MATERIALS
During our fieldwork and in lab we will need some equipment which are described here:
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waders (2)
small strainers (2)
long strainers (2)
plastic jars (30)
measuring line (1)
orange (1)
timer (1)
pH meter (1)
thermometer (1)
tweezers (2)
bowl (2)
plastic bottles (10)
pipette (2)
microscope (2)
Books/guides for indicating species/animals
METHODS
For our fieldwork, which we did from June 22nd to June 24th 2009, we chose five places
located in the area between Lake Erken and the Baltic Sea to examine (the river near the
crossroads located close to the city Rönnsbol, the river near the crossroads close to Roslags –
Bro, in the middle of river Broströmmen near Getingarne, the river Broströmmen flowing into
the lake Gillfjärden and the river connecting the lake Gillfjärden and Norrtäljeviken (place
between Runsten and Hårnackalund)).
At each site we were looking for both pools and running water. At each of those points we
chose ten meters for taking samples, which we divided with six points (two meters between
each point). At each of those points we took samples from water near to shore and in middle
of river using methods described below. Also we measured abiotic factors like temperature,
pH and total phosphorus.
DIRECTION OF FLOW
RIVER
2m
10m
6
1) The kick and catch method
Using waders, you step into the water and stand in a marked and selected area. You then place
the long strainer against the bottom and start to kick the bottom in front of it. It is important
that you stand in the direction of the flow in accordance to catch the animals that are detached
from the bottom. Depending on the abundance of animals you adjust the time for kicking.
You will then take up the strainer, turn it inside out into a larger bowl and pick all the animals
out and place them into small jars with lids.
We chose to kick for 3 minutes and to do 5 kick samples at each site distributed over 10 m
(see figure).
2) Taking samples with small strainers
Using waders, you step into the water and stand in a marked and selected area. Then you take
small strainer. It is important that you stand in the direction of the flow. Then you put strainer
in water and walk for two meters, which are marked area. Then you will take your strainer out
of the water and pick all the animals using tweezers out and place them into small jars with
lids.
3) Finding animals that lives underneath and upon of the rocks.
Using waders, you step into the water and stand in a marked and selected area. You need to
find the rock you want to examine, take it out of the water and turn it upside-down. Using
tweezers put all animals that you can see into plastic jars filled with water.
4) Measure the speed of water
Two people are needed to perform the method. Using waders one of you step into the water in
a marked and selected area. You need to hold the meter line at beginning of the line and let
your partner hold the end of the line. It is important that you hold the meter line in the
direction of the flow. Then you need to put the orange at the beginning of line into water and
start the timer. After the orange reaches the end of the line you need to stop timer. Then put
down the result.
5) Abiotic factors

Temperature:
Using waders one of you step into the water in a marked and selected area. You need
to put the thermometer into water and wait until it shows the result. Then take out the
thermometer and write down the result.
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pH meter:
Using waders one of you step into the water in a marked and selected area. You need
to calibrate pH meter. Then take the rubber lid of the electrode and put the electrode
7
under the surface. When results stabilized take the pH meter out of water and write the
results down.

Total phosphorus:
For this you will need plastic bottles to collect water samples. You must go to spot
where you want to take your water sample. Then fill it with water. This time we didn’t
analyze phosphorus concentration ourselves but we handed bottles for specialists in
laboratory.
6) Classify the species of animals
After using kick and catch method or other method you need to put the animals you
found into plastic jars filled with water and take them into the lab. Using microscopes
and some books/guides try to classify the specie of the animals.
8
RESULTS
During three days (22nd – 24th of June 2009) we were collecting samples from areas
mentioned in methods. Then after previous examination we estimate the water quality
according to ASPT – index (Average Score Per Taxon). We found 40 different families of
animals, which are good indicators of water conditions.
ASPT index in spots
8.0
7.5
7.0
ASPT value
6.0
5.0
4.8
4.7
4.25
4.0
4.6
4
3.6
3.0
2.5
2.0
1.0
0.0
Site 1
Stream
Site 1
Pool
Site 2
Stream
Site 2
Pool
Site 3
Stream
Site 3
Pool
Site 4
Pool
Site 5
Stream
Spot
Diagram 1. ASPT values in rivers
The ASPT – values are rather higher in riffles than in pools. In the first site (the river near the
crossroads located close to the city Rönnsbol) our calculations shows over 1 point difference
between riffle and pool (Diagram 1). We found similar situation in site 3 (in the middle of
river Broströmmen near Getingarne) where value for riffle is 4 and for pool only 2,5.
Opposite situation we noticed in site 2 (the river near the crossroads close to Roslags – Bro),
where difference between riffle and pool is over 3 points. This time it was pool where water
quality was higher. In the last two sites we could hardly find two different spots (riffle and
pool). So that in site four (the river Broströmmen flowing into the lake Gillfjärden) we have
no results for riffle, but for pool ASPT – value is 4,8. And in site number five (the river
connecting the lake Gillfjärden and Norrtäljeviken (place between Runsten and
Hårnackalund)) we have no results for pool, but for riffle ASPT value is 4,6 (look at diagram
1).
9
pH values in different spots
9.4
9.2
9.2
pH value
9
8.8
9
8.8
8.6
8.5
8.4
8.5
8.5
8.5
8.4
8.2
8
Site 1
Stream
Site 1 Pool
Site 2
Stream
Site 2 Pool
Site 3
Stream
Site 3 Pool Site 4 Pool
Site 5
Stream
Spot
Diagram 2. pH values in rivers
The pH values varied from 8,4 to 9,2. The highest values were measured in the fifth site
where the measurement was 9,2. The lowest value (8,4) was noticed in site two (pool). Most
common result for examined sites was 8,5 (look at diagram 2).
Temperature
25
Temperature
20
15
14.5
15
16.8
16.8
17.1
17.8
17.9
19.6
10
5
0
Site 1 Stream Site 1 Pool Site 2 Stream Site 2 Pool Site 3 Stream Site 3 Pool
Site 4 Pool Site 5 Stream
Spot
Diagram 3. Temperature in rivers
The weather during the days of our fieldwork weather was sunny and hot.
10
Compare of average stream speed
0.50
0.45
Stream speed, m/s
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.06
0.05
0.00
Streams
Pools
Type
Diagram 4. Stream speed in rivers
The speed in riffles was eight times faster than in pools. See diagram 4.
Total phosphorus in rivers
70
61
Total Phosphorus
60
56
50
45
40
39
39
34
30
20
23
24
10
0
Site 1
Stream
Site 1 Pool
Site 2
Stream
Site 2 Pool
Site 3
Stream
Site 3 Pool Site 4 Pool
Site 5
Stream
Spot
Diagram 5. Total phosphorus in rivers
The lowest value of total phosphorus was in site 1 (the river near the crossroads located close
to the city Rönnsbol) and it was 23-24. The highest results were noticed in site 4 (56) and site
2 (64).
11
DISCUSSION
There are a lot of factors that together have great influence of water quality in reservoirs such
as rivers and streams. On the basis of examination and monitoring we can conclude why
water quality is different. But you must remember that there might be a special case when
water quality isn’t different.
If the water flows from lake to the sea through rivers located in areas where people and
animals live and where infrastructure is developed, then the abiotic factors (temperature,
pH, oxygen condition and total phosphorus) in river water are higher than the water in the
Lake Erken.
As the beginning of our work we stated three hypotheses. The first one was about our
predictions based on information from different sources. In the first hypothesis we supposed
the results from rivers such as temperature, pH and total phosphorus to even be higher than in
lake due to the fact that rivers flow from the lake to the sea through areas where people and
animals live and where infrastructure is developed. The most common surrounding to
investigated rivers was car roads or highways; in addition in neighbourhood of a few of them
we found also beach, farm and household. By using method mentioned in materials and
methods section we examined parameter in each of selected area. Then after gathering the
results we compared it with the results introduced in the work ”Quality or not?”10 which
include the parameters about water in Lake Erken.
Compare of parameters between Lake Erken and streams
45
40.1
40
35
27.5
Value
30
25
20
Lake Erken
15.4
Streams
16.9
15
8.7
10
8.7
5
0
Temperature
pH
Total Phosphorus
Parameter
Diagram 6. Compare of abiotic factors between Lake Erken and average values from streams
As it is shown in diagram number 6 water was more or less alkaline. None of water streams
had acidic character. Values from streams and Lake Erken were over 8 but some of theme are
even higher than 9 (diagram 2). If we try to find reasons for that differences we will probably
need to concern the fact that in every river located near to road or highway the pH values
were at least a bit higher. Two of our sites (Site 1 and Site 2) had high pH value (9,0 and 9,2)
10
Gulbe K., Vellin E. Quality or not? 2009
12
due to their surroundings (field and road), but taking the average of streams and average for
Lake Erken, the level of pH is the same. And these results can be effects of the common
surrounding areas and same water system. They are also alarming because some values were
slightly over 6-9 values, which are the most beneficial values for animals living in water
reservoirs. 11
The next parameter we want to consider is temperature of water in streams and Lake Erken. It
is also shown in diagram number 6. The temperature values were increasing through the days
we were collecting samples in our fieldwork. It is important to mention that the weather
before our fieldwork was rather cold and rainy but during 22nd – 24th of June when we were
conducting our field work the weather got sunny and hot. So that it is believable reason why
temperature seems to rise from site 1 to site 5. The results from Lake Erken can be also
explained by weather conditions on 24th of June when the lake was examined.
If we compare total phosphorus results we can see that difference between Lake Erken and
average values from streams is significant. The reason of such difference most likely is the
surroundings of selected rivers. All of them were located in neighbourhoods of
roads/highways, farms and fields. Such surroundings are constant source of phosphorus,
which comes into water. Nutrients such as phosphorus are needed for living organisms to
survive, but when concentrating of the substance gets to high it makes worse living conditions
for animals and eventually causes their death. Besides the more phosphorus we have, the
more plants will grow, which can turn water reservoir from eutrophic to hypereutrophic. And
as the result the riverbed became more muddy and shallow.
As the surrounding areas have a big effect on water quality in streams, 12 the ASPT-index
will decrease at each site, travelling from the outlet of Lake Erken towards the Baltic Sea.
Compare of ASPT values between Lake Erken and streams
7
6
Value
5
5.9
4.8
4.7
4.6
4.1
4
3.3
3
2
1
0
Lake Erken
Site 1
Site 2
Site 3
Site 4
Spot
Diagram 7. Compare of ASPT value between Lake Erken and streams
11
12
Brönmark C., Hansson L.A. The Biology of lakes and ponds, Second edition, 2005
The Erken report. Limnologi MN1. 2007
13
Site 5
Our examination let us consider and falsify our second hypothesis stated that As the
surrounding areas have a big effect on water quality in streams, 13 the ASPT-index will
decrease at each site, travelling from the outlet of Lake Erken towards the Baltic Sea. Even if
some values in rivers were higher, you can see, that there is negative trend. As you can see in
diagram number 7, the average ASPT results from examined rivers are lover than the values
from Lake Erken, which those rivers flow in, but as you can see in diagram 7 in some sites
results are higher than in Lake Erken. There can be a lot of reasons why the results are the
way they are. It is possible that river can easier exchange its water and in that way became
cleaner and animals more friendly, or it is possible that lakes more intensively are used by
people, who are living in their surroundings (for example beach). What is proved by other
examination is that the quality of water in rivers might higher than in Lakes Erken, but it also
can be lower. And this time it’s lower.
Due to the fact that water in pools is almost still 14 the ASPT index and water quality will be
lower than it is in flowing water – riffles.
Compare of results between pools and riffles
45
39.3
40
41
35
Value
30
25
17
20
Riffles
16.9
Pools
15
10
5
8.8
4.4
8.6
4.6
0
ASPT
pH
Temperature
Total phosporus
Parameter
Diagram 8. Compare of results between riffles and pools (average)
If you compare the ASPT – values from pool to riffle of one river, you can see that there is
always difference between the values (Diagram 1). One of our hypothesis stated that the water
quality from riffles is expected to be higher than from a pool. We base our theory on the fact
that water in pools is not exchanged so often as it is in riffles, because the speed of water is
faster, what we proved (see diagram 4). Mostly the results show us correctness of the
statement but if it is not a rule for every water reservoir. If we looked to average ASPT value
for riffles and pool we could see that results for pools are even higher than in riffles (Diagram
8). On the basis of examinating nutrients (see diagram 5) and pH (see diagram 2) we conclude
that often exchanged water in reservoirs does not guarantee the high quality. To find out what
exactly has the greatest input on difference, this project should be continued and more factors
should be examined.
13
14
The Erken report. Limnologi MN1. 2007
http://en.wikipedia.org/wiki/Stream_pool
14
During our fieldwork there were several incidents that didn’t help us to do our work for
100%. In some sites there were a lot of mosquitoes, which were very annoying. Also in one
site we were one person short so it was really hard to do things that were supposed to do with
two people not one.
After our examinations we know a lot more about water quality in rivers and what causes
such results. But there are a lot of different factors having huge input on differences between
reservoirs and between differences between results during a year. One of the factors why
water quality is different is seasonal changes is that different influence to water changes. In
winter there is less nutrients input from farms because land is covered with snow and it is too
cold for plants to grow. In spring and autumn unlike in summer and winter, water is mixing so
oxygen and other matters can go to deeper parts of water reservoir.
The fact can be really important for different species of animals and plants. During a year
seasons it is also temperature which changes therefore it has also great influence on oxygen
condition and water quality overall. For instance during hot year seasons the water
temperature increases and because of that amount of dissolved oxygen decrease so some
species of animals may not survive.
Another factor that has very big influence to water quality is human actions. In farms farmers
use a lot of nutrients, which in most cases go straight to water. At first it seems to be
beneficial because the more nutrients the more plants, but this action can lead to situation
when whole reservoir will be covered by plants. That change of habitat can cause death of
many animals living in water reservoirs. An example of this you can see in site 3. Also
motorways have a big input. If they are located near the water reservoirs the quality of water
always decreases because of all kinds of petrol and oils.
15
CONCLUSION
If the water flows from lake to the sea through rivers located in areas where people and
animals live and where infrastructure is developed, then the abiotic factors (temperature, pH
and total phosphorus) in river water are higher than the water in the Lake Erken. We
examined selected areas and compared our results to those from Lake Erken. pH results were
simply the same for average result of rivers and Lake Erken - 8.7. Only two of rivers results
were not common – in site 2 (pH 9.0) and site 5 (pH 9.2). We can explain this fact by the
surroundings near the rivers. Temperature was increasing due to good weather condition
during our fieldwork. The average of phosphorus in rivers was almost 2 times higher than in
Lake Erken. The effect of this shows the ASPT values from examined reservoirs.
16
REFERENCES
1. The Erken report. Limnologi MN1. 2007
2. Armitage P.D., Moss D., Wright J.F., Furse M.T. 2005. The performance of a new
biological water quality score system based on macroinvertebrates over a wide range
of unpolluted running-water sites.1982
3. The biology of streams and rivers. In: Life in running water
4. Stream Pool. WWW document: http://en.wikipedia.org/wiki/Stream_pool. Date
visited 16 June 2009.
5. Stream. WWW document: http://en.wikipedia.org/wiki/Stream. Date visited 16 June
2009.
6. Penka A., Tamm M.H., Benthic animals as indicators: from Lake Erken to the Baltic
Sea, 2008.
7. Gulbe K., Vellin E. Quality or not? 2009.
8. Brönmark C., Hansson L.A. The Biology of lakes and ponds, Second edition, 2005
17