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ZOOPLANKTON ASSEMBLAGES IN SEMATAN RIVER, SEMATAN, SARAWAK Nurul Syaza Bt ZainGI
QL
123
N974
2011
Bachelor of Science with Honours
(Aquatic Resource Science and Management)
2011
,.. hsat Khld.t Maklamat Akademik
UNlVERSm MALAYSIA SARAWAK
Zooplankton Assemblages in Sematan River, Sematan, Sarawak
P,KHIDMAT MAKLUMAT AKADI!MIK
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1000235688
Nurul Syaza Bt Zainol
This project is submitted in partial fulfillment ofthe requirements for the degree of Bachelor of Sciences with Honours (Aquatic Resource Science and Management) .,
I,
Faculty of Resource Science and Technology
UNIVERSITI MALAYSIA SARAW AK
2011
,
Acknowledgement
Alhamdulillah. Thanks for God. I would like to express my thankfulness to my
supervisor, En. Mohd Nasarudin Harith for his supports and guidance through this year until
able to complete this study. I would love to thank: my parents, Zainol b. Yusoff and Habsah bt.
Hamid and other family members for their financial and emotional supports. Thank you to Mr.
Azlan, Mr. Nazri, Miss Nur Atiqah bt. Mohamad Yusoff and all FRST's staff that involved in
Sematan River water sampling and for their helps and advices. Last but not least, I would like
to express my gratitude to all Aquatic Science's lectures and class members for their advice,
support, love and care.
DECLARA TION I hereby declare that no portion of the work referred to in this dissertation has been submitted
in support of an application for another degree of qualifications of this or any other university
or institution of higher learning.
Nurul Syaza Zainol (22069)
Program of Aquatic Resource Science and Management
Department of Aquatic Science
Faculty of Resources Sciences and Technology
University Malaysia Sarawak
II
Pusat Khidmat Mlkiumat AkJdemik
UNIVERSm MALAVSIA SARAWAK
Table of Contents Acnowledgement ........................................................................ ..':
I
Declaration ............................ ............................................... .......
II Table of Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III List of Abbreviation.........................................................................
V
List of Tables .......................... ... ............ .. ............ ... ......................
VI List of Figure ................................................................................
VII List of Appendices .......... ... ............... ............... ..... ................. ... .....
VIII Abstract '" ........................... ...... ... ... ................................. ... .........
1
1.0 Introduction........................ ... .............................. ... ............ ......
2
2.0 Literature Review.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
2.1
Distribution of zooplankton ..... ... ............................ ... ..... .
5
2.2
Freshwater zooplankton ............ .................. ............... ... .. .
6
2.3
Classification of Zooplankton ............................ ................
9
2.4
Importance of Zooplankton ...... .... .......... .. .............. .... .. ... .
11 2.5
Relation between zooplankton and physico-chemical characteristic
12 2.6
Behaviors of Zooplankton ............................................... .
14 3.0 Material and Method...................... ........... ............ ... ... ... ............
15 3.1
Sampling Site .......................................................... . ... ..
15 3.2
Field work ............................................ ... .................. .
17 3.3
Laboratory work and analysis .......................................... .
18 3.3.1
18 Zooplankton analysis .....: ....................................
,
3.3 .2 Water quality analysis ............................ .. ........ ..
20 3.4
Data analysis............ ......................... .. ............. ... ......
24 3.4.1
Species diversity of zooplankton composition....................
24 3.4.2
Similarity analysis of zooplankton composition..... ......... ...
24 3.4.3
Statistical analysis........................................................
25 III _.
I
4.0 Result and Discussion ................................... .. ........................ .. .
26 Zooplankton assemblages ............... .......... .. ........... . .... ... . ;
26 4.1.1 Zooplankton genera occurrence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26 4.1.2 Zooplankton genera composition and abundances .........
29 4.1 4.1.3 Comparison of individual zooplankton composition in different season .......................................... .. ......
34 4.1.4 Zooplankton Diversity........................ ... ......... ... ....
39 4.1.5 Zooplankton Similarities...... .. .......... ... ... ...... ...... ...
41 Water Quality Parameters .......... ............................. .. ...... .
43 4.2.1 Selected physico-chemicals parameters............... ... ....
43 4.3 Relationship of Environmental parameter to zooplankton assemblages
55 4.4 Correlation analysis between zooplankton diversity and 4.2 environmental parameter ...............................................
.
59 5.0
Conclusion ........................................................................ .
62 6.0
References ..... . ........................ . ......................................... .
64 7.0
Appendices .......................................................................... .
69 IV
....
List of Abbreviations
I
TEMP
Temperature
DO
Dissolved oxygen
BOD
Biochemical oxygen demand
pH
Potential of Hydrogen TSS
Total suspended solids N03-N
Nitrate nitrogen NH4- N
Ammonia- nitrogen pol
Orthophosphate
NTU
Nephelometric Turbidity Units
°C
Degree Celsius
mglL
milligram per Liter
L
Liter -
,
Ii
v
I
I
I
List of Tables
Table
Page
Description
1
Classification of zooplankton based on sizes
2
Classification of zooplankton
planktonic life
3
Brief description of sampling stations
18
4
Nutrient water analysis (Hach DR 2010)
21
5
Zooplankton genera occurrence in all stations
28
6
Distribution of zooplankton composition at all
stations
33
7
Different zooplankton composition of dry and wet
season
34
8
Zooplankton diversity
39
9
Sorensen's index (%)of zooplankton genera found in
all stations
41
10
Correlation analysis (r) between zooplankton
diversity and water quality variable
61
VI
1
based
on
9
their
10
,.....
List of Figures
Figure
I'
Description
Page
1 (a)
Malaysia
16
1 (b) Sematan area
16
1 (c) 6 Sampling site in Sematan River involved during
this study
Percentage (%) of zooplankton groups in Sematan
River
Comparison of individual zooplankton composition
in dry and wet season
Temperature value recorded at six sampling stations
in Sematan River
pH value recorded at six sampling stations in
Sematan River
16
2
3
4
5
Dissolve oxygen value recorded at six sampling
stations in Sematan River
Biological Oxygen Demand (BODs) value recorded
at six sampling stations in Sematan River
6
7
29
34
43
44
45
46
Salinity value recorded at six sampling stations in
Sematan River
Turbidity value recorded at six sampling stations in
Sematan River
47
10
ORP value recorded at six sampling stations in
Sematan River
49
11
Clorophyl a (mg/m3) value recorded at six sampling
stations in Sematan River
50
12
A'm monia-nitrogen (mg/L) value r~corded at six
sampling stations in Sematan River
51
13
Nitrate-nitrogen (mg/L) va)ue recorded at six
sampling stations in Sematan River
52
14
Nitrite-nitrogen (mg/L) value recorded at six
sampling stations in Sematan River
53
15
Nitrite-nitrogen (mg/L) value recorded at six
sampling stations in Sematan River
54
8
9
VII
I
48
I
:
List of Appendices
Appendices
Description
Page
A
Abundance ofthe common zooplankton genera in
Sematan River 69 B
Dominant genera and amount of zooplankton
70 C
Water Quality Parameters
71 VIII Zooplankton Assemblages in Sematan River, Sematan, Sarawak
Nurul Syaza Bt Zainol
Program of Aquatic Resource Science and Management Faculty of Resources Sciences and Technology University Malaysia Sarawak ABSTRACT
A study on the zooplankton assemblages in Sematan River, Sematan, Sarawak was carried out to evaluate the
species composition, species diversity, species similarity, abundance, distribution and selected water physico­
chemical parameters. Zooplankton and water samples were collected from six sampling stations at 7-8 August
2010 for dry season and 15-16 January 2011 for wet season. Zooplankton and water samples be analyzed using
standard methods in interpreting infonnation about zooplankton assemblages and its relationship to
environmental parameters. A total 900 zooplankton belonging to seven groups, four taxa and 14 genera were
identified. Copepoda dominated the zooplankton population which made up of 68.44 % of total abundance.
Zooplankton abundance followed the order: Copepoda > Cladocera > Mollusca > Protozoa > Ostracoda >
Anostraca> Rotifera. A dominant genus identified in this study was Limnocalanus which represented 29.56% of
total amount. The seasonal pattern was observed which recorded zooplankton composition was much higher
during dry season (866 individuals) compared to wet season with lowest present (31 individuals). Species
diversity values vary from 0.562 to 2.042 and recorded mostly in high value for each station during dry season.
The Sorensen's index value falls were much larger in range between 13.33 % to 76.19 % among all stations.
Water temperature of different season, turbidity, dissolve oxygen, pH and nutrients were main environmental
parameters which were found to influence zooplankton composition in Sematan River.
Key words: Zooplankton assemblages, environmental parameters, dry and wet seasons, Sematan River
ABSTRAK
Kajian ke atas kehadiran zooplankton di Sungai Sematan telah dijalankan untuk merekodkan komposisi spesis,
kepelhagaian spesis, persa"lPan, spesies kelimpahan dan parameter telpilih di permukaan air. Zooplankton dan
sampel air diambit dari enam stesen pada 7-8 Ogos 2010 untuk 'rusim panas dan 15-16 Januari 2011 untuk
musim hujan. Zooplankton dan sampel air dianalisis menggunakan kaedah piawai untuk menghasilkan maklumat
berkaitan kehadiran zooplankton dan hUbungannya dengan parameter persekitaran. Sejumlah 900 zooplankton
dari tujuh kumpulan, empat taxa dan 14 genera telah dikenakpasti. Copepoda menidominasi populasi
zooplankton iaitu 64.88% dan jumlah kelimpahan. Jumlah zooplankton mengikut urutan: Copepoda >
Cladocera > Mollusca > Protozoa > Ostracoda > Anostraca > Rotijera. Genus yang dominan adalah
Limnocalanus iaitu 29.56% dari jumlah keseluruhan. Kelimpahan berdasarkan musim, komposisi zooplankton
adalah lebih tinggi semasa musim panas (866 individu) berbanding dengan musim hujan (31 individu). Nitai
kepelbagaian sepsis yang direkodkan adalah dari 0.562 kepada 2.042 dan merekodkan nitai yang tinggi untuk
setiap stesen semasa musim panas. Suhu air berdasarkan perbezaan musim, kekeruhan, kandungan oksigen, pH
dan nutrien adalah parameter persekitaran yang utama dalam mempengaruhi komposisi zooplankton di Sungai
Sematan.
KflkI kunci: Kehadiran zooplankton, parameter persekitaran, musim panas dan musim hujan, Sungai Sematan
1
1.0
INTRODUCTION Zooplankton are essentially non-motile organisms but drift with water current and
therefore they are susceptible to pollutants in the water (Uttah et al., 2008). The
physico-chemical parameters and nutrient status of water body play an important role
in governing the production of zooplankton which is the natural food of many species
of fishes (Basu et aI., 20 I 0). Dominance of zooplankton community and their
seasonality are highly variable in different water bodies according to their nutrient
status, age, morphometry and other locational factors of the water (Rajashekhar et al.,
2009) .
Zooplankton can be divided into few different groups such as crustacean, rotifers,
coelenterates, ctenophores, annelids and mollusk (Pary,1992). Zooplankton more
specifically three taxonomic groups; Phylum Rotifera; Subclass Copepoda; and
Suborder Cladocera, are an integral component of freshwater ecosystems (O'Brien,
2007). In general, freshwater zooplankton are dominated by four major group such as
protozoa, rotifer, and two subclasses of crustacean, the cladocerans and copepods.
Crustaceans are the most abundant and the main group of zooplankton species,
..
especially those in the orders of
cyclopoid copepod are often
Calanoid~,
dominat~d
Cyclopoida and Cladocera, and the
in the assemblage (Schiel, ND). Cladocerans
are usually most abundant in freshwater ecosystem and the common genera are
Daphnia and Bosmina (Edmondson, 1982).
2
Zooplankton are important contributors in the food webs of open-water ecosystems for
both marine and freshwaters. They act as important link in the transfer of energy from
the primary producers to the consumers. Community structure, biomass, and
production are influenced by both producers and consumers which function
simultaneously (Mayer et
at., 1997). Its intermediate position between phytoplankton
and fish, the zooplankton can responds to changes in both food and predation (Baloch
et at., 2010).
Water quality; the physico-chemical and biological characteristics of water, plays an
important role in plankton productivity (Yeamin et at., 2007). Biological monitoring is
the use of living organisms of zooplankton in purpose to determine the presence,
amounts, changes in and effects of physical, chemical, and biotic factors in the
environment (Uttah et
at., 2008; Baker, 1976). The important aspect in water
biological monitoring is species diversity. Species diversity can determine the health
status of an environment (Uttah et at., 2008; Ogbeibu and Edutie, 2002). The types and
numbers of invertebrates living in the river can determined the health of the river
(Uttah et
at., 2008). Different types of invertebrate species will have different
tolerances rate to pollution and they are also influenced by the quality of their habitat.
Zooplankton play role as indicators of conditio"n of their habitats as they can respond
quickly to their aquatic environmental changes (Basu et at., 2010; Thorpe and Covich,
1991 and Carriack and Schelske, 1997). The factors that influenced the growth and
distribution of zooplankton are some of abiotic factors such as pH, alkalinity,
temperature, carbon dioxide and nutrients which are responsible for the organic
production (Yeamin et aI., 2007; Pulle and Khan, 2003). The biotic factors such as
3
food limitation, predation and competition also influence the zooplankton distribution
(Ferdous and Muktadir, 2009; Beyst et
at., 2001; Christou, 1998):'" According to
Pandey (2004), a study that was conducted in river Ramjan of Bihar, India revealed
that abiotic parameters such as pH, transparency, temperature, dissolved oxygen and
some micronutrients are related to zooplankton abundance.
The previous zooplankton studies in Sarawak have been carried out in Kuching Bay by
Volin (2005), Batang Lupar by Arbe (2007) and Punang, Lawas & Limbang River by
Nuratiqah (2009). However, there is still inadequate data especially the assemblages of
zooplankton in Sematan River. Thus, study of zooplankton assemblages at Sematan
River need to be carried out in order to find the relationship between zooplankton
assemblages and their abundance to the water quality parameters. The objectives of the
study are to (1) identify and quantify zooplankton community in Sematan River; (2)
discuss the variations in selected water quality parameters; (3) find the relationship
between zooplankton distributions with water quality parameters.
4
I
Pusat Khidmat Maldumat Akadem.lk VNlVERSm MALAYSIA SARAWAK 2.0
LITERATURE REVIEW
2.1
Distribution of Zooplankton
Zooplankton are microorganism that float freely in surface water column of water
bodies (Shanna, 2008). They are attract to sunlight and nutrient that available and be
adapted to suspension in the sea and freshwater (Battish, 1992). They move in the
sunlight zone where food resources are most abundant and they also found in deep
ocean water (Ferdous and Muktadir, 2009). Zooplankton distribution primarily
determined by water waves and current (Sharma, 2008). They are very weak swimmers
and they drift in water column of ocean, seas and fresh water bodies (Ferdous and
Muktadir, 2009).
Their abundance and species comp<!sition of zooplankton community are also
controlled and influenced by their susceptibility to environmental stressors of physical,
chemical and biological factors of the water ecosystem. Water parameters such as
temperature, salinity, pH and electrical conductivity can influence the composition and
population density of zooplankton (Sampaio et
at., 2002). The composition of
zooplankton also can be influenced by the distribution of phytoplankton and its species
composition (K~jalainen et at., 1996).
5
,......
2.2
Freshwater Zooplankton
!I
The freshwater zooplankton are commonly smaller in size and only represented by
fewer animal compare to marine counterparts (Davies and Otene, 2009). The
freshwater zooplankton comprised of Protozoa, Rotifera, Crustacea, Cladocera,
Copepoda, Ostracoda and Meroplankton organism including insect larvae (Davies and
Otene, 2009; Parsons, 1980).
2.2.1
Protozoa
Planktonic protozoans are classified as unicellular ciliated or flagellated organisms.
Ciliates organism are many species in all size classes from <20 11m to about 2 mm.
They graze bacteria, unicellular algae, filamentous cyanobacteria, other protozoa and
occasionally rotifers and micro zooplankton. Flagellated organism uses the flagella for
locomotion, feeding, or both. Flagellates are the principal consumers of suspended
bacteria, and important grazers of the bacteria in surfaces and sediments (Finlay,
1998). Protozoa are feed on either picoplankton or nanoflagellates and small
nanophytoplanktons according to their size (Ferdous and Muktadir, 2009). The relative
size of the
~,rotozoan
to its prey also influences their most efficient food-capturing
mechanism. Where the predator to prey length ratio exceeds 10: 1, filter-feeding
prevails. Where the ratio is smaller than 10: 1, raptorial feeding (seeking out and
capturing relatively large, individual food particles) is more common (Finlay, 1998;
Fenchel, 1986).
6
2.2.2
Rotifer
"
Rotifers can be classified as soft-bodied metazoans of invertebrates and they are
having a very short life cycle among other type of plankton. There are only about 100
rotifer species that widely spread are planktonic organism and rotifer life cycles are
influenced by temperature, food and photoperiod (Ferdous and Muktadir, 2009;
Dhanapathi, 2000). Rotifers are considered to be the most diverse group of
zooplankton (Baloch, 2010). Rotifer may increase into large number in rapidly under
favorable environmental conditions of that area (Dhanapathi, 2000).
2.2.3
Cladoceran
Cladocerans are an important group among zooplankton. They form the most valuable
and nutritive group of crustaceans' for fishes in the food chain in water column
(Ferdous and Muktadir, 2009). Cladocerans are mostly herbivorous in their feeding
habit (Baloch, 2010) that feed on smaller zooplankton, bacterioplankton and algae
(Ferdous and Muktadir, 2009; Murugan et at., 1998). They are able to response against
pollutants which can react in the low concentration of contaminants in water column.
2.2.4
Copepod
,
\
Copepods zooplankton have toughest or hardest exoskeleton which can help them to
swim faster compare to any other zooplankton (Ferdous and Muktadir, 2009). Their
feeding habits are differing between the three orders of zooplankton copepods.
Generally, Cyclopoid copepods are carnivorous that live on other zooplankton and fish
7
larvae. They also feed on algae, bacteria and detritus. The calanoid copepods are
commonly omnivorous that feed on such as ciliates, rotifers, algae, bacteria and
detritus. Their food intake of calanoid copepods is mostly dependent on their age, sex,
season and food availability. The other group is harpacticoid copepods that are mostly
benthic (Ferdous and Muktad ir, 2009).
Copepod also can tolerate in harsher
environmental forms due to their physical structures and versatile feeding habits
(Ferdous and Muktadir, 2009).
2.2.5
Ostracod
Ostracods generally are bottom dwellers of water column (Ferdous and Muktadir,
2009). They mostly live on detritus and dead phytoplankton. These organisms are act
as food for fish and benthic macroipvertebrates in waterbodies (Chakrapani et al.,
1969; Ferdous and Muktadir, 2009).
8
I
,---­
r
I
2.3 Classification of Zooplankton
The classifications of zooplankton are based on their size and duration of their
planktonic life. In this aspect, zooplankton can be divided into picoplankton,
nanoplankton, microplankton, mesozoplankton, macroplankton and megaplankton
(Table 1). Classification of zooplankton based on their stage of development can be
divided into two categories; meroplankton and holoplankton.
Table 1: Classification of zooplankton based on sizes
(Adapted from: Callieri, 2002 as cited in Dussart, 1965)
Class
Example
Size
Nanoplankton
Flagellates
2-20 /lm
Microzooplankton
Protozoan, rotifer
20-200/lm
Macrozoop lankton
Amphipod, shrimp, fish larvae
200-2000/lm
Megaplankton
Copepod
>2000/lm
1
Microzooplankton are a diverse group of organisms that are found in all aquatic
.
habitats. The arthropods which include in the abundant and diverse of copepod are
66% of the total meso zooplankton species (Diebel, 1992). The change in the
abundance or species composition of meso zooplankton may reflect fundamental
change in the ocean environment that affecting phytoplankton (Clark, 1992). This is
because meso zooplankton are the primary consumers of phytoplankton and plays
important function in energy economy of the sea that forming a vital connection
9
,...
between the phytoplankton at the base of the food web to the higher consumer level of
finfis h, shellfish, bird and mammals (Diebel, 1992).
Zooplankton can be divided into duration of their planktonic life or their development
stage as summarized in Table 2, which are Holoplankton and Meroplankton (Michael,
1990). Holoplankton will remain as plankton for their entire life, while meroplankton
will a ct as planktonic organism only in larval stages of their life cycle (Harnzah, 2007).
Table 2: Classification of zooplankton based on their planktonic life
(Adapted from Michael, 1990)
Class
Example
Description
Holoplankton
Copepod,
d ino flagellated,krill,
amphipods
Remain plankton for their entire life cycle
Meroplankton
Fish larvae, sea
urchins, seastars,
crustaceans, worm,
gastropods
Act as planktonic organism only a portion
of their life cycle
.
II
10
1
2.4
Importance of Zooplankton
Zooplanktons contribute significantly to biological productivity of freshwater
ecosystems (Naz, 2008). The availability of zooplankton is an important factor that
determines the relative survival of juvenile fishes (Fernando, 1994). Young fishes
mostly breed in area where the planktonic organisms are plenty to get sufficient food
for their survival and growth, especially in pelagic area. Therefore, the occurrences and
distribution of zooplankton can influence the pelagic fishery potentials fishes.
Zooplankton plays significant role in aquatic ecosystems (Baloch et at., 2010) due to
central position between the autotrophs (algae, phytoplankton) and other heterotrophs
(fish and other carnivores). They form an important link in the food web of aquatic
ecosystems (Tevlin and Burgis, 1979; Gulati, 1982). In addition, they are primary
consumer of second trophic level in aquatic food web in most aquatic environments
(Basu et aI., 2010; Licandro and Ibaney, 2000). Zooplankton forms the principal source
of food for omnivorous and carnivorous fishes (Hossain et at., 2007; Prasad and Singh,
2003), and also support the necessary amount of protein for the rapid growth of larval
carps (Basu et at., 2010; Hussain and Rahman, 2008). Zooplankton function to provide
fish with nutrients seeing as fish requires proteins, fats, carbohydrates, mineral salts
and water in the right quantity (Davies and Otene, 2009; Guy, 1992). Fish can modify
zooplankton biomass and thus also phytoplankton concentration due to changes in the
intensity of zooplankton grazing (Gulati, 1982).
11
Zooplanktons act as an important group as most of them feed upon and incorporate the
primary producers into their bodies and then make themselves available to next higher
organisms in the food chain (Michael, 1968). They contribute significantly to
biological productivity of freshwater ecosystem and playa major role in the energy
transfer at secondary level (Naz, 2008). They are very important in the energy
economy of the sea, that forming a vital connection between the phytoplankton at the
base of the food web to the "higher" consumer level including finfish, shellfish, bird
and mammals (Deibel, 1992). Community structure, biomass, and production are
influenced by both producers and consumers which function simultaneously (Mayer et
ai., 1997). The abundance of producer and consumer's composition will influenced to
the level of community structure of zooplankton in water ecosystem.
2.5
Relationship between zooplankton and physico-chemical characteristic
Zooplankton are highly sensitive to environmental variation and provide important
indication of environmental change or disturbance as a result of their abundance,
species diversity or community composition (Sharma et ai., 2008). The diversity of
species, amount of biomass and abundance of zooplankton community can be used to
determine health of ecosystem (Uttah et ai., 2008; Ogbeibu and Edutie, 2002).
Zooplankton indicates the quality of the' water body in which they are found and as
excellent indicator of the environmental condition by respond to low dissolve oxygen,
high nutrient levels, toxic contaminant, poor or abundance food quality and predation
(Johnson, 2000),
12
The community interactions in pelagic food webs are affected by small to large scale
of physical, chemical and biological processes that are tropicaHy dynamic. The
interactions are also governed by nutrient limitation, competition, predation and other
ecological forces (Mayer et at., 1997). Water parameter such as temperature may give
different affect to the zooplankton that depends on their metabolic rate with their
respond to their temperature. Organisms like zooplankton tend to adjust temperature
slowly because their metabolic rate cannot respond in drastic temperature change
(Makinster et at., 2004). Some zooplankton can survive in colder weather in winter
month and some can thrive in wanner temperature. Therefore, different plankton group
will flourish under different temperature.
Besides that, pH is important to act as indicator of the water quality in the water bodies
(Jonna[agadda and Mhere, 2000). Water ecosystem that have pH range 6-9 can be
threatened by increasing rate of acidic precipitation and the change in acidic levels will
give risk ofa zooplankton and phytoplankton declination (Makinster et at., 2004).
Suspended solid also will give influence to the water quality parameters. Too high or
too low concentration of total suspended solid in water may limit the growth and may
cause death of many aquatic organisms (Ntengwe, 2006). Turbidity in water column is
caused by the occurrences of suspended of sa lid such as organic and inorganic matter,
plankton, silt and clay in the water hodies (Ntengwe, 2006). Turbidity may cause the
major effects in blockage of light and smother of organism (Y ong, 1999). Some
zooplankton will suffer and risk to declination of their composition due to clogged of
their feeding mechanism by suspended solid in the water.
13 Dissolved oxygen also influenced the zooplankton composition. Water is considered as
"healthy" when dissolved oxygen is above SmglL (iLau, 2003). The low level of
dissolve oxygen «2mg/L) would indicate poor water quality and will give the negative
effect on the aquatic life organism.
2.6
Behaviors of Zooplankton
Zooplankton conununity show vertical migration
In
the water column.
They
swimming actively both through up and back down again within 24 hours. The pattern
of normal diel vertical migration (NDVM) occurs in nocturnal and diurnal. Nocturnal
occur when zooplankton goes upward at night and diurnal occur downward during the
day. While the reverse diel vertical migration (RDVM) also occurs but it pattern does
not conunon. The pattern of migration occur when zooplankton go ascent through the
water column during the day and descent during the night. The function for the both
migration are to avoid predators by fish and reduce the risk of mortality (Lampert,
1989 in Hays et aI., 1996).
Zooplankton are more varied by patchiness, diurnal vertical migration and season.
Through vertical migration of both type and their presence at varying depths, the
zooplankton utilized to assess energy transfer at secondary level (Johanna, 1992).
Zooplankton feed on phytoplankton and transfers of plant materials into animal tissue
and be the basic food for higher animals.
14