This document describes a study on the vertical zonation and composition of meiofauna in Rearing Pond 2 of the Zamboanga State College of Marine Sciences and Technology. Meiofauna samples were collected from four stations at depths of 0-2cm, 2-4cm, 4-6cm, and 6-8cm below the sediment surface using a corer sampler. The samples were fixed with 5% formalin and sieved through 1mm and 250 micron meshes to extract the meiofauna. The goal of the study was to determine the meiofaunal composition and vertical distribution in the pond.

1. VERTICAL ZONATION
AND COMPOSITION
OF
MEIOFAUNA RP2 OF THE
ZSCMST POND

2. CHAPTER 1
INTRODUCTION
I. Background of the study:
Meiofauna are the tiny invertebrates living within the
sediment of the sea. The term meiofauna is derived from the
Greek word “meio” meaning smaller{Funch, 2002}.The size of
meiofauna ranges between 50 and 500 microns as compared to
the size of macro or large fauna.
Meiofauna can be found in a wide diversity of habitats.
They can occur in both freshwater and marine habitats, from
high on the beach to the deep sea. Meiofauna is found in
sediments of all kinds from the softest of muds to the coarsest
gravels, and all those sediments in between. Meiofauna also can
occupy several above sediment habitats like rooted vegetation,
moss, macoalgae fronds, seaice and various animal structures
{coral crevices, worm tubes, echinoderm spines} {Funch 2002}

3. Benthic meiofauna are important components of coastal
and estuarine ecosystems. As grazers of microalgae and
bacteria. Meiofauna have been shown to influence primary
production, nutrient cycling and other benthic metabolic
processes{Carman et al :1996, 1997, 2000, Manini et al,
2000Pinckney et al:2003}.
Organic matter {and nutrients} grazed by
meiofauna are assimilated or egested. When an animal dies,
remineralized nutrients become available for microbial
processes and primary production {Coull,1999}.
Because of the short generation time of meiofauna {weeks
to months},these processes may result in a relatively rapid
cycling of nutrients through the meiobenthos.
Utilization of microalgae, microbes and detritus by benthic
meiofauna facilitates energy and nutrient transfer to higher
trophic levels in benthic food webs {Coull, et al:}

4. II. Objective:
-To determine the meiofaunal composition of RP 2 of
ZSCMST POND
-To determine the vertical zonation of meiofauna in RP
2 of ZSCMST POND
III. Significance of the study:
-The study is deemed significant as it will provide
insight on the meiofaunal contribution to the general food
web in the pond.
IV. Scope and limitation:
-The study is limited to the vertical zonation and
identification of the meiofauna in Rearing Pond 2.

5. CHAPTER 2
REVIEW OF RELATED LITERATURE
Several studies reported that nematoda is the most dominant
taxa in the sediments {Rao,1987, Lee et al, 2003:Higgins and Thiel,
1988 and http://www.uft.uni-
bremen.deoekilogieMeiofaunaReport.pdf,2006}.
The class Nematoda consists of two subclasses, the Secernentea
and the Adenophorea. The main diagnostic characters are the
presence of caudal glands{secreting a sticky fluid},bristles, and
conspicuous amphids in the majority of Adenophorea, being either
absent or insconspicuous in the Secernentea. {Franz Riemann,1989}
Nematodes are usually bound to a substrate. They can be
brought into suspension by water column together with seston
particles. Every type of sediment is colonized by nematodes, from
almost dry dune sand to beach sand, coarse shell sublittoral grounds
to hadal trenches. Many nematodes do not need a rich oxygen supply
and may be regarded as facultative anaerobes. {Franz Riemann,
1979}.

6. Foraminifera
-These are classified as an order within the class Granuloreticulosea
because they posses delicate, filiform, granular pseudopodia which
branch and anastomose. All foraminifera are testate, although some
primitive forms may be able to leave their granuloreticulate and
pseudopodia.{Marszaleck, Wright, and Hay, 1969}.
Ostracoda
-are small crustaceans ranging in length from 0.08 to 32mm. Their
entire body is encased in a bivalved, calcified carapace which can be
smooth to variously ornamented. The two valves are joined by a
dorsal hinge opposed by closing muscle. The body is unsegmented
and has a reduced number of limbs. The head is larger than boyh the
thorax and abdomen combined. Ostracods are found in nearly all
aquatic environments {Dietmar Keyser}.

7. Polychaeta
Polychaetes are generally abundant in all soft substrata, except for
the coarsest sands. They are segmented worms, with each body segment
bearing paired, biramous{twobranched}appendages, termed parapods,
which may be variously modified according to the worms mode of
living. The two lobes of each parapod typically bear bundles or rows of
bristles, or chaetae, which may be important in identification{Higgins
and Thiel 1988}.
Oligochaeta
Microdile oligochaetes are generaaly slender and flexible, and they
often exhibit jerking movements. Several species are reddish, brownish
or orange due to the coloration of the blood or the chloragogen tissue
covering the gut. Some species are colorless and transparent, others
conspicuously white. {Gierre and Pfannkuche 1982}. The estuarine and
marine environments harbor a diverse fauna of small oligochaetes.
Virtually any kind of marine sediment contains at least one oligochaete
species, although not always in very high densities.{Christer Erseus}.

8. Turbellaria
Turbellarians are acoelomate bilateria without a definitive anus. They are
largely free-living with a cellular, usually viliated, epidermis. The worms are
often dorsoventrally flattened with anterior sensory and glandular regions.
Turbellarians are ubiquitous forms in freshwater and marine habitats and very
many associate with other organisms to various degrees {some are parasitic}.
The main factors which control the life and distribution of turbellarians in
eulittoral and sublittoral zones {marine, brackish, limnic} are temperature,
salinity, organic content, and grain size. These factors either operate directly or
influence such factors as pore size and drainage. Also important are water
content and the availability of oxygen and food. {Lester R. G. Cannon and Anno
Faubel}.
Gastrotricha
Members of this phylum are small, strap or tenpin-shaped, acoelomate
worms. Most adults are less than 1mm in length, some species are less than 100
microns, and others exceed 3mm. The bodymis flattened ventrally and arched
dorsally. It is divided into two regions, the head and trunk, which are often
externally indistinct. The head bears the mouth, a tubular nematode-like
pharynx, and the brain. All gastrotrichs have ventral locomotory cilia, and with
them, glide smoothly over the substratum.

9. Gastropoda
Gastropods sometimes lack a shell, gill and cephalic
disc, but are provided with one or two pairs of free head
appendages {tentacles, rhinophores,}axial hump, and
subepidermal spicule formations.
Insecta
Members of the class Insecta may be distinguished
from all other arthropods by the presence of 3 principal
body regions: head, thorax and abdomen, coupled with the
presence of 3 pairs of thoracic legs at some stage during
the life history of the animal. However, these ground-plan
characters are often not displayed by the immature stages
of some orders.

10. CHAPTER III
METHODOLOGY
I. Location and Duration of the Study:
-The study was conducted in the Rearing Pond 2 of Zamboanga State College
of Marine Sciences and Technology {ZSCMST} for a period of 90 days.
II. Materials and Methods:
Materials for collecting/sieving/fixing the quantitative samples:
-12 corer sampler with a length of 10cm and an inner diameter of 5cm, 48
plastic containers, sieves{250 microns and 1mm}, graduated cylinder
{1000ml}, Petri dish, wash bottle, 5% Rose Bengal solution, 144 liters of
filtered seawater, camera.
Materials for analysis of the quantitative samples:
-photomicrograph, stereo and compound microscope, photos of meiofauna
{By:Higgins and Thiel}.

11. III. Sampling:
The time of the day when the samples were collected was
about 7:00 o’clock in the morning in January 2011. There were
four{4} stations included and replication of samples was also
implemented. A core sampler{modified from http://www.in-
tres.com/articles/meps/133m/133p155.pdf,2007 }.was used in
collecting sediment amples that are subject for meiofaunal
extraction. The inner diameter of the core is 5cm and the length
is 10cm. The sediment samples were collected by pushing the
core sampler on the substrate. Upon its withdrawal,the opening
was covered by the palm of one hand to avoid the sediments
from spilling out, and each core was cut in 4 slices from
particular layers;{0-2cm, 2-4cm,4-6cm,6-8cm}.[modified from
http://www.esf.edu/schulz/Marine Ecology/Meiofauna.html.].
The sediment slice{subsample} were transferred immediately
into a plastic container. The identification of the samples
includes two letters and one no., the first leter refers to the
station; the second refers to the no. of replicate; and the no.
indicates the layer; 2 for the first layer{0-2cm}, 4 for the second
{2-4cm}’ 6 for the third{ 4-6cm}and 8 for the fourth layer{6-
8cm}.

12. IV. Fixing and Sieving:
A 5% formalin solution was used to fix the specimen in the
sediment prior to extraction{adjusted concentration from 10%
in http://www.en-wikipedia.org/wiki/Meiobenthos,2007 }.
Sieving of specimens {meiofauna} were done in Aquatic
Biology Laboratory. A simple decantation technique [adopted
from http://www.en-wikipedia.org/wiki/Meiobenthos2007 ] was
conducted using a 1000ml of graduated cylinder. This was done
by pouring each of the sediments samples inside the cylinder,
the other hand held the bottom. The cylinder was inverted
slowly for several times and the sediment was allowed to settle
for 1 min. The supernatant was filtered through 1mm and 250
microns sieves. The collected specimens{meiofauna} were
removed from the sieve using wash bottle and collected in Petri
dish. A 1% Rose Bengal solution adopted from the methods of
Higginss and Thiel {Introduction to Meiofauna} was used in
staining the specimens to facilitate counting and identification.

13. V. Meiofaunal Analysis:
The collected meiofauna were brought in the
Hatchery and Wet Laboratory for documentation of
the different specimens and it was done using
photomicrograph. The organisms were classified in
the main taxonomic group. Counting was done using
compound microscope with the aid of a counting
dish. Tallying of specimens was done upon counting.
THE density unit used is the number of individuals
per 31.416 cu. cm. of the volume of the sediment
{subsample}. The morphological features of the
specimen were referred to the photos of Meiofauna
given by:{Introduction to Meiofauna by: Higgins
and Thiel}.

14. Figure 1.
Figure 1.FIELD SAMPLING MEIEOFAUNA
. REPRESENTATIVES

15. Figure 2. Meiofaunal Representatives including fish
larvae;(A & B) Nematoda spp.
(C) Foraminifera spp. (D)Ostracoda spp. (E) Turbellaria spp.
(F) Polychaeta spp. (G) Oligochaeta spp. (H) Gastrotricha
spp. (I) Insecta spp. (J) Gastropoda spp. (K). Fish Larvae

17. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 1
Taxonomic
Composition
S1 S2 S3 S4 Total %
Distribution
Nemotoda
9 10 99 78 196 34.32.%
Poly -chaeta 0 0 0 0 0 0%
Oligochaeta 1 1 1 4 7 50%
Foraminifera
10 14 2 62 88 50.57%

18. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 1
Taxonomic
Composition S1 S2 S3 S4 Total %
Distribution
Ostracoda 11 11 6 1 11 17.57%
Gastropada 0 1 0 6 7 35%
Turbellaria 7 2 0 1 10 58.82%
Gastrotrciha 2 0 0 0 2 28.578%
Insect 0 0 0 0 0 0%

19. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 2
Taxonomic
Composition S1 S2 S3 S4 Total %
Distribution
Nemotoda 7 7 51 44 109 19%
Poly -chaeta 0 0 0 1 1 33.33%
1 0 0 1 2 14.28%
Oligochaeta
Foraminifera
11 6 1 20 38 21.8%

20. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 2
Taxonomic
Composition S1 S2 S3 S4 Total %
Distribution
Ostracoda 8 3 1 9 21 12.731%
Gastropada 0 0 0 5 5 25%
Turbellaria 2 1 0 0 3 17.6%
Gastrotrciha 0 0 0 0 0 0%
Insect 0 0 0 0 0 0%

21. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 3
Taxonomic
Composition
S1 S2 S3 S4 Total %
Distribution
Nemotoda 7 4 23 48 82 14.4%
Poly -chaeta 1 0 0 0 1 33.33%
Oligochaeta 0 0 0 2 2 14.28%
Foraminifera
8 4 1 14 27 15.52%

22. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 3
Taxonomic
Composition S1 S2 S3 S4 Total %
Distribution
Ostracoda 11 3 1 9 24 14.54%
Gastropada 0 1 0 4 5 25%
Turbellaria 2 0 0 1 3 17.6%
Gastrotrciha 2 0 0 0 2 28.57%
Insect 0 0 0 0 0 0%

23. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 4
Taxonomic
Composition
S1 S2 S3 S4 Total % Total
Distribution
Nemotoda 6 4 33 141 184 32.2% 57
Poly -chaeta 0 1 0 0 1 33.33% 3
Oligochaeta 0 1 0 2 3 21.42% 14
Foraminifera
8 2 5 6 21 12.1% 174

24. Table 1. taxonomic and Abundance of Mieofauna in the Sedimaent at 4 different depth Layers and
4 sampling stations
LAYER 4
Taxonomic
Composition S1 S2 S3 S4 Total % Total
Distribution
Ostracoda 8 5 1 17 91 55.15% 165
Gastropada 0 0 0 3 3 15% 20
Turbellaria 1 0 0 0 1 5.9% 17
Gastrotrciha 2 1 0 0 3 42.85% 7
Insect 0 0 1 0 1 100% 1

25. CHAPTER IV
RESULTS AND DISCUSSION
The study was conducted in the Rearing Pond 2 of Zamboanga
State College of Marine Sciences and Technology (ZSCMST) during the
month of December to February 2011. Collection of samples were made
at daytime and it was about 7:00 o’clock in the morning in January3,
2011. A total of nine (9) taxa were identified in the entire duration of the
study (see Table1) these are; Nematoda, Foraminifera, Ostracoda,
Oligachaeta, Gastropoda, Turbellaria, Polychaeta, Gastrotricha, Insecta
including Fish Larvae. Four (4) were observed to be constantly present
in all four (4) Layers (0-2 cm, 2-4cm, 4-6cm, 6-8cm) and four (4)
sampling stations.
Oxygen availability is one of the main factors that condition the
vertical distribution of Meioauna (Coull, 1988), The Nematoda were the
dominant group in this stady and several studies reported that Nematoda
is the most dominant taxa in the sediments (Rao, 1987; Lee et al, 2003;
Higgins and Thiel, 1988 and http://www.uft.uni-
bremen.deoekilogieMeiofaunaReport.pdf, 2006) (as stated in Chapter 2)
As we can see in Table 1, Nematoda group in the fourth Layers
(station 4) show a high densities and according to Franz Rieman, 1979,
many nematodes do not need a rich oxygen supply and maybe regarded
as facultative anaerobes, so it is possible to find nematodes in the deeper
layers.

26. The oxygen availability limits the distribution of several
meiobenthic groups that can be found almost exclusively in the
first layer (2cm) depth, (Oligachaeta, Foraminifera, Ostracoda,
Gastropoda, Turbellaria). Although the groups Nematoda.
Foraminifera, Ostracode often show higher densities in the first
layer (2cm), they also attain high values and sometimes higher in
lower layers. Apparently, the groups Polychaeta and Oligochaeta
don’t show high densities, since they are active diggers according
to Erseus (1980) they can live at depths greater than 8cm, used in
this study, this can explain why it is not possible to find high
densities.
Coull (1973) emphasized that nematodes regularly dominate
the meiofauna in sediment biotopes comprising 50% of the
meiofauna. He stated further the copepods are usually in the
abundance but may dominate in some course grained sediments.
However, results of this study showed that Foraminifera is the
dominance to nematodes as mentioned in the study of Lee et al,
(2003) followed by Ostracoda and other taxa with a much lesser
abundance.

27. As can be seen in Table 1, the foraminifera were
greater in the first layer, (station 2 and station 4)
decreasing with depth and according to Gooday (1988), the
sarcomastigophora group is generally found near the
sediment surface where they can find nutrients and
interstitial water is well – gerated. Since these organisms
feed on algae (Gooday 1988) and the food availability is
higher on the sediment surface. However, in station 1,
some foraminifers, increase as depth increases, although,
according to Moodley et al (1988) the foraminifers
(Sarcomastigophora) can migrate through anoxic zones
what suggests that some author (1988) the sulphied
concentration (often correlated with the absence of
oxygen) may be important to determine their distribution,
since they tolerate sulphide but only for survival effects, as
they do not reproduce in its presence.