A field trip report on the academic work in the Nijhum Dwip, Hatiya Island

1. Noakhali Science and Technology University
Department of Oceanography
OCN4112
Field Trip
Field Trip Presentation
Location: Nijhum Dwip

2. Objectives of the field trip
 To learn the techniques of field studying.
 To investigate the inter-tidal plant community structure.
 To learn how to collect soil sample using hand augur.
 To collect and preserve the benthos sample from the inter-tidal zone.
 To collect, preserve sample of phytoplankton and zooplankton.
 To learn how to assess different water quality parameters (e.g., dissolved oxygen,
pH, electrical conductivity).
 To know physical, socio economic and cultural aspect of the study area, to know
about the life and livelihood of coastal community.

3. Methodology of the field study
Choosing a study
topic
Literature Review
Formulating problem
for the study
Data collection
Choosing variables
Sorting necessary
information
Data Analysis and
interpretation
Drawing conclusion
& recommendation
Documentation
Report Presentation
Site Selection
Before Field Study During Field Study After Field Study Outcome

4. Nijhum Dwip: The Island of Silence
 An accreted island, with a total area of about 40390 ha, lies in the central coastal zone of
Bangladesh.
 An island with intertidal mudflats, and sand-flats of 20 kms long sandy and grassy beach.
 The forest area is about 9000 acres and is host of diverse species. The forest bed is muddy and
inundated by tidal actions twice in a day.
 Vibrant biodiversity allowed Nijhum Dwip to be listed as a wetland of international importance.
 Declared as National Park of Bangladesh in 2001.
 Declared as Nijhum Dwip Marine Reserve/ Marine Protected Area (MPA) in 2019. The declared
protected area covers 3,188 square kilometers of estuarine waters at the mouth of the world’s
third largest river system: the Padma- Jamuna Meghna and offshore of the Nijhum Dwip National
Park.

5. Study area map
Fig. 1. (a) Location of Hatiya Upazila in Bangladesh (b) Location of the study area (c) Study Area map showing major features of Nijhum Dwip island.

6. Nijhum Dwip: The Island of Silence
 A unique assemblage of marine, brackish and fresh water ecosystem with estuarine characteristics,
with a highly productive ecosystem for fisheries resources.
 Flora: Mangrove plantation started in 1973 with Sonneratia apetala (keora) (80%) and Avicennia
officinalis(baine) (15%) that covered the northwest part of the island. The Keora (or Kerfa) tree was
chosen for its fast growing root system, which anchors itself into the sandy ground. The ecosystem
is biologically diverse with 68 plant and 66 animal species (Rosario, 1997).
 Changes in temperature, even small changes in water temperature, are expected to exert strong
pressure upon fish ecology (WWF 2005).
 Climate: Moist tropical maritime climate
 Temperature: Ranges from 16ºC to 33ºC (BBS 2011).
 Humidity: Ranges from 29% to 99% (BBS 2011).
 Rainfall: Frequent. Heavy during the monsoon (May to October); 140 mm to1040 mm.

7. Activities
7
1 3 5
6
4
2
Assessment of intertidal
plant community structure
Zooplankton Sample
Collection
Groundwater (tube-well)
quality assessment
Phytoplankton
Sample Collection
Intertidal benthos sample
collection method
Soil sample collection
with hand augur

8. Activity 01
Assessment of intertidal plant community structure

9. Intertidal Plant Community Structure
 The plant which found on the area of the ocean
between the high tide and low tide lines, usually on
the beach at the water's edge this plant known
intertidal zone plant.
 These plants are submerged with water during high
tide and exposed to the air during low tide.
 The intertidal zone of this island generally combined with mudflats and
sandflats. In Bangladesh an assessment of plant diversity of different
national parks and wildlife sanctuary are already being started.
 There were no assessment records of intertidal plant diversity were
found for Nijhum Dwip except few plant names in the forest
management plan
Figure: Inter-tidal zone.

10.  Plant data collections of the study area have been done March, 2020.
 Quantitative data collection has been collected from eleven different sampling point on Nijhum
Dwip Island.
 These sampling point have been selected around 100m.
 In order to know the frequency of ground vegetation, data have been collected different three
point by using 1x1m quadrate from the same sampling points.
Sample Collection Method and Materials:
 These points have been taken at a certain distance to get vertical.
 The collection has been between intertidal zone included with mud,
sand and mangrove sight.
Figure: Plant community study using quadrate
method on the Nijhum Dwip

11. Study area map for Plant community assessment
Figure: Study area map for Plant community collection.

12. Pictures of work
Figure: Plant species observed using quadrate method on the Nijhum Dwip

13. For each species local name, scientific name, family, habit are provided in table.
Species Identification
Attribute Habit Local Name Scientific name
Picture
Family Poaceae Amananthace Astaraceae
Habit Herb Shrubs Herb
Local Name Durba Grass Bathua -
Scientific name Cynodon dactylon Cenopodium album Enhydra fluctuans

14. Attribute Habit Local Name Scientific name
Picture
Family Convolvulaceae Zosteraceae Poaceae
Habit Herb Herb Herb
Local Name Kalmi shak - chapra
Scientific name Ipomoea aquatic Zoster marina Eleusine indica
Species Identification

15. • From the collected photographs, six species of plants were identified.
• Among the species, 1 are represented by shrubs, 5 by herbs. Poaceae is the dominant family in
Monocotyledon having 2 species.
Plant Community
Composition
Shrubs Herbs
0 1 2 3
Poaceae
Amananthaceae
Astaraceae
Convolvulaceae
Zosteraceae
Distribution of Plant Family
Result:

16. Interpretation
For our selected study area, our collected sample
shows herb as the dominant plant and Poacae as the
dominant family among the samples. However, our
derived result does not presents the ideal scenario for
the whole island. As we sampled from only one side
of the island and not randomly. Our aim was to learn
the sample collection and identification technique.
A previous study showed relevant scenario (Figure
below) for the island, a total of 152 plant species
under 56 families has been recorded from Nijhum
Dwip. (Ara et al. 2013).
Poaceae
8%
Fabaceae
7% Mimosaceae
5%
Asteraceae
5%
Euphorbiaceae
5%
Moraceae
4%
Amaranthaceae
4%
Verbenaceae
4%
Arecaceae
3%
Caesalpiniacea
3%
Acanthaceae
3%
Other 44
families
49%
Fig. Distribution of species in the families
0
10
20
30
40
50
60
70
Number of species
Fig. Different life forms of plant species

17. Activity 02
Phytoplankton Sample Collection

18. Phytoplankton Collection
Phytoplankton Collection Procedure:
Phytoplankton are autotrophic organisms and are primary producers of an ecosystem. Primary
productivity influences the availability of fisheries resources in a particular region. Collection of
plankton sample and species identification indicates plankton species composition in a
particular area, which provides significant insights about the primary producer’s distribution,
abundance etc.
1. We selected suitable sampling stations (marked on map).
2. We collected water sample from surface layer using a bucket, then poured it into plankton
net and filtered. The cod end was closed.
3. After that we collected final water sample caught by the cod end.
4. Then we collected final samples in plastic bottles and labelled with station no.
5. Preservation: 10% formalin (Methyl alcohol) to preserve these samples
6. We also measured environmental parameters such as water Temperature, Dissolved oxygen
(DO), pH , salinity, Total Dissolved solis (TDS), Transparency
7. Specices identification were performed in the laboratory.

19. Figure: Study area map for phytoplankton and zooplankton collection
Study area map for
Phytoplankton
and Zooplankton
collection.

20. Measured Physiochemical Parameters
Figure: Graph showing physiochemical parameters (a) water Temperature, (b) Dissolved oxygen (DO), (c ) pH measured at the sampling stations.

21. Measured Physical Parameters
Figure: Graph showing physiochemical parameters (d) salinity, (e) Total Dissolved solis (TDS), (f ) Transparency measured at the sampling stations.

22. Attribute No. 1 No. 2 No. 3 No. 4
Picture
Scientific Name Anabaena sp Coscinodiscus sp Euglena sp Nostoc sp
Group Anabaena Coscinodiscus Euglena Nostoc
Class Cyanophyceae Coscinodiscophycea
e
Euglenoidea Cyanophyceae
The collected samples were identified following the book titled
Table 3: List of phytoplankton group are presented in the following table.
Species Identification

23. Photos of work

24. Activity 03
Zooplankton Sample Collection

25. Zooplankton Collection
Zooplankton Collection Procedure:
The zooplankton assemblage is a sensitive indicator of the ecological status of an aquatic ecosystem since it
can respond to environmental changes with rapid modifications in the species composition and structure.
The zooplankton population can reflect the nature and potential of any aquatic systems. They are
represented by a wide array of taxonomic groups viz., Protozoa, Cladocera, Copepoda and Rotifer in a
freshwater ecosystem that is often armored by different organs like spines from the predator.
1. We decided to collect sample from six stations.
2. We used plankton net (90 µm mesh size).
3. Zooplankton samples were collected from a depth of 5-10 cm below the water surface in the
morning hour (7-9 AM), Noon hour (12-2 PM) and after noon hour (5-7 PM)

26. Sampling and Collection .
1. Firstly, we took water from surface layer using one little mug.
2. Then we poured it into plankton net and it filter water. Cod end was closed.
3. After that we collected final water sample caught by cod end.
4. Then we took these samples in plastic bottles with 10% formalin on site and labelled.
5. Then transfer to the ice box and finally conducted in laboratory of Oceanography, Noakhali
Science and Technology University.
6. We also measured environmental parameters such as pH by pH meter, Salinity by
refractometer, temperature by thermometer, TDS, DO.
Preservation
We used 10% formalin (Methyl alcohol) to preserve these samples. After that we transferred
these to laboratory for analysis.

27. Figure: Study area map for phytoplankton and zooplankton collection
Study area map for
zooplankton
collection.

28. Sl No Group Scientific Name Picture
01 Copepoda Cyclops vernalis
02 Cladocera Diaphanosoma sp
03 Larva Nauplius sp
04 Rotifera Brachionus sp
05 Rotifera Rotifer sp
Species Identification

29. Activity 04
Intertidal benthos sample collection method

30. Inter-tidal Benthos organisms
Benthos are organisms that live on or in the bottom of a body of water, such as Worms ,
clams ,crabs, lobsters ,sponge , snails , kelp etc.
Divided different size range:
• Macrobenthos :larger than 1 mm (0.04 inch) which are dominated by polychaete worms,
pelecypods, anthozoans, echinoderms, sponges, ascidians, and crustaceans
• Meiobenthos : 0.1 and 1 mm in size, include polychaetes, pelecypods, copepods,
ostracodes, cumaceans, nematodes, turbellarians, and foraminiferans.
Intertidal zone is exposed to the air at low tide and underwater at high tide; areas include
many different types of habitats, including steep rocky cliffs, sandy beaches, or wetlands

31. Sampling site
• It is located at northern
part of the Nijhum Dwip
Island.
• Tidal influence is active
here.
• Salinity: from 11-11.5 ppt
• Temperature 26.5-27°C.
• Samples were collected
from clay bottom area.
• It is subjected to high
erosion and water body is
turbid.
Figure: Study area map for benthos collection.

32. Sample Collection
• Four working stations were selected in different parts of Nijhum Dwip Island.
• Each station was divided into three sub-stations (sub-station=01, sub-station=02 and
substation=03).
• Three replicate soil samples were collected from each station with hand. Replicate
samples were taken from intertidal area of the stations.
• Sediment samples were transferred into bucket and mix with water properly; mixed
water passed through a hand-sieve with 0.5 mm mesh.
• Then these sieved organisms were taken into plastic bottles and marked over the
bottle by a marker pen.

33. Photos of work
Photo credit: Ananya Bhuiya

34. Group Feature Example
Polychaeta • Metamerically segmented, Bilateral symmetry.
• Chitinous setae called parapodia.
• Closed circulatory system.
• Complete digestive system.
• Respiration through skin, gills.
• Nephridia for excretion.
Polychaeta sp
Oligochaeta • Hermaphroditic; Segmented body.
• Terrestrial or freshwater habitats.
• Specialized structure of alimentary and reproductive system.
Lumbricus terrestris
Crab • Decapod, 10 legs; Hard Exoskeleton.
• Double Antennae. Most crabs have two pairs of antennae.
• Sideways Walking; Land and Water Breathing.
Ocypode macrocera
Amphipoda • Body slender shaped, laterally compressed.
• Thorax and abdomen are usually quite distinct.
• Compound eyes are sessile
Talitridae sp
Table: List of benthos in the intertidal zone of Nijhum Dwip.

35. Activity 05
Groundwater (tubewell) quality assessment

36. Apparatus: Multi-probe
Procedure:
•Initially, Calibrated for each probe for the measuring time (conductivity, pH and
dissolved oxygen).
•Rinse with deionized (DI) water between each calibration
•We measured conductivity and then used a calibration solution
•Then pH, use 2-point calibration that buffers the expected measurement
•Temperature cannot be calibrated, but is good to do a check against a NIST certified
thermometer to make sure the equipment is working properly.
Assessment of physio-chemical parameters of Tube-well water

37. Physiological parameters Measurement
Salinity (ppt) 11.5
pH 7.7
Eclectic Conductivity (EC) 796.8
Temperature 24.6
Table: List of Physiological parameters are present in the
following table.
• Turn on the multiprobe and position the
meter in the thalweg (main stream flow); or
along a bank/edge in the flow if the
waterbody is too deep or fast; or lower from
a bridge.
• Ensure the measurements are upstream of
other sampling activity, in well mixed water
and avoid disturbing bottom sediments.
• Wait 1 - 2 minutes for the values to settle and
record them on the data sheet provided.
When finished sampling, rinse gently and store the probes properly
Data Collection

38. Add pictures of work!!
Picture of work
Figure: One of our mate measuring water quality parameters using multi-probe
from the collected tubewell water sample in a bottle.

39. Activity 06
Soil sample collection with hand augur

40. This system uses an auger, a series of extension rods, a “T” handle, and a thin-wall tube sampler.
The auger bores a hole to a desired sampling depth and then is withdrawn. The auger tip is then
replaced with a tube core sampler, lowered down the borehole, and driven into the soil at the
completion depth.
Hand Augur
Figure: a) Hand augur, b) how augur works
(a)
(b)

41. I. Insert the auger into the material to be sampled at a 0o to 45o angle from vertical. This
orientation minimizes spillage of the sample from the sampler.
II. Extraction of samples may require tilting of the sampler. Rotate the auger once or
twice to cut a core of material.
III. Slowly withdraw the auger, making sure that the slot is facing upward.
IV. An acetate core may be inserted into the auger prior to sampling, if characteristics of
the soils or body of water warrant. By using this technique, an intact core can be
extracted.
V. Transfer the sample into an appropriate sample or homogenization container.
Sample collection procedure:

42. Picture of work
Figure: One of our mate collecting soil sample using hand augur.

43. Other observations
Photo credit: Jahirul Islam
Collected from internet
Nijhum Dwip is a place of tourist attraction, one
of the reason is, due to deers.
At present the island is habitat of around 3000 deers.
(Source: News portal)

44. Life and
Livelihood
Photo credit: Ananya Bhuiya

45. Conclusion
The field trip is the vast of sagacious practices and it is the
consummate way to appropriately erudite afford. Our study, we
identified four species of benthos (Polychaeta sp, Lumbricus terrestris
Ocypode macrocera, Talitridae sp), four species of phytoplankton (such
as Anabaena sp, Coscinodiscus sp, Euglena sp, Nostoc sp), five species of
zooplankton (such as Cyclops vernalis, Diaphanosoma sp, Nauplius sp,
Nauplius sp, Rotifer sp), and A total of seven plant species under five
families have been recorded from Nijhum Deep in Intertidal zone
such as Eleusine indica, Zoster marina, Ipomoea aquatic, Enhydra
fluctuans, Cenopodium album, Cynodon dactylon.

46. References
• Boyd,C.E.,1982. Water Quality Management of Pond Fish Culture. Elsevier Science Publisher
Company, Amsterdam, Oxford, New York, pp:318
• Hossain. M.Y., S. Jasmine, A.H.M. Ibrahim, Z.E. Ahmed and J. Ohtomi et al.,2007. A
preliminary observation on water quality and plankton of an earthen fish pond in
Bangladesh :Recommendations for future studies. Pak.J.Biol.Sci.,10:868-873.
• Mridula, R.M. and K.M. Rajesh,2002. Ecology of phytoplankton in the coastal waters of
Mangalore, West coast of India. Bangladesh J.Fish.Res.,6:165-172.
• Asadujjaman M, Hossain M B, Shamsuddin M, Amin M A, Azam A K M. 2012. Occurrence
and abundance of macrobenthos of Hatiya and Nijhum Dweep Islands, Bangladesh. Middle-
East J. Sci. Res, 11(2): 184–1884.
• M. Belal Hossain, S.M.N. Amin, M. Asadujjaman and Sharmeen Rahman, 2013. Analyses of
Macrobenthos of Hatiya and Nijhum Dweep Islands at Higher Taxonomic Resolution. Journal
of Fisheries and Aquatic Science, 8: 526-534.

47. References
• Alam, M.S., 1993. Ecology of the Intertidal Macrobenthos of Halishahar coast, Chittagong,
Bangladesh. PhD. Thesis, Department of zoology, University of Chittagong, Bangladesh, pp:
243.
• Chowdhury, M. S. A., Uddin, N. M., Imran, M., Hassan, M. M., & Haque, M. E. (2004). Parts
of speech tagging of bangla sentence. In Proceeding of the 7th International Conference on
Computer and Information Technology (ICCIT).

48. Team Presentation
48
Azad Uddin Sojib
ASH1818010M
Md. Soliman Hossain
ASH1718014M
Shammitul Shiropa
BKH1718015F
Md. Millat Hossain
ASH1718018M
Barna Rani Paul
BKH1718021F
Ananya Bhuiya
MUH1718027F
Md. Jahirul Islam
ASH1718030M

49. Thanks for your time.