The international conference on natural sciences and environment 2020 Kỹ yếu hội thảo Quốc tế

The International Conference on
Natural Sciences and Environment 2020
December 27th, 2020
Dong Thap University, Vietnam

Conference Schedule
Time
7h30 8h00

Contents

Presenters

Registration
Dr. Vu Thanh Binh

8h00 8h10

8h10 8h20
8h20 8h30

Deputy Director General,
Department of Science, Technology
and Environment, Vietnam

Welcoming Remarks

Dr. Marilyn Cardoso
Welcoming Remarks

President of Samar State University,

the Philippines

Assoc. Prof., Dr. Pham Minh Gian
Opening Remarks

Vice Rector of Dong Thap University,
Vietnam

Assoc. Prof., Dr. Tran Van Tan
8h30 8h40

Orientation Speech

8h40 9h00

Presentation 1: New Research in
Assoc. Prof., Dr. Huynh Vinh Phuc
Physics

9h00 9h10

Discussion

9h00 9h20

Presentation 2: Heavy Metals in Dr. Ariel B. Mabansag
College of Education, Samar State
Commercial Shrimps in Samar Sea

9h20 9h30

Discussion

9h30 9h50

Presentation 3: Study on Sars-Cov-2
Inhibition Ability of Compounds in
Cymbopogon Citratus Oil Using
Quantum
Chemical
Calculations,
Simulation Techniques

Department of Natural Science
Teacher Education, Dong Thap
University, Vietnam

Department of Natural Science
Teacher Education, Dong Thap
University, Vietnam

University, the Philippines

Dr. Ariel B. Mabansag;
Assoc. Prof., Dr. Tran Van Tan

1

Dr. Bui Thi Phuong Thuy
Faculty of Basic Sciences, Van Lang

University, Ho Chi Minh City,
Vietnam


9h50 10h00

Dr. Bui Thi Phuong Thuy;

Discussion

Assoc. Prof., Dr. Tran Van Tan

10h00 Photo session and Coffee break
10h20
Presentation 4: Carbon Dioxide and
10h20 - Sea Surface Temperature as Predictor
10h40 of Coral Reef Bleaching Occurrence
and Severity Levels

Dr. Diana Shane A. Balindo

10h40 Discussion
10h50

Dr. Diana Shane A. Balindo;

University of San Carlos, Cebu City,
CFARRD - Samar State University,
the Philippines

Assoc. Prof., Dr. Tran Van Tan

MSc. Nguyen Ho
Presentation 5: Monitoring 15-Year Department of Land management,
10h50 Land Use/Land Cover Change in The Faculty of Agriculture, Natural
11h10
Resources and Environment, Dong
Vietnamese Mekong Delta
Thap University, Vietnam

MSc. Nguyen Ho;

11h10 Discussion
11h20

Assoc. Prof., Dr. Tran Van Tan

Presentation
6:
Theoretical
Investigations on The Molecular
Structure, Vibrational Spectroscopy,
11h20 AIM, NBO, MEP, and HOMO-LUMO
11h40
Analysis of Benzoic Acid Monomer
and Dimer Based on Density
Functional Theory

Institute of Research and Applied
Technological Science (IRATS),

Dong Nai Technology University,
Vietnam

MSc. Truong Tan Trung;

11h40 Discussion
11h50
11h50

MSc. Truong Tan Trung

Assoc. Prof., Dr. Tran Van Tan

Wrap-up and Closing

2


TABLE OF CONTENTS
Ariel B. Mabansag*, Mary Rose M. Briones, and Engr. Esteban A.
Malindog Jr. Heavy Metals in Commercial Shrimps in Samar Sea

5

Diana Shane A. Balindo. Carbon Dioxide and Sea Surface Temperature as
Predictor of Coral Reef Bleaching Occurrence and Severity Levels

13

Nguyen Ho*, Phan Van Phu, and Nguyen Thi Hong Diep. Monitoring 15Year Land Use/Land Cover Change in The Vietnamese Mekong Delta

26

Lam Kim Nhung, and Nguyen Minh Hieu. Payments for Coastal and
Marine Ecosystem Services: Lessons from Previous Experiences

37

Vo Thi Phuong*, Nguyen Du Sanh, Huynh Thi Thanh Truc, Nguyen
Thi Huynh Nhu, Pham Thi Thanh Mai, anh Nguyen Thi Be
Nhanh. A Study on The Effects of Water Submergence Depth on The
Formation of Eleocharis Ochrostachys Steud. Tuberization in
Experimental Conditions

53

Jessa B. Madera*, Diana Shane A. Balindo, Zhereeleen MenesesAdorador, and Jiro A. Adorador. Spatial Distribution of Threatened
Species‟ Mother Trees in Selected Forests over Limestone in Samar
Island, Philippines

67

Nguyen Thi Dan Thi. Surveillance of Quality of Petunia Hydrida over
Generations of Cutting

101

Nguyen Van Tho*, Huynh Phan Khanh Binh, and Tran My Vien.
Assessment of Seafood Processing Sludge after Composting on Growth
of Tagetes patula L.

111

Nguyen Thi Thanh Nhan. Plastic Pollution in The Marine Environment
and Its Impacts on Marine Biodiversity in Vietnam

120

Bui Thi Phuong Thuy, Ta Trung Can, Bui Thi Bao Tram, Nguyen
Huyen Ngoc Tran, Ha Van Chau, Nguyen Minh Quang, Nguyen
Thanh Duoc, and Pham Van Tat*. Study on Sars-Cov-2 Inhibition
Ability of Compounds in Cymbopogon Citratus Oil Using Quantum
Chemical Calculations, Simulation Techniques

128

Nguyen Minh Quang*, Tran Nguyen Minh An, Pham Van Tat, Bui Thi
Phuong Thuy, and Nguyen Thanh Duoc. Calculation of Stability
Constants of New Metal-Thiosemicarbazone Complexes Based on The
QSPR Modeling Using MLR and ANN Methods

141

3


Truong Tan Trung*, Nguyen Ngoc Huong, Nguyen Thi Ngan, and Le
Thi Thu Thuy. Theoretical Investigations on The Molecular
Structure, Vibrational Spectroscopy, AIM, NBO, MEP, and HOMOLUMO Analysis of Benzoic Acid Monomer and Dimer Based on
Density Functional Theory

159

Truong Tan Trung*, Bui Thi Phuong Thuy, Lai Thi Hien,
Nguyen Ngoc Huong, and Le Thi Thu Thuy. Why is Chloroquine as
Inhibitor against Sars-Cov-2 Mpro? Quantum Chemical Insight
Through QTAIM, NBO, FT-IR, HOMO-LUMO energies and
Molecular Docking Modeling Analysis

171

Nguyen Pham Tuan*, Tran Thi Que, Nguyen Hoang Nam, and
Nguyen Hoang Thai. Quantitative Analysis of Diosin in Borassus
Flabellifer L. Flower by HPLC

190

Nguyen Pham Tuan*, Bang Hong Lam, Nguyen Hoang Nam, and
Nguyen Thi Bao Tran. Acute and Subchronic Oral Toxicity of
Cordyceps Miltaris Extract

200

Nguyen Pham Tuan*, Bang Hong Lam, and Nguyen Pham Tu.
Investigation of Factors Affecting the Production of Enzyme Lasparaginase from Aspergillus terreus sf-981 by Solid State
Fermentation

213

Nguyen Pham Tuan*, Bang Hong Lam, and Nguyen Pham Tu.

Inhibition of Calcium Oxalate Crystallisation Causing Kidney Stones
in Vitro by An Extract of Raphanus sativus L. Leaves

228

Nguyen Pham Tuan*, Bang Hong Lam, Nguyen Pham Tu, and Nguyen
Thi Bao Tran. Bioactive Compounds and Antioxidant Activities From
Pomegrante Peel Extract (punica granatum)

241

Nguyen Ngoc Bich*, Nguyen Huu Nghi, and Nguyen Dinh Thanh. Using
Rice Straw to Prepare Magnetic Carbon Material for Arsenic Removal

256

Pham Thi Huong. Re-use Agricultural Resources to Mechanical Filler for
Epoxy Foundation Material

269

Nguyen Phuong Ngoc. Assessment of Current Situation and The Causes of
Air Pollution From The Integration of Traffic and Road System

280

4


HEAVY METALS IN COMMERCIAL SHRIMPS IN SAMAR SEA

Ariel B. Mabansag*, Mary Rose M. Briones, and Engr. Esteban A. Malindog Jr.
College of Education, Samar State University
Catbalogan City, Samar, Philippines 6700
*Corresponding author:
Facebook: Ariel Basal Mabansag
Contact number: +639494799702
Abstract
Maqueda Bay and Samar Sea are important fishing grounds for both municipal
and commercial fishermen in the Eastern Visayas region. Recently however, various
human activities including unregulated fishing and waste disposal have led to the
decline of marine catch due to overfishing and the deterioration of the marine habitat
as a result of pollution. This paper investigated the presence of cadmium and lead in
the tissue samples of three marine shrimps taken from three major landing sites in the
area. The samples were processed using nitric acid digestion and the heavy metal
concentrations were analyzed using Atomic Absorption Spectroscopy (AAS). Lead was
detected in all three shrimp species taken from three sampling sites at significantly
high amounts reaching up to an average of 26.34 mg/kg which is four times the
maximum limit set by Food and Agriculture Organization (FAO). Cadmium was also
detected in the shrimp samples but within the allowable limit set for crustaceans. Twoway analysis of variance showed that the lead concentrations did not differ
statistically among the three species and among the three sampling sites. Cadmium
concentrations differed between two sampling sites but not among the shrimp species.
The presence of heavy metals in shrimp tissues reflects the deteriorating water quality
of the marine habitat in Samar Sea. It significantly impacts on the marine ecosystem
eventually resulting in declining quality of the marine products. This provides a
compelling evidence and a stern warning to maximize efforts in protecting the marine
environment to ensure sustainable marine production.
Keywords: Heavy metals; cadmium and lead; marine pollution; shrimps;
bioaccumulation

5

1. Introduction
Maqueda Bay and Samar Sea are important fishing grounds for both municipal
and commercial fishermen in the Eastern Visayan region. In fact, Samar Province is
known worldwide for its rich supplies of marine products including mussels, oysters,
shrimps and crabs (Diocton, et.al, 2017). These fishing grounds provide a major source
of food and livelihood for the fishermen and its population. These marine
environments are surrounded by several municipalities hence they are directly affected
by anthropogenic activities such as water transportation, seafood farming, and
improper waste disposal from the surrounding communities. The unregulated activities
that contributes to pollution often lead to the deterioration of the water quality leading
to declining catch and increased health hazards to the surrounding population. A study
by Orale and Fabillar (2011) reported improper disposal of waste materials to the
surrounding waters particularly among communities situated along the sea since they
have no direct access to garbage collection services and facilities provided by their
municipalities. Often, rivers, estuaries and marine habitats becomes the ultimate
recipients of manmade pollutants (Chapman, et al., 2013).
Among these pollutants, heavy metals such as cadmium and lead presents the
greatest threat since they can accumulate in the environment and can be transferred
along the food chain and eventually end up being consumed by humans (Hu, et al,
2018). It was previously reported that heavy metal contamination of aquatic
ecosystems has been one of the critical issues in recent years and a growing concern
among many developing Asian countries as a result of rapid economic growth and
increasing population (Agusa, et al., 2007). Heavy metals enter the aquatic ecosystem
from various human activities such as leaching of antifouling paints, oil spills,
leachates from dumpsites, shipping activities, industrial and domestic sewage, and
agricultural use of pesticides and herbicides (Ogundiran, &Afolabi, 2008; Esakku, et
al., 2010; Atafar, Z. et.al., 2010). Assessing the marine ecosystem for potential heavy
metal pollution is essential in managing and maintaining a healthy aquatic

environment.
There are various marine organisms that tend to accumulate heavy metals in their
tissues, hence they are used to assess the presence and abundance of heavy metals in
an aquatic ecosystem (Farias, 2018). This process is called biomonitoring and the
organisms used are called bioindicators (Zhou, 2008). Crustaceans, including crabs
and shrimps have been successfully used as bioindicators particularly in assessing the
presence of contaminants in the marine environment (Baboli, et al., 2013; Yilmaz &
Yilmaz, 2007; Pourang et al., 2005). Shrimps are mostly bottom dwellers and they
tend to scavenge and feed on the residual materials of marine organisms that end up at
the bottom of the sea (Canli, et al., 2001).
There are limited studies conducted related to heavy metal contamination of both
the Maqueda Bay and Samar Sea marine ecosystems. As study conducted by Cebu and
Orale (2017) on the physic-chemical parameters of the green mussel belts in the area
after it suffered mass mortalities in 2007 reported optimum temperature, salinity,
dissolved oxygen and pH levels. Heavy siltations however were observed after heavy
rains as a result of water runoffs from agricultural and household areas. Recurring
cases of harmful algal blooms caused by Pyrodinium bahamense have been constantly
reported and were linked to eutrophication due to increased nutrient and effluent
6


discharge from households and agriculture. Caturao (2001) even linked increased
redtide blooms with heavy metal accumulation in the phytoplankton which reduces the
grazing pressure of zooplanktons.
The abovementioned lack of information on the status of heavy metal
contamination in the two major commercial fishing sites, notwithstanding it potential
hazard to human health warrants that an investigation be conducted to assess their
presence and abundance as reflected in the commercial shrimp samples taken from
the area.
Objectives:

This research aims to determine the presence of heavy metals cadmium (Cd)
and lead (Pb) in commercial shrimps from selected sites in Samar Sea. Specifically,
this investigation aims to
1. Compare the Cd and Pb concentrations from the three (3) commercial shrimp
species, namely Peneaus indicus, Metapeneaus endeavouri, and Peneaus semisulcatus.
2. Compare the Cd and Pb concentrations in the commercial shrimps according
to the location.
2. Methodology
The shrimp samples were collected from three major landing sites of commercial
shrimps in the area, namely: Brgy. Bunuanan, Catbalogan City (Site 1), Brgy. Zone 5,
Paranas, Samar (Site 2) and Brgy. Imelda, Tarangnan, Samar (Site 3). Sampling and
sample preparation were based on different protocols of related studies adopted and
modified depending on the availability of resource.
Sampling
Fresh shrimp samples were purchased from local fishermen on May 2018.
Samples collected were placed in plastic bags, labeled and placed in ice bath (Javaheri,
Baboli and Velayatzadeh, 2013). Samples were subjected to morphological evaluation
using the Field guide for the edible Crustacea of the Philippines by Motoh, H. &
Kuronuma, K. (1980).
Sample Preparation
The shrimp samples were rinsed using distilled water in order to remove debris,
planktons, and other external adherent particles. All shrimp samples were dissected
to separate exoskeleton from muscle (Sharifi, 2017). The samples were drained under
folds of filter, weighed, wrapped in aluminum foil, and then dried at 80˚C in an
electric oven until constant weight was obtained which was done prior to analysis
(Olowu et.al, 2010). After drying, the samples were crushed into fine powder with
an agate mortar and pestles. The powdered samples were transferred into ultra clean
small polyethylene packet (Fatema et al, 2015). Three replicates for each species and
for each sampling sites were taken for laboratory analysis. All other laboratory
procedures including acid digestion, filtration, and heavy metal determination were

carried out according to internationally recognized guidelines (UNEP, 1991).
Pulverized shrimp samples were subjected to heavy metal analyses using Atomic
Absorption Spectrophotometer (AAS) in Visayas State University- Central Analytic
Services Laboratory.
7


Statistical Analysis
The means and standard deviations were used to describe the presence of both
cadmium and lead in the shrimp samples. Two-way Analysis of Variance (ANOVA)
and Tukey‘s posthoc analysis were utilized to determine differences in metal
concentration among the three species and among the three sampling sites including
the interaction effect of these two variables leading to differences in heavy metal
concentrations.
3. Results and Discussion
Cadmium and lead concentrations in shrimp tissues
Table 1 shows the average heavy metal content in the shrimp samples that are
commercially available in the area. Three major shrimp species were used in the
sampling process namely: Peneaus indicus, Metapeneaus endeavouri, and Peneaus
semisulcatus. The results of the heavy metal analyses detected both cadmium and
lead in the shrimp samples. Lead was detected in significantly high amounts in all
shrimp species taken from the three different sites reaching up to 4 times the maximum
recommended limit of 6 mg/kg by the Food and Agriculture Organization (FAO)
(Choi, 2011). Among the three shrimp species, P. indicus recorded the highest mean
lead content at 26.34 mg/kg while P. semisulcatus logged a mean of 14.94 mg/kg
which was still twice the permissible limit set by FAO. On the other hand, cadmium
was also detected in the shrimp samples taken from all three sites. The highest mean
cadmium content was also detected in P. indicus at 0.90 mg/kg while the lowest was
found in M. endeavouri with 0.54 mg/kg. These quantities however were within the
maximum permissible limit set by FAO at 2 mg/kg (Choi, 2011).

Table 1. Average heavy metal concetration according to species
Cadmium

Lead

Species
Mean

SD

Mean

SD

P. indicus

0.90

0.39

26.34

12.51

M. endeavouri

0.54

0.46

18.78

15.81

P. semisulcatus

0.76

0.35

14.94

12.60

Further investigation showed that the shrimps taken from Site 1 have the highest
lead content at 25.49 mg/kg which again exceeded four times the allowable limit set
by FAO for lead content in crustaceans. Site 3 reported the lowest average at 15.96
mg/kg which still exceeded the allowable limit by 2.5 times. On the other hand, the
highest cadmium content was detected from the shrimp samples taken from Site 3 at
0.96 mg/kg while the shrimps taken from Site 2 reported the lowest at 0.43 mg/kg. The
cadmium content however were within the allowable limit set by FAO for crustaceans.

8


Table 2. Average heavy metal concentration according to the site
Cadmium

Lead

Site
Mean

SD

Mean

SD

Site 1

0.81

0.31

25.49

15.02

Site 2

0.43

0.33

18.62

12.91

Site 3

0.96

0.44

15.96

13.94

Comparison of the heavy metal concentration in the shrimp samples
The two-way analysis of variance (Table 3) revealed that there was a significant
difference in the amount of cadmium found in the shrimp samples in terms of the
location (p-value=0.007). This means that the concentration of cadmium varies
significantly with respect to the location. However, the cadmium concentrations did
not differ significantly among the shrimp species (p-value=0.082). Furthermore, the
interaction effect between the species and location was not significant which reflects
that the difference in cadmium in the shrimp tissue can be attributed to the location
only. Meanwhile, the analysis of variance on the lead content in the shrimp samples
did not vary significantly when compared according to the species (p-value = 0.150),
according to the sampling location (p-value = 0.246), or based on the interaction effect
(p-value = 0.069). This suggest that the high lead content found in the shrimp samples
were statistically the same across the shrimp species and across the sampling sites.
Table 3. Analysis of variance test of between-subject effects
Cadmium

Lead

Source
Mean

SE

p-value

Mean

SE

p-value

Species

0.536

0.105

0.082

17.404

3.991

0.15

Location

0.809

0.105

0.007**

14.762

3.991

0.246

Interaction

0.450

0.105

0.134

19.402

3.991

0.069

**. The mean difference is significant at the .01 level
The Tukey‘s post hoc analysis in Table 4, showed that the cadmium detected in
the shrimps taken from Site 3 was significantly higher compared to those found in Site
2 (p-value=0.007). However, this difference is not significant however between Site 3
and Site 1 and between Site 1 and Site 2.

9

Table 4. Mean difference of cadmium concentration in terms of location
(I) Location

Mean
Difference
(I-J)

Std. Error

p-value

Site 2

0.378

0.149

0.052

Site 3

-0.144

0.149

0.605

Site 1

-0.378

0.149

0.052

Site 3

-0.522**

0.149

0.007

Site 1

0.144

0.149

0.605

Site 2

0.522**

0.149

0.007

(J) Location

Site 1

Tukey HSD

Site 2

Site 3

**. The mean difference is significant at the .01 level.
4. Conclusions and Recommendations
The heavy metals lead and cadmium were detected in three commercial shrimp
species from three major locations along Maqueda Bay and Samar Sea. The cadmium
content found in the shrimp species were within the allowable threshold set by FAO.
The quantity of cadmium present in the shrimp samples did not differ across the
shrimp species but it significantly differed based on the location. However lead was
detected at considerably higher levels in the shrimp samples taken from the three
major landing sites exceeding by as high as four times the allowable limit set by FAO.
The quantity of lead in the shrimp samples did not differ significantly across the
shrimp species or across the location. Since there are no mining sites located in the
vicinity, it can be deduced that the heavy metals detected in the commercial shrimps
mostly came from anthropogenic activities.
The presence of heavy metals in the shrimp samples taken from the commercial
fishing grounds in the area reflects the deteriorating quality of the marine habitat. This
has a significant impact on the marine ecosystem which eventually result in the decline
of the quality of the marine products. This provides a compelling evidence and a stern
warning to the local community to maximize its efforts in protecting the marine
environment and to ensure a more sustainable production of marine products. The
local government and the fishing communities in the area should work together to

avoid further deterioration of the marine habitat and make the fishery industry safe and
more sustainable.
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12


CARBON DIOXIDE AND SEA SURFACE TEMPERATURE AS PREDICTOR
OF CORAL REEF BLEACHING OCCURRENCE AND SEVERITY LEVELS
Diana Shane A. Balindo
University of San Carlos, Cebu City
CFARRD - Samar State University, Catbalogan City
Email:

Abstract
Coral reefs and the services it provide are seriously threatened by ocean
acidification and climate change impacts like coral bleaching. Carbon dioxide and sea
surface temperature are the two most important variable in connection to coral
bleaching events. Understanding effects of the two is empirical in uncovering new
information and relationships of bleaching events with local and global environmental
properties (SST and CO2). An exploratory data analysis technique using to
multivariate principal component, cluster, and regression analysis was employed to
characterize the effects of the independent variables on bleaching occurrences. Results
showed that more bleaching occurrences are identified/categorized as medium level of
bleaching severity than bleaching occurrences with high and low severity levels,
respectively. Carbon dioxide also explained a highly significant proportion of
variance in the bleaching occurrence that for every unit increase in CO2, an increase
by approximately 0.0765 units on bleaching occurrence will happen. For every unit
increase in seawater temperature anomalies, a rise by approximately 8.99 units on
bleaching occurrence is expected to occur. Though both does not reveal simultaneous
effects on the occurrence and severity of bleaching events.
Keywords: Coral Bleaching, CO2, Seawater, Temperature

13

1. Introduction
The rising of global temperature due anthropogenic greenhouse gasses has
caused changes in our atmospheric condition, the most unrelenting is climate change.
Global warming is a long term rise of the average worldwide surface temperature
(IAP, 2009). This has been known to cause regional and global statistically identifiable
persistent change in the state of climate that may last for a time. Global warming has
been a reoccurring natural phenomena of the Earth‘s history. However, in the Fifth
Assessment Report of the Inter-Governmental Panel on Climate Change (IPCC, 2014)
recognized the likelihood that human influence has been the foremost cause of the
phenomena in since the mid 20th century. The most evident human activity that have
been pointed out as culprit is the emission of greenhouse gasses in the likes of carbon
dioxide, methane and nitrous oxide, thus calling the recent warming as anthropogenic
global warming.
Global warming induced climate change affects our physical and biological
environment and it has been acknowledged that it is one of the most prevalent among
different threats to biodiversity (Dawson et al., 2011; Malcom et al., 2005; Kappelle
1999). It influences biodiversity directly and indirectly thus a need for adaptation
through shifting habitats, changing life cycles or developing new physical trait is
essential (Pereira et al., 2012; Parmesan and Yohe, 2003; Vittoz, 2013). Its effects has
been stablished to be persistent even in inaccessible areas far from human habitation.
Generally organisms and ecosystem hotspots are susceptible to the effects of
anthropogenic activities. Moreover this vulnerability is exacerbated with the existence
of climate change. Organism‘s inability to migrate and rapid change and loss of habitat
magnify the vulnerability to extinction. Many of these characters that makes species
susceptible to extinction correspondingly increases its risk to impacts of climate
change (Stanton et al., 2015; Foden et al., 2008). Cases of this kind was also observed
even in non-hotspot areas of the planet living us into conclusion of the global nature of
the threat of climate change.

Organisms that accumulate calcium carbonate structures are particularly
vulnerable to ocean warming and ocean acidification. This phenomenon are potentially
reducing the socioeconomic benefits and ecosystem services of the ecosystem reliant
on these taxa. Coral reefs the ―rain forest of the sea‖ have been known to be one of the
foremost ecosystem directly affected by climate change. This has been evident in the
large scale mortality due to bleaching (Bellwood et al., 2004). Global warming is
expected to compound the effects of climate change in the tropical seas in terms
temperature and acidity resulting to coral bleaching occurrence and different
severities, reducing coral growth and reproduction (Brown and Ogden, 1993; Bruno
and Selig, 2007; Marshall and Baird, 2000). Consequently changes the patterns of
distribution, abundance, species diversity, and general ecological function HoeghGuldberg, 1999; Hughes et al., 2003).
2. Objectives
The main objective of this study is to determine and characterize the effect of
CO2 and sea -surface temperature anomalies on bleaching occurrence and its level of
impact on bleaching severity and understand the similarities in the bleaching
occurrence and severity levels. By uncovering new information and relationships of

14


bleaching events with local and global environmental properties (SST and CO2), we
make assumption about the ecosystem responses that can serve as tool in data analysis
design to uncover the concepts within the information/previous data and improve the
capacity to predict the effects of future extreme events.
3. Methodology
This paper utilizes data mining, which is commonly called exploratory data
analysis technique. It is the means of eliciting previously unknown, valid and
actionable information from a range of databases and utilizing this information to yield
meaningful explanations on environmental factor changes and interactions. This
advanced methods of data analysis technique aimed at uncovering new information or

a validation of a previously crafted hypothesis. It performs pattern recognition and can
serve as statistical tools to support advanced data analysis design to uncover the
principles/concepts within the information.
This study used the following variables obtained from reliable sources, namely
carbon dioxide information, seawater temperature changes and bleaching occurrence
in seawaters. the mean temperature data (1950-2018) was derived from the National
Center
for
Environmental
Information
of
USA
( Global
coral
bleaching data was derived from WorldfishDataverse of Harvard University
Dataverse. Atmospheric carbon dioxide data in parts per million was derived from Our
Worl in Data Org. These variables are considered indicators of climate change and
bleaching occurrence and severity levels in seawaters among selected regions in the
world. The selected regions for the location of seawaters are composed of Eastern
Africa, Southwest Indian Ocean, Persian Gulf, Red Sea Gulf of Aden, North and ast
Asia, South Asia, Southeast Asia, Papua New Guinea, Micronesia, Southeast and
Central Pacific, Southwest Pacific and US Pacific Islands with data sets obtained
inclusive of time-periods from 1979 to 2012 except 1982 and 1988.
Retrieval of data sets were done through browsing different reliable world
environmental statistics sources. The researcher then compiled and organized the
gathered data in order to determine the indicators vis-a-vis the twelve selected regions
for the location of seawaters.
The data sets of the identified variables were subjected to multivariate principal
component, cluster, and regression analysis. Multivariate principal component analysis
was used to depict the weight contributions on various categories bleaching severity

types based on bleaching occurrence in sea waters of selected regions in the world.
Cluster analysis was used to identify time-periods (in years) showing similarities in the
bleaching occurrence and severity levels, CO2 (ppm) and sea water temperature
anomalies among selected regions for the location of seawaters in the world.
Consequently, bivariate and multiple regression analysis were utilized to determine
and characterize the effect of CO2 ppm and sea water temperature anomalies on
bleaching occurrence in sea waters and its level of impact on bleaching severity in the
chosen regions.

15


4. Results and Discussion
The following results show the clustering of time-periods in years depicting
similarities in CO2 ppm, sea water temperature anomalies, bleaching occurrence and
bleaching severity among selected regions, namely, Eastern Africa, Southwest Indian
Ocean, Persian Gulf, Red Sea Gulf of Aden, North and East Asia, South Asia,
Southeast Asia, Papua New Guinea, Micronesia, Southeast and Central Pacific,
Southwest Pacific and US Pacific Islands with inclusive time-periods from 1979 to
2012 except for 1982 and 1988. Bleaching severity level is determined by means of
multivariate principal component analysis depicting the weight contributions on
various categories bleaching severity types. The resulting model that characterize the
bleaching several level is shown in the following results.
Table 1: Eigen analysis of the Correlation Matrix

Results reveal that the first eigenvector or principal component represents
70.70% of the total variance. This finding is sufficient to represent bleaching severity
index among selected regions across time-periods from 1979 to 2012 except 1982 and
1988, considering the four different types of severity levels such as high, medium, low
and unknown.

Table 2: Weight contributions of various levels of bleaching severity types

Table 2 shows that the bleaching severity among selected regions across timeperiods varies directly with the four levels of bleaching severity categories. The model
below depicts the weight contributions of various types of bleaching severity levels.
Bleaching Severity Index=0.582High+ 0.589Medium + 0.561Low + 0.000 Unknown
The model further revealed that the bleaching severity among selected regions
across time-periods is mainly characterized by medium categories, followed by high and
low levels of severity types. This implies that more bleaching occurrences are
identified/categorized as medium level of bleaching severity than bleaching occurrences
with high and low severity levels, respectively. This result is in accord with previous
studies on prediction and modeling of coral bleaching frequencies and magnitude.
On the study of Donner et al (2005) it was predicted that the frequency of
bleaching occurrences in most regions of the tropics will be lower and that their
model shows that low intensity bleaching will occur once in every 2 years throughout
each of the major tropical ocean regions. In another study, Guest et al. (2011) outlined
the observation that most taxa of corals in Singapore and Tioman Island bleached in
much less severity with only few mortality in 2010.

16


Figure 1: Dendrogram of time in years from 1979 to 2012 depicting similarities in
CO2(ppm), sea water temperature anomalies, bleaching occurrence and bleaching
severity among selected regions in the world
Table 3: Final Partition (Number of clusters: 4)

Banking on the hypothesis that corals still have the capacity to adapt to increasing
sea temperatures, it was projected that species that have previously encountered major
bleaching will have the utmost increase thermal tolerance (Maynard et al., 2008).
Moreover, reefs in more thermally unstable locations will bleach in less magnitude in

times of elevated sea temperatures (Oliver and Palumbi, 2011).
Results revealed that during time-periods, 1979 (1), 1980 (2), 1981 (3), 1984 (5),
1985 (6), 1986 (7), 1987 (8), 1989 (9), 1990 (10), 1991 (11), 1992 (12), 1993 (13),
1994 (14), 1995 (15), 1996 (16), 1997 (17), and 1999 (19) (cluster 1) showed
similarities in CO2, sea water temperature anomalies, bleaching occurrence and
bleaching severity among selected regions in the world. During 1998 (18) (cluster 2),
the CO2, sea water temperature anomalies, bleaching occurrence and bleaching
severity among selected regions are found to have unique levels for this single time
period. Cluster 3, which is composed of time periods 2000 (20), 2001 (21), 2005 (25),
2006 (26), 2007 (27), 2008 (28), 2011 (31) and 2012 (32) depicts other class of
similarities in CO2 in ppm, sea water temperature anomalies, bleaching occurrence and
bleaching severity levels. Consequently, cluster 4 that includes time-periods, 2002

17


(22), 2003 (23), 2004 (24), 2009 (29) and 2010 (30)) showed further unique levels in
CO2, sea water temperature anomalies, bleaching occurrence and bleaching severity
among selected regions of the world.
Cluster 1 showed the least bleaching occurrence and bleaching severity levels with
minimal CO2 and seawater temperature anomalies during these time-periods as
compared to the other three clusters. On the other hand, cluster 2, which is composed of
a single time-period (1998), revealed a highly severe bleaching occurrence with
relatively high CO2 and seawater temperature anomalies. Coral cover in Western Indian.
Table 4: Cluster Centroids on CO2 ppm, seawater temperature anomalies, bleaching
occurrence and bleaching severity levels among selected regionsin the world.

Table 5: Analysis of Variance results showing the effects of CO2 ppm and sea water
temperature anomalies on bleaching occurrence

Ocean decline across 1998 climatic oscillation that massively and severely
affected the areas of India, Sri Lanka, Maldives and Granite Seychelles (Ateweberhan,
and McClanahan, 2010). Cluster 4 is depicted to have relatively high bleaching
occurrence and bleaching severity next to cluster 3 with relatively high CO2 and sea
water temperature anomalies. Cluster 3 time-periods is deduced to have the highest
CO2(ppm) and sea water temperature occurrence and has a medium severity level of
bleaching occurrence.

18


Effects of CO2 and
Occurrence

Sea Water Temperature Anomalies on Bleaching

The regression analysis results given in Table 5 and 6 as well as Figure 2 below,
determines the joint effects of CO2 ppm and sea water temperature anomalies on
bleaching occurrence among sea waters in selected regions in the world.
Table 6: Coefficients depicting the effects of CO2 ppm
and sea water temperature anomalies on bleaching occurrence

Figure 2: Normality Test Results on Standardized Residuals of Bleaching Occurrences

The results show that the CO2 significantly predicted the bleaching occurrence
for long- time-periods among coral reef areas of selected regions in the world
(  0.0765, t  4.000, p  0.000) . However, seawater temperature anomalies revealed
no simultaneous effect on bleaching occurrence, (  0.64, t  0.25, p  0.807) .The
carbon dioxide also explained a highly significant proportion of variance in the
bleaching occurrence in the sea waters among selected regions in the world (

r 2  63.32%, F2,29  25.04, p  0.000 ). That is, for every unit increase in CO ,
2

an increase by approximately 0.0765 units on bleaching occurrence will happen.
Previous studies have showed the sensitivity of corals with the levels of both
atmospheric and dissolved levels of carbon dioxide. Studies of Langdon, C. &
Atkinson and Schneider, K. &Erez, J (2005; 2006) showed that warm-water
zooxanthellae bearing corals demonstrate a high degree of sensitivity to declining
19


seawater pH.The principal concern about CO2- induced ocean acidification is on
impending effects rates of biogenic calcium carbonate production by corals and
coralline algae, the dominant reef calcifiers for marine ecosystem. A study on a
northern Red Sea reef modeled from a community calcification to aragonite a global
shift from net accreting to dissolving when atmospheric carbon dioxide reaches 560 pp
(Silverman et a;., 2009). Studies of Gattuso et al., Langdon et al., Marubini&
Atkinson, and Marubini& Davies (1998; 2000; 1999; 1996) to test the impact of
atmospheric CO2 showed potentially dramatic responses in corals and reef
communities (Langdon et al. 2000).
Congruent to the study of Hoegh-Guldberg et al. (2007) it clearly showed that
coral reef is sensitive to carbon dioxide level, acidification and thermal stress.
Nevertheless, the impact of this effects will not occur simultaneously and uniformly in
space and time across the worlds coral reef areas (Pandolfi et al., 2011; Albright et al.,
2013). Reasons why effect of both temperature and CO2 induce acidity will not be
uniform is that chemical changes in seawater is highly affect by the physical factors of
the planets meteorological condition and oceans geographical location.
For
example,inth study of Collins et al. (2010) weak tropical easterly trade winds in the

Pacific causes decreased upwelling, flattened thermocline, and high sea-surface
temperature warming rates near the equator. Thus resulting to spatial variability,
frequency and severity of bleaching phenomena (van Hooidonk et al., 2013).
The Effect of Sea Water Temperature Anomalies on Bleaching Occurrence
The regression analysis results showing Table 7 and 8 as well as Figure 3 below,
deduced the independent effect of seawater temperature anomalies on bleaching
occurrence among seawaters in selected regions in the world.
The results revealed that sea water temperature anomalies significantly predicted
independently on the bleaching occurrence for a long- time-period among sea waters
of selected regions in the world (  8.99, t  4.77, p  0.000) . The sea water
temperature anomalies also explained a significant proportion of variance in the
bleaching occurrence in the sea waters among selected regions in the world (
r 2  43.13%, F1,30  22.75, p  0.000 ). That is, for every unit increase in sea

water temperature anomalies, a rise by approximately 8.99 units on bleaching
occurrence is expected to occur.
Table 7: Analysis of Variance results showing the independent effect
of sea water temperature anomalies on bleaching occurrence

20


Table 8: Coefficients depicting the independent effect
of sea water temperature anomalies on bleaching occurrence

Figure 3: Normality Test Results on Standardized Residuals of Bleaching Occurrence

The result validates of a previously crafted hypothesis on the direct effect of seasurface temperature increase on coral bleaching, that warmer water temperatures can
result to expelling of the algae (zooxanthellae) living in their tissues causing the coral
to turn completely white or bleached. the widespread of bleaching occurrences were

primarily attributed to the extreme warm sea-surface temperature in combination with
other environmental factors making it a critical variable to be considered in climate
change studies (Brown et al., 2002; Fitt et al., 2001). According to the study conducted
by Mcwilliams et al. (2005) the coral bleaching events correlates well with observed
global sea temperature rise and particularly thermal anomalies. this association is
clearly observed in bleaching occurrences in Caribbean basin in the 1980s and 1990s
increased logarithmically with SST anomalies. the coral cover decline associated with
bleaching acrossWestern Indian Ocean also coincide with climatic oscillation event
ythat is known to have raised both atmospheric and sea-surface temperature in that
period (Ateweberhan and McClanahan, 2010).

21


The Bleaching Severity Levels as Induced by Bleaching Occurrence among
Coral Reef Areas in Selected Regions in the World
Tables 9, 10 and Figure 4 shown below, reveals the regression model showing
the level of effects of bleaching occurrence on bleaching severity among seawaters in
selected regions in the world.
The results showed that bleaching occurrence significantly predicted the rise of
bleaching severity levels among sea waters of selected regions in the world
(  4.822, t  12.06, p  0.000) .The bleaching occurrence level in sea waters also
explained avery highly significant proportion of variance in the rise ofbleaching
severity levels in sea waters among selected regions in the world
(r 2  82.91%, F1,30  145.52, p  0.000) . The findings suggest that for a unit

increase in coral bleaching occurrence, a rise by approximately 0.4822 units on
bleaching severity level in sea waters among selected regions in the world will occur.
This is in accord with the result of the previous study which specify that high
frequency and intensity of bleaching occurrence expectedly reduce coral cover for

surviving corals has undergone stress and reduced vitality for growth and reproduction
(Hoegh-Guldberg, 1999).
Table 9: Analysis of Variance results depicting the level effect of bleaching occurrence
on bleaching severity among seawaters in selected regions in the world.

Table 10: Effect Coefficient of bleaching occurrence on bleaching severity among
seawaters in selected regions in the world

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5. Conclusion and Recommendation
This exploratory data analysis determine and characterize the effect of CO 2 and
sea -surface temperature anomalies on bleaching occurrence that it is both variable
can be used in predicting occurrence of coral bleaching. Separately CO2sea surface
temperature significantly predicted the bleaching occurrence for long- time-periods
among coral reef areas of selected regions in the world. But both does not reveal
simultaneous effects on the occurrence and severity of bleaching events. Projections
are useful exercises to help plan for future uncertainty in a dynamic system. This
have a bearing on the conservation management of coral reef areas of the planet.
Reducing other anthropogenic stressors to avoid compounding effects. So as with the
protection of the resilient species and coral reef areas for future source of coral
propagules for recovery.
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