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

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 15 Year Land UseLand 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 SarsCov2 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 MetalThiosemicarbazone Complexes Based on The QSPR Modeling Using MLR and ANN Methods 141 4 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 SarsCov2 Mpro? Quantum Chemical Insight Through QTAIM, NBO, FTIR, HOMOLUMO 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 sf981 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. Reuse 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

The International Conference on Natural Sciences and Environment 2020

December 27th, 2020 Dong Thap University, Vietnam

Assoc Prof., Dr Pham Minh Gian

Vice Rector of Dong Thap University, Vietnam

8h30 -

8h40 Orientation Speech

Assoc Prof., Dr Tran Van Tan

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

8h40 -

9h00

Presentation 1: New Research in

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

9h00 -

9h10 Discussion

9h00 -

9h20

Presentation 2: Heavy Metals in

Commercial Shrimps in Samar Sea

Presentation 3: Study on Sars-Cov-2

Inhibition Ability of Compounds in

Cymbopogon Citratus Oil Using

Quantum Chemical Calculations,

Simulation Techniques

Dr Bui Thi Phuong Thuy

Faculty of Basic Sciences, Van Lang University, Ho Chi Minh City, Vietnam

9h50 -

10h00 Discussion

Dr Bui Thi Phuong Thuy; Assoc Prof., Dr Tran Van Tan 10h00 -

10h20 Photo session and Coffee break

10h20 -

10h40

Presentation 4: Carbon Dioxide and

Sea Surface Temperature as Predictor

of Coral Reef Bleaching Occurrence

and Severity Levels

Dr Diana Shane A Balindo

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

Presentation 5: Monitoring 15-Year

Land Use/Land Cover Change in The

Vietnamese Mekong Delta

MSc Nguyen Ho

Department of Land management, Faculty of Agriculture, Natural Resources and Environment, Dong Thap University, Vietnam

Investigations on The Molecular

Structure, Vibrational Spectroscopy,

AIM, NBO, MEP, and HOMO-LUMO

Analysis of Benzoic Acid Monomer

and Dimer Based on Density

Functional Theory

MSc Truong Tan Trung

Institute of Research and Applied Technological Science (IRATS), Dong Nai Technology University, Vietnam

11h40 -

11h50 Discussion

MSc Truong Tan Trung;

Assoc Prof., Dr Tran Van Tan 11h50 Wrap-up and Closing

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

15-Year 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

Meneses-Adorador, and Jiro A Adorador Spatial Distribution of Threatened

Species‟ Mother Trees in Selected Forests over Limestone in Samar

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

141

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

HOMO-LUMO 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

L-asparaginase 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

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: ariel.mabansag@ssu.edu.ph

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 Two- way 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

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

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 &

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

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

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

Table 2 Average heavy metal concentration according to the site

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

** 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

Table 4 Mean difference of cadmium concentration in terms of location

(I) Location (J) Location

Mean Difference (I-J)

** 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

References

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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: Dianashane.balindo@ssu.edu.ph

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 CO 2 ) 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 CO 2 , 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, CO 2 , Seawater, Temperature

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 Hoegh-Guldberg, 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

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

(https://www.ncdc.noaa.gov/cag/global/time-series/globe/ocean) 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

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 periods varies directly with the four levels of bleaching severity categories The model below depicts the weight contributions of various types of bleaching severity levels

time-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

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

(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 CO 2 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 CO 2 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

Effects of CO 2 and Sea Water Temperature Anomalies on Bleaching Occurrence

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 CO 2 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

) 000 0 000 4 0765

.

0

(  t  p 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 (

2,29 25 04 0 000 F

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

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 (

1,30 22 75 0 000 F

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

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 surface temperature increase on coral bleaching, that warmer water temperatures can result to expelling of the algae (zooxanthellae) living in their tissues causing the coral

sea-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)

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

) 000 0 06 12 822

.

4

(  t p .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

1,30 145 52 0 000 ) F

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

5 Conclusion and Recommendation

This exploratory data analysis determine and characterize the effect of CO2 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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MONITORING 15-YEAR LAND USE/LAND COVER CHANGE

IN THE VIETNAMESE MEKONG DELTA

Nguyen Ho 1* , Phan Van Phu 2 , and Nguyen Thi Hong Diep 3

1 Department of Land management, Faculty of Agriculture, Natural Resources and Environment, Dong Thap University

2 Faculty of Geography, Ho Chi Minh city University of Pedagogy

3

Department of Land resource, College of Environment and Natural resource,

Can Tho University

*Correspondence: nguyenho@dthu.edu.vn

Abstract

Although land use/land cover (LULC) information plays a critical role in the maintenance of living standards with a balance among environment, development and sustainability, it remains little comprehensive understanding in the Vietnamese Mekong Delta (VMD) In this study, a time-series approach is proposed to carefully analyse the 15 years‟ spatiotemporal changes of LULC in the VMD, employing the random forest algorithm, Landsat images, ancillary and empirical reference data Results show that agriculture has been the most dominant land, accounting for approximately half of the whole region during the fifteen years Surprisingly, these land types have undergone dramatic transformation with the proportion of the wetland area decreasing from about 16 % in 2005 to 5 % in 2019, whereas that of the aquaculture area has sharply increased from about 12 % to 19 % over the same period Meanwhile, there has been a marked increase in the area of perennial crops and built-up lands These results of LULC maps and change detection may be used to help in understanding the impact of past policies and the role of several factors such

as socio-economic trends and environmental changes in the VMD

Keywords: Land use/land cover changes; Mekong delta; Landsat images,

Agricultural expansion; Wetland change

1 Introduction

Coastal deltas are fundamental to human beings due to their numerous advantages such as a diversity of natural resources as well as ecosystem services, but they are also considered as fragile ecosystems (Kelletat et al., 2005; Moder et al., 2012) The socioeconomic development and agricultural intensification are altering the delta‘s ecosystems, followed by possible negative impacts on society and the environment The evidence of these adverse effects can be clearly seen in the Vietnamese Mekong Delta (VMD), which plays an important role in the agricultural and aquaculture production for the country Although the delta accounts for only 12 %

of Vietnam‘s natural land area, it supplies a great percentage of the nation‘s agricultural products, for example, approximately 50 % of rice for domestic use, up to

90 % of exported rice, 65 % of aquaculture, 70 % of fruits, and 60 % of exported fish (GSO, 2019) These processes are closely linked to the exploitation of natural resources, thus holding substantial implications for the delta‘s rural landscapes (Duong

et al., 2001; Kelletat et al., 2005)

While land use/land cover (LULC) information is widely adopted to support instrumental to sustainable development and policy decisions (Castella et al., 2007; Nguyen et al., 2020), its role is not sufficiently acknowledged in the environmental management in the VMD In fact, there are global and regional LULC products ranging from coarse to medium resolutions, which cover the whole region Well-

known examples of coarse resolution LULC maps are IGBP (Global Land Cover

Characterization, n.d.), UMD (UMD Global Land Cover Facility, n.d.)⁠, GLC 2000

(Global Land Cover 2000, n.d.)⁠ and GlobCover 2009 (GlobCover Land Cover Maps,

n.d.)⁠ However, such a coarse spatial resolution LULC is likely not to accurately reflect the complex agricultural landscape in the delta Another noteworthy point is that many studies have focused mainly on a particular LULC namely the characterization and quantification of rice crop (Kontgis et al., 2015; Phung et al., 2020), aquaculture and mangroves (Thu & Populus, 2007), having no or little information on the full dominant LULC characteristics A LULC with few classes has conducted for the whole VMD by (Liu et al., 2020)⁠, but they combined agriculture, orchards and perennial plants into a single class and there are missing important classes such as open water Hence, more up-to-date geospatial information about landscape changes of the entire delta is basic needs for a better understanding of changes at the earth‘s surface and the successful modelling and simulation of the potential impact of changed drivers

Recent developments in remote sensing and computer sciences have heightened the need for cost-effective and accurate LULC mapping approaches in the support of ground truth data, followed by the creation of numerous change-identification algorithms and image processing methods Among algorithms, new evidence suggests that the Random Forest algorithm is considered one of the best machine-learning classifiers for large-scale LULC mapping (Maxwell et al., 2018)⁠ Given the idea, we employ Random Forest theory to propose an estimate of LULC change based on empirical evidence extracting from onsite data and local knowledge

Therefore, the specific objectives of this study were: (1) to create the milestone accurate LULC maps (2005 and 2019) for the entire VMD using Random

two-Forest algorithm and (2) to shortly analyze the LULC change from 2005 to 2019 in the delta

2 Materials and Methods

2.1 Study area

The Vietnamese Mekong Delta (VMD) located between 8033‘ – 10055‘N and

104030‘ – 106050‘E, was formed by the alluvium deposition of the Mekong River The delta, known as the Nine Dragon (Cuu Long) river delta, is home of approximately 20 million inhabitants and described as a vast triangular plain of about 40,000 square kilometers, stretching from the border between Cambodia and Vietnam to the Vietnam‘s East Sea The VMD is administratively divided into 13 provinces, including Can Tho city that could be the center of the delta (Fig 1)

Figure 1 The location of Vietnam in the South East Asia (a);

the location of the study area in Vietnam (b), and three sub-regions

of the Mekong delta (c, source (Mekong Delta Plan, 2013))

The topography of the VMD is relatively flat, ranging from one to two meters above the sea level Climate is affected by the East-Asian seasonal monsoon and characterized by two seasons: a rainy season from May to November and a dry season from December to April Annual precipitation varies between 1,800 and 2,300 mm, concentrating mainly in the rainy season, while it is warm whole year with the annual average temperature being around 27 °C

LULC is diverse and dynamic in the VMD It was dominantly covered by various agricultural lands, wetlands, fruit trees, and mangroves In recent decades, the government has promoted agriculture and aquaculture production, causing a major conversion among LULC types (Mekong Delta Plan, 2013; Nguyen et al., 2020)

2.2 Data acquisition and processing

Landsat imagery was the main data collection as considering the detection comparable ability of this long-term study with other previously useful results The VMD is a very cloudy area so that it is impossible to collect single cloud-free images covering the full delta We, therefore, used multi-season images which could not only address the problems of missing data but also improve the accuracy of land cover classifications due to the presence of phenological vegetation conditions (Rodriguez-Galiano et al., 2012)⁠ For the year 2019, this study used Landsat 8 Operational Land Imager (OLI) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+); Landsat 7 ETM+ and Landsat 5 Thematic Mapper (TM) for the year 2005 These data were collected from the Earth Explorer (USGS)

change-Table 1 The useful information of Landsat bands used in this research

Data/sensor Band No Wave length

2.3 Classification scheme

Based on the local knowledge, expertise, and consideration of the previous studies about LULC of the delta (Binh et al., 2005; Boles et al., 2004; Son et al., 2013), an eight-category LULC classification scheme was designed, namely agriculture, aquaculture, perennial crops, wetland, upland forest, mangrove forest, built-up area, and open water (Table 2)

Table 2 Brief description of the land use/land cover categories

of the study area

LULC type Code Description

Agriculture AG Rice paddy, seasonal cropland

Wetland WL Melaleuca forests, seasonally inundated grasslands

Perennial crop PC Fruit trees, trees in the residential areas and other

perennial plants

Built-up area BA Residential areas, and barren lands

Aquaculture AQ Fish and shrimp ponds and other aquaculture farms

Open water OW Rivers, canals and reservoirs

Upland forest UF Natural/planting Forest located in the upland areas

Mangroves MA Mangrove forest in coastal areas

The detailed flowchart of this study was prepared as Fig 2 Random forest algorithm is an ensemble learning method that employs a large number of classifiers

or decision trees (Breiman, 2001)⁠ It is widely applied for classification and regression due to its outperformance and robustness of its rivals (Maxwell et al., 2018)⁠ After classification, all LULC maps had been filtered by 3 x 3 kernel majority filters to minimize the ―salt-and-pepper effect‖ before validating and performing change detection

Classification (Random Forest, 100 trees)

Classified images 1

data

Calculate Spectral indices

Figure 2 Detailed flowchart of LULC mapping creation

3 Results and discussion

Overcoming the challenges of dense cloudy contamination, a time-series forest-based method was proposed to produce three new eight-category LULC classification (2005 and 2019) in the VMD, using the high temporal frequency of Landsat images, spectral indices, and ancillary data The performance of remote-sensing-based mapping can be significantly improved with support of ground-truth data and ancillary data Also, onsite images, local knowledge and experts‘ advice supply useful insights into this land cover mapping, instead of using singly visual interpretation A number of previous studies on the LULC mapping of the VMD rely mainly on the visual interpretation of high spatial resolution satellite data such as Google Earth images for validating that may cause errors (McRoberts et al., 2018)⁠ For example, (Liu et al., 2020) created a series of 7 LULC maps of the VMD from 1979 to

random-2015 based on mainly visual interpretation of Google Earth images These results seem to be essential for a long-term analysis of land cover dynamics We, however, found serious errors in these products based on our results and field surveys That is, 1

km away from the coastal line, coconut and fruit trees were misclassified as mangrove

at a large scale

Among methods to generate LULC map, Random forest is popular due to its high accuracy in classification (Maxwell et al., 2018) However, these products use some scenes of Landsat, thus it has some no-data pixels In our study, a large number

of Landsat images have been used to create LULC maps Thus the phenomenon of data pixel is not occurring In addition, large amount of image might be contributed to the higher accuracy of our products

no-Figure 3 Inland LULC maps of the VMD for the years 2005 (A); and 2019 (B) 3.2 LULC change in the VMD

The LULC transformation of the VMD varied according to local sub-regional areas and land cover types For instance, agricultural areas converted rapidly into aquaculture land type in coastal areas characterized by brackish environment, whereas perennial crops increased considerably along the Tien and Hau rivers and in the North East of the VMD Nevertheless, agriculture remained the most popular LULC type in

the flood plain regions, for instance Plain of Reeds and Long Xuyen Quadrangle (Fig 3) These findings are in agreement with previous studies reporting a noticeable interrelation between LULC dynamics and changing in hydrological regimes across the entire VMD (Le et al., 2018)

In addition, the VMD has a diverse LULC category However, agriculture is still the dominant LULC type, covering nearly 50 % of the total delta although the area of agricultural land has relatively decreased in the last fifteen years Other significant change is the rapid loss of wetland (Fig 4) Over the last 15 years, approximately 70

% of wetland has lost in the VMD In the opposite direction, orchard/perennial crops and aquaculture increased about two times respectively at the same period (Fig 4)

Figure 4 Gain/loss of LULC types in the period 2005-2020: Wetland (Series 1), Agriculture (Series 2), Perennial crops (Series 3), Artificial surfaces (Series 4), Aquaculture (Series 5), Water body (Series 6, Upland forest (Series 7),

and Mangroves (Series 8)

5 Conclusion

In conclusion, the results of our study demonstrate that the Vietnamese Mekong Delta is a large area with diverse LULC patterns that exhibits significant changes since the beginning of the 21 century Using the random forest algorithm, Landsat images, ancillary and empirical reference data, this study overcomes the major challenges of extremely cloudy contamination to generate new eight-category LULC products with

an overall accuracy range around 90% in the years 2005 and 2019 The main findings are that (i) agriculture was the most dominant land; (ii) large parts of natural wetlands lost due to the conversion into agriculture, perennial crops and aquaculture; (iii) there has been a substantial increase in the area of built-up lands with sparse built-up areas

Gain/Loss of LULC types in the period 2005-2019

Series1 Series2 Series3 Series4 Series5 Series6 Series7 Series8

These findings somewhat are consistent with the official long-term visons and strategies for the sustainable development of the VMD adapting to climate change and sea level rise (Mekong Delta Plan, 2013) The main driving forces of changes are expected to be anthropogenic activities with a series of policy promulgations and the rapid population growth in the VMD This understanding of LULC change status might contribute to model future the evolution of LULC patterns, thereby providing policy makers with a better adjustment to future land use plans in the VMD

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PAYMENTS FOR COASTAL AND MARINE ECOSYSTEM SERVICES:

LESSONS FROM PREVIOUS EXPERIENCES

Lam Kim Nhung 1 , Hong Cam Ngan 1 , Nguyen Minh Hieu 2

1 Nam Can Tho University, Can Tho City, Vietnam

2 Center for Environmental and Natural Resource Information Technology

of Tra Vinh province

Abstract

Marine and coastal environments are increasingly being degraded and losing their ability to provide the fundamental services upon which human wellbeing depends The traditional approaches to halt the decline focus on regulation against destructive practices However, in many cases these approaches have failed to change unsustainable practices among coastal communities due to the improperly compensating these communities for lost revenues caused by conservation activities, as well as providing an inadequately incentive for them to actively participate in marine and coastal protection Payments for ecosystem services (PES) schemes is an economic incentive-based mechanism for sustainable resource management by providing systems for beneficiaries of ecosystem services pay to the stewards of ecosystem services, which is increasingly acknowledged as an alternative to failed regulatory mechanisms In Vietnam, PES has been implemented widely in the terrestrial realm but its application in coastal and marine environments has only recently emerged and remains embryonic The current article provides an overview of the experiences and lessons learned have been generated from attempts to develop PES in marine and coastal realm from around the world By reviewing the literature, we aim to identify prospects which need to be taken into account for the successful application of payments for coastal and marine ecosystem services for the case of Vietnam

Key words: Payments for Ecosystem Services (PES), Marine and coastal

environments, Marine Protected Areas (MPA), Vietnam

1 INTRODUCTION

Marine and coastal environments are increasingly being degraded at an alarming rate and losing their ability to provide the fundamental services upon which human wellbeing depends Various marine and coastal resource management tools in which the ecosystem services framework can be applied include integrated coastal zone management, ecosystem-based management, community-based coastal management, marine protected areas, marine spatial planning (Granek et al., 2010; Ritchie, 2011) The success of management strategies depends on many factors, but a common barrier

to achieving full effectiveness and wider adoption of these tools is the lack of adequate financing (Milne & Christie, 2005) Payment for ecosystem services (PES) has received much attention as one of the potential tools Essam Yassin Mohammed, 2012 suggests that adding PES to existing regulatory schemes can make them more effective

in protecting both environments and livelihoods In Vietnam, this market-based approach is already relatively widely used on forest ecosystems, but its application in coastal and marine environments remains embryonic (Nguyen Van Quynh Boi, 2017) This paper will introduce marine and coastal ecosystem services and their value, provide definitions of PES, analyze the applicability of PES design elements in coastal and marine settings in order to generate the experiences necessary for which PES may

be an effective policy and financing tool for marine conservation in Viet Nam

2 CONTENT

2.1 Marine protected areas in Vietnam

Vietnam‘s seashore stretches more than 3,260 kilometers with an area of over 1 million km2 with 114 river mouths, 48 bays, 12 lagoons, over 3000 islands Marine and coastal ecosystems are featured with typical ecology of the tropics, there is around 11,000 marine species inhabiting in 20 typical marine ecosystems It‘s involved 2,038 species of fish, 653 species of seaweeds; 657 species of zooplankton, phytoplankton with 537 species, 94 mangrove plant species, 225 species of shrimp etc (Le Duc To et al., 2003) The coastal marine ecosystems are high in productivity and biodiversity which supports millions of impoverished coastal communities, who rely on them for both food and livelihoods Phuong Anh, 2015 figures that Total Economic Value (TVE)

of Vietnam's coral ecosystem is estimated at about 100 million USD/year, of which 1

km2 of coral reefs can provide up to 10,000 USD of seafood, the finding also mentioned

1 km2 of mangroves in Mekong Delta provide about 450 kg of seafood Beyond commodities such as fish and aquatic plants, coastal and marine ecosystems also provide

a range of vital ecosystem services that support the lives and livelihoods of coastal communities and others For example, they recycle nutrients, regulate natural hazards and stabilize the coastline and prevents erosion from waves and storms etc

Although these services bring direct benefits to humans, contributes to the national sustainable development strategy, and protects the environment, coastal marine ecosystem has experienced fast-diminishing under the weight of pollution, land clearance, coastal development, overfishing, natural disasters and climate change (Tran Dinh Lan et al., 2020) Thus far, the country has designated some coastal and marine areas in the country as marine protected area System of marine protected area

is established at sea, islands, archipelagos or in coastal waters with the aim of protecting and conserving aquatic resources, protecting marine eco-environment, serve

the sustainable development of the fisheries sector and importantly contribute to the protection of marine eco-environment (Decision 742/QĐ-TTg; Law on fisheries 18/2017/QH14) Resolution 36/NQ-TW on sustainable development of Vietnam‘s ocean economy by 2030, with visions towards 2045 set the goals to be achieved by

2030 that is marine, coastal and island ecosystems will be properly managed and protected; marine and coastal parks and reserves will account for at least 6 percent of the natural area of the country‘s maritime zones

Table 1 List of coastal marine protected areas in Vietnam

No Name Province Planning

area (ha) Gradation Classification

Planning phase

1 Cat Ba Hai Phong 15,331.6 National

15,000 Natural

reserve

In the sea 2020

No Name Province Planning

area (ha) Gradation Classification

Planning phase

15 Con Dao Ba Ria –

2,881.47 Species and

habitat conservation

In the sea 2020

(Source: Decision No 45/QD-TTg; Decision 742/QĐ-TTg) Decision 742/QĐ-TTg approving the plan on the system of Vietnam's marine conservation zones through 2020 regulates that in the immediate future, investment capital for the establishment of marine conservation zones will be allocated mainly from the state budget After completing the establishment of several state-run marine conservation zones, it is necessary to study and adopt mechanisms and policies to diversify forms of investment, encourage and attract domestic and overseas investors, scientists and international organizations and promote the participation of coastal and island fishing communities in the development and sustainable management of marine conservation zones According to Decree 26/2019/ND-CP guidelines for implementation of the law on fisheries, organizations and individuals whose operation involves marine protected areas have obligation to pay costs incurred in connection with services to the MPA management unit, except for those in connection with investigation and scientific research

Although there were initially regulations, scheme aims to provide legal guidance for increasing revenues from beneficiaries of marine and coastal ecosystem services has not specifically mentioned which leads to the limitations on applying payments for coastal and marine ecosystem services in Viet Nam Since 2010, new marine protected areas have been established or are in the process of being established in Vietnam, most marine protected area managers cite tourism as the most promising source of sustainable financing but only a few marine protected areas (e.g., Nha Trang, Ha Long,

Cu Lao Cham, Con Dao) directly generate significant income from tourism or some other fees related to the utilization of resources natural resource to supplement available state budget financial resources Besides, a few localities (in Ben Tre, Nam Dinh, etc.) are building up green brands for the aquatic products grown with environmentally friendly techniques, the market price of these products includes part

of the cost to pay for protecting marine ecosystems (Nguyen Van Quynh Boi, 2017; Nguyen Van Cong et al., 2015) Thus far, most of marine protected areas have insufficient proactive funding to carry out essential management activities and the funds coming from governments are often earmarked, greatly limiting flexibility