Southwestern Area Research Articles

KEY ROLE OF FOSSIL SEAWATER IN NEOGENE SEDIMENTARY ROCKS FOR LANDSLIDE OCCURRENCES IN THE NORTHERN PART OF CENTRAL JAPAN

The south-western area of Niigata Prefecture has the highest landslide densities in Japan. Saline groundwater emerges from several landslides in this area and is an influential factor in the occurrence of these landslides. The geochemical approaches to groundwaters and application of the electromagnetic surveys for landslide slopes revealed the hydrogeological structure of the large-scale landslides which was located on the outlet of saline waters from deep reservoirs and landslide-prone area where wide zonal distributions of saline water at depths of more than 50–100 m and fresh water at depths of shallower than 50–100 m. It is most likely that the saline groundwater behavior emerging in large-scale landslides is controlled by injections of the geo-pressured saline waters from deep reservoirs. The injection of the geo-pressured waters into the landslide mass likely results in excess pore pressure, which is a possible cause of landslide occurrence. On the other hand, the shallow fresh groundwater is inferred to be meteoric water of origin that replaced the saline groundwater, which likely weakened the shear strength of bedrocks, resulting in landslides. Thus, pore saline water plays an important key role in the occurrence of landslides, both large-scale landslides with low frequency and common landslides.

Plant growth promoting activities of Pseudomonas sp. and Enterobacter sp. isolated from the rhizosphere of Vachellia gummifera in Morocco.

The Moroccan endemic Vachellia gummifera grows wild under extreme desert conditions. This plant could be used as an alternative fodder for goats, and camels, in order to protect the Argan forests against overgrazing in Central and Southwestern Moroccan semiarid areas. With the aim to improve the V. gummifera population's density in semiarid areas, we proposed its inoculation with performing plant growth-promoting bacteria. Hence, 500 bacteria were isolated from the plant rhizosphere. From these, 291 isolates were retained for plant growth-promoting (PGP) activities assessment. A total of 44 isolates showed the best phosphates solubilization potential, as well as siderophore and auxin production. The combination of REP-PCR (repetitive extragenic palindromic-polymerase chain reaction) fingerprinting, PGP activities, and phenotypic properties, allowed the selection of three strains for the inoculation experiments. The three selected strains' 16S rRNA sequencing showed that they are members of the Enterobacter and Pseudomonas genera. The inoculation with three strains had diverse effects on V. gummifera growth parameters. All single and combined inoculations improved the plant shoot weight by more than 200%, and the root length by up to 139%, while some combinations further improved protein and chlorophyll content, thereby improving the plant's forage value. The three selected strains constitute an effective inoculum for use in the arid and semiarid zones of southern Morocco.

A Study on Spatiotemporal Changes of Ecological Vulnerability in Yunnan Province Based on Interpretation of Remote Sensing Images

The inherent ecological environment of mountainous regions is highly fragile, and the degree of sustainable development is low. There has not yet been a multi-phase ecological vulnerability evaluation (EVE) study based on remote sensing (RS) and GIS for mountainous provinces, for which there is an urgent need to establish a system that is appropriate, practicable and easily operated and applied. In this study, an integrated “RS and GIS + multi-phase land use/cover change (LUCC) + practically quantitative theory and methods of EVE” approach was adopted for analysis based on the interpretation results of five phases of the land use/land cover (LULC) RS images of Yunnan, with 129 counties being considered as the evaluation units. The organic combination of quantitative multi-index comprehensive evaluation (QMCE) and qualitative comprehensive analysis (QCA) methods was adopted to perform quantitative calculations of a system of county-level evaluation indicators which includes “innate” natural ecological vulnerability (INEV), land use ecological vulnerability (LUEV) and land cover ecological vulnerability (LCEV); the degree of ecological vulnerability (DEV) was assessed for the 129 counties within the province during the five study phases (1980, 1990, 2000, 2010 and 2020). The spatiotemporal variation characteristics and laws of DEV from 1980 to 2020 in the whole province and 129 counties were revealed, aiming to provide a basis for meeting the SDGs for mountainous provinces. The results are as follows: (1) Overall, INEV is high because of the high mountains and steep slopes, and the entire province is classified as “highly vulnerable” on average. In terms of counties, more than 79.07% are classified as “moderately vulnerable”, “highly vulnerable” and “very highly vulnerable”. (2) The degree of LUEV and LCEV caused by acquired human socioeconomic activities was higher in 1980. However, after a series of ecological measures in the past 40 years, the values of DEVLU and DEVLC in the whole province and counties in 2020 have decreased to different degrees. Accordingly, the degree of overall ecological vulnerability of Yunnan province and counties decreased significantly from 1980 to 2020. The basic law of change is that the number of counties with high DEV decreases significantly, while the number of counties with low DEV increases significantly. (3) The regional difference in the DEV of Yunnan province is large. In general, the degree of ecological vulnerability is lower in the southern, southwestern, western and central areas of Yunnan and higher in the northwest high mountain canyon, northeast mountain areas and east and southeast karst areas. (4) Overall, the DEV in Yunnan province is currently still high. There is an urgent need to enhance the construction of ecological civilization across the whole province and take effective measures to protect the ecological environment according to local conditions, so as to steadily reduce the DEV.

Assessing Lantana camara spatial distribution in response to rainfall and temperature variations in Inkomati catchment in Mpumalanga

Lantana camara is an invasive plant affecting global natural ecosystems, including South African ecosystems. Preceding studies have focused on accurately identifying and mapping its spread, without understanding its adaptability to different environments. The aim of this study was to map and distinguish L. camara from different Land Use Land Cover (LULC) types, using Google Earth Engine (GEE) platform, Sentinel 2 satellite data and Random Forest algorithm in Inkomati Catchment, Mpumalanga. The study also modelled the influence of rainfall and temperature on the L. camara, and predicted its future distribution, using the Maximum Entropy (Maxent) Species Distribution Modelling (SDM) approach. Overall, the accuracy of the identification of L. camara was 90.27%, with a user's and producer's accuracy of 80% and 89%, respectively. L. camara was detected mostly within the eastern, south-eastern and south-western areas of the Komati sub-catchment and in the north-eastern parts, of the Nwanedzi River sub-catchment in the Kruger National Park. In comparison to other LULC classes, the prevalence of L. camara was found to be sparse and heterogeneous across the catchment. L. camara spatial distribution was significantly influenced by the mean temperature of the coldest and driest quarters and the rainfall of the wettest quarter. The current and future climatic scenario models built using the selected bioclimatic variables, yielded high species predictive accuracies of 0.937 and 0.932, respectively. These findings are useful in assessing landscapes vulnerable to L. camara invasions, the potential of remote sensing, and species distribution modelling towards the management of species invasion.

Partial least-squares regression for soil salinity mapping in Bangladesh

Estimating the salinity of the soil along the coast of south-western Bangladesh is the focus of this study. Thirteen soil salinity indicators were computed using the Landsat OLI images, and 241 soil salinity samples were gathered from secondary sources. In this research, partial least-squares regression was used to estimate soil salinity. Soil salinity zones were then divided into five classes based on Jenks natural breaks. There is a strong relationship between soil salinity and several indices, including B2 (Blue band), B5 (Near-Infrared band), SI_1 (Salinity index 1), and SI_2 (Salinity index 2). The correlation between B2 and soil salinity is particularly high, hovering around 0.92. The majority of other factors, however, have a negative or barely positive correlation of −0.260 to 0.032. Very high and high levels of salinity are estimated to cover 29.02% and 13.45% of the study area, respectively, based on the soil salinity map. Finally, cross-validation has been used to see how well the model works to predict soil salinity for a specified weight. Iteration has been done three times in order to assess the model's performance on various subsets of data and produce a more accurate prediction. In the third iteration, PRESS, RSS, and Q2cum values were 1.844826, 3.354687, and 0.9705131, correspondingly, which indicates a higher predictive accuracy. The findings of the study will be useful as a tool for policymakers in the south-western coastal area of Bangladesh who are responsible for integrated coastal zone management.

Serological evidence of Rift Valley fever viral infection among camels imported into Southern Algeria

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis caused by the Rift Valley fever virus (RVFV). The present work aims to investigate the epidemiological status and identify the risk factors associated with RVFV infection in dromedary camels (Camelus dromedarius) from southern Algeria. A total of 269 sera of apparently healthy camels was collected and tested using a competitive Enzyme-Linked Immunosorbent Assay (ELISA). Overall, 72 camels (26.7 %, 95 % CI: 21.4–32) were seropositive to RVFV. IgG antibodies were found to be most prevalent in camels from south-western areas, particularly in Tindouf wilaya (52.38 %, p < 0.0001), and in camels introduced from bordering Sahelian countries (35.8 %) (OR = 8.75, 95 %CI: 2.14–35.81). No anti-RVFV antibodies were detected in sera collected from local camels (0 %). Adult (5–10 years) and aged (>10 years) camels have a significantly higher risk of being infected by RVFV (OR = 2.15; 95 %CI = 1.21–3.81, OR = 2.05; 95 %CI = 1.03–4.11, respectively). This report indicated that dromedaries imported to the south-western areas are exposed to RVFV and may contribute to its spread in Algerian territories.

Potential impacts of climate change on the distribution of echinoderms in the Yellow Sea and East China Sea

To detect potential impacts of climate change on the distribution of common echinoderm species in the Yellow Sea (YS) and East China Sea (ECS), species distribution models (SDMs) were applied. Ensemble SDMs were constructed and were in good model performance for six of the eight selected common echinoderm species. Under future climate scenarios, the brittle stars Ophiopholis mirabilis, Amphioplus depressus and the sea cucumber Protankyra bidentata were projected to expand in the southwestern areas of the YS, the ECS, and the coastal areas of the YS and ECS, respectively; the brittle stars Stegophiura sladeni, Amphiura digitula and Amphiura vadicola will likely contract their ranges in the south distribution areas and expand in the north, showing a northward movement trend. Temperature was the most important environmental variable influencing the distribution of the latter three echinoderms. Our findings will improve our understanding of the impacts of climate change on marine species distributions.

CARTOGRAPHY FOR SUSTAINABLE TOURISM OF CULTURAL TOURISM ATTRACTIONS AROUND SAWASWAREESRIMARAM TEMPLE, DUSIT DISTRICT, BANGKOK

This research was conducted to develop tourist attractions, especially cultural tourism attractions in the community area around Sawaswareesrimaram Temple, Dusit district, Bangkok. The objective is to develop spatial potential by applying geographic information systems for mapping local communities in location determination, planning, and spatial development. The methodology was obtained from field surveys by recording the coordinates of cultural tourist attractions with Global Positioning System (GPS) and using geographic information systems for mapping. It also adopts the principle of analyzing the density of attractions with Kernel Density. The results reveal that there were 4 types of cultural attractions in Dusit District: Institution, Palace and Museum, Religious places, and Restaurant – Street food. The distribution pattern of most cultural attractions was in the south-western area of the study area, with the density of cultural attractions greater than 1 km2. Cultural attractions in the form of Restaurant and Street food were found to have a very high density in the Sri Yan area, showing a level greater than 1 km2 along Sam Sen road and Nakhon Chai Si road. As for Thewet district, there was a density level of 0.2-0.6 km2, which were all distributions of street food, dense at the intersection of roads. In summary, the mapping can provide local people with a tool for planning cultural sites, to enhance their livelihoods, love and cherish their homeland, and increase their income, leading to future tourism developments.

Environmental Conditions Affect Striped Red Mullet (Mullus surmuletus) Artisanal Fisheries

The influence of environmental variables (oceanographic and climatic) on the catch rates of striped red mullet (Mullus surmuletus) by artisanal fishery was investigated using different time series models (Dynamic Factorial Analyses; Min-Max Factorial Analyses and Generalized Least Square models). Climatic and oceanographic survey data were collected at different areas of the Portuguese coast (Northwestern, Southwestern and South-Algarve) with distinct oceanographic regimes. Time series analyses reveal an effect of fishing effort in catch rates in Southwestern areas. Variability in M. surmuletus catch rates was associated to regional environmental multi-controls. Upwelling and westerly winds were the main drivers of catch rates variability across the three areas but the type of relationship varied among them. A consistent relationship between catch rates and environment factors was identified during the peak period of seasonal recruitment (spring to summer) in Southwest and South-Algarve coast, with Upwelling-summer and Sea surface temperature-spring affecting short term (lag 2 years) catch rates. In South-Algarve the increase in SST in summer, during peak of spawning, was correlated with the catch rate increase with a lag of two years. Environmental effect on catch rates reveals that fisheries management needs to accommodate the regional effect of environment variables on species biology to better define future assessment plans (catch limits).

Preliminary Population Exposure to Indoor Radon and Thoron in Dhaka City, Bangladesh

Radon, an element of natural radiation, is considered one of the leading causes of lung cancer worldwide. In Bangladesh, radon has been clarified as a foremost source of radiation exposure. Potential natural-radiation-induced elevated cancer risks were estimated in Bangladesh previously for the population. In this survey, as a very preliminary study in the country, comparative indoor radon (222Rn, Rn) and thoron (220Rn, Tn) concentration/population exposure was determined for the multistoried dwellings of south-western areas of Dhaka city. RADUET was used to assess annual Rn and Tn concentrations in determining the primary inhalation dose for the population. The annual effective dose of Rn and Tn was evaluated in this study for dwellings at 0.3 mSvy−1, constituting a Tn dose contribution of an average of 40% with a dwelling-based wide range of 10–96%. Thus, Tn should not be neglected for Bangladesh while estimating radiological inhalation dose from the indoor environment. Again, the equilibrium factors, F of Rn and Tn, were determined by short-term measurement at averages of 0.6 and 0.02, respectively. Furthermore, using questionnaire estimation by principal component analysis, PCA following the dwelling characteristics, human lifestyles, and estimated long-term indoor Rn and Tn concentrations, this paper discussed indoor atmospheric/Rn factors for the investigated multistoried dwellings in Dhaka city.

Extraction of Rocky Desertification Information in the Karst Area Based on the Red-NIR-SWIR Spectral Feature Space

The complex topography, severe surface fragmentation and landscape heterogeneity of the karst region of southwest China make it extremely difficult to extract information on rocky desertification in the region. In order to overcome the disadvantages of the surface parameter-based feature space approach, which is difficult to construct and apply, this study uses the reflectance of Landsat 8 Operational Land Imager (OLI) in the red (Red), near-infrared (NIR) and shortwave infrared (SWIR) bands as the feature variables, and establishes a two-dimensional SWIR-NIR, Red-NIR and SWIR-Red reflectance spectral feature space. The three models of perpendicular rocky desertification index 1 (PRDI1), perpendicular rocky desertification index 2 (PRDI2) and perpendicular rocky desertification index 3 (PRDI3) were also constructed based on the variation of the degree of rocky desertification in each spectral feature space. The accuracy of the rocky desertification extracted by these three index models was verified and compared with the karst rocky desertification index (KRDI) and rocky desertification difference index (RSDDI), which are constructed based on the surface parameter feature space. The results show that: (1) The waveband reflectance-based feature space model provides a new method for large-scale rocky desertification information extraction, characterized by easy data acquisition, simple index calculation and good stability, and is conducive to the monitoring and quantitative analysis of rocky desertification in karst areas. (2) The overall accuracy and Kappa coefficient of PRDI1 are 0.829 and 0.784, respectively, both higher than other index models, showing the best applicability, accuracy and effectiveness in rocky desertification information extraction. (3) According to the results extracted from PRDI1, the total area of rocky desertification in Huaxi District of Guizhou province is 320.44 km2, with the more serious grades of rocky desertification, such as severe and moderate, mainly distributed in the southwestern, western and southeastern areas of Huaxi District. This study provides important information on the total area and spatial distribution of different degrees of rocky desertification in the study area, and these results can be used to support the local government’s ecological and environmental management decisions. The method proposed in this study is a scientific and necessary complement to the characteristic spatial methods based on different surface parameters, and can provide important methodological support for the rapid and efficient monitoring of karstic rocky desertification over large areas.

Spatiotemporal Variations and Determinants of Supply–Demand Balance of Ecosystem Service in Saihanba Region, China

Maintaining a supply–demand balance of ecosystem services (ES) is essential for enhancing the effectiveness of ecosystem restoration. However, inappropriate land use and reforestation practices can negatively impact this balance. In this study, the ES balance of the Saihanba region in China was quantified by integrating land use/cover change (LUCC) data, landscape metrics, and ES indicators. The relationship between ES balance and its driving factors was analyzed using spatial panel models. The spatiotemporal changes of landscape patterns from 2002 to 2020 were also explored. The results indicated that the overall ES supply capacity of the study region, especially in the southwestern area, increased during the research period. The ES balance and its determining factors exhibited significant spatial heterogeneity and spillover effects. Large–scale afforestation increased the local ES supply and provided economic benefits, but it also led to ecological issues, including declines in wetland area and landscape fragmentation. Our study emphasized the importance of considering the supply–demand balance in the planning and decision–making of ES, providing insight into multifunctional management and the sustainable development in the Saihanba area.

The Effects of Online Health Information-Seeking Behavior on Sexually Transmitted Disease in China: Infodemiology Study of the Internet Search Queries.

Sexually transmitted diseases (STDs) are a serious issue worldwide. With the popularity of the internet, online health information-seeking behavior (OHISB) has been widely adopted to improve health and prevent disease. This study aimed to investigate the short-term and long-term effects of different types of OHISBs on STDs, including syphilis, gonorrhea, and AIDS due to HIV, based on the Baidu index. Multisource big data were collected, including case numbers of STDs, search queries based on the Baidu index, provincial total population, male-female ratio, the proportion of the population older than 65 years, gross regional domestic product (GRDP), and health institution number data in 2011-2018 in mainland China. We categorized OHISBs into 4 types: concept, symptoms, treatment, and prevention. Before and after controlling for socioeconomic and medical conditions, we applied multiple linear regression to analyze associations between the Baidu search index (BSI) and Baidu search rate (BSR) and STD case numbers. In addition, we compared the effects of 4 types of OHISBs and performed time lag cross-correlation analyses to investigate the long-term effect of OHISB. The distributions of both STD case numbers and OHISBs presented variability. For case number, syphilis, and gonorrhea, cases were mainly distributed in southeastern and northwestern areas of China, while HIV/AIDS cases were mostly distributed in southwestern areas. For the search query, the eastern region had the highest BSI and BSR, while the western region had the lowest ones. For 4 types of OHISB for 3 diseases, the BSI was positively related to the case number, while the BSR was significantly negatively related to the case number (P<.05). Different categories of OHISB have different effects on STD case numbers. Searches for prevention tended to have a larger impact, while searches for treatment tended to have a smaller impact. Besides, due to the time lag effect, those impacts would increase over time. Our study validated the significant associations between 4 types of OHISBs and STD case numbers, and the impact of OHISBs on STDs became stronger over time. It may provide insights into how to use internet big data to better achieve disease surveillance and prevention goals.

A study of the effect of open biomass burning aerosol on rainfall event over Malaysia by using EOF analysis

Significant biomass burning aerosols resulted from biomass burning activities from Sumatra and Kalimantan Island transported to Malaysia every year from August to October by the southeast monsoon. These transboundary haze changes the precipitation pattern by aerosol interaction with radiation and cloud which affects the solar radiation budget and cloud condensation nuclei properties. In this work, empirical orthogonal function (EOF) was used to assess the effect of biomass burning aerosol on rainfall pattern over Malaysia from both a spatial and a temporal perspective. Over Peninsular Malaysia, regional rainfall activities tend to be suppressed by concentrated biomass burning aerosols and produce another heavy rain over the downwind areas after 30-60 days (60 days) under highly (less) populated condition. Similar precipitation pattern has been indicated over Sarawak and Sabah where biomass burning aerosols suppress rainfall in the southwestern area while leads to a more intensified rainfall event in the northeast area with 30-60 days (60 days) interval under highly (less) populated condition.

Using geochemical models to delineate the relationship between the Pleistocene aquifer groundwater and the oxidation ponds at El-Sadat city, Egypt

This study aims to assess the risk of the wastewater plume from the oxidation ponds contaminating the underneath shallow groundwater aquifer. The study area is an industrial city comprised of three main zones: industrial, populated, and agricultural. The study area is bordered on the eastern side by a wastewater pond and the Rosseta Nile river branch. The geochemical investigation is based on the determination of groundwater salinity, major ions, nitrogen compounds (NH4−, NO2−, NO3−), phosphate (PO43−), heavy metals, and the isotopic content (δ18O and δ2H) as well as the geochemical groundwater modeling. The results show most groundwater samples (50%) in the study area are freshwater, 31% are marginal saline water, and 18% are brackish. Higher nitrogen and PO43− compound concentrations are found in the shallow groundwater close to the oxidation ponds and populated zone. The δ18O and δ2H in the Quaternary groundwater is relatively depleted; they range from −2.1 to 2.3‰ and −7 to 21‰, respectively. The integrations of the geochemistry and isotopes show that the Pleistocene aquifer receives considerable recharge percent (14–56%) from the Rosseta Nile river branch and has been polluted due to the seepage from the oxidation ponds (seepage percent range: 0.6–3.6%). The results suggest that excessive fertilizer usage in the agricultural zone, seepage from oxidation ponds into the subsurface aquifer, and the anthropological effects of population size and industrial zones all contribute to the decline in groundwater quality. The highly vulnerable groundwater sites extend from the northeastern areas close to the oxidation ponds and the southwestern areas close to the industrial and populated zones.

Resolving when (and where) the Thylacine went extinct

Like the Dodo and Passenger Pigeon before it, the predatory marsupial Thylacine (Thylacinus cynocephalus), or ‘Tasmanian tiger’, has become an iconic symbol of anthropogenic extinction. The last captive animal died in 1936, but even today reports of the Thylacine's possible ongoing survival in remote regions of Tasmania are newsworthy and capture the public's imagination. Extirpated from mainland Australia in the mid-Holocene, the island of Tasmania became the species' final stronghold. Following European settlement in the 1800s, the Thylacine was relentlessly persecuted and pushed to the margins of its range, although many sightings were reported thereafter—even well beyond the 1930s. To gain a new depth of insight into the extinction of the Thylacine, we assembled an exhaustive database of 1237 observational records from Tasmania (from 1910 onwards), quantified their uncertainty, and charted the patterns these revealed. We also developed a new method to visualize the species' 20th-century spatio-temporal dynamics, to map potential post-bounty refugia and pinpoint the most-likely location of the final persisting subpopulation. A direct reading of the high-quality records (confirmed kills and captures, in combination with sightings by past Thylacine hunters and trappers, wildlife professionals and experienced bushmen) implies a most-likely extinction date within four decades following the last capture (i.e., 1940s to 1970s). However, uncertainty modelling of the entire sighting record, where each observation is assigned a probability and the whole dataset is then subject to a sensitivity analysis, suggests that extinction might have been as recent as the late 1980s to early 2000s, with a small chance of persistence in the remote south-western wilderness areas. Beyond the intrinsically fascinating problem of reconstructing the final fate of the Thylacine, the new spatio-temporal mapping of extirpation developed herein would also be useful for conservation prioritization and search efforts for other rare taxa of uncertain status.

3D Static Modeling and CO2 Static Storage Estimation of the Hydrocarbon-Depleted Charis Reservoir, Bredasdorp Basin, South Africa

An essential greenhouse gas effect mitigation technology is carbon capture, utilization and storage, with carbon dioxide (CO2) injection into underground geological formations as a core of carbon sequestration. Developing a robust 3D static model of the formation of interest for CO2 storage is paramount to deduce its facies changes and petrophysical properties. This study investigates a depleted oilfield reservoir within the Bredasdorp Basin, offshore South Africa. It is a sandstone reservoir with effective porosity mean of 13.92% and dominant permeability values of 100–560 mD (1 mD = 9.869233 × 10–16 m2). The petrophysical properties are facies controlled, as the southwestern area with siltstone and shale facies has reduced porosity and permeability. The volume of shale model shows that the reservoir is composed of clean sands, and water saturation is 10–90%, hence suitable for CO2 storage based on petrophysical characteristics. Static storage capacity of the reservoir as virgin aquifer and virgin oilfield estimates sequestration of 0.71 Mt (million tons) and 1.62 Mt of CO2, respectively. Sensitivity studies showed reservoir depletion at bubble point pressure increased storage capacity more than twice the depletion at initial reservoir pressure. Reservoir pressure below bubble point with the presence of gas cap also increased storage capacity markedly.

Spatial and temporal variation of physicochemical parameters of coastal waters in the southwestern region of Sri Lanka

Physicochemical parameters of coastal water in the southwestern area of Sri Lanka were studied from January to November 2016. Surface water samples from 15 selected locations were analysed according to standard methods. The ranges of the values recorded were; water temperature (WT) 26.5-33.9 ºC, pH 7.1-8.4, dissolved oxygen (DO) 4.4-7.4 mg L-1, salinity 14-38 ppt, electrical conductivity (EC) 27.1-53.8 mS cm-1, total suspended solids (TSS) 50.2-403.4 mg L-1, turbidity 1.2-64.9 NTU, nitrate nitrogen (NO3--N) 0.00-0.57mg L-1, nitrite nitrogen (NO2--N) 0.00-0.035mg L-1, ammoniacal nitrogen (NH4+-N) 0.00-1.72mg L-1, dissolved inorganic phosphorous (DIP) 0.00-0.65 mg L-1, biochemical oxygen demand (BOD) 0.1-11.6 mg L-1 and chemical oxygen demand (COD) 40-768 mg L-1. Results of Two-way ANOVA showed that there was a seasonal variability in parameters such as water temperature (p&lt;0.001), dissolved oxygen (p&lt;0.001), BOD (p&lt;0.001), COD (p&lt;0.001), nitrite nitrogen (p&lt;0.001), nitrate nitrogen (p&lt;0.001), dissolved inorganic phosphorous (p&lt;0.001), turbidity (p&lt;0.001), TSS (p&lt;0.001) and Chlorophyll a (p&lt;0.001). Spatial variation was identified in parameters, pH (p&lt;0.001), turbidity (p&lt;0.001), dissolved oxygen (p=0.004) and nitrite nitrogen (p&lt;0.001) whereas the interaction between time and location was significant in pH (p=0.005) and turbidity (p=0.007). However, EC, salinity and ammoniacal nitrogen were not significant by either of the factors of consideration. In conclusion, the physicochemical characteristics of water are highly variable over time and location due to both natural and human factors. Water quality near fish processing areas such as fishery harbours and fish markets relatively deteriorated in terms of pH, DO, turbidity and nitrite nitrogen compared to recreational beaches. It is recommended to regulate any discharges of sewage and industrial wastewater directly into the sea. A long-term coastal water quality monitoring programme is vitally important to comprehensively characterise the coastal segments for a long-term strategic plan for sustainable development.

A Study on fishes caught by bottom trawl at Jeju south-western sea area in the east china sea

A Study on fishes caught by bottom trawl at Jeju south-western sea area in the east china sea

Investigation on sea-bed waste by bottom trawl at the Jeju south-western area in the east china sea

Investigation on sea-bed waste by bottom trawl at the Jeju south-western area in the east china sea