Bio-indicator bacteria & environmental variables of the coastal zones: The example of the Güllük Bay, Aegean Sea, Turkey

Fecal indicator bacteria diversity and decay in an estuarine mangrove ecosystem of the Xuan Thuy National Park, Vietnam

Mangroves are complex and dynamic ecosystems that are highly dependent on diverse microbial activities. In this study, laboratory experiments and field studies for fecal indicator bacteria (FIB) decay rates are carried out for the first time in the Xuan Thuy Mangrove Forest Reserve of Vietnam. Results show that there are significant differences in bacterial diversity in the water of mangrove areas that have been deforested compared to those which have been planted. The highest mean total coliform (TC) and Escherichia coli (EC) values were found in the natural mangroves (3,807±2,922 and 964±1133 CFU 100 ml^-1, respectively). The results indicated that the source of contamination and seasonal changes affect the abundance of fecal bacteria. These results were exceeding by far the safety guidelines for individual, non-commercial water supplies in most of the samples. In the planted mangrove sampling sites, the highest mean Fecal streptococci (FS) values of 1,520±1,652 CFU 100 ml^-1 were found. Microbial die-off rates were calculated over 5 days, and observed to be systematically higher for TC than for EC.

Microbes as Bioindicators for Contamination of Shatt Al-Arab Sediments in Basrah, Iraq

Shatt Al-Arab River in Basrah, Iraq represents an important source of fresh water so the current study aimed to determine the extent of pollution of the Shatt al-Arab River with some heavy metals and hydrocarbons by measuring their concentrations in sediment samples collected from different stations along the river, as well as the adoption of biomarkers represented by bacteria and fungi in determining the extents of such pollution. The results indicate that the river is contaminated with the following metals:: Ni, Cr, Zn, Pb, Cu and Cd. The total mean concentrations of heavy metals in the exchangeable part were high with 55.23, 53.76, 40.52, 33.84, 32.70 and 14.88 µg/g, respectively. The results also indicated a high concentration of hydrocarbons where the total mean was 28.52 µg/g. Bacteria and fungi represent vital indicators of heavy metals and hydrocarbons pollution in the environment. Different types of bacteria (Sphingomonas paucimobilis, Bacillus subtilis, Pseudomonas aeruginosa, Streptococcus thoraltensis, Staphylococcus lentus, Leuconostoc cremoris and Leuconostoc mesenteroides) and fungi (Aspergillus terreus, Aspergillus fumigatus, Aspergillus niger, Curvularia sp., Eurotium cristatus, Talaromyces flavus, Mucor sp., Rhizopus sp., Trichoderma sp., Dichotomomyces cejpii, and Penicillium spp.) have been isolated from the same sediment. Isolated of specific genera from bacteria and fungi like these isolated in the present study from the sediment of all studied stations reinforces the rest of the results recorded during the current study and confirms the pollution of the river with the studied pollutants.

The impact of fish farming on the water column and marine sediments in three coastal regions from eastern Aegean coast

The impacts of mariculture activities in the water and sediments were comprehensively evaluated for the first time in this study. Lower dissolved oxygen was detected near the cages during summer due to aquacultural activities and bacterial degradation of organic compounds. However, DO levels were not below the 5 mg L^-1 limit recommended for aquatic growth, survival and metabolic processes. Different eutrophication assessment methods showed that Güllük Bay, where intensive aquaculture activities occurred, was characterized by poor status. Assessment of different eutrophication tools for Akköy and Ildır Bay indicated that water quality status was not similar to each other. The most noticeable effect of aquaculture activities is the sedimentation of faeces and uneaten food under the cages. Nutrients in the water indicated gradual decrease with distance from the cages. Comparison of total phosphorus in sediments showed that the most affected area is Güllük Bay owing to cumulative impact of aquaculture. The higher total organic carbon (TOC) in sediments was measured near and under the cages. TOC was a useful indicator to show benthic health, less than 10 mg g^-1 corresponded to low risk deteriorations for all aquaculture sites. Sediment monitoring studies should be carried out to provide sustainable use of the aquaculture areas.

Long-Term Monitoring of Noxious Bacteria for Construction of Assurance Management System of Water Resources in Natural Status of the Republic of Korea

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.

Occurrence of four waterborne viruses at five typical raw water resources in the Republic of Korea during August 2013 to February 2019

Waterborne diseases have critical public health issues and socioeconomic relevancy worldwide. Various viral pathogens are ordinarily associated with waterborne diseases. Six-year-surveillance (a total of 20 times) of norovirus, hepatitis A virus, group C rotavirus, and enterovirus was conducted at five raw water sampling sites including two lakes (Lakes Soyang and Juam), Hyundo region of Geum River in Daejeon City, and Guui region of Han River in Seoul Metropolitan City and Moolgeum region of Nakdong River in Gimhae City which are located near two water intake plants. In this study, we routinely investigated virus contamination in water samples through reverse transcription polymerase chain reaction (RT-PCR) and integrated cell culture RT-PCR with high sensitivity and specificity. A total 100 samples were tested. Most of the targeted viruses were found in 32% of the samples and at least one of the indicator bacteria was detected in 65% of these occurrences. Among all the detected viruses, enterovirus was the most prevalent with a detection frequency of 12% and 2.71 MPN/10 L on average, while hepatitis A virus was the least prevalent with a detection frequency of 4%. Nearly all of the analyzed viruses (except for group C rotavirus) were present in samples from Han River (the Guui region), Geum River (the Hyundo region), Lake Juam, and Nakdong River (the Moolgeum region), while group C rotavirus was detected in those from the Guui region. During the six-year sampling period, the targeted waterborne viruses in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five representative Korean water environments makes it necessary to establish the chemical and biological analysis systems for waterborne viruses and sophisticated management systems.

Antibiotic and Heavy Metal Resistant Bacteria Isolated from Aegean Sea Water and Sediment in Güllük Bay, Turkey : Quantifying the resistance of identified bacteria species with potential for environmental remediation applications

Heavy metal and antibiotic-resistant bacteria have potential for environmental bioremediation applications. Resistant bacteria were investigated in sediment and seawater samples taken from the Aegean Sea, Turkey, between 2011 and 2013. Bioindicator bacteria in seawater samples were tested using the membrane filtration technique. The spread plate technique and VITEK® 2 Compact 30 micro identification system were used for heterotrophic aerobic bacteria in the samples. The minimum inhibition concentration method was used for heavy metal-resistant bacteria. Antibiotic-resistant bacteria were tested using the disk diffusion method. All bacteria isolated from sediment samples showed 100% resistance to rifampicin, sulfonamide, tetracycline and ampicillin. 98% of isolates were resistant against nitrofurantoin and oxytetracycline. Higher antibiotic and heavy metal resistance was recorded in bacteria isolated from sediment than seawater samples. The highest levels of bacterial metal resistance were recorded against copper (58.3%), zinc (33.8%), lead (32.1%), chromium (31%) and iron (25.2%). The results show that antibiotic and heavy metal resistance in bacteria from sediment and seawater can be observed as responses to environmental influences including pollution in marine areas.

Beetles as Model Organisms in Physiological, Biomedical and Environmental Studies - A Review

Model organisms are often used in biological, medical and environmental research. Among insects, Drosophila melanogaster, Galleria mellonella, Apis mellifera, Bombyx mori, Periplaneta americana, and Locusta migratoria are often used. However, new model organisms still appear. In recent years, an increasing number of insect species has been suggested as model organisms in life sciences research due to their worldwide distribution and environmental significance, the possibility of extrapolating research studies to vertebrates and the relatively low cost of rearing. Beetles are the largest insect order, with their representative - Tribolium castaneum - being the first species with a completely sequenced genome, and seem to be emerging as new potential candidates for model organisms in various studies. Apart from T. castaneum, additional species representing various Coleoptera families, such as Nicrophorus vespilloides, Leptinotarsa decemlineata, Coccinella septempunctata, Poecilus cupreus, Tenebrio molitor and many others, have been used. They are increasingly often included in two major research aspects: biomedical and environmental studies. Biomedical studies focus mainly on unraveling mechanisms of basic life processes, such as feeding, neurotransmission or activity of the immune system, as well as on elucidating the mechanism of different diseases (neurodegenerative, cardiovascular, metabolic, or immunological) using beetles as models. Furthermore, pharmacological bioassays for testing novel biologically active substances in beetles have also been developed. It should be emphasized that beetles are a source of compounds with potential antimicrobial and anticancer activity. Environmental-based studies focus mainly on the development and testing of new potential pesticides of both chemical and natural origin. Additionally, beetles are used as food or for their valuable supplements. Different beetle families are also used as bioindicators. Another important research area using beetles as models is behavioral ecology studies, for instance, parental care. In this paper, we review the current knowledge regarding beetles as model organisms and their practical application in various fields of life science.

Assessing the seawater quality of a coastal city using fecal indicators and environmental variables (eastern Aegean Sea)

The presence of fecal bacteria in seawater is one of the most important bio-indicator parameters of fecal pollution. In this study, the Bay of İzmir (in the eastern Aegean Sea), which is a critical area because of its relationship with marine transportation and industrial and commercial activities, was evaluated for its microbiological and physicochemical parameters through a monitoring program. The data were obtained from seasonally assembled surface seawater samples from 2015 to 2017 at 23 sampling stations. Bacteriological investigations were performed by membrane filtration technique. During the monitoring period, for stations at the inner and middle-outer part, it was found that the inner part is exposed to more number of fecal coliforms (8.8×10²cfu/100mL) and fecal streptococci (1.1×10³cfu/100mL). The monitoring analysis performed in this study showed that there was negative correlation between physicochemical parameters and the level of fecal bacteria, but no significance was recorded by the Pearson correlation test. Fecal contamination parameters should be routinely monitored for improving the environmental conditions of coastal cities.