Estimation of Holocene bedload sedimentation rate in a paleo-drowned river-valley (Middle Harbour, Sydney estuary, Australia)

Middle Harbour is a drowned-river valley located adjacent to the larger Sydney estuary, Australia. Extensive, high-resolution seismic data were correlated with borehole, land use, topographical, and geological data to calculate the mass of genetically different sediment deposits in Middle Harbour. The Harbour follows a well-defined drowned river-valley structure featuring small fluvial bedload delta deposits in the upper reaches of the embayments, a deep, central extensive mud basin overlying transgressive basal accumulations and a large flood-tide delta at the entrance. Deposits of an estimated 5,094 t of bedload, 21,143 t of suspended sediment and 5,947 t of transgressive basal material located in the estuary provided sedimentation rates of 0.68 t y-1, 1.29 t y-1, and 2.86 t y -1 respectively. These rates, determined from measured accumulations, were surprisingly low and substantially smaller than modelled rates. However, low sedimentation rates for suspended material may be due to fine sediment escaping over the top of the marine tidal delta, which effectively traps all bedload material from exiting the Harbour. Results of this study indicate that Holocene bedload sedimentation in Middle Harbour was slow and regular until a rapid increase after urbanisation commenced in the catchment. Most pre-Holocene material was eroded from Middle Harbour during the Last Glacial period with sediment currently present in the estuary having been deposited since sea-level recovery.

The Fate of Glyphosate in Soil and Water: A Review

The fate of glyphosate in soil and water is dependent on the properties of glyphosate and its envoronement. Behaviour of glyphosate in soil, sediment and water is strongly influenced the way by which it can be adsorbed by soils, sediments, and suspended material in water. The role of soil organic matter, clay mineral, and amorphous minerals on the adsorption of glyphosate depends primarily on the nature and properties of the soil itself and the properties of glyphosate. Environmental factors have some influence on sorption and degradation of glyphosate. Glyphosate is rapidly inactivated in soil, is in part due to adsorption. Some soil properties have been identified strongly influence adsorption of glyphosate, such as clay minerals, composition of cations in exchangeable site of clay and organic matter, unoccupied phosphate adsorption site, degree of humification, and soil pH. Adsorption limits the availability of glyposate for microbial degradation. The sorbed glyphosate is not directly available to microorganisms in soil. Evidence also suggests that not only a strongly sorbed compound such as paraquat but also weakly sorbed compounds such as flumetsulam and picloram can persist for long periods when they are sorbed by soil constituents. This suggests that the interaction between sorption and biodegradation should be considered in predicting the fate of pesticides in soils and sediments.

Impact of Freshwater Discharge on the Carbon Uptake Rate of Phytoplankton During Summer (January–February 2019) in Marian Cove, King George Island, Antarctica

Rapidly changing conditions in high-latitude coastal systems can significantly impact biogeochemical cycles because these systems are strongly influenced by freshwater discharged from melting glaciers and streams on land. Generally, Antarctic coastal areas are considered high-productivity areas in which phytoplankton growth prevails under various environmental conditions (e.g., oceanographic and meteorological conditions). This study provides carbon uptake rates of phytoplankton in Marian Cove during summer (January-February 2019). Daily depth-integrated carbon uptake varied greatly and averaged 0.8 g C m–2 day–1, with a maximum of 4.52 mg g C m–2 day–1 recorded on 14 January. Similarly, the observed biomass standing stocks were very high (up to 19.5 mg m–3 chlorophyll a) and were dominated by microphytoplankton (20–200 μm), representing 84% of total chlorophyll a (chl-a). The depth-integrated chl-a and carbon uptake decreased from outer to inner areas (close to the glacial front) in the cove. As the austral summer progressed, the freshening of the surface waters coincided with high water stability and suspended material and with low productivity when nanophytoplankton were present (2–20 μm; >60%). These findings suggest that both photosynthetically active radiation penetrating the water column and enhanced turbidity control light availability for phytoplankton, as well as their community compositions.

The waters transparency model of Lake Laut Tawar, Aceh, Indonesia

Lake Laut Tawar in Aceh Province, Indonesia is an important ecosystem that has several endemic biotas such as Rasbora tawarensis and Poropuntius bargensis. Eutrophication is a potential problem in Lake Laut Tawar. To evaluate the trophic state needed the value of water transparency. This study aims to formulate a model for estimating the transparency of Lake Laut Tawar waters. The dependent variable was water transparency, and the predictors variable was the chlorophyll-a concentration, total suspended solids, and total dissolved solids. Observations and sampling were conduct starting from October 2016 to September 2017. Data analysis was using simple regression, multiple regression, and one-way ANOVA. The result showed a decrease in waters transparency (SD) was caused by increased phytoplankton density (Chl-a), suspended material (TSS), and dissolved material (TDS). But the dissolved matter did not have a partial effect if the values of other variables are constant. The model to estimate the water transparency of Lake Laut Tawar is Log SD = 1.414 – 0.322 Log Chl-a – 0.406 Log TSS. The average values of water transparency did no differential between the seven observation stations. It is presumably because the waters of Lake Laut Tawar are easily mixed.

The genome of an apodid holothuroid (Chiridota heheva) provides insights into its adaptation to deep-sea reducing environment

Cold seeps and hydrothermal vents are deep-sea reducing environments that are characterized by a lack of oxygen, photosynthesis-derived nutrients and a high concentration of reducing chemicals. Apodida is an order of deep-sea echinoderms lacking tube feet and complex respiratory trees, which are commonly found in holothurians. Chiridota heheva Pawson & Vance, 2004 (Apodida: Chiridotidae) is one of the few echinoderms that resides in deep-sea reducing environments. Unlike most cold seep and hydrothermal vent-dwelling animals, C. heheva does not survive by maintaining an epi- or endosymbiotic relationship with chemosynthetic microorganisms. The species acquires nutrients by extracting organic components from sediment detritus and suspended material. Here, we report a high-quality genome of C. heheva as a genomic reference for echinoderm adaptation to reducing environments. Chiridota heheva likely colonized its current habitats in the early Miocene. The expansion of the aerolysin-like protein family in C. heheva compared with other echinoderms might be involved in the disintegration of microbes during digestion, which in turn facilitates the species' adaptation to cold seep environments. Moreover, several hypoxia-related genes were subject to positive selection in the genome of C. heheva, which contributes to their adaptation to hypoxic environments.

Screening and Quantification of Micro(Nano)Plastics and Plastic Additives in the Seawater of Mar Menor Lagoon

In this work a suspect-screening approach was employed to assess the polymers and plastic additives of micro(nano)plastics (NPL/MPLs) of size ranges from the nm range to 20 μm present in seawater from the top 5 cm of the Mar Menor lagoon during two sampling campaigns (summer and winter), as well of other potentially adsorbed compounds onto the plastic particles surfaces and suspended material. The identification of NPL/MPLs has been based on characteristic Kendrick Mass Defect analysis for each polymer type in mass spectra. The applied methodology allowed to identify NPLs/MPLs of polystyrene (PS), polyethylene (PE), polyisoprene (PI), polybutadiene (PBD), polypropylene (PP), polyamides (PA), polyvinylchloride (PVC), n-isopropylacrylamide (PNIPAm), and polydimethylsiloxanes. In addition, PS, PE, PI, PBD, PP, PA, and PVC were confirmed with standards, and the equivalent concentrations were quantified. The results of this study showed that most frequently found compounds were PP, PE, PA and PNIPAm, while the compound found at higher concentrations was by far PP reaching the 9,303 ± 366 ng/mL in one of the samples. A total number of 135 chemical compounds were tentatively identified, 74 of them plastic additives and compounds used in the polymers manufacture or coming from the polymer’s decomposition. In relation to plastic additives, the more frequently tentatively identified compounds were plasticizers such as phthalates group; stabilizers such as antioxidants (e.g., distearyl 3,3′-thiodipropionate, 2,5-di-tert-butylhydroquinone), and UV filters as benzotriazoles. Several flame retardants of the group of phosphates were as well detected. The other compounds tentatively identified in the samples were pharmaceuticals, pesticides, food additives, flavors and natural products that were attached onto the plastic particles and particulate matter from surrounding waters. In regards to the seasonal variation, during the summer a major number of compounds were tentatively detected, while de concentrations of polymers were slightly higher in winter. The spatial distribution showed higher contamination in the southern part of the coastal lagoon.

Phân bố hàm lượng chất rắn lở lửng (TSS) tỉnh An Giang sử dụng ảnh viễn thám sentinel 2A

Trầm tích lơ lửng (phù sa) đóng vai trò hết sức quan trọng trong việc cung cấp nguồn dinh dưỡng, có ý nghĩa rất lớn trong sản xuất nông nghiệp và cả hệ sinh thái vùng Đồng bằng sông Cửu long (ĐBSCL). Nghiên cứu đã sử dụng phương pháp hồi quy tương quan giữa giá trị chỉ số vật chất lơ lửng (Normalized Suspended Material Index) trên ảnh và lượng phù sa thực tế để thành lập bản đồ phân bố phân bố không gian hàm lượng tổng chất rắn lơ lửng trong nước mặt (phù sa). Kết quả xác định hệ số R2 trong các hàm hồi quy này đạt 0,868 cho đợt quan trắc ngày 18/10/2019. Kết quả xác định hàm lượng tổng chất rắn lơ lửng từ ảnh Sentinel 2A tỉnh An Giang có giá trị dao động trong khoảng từ 0-100mg/l. Hàm lượng tổng chất rắn lơ lửng tập trung chủ yếu trên các cánh đồng ngập nước, vùng thượng nguồn và cuối nguồn dọc theo tuyến sông Hậu thuộc tỉnh An Giang. Kết quả nghiên cứu cho thấy dữ liệu ảnh Sentinel 2 có khả năng hỗ trợ xây dựng bản đồ phân bố hàm lượng chất lơ lửng nước mặt cụ thể năm 2019 với độ tin cậy cao. Kết quả này là tiền đề cho các đề tài nghiên cứu có liên quan đến tăng giảm hàm lượng phù sa hay chất lượng phù sa vùng ĐBSCL đặc biệt là các vùng cửa sông tại Việt Nam.

Total Suspended Solid (TSS) Estimation in Lake Tempe, South Sulawesi Using Sentinel-2B Imagery

Lake Tempe is located in three districts, namely Wajo, Sidenreng Rapang, and Sopeng, South Sulawesi. The water quality in Lake Tempe needs to be considered both the quality and the quantity of the water. Total Suspended Solid (TSS) is one of the calculations and analysis of air quality. The large of TSS distribution can overcome the effects of sedimentation thereby reducing the need for lakes in saving water. TSS distribution at Lake Tempe can be accessed through Sentinel2B imagery with acquisition time 10 April 2019 and spatial resolution of 10 meters. The algorithm used is NSMI (Normalized Suspended Material Index) algorithm then the results are compared with TSS measurements result in the field. The time of the study was conducted in April 2019 at Lake Tempe, South Sulawesi. The result from samples showed various TSS value which is in the range of 65 mg/L to 203 mg/L with R2of 0.1194 and standard deviation of 8.7106. High TSS value on the banks of the North lakes also had high sedimentation. Low TSS value are in the middle of the lake with small sedimentation and deeper lake