Distribution and Seasonal Variation of Microplastics in Tallo River, Makassar, Eastern Indonesia

Attention towards microplastic (MP) pollution in various environments is increasing, but relatively little attention has been given to the freshwater-riverine environment. As the biggest city in the eastern Indonesia region, Makassar can be a potential source of MP pollution to its riverine area. This study aimed to determine the spatial trends, seasonal variation, and characteristics of MPs in the water and sediment of Tallo River, as the main river in Makassar. Water samples were collected using a neuston net and sediment samples were collected using a sediment corer. The samples collected contained MPs with an abundance ranging from 0.74 ± 0.46 to 3.41 ± 0.13 item/m3 and 16.67 ± 20.82 to 150 ± 36.06 item/kg for water and sediment samples, respectively. The microplastic abundance in the Tallo River was higher in the dry season and tended to increase towards the lower river segment. Fragments (47.80–86.03%) and lines (12.50–47.80%) were the predominant shapes, while blue (19.49–46.15%) and transparent (14.29–38.14%) were the most dominant color. Polyethylene and polypropylene were the common MP polymers found in the Tallo river. Actions to prevent MP pollution in the Makassar riverine area are needed before MP pollution becomes more severe in the future.

Efisiensi Teknik Sampling dalam Penentuan Indeks Keanekaragaman Polychaeta di Padang Lamun Pantai Sire, Lombok Utara

Padang lamun merupakan salah satu ekosistem yang berperan sebagai tempat tinggal, tempat mencari makan, tempat pembesaran dan daerah pemijahan bagi sejumlah besar biota asosiasinya, termasuk polychaeta. Selain mengambil manfaat dari tumbuhan lamun, polychaeta juga berperan terhadap kesuburan substrat lamun karena kemampuannya dalam menguraikan serasah dan meningkatkan kadar oksigen dalam sedimen melalui aktivitas bioturrbasi. Penelitian ini bertujuan untuk mengetahui indeks keanekaragaman polychaeta di padang lamun Pantai Sire, Lombok Utara menggunakan 2 (dua) teknik sampling yang berbeda. Pengamatan data lamun dilakukan menggunakan kuadran 50x50 cm2, dengan 3 (tiga) transek dimana masing-masing terdapat 10 titik pengamatan. Pengambilan sampel polychaeta dilakukan menggunakan alat Ekman Grab dan PVC sediment corer. Hasil penelitian menunjukkan bahwa terdapat 5 (lima) jenis lamun dan 17 famili polychaeta di perairan padang lamun Pantai Sire, dimana Capitellidae merupakan jenis dengan rerata kelimpahan tertinggi (1.046±32,34 - 1.430±37,82 individu/m2). Hasil uji-t menunjukkan bahwa perbedaan teknik sampling berpengaruh terhadap total kelimpahan polychaeta di padang lamun, dimana teknik sampling menggunakan PVC sediment corer memiliki hasil yang lebih optimal dibandingkan mengunakan Ekman Grab. Hal tersebut menandakan bahwa alat PVC sediment corer lebih efisien digunakan untuk pengambilan sampel polychaeta di lamun karena sesuai dengan karakteristik substrat lamun yang berpasir. Sedangkan alat Ekman Grab lebih baik digunakan pada substrat berlumpur dan pada perairan yang cenderung dalam. Seagrass bed is one of the ecosystems that act as a place to live, foraging for food, rearing and spawning areas for a large number of associated biota, including polychaeta. Apart from taking advantage of seagrass, polychaeta also plays a role in the fertility of seagrass substrate because of its ability to break down litter and increase oxygen levels in the sediment through bioturbation activity. This study aims to determine the diversity index of polychaeta in seagrass bed at Sire Beach, North Lombok using 2 different sampling techniques. Seagrass data observation was carried out using a 50x50 cm2 quadrant, with 3 transects, each of which had 10 observation points. Polychaeta samples were taken using the Ekman Grab and the PVC sediment corer. The results showed that there were 5 specieses of seagrass and 17 families of polychaeta in seagrass of the Sire Beach, where Capitellidae was the species with the highest average abundance (1,046 ± 32.34 - 1,430 ± 37.82 individuals / m2). The t-test result shows that the different sampling techniques have a correlation to the total abundance of polychaeta, where PVC sediment corer has more optimal results than using Ekman Grab. This indicates that the PVC sediment corer is more efficient to use for polychaeta sampling in seagrass because of its suitability to the characteristics of sandy seagrass substrate. Meanwhile, the Ekman Grab is better to use on muddy substrates and in a deep water.

A new percussion hammer mechanism for a borehole deployable subglacial sediment corer

Subglacial sediments have the potential to reveal information about the controls on glacier flow, changes in ice-sheet history and characterise life in those environments. Retrieving sediments from beneath the ice, through hot water drilled access holes at remote field locations, present many challenges. Motivated by the need to minimise weight, corer diameter and simplify assembly and operation, British Antarctic Survey, in collaboration with UWITEC, developed a simple mechanical percussion corer. At depths over 1000 m however, manual operation of the percussion hammer is compromised by the lack of clear operator feedback at the surface. To address this, we present a new auto-release-recovery percussion hammer mechanism that makes coring operations depth independent and improves hammer efficiency. Using a single rope tether for both the corer and hammer operation, this modified percussion corer is relatively simple to operate, easy to maintain, and has successfully operated at a depth of >2130 m.

A Study of Nutrient Distribution in Sediment Layer at Sembrong Dam

Reservoir is one of the key sources of water supply as it provides hydroelectric power, domestic usage, agriculture, farming, recreation and provides flood protection. Sedimentation in the reservoir makes the storage of water loss and the sediment sink contain a source of nutrients. Sediment deposition creates habitats for aquatic life but if too much sediment, it can destroy their habitats and even physically alter a waterway. The use of nutrients such as Total Phosphorus (TP) is key to growing plants and animals thus to feed growing populations. An excess of nutrients in the reservoir such as from agricultural activity makes algae growth rapidly and it can affected the water quality in the reservoir. This research was conducted at the Sembrong dam as this dam is a major water source for people in Kluang and parts Batu Pahat and the water quality become decreased because of algae bloom. The main objective of this study is to determine the distribution of nutrient in different location and to determine the nutrient distribution in vertical sediment layer. The study were conducted by taking sediments samples throughout the reservoir by using sediment corer and the sediment have been sliced every 5 cm. The samples were digested using USEPA Method 3050B which is acid digestion for sediments, sludge and soil for TP. The laboratory testing on these nutrients was conducted by following Standard Method for the Examination of Water and Wastewater (APHA, 1999) using spectrophotometer. The highest value of TP obtain is at outlet of the reservoir which is 30.72 mg/l. The results obtained shows that the top of sediment has high number of TP and it decreasing by depth. However, continuous and periodic monitoring should be done to avoid the increasing of the concentration of TP in the sediment to ensure the life of Sembrong dam can be extending for future.

Probe technologies for clean sampling and measurement of subglacial lakes

It is 4 years since the subglacial lake community published its plans for accessing, sampling, measuring and studying the pristine, and hitherto enigmatic and very different, Antarctic subglacial lakes, Vostok, Whillans and Ellsworth. This paper summarizes the contrasting probe technologies designed for each of these subglacial environments and briefly updates how these designs changed or were used differently when compared to previously published plans. A detailed update on the final engineering design and technical aspects of the probe for Subglacial Lake Ellsworth is presented. This probe is designed for clean access, is negatively buoyant (350 kg), 5.2 m long, 200 mm in diameter, approximately cylindrical and consists of five major units: (i) an upper power and communications unit attached to an optical and electrical conducting tether, (ii)–(iv) three water and particle samplers, and (v) a sensors, imaging and instrumentation pack tipped with a miniature sediment corer. To date, only in Subglacial Lake Whillans have instruments been successfully deployed. Probe technologies for Subglacial Lake Vostok (2014/15) and Lake Ellsworth (2012/13) were not deployed for technical reasons, in the case of Lake Ellsworth because hot-water drilling was unable to access the lake during the field season window. Lessons learned and opportunities for probe technologies in future subglacial access missions are discussed.

Reliability Assessment of the Water Distributing Valve of a Hydrostatic Sediment Corer

The hydrostatic corer is designed for sampling sediment from the seafloor. Its operation relies on a water distributing valve which converts the potential pressure difference between ambient seawater and a built-in chamber with atmospheric pressure to the dynamic energy as the driving power. As the valve is exposed to the ambient water, the deformation of its components may exceed their fitting tolerance under the high pressure and low temperature on seafloor, and thus cause the failure of the valve. Three possible failure modes have been taken into account, representing the positions where interference of fitting tolerance is likely to occur. Corresponding models are then created considering the coupled effects of pressure and temperature on the valve. Based on the model results and the reliability requirement of the corer, one failure mode is selected to calculate the reliability of the valve and is used as guidance for the future improvement of the design.

A Novel Active Seafloor Pressure-Retained Multitube Sediment Corer

A novel minimally disturbed seafloor pressure-retained sediment corer driven by a self-served underwater fluid power system is presented. It features multiple independent two-stage cylinders with a piston rod to mount a core liner that can be penetrated into sediment and pulled back at a controllable speed. Each core tube is equipped with two ball valves to retain the in situ pressure of the seafloor sediment. The corer can be monitored in real time and controlled from the deck via a coaxial cable, such that operators onboard can choose the proper coring location, control the coring speed, and collect multitube pressure-retained cores in different sites during one deployment. The test prototype is equipped with only two tubes and deployed at a depth of 1,035 m in the South China Sea by the R/V Dayang No. 1 of China. Two tubes of sediment cores with in situ pressure retained have been successfully obtained.

Implementation of a Seafloor Sediment Corer With a Novel Hydrostatic Motor

This work deals with the design and application of a seafloor sediment corer with a novel hydrostatic motor. The motor uses seawater pressure energy as the power for the penetration by the sediment corer. It is automatically triggered by mechanical linkage when the corer lands on the seafloor, enabling the corer to accomplish an initial gravity penetration before the motor is activated. As a key feature of the motor, a hydraulically actuated valve is employed to control the transfer of ambient high-pressure seawater to a vacant chamber. Driven by the pressure transfer, the corer head continuously repeats movements of lifting and lowering, analogous to a pile driver. Since the motor directly uses the seawater as the energy transmission medium, the corer can be very compact in size. The prototype of the sediment corer with the motor was tested in the East China Sea at a depth of 90 m on September 25, 2011. The results of the experiment show that the corer is able to complete nearly 42 hammering action cycles. This demonstrates the feasibility of the seafloor sediment corer with the hydrostatic motor. By extrapolation, the application of the system to deep sea environs, such as at 1,000 m depths, is shown to be feasible as well.