A Remotely Operated Serial Sampler for Collecting Gas-Tight Fluid Samples

This paper describes the design, construction and preliminary test results for a gas-tight serial sampler intended to be deployed at seafloor for long-term operation to take time-series fluid samples from deep-sea environments such as cold seeps, water column and hydrothermal vents. The serial sampler is a modular system that is based on independent and identical sampling modules, which are designed to collect six 160 ml gas-tight fluid samples maintained at high pressure to a depth of 4000 meters. With two working modes, the sampler can be deployed either with seafloor cabled observatory for remote control or as a stand-alone device for autonomous operation. A prototype of the instrument has been constructed and tested on the MARS cabled observatory for two months. The laboratory and field tests proved the success of the design and construction of the serial sampler, and indicated the potential for future ocean sciences.     

A new gas-tight isobaric sampler for hydrothermal fluids

A new gas-tight isobaric sampler for the collection of hydrothermal fluids venting at the seafloor has been designed, constructed, and tested at a ridge-crest vent site. The new device is constructed of chemically inert titanium, is gas-tight to 450 bar and can be used to sample fluids with temperatures up to 400°C. Compressed gas is used to maintain the sample at seafloor pressure before and during sample withdrawal onboard ship, allowing subsampling without degassing the fluid remaining in the sampler. This feature eliminates the need to collect separate gas-tight and major element samples since a single fluid sample can be analyzed quantitatively for major, trace, semi-volatile, and volatile components. The sampler fill rate is regulated to minimize entrainment of ambient seawater during collection of fluids from environments characterized by low fluid flow such as diffuse hydrothermal vents. In addition to deployment at the ridge-crest, the samplers can be used to collect gas-tight samples from other subseasurface environments such as hydrocarbon seeps, areas of methane-gas hydrate formation, cold seeps associated with serpentinites, regions of groundwater egress to the oceans, and the water column.     

A sampler for concentrating radionuclides from natural waters

A sampler which permits concentration of both particulate and dissolved radionuclides from large volumes of ocean and freshwater has been developed and tested. The water sample passes through a filtration section for particle removal, then through a sorption section where the radionuclides of interest are removed on sorption or ion exchange beds. Components of the sampler which contact the water are of polyvinyl chloride construction, and flow rates of about 40 l./min are employed. This sampler has been successfully employed in concentrating some twenty radionuclides from ocean and fresh waters.     

Field measurements of time-averaged suspended sediment concentrations under waves

A suction sediment sampler has been developed for sampling suspended sand in the field. It works by the pressure difference between seabed and water surface, and thus no pump is required. The fact that the sampler has no mechanical moving parts and no electronics makes it very dependable. Seven samples are taken simultaneously at different elevations starting at about 1 cm above the bed. The sampling time is about 3 min for water depths of about 1.5 m. Sixty-five concentration profiles, complete with hydraulic data and sediment characteristics are given in the appendix.     

Two samplers for large-volume collection of chlorinated hydrocarbons

Two sampling devices for the in situ extraction of chlorinated hydrocarbons from water are described. Both samplers use the macroreticular adsorbent Amberlite XAD-2. They include a “fish” sampler which has been used to collect samples for PCB analysis from waters around the British Isles. Operation of this sampler causes a minimum of interruption to a ship's cruise programme and at the same time allows a large area to be surveyed. The second sampler is a self-powered in situ pump which is cheap to construct and can be left unattended to extract large volumes of water at a fixed station. The device is serviced by divers and samples may be collected daily on a routine sampling basis.     

A Novel Mechanical Gas-Tight Sampler for Hydrothermal Fluids

A new mechanical gas-tight sampler has been designed to collect hydrothermal fluids at the seafloor. A key feature of the sampler is the novel sample valve which is pressure balanced under deep sea, and actuated by the ram on a submersible's manipulator. The sampler is designed to be deployed at the seafloor 3000 m underwater and can be used to sample hydrothermal fluid with temperature up to 400degC. Compressed gas is used to compensate for pressure reduction of sample fluids. Simulation of the flow system was conducted to estimate the fill rate. The sampler has been tested successfully in the first Sino-American Cooperative Deep Submergence Project from August 13 to September 3, 2005.     

A comparative study of energy performance of hydrostatic seafloor sediment samplers and a new high-efficiency sampler

The hydrostatic energy of high-pressure seawater is a renewable and green energy source for ocean exploration and have been used to replace underwater electrical energy transmission through the cable and underwater battery pack to power seafloor equipment. The advantage of the energy supply method is the cost-effective and the robustness. In the paper, the energy performance of the existing hydrostatic seafloor sediment samplers powered by seawater hydrostatic energy are modelled and analyzed and compared. In view of the common shortcoming of existing technology, a novel hydrostatic seafloor sediment sampler is proposed. The model of energy conversion of the new sampler is built, and its energy performance is obtained. The analysis results indicate that the energy conversion efficiency of the novel sediment sampler is much higher than the existing ones, which means that the new sampler can collect much longer sample with the limited amount of hydrostatic energy. The seawater hydrostatic energy conversion system of the new sampler can also be used to power other seafloor equipment.     

A simple,inexpensive and large volume pore water sampler for sandy and muddy substrates

The construction and testing of a low cost, simple, intertidal and sub-tidal pore water sampler for use in sandy and muddy substrates are described in this note. The sampler, “porextractor”, is made of polyvinyl chloride (PVC) plumbing materials that can be readily sourced at any local hardware shop and costs AU $ 15.00 to build. The only mechanical component of the porextractor is a plunger that is used only once at the time of deployment. The porextractor has been designed for use on seagrass beds to collect pore water samples with minimal disturbance to the substratum for nutrient flux studies. The relative efficiency of the porextractor was tested against the widely used “Winger and Lasier” sampler, a vacuum operated diffuser stone pore water sampler. The two samplers were compared for the volume of pore water collected in sandy and muddy substrates in the laboratory, and the concentrations of total nitrogen and total phosphorus in samples collected from a sandy substrate in Amphibolis and Posidonia seagrass meadows off the Adelaide coast. While the porextractor and the Winger and Lasier samplers worked equally well in the sandy sediments, the porextractor was more efficient than the latter in muddy sediments, where clogging was a major problem. In addition, there were no significant differences (p ≤ 0.05) in the concentrations of total nitrogen and total phosphorus measured from the pore water samples collected by the two samplers in situ from the seagrass bed. The simplicity, ease of construction, non-substrate specificity, and large sample volume yield are some of the major merits of the porextractor over other conventional techniques used for pore water sampling.     

On the tuning of a wave-energy driven oscillating-water-column seawater pump to polychromatic waves

Performance of wave-energy devices of the oscillating water column (OWC) type is greatly enhanced when a resonant condition with the forcing waves is maintained. The natural frequency of such systems can in general be tuned to resonate with a given wave forcing frequency. In this paper we address the tuning of an OWC sea-water pump to polychromatic waves. We report results of wave tank experiments, which were conducted with a scale model of the pump. Also, a numerical solution for the pump equations, which were proven in previous work to successfully describe its behavior when driven by monochromatic waves, is tested with various polychromatic wave spectra. Results of the numerical model forced by the wave trains measured in the wave tank experiments are used to develop a tuning criterion for the sea-water pump.     

沉积物对磷酸盐的吸附与释放

本实验研究黄河口水文站沉积物对黄河水磷的吸附释放过程和东海１１１号站位沉积物对海水磷的吸附释放过程。并摸拟黄河沉积物在海水中磷的吸附释放过程。结果表明：底沉积物对磷的吸附相当迅速，无论是河泥还是海泥在２４ｈ内均能达到吸附平衡。吸附量与沉积物的量和水中原有磷的浓度有关，在不同的ｐＨ条件下，沉积物对磷的吸附是有显著差别的     

A new microsplitter for unconsolidated sediments

Unrepresentative subsamples can be obtained from a sedimentary sample through repeated subdivision when using a mechanical microsplitter. Physical biases are often compounded by repetition and can result in wide variations among the estimates computed from the relative proportion of foraminifera of a given species. A new microsplitter, designed on a new principle, has been built to separate small representative subsamples. The device is based on the uniform distribution of unconsolidated sediments suspended in water. A subsample of the desired size is obtained by collecting sediment from an appropriate sedimentation area. Operation of this sampler is rapid and convenient and requires only one step, thus eliminating sampling biases introduced by repeated operations with other splitters. This new device was tested and found to be superior to the Otto Microsplitter according to some statistical goodness-of-fit tests conducted on the series.     

冲绳海槽中南部柱状沉积物氧化还原敏感元素赋存机理与环境指示意义

沉积物中氧化还原敏感元素(Redox Sensitive Element,RSE)含量变化是上覆水体氧化还原环境良好的替代指标。本文通过冲绳海槽中南部两个柱状沉积物(深度：30 cm)粒度、总有机碳、总氮及其同位素含量和氧化还原敏感元素含量等指标,探究复杂环境背景下冲绳海槽柱状沉积物中RSE的赋存机理与环境指示意义。研究发现,柱状沉积物中除了Cr亏损,其他RSE均显示有不同程度的富集。“粒控效应”对冲绳海槽柱状沉积物的RSE含量影响较小;分析可知,海水表层生产力是影响沉积物氧化还原环境的主要因素,通过Mn(氢)氧化物的吸附或解吸附作用实现RSE的富集与亏损。δCe、V/Cr、Ni/Co和V/(V+Ni)等指标指示沉积物整体处于氧化-弱氧化环境。沉积物中Mn元素通过还原作用以Mn²⁺形式向上扩散,在25～30 cm处被含氧间隙水氧化富集形成锰峰,指示柱状沉积物0～25 cm处为氧化环境,25～30 cm处为弱氧化环境。     

A new, automatic hydrothermal fluid sampler using a shape-memory alloy

A new hydrothermal fluid sampler has been developed to provide more maneuverability in underwater operation. The sampler characteristically employs a shape-memory alloy, which senses high temperature and actuates the suction mechanism. A shape-memory alloy is also used to switch the intake valve of the sampler, the intention being to avoid missampling when the inlet is in low temperature water. Prototype samplers were designed to collect the fluids hotter than 80°C. Test sampling was performed at hydrothermal vents (1372–1374 m deep) in the submarine volcano, Suiyo Seamount, Izu-Bonin Arc, northwestern Pacific. Observed fluid temperature was between 138 and 298°C, while the ambient seawater temperature was 3.1°C. Each prototype collected about 100 ml fluid as designed. The magnesium concentration in the samples indicated a seawater content of 47.5–90.8%, which indicates the entrainment of ambient seawater. Microscopic observatinn revealed the occurrence of microorganisms in the sample fluids at a population density of 10⁵ to 10⁶ cells ml⁻¹, which is 2–3 orders of magnitude higher than those in seawater at that depth. The use of the newly developed fluid sampler will greatly facilitate the collection of vent-associated microorganisms, which are of potential biological and biotechnological interest.     

海水中硝酸盐铜镉柱还原测定操作步骤的优化研究

本文比较了硝酸盐测定的铜镉柱还原法在两个规范中技术指标和操作工艺的差异.针对本实验室具体条件,对该测定方法的某些步骤(如镉柱制备、蠕动泵、流速选择、加氯化铵缓冲液方法等)进行优化研究,选择适宜的改进方法,以便将硝酸盐铜镉柱还原测定方法结合进本实验室已有的营养盐测定系统中.     

Benthic Disturbance and Impact Experiments in the Central Indian Ocean Basin

As a part of the Environmental Impact Assessment studies for nodule mining, a long-term program has been initiated in the Central Indian Basin. Multidisciplinary studies on geological, biological, physical, and chemical parameters were carried out in an area selected on the basis of baseline data collected in the first phase of the program. A benthic disturbance was simulated with a hydraulic device also used in the previous experiments in the Pacific Ocean. A site of 3,000 ×200 m was repeatedly disturbed by a combination of fluidizing pump and suction pump to dislodge and discharge sediment from the seafloor into the water column 5 m above the seafloor. During 9 days of operation, 26 tows were carried out for 47 h of disturbance, resuspending about 6,000 m 3 of sediment along an 88-km line. Data for postdisturbance impact assessment were collected with sediment traps, deep-towed cameras, seafloor samples, and conductivity-temperature depth sensor (CTD)-rosette observations. Seafloor data, sediment samples, and water column studies were aimed at evaluating the impact of benthic disturbance, on the basis of pre- and postdisturbance data collected during the experiment. Observations show that vertical mixing of sediment as well as its lateral movement and resedimentation because of plume migration alters various parameters and leads to changes in the environment around the area.     

The carbohydrate‐to‐protein ratio as a biological indicator of water movement

We investigated temporal (day‐to‐day and season) and spatial (reach) variability of drift with the aim of guiding sampling protocol for quantifying drift at the whole river or reach scale. Overall, we found aquatic drift density and biomass varied considerably seasonally (CV = 72.9, 88.1) and to a lesser extent spatially (CV = 31.3, 30.7) and from day‐to‐day (CV = 45.2, 39.4). Although spatial and day‐to‐day variation in drift density and biomass were similar, sampling logistics suggest spatial sampling would be more cost‐effective and less time consuming. Drift density and biomass estimated from top samplers was often higher than estimates from samplers near the streambed or mid‐water column. A reliable estimate of mean densities and biomass at a site may require only two samplers— a top sampler and either a middle or bottom sampler. In our study, we calculated that sampling at four sites over 1 or 4 days at one site would be required to obtain a 95% CI within 50% of the mean drift density. Eight sites over 1 or 10 days at one site would be required to achieve a 95% CI within 25% of the mean drift density.     

基于镀铜镉柱海水中硝酸盐氮的检测技术的研究

镀铜镉柱还原——重氮偶氮染色法在检测海水领域具有重要的位置,算法的不断创新优化成为海水水质检测质量的的关键.本研究以硝酸钾作为标准溶液,海水作溶剂做相关实验,并且在实际海水检测应用中得到良好的效果.通过对实验原理的分析及实验过程的探究,确定了本研究的最佳还原与显色条件.并采用偏最小二乘法(partial least s...     

The organic carbon pump in the Atlantic

The growth, sinking and remineralisation of phytoplankton constitute the soft-tissue carbon pump. Here we derive the expression for the strength of this carbon pump in terms of the nutrient utilisation and the carbon:nutrient ratio of plankton. Furthermore, we aim to determine how the physical environment affects this carbon pump. Thereto, we have used a plankton physiological model with a novel representation of the effect of temperature and light on plankton stoichiometry; it predicts that the effect of temperature on the carbon:nutrient ratio depends on the light conditions. Using this model combined with a mechanistic model for the mixed layer, we have studied the biological carbon pump at the BATS site and at various locations along a meridional transect through the Atlantic Ocean. Our results suggest that the soft-tissue carbon pump is stronger at mid-latitudes than in the (sub-)tropics and near the poles as a consequence of latitudinal variations in algal stoichiometry.     

In situ filtration sampler for taking filtered water samples

A new type ofin situ filtration sampler is described. The all Teflon sampler is hung on a nylon rope attached to a steel wire (Fig. 3). By dropping a messenger, the sampler piston is pulled down by a released weight of 50 kg, and the sampler is filled with about 400 ml of filtered water. The sample is not contaminated by metals because there is no metal around the sampler.