沉积物核心切片和孔隙水萃取缺氧条件下
Summary
A protocol for sectioning sediment cores and extracting pore waters under anoxic conditions in order to permit analysis of redox sensitive species in both solids and fluids is presented.
Abstract
我们演示了切片沉积岩芯和提取孔隙水，同时保持无氧状态的方法。一个简单，廉价的系统构建，可以运到一个临时的工作空间接近现场采样网站（），以方便快速分析。芯被挤压成一个便携式手套袋中，在那里它们被切片并每1-3厘米厚的部分（取决于芯直径）被密封到50ml离心管中。孔隙水用离心分离的手套袋中的外面，然后返回到手套袋用于从沉淀分离。这些提取出来的孔隙水样品可立即进行分析。氧化还原敏感的物种，如硫化物，铁形态，和砷的形态的直接分析表明孔隙水的氧化最小;一些样品显示没有可检测的Fe（III）还原物种的约100％， 例如 100％的Fe（Ⅱ）。这两种沉积物和孔隙水样可以保存到主一旦返回到实验室覃用于进一步分析的化学物质。
Introduction
研究人员常常希望来研究沉积物 – 水系统的氧化还原状态和地质微生物学。这理想地利用来自两个沉积物和孔隙水的数据，孔隙水通常是系统的敏感显示器和是一个公共源，虽然不是唯一的源，生态暴露于氧化还原敏感性重金属1如砷和铀。孔隙水数据可以原位使用扩散平衡滤波器，也称为“皮珀斯，”安装到沉积物2来获得。偷窥者都在外地网站之前开始现场工作，并在那里过的很长一段时间多次访问可以到野外现场进行， 例如 Shotyk 3闻名设置最常用的。因此，许多情况下不允许使用皮珀斯，如站点只有很短的时间内可以访问或者获得多个探样品，以确定进一步的调查应该发生4。此外皮珀斯不同时采样沉积物水样采集。
当希望采样沉淀物和水一起，或在该领域网站，偷窥安装是不可行的，最常用的方法，以获得沉淀物和水是沉积物核化。获得未混合芯是一个关键的前体在此工作5描述的过程。一旦获得芯孔隙水可以通过挤压6或离心来获得;都具有优点和缺点。离心通常被认为是提取沉积物岩芯，7孔隙水虽然必须小心，以防止或沉积物孔隙水的氧化最可靠的方法。
在这种方法中，我们描述的核心挤出和离心提取孔隙水以最小的氧化。作者使用在各种上下文包括海洋8的本文中所描述的方法中，被污染的湖泊<sup> 9，和湿地10。示出的具有代表性的数据表明，在还原条件得以保存。用离心机之外，使用的材料是廉价的，而且这种方法可以适用于各种各样的地球化学和地球微生物研究问题。
Protocol
Representative Results
Discussion
本文所描述的技术是一种灵活的，能够为各种各样的位置，芯尺寸，芯部厚度等 ，有此系统的三个主要组分进行调整。
首先，准备正确尺寸的芯挤压系统，用于将待分析的核心。这里给出的说明假设一个大约30“芯;长得多芯可能需要更多的PVC增量剂件和PVC管件完全挤出如本领域的更正是困难得多管理计划的挤压系统和仔细的包装，。
其次，确保?…
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
这项研究部分由美国国家科学基金会的快速程序（NSF-1048925，1048919，和1048914）艾莉森Keimowitz，明郭李笃Okeke，和詹姆斯·桑德斯的支持。
Materials
| Disposable glove bag(s). | Sigma-Aldrich | Z106089-1EA | One per two cores to be processed is usually sufficient. |
| N2 tank | Praxair | Often gas supply companies can deliver these directly to the field laboratory. | |
| Nitrogen gas regulator | VWR | 55850-478 | Or similar |
| Several feet of tubing that fits the regulator | VWR | 89403-862 | Or similar |
| Safety equipment to secure the tank | VWR | 60142-006 | |
| Adjustable tubing clamp | VWR | 62849-112 | |
| Waterproof, good sealing electrical tape | Scotch | Super 33+ | Widely available |
| 2-4 short bungee cords | Widely available | ||
| Squirt bottles of nanopure water | VWR | 16650-082 | Any similar bottle is fine; pack an additional supply of nanopure water to refill these. |
| Large supply of paper towels and kimwipes. | Widely available | ||
| 50 mL centrifuge tubes | VWR | 21008-951 | Acid cleaned as described in protocol. At least 2/core section needed. |
| Several permanent in markers. | Widely available | ||
| Several straight razor blades and box cutters. | Widely available | ||
| Centrifuge | Beckman-Coulter | Allegra X-22 | Faster rotor allows greater separation. |
| Rotor to accommodate 50 mL tubes | Beckman-Coulter | SX-4250 | |
| ]50 mL plastic syringes without black rubber tip on the barrel | VWR | 66064-764 | Acid cleaned as described in protocol. At least 1/core section needed, plus 1 for overlying water. |
| Syringe filters compatible with aqueous solutions. | VWR | 28143-310 | Either 0.45 μm or 0.20 μm poresizes may be used. Plan on five filters per core section processed. |
| Plastic (disposable) spoons. | Widely available; Acid cleaned as described in protocol. | ||
| Several boxes of disposable gloves. | Widely available | ||
| Large plastic beakers or other waste containers to place in the glove bag. | VWR | 13890-148 | |
| Laboratory balance | VWR | 10205-008 | An available balance will be fine; high precision not required |
| Dry shipper, pre-charged with liquid nitrogen | VWR | 82005-416 | Needed only if samples are being returned to the home laboratory for sensitive analyses. |
| Laboratory notebooks | Water repellent can be useful | ||
| Core liners | Watermark | 77280 | Available from Forrestry Suppliers |
| Core caps | Ben Meadows | 218105 | |
| Core slicers | McMaster Carr | 8707K111 | Cut this into 9 3×3 squares |
| PVC spacers | McMaster Carr | 48925K96 | Cut this into short lengths |
| PVC couplings | McMaster Carr | 4880K76 | Approximately 12 needed |
| Dowel | Widely available | ||
| Lab stopper | VWR | 59580-400 | Check to ensure the correct size to fit snugly within the core liners |
| Plywood for core guidance plate and top of lab jack | Widely available | ||
| Lab jack | VWR | 89260-826 | |
| Clamps | Widely available | ||
| Portable oxygen monitor | RKI instruments | OX-07 |
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