Name: estimating sediment denitrification rates using cores and n2o microsensors
Uploaded: 2018-12-06T13:00:00
Description: Watch this Scientific Journal Video about Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors at JoVE.com

西班牙政府通过教育部长司向 c. p-l. (FPU12-00644) 提供资金, 并向经济和竞争事务部长提供研究赠款: nitropir (cglap-19737)、lacus (cgl2013-45提48-p), 调动 (cglp2016-80121-c2-p)。reptim 项目 (inre-interreg 方案)。欧盟-欧盟。efa05615) 支持协议的最终编写。

1. 准备工作
注: 在进行测量的前一天开始此操作。
<ol><li>组装测量设置 (图 1a, 见材料表)。 注: 为确保恒定和高质量的电源, 测量设备通过不间断电源 (ups ) 连接到手柄, 该电源也可用作备用电源。在长时间断电的情况下, 汽车电池可作为额外的电源。</li>
	<li>启动传感器的软件, 并应用-0.8 v 电压来极化 n 2o 微<...

<ol>
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该方法的主要优点是使用了最小扰动沉积岩心样品和连续记录 n2o积累。这样就可以估计相对较低的反硝化率, 这可能与就地发生的反硝化率相似。尽管如此, 还是讨论了有关取心、传感器性能和潜在改进的一些方面。
该方法的一个明显简单但关键的步骤是良好的核心恢复。沉积物/水界面必须满足三个标准: (一) 不改变其化学或组成成分, (二) 不改变含水量或孔?...

氮循环的人为改变是地球系统1最具挑战性的问题之一。人类活动使生物圈2的活性氮水平至少增加了一倍。然而, 在如何评价全球 n 周期方面仍然存在很大的不确定性。一些通量估计已被量化, 误差小于±20%, 许多具有±50% 和更大的 3倍的不确定性。这些不确定因素表明, 需要准确估计整个生态系统的反硝化率, 并了解潜在的变化机制。脱氮是一种微生物活性, 通过这种活性, 氧化氮, 主要是硝酸盐和亚硝酸盐, 还原为二氮、n2o 和 n24.该途径与活性氮的生物圈供应高度相关, 因为它是去除5的主要过程.n2o 是一种温室气体, 其升温潜能值是100年来二氧化碳的近 300倍, 是目前平流层臭氧消耗的主要原因, 其排放量为6,7.
在下面, 我们提出了一个协议, 用于估计沉积物反硝化率使用岩心和n 2o 微传感器实验 (图 1)。反硝化率是使用乙炔抑制方法8、9和测量在规定时间段内积累的氮2o(图 2和图 3)。我们通过将其应用于山湖沉积物来证明该方法。本案例研究突出了在对沉积物物理结构干扰最小的情况下检测相对较低速率的方法的性能。
反硝化特别难以测量10。有几种替代方法和方法, 每种方法都有优点和缺点。对现有方法的缺点包括使用昂贵的资源、灵敏度不足以及需要使用受干扰的样本修改基板水平或改变过程的物理配置10.测量n2 的一个更根本的挑战是它在环境中的背景水平升高10。乙炔 (c2h2)8、9抑制了 n2o至n2 的还原.因此, 反硝化可以通过测量在 c2h2 存在下的累积 n2o来量化, 这是可行的, 因为环境氮2o 水平较低。
大约40年前 11年, 利用 c2h2 测量沉积物中的反硝化率, 12年后大约12年后, 氮-2o传感器的加入发生. 应用最广泛的乙炔方法是 "静态核心"。在将 c2h2 添加到密封沉积物岩心10的头部空间后, 在长达 24小时的潜伏期内测量累积的氮2o.此处描述的方法遵循此过程和一些创新。我们通过在核心的水相中冒泡气体几分钟来加入 c2h2, 然后用微传感器测量 n2o的积累, 然后用样品水填充所有的头部空间.我们还包括一个搅拌系统, 防止在不重新悬浮沉积物的情况下对水进行分层。该程序量化了每个沉积物表面积的反硝化率 (例如, μmoln 2o-2 h-1 ).
反硝化的高时空变化给反硝化的准确量化带来了另一个困难10。通常情况下, 在孵化过程中采集的前空间样品的气相色谱法可按顺序测量 n 2o 积累。所述方法改进了对 n2o积累的时间变化的监测, 因为微传感器提供了一个连续的信号。微传感器万用表是一种数字微传感器放大器 (皮安计), 与传感器和计算机接口 (图 1a)。万用表允许同时使用多个n2o 微传感器。例如, 可以同时测量同一研究地点最多四个沉积物岩心, 以考虑到空间的变异性。
与其他一些方法 (如泥浆) 相比, 岩心方法几乎不会干扰沉积物结构。如果改变沉积物的完整性, 这将导致不现实的反硝化率 13,这只足以进行相对比较。与岩心方法14相比, 浆料法总是得到较高的速率, 因为后者保留了基板扩散15反硝化的局限性。泥浆措施不能被视为就地率16的代表;它们为与完全相同的程序进行比较提供了相对的措施。
所述方法适用于估算任何可以被岩心的沉积物类型的反硝化速率。我们特别推荐一些驱动因素的实验操作方法。例如, 根据估计反硝化17的能量活化 (e a) 所需的需要修改硝酸盐的可用性和温度的实验 (图 2).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58553/58553fig1v2.jpg"> 图 1: 实验设置.(a) 利用岩心和 n2o 微传感器估计沉积物反硝化率的一般实验设置。孵化器可确保黑暗和控制温度 (±0.3°c) 的条件。五个完整的沉积物岩心可以使用各自的 n2o传感器同时处理。(b)n2o传感器校准室。我们用橡胶塞子和注射器将其与 n2o水混合 (参见协议步骤 3.4.3)。有一个温度计来控制水温。(c) 将沉积物芯样品特写, 将传感器插入 pvc 盖的中央孔, 用胶带密封接头。搅拌器悬挂在水中, 电磁铁靠近它, 并固定在丙烯酸管的外部部分。(d) 由金属片保护的 n2o微传感器尖端的特写镜头。(e) 刚刚回收的沉积物岩心。它是从深湖中的一条船上取样的;核心的丙烯酸管仍然固定在送声机适应的重力取样器19上。有关执行此方法所需的所有项, 请参阅材料表。<a href="https://www.jove.com/files/ftp_upload/58553/58553fig1v2large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>

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			<td height="63" style="height:63px;width:227px;">Messenger-adapted gravity corer</td>
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			<td style="width:203px;">Reference in the manuscript. Made by Glew, J.</td>
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		<tr height="20">
			<td height="20" style="height:20px;width:227px;">Sampling tube</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Acrylic. Dimensions: 100 cm (h) &#215; 6.35 cm (d) &#215; 6.50 cm (D). Sharpen the edge of the sampling tube that penetrates into the sediment to minimize the disturbance in the recovered sediment core sample.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Handheld sounder</td>
			<td style="width:65px;">Plastimo</td>
			<td style="width:100px;">38074</td>
			<td style="width:203px;">Echotest II Depth Sounder.</td>
		</tr>
		<tr height="128">
			<td height="128" style="height:128px;width:227px;">Rubber stopper</td>
			<td style="width:65px;">VWR</td>
			<td style="width:100px;">DENE1012114</td>
			<td style="width:203px;">With two holes, used to mix the N2O-water in the calibration chamber. Dimensions: 20 mm (h) &#215; 14 mm (d) &#215; 18 mm (D) (3 mm hole (D)).</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:227px;">Rubber stopper</td>
			<td style="width:65px;">VWR</td>
			<td style="width:100px;">217-0125</td>
			<td style="width:203px;">To seal the bottom part of the methacrylate tube and to sample in shallow water bodies. Dimensions: 45 mm (h) &#215; 56 mm (d) &#215; 65 mm (D).</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:227px;">PVC cover</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">To seal the top side part of the acrylic tube. Dimensions: 45 mm (h) &#215; 56 mm (d) &#215; 65 mm (D). Dimensions: 65 mm (D).</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:227px;">Adhesive tape</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Waterproof. To ensure all joints (PVC cover sampling tube and PVC cover sensor) and to avoid water leaks.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:227px;">Thermometer</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Portable and waterproof, to measure the temperature in the water overlying the sediment just after sampling the cores.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:227px;">GPS</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">To save the location of a new sampling site or to arrive at a previous site.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Wader</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">For littoral or shallow site samplings.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:227px;">Boat</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">An inflatable boat is the best option for its lightness if the sampling site is not accessible by car.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:227px;">Rope</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Rope with marks showing its length (e.g., marked with a color code to distinguish each meter).</td>
		</tr>
		<tr height="44">
			<td height="44" style="height:44px;width:227px;">N2O gas bottle and pressure reducer</td>
			<td style="width:65px;">Abell&#243; Linde</td>
			<td style="width:100px;">32768-100</td>
			<td style="width:203px;">Gas bottle reference.</td>
		</tr>
		<tr height="44">
			<td height="44" style="height:44px;width:227px;">C2H2 gas bottle and pressure reducer</td>
			<td style="width:65px;">Abell&#243; Linde</td>
			<td style="width:100px;">32468-100</td>
			<td style="width:203px;">Gas bottle reference.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:227px;">Tube used to evacuate the excess of water</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Consists of a solid part (e.g., a 5 ml pipette tip without its narrowest end) inserted in a silicone tube.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Nitrous Oxide Minisensor w/ Cap</td>
			<td style="width:65px;">Unisense</td>
			<td style="width:100px;">N2O-R</td>
			<td style="width:203px;">We use 4 sensors at a time.</td>
		</tr>
		<tr height="235">
			<td height="235" style="height:235px;width:227px;">Microsensor multimeter 4 Ch. 4 pA channels</td>
			<td style="width:65px;">Unisense</td>
			<td style="width:100px;">Multimeter</td>
			<td style="width:203px;">Picoammeter logged to a laptop. The standard device allows for 2 sensor picoammeter connections (e.g., N2O sensor), one pH/mV and a thermometer. We ordered a device with four picoammeter connections, allowing the use of 4 N2O sensors simultaneously.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">SensorTrace Basic 3.0 Windows software</td>
			<td style="width:65px;">Unisense</td>
			<td style="width:100px;"></td>
			<td style="width:203px;">Sensor data acquisition software.</td>
		</tr>
		<tr height="107">
			<td height="107" style="height:107px;width:227px;">Calibration Chamber incl. pump</td>
			<td style="width:65px;">Unisense</td>
			<td style="width:100px;">CAL300</td>
			<td style="width:203px;">Calibration chamber. We tuned it with rubber stoppers and syringes to mix the N2O-water without making bubbles.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:227px;">Incubation chamber</td>
			<td style="width:65px;">Ibercex</td>
			<td style="width:100px;">E-600-BV</td>
			<td style="width:203px;">Indispensable equipment for working at a constant temperature (&#177;0.3 &#176;C). It also allows control of the photoperiod.</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:227px;">Electric stirrer</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Part of the stirring system. It hangs in the water, overlying the sediment subject, by a fishing line that is hooked to the PVC cover.</td>
		</tr>
		<tr height="252">
			<td height="252" style="height:252px;width:227px;">Electromagnet</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Part of the stirring system. It is fixed to the outside of the acrylic tube, approximately at the same level as the stirrer. It is activated episodically (ca. 1 on-off per s) by a circuit, attracting the stirrer when it is on and releasing it when it is off, thereby generating the movement that agitates the water.</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:227px;">Electromagnetic pulse circuit</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">Part of the stirring system. It is connected by wires to the electromagnet and sends pulses of current that turn the electromagnet on and off.</td>
		</tr>
		<tr height="170">
			<td height="170" style="height:170px;width:227px;">Uninterruptible power supply (UPS)</td>
			<td style="width:65px;">-</td>
			<td style="width:100px;">-</td>
			<td style="width:203px;">It improves the quality of the electrical energy that reaches the measurement device, filtering the highs and low of the voltage, thereby ensuring a more constant and stable N2O sensor signal.</td>
		</tr>
	</tbody>
</table>

estimating sediment denitrification rates using cores and n2o microsensors

脱氮是从生物圈中去除活性氮的主要生物地球化学过程。对这一过程的定量评价对于评估人类年龄改变的全球氮循环和温室气体 (即n2o) 的排放尤其重要。有几种方法可用于测量反硝化, 但都不能完全令人满意。现有方法的问题包括灵敏度不足, 以及需要使用扰动样品修改基板水平或改变工艺的物理配置。本工作介绍了一种估算沉积物反硝化率的方法, 该方法结合了取心、乙炔抑制和累积的 n-o 的微传感器测量。该方法的主要优点是对沉积物结构的干扰较小, 并收集了 n2o积累的连续记录;这些使可靠的反硝化率的估计, 最小值高达 0.4μmoln 2o-2-1. 操纵关键因素的能力是获得实验洞察的另一个优势。该协议描述了收集核心、校准传感器、抑制乙炔、测量 n 2o 积累和计算反硝化率的程序。该方法适用于估算任何具有可回收沉积物岩心的水生系统的反硝化率。如果 n2o浓度高于传感器的检测极限, 则可以省略乙炔抑制步骤来估计 n2o排放量, 而不是反硝化。我们展示了如何通过增加硝酸盐的可用性以及过程的温度依赖性来估计实际和潜在的反硝化率。阐述了利用山湖沉积物的工艺, 并讨论了该技术与其他方法相比的优缺点。此方法可以为特定目的进行修改;例如, 它可以与15个n 个示踪剂结合起来, 以评估硝化和反硝化或现场的反硝化率测量。

2013-2014年期间, 使用上述议定书估计, 在 pyrenean 山区湖泊的沉积物中, 共估计了468个反硝化率。我们展示了其中的一些结果来说明这个过程 (图 2和图 3)。一般情况下, n2o浓度与时间之间的线性模型具有良好的相关性 ( r 2≥0.9)。关系的斜率提供了反硝化率的估计 (步骤 7.3;例如,图 2<stron...

Watch this Scientific Journal Video about Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors at JoVE.com

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

该方法利用乙炔抑制技术和累积的 n-o 的微传感器测量, 估计沉积物岩心中的沉积物反硝化率。该协议描述了收集核心、校准传感器、抑制乙炔、测量 n 2o 积累和计算反硝化率的程序。

利用岩体和 n 2o 微传感器估计沉积物脱氮率

Denitrification is the primary biogeochemical process removing reactive nitrogen from the biosphere. The quantitative evaluation of this process has ...

该方法有助于回答生物地球化学中与沉积物中与理解氮循环和温室气体排放相关的关键问题。该技术的主要优点是沉积物结构的低扰动和氮氧化物积累的容器记录，以进行可靠的利化率估计。对于深水体，根据调查目标选择采样点。使用 GPS 坐标记录位置，并使用手持式声器测量深度。部署信使适应重力腐蚀系统，直到采样管距离沉积物大约一米。将取样设备稳定60秒，确保沉积物正确渗透，并回收几乎没有扰动的沉积物芯。释放大约一米的绳索，使采样管穿透沉积物。请注意，如果采样管穿透太多，可能会干扰水沉淀界面。释放信使，同时尝试保持绳索中的张力，使芯保持固定，并处于垂直位置。通过不断和轻轻地拉绳来恢复芯。一旦芯器靠近表面但仍完全淹没，请将橡胶塞放在取样管的底部。将整个腐蚀系统从水中提升。检查水沉淀界面。它应该是明确的，而不是明显不安。从芯中释放样品管，并在顶部放置 PVC 盖。用胶带密封管，避免形成空气空间。当从字面生境和浅水体取样时，穿着涉水服在非常浅的水域取样。手动将取样管插入沉积物中。将橡胶塞放在取样管的顶部，以获得真空。从沉积物中拆下芯器，并在管底快速引入另一个橡胶塞。对于零一氧化二氮的校准值，首先读取传感器信号，使传感器尖端淹没在去电化水中。要以所需浓度校准一氧化二氮水，在去化水中冒泡一氧化二氮，获得一氧化二氮饱和水几分钟。通过将特量的饱和一氧化二氮水添加到一卷去化水中，稀释一氧化二氮饱和水。将一氧化二氮饱和水与校准容器中的去化水轻轻混合，以稀释至所需的浓度。混合溶液时，注意不要产生气泡，因为这样会消除校准溶液中的一氧化二氮。现在，当传感器信号保持不变时读取它。此读数是 X 微摩尔一氧化二氮水的校准值。将位于每个沉淀芯顶部的 PVC 盖更改为另一个盖，中间有一个孔和一个悬挂的磁搅拌器。用胶带重新密封接头。将每个样品的水相减至大约 12 厘米的高度。为此，首先在中央孔中插入硅管。然后将沉淀芯放入气缸中，然后推动底部塞子以产生压力。塞子和沉积物样本上升，多余的水通过管。在接收容器中收集水。在芯的水相中冒泡乙烯气体约10分钟，执行乙烯抑制。避免重新悬浮沉积物。在密封结点传感器 PVC 盖之前，用先前的剩余水填充所有空气空间。通过顶部 PVC 盖的中心孔将传感器放在沉淀芯中。传感器的尖端应位于搅拌器上方的水相中。打开作为搅拌系统一部分的电磁脉冲电路。将电磁铁围绕丙烯酸管的外部部分移动，直到搅拌器连续移动，然后用胶带将电磁铁固定到位。关闭孵化室以确保恒定温度。按传感器软件上的记录按钮开始记录传感器信号。然后在测量周期结束时按下停止按钮。在读取零一氧化二氮校准措施的信号之前，将传感器的尖端浸入自由一氧化二氮水中至少等待 10 分钟。执行最终传感器校准后，使用传感器软件保存文件。要执行广体化率计算，请从传感器软件生成的表格输出文件开始，该文件包含传感器以毫伏和微摩尔一氧化二氮表示的信号记录以及校准数据。将传感器的信号与时间保持一致，以可视化一氧化二氮的累积趋势。仅使用具有线性累积的时间范围，不包括样品的初始适应周期和由于基板限制而可能的最终饱和度。2013-2014年，在比利牛山山湖的沉积物中，利用这一协议估计了该议定书的去硝化率。在这里，从湖计划测量不添加硝酸盐。测量是嘈杂的，只有在某些情况下，可以正确估计速率。在此图中，添加硝酸盐的相同样本显示更稳定的读数和对潜在速率的准确估计。虽然此过程近似于利化并查看速率，但也提供了一种实验性地改变控制此活动的关键因素的方法。要测试温度和基材，不要忘记，良好的温度控制是良好和稳定测量的根本。此外，在岩芯收集过程中，不受干扰的沉积物-水界面是可靠估计的第一个关键要求。按照此过程，还可以结合其他方法（如 N15 比率）来研究硝化、除尼化耦合和其他氮循环过程。

Research

JoVE Journal

Environment

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

Measuring Rates of Herbicide Metabolism in Dicot Weeds with an Excised Leaf Assay

测量除草剂代谢的双子叶杂草价格与切下的叶片分析

In order to isolate and accurately determine rates of herbicide metabolism in an obligate-outcrossing dicot weed, waterhemp (Amaranthus tuberculatus), we ...

科研

环境科学

Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions

沉积物核心切片和孔隙水萃取缺氧条件下

We demonstrate a method for sectioning sediment cores and extracting pore waters while maintaining oxygen-free conditions. A simple, inexpensive system is ...

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

农业流域营养盐和泥沙的连续河道监测

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in ...

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

使用 DMAv为环境应用 DMMTAv和 DMDTAv的准备: 合成、纯化和确认

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic ...

Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris

高悬浮泥沙荷载和大型漂浮碎屑水生环境中 Microplastics 的取样、分类和表征

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only ...

Laboratory and Field Protocol for Estimating Sheet Erosion Rates from Dendrogeomorphology

利用树形地貌估算板材侵蚀速率的实验室和现场协议

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to ...

Investigation of Plant Interactions Across Common Mycorrhizal Networks Using Rotated Cores

旋转芯在常见菌根网络中植物相互作用的研究

Arbuscular mycorrhizal (AM) fungi influence plant mineral nutrient uptake and growth, hence, they have the potential to influence plant interactions. The ...

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

基于14NH 4 + /4+ 15NH 4= 通过顺序转换为 N2O 的分析，测量异化硝酸盐降低至铵的潜在率

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has ...

Sampling for Estimating Frankliniella Species Flower Thrips and Orius Species Predators in Field Experiments

Sampling for Estimating Frankliniella Species Flower Thrips and Orius Species Predators in Field Experiments

现场实验中估计富兰克林菌种花纹和奥里乌斯物种捕食者的取样

The western flower thrips, Frankliniella occidentalis (Pergande), is a polyphagous pest that has been spread worldwide. The extensive use of insecticides ...

Enhanced Oil Recovery using a Combination of Biosurfactants

使用生物表面活性剂组合提高石油采收率

Biosurfactants are surface-active compounds capable of reducing the surface tension between two phases of different polarities. Biosurfactants have been ...