作者非常感谢詹姆斯·斯密特和库尔特·汤普森提供的现场和实验室的援助。资金筹措而此协议被开发的原始研究是由春湖湖董事会2,13,18,19提供;环境质量4的密执安部门;和吉姆-邓肯，大卫Farhat的，和总统办公室在大峡谷州立大学17。

1。野外采样<ol><li>每一个无冰季节进行采样一次（如适用）为1-2年，如果可能的话（ 即 3次/年的北温带气候）。如果时间和/或资金禁止季节采样，在中期到夏末进行采样，每年一次。 </li><li>选择沉积物收集网站内湖覆盖不同的地理区域。接近历史水质和/或沉积物采样点，当有选择的地点，经常需要利用历史数据的优势。否则，试图选择代表在湖沉积物不同类型的网站。 </li><li>进行水质采样之前，去滓核心种质。 <ol><li>至少，测量水深，水温和溶解氧的垂直廓线。近底部的测量应被视为接近沉积物表面成为可能，而不会干扰沉淀物。 </li><li>收集任何其他笏呃质量数据和样品所期望的满足研究的具体目标。实例包括pH，电导率，和浊度的垂直剖面;沙奇深度;光合有效辐射（PAR）的访问; 叶绿素 a;可溶性活性磷（SRP）;总磷（TP）和氮物种。 </li></ol></li><li>在每个采样位置，填充10升大玻璃瓶收集与以上1米用凡德恩或Niskin瓶沉积物地表水。这将在实验室中沉积物岩心的初始设置和培养过程中取样后回填内核使用。将瓶子在有冰的凉爽。 </li><li>收集每个站点6沉积物岩芯用活塞取样器2,20。 <ol><li>请参阅费舍尔等人 20有关建设核化装置的具体说明。简要地，核化装置由一个刻度0.6米长聚碳酸酯芯管（7厘米内径），聚氯乙烯（PV的C）连接组件，用于耦合到铝驱动杆，两个橡胶瓶塞和一个有眼螺栓，带旋转夹塑料涂层的活塞电缆，铝及驱动杆构成的活塞。按照下面的步骤组装的核化装置： <ol><li>通过PVC连接组件的顶部螺纹活塞电缆的回转夹具端部。定向芯管朝上的螺栓孔，并通过在芯管的长度延伸的线。夹在活塞电缆连接到活塞止动眼螺栓。 </li><li>用钢丝锁栓销连接在芯管的PVC连接组件。拉活塞缆推进活塞20厘米的芯管的底部，保持水层上的沉积物表面的芯收集过程中顶部。 </li><li>附加的铝传动杆用钢丝锁栓销的PVC连接组件的另一端。较低的取芯器垂直插入水中，加入铝驱动器的其他部分根据需要棒。 </li></ol></li><li>垂直放置取样器在沉积物 - 水界面和向下推，与活塞连接线保持静止。要做到这一点，拉活塞电缆拉紧，一旦取样器是在发生在沉积物 - 水界面，安装副把手电缆，踩线副把手的内侧，然后向下推。 </li><li>带芯的表面和密封用橡胶塞破水表面之前。固定瓶塞底部用胶带。 </li><li>用螺栓将活塞到芯管的顶部在运输过程中保持其静止状态。将芯管垂直机架，并在室温近底湖的温度保持，使用冰，如果必要的。 </li></ol></li></ol> 2。培养实验<ol><li>在从该字段返回，调节芯含有沉积物和上覆水柱的期望深度。过量沉积可小心让出在芯管的由r中的底emoving底部的塞子;如果需要从在相应的网站所收集的瓶子加水。常用的沉淀物和水柱的深度是用25厘米覆水柱2,4,13,17-1920厘米的沉淀物，但随意这些值可以被修改。 </li><li>将沉积物岩心管放入一个黑暗的环境生长室，以保持匹配在现场测得的环境下水温的温度。 </li><li>暴露在核氧化还原处理。对于好氧处理，泡3芯/网站与空气的水柱。泡泡每个站点的其余三个核心与N 2的水柱（含〜350ppm的二氧化碳缓冲pH值）对缺氧的治疗。确保一个缓慢的和一致的气泡速度是不中断的沉积物表面。 </li><li>对核心孵化的第1天，过滤含有从现场每个站点收集的近底水各10升的瓶子。用蠕动泵和过滤器滤芯壳体，过滤器的水首先通过一个1微米的过滤器，接着用0.2μm的过滤器。店铺过滤后的水在4℃的孵化核心的持续时间。 </li><li>样品为核心在潜伏期2,3的持续时间磷释放速率。因为这是一个氧化还原敏感的实验，采取预防措施，以尽可能保持氧化还原处理的条件。 <ol><li>用注射器，通过对天0（ 即在芯被放置在生长室中的时间），1，2，4，6，8，12，20，24各沉积物芯的取样口取出40毫升的水样本和芯孵育28。 （注：如果在非常短的时间段的变化是理想的，采样机制可以被修改以每小时1，2，4，8， 等等来样但是，该系统通常仍然通过第一12小时达到平衡，因此磷的释放动力可以相当变数在孵化的开始。） </li><li>立即移除后，取20毫升0;子样本到闪烁瓶中并冷藏总磷分析。通过0.45μm膜过滤器并进入闪烁瓶中过滤其他20毫升子样本和冻结SRP的分析。 </li><li>用过滤后的水相等体积（见步骤2.4）从相应的现场更换40毫升子样本的。 </li></ol></li></ol> 3。磷释放率的计算<ol><li>计算基于使用下面的等式2中的水柱TP或SRP的变化通量（释放率）： P RR =（C T - C 0）×V / A 其中P RR为净磷释放（正值）或保留（负值）每沉积物的单位表面积（毫克P / M 2次 / d）率，C t是t时刻在水柱中的TP或SRP浓度，C 0是在时间0的TP或SRP的浓度，V是水在核心吨水柱的体积宇部兴产，而A是沉积岩芯的平面面积。计算使用浓度的线性部分与时间的关系曲线，得到的最大表观释放速率4,13,18,19磷的释放速率。为了避免潜在的短线偏向，选择不连续的采样时间为C T和C 0 18,19。 </li></ol> 4。内部P负荷计算<ol><li>计算每年的P通量。 <ol><li>对于在此期间，采样发生在每个季节，由天在那个赛季的数量分别乘以缺氧和好氧通量。总结季节性值产生的年度缺氧和好氧通量（毫克/ 平方米 /年）。如果多个站点在同一个湖中进行取样，这种计算可以单独对每个站点或使用平均流量值，对所有站点（见4.2.2节）。 </li><li>冬季由于低水温时沉积物磷的释放通常是非常低的。如果采样冬季期间没有进行，假设p流量为0的那个赛季14,15。 </li><li>因为大多数内部磷释放的夏季发生，每年的内部P通量可以从粗夏季单独测量在没有季节性的数据2,15,17的估计。对于这种方法，根据第4.1.1节计算在P通量和假设0通量的所有季节，除了夏天。认识到这将是每年的磷释放的保守估计。 </li><li>如果可用，溶解氧数据可被用于细化年度P通量计算2,4。这样的数据可以表明，湖泊经历低氧或缺氧一定比例的一年，或在特定的季节。在这种情况下，按照适当比例或季节使用缺氧和好氧通量和总结的值来计算每年的内部P通量。 <ol><li>例如，如果低氧或缺氧是暑假期间仅测量，利用夏季和好氧通量缺氧通量计算第4.1.1节其余季节。总结的值来获得年度内部P通量。同样，如果日常溶解氧的监测数据表明，湖泊经历低氧或缺氧一年的35％，由0.35和年度好氧通量从第4.1.1节由0.65乘以每年缺氧通量从第4.1.1节和总结的值来计算每年的内部P通量。 </li></ol></li><li>复成分的湖泊构成了特别的挑战，以内部P负荷计算，由于其频繁的混合和时空变化在氧化还原条件14。纽伦堡等 16开发了一个模型来计算的缺氧天复成分湖可能在一个季节或一年经历数。主动底泥释放区和时间（AA），它代表的时间长度（天/季），一个区域类似湖面面积正在积极释放P，可以计算如下： AA = -36.2 + 50.2日志（P 赛季 ）+ 0.762 Z / A 0.5 其中P是一个特定季节中的平均水体总磷浓度，z为平均深度，A是湖水面面积。要计算年度内部P通量，乘AA级缺氧通量和好氧天数由好氧通量每个季节，再总结的所有值。 </li></ol></li><li>内部P通量扩展到了整个湖面面积。 <ol><li>由整个湖面面积从步骤4.1乘以每年的P通量来计算每年的内部P负荷。除每年的P通量是根据第4.1.4或4.1.5计算，使用无氧年通量来计算每年的内部P负荷。否则，使用第4.1.4或4.1.5计算的通量。 </li><li>如果多个站点在同一湖泊进行取样，湖水，可分为每个站点相关联的地理区域。由区域的面积乘以每年的反硝化除磷效果通量（或从第4.1.4或4.1.5每年光通量）为每个站点，然后求和值，以获得安UAL内部P负荷为整个湖面4,17。另外，所有站点的年平均P通量可以在第4.2.1节中使用。 </li><li>详细的溶解氧数据可能表明湖泊经验低氧或缺氧条件下（ 例如深地区 ​​），特定地区，而其他地区仍然好氧全年。如果可以，请使用此信息来改进通量×面积计算（斯坦曼等人，在准备）。通过每年的缺氧通量乘以缺氧表面积和年度好氧通量乘以好氧表面积，总结这两个值来计算每年的内部P负荷。 </li></ol></li></ol>

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S., Kristensen, P., Jeppesen, E., Skytthe, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron:phosphorus+ratio+in+surface+sediment+as+an+indicator+of+phosphate+release+from+aerobic+sediments+in+shallow+lakes.">Iron:phosphorus ratio in surface sediment as an indicator of phosphate release from aerobic sediments in shallow lakes.</a> Hydrobiologia. 235-236, 731-743 (1992).</li><li>Roychoudhury, A. N., Viollier, E., Van Cappellen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+plug+flow-through+reactor+for+studying+biogeochemical+reactions+in+undisturbed+aquatic+sediments.">A plug flow-through reactor for studying biogeochemical reactions in undisturbed aquatic sediments.</a> App. Geochem. 13, 269-280 (1998).</li></ol>

作者什么都没有透露。

富营养化湖泊可能导致环境和经济障碍21-23，因此，至关重要的是，社会理解的营养源的性质以及如何管理它们。昂贵的尝试，以减少营养物负荷可能无法改善水质，如果适当的贡献源（ 如湖泊沉积物或流域投入）未针对管理行动，从而导致湖泊恢复和挫折对利益相关者的一部分挫折。特别是在浅水富营养化湖泊，内源磷负荷的量化是在确定一个管理策略，以改善水质条件的关键步骤。即使当沉积物被牵连作为营养素的主要来源，减少外部P负载必须包含在减轻富营养化湖泊的任何管理策略，因为磷外部投入，最终积累在沉积物和燃料未来内部装载24,25 &lt;/ SUP&gt;。 虽然其他的方法存在估计内部P负荷，实验测定磷的释放速率是一个直接的方法，可以进行调整，以回答各种管理和研究的问题。从春天湖，密歇根采集沉积物岩心的实验室孵化，被用来确定明矾处理2和最高效的应用浓度13的潜在效益。由于这些实验室为基础的研究发现的结果，利益相关者开发的信心，明矾治疗可以控制在春天湖沉积物磷释放。因此，他们批准了一项10年的评估，以资助明矾处理;随后沉积岩芯孵化显示，该治疗是有效减少泥沙P通量1 年 17年和5年以下19治疗。沉积物核心的孵化也被用于评估沉积物再悬浮13的影响</SUP&gt;和生物扰动对磷的释放（G.诺加罗和A.哈里斯，未发表资料）。 几个额外的沉积物的分析可以与核心的孵化提供了在解释底泥磷释放业绩的有用信息一并进行。前5或10厘米沉积物可以从内核的沉积物总磷，孔隙水SRP，逐次P分馏，和金属4,18,19分析被挤压。逐次P分馏26的一个例子，可以在内部装载的研究是有用的涉及确定的P势必1）的铝（Al-P）或铁（Fe-P），它表示一个氧化还原敏感（铝-P）和量氧化还原敏感的（Fe-P系），矿物组合缺氧条件下，可以成为可溶的，和2）钙（Ca-P）或镁（Mg-P），它们都是稳定的矿物组合。另外，沉淀的Fe：P比值可以计算出，以提供对沉积物的电位的P-结合能力的洞察力。富含铁的沉淀物仍然存在氧化已被证明以释放非常小P时的Fe：P比值高于15（重量比）27。这些额外的沉积物的分析可以在以下核心内部负载孵育4,18,19进行，或在内部负载核心种质的时间拍摄，但不用于释放速率测量的复制核心。 尽管实验测定沉积物P通量的优势，该方法也不是没有限制的。一些假设必须经常进行，可以添加不确定性的结果： <ul><li>其中一个假设是，释放速率的沉积物岩芯有代表性的研究湖泊的条件。为了尽量减少这种假设的影响，取样策略的设计应代表尽可能多的空间和时间变化尽可能在底泥磷释放的。采样点应涵盖尽可能多的地理范围内尽可能湖捕捉到的沉积物characterist空间变化ICS 2。如果可以，等深线图，可以用来选择网​​站是代表在湖底深处的范围。其他考虑因素捕捉空间变化包括主要支流输入的位置和不同的湖盆的存在。如果可能，实验室孵化应在每个无冰季节，持续数年进行捕捉释放速率随时间的变化。 </li><li>第二个假设是，培养条件具有代表性的自然条件。恒定缺氧条件创造了P的释放理想情况下，这可能不是自然发生的研究湖泊。因此，缺氧的治疗可能高估底泥磷释放，因此，它可能是最好的去思考在缺氧的治疗作为最大的潜在税率计量释放速率。 </li><li>为了计算年度内部P负荷，约的时间，持续时间和hypolimnetic缺氧的空间范围必须做出一些假设。例如，在强烈分层湖泊相对一致的水深，并确认hypolimnetic缺氧，一些研究认为，整个湖面面积在分层期为每年的内部P负荷估算2,4的 ​​目的缺氧。但是，这可能会导致负载的高估是由于沿岸浅水区4好氧沉积物。因此，全面的溶解氧监测策略，捕捉昼夜，季节，而在氧化还原条件的空间变异强烈建议准确的年度内部负荷估算。 </li><li>最后，实验室孵化可能会引入实验文物由于无法完全模拟自然条件。例如，由于沉淀物被包围在芯管，通过可渗透沉积物水交换被排除，但是，它是可以设计出减轻此问题28流过芯管。其他文物包括无法模仿的主要混合事件或风浪作用，这可能会破坏自然系统沉积物的完整性。 </li></ul>鉴于沉积岩芯孵化方法可以用来生成在短短按一年合理的内部P负荷预测（尽管多年的数据提供更强大的信息），它是通知湖泊管理决策的重要工具。当用于开发湖泊管理和恢复计划，它可以帮助确保明智地使用财政资源。在已经发生内部P负荷管理，其中湖泊，沉积物核心的孵化可以验证其疗效，并可以用来修改管理的轨迹，如果必要的。

随着越来越多的世界各地的湖泊，从文化富营养化受苦，测定水质恶化的原因正在成为湖泊管理和恢复越来越重要。磷（P）装载到湖泊通常牵连的富营养化，因为它是最常见的营养限制藻类生长1。从历史上看，磷负荷在湖泊量化通过点和非点源集中于外部来源，或P原产于分水岭。然而，从湖泊沉积物内源负荷可以占到很大一部分在富营养化湖泊2-5全磷负荷，如果不是大多数，。因此，即使大幅降低外部负载的湖泊可能会失败，导致水质改善是由于从5-8沉积物磷释放的首要作用。因为磷负荷的生态和社会影响，包括成本和P控制的难度是P加载是，重要的是准确识别制定管理策略之前。 至少两种不同的机制负责磷的释放沉积物。 1）在缺氧或缺氧期间，还原条件下可导致磷酸铁羟基氧化物沉积物-水界面的脱离，从而导致从沉积物溶解磷酸盐扩散进入水柱9-11。沉积物表面的2）干扰，通过风引起的再悬浮和扰动，可以通过解吸磷从再悬浮的沉淀颗粒，或从沉积物孔隙水中释放溶解磷的水柱导致P的释放到水柱，分别为11-13。 三种主要的方法可用于量化内部P装载到湖泊14,15。 （1） 在变化hypolimnetic总磷（TP），随着时间的现场测量时，可以使用监控数据是可用的。 在现场测量的基础上的内部负荷估计从环境数据的内在空间和时间变化相关的高可变性受苦，会受到监管不力频率14。 （2）质量平衡可以被用来估计内部负载，当全部比例的预算可以构造。然而，它是罕见的，足够的数据都可以在P投入和出口来构建一个全部比例的预算16。 （3）实验确定沉积物磷的释放速率可以使用，在与区域范围磷的释放（ 即缺氧期）和持续时间的信息，计算出内部P荷载组合。这是内部P加载量化的直接方法，尽管它也有它的局限性（参见下文）。 因为管理的决策往往要在压缩的时间进行缩放由于资金限制或社会压力，实验测定内部的P负载可以有湖泊管理和恢复更大的效用，因为它需要比现场和质量平衡的方法更少的时间和数据。沉积物岩心，结合监测外部负载的实验室孵育，已被用来确定内部和外部的P加载的相对贡献，以指导管理决策，以优化营养源控制2,4,17的目标。二密歇根湖与在子流域直接相邻的湖泊岸线粗放发展和不透水面高比例（&gt; 25％），内部P负荷估计占高达80％的总磷负荷，促使建议将重点放在减少沉积物磷释放2,4管理工作。与此相反，沉积物来自同一地区欠发达湖实验研究表明，内源负荷只由7％的总磷负荷，促使建议，对焦第管理策略在华tershed 17。沉积物岩心实验也已经被用在密歇根湖，以确定硫酸铝（明矾）治疗的潜在效益，以减少沉积物磷的释放率2，最有效的明矾加药浓度，沉积物再悬浮13的效果，一个企业的疗效原位明矾治疗1 年 17年和5年以下19治疗。内部P负荷实验测定是一种有效的方法来提供答案在富营养化湖泊的密钥管理问题。

<table border="0" cellpadding="0" cellspacing="0" width="1118">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Multiparameter sonde</td>
			<td style="width:219px;">YSI</td>
			<td style="width:95px;">YSI 6600</td>
			<td style="width:167px;">The key parameters of interest are temperature and dissolved oxygen, although other measurements may be desired depending on the goals of the study. The other major manufacturer of multiparameter sondes is Hach (Hydrolab).&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Niskin bottle</td>
			<td style="width:219px;">General Oceanics</td>
			<td style="width:95px;">101005</td>
			<td>A Van Dorn bottle can also be used.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Carboys, 10 L&#160;</td>
			<td style="width:219px;">Nalgene</td>
			<td>DS2213-0020</td>
			<td>Available from many laboratory supply companies, including Fisher Scientific and VWR.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Piston corer</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td>Details on construction materials given in Fisher et al. 1992</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Vice grips</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Duct tape</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Vertical rack for holding core tubes</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td>Custom fabricated on-site.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Environmental growth chamber</td>
			<td style="width:219px;">Powers Scientific, Inc.</td>
			<td style="width:95px;">DS70SD</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Compressed air with regulator</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td>Use lab air supply or purchase from local gas supply company.</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:639px;">Buffered N2 gas with regulator</td>
			<td style="width:219px;">N/A</td>
			<td style="width:95px;">N/A</td>
			<td>Purchase from local gas supply company.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Parker Parflex Series E (instrument grade) polyethylene tubing; 1/4&#34; o.d., 0.04&#34; wall, .170&#34; i.d.</td>
			<td style="width:219px;">Parker</td>
			<td style="width:95px;">E-43-B-0100</td>
			<td>Tubing (from gas to chamber)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">PEEK Capillary tubing; 1/16&#34; o.d., 1/32&#34; i.d.</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td style="width:95px;">3050412</td>
			<td>Tubing (from manifold to cores)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Union tee</td>
			<td style="width:219px;">Parker</td>
			<td style="width:95px;">164C-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Union tee nut</td>
			<td style="width:219px;">Parker</td>
			<td style="width:95px;">61C-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Nylon tubing; 1/4&#34; o.d., 3/16&#34; i.d.</td>
			<td style="width:219px;">US Plastics</td>
			<td style="width:95px;">58042</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Ferrule, front and back; 1/4&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-400-Set</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Brass nut; 1/4&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-402-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Brass medium-flow meterings valve; 1/4&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-4MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Once-piece short finger tight fittings; 1/16&#34;</td>
			<td style="width:219px;">Alltech</td>
			<td style="width:95px;">32070</td>
			<td>Half of the sampling port</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Female 10-32 to female luer; 1/4 &#34;</td>
			<td style="width:219px;">Alltech</td>
			<td style="width:95px;">20132</td>
			<td>Half of the sampling port</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Ferrule, front and back; 1/16&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-100-Set</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Brass nut fittings; 1/16&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-102-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Tube fitting reducer; 1/16&#34; x 1/4&#34;</td>
			<td style="width:219px;">Swagelock</td>
			<td style="width:95px;">B-100-R-4</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:23px;width:639px;">PTFE tubing; 1/16&#34; o.d., 0.040&#34; i.d.</td>
			<td style="width:219px;">Grace Davison Discovery Sciences</td>
			<td style="width:95px;">2106982</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Low-pressure PTFE tubing; 1/8&#34; o.d., 0.1&#34; i.d.</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td style="width:95px;">AT3134</td>
			<td>Tubing from sampling port into core</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">AirTite all-plastic Norm-Ject syringes, 50mL (60mL) luer slip (eccentric), Sterile</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td>14-817-35</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Wheaton HDPE liquid scintillation vials, 20 mL, Poly-Seal cone liner</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td>03-341-72D</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Nylon Syringe Filter; 30mm diameter, 0.45 mm</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td style="width:95px;">03-391-1A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Masterflex peristaltic pump, model 755490</td>
			<td>Cole Parmer</td>
			<td>A-77910-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Pall Filterite filter housing, model T911257000</td>
			<td style="width:219px;">Pall Corporation</td>
			<td style="width:95px;">SCO 10UP</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Graver QMC 1-10NPCS filter; 10&#34;, 1.0 mm</td>
			<td>Flowtech Corp</td>
			<td style="width:95px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Graver Watertec 0.2-10NPCS filter; 10&#34;, 0.2 mm</td>
			<td>Flowtech Corp</td>
			<td style="width:95px;">N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

laboratory-determined phosphorus flux from lake sediments as a measure of internal phosphorus loading

富营养化是全球水质问题，湖泊，有一个关键的需要确定和控制营养源。从湖泊沉积物内源磷（P）的加载可以解释在富营养化的总磷负荷的主要部分，还有一些营养型湖泊。沉积物岩心实验室测定的磷释放速率是一种方法，用于确定内部磷负荷的作用，并指导管理决策。实验测定沉积物磷释放的两个主要备选方案估计内部负载存在：随着时间的推移和P物质平衡变化hypolimnetic磷原位测量。使用基于实验室的沉积物孵育来量化内部的P负荷实验方法是一种直接的方法，使其成为湖泊管理和恢复的重要工具。 沉积物岩心的实验室孵化可以帮助确定内部与外部P负荷的相对重要性，以及用来解答各种湖泊管理和研究的问题。我们说明了使用沉积物核心孵化，评估的硫酸铝（明矾）治疗减少底泥磷释放的效果。可以使用这种方法进行调查等研究的问题包括沉积物再悬浮和生物扰动对磷释放的影响。 这种方法也有其局限性。假设必须就提出：沉积物岩心整个湖外推结果，决定在什么时间段来衡量养分释放，以及解决可能的芯管的文物。一个全面的溶解氧监测策略，以在湖中评估的时间和空间的氧化还原状态提供了更大的信心，从沉积物核心的孵化估计全年P加载。

内部P释放从收集在莫娜湖，密歇根沉积物岩芯测定，以确定内部与外部P负载4的相对贡献。四个地点进行抽样超过三个赛季来估算年度内部P负载，占空间变化P中的磁通。沉积物岩心孵育缺氧和好氧条件下20-28天，发病期间上覆水体取样进行SRP和总磷浓度定期。缺氧处理引发SRP和从沉积物总磷的释放，但是，我们只列出TP通量结果仅供说明之用。总磷浓度在缺氧的治疗夏季最高，并在所有季节中总磷的释放空间变异性明显（ 图1）。意味着内部TP通量为小于1.4毫克P / m 2 /天在所有好氧芯; 3的下落过程中的4个位点的负通量的值表明好氧沉积物s者作为一个接收器，而不是P的来源，第4季（ 表1）中。总磷释放率相当高的在缺氧的核心，具有通量高达15.56毫克磷/ 平方米 /天，夏天和低至春季4（ 表1）0.80毫克P / 平方米 /天。这些光通量值被用来计算基于在沉积物核心种质4时测得的溶解氧条件下季节性内部P通量。季节性内部P负荷进行了计算扩大磁通在每个站点到相应的地理区域4的表面面积;季节性值进行求和来估计每年的内部P加载，假设在冬季0通量。年度内部P负荷估计为3.4万吨，与广大夏季（ 表2）期间发生的负载。这些结果与并发外部P负荷预测相比，据估计，在蒙娜丽莎贡湖沉积物之间的每年总P加载4的9-82％TE（ 表2）。 一系列的实验是在春天湖，密歇根进行的，以确定硫酸铝（明矾）治疗在减少内部磷负荷2和一个2） 原位明矾治疗18,19的功效1）的潜在效益。实验室实验模拟明矾的湖泊广泛的应用体现在内部的磷释放的大幅下降与治疗2（ 图2）。类似于上面的例子中，我们从这些实验中只提出目标价发行作为代表性的结果。在缺氧的核心无明矾处理（模拟自然条件下夏春湖沉积物），平均总磷浓度上覆水体达到了超过1.2毫克/升（ 图2）。相比之下，服用明矾缺氧内核实际上没有磷的释放和浓度不是从任何不同好氧处理2（ 图2）。进行1年以下明矾在Spring Lake湖范围内的应用程序中的沉积物柱培养显示，该治疗是减少沉积物磷释放高效，与18（ 图3A），缺氧和好氧处理之间相似的释放速率。当重复实验后5年明矾处理，总磷的释放仍比治疗前显着降低，但显着高于测1次一年后的治疗，暗示疗效明矾19（ 图3B）略有下降。 <img alt="图1" fo:content-width="6in" fo:src="/files/ftp_upload/51617/51617fig1highres.jpg" src="/files/ftp_upload/51617/51617fig1.jpg" /> 图1。总磷（TP）浓度（毫克/升）时从蒙娜丽莎湖，密歇根采集沉积物岩心的实验室孵化测量，在此期间，弹簧（A），夏季（B）和秋季（C）4总磷测定水中覆沉积物岩芯从4湖遗址在20 -至28天的潜伏期。在图例中字母是指氧化还原状态（A =缺氧处理，O =好氧处理）;数是指复制数（1-3）。注意：在不同季节的y轴的不同尺度。 <a href="https://www.jove.com/files/ftp_upload/51617/51617fig1highres.jpg" target="_blank">点击这里查看大图。</a> <table border="0" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always" width="329"><tbody><tr><td>季节</td><td>现场</td><td>缺氧通量， 毫克P / 平方米 /天</td><td>好氧通量， 毫克P / 平方米 /天</td></tr><tr><td rowspan="4">春天</td><td> 1 </td><td> 2.77±1.53 </td><td> 0.25±0.01 </td></tr><tr><td> 2 </td><td> 2.82±0.83 </td><td> 0.26±0.23 </td></tr><tr><td> 3 </td><td> 0.80＆＃177; 0.07 </td><td> 0.17±0.07 </td></tr><tr><td> 4 </td><td> 1.15±0.71 </td><td> 0.12±0.04 </td></tr><tr><td rowspan="4">夏天</td><td> 1 </td><td> 7.06±2.57 </td><td> 0.46±0.24 </td></tr><tr><td> 2 </td><td> 9.27±5.99 </td><td> 1.36±0.73 </td></tr><tr><td> 3 </td><td> 15.56±1.00 </td><td> 0.90±0.29 </td></tr><tr><td> 4 </td><td> 13.63±1.82 </td><td> 0.59±0.41 </td></tr><tr><td rowspan="4">下降</td><td> 1 </td><td> 4.48±1.56 </td><td> -0.66±0.22 </td></tr><tr><td> 2 </td><td> 2.87±0.97 </td><td> -1.14±0.93 </td></tr><tr><td> 3 </td><td> 3.10±4.08 </td><td> 0.51±0.13 </td></tr><tr><td> 4 </td><td> 6.46±4.66 </td><td> -0.79±0.23 </td></tr></tbody></table> 表1。平均（±标准差）最大<html>表观TP通量在自Mona湖，密歇根收集沉积物核（毫克P / m 2 /天），以及缺氧和好氧条件4下培养。光通量由在TP浓度随时间的变化， 如图1所示来计算。 <table border="0" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always" width="308"><tbody><tr><td>季节</td><td>内部P 负载，T </td><td>外部P 负载，T </td><td>内部负载 贡献，％ </td></tr><tr><td>春天</td><td> 0.055 </td><td> 0.557 </td><td> 9.0％ </td></tr><tr><td>夏天</td><td> 2.272 </td><td> 0.862 </td><td> 72.5％ </td></tr><tr><td>下降</td><td> 1.127 </td><td> 0.242 </td><td> 82.3％ </td></tr><tr><td>冬天</td><td> 0.000 </td><td></td><td></td></tr><tr><td>全年</td><td> 3.454 </td><td></td><td></td></tr></tbody></table>内容“&gt; 表2。年度和季节性内部P负荷估计（吨，t）的对莫纳湖，密歇根州，基于最大表观TP通量4（在表1中示出）来计算。季节性内部P负荷估计进行比较，以外部P负荷预测，以确定内部的负载，以全磷负荷的贡献。 <img alt="图2" fo:content-width="5in" fo:src="/files/ftp_upload/51617/51617fig2highres.jpg" src="/files/ftp_upload/51617/51617fig2.jpg" /> 图2。平均（±SD）总磷浓度（毫克/升）时从春天湖，密歇根州，采集沉积物岩芯实验室孵化测量和实验用硫酸铝（明矾），好氧和厌氧条件下2处理。总磷测定水体中上层沉积物岩心超过20天的潜伏期。这个数字已经被修改斯坦曼等 2所转载许可，ASA，综援，SSSA。 <a href="https://www.jove.com/files/ftp_upload/51617/51617fig2highres.jpg" target="_blank">点击这里查看大图。</a> <img alt="图3" fo:content-width="5in" fo:src="/files/ftp_upload/51617/51617fig3highres.jpg" src="/files/ftp_upload/51617/51617fig3.jpg" /> 图3。平均（±SD）总磷浓度（毫克/升），在1年后19后（B）明矾的湖泊广阔的应用18（A）和5年从春天湖，密歇根采集沉积物岩芯实验室孵化测定。沉积物芯经受好氧和厌氧处理和上覆水体取样进行总磷浓度超过22日（ 一 ）至25日（二）孵化。这个数字已经被修改斯坦曼等[18];板A和斯坦曼等[19]; ​​B组</strong&gt;的信息。经许可转载，ASA，综援，SSSA。 <a href="https://www.jove.com/files/ftp_upload/51617/51617fig3highres.jpg" target="_blank">点击这里查看大图。</a>

Watch this Scientific Journal Video about Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading at JoVE.com

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

湖泊富营养化是水的质量问题在全球，需要确定和控制营养源的关键。磷释放速率沉积物岩心实验室测定是判断内部磷负荷的作用和指导管理决策有价值的方法。

实验室确定的磷通量湖泊沉积物作为内部磷载入一个测量

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

laboratory-determined-phosphorus-flux-from-lake-sediments-as-measure

Research

JoVE Journal

Environment

17.2K 次观看.  Grand Valley State University. 湖泊富营养化是水的质量问题在全球，需要确定和控制营养源的关键。磷释放速率沉积物岩心实验室测定是判断内部磷负荷的作用和指导管理决策有价值的方法。 

视频: Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

在使用高通量微孔板测定水，土壤，沉积物和微生物测定胞外酶活性的

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

科研

环境科学

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey

A technique for laboratory estimation of net trophic transfer efficiency (&#947;) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from their prey is described herein. During a 135-day laboratory experiment, we fed bloater (Coregonus hoyi) that had been caught in Lake Michigan to lake trout (Salvelinus namaycush) kept in eight laboratory tanks. Bloater is a natural prey for lake trout. In four of the tanks, a relatively high flow rate was used to ensure relatively high activity by the lake trout, whereas a low flow rate was used in the other four tanks, allowing for low lake trout activity. On a tank-by-tank basis, the amount of food eaten by the lake trout on each day of the experiment was recorded. Each lake trout was weighed at the start and end of the experiment. Four to nine lake trout from each of the eight tanks were sacrificed at the start of the experiment, and all 10 lake trout remaining in each of the tanks were euthanized at the end of the experiment. We determined concentrations of 75 PCB congeners in the lake trout at the start of the experiment, in the lake trout at the end of the experiment, and in bloaters fed to the lake trout during the experiment. Based on these measurements, &#947; was calculated for each of 75 PCB congeners in each of the eight tanks. Mean &#947; was calculated for each of the 75 PCB congeners for both active and inactive lake trout. Because the experiment was replicated in eight tanks, the standard error about mean &#947; could be estimated. Results from this type of experiment are useful in risk assessment models to predict future risk to humans and wildlife eating contaminated fish under various scenarios of environmental contamination.

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

A technique for laboratory estimation of net trophic transfer efficiency of polychlorinated biphenyl (PCB) congeners to piscivorous fish from their prey is presented. To maximize applicability of the laboratory results to the field, the piscivorous fish should be fed prey fish that are typically eaten in the field.

多氯联苯同系物净营养转移效率湖鳟鱼实验室估计（<em&gt;红点鲑namaycush</em&gt;），从它的猎物

A technique for laboratory estimation of net trophic transfer efficiency (&#947;) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from ...

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

从农业土壤使用静态钱伯斯温室气体流量测量

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. 
This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Microbial sulfate reduction is a process of great importance in environmental biotechnology. The success of the sulfidogenic reactors depends among other factors on the microbial composition of the sludge. Here, we present a protocol to develop sulfidogenic sludge from hydrothermal vents sediments in a UASB reactor for reductive dechlorination purposes.

Sulfidogenic污泥海洋沉积物和三氯乙烯减少在上流式厌氧污泥床反应器开发

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate ...

Simultaneous DNA-RNA Extraction from Coastal Sediments and Quantification of 16S rRNA Genes and Transcripts by Real-time PCR

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of taxonomic and functional groups in environmental samples. Used in combination with a reverse transcriptase reaction (RT-q-PCR), it can also be employed to quantify gene transcripts. q-PCR makes use of highly sensitive fluorescent detection chemistries that allow quantification of PCR amplicons during the exponential phase of the reaction. Therefore, the biases associated with &#39;end-point&#39; PCR detected in the plateau phase of the PCR reaction are avoided. A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. First, a method for the co-extraction of DNA and RNA from coastal sediments, including the additional steps required for the preparation of DNA-free RNA, is outlined. Second, a step-by-step guide for the quantification of 16S rRNA genes and transcripts from the extracted nucleic acids via q-PCR and RT-q-PCR is outlined. This includes details for the construction of DNA and RNA standard curves. Key considerations for the use of RT-q-PCR assays in microbial ecology are included.

A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. The methodology includes the co-extraction of DNA and RNA; preparation of DNA-free RNA; and 16S rRNA gene and transcript quantification via RT-q-PCR, including standard curve construction.

从海岸沉积物和16S量化的rRNA基因和转录同时DNA-RNA提取采用Real-time PCR检测

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of ...

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil (&#34;hexane algal oil&#34;) containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product.

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

Detailed methods are presented for the production of biodiesel along with the co-isolation of alkenones as valuable coproducts from commercial Isochrysis microalgae.

实验协议生产生物柴油与饱和酮的分离从商业余积<em&gt;等鞭金藻</em&gt;藻类生物量

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. ...

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

对水生生命值评价悬浮泥沙影响的流通系统曝光

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and screening for the selection of a fast-acting, highly virulent entomopathogenic fungus are important steps. Entomopathogenic fungi, such as Metarhizium, Beauveria, and Nomurea, which act by contact, are better suited than Bacillus thuringiensis or nucleopolyhedrosis virus (NPV), which must be ingested by the insect pest. In the present work, we isolated 68 Metarhizium strains from infected insects using a soil dilution and bait method. The isolates were identified by the amplification and sequencing of the ITS1-5.8S-ITS2 and 26S rDNA region. The most virulent strain of Metarhizium anisopliae was selected based on the median lethal concentration (LC50) and time (LT50) obtained in insect bioassays against III-instar larvae of Helicoverpa armigera. The mass production of spores by the selected strain was carried out with solid-state fermentation (SSF) using rice as a substrate for 14 days. Spores were extracted from the sporulated biomass using 0.1% tween-80, and different formulations of the spores were prepared. Field trials of the formulations for the control of an H. armigera infestation in pigeon peas were carried out by randomized block design. The infestation control levels obtained with oil and aqueous formulations (78.0% and 70.9%, respectively) were better than the 63.4% obtained with chemical pesticide.

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

Here, we report the different stages involved in the knowledge-based development of an effective mycoinsecticide, including the isolation, identification, screening, and selection of the "best-fit" entomopathogenic fungus, Metarhizium anisopliae, for the control of insect pests in agriculture.

的发展<em&gt; Metarhizium anisopliae</em&gt;作为防腐剂：从隔离到现场表现

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and ...

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and organiclastic sulfate reduction (OSR) in marine sediments. However, unravelling the complex pyritization sequence is a challenge because of the coexistence of different sequentially formed pyrite phases. This manuscript describes a sample preparation procedure that enables the use of secondary ion mass spectroscopy (SIMS) to obtain in situ &#948;34S values of various pyrite generations. This allows researchers to constrain how SO4-AOM affects pyritization in methane-bearing sediments. SIMS analysis revealed an extreme range in &#948;34S values, spanning from -41.6 to +114.8&#8240;, which is much wider than the range of &#948;34S values obtained by the traditional bulk sulfur isotope analysis of the same samples. Pyrite in the shallow sediment mainly consists of 34S-depleted framboids, suggesting early diagenetic formation by OSR. Deeper in the sediment, more pyrite occurs as overgrowths and euhedral crystals, which display much higher SIMS &#948;34S values than the framboids. Such 34S-enriched pyrite is related to enhanced SO4-AOM at the sulfate-methane transition zone, postdating OSR. High-resolution in situ SIMS sulfur isotope analyses allow for the reconstruction of the pyritization processes, which cannot be resolved by bulk sulfur isotope analysis.

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS

Analyses of the sulfur isotopic composition (&#948;34S) of pyrite from methane-bearing sediments have typically focused on bulk samples. Here, we applied secondary ion mass spectroscopy to analyze the &#948;34S values of various pyrite generations to understand the diagenetic history of pyritization.

原位含甲烷沉积物中自黄铁矿的制备及应用模拟器硫同位素分析

Different sulfur isotope compositions of authigenic pyrite typically result from the sulfate-driven anaerobic oxidation of methane (SO4-AOM) and ...

Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric hydroxide (GFH), with little effort and high reliability. The phosphonate, e.g., nitrilotrimethylphosphonic acid (NTMP), is brought into contact with the GFH in a rotator in a solution buffered by an organic acid (e.g., acetic acid) or Good buffer (e.g., 2-(N-morpholino)ethanesulfonic acid) [MES] and N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid [CAPSO]) in a concentration of 10 mM for a specific time in 50 mL centrifuge tubes. Subsequently, after membrane filtration (0.45 &#181;m pore size), the total phosphorus (total P) concentration is measured using a specifically developed determination method (ISOmini). This method is a modification and simplification of the ISO 6878 method: a 4 mL sample is mixed with H2SO4 and K2S2O8 in a screw cap vial, heated to 148-150 &#176;C for 1 h and then mixed with NaOH, ascorbic acid and acidified molybdate with antimony(III) (final volume of 10 mL) to produce a blue complex. The color intensity, which is linearly proportional to the phosphorus concentration, is measured spectrophotometrically (880 nm). It is demonstrated that the buffer concentration used has no significant effect on the adsorption of phosphonate between pH 4 and 12. The buffers, therefore, do not compete with the phosphonate for adsorption sites. Furthermore, the relatively high concentration of the buffer requires a higher dosage concentration of oxidizing agent (K2S2O8) for digestion than that specified in ISO 6878, which, together with the NaOH dosage, is matched to each buffer. Despite the simplification, the ISOmini method does not lose any of its accuracy compared to the standardized method.

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric hydroxide, with little effort and high reliability. In a buffered solution, the phosphonate is brought into contact with the adsorbent using a rotator and then analyzed via a miniaturized phosphorus determination method.

用小型化磷测定法测定膦酸在粒状氢氧化铁上吸附的优化方法

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric ...