提交人感谢加拿大自然科学和工程研究理事会提供的资金 (05448、165831和 213411)。

1. 准备蓝藻文化
<ol><li>
利用固体培养基制备接种培养基
	<ol>
<li>获取无菌蓝藻细胞从美国类型的文化收集或巴斯德文化收集。例如, 单细胞, 海洋细长7002 是从巴斯德文化收集, 它将被称为细长以后。</li>
		<li>在含有固体介质的板上保持细长细胞 (A + 液体介质14和1.5% 琼脂15)。这些将被提到以后作为接种文化。</li>
		<li>在30–50µmol 光子 m-2 s-1,15,18的连续光线下孵化出32至2°c 的板块。</li>
		<li>重复步骤 1.1–1.3, 并将 BG-1116中的 + 介质替换为淡水蓝藻物种的步骤 1.1.2, 如Synechocystis sp 680316、17, 以后称为Synechocystis.有关第1-4 和 BG-11 介质的组成, 请参阅表。</li>
	</ol>
</li>
	<li>
准备液体培养: 每个坦克实验需要一个400毫升蓝藻文化。
	<ol>
<li>收集一个250毫升和两个1升耐热锥形瓶。</li>
		<li>用4米盐酸 (hcl) 溶液 (每瓶30毫升的 hcl 溶液) 冲洗每个烧瓶, 接着是蒸馏水。 注意: 盐酸具有腐蚀性和毒性。在使用4米 HCl 溶液时, 请确保佩戴了实验室大衣、安全护目镜和耐酸手套。在实验室水槽中执行这一步骤, 并按照当地规定处理4米 HCl 溶液</li>
		<li>用50毫升液体介质 (A + 或 BG-11) 填充250毫升烧瓶。用400毫升液体介质 (a + 或 BG-11) 和其他 1 l 烧瓶填充一个1升烧瓶, 其中有600毫升的介质 (a + 或 BG-11)。</li>
		<li>用透气的泡沫塞子封住每个烧瓶, 用锡纸盖上泡沫塞子和烧瓶颈。</li>
		<li>标签和高压釜的烧瓶在121°c 和100帕25分钟. 允许烧瓶冷却到室温。</li>
		<li>用70% 酒精消毒表面, 制备层流罩。</li>
		<li>收集电线接种回路, 本生燃烧器, 冷却50毫升液体培养基瓶 (从步骤 1.2.5) 和接种文化 (从步骤 1.1)。把这些物品放在消毒的气流罩里。</li>
		<li>使用本生燃烧器的火焰, 简单地消毒电线接种回路, 让它降温。</li>
		<li>沿接种培养的表面拖动冷却循环以收集蓝藻细胞。</li>
		<li>从250毫升瓶中取下泡沫塞子和箔帽 (不接触泡沫塞子), 通过火焰短暂传递锥形瓶的边缘。</li>
		<li>倾斜的烧瓶, 使媒体靠近烧瓶的颈部, 并插入接种环涂上细胞的瓶子。一旦循环被淹没在介质中, 搅动接种循环以移除细胞。</li>
		<li>使用本生燃烧器火焰, 除去接种回路, 重新消毒烧瓶的唇部。</li>
		<li>更换泡沫塞子和箔帽到锥形瓶 (不接触泡沫塞子)。</li>
		<li>在本生燃烧器火焰中短暂消毒接种回路。</li>
		<li>准备一个生长室 (称为生长室), 温度保持在30°c15,18和光强度是30–50µmol 光子 m-2 s-1,15,18.湿度不受主动控制。</li>
		<li>允许接种的50毫升培养在 150 rpm 的生长室进行孵化, 保持温度为30摄氏度。在搅拌过程中保持瓶子的嘴, 以控制蒸发损耗, 防止污染。</li>
		<li>允许蓝藻文化生长96小时。一个成功的文化应该出现明亮的绿色和有一个光学密度 (OD) 在750毫微米0.4–0.6。</li>
		<li>一旦文化已经充分增长, 将50毫升的文化和 1 L 烧瓶包含400毫升液体介质 (从步骤 1.2.5) 在层流罩。确保流动罩在步骤1.2.6 后灭菌。</li>
		<li>在层流罩内对两个烧瓶重复步骤1.2.10。</li>
		<li>将50毫升的文化倒入1升瓶中的400毫升培养基中, 用本生燃烧器火焰重新杀菌1升烧瓶的唇。</li>
		<li>在泡沫塞子和箔帽的地方, 附上一个无菌鼓泡装置, 由泡沫塞子、吸管、塑料管、内衬过滤器和箔盖到烧瓶口。</li>
		<li>搅动 1 L 烧瓶在 150 rpm 在30°c 与涌泉设备附有空气泵, 通过解决方案15,18在300毫升/分钟循环湿空气混合物。</li>
		<li>允许培养基在生长室内生长30摄氏度, 120–168 h。一个成功的文化应该出现明亮的绿色和有 OD750 毫微米0.4–0.6。</li>
		<li>重复步骤 1.2, 产生控制文化, 这将不会与粘土混合。</li>
		<li>使用死生物量的实验需要额外的步骤。蒸压釜1升瓶养殖60分钟, 在121摄氏度, 并允许它冷却到室温。</li>
	</ol>
</li>
</ol>2. 实验设置
<ol><li>将一个长方形的丙烯酸罐 (长度为20厘米, 宽5.1 厘米, 高度为30厘米) 放在荧光灯库的前面 (九 T8 灯泡, 至少2600流明;图 1)19。</li>
	<li>在灯和油箱之间放一层半透明的白色塑料片, 以分散光线, 透过水箱照射。这个设置是由萨瑟兰等。19
</li>
	<li>将丙烯酸罐标在高度为10厘米处, 从底座垂直测量。所有测量都应在水柱的高度进行, 以确保所有取样的一致性。</li>
	<li>将相机放在三脚架上, 在坦克前面1米处记录每个实验。视频摄像机是推荐图像可以从视频文件中提取, 并通过使用数学建模软件, 视频文件可以用来模型沉降动力学19。</li>
	<li>将黑色布放在轻型银行、坦克和照相机上, 以屏蔽外部光源的实验 (图 1)。</li>
</ol>3. 絮凝实验协议
<ol><li>收集400毫升的文化 (步骤 1.2), 一个大的毕业圆筒, 和600毫升的额外生长介质在 1 L 烧瓶 (步骤 1.2.5)。</li>
	<li>稀释400毫升培养 (第4-6 毫克/毫升的初始细胞浓度) 与额外的生长培养基 (A + 或 BG-11) 到最终体积的1升使用的毕业气缸。将此解决方案添加到亚克力罐中。</li>
	<li>准备2毫升离心管标签和放置在一个方便的位置附近的丙烯酸罐。测试50克粘土。</li>
	<li>开始视频录制。在多次实验的情况下, 一个带有实验标识符的符号可以暂时在摄像机前举行。</li>
	<li>使用吸管, 采取1毫升的样品, 并将其放置在标签离心管。使用此示例通过测量 OD750 nm值来确定初始蓝藻单元格计数。把所有样品都用三份, 以确保准确的结果。</li>
	<li>用搅拌棒将粘土 (50 克) 快速倒入水箱中, 10–15 s。</li>
	<li>启动定时器, 并采取最初的1毫升样品为智利的决心使用 P1000 吸管 (样品时间0)。</li>
	<li>在适当的时间间隔 (例如, 1 分钟, 2 分钟, 3 分钟, 4 分钟, 5 分钟, 10 分钟, 15 分钟, 30 分钟, 60 分钟, 180 分钟, 240 分钟) 进行额外的取样。</li>
	<li>实验完成后, 保存视频文件, 关闭摄像机, 并处理所有的样本以确定 (步骤 4). </li>
	<li>蒸压釜剩余的粘土/蓝藻溶液。根据蓝藻种类、当地法规和实验室策略, 使用适当的方法处理解决方案。用肥皂和水清洗水箱, 用蒸馏水冲洗, 晾干。</li>
	<li>准备一个没有粘土添加的控制实验。在同一时间点取样品。这些数据可以与其他实验数据进行比较, 以确认由于粘土絮凝而导致沉降速率提高, 而不是自然沉降的结果。</li>
	<li>如果在实验中使用死生物量, 则使用相同的实验过程。然而, 解决方案的处置程序不需要热处理。</li>
</ol>4. 样品处理和评估
<ol><li>使用从 Owttrim16修改的过程, 确定每个细胞样品中的叶绿素浓度。收集后, 在室温下使用离心, 在 1.3万 x g上将每个样品中的细胞颗粒3分钟。</li>
	<li>使用 P1000 吸管去除多余的介质, 并添加1毫升100% 甲醇 (20 °c)。将样品全速旋转1分钟, 并用重悬细胞颗粒。 注意: 甲醇是有毒和易燃的。戴上手套和安全眼镜, 保持甲醇远离点火源。</li>
	<li>将样品在-20 摄氏度孵育24小时, 以利于提取叶绿素a。</li>
	<li>孵化后, 颗粒的细胞碎片, 如4.1 所述, 转移绿色上清到一个试管使用吸管, 并把试管到分光光度计。允许样品在分光光度计中休息1分钟, 以确保样品中剩余的粘土沉淀并不会干扰测量。</li>
	<li>通过测量 665 nm 和 652 nm 的吸光度, 以及在 750 nm 上的 OD, 确定 spectrophotometrically 浓度。智利的浓度是由公式智利a = 16.29 x (665 od750)-8.54 x (652 od750) 20。浓度被用作细胞浓度的代表。此外, 一个转换因子 7.4 x 1010细胞/l = 10 克/升21可以用来计算在克的一些蓝藻物种的细胞浓度。</li>
	<li>绘制计算值与时间的数值。</li>
</ol>

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W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutual+flocculation+of+algae+and+clay:+evidence+and+implications.">Mutual flocculation of algae and clay: evidence and implications.</a> Science. 216, 63-65 (1982).</li><li>Chen, L., Men, X., Ma, M., Li, P., Jiao, Q., Lu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polysaccharide+release+by+Aphanothece+halophytica+inhibits+cyanobacteria/clay+flocculation.">Polysaccharide release by Aphanothece halophytica inhibits cyanobacteria/clay flocculation.</a> J. Phycol. 46, 417-423 (2010).</li><li>Pan, G., Zhang, M. -. M., Chen, H., Zou, H., Yan, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removal+of+cyanobacterial+blooms+in+Taihu+Lake+using+local+soils.+I.+Equilibrium+and+kinetic+screening+on+the+flocculation+of+Microcystis+aeruginosa+using+commercially+available+clays+and+minerals.">Removal of cyanobacterial blooms in Taihu Lake using local soils. I. Equilibrium and kinetic screening on the flocculation of Microcystis aeruginosa using commercially available clays and minerals.</a> Environ. Poll. 141, 195-200 (2006).</li></ol>

作者没有什么可透露的。

蓝藻细胞-粘土相互作用的絮凝反应在生态学和工程2、3、4、5、6、7 等领域引起了很大的兴趣. ,8,9,10,11,12, 然而, 这?...

利用目前的环境条件和过程来推断过去的沉积机制, 长期以来一直是沉积学的基础。虽然现代沉积类似物, 如黑海, 已被用来了解沉积的有机丰富, 细粒度矿床, 实验室的实验有可能进一步揭示页岩矿床的起源。黑色页岩成因的一个研究领域是原始地层的沉积速率和机理。传统上, 据推测, 在沉积速率、初级生产力和有机物呼吸率等环境中形成的黑色页岩, 在1、2 的沉淀物中促进有机物的保存. ,3。然而, 蓝藻和粘土絮凝的作用在很大程度上仍然不值得考虑。这种絮凝机理可以迅速沉积出富含有机物的细粒沉积物, 并且不需要低氧。考虑到这一前提, 该协议有两个目标: 1) 测量蓝藻/粘土 floccules 的沉降速率, 2) 实时可视化沉积过程。这种方法, 除了地球化学分析, 已被用来证明蓝藻/粘土絮凝实际上可能是一个重要的机制, 页岩形成1。该方法最初拟用于模拟页岩沉积时, 适用于生物和环境修复等其他学科, 其中粘土输入对细菌代谢和种群的影响需要测量。
已进行了大量的研究, 以观察蓝藻和粘土的絮凝, 以减轻有害藻类绽放2,3,4,5,6,7,8,9,10,11,12. 然而, 在测量细胞浓度的同时, 这些研究并没有应用蓝藻/粘土絮凝来模拟岩石记录的沉积。因此, 这些研究缺乏视觉成分, 这在模拟过去的沉积过程时可能是至关重要的。此外, 大多数研究都利用细胞计数 (例如, Pan等.11), 这可能是费力的。我们的方法, 最近在测量蓝藻絮凝的进展, 确定蓝藻细胞浓度的变化, 通过测量叶绿素a (智利a) 在离散时间间隔。与视觉数据进行配对是一种新的方法, 可用于推断沉积条件。所生成的图像也可用于计算杜等 al工作后的沉降速率。13. 视觉和数字数据的结合加强了结果的可靠性。此外, 我们还概述了附加的协议, 允许沉积的死生物量和粘土也被观察到。在考虑过去的沉积环境时, 这一点很重要, 那里的生物量可能发生了共生。在絮凝过程中死生物量的差异 (例如, 絮凝速率的降低) 可能会产生沉积的影响。

<table border="0" cellpadding="0" cellspacing="0" style="width:664px;" width="665">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">cyanobacteria (in this study: Synechococcus sp. PCC 7002 and Synechocystis sp. PCC 6803)</td>
			<td style="width:135px;">Pasteur Culture Collection</td>
			<td style="width:147px;">PCC 7002 or PCC 6803</td>
			<td style="width:167px;">used to inoculate the plates</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">agar</td>
			<td style="width:135px;">Thermo Scientific</td>
			<td style="width:147px;">CM0003</td>
			<td style="width:167px;">used to fill two petri dishes</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Petri plates (standard bacteriology, 100 x 15 mm)</td>
			<td style="width:135px;">Sarstedt</td>
			<td style="width:147px;">82.1473.001</td>
			<td style="width:167px;">2 required</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1 L heat resistant Erlenmeyer flask</td>
			<td style="width:135px;">Pyrex</td>
			<td style="width:147px;">4980-125</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">250 mL heat resistant Erlenmeyer flask</td>
			<td style="width:135px;">Pyrex</td>
			<td style="width:147px;">4980-250</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Nichrome inoculating loop with handle</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">14-956-103</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;">tinfoil</td>
			<td style="width:135px;">Reynolds Wrap Aluminum Foil</td>
			<td style="width:147px;">89079-067</td>
			<td style="width:167px;">50 cm required; used to cover foam stopper and neck of erlenmeyer flasks</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;">growth media (e.g. A+)</td>
			<td style="width:135px;"></td>
			<td style="width:147px;"></td>
			<td style="width:167px;">1050 mL required; produced using composition described in tables 1-4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bunsen Burner</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">S95941</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">plastic tubing</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">S504591</td>
			<td style="width:167px;">1 m required; used to create the bubbling apparatus</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;">sponge stopper</td>
			<td style="width:135px;">Jaece Industries Inc</td>
			<td style="width:147px;">14-127-40E</td>
			<td style="width:167px;">1 required; hole made in center for pipette; used for constructin the bubbling apparatus</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">acrylic sheet&#160;</td>
			<td style="width:135px;">Home Depot</td>
			<td style="width:147px;">Optix clear acrylic sheet model # MC-102S</td>
			<td style="width:167px;">1 required; used to construct acrylic tank (20 x 30 x 5.1 cm)</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">clear waterproof silicone adhesive</td>
			<td style="width:135px;">Home Depot</td>
			<td style="width:147px;">Loctite clear silicone model # 908570</td>
			<td style="width:167px;">1 required; used to construct acrylic tank (20 x 30 x 5.1 cm)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">camera or video recorder</td>
			<td style="width:135px;">Panasonic</td>
			<td style="width:147px;">HC-V770 HD camcorder</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">tripod</td>
			<td style="width:135px;">Magnus</td>
			<td style="width:147px;">VT-300</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;">black cloth</td>
			<td style="width:135px;">primomart</td>
			<td style="width:147px;">&#160;EAN 0726670162199; Part number 680254blacknappedfr</td>
			<td style="width:167px;">1 required; duvetyne light block-out cloth; approximatly 152 x 213 cm to cover tank experiment</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">heat resistant serological pipet</td>
			<td style="width:135px;">corning incorporated C708510</td>
			<td style="width:147px;">13-671-101G</td>
			<td style="width:167px;">1 required; used to create the bubbling apparatus</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">sample vials&#160;</td>
			<td style="width:135px;">Dynalon</td>
			<td style="width:147px;">S30467</td>
			<td style="width:167px;">at least 12 (will vary with time interval chosen)</td>
		</tr>
		<tr height="180">
			<td height="180" style="height:180px;">heat resistant glass pipette</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">Corning Incorporated C708510, 13-671-101G</td>
			<td style="width:167px;">1 required; used to create the bubbling apparatus; Polystyrene serological pipet would also work, but should be connected to the tubing and stopper after the rest of the apparatus is autoclaved.</td>
		</tr>
		<tr height="100">
			<td height="100" style="height:100px;">microcentrifuge</td>
			<td style="width:135px;">Eppendorf</td>
			<td style="width:147px;">22 62 120-3</td>
			<td style="width:167px;">&#160;1 required;Comparable products may be used if capable of centrifuging 1.5 -2 mL microfuge tubes at 13,000 x g</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">vortex machine (Vortex-Genie 2)</td>
			<td style="width:135px;">Scientific Industries, Inc</td>
			<td style="width:147px;">SI-0236</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="160">
			<td height="160" style="height:160px;">100% methanol</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">A412-500 SDS</td>
			<td style="width:167px;">at least 12 mL (1mL per sample) required; Caution: Flammable, toxic. Wear gloves and safety glasses. Do not use or store near ignition source. Alternate sources may be used.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">cuvettes (1.6&#160; mL, polystyrene)</td>
			<td style="width:135px;">Sarstedt</td>
			<td style="width:147px;">67.742</td>
			<td style="width:167px;">at least 12 required</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">spectrophotometer</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">222-271600</td>
			<td style="width:167px;">1 required; Pharmacia Biotech Novaspec ll could also be used.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">light bulbs</td>
			<td style="width:135px;">Home Depot</td>
			<td style="width:147px;">model # 451807; internet #205477895; store SKU #1001061538</td>
			<td style="width:167px;">6-8 bulbs required to provide light for the tank experiments</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">pipette (Pipetman Classic P1000</td>
			<td style="width:135px;">Gilson</td>
			<td style="width:147px;">F123602</td>
			<td style="width:167px;">used to collect samples</td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:216px;">37 % Hydrochloric acid</td>
			<td style="width:135px;">Sigma-Aldrich</td>
			<td style="width:147px;">258148</td>
			<td style="width:167px;">Caution: Corrosive and toxic. Wear lab coat, safety glasses and acid-resistant gloves while using. Prepared to 4 N before use by dilution into deionized water in a chemical fumehood.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Foam stopper (small)</td>
			<td style="width:135px;">Canlab</td>
			<td style="width:147px;">T 1385</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">Foam stopper (large)</td>
			<td style="width:135px;">Canlab</td>
			<td style="width:147px;">T 1387</td>
			<td style="width:167px;">Requires some intact stoppers and some with a single hole through the centre</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">30 &#176;C incubator/growth room with continuous illumination</td>
			<td style="width:135px;"></td>
			<td style="width:147px;"></td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">70 % Ethanol</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">BP8201500</td>
			<td style="width:167px;">30 mL&#160; required;Caution: Toxic and flammable. Wear lab coat and safety glasses</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">hydrophobic air filter (Midisart 2000, 0.2 &#181;m)</td>
			<td style="width:135px;">Sartorius</td>
			<td style="width:147px;">17805</td>
			<td style="width:167px;">1 required</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">clay (e.g. kaolin)</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:147px;">MFCD00062311</td>
			<td style="width:167px;">at least 50 g required</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">microfuge tubes (2 mL, polypropylene)</td>
			<td style="width:135px;">Sarstedt</td>
			<td style="width:147px;">72.695.500</td>
			<td style="width:167px;">Comparable products may be used. At least 12 (will vary with time interval chosen)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1000 &#181;L pipet tips</td>
			<td style="width:135px;">Sarstedt</td>
			<td style="width:147px;">70.762</td>
			<td style="width:167px;">1 required</td>
		</tr>
	</tbody>
</table>

determination of the settling rate of clay/cyanobacterial floccules

在很大程度上讨论了沉积细粒、富含有机沉积物的机制。具体而言, 研究了粘土颗粒与反应性、浮游蓝藻细胞相互作用对沉积记录的影响。这种相互作用是页岩沉积模型的潜在主要贡献者。在实验室设置中, 这些材料的絮凝和沉淀速率可以在受控环境中进行检查和测量。在这里, 我们详细介绍了一个测量蓝藻/粘土混合物沉降速率的协议。通过对两个样品实验的描述, 证明了这种方法: 第一次使用高岭土 (一种脱水的高岭土) 和细长7002 (一种海洋球形蓝藻), 第二次使用高岭土和Synechocystis 6803 (淡水球形蓝藻)。蓝藻文化是混合在一个专门设计的坦克设备的不同数量的粘土, 优化, 以允许连续, 实时视频和摄影记录。抽样程序是详细的, 以及收集后的协议, 以精确测量叶绿素a , 其中蓝藻细胞的浓度在悬浮可以确定。通过实验复制, 构造出显示沉降速率的剖面。

当暴露在粘土, 蓝藻细胞被带出悬浮22。在这里给出的代表性结果表明了这一点。为了确定粘土对蓝藻种群的影响, 并观察沉降速率, 进行了两次试验,细长和Synechocystis暴露在50克/升高岭土 (表 5–6, 图 2–3)。蓝藻文化按步骤1所述增长。随后, 在设置了坦克 (步骤 2) 后, 稀释后的细长文化倒?...

Watch this Scientific Journal Video about Determination of the Settling Rate of Clay/Cyanobacterial Floccules at JoVE.com

Determination of the Settling Rate of Clay/Cyanobacterial Floccules

粘土/蓝藻 Floccules 沉降速率的测定

在受控实验室环境中, 在自然环境中观察到的海洋领域内粘土和细菌细胞的相互作用和沉淀是最好的。在这里, 我们描述了一个详细的协议, 其中概述了一个新的方法来测量粘土和蓝藻 floccules 沉降率。

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction ...

determination-of-the-settling-rate-of-claycyanobacterial-floccules

Research

JoVE Journal

Environment

6.9K 次观看.  University of Alberta. 在受控实验室环境中, 在自然环境中观察到的海洋领域内粘土和细菌细胞的相互作用和沉淀是最好的。在这里, 我们描述了一个详细的协议, 其中概述了一个新的方法来测量粘土和蓝藻 floccules 沉降率。

视频: Determination of the Settling Rate of Clay/Cyanobacterial Floccules

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

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American lobsters. Recent work in exploited crustacean populations (crabs and lobsters) suggests that there are circumstances where mature females are unable to achieve their full reproductive potential due to sperm limitation. To examine this possibility in different regions of the American lobster fishery, a reliable and noninvasive method was developed for sampling large numbers of female lobsters at sea. This method involves inserting a blunt-tipped needle into the female&#39;s seminal receptacle to determine the presence or absence of a sperm plug and to withdraw a sample that can be examined for the presence of sperm. A series of control studies were conducted at the dock and in the laboratory to test the reliability of this technique. These efforts entailed sampling 294 female lobsters to confirm that the presence of a sperm plug was a reliable indicator of sperm within the receptacle and thus, mating. This paper details the methodology and the results obtained from a subset of the total females sampled. Of the 230 female lobsters sampled from George&#39;s Bank and Cape Ann, MA (size range = 71-145 mm in carapace length), 90.3% were positive for sperm. Potential explanations for the absence of sperm in some females include: immaturity (lack of physiological maturity), breakdown of the sperm plug after being used to fertilize a clutch of eggs, and lack of mating activity. The surveys indicate that this technique for examining the mating success of female lobsters is a reliable proxy that can be used in the field to document reproductive activity in natural populations.

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters Homarus americanus

Fishery-induced changes to exploited crustacean fisheries, such as the American lobster fishery, could potentially influence their reproductive dynamics, leading to a reduction in mating success. This study&#39;s goal was to develop a noninvasive method for ascertaining the mating success of female lobsters that may be physiologically or functionally mature.

一种非侵入性的方法<em&gt;原位</em&gt;交配成功的女美国龙虾​​（测定<em&gt;美洲螯龙虾</em&gt;）

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American ...

Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p &#60;0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

The goal of this protocol is to demonstrate the acceleration of the initial growth rate of plants by applying static magnetic fields with no external energy.

采用静态磁场农业植物初始增长率提高

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing ...

Determination of Inorganic Arsenic in a Wide Range of Food Matrices using Hydride Generation - Atomic Absorption Spectrometry.

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to inorganic arsenic through diet, information about distribution of arsenic species in various food types must be generated. A method, previously validated in a collaborative trial, has been applied to determine inorganic arsenic in a wide variety of food matrices, covering grains, mushrooms and food of marine origin (31 samples in total). The method is based on detection by flow injection-hydride generation-atomic absorption spectrometry of the iAs selectively extracted into chloroform after digestion of the proteins with concentrated HCl. The method is characterized by a limit of quantification of 10 &#181;g/kg dry weight, which allowed quantification of inorganic arsenic in a large amount of food matrices. Information is provided about performance scores given to results obtained with this method and which were reported by different laboratories in several proficiency tests. The percentage of satisfactory results obtained with the discussed method is higher than that of the results obtained with other analytical approaches.

The usefulness of an analytical method to determine inorganic arsenic in a wide range of food matrices is demonstrated. The method consists of selective extraction of inorganic arsenic into chloroform with a final determination by hydride generation-atomic absorption spectrometry.

用氢化物发生-原子吸收光谱法测定多种食品基质中的无机砷。

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to ...

Techniques for Investigating the Anatomy of the Ant Visual System

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye anatomy of insects. These include traditional histological techniques optimized for work on ant eyes and adapted to work in concert with other techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM). These techniques, although vastly useful, can be difficult for the novice microscopist, so great emphasis has been placed in this article on troubleshooting and optimization for different specimens. We provide information on imaging techniques for the entire specimen (photo-microscopy and SEM) and discuss their advantages and disadvantages. We highlight the technique used in determining lens diameters for the entire eye and discuss new techniques for improvement. Lastly, we discuss techniques involved in preparing samples for LM and TEM, sectioning, staining, and imaging these samples. We discuss the hurdles that one might come across when preparing samples and how best to navigate around them.

This article outlines a suite of techniques in light and electron microscopy to study the internal and external eye anatomy of insects. These include several traditional techniques optimized for work on ant eyes, detailed troubleshooting, and suggestions for optimization for different specimens and regions of interest.

蚂蚁视觉系统解剖学研究方法

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye ...

Wastewater Irrigation Impacts on Soil Hydraulic Conductivity: Coupled Field Sampling and Laboratory Determination of Saturated Hydraulic Conductivity

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. Rather than discharging treated wastewater to a stream, and thereby directly impacting the stream quality, the effluent is applied to forested and cropped land managed by the University. Concerns related to reductions in soil hydraulic conductivity occur when considering wastewater reuse. The methodology described in this manuscript, matching soil sample size with the size of the laboratory-based hydraulic conductivity measurement apparatus, provides the benefits of a relatively rapid collection of samples with the benefits of controlled laboratory boundary conditions. The results suggest that there may have been some impact of wastewater reuse on the soil&#39;s ability to transmit water at deeper depths in the depressional areas of the site. Most of the reductions in the soil hydraulic conductivity in the depressions appear to be related to the depth from which the sample was collected, and by inference, associated with the soil structural and textural differences.

Here we present a methodology which matches a soil sample size and a hydraulic conductivity measurement device to prevent the so-called wall flow along the inside of the soil container from being erroneously included in water flow measurements. Its use is demonstrated with samples collected from a wastewater irrigation site.

污水灌溉对土壤水力电导率的影响: 耦合场取样与饱和水力电导率的实验室测定

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. ...

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 ...

Sample Preparation Method of Scanning and Transmission Electron Microscope for the Appendages of Woodboring Beetle

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of the woodboring beetle, Chlorophorus caragana Xie &#38; Wang (2012), for both types of electron microscopy. The scanning electron microscopy (SEM) sample preparation protocol was based on sample chemical fixation, dehydration in a series of ethanol baths, drying, and sputter-coating. By adding Tween 20 (Polyoxyethylene sorbitan laurate) to the fixative and the wash solution, the insect body surface of woodboring beetle was washed more cleanly in SEM. This study&#39;s transmission electron microscopy (TEM) sample preparation involved a series of steps including fixation, ethanol dehydration, embedding in resin, positioning using fluorescence microscopy, sectioning, and staining. Fixative with Tween 20 enabled penetrate the insect body wall of woodboring beetle more easily than it would had been without Tween 20, and subsequently better fixed tissues and organs in the body, thus yielded clear transmission electron microscope observations of insect sensilla ultrastructures. The next step of this preparation was determining the positions of insect sensilla in the sample embedded in the resin block by using fluorescence microscopy to increase the precision of target sensilla positioning. This improved slicing accuracy.

In order to observe ultrastructure of insect sensilla, scanning and transmission electron microscopy (SEM and TEM, respectively) sample preparation protocol were presented in the study. Tween 20 was added into the fixative to avoid sample deformation in SEM. Fluorescence microscopy was helpful for improving slicing accuracy in TEM.

木钻甲虫附着物扫描和透射电子显微镜的样品制备方法

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of ...

Measurement of Aerosols Optical Thickness of the Atmosphere using the GLOBE Handheld Sun Photometer

Here, we describe the measurement of aerosol optical thickness using the GLOBE handheld sun photometer. Aerosol optical thickness (AOT) was measured at Xavier University of Louisiana (XULA, 29.96&#176; N, 90.11&#176; W and 3 m above sea level). The measurements were done at two different wavelengths, 505 nm and 625 nm. AOT measurements were done 6 times a day (7 AM, 9 AM, 11 AM, solar noon, 3 PM and 5 PM). The data shown in this paper are the monthly average AOT values taken at solar noon. During each measurement time; at least five values of the sunlight voltage V and the dark voltage Vdark are taken for each channel. The mean for these five measurements is taken as the average for that measurement time. Other meteorological data such as temperature, surface pressure, rainfall and relative humidity are also measured at the same time. The whole protocol is completed within a time span of 10&#8211;15 min. The measured AOT values at 505 nm and 625 nm are then used to extrapolate the AOT values for wavelengths 667 nm, 551 nm, 532 nm and 490 nm. The measured and extrapolated AOT values were then compared with values from the nearest AERONET station at Wave CIS site 6 (AERONET, 28.87&#176; N, 90.48&#176; W and 33 m above sea level), which is about 96 km south of XULA. In this study we tracked the annual and daily variations of AOT for a 12 month period from September 2017 to August 2018. We also compared AOT data from two independently calibrated GLOBE handheld sun photometers at the XULA site. The data show that the two instruments are in excellent agreement.

The goal of the methods presented here is to measure aerosol optical thickness of the atmosphere. The sun photometer is pointed at the sun and the largest voltage reading obtained on an in-built digital voltmeter is recorded. Atmospheric measurements such as barometric pressure and relative humidity are also performed.

用 GLOBE 手持式太阳测光仪测量大气气溶胶光学厚度

Here, we describe the measurement of aerosol optical thickness using the GLOBE handheld sun photometer. Aerosol optical thickness (AOT) was measured at ...

Impedance Pneumography for Minimally Invasive Measurement of Heart Rate in Late Stage Invertebrates

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by environmental temperature, this has the potential to alter thermal physiological performance in a variety of marine organisms. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography to understand how cardiac performance in late stage invertebrates changes under acute thermal stress. The protocol presents a minimally invasive technique that allows for real-time collection of heart rate during a temperature ramping experiment. Data are easily manipulated to generate an Arrhenius plot that is used to calculate Arrhenius break temperature (ABT), the temperature at which heart rate begins to decline with increasing temperatures. This technique can be used in a variety of late stage invertebrates (i.e., crabs, mussels, or shrimps). Although the protocol focuses solely on the impact of temperature on cardiac performance, it can be modified to understand the potential for additional stressors (e.g., hypoxia or hypercapnia) to interact with temperature to influence physiological performance. Thus, the method has potential for wide-ranging applications to further understand how marine invertebrates respond to acute changes in the environment.

Measuring heart rate during a thermal challenge provides insight into physiological responses of organisms as a consequence of acute environmental change. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography as a relatively noninvasive and nonlethal approach to measure heart rate in late stage invertebrates.

晚期无脊椎动物中心率微创测量的阻抗肺造影

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by ...