马克诺德霍夫协助管道连接的设计和实施。艾伦司徒卢威帮助选择和购买二手设备。

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作者什么都没有透露。

在寒武纪海洋微生物群落受到管制，或修改为，他们的活动的结果和当时的地球化学条件。在解释BIF的起源，研究人员推断一般微生物的基础上，沉积或BIF的地球化学特征， 例如 ，史密斯等人 23和约翰逊等人 24的存在或活动。现代生物在有地球化学类似物古环境现代环境的研究也是一个有价值的方法， 例如，克罗等人 11和Koeksoy 等<sup...

寒武纪（4.6到0.541戈瑞前）大气经历了光合作用产生的氧逐渐积聚（O 2），也许在所谓的"大氧化事件"（GOE）阶跃变化约2.4戈瑞打断以前，又在新元古代（1至0.541戈瑞前）作为大气中的O 2走近现代化水平1。蓝藻能够氧光合作用2的第一生物的进化残余。地球化学证据和模拟研究支持沿岸浅水环境中窝藏蓝藻或能够氧光合作用或含氧的光养生物的活跃的社区，产生以下主要缺氧气氛3-5海洋表面局部氧绿洲的作用。 条状铁层的海水整个寒武纪点的铁沉积（内建函数）（II）铁（Fe（II））作为一个主要的地球化学Ç海水onstituent，至少在当地，他们的沉积过程。一些最大的BIF都是深水沉积，形成了大陆架和斜坡。铁沉积量为与主要大陆（ 即 ，风化）源的质量平衡的观点来看是不相容的。因此，大部分的铁必须从镁铁质或铁质海底地壳6热液蚀变提供。铁的速率的估计沉积沿海环境的外侧是通过上升流7供给到海洋表面用铁（Ⅱ）相一致。为了使铁在上涌电流被输送，必须已存在于缩小，移动的形式 - 的Fe（Ⅱ）。在BIF保存铁的平均氧化态为2.4 8和它一般认为BIF保留铁沉积的Fe（Ⅲ），上升流的Fe时（II）被氧化，可能是由氧形成。因此，探索沿坡environme潜在的Fe（II）氧化机制NTS重要的是要了解BIF如何形成的。此外，海洋沉积物成品地球化学特征已经确定了铁质的条件，其中的Fe（II）是目前在缺氧水柱，是整个前寒武纪海洋的持续性特征，可能不被限于时间和地点其中，BIF沉积9。因此，至少有两个十亿多年的地球历史，在浅海的Fe（II）和O 2之间的氧化还原界面有可能司空见惯。 许多研究利用现代的网站，是前寒武纪海洋的不同功能的化学和/或生物类似物。一个很好的例子是铁锈色的湖泊，铁（II）是稳定的，并出现在阳光照射的地表水，而光合活性（包括蓝细菌）检测10-13。这些研究结果提供洞察到富氧到缺氧/ FER的地球化学和微生物的特性ruginous chemocline。然而，这些位点通常在物理上与小垂直混合14，而不是在一个上升流系统中发生的化学接口分层，并且被认为是支持最氧气生产前寒武纪时间4。 一个自然的模拟探索海洋的氧气绿洲发展的缺氧气氛下，并在阳光照射面水柱的Fe（II）丰富的上涌系统不可用现代的地球上。因此，需要能够模拟铁质上升流区并且还支持蓝藻和photoferrotrophs生长的实验室系统。代表前寒武纪海水的理解和微生物过程的识别及其与上涌水介质的互动促进了理解，并可以以充分了解古代地球上独特的生物地球化学过程补充从岩石记录获得的信息。 </p&gt; 为此目的，一个实验室规模的柱的目的是在其中的Fe（II）的富含海水培养基（pH为中性的）泵入塔的底部，并从顶部抽出。光照在顶部设置来创建支持蓝藻的生长在顶端3cm的宽4厘米"透光区"。天然环境通常分层，通过理化梯度，如盐度或温度稳定。为了稳定在一个实验室规模的水柱，塔筒中填充的多孔玻璃珠基质，有助于保持成立，实验过程中形成的地球化学模式。连续的 N 2 / CO 2气体流量施加到冲洗塔的顶部空间，以维持缺氧气氛反射之前GOE 15的海洋。 （II）Fe的恒定通量成立后，蓝藻在整个柱接种，和它们的growth的通过细胞计数通过取样口取出的样品进行监测。氧气是通过将氧敏感光极箔上柱筒和测量的内壁用的光纤从塔外进行原位监测。水溶液的Fe形态通过除去样本深度分辨水平取样端口量化并与铁试剂法进行分析。非生物控制实验，结果证明证明的概念 - ，古水柱实验室规模的模拟，从大气中分离保持，是可以实现的。蓝藻生长和产生的氧，和Fe（II）和氧之间的反应是可解析的。这里，对于设计，制备，装配，执行和这样的列的采样的方法被提出，以结果一起从塔84小时运行，同时用海洋蓝细菌聚球藻接种。 7002。

<table><tbody><tr><td>Widdel flask (5 L)</td><td>Ochs</td><td>110015</td><td>labor-ochs.de</td></tr><tr><td>Glass bottles (5 L)</td><td>Rotilabo</td><td>Y682.1</td><td>carlroth.com</td></tr><tr><td>Glass pipettes (5 ml)</td><td></td><td>51714</td><td>labor-ochs.de</td></tr><tr><td>0.22 &amp;micro;m Steritop filter unit (0.22&amp;nbsp;&amp;micro;m Polyethersulfone membrane)</td><td>Millipore</td><td>X337.1</td><td>carlroth.com</td></tr><tr><td>Aluminum foil</td><td></td><td></td><td></td></tr><tr><td>Sterile Luer Lock glass syringe, filled with cotton</td><td></td><td>C681.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock stainless steel needles (150 mm, 1.0&amp;nbsp;mm ID)</td><td></td><td>201015</td><td>labor-ochs.de</td></tr><tr><td>NaCl</td><td>Sigma</td><td>433209</td><td>sigmaaldrich.com</td></tr><tr><td>MgSO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma</td><td>208094</td><td>sigmaaldrich.com</td></tr><tr><td>CaCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma</td><td>C4901</td><td>sigmaaldrich.com</td></tr><tr><td>NH&lt;sub&gt;4&lt;/sub&gt;Cl</td><td>Sigma</td><td>A9434</td><td>sigmaaldrich.com</td></tr><tr><td>KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma</td><td>P5655</td><td>sigmaaldrich.com</td></tr><tr><td>KBr</td><td>Sigma</td><td>P3691</td><td>sigmaaldrich.com</td></tr><tr><td>KCl</td><td>Sigma</td><td>P9541</td><td>sigmaaldrich.com</td></tr><tr><td>Glass cylinder</td><td></td><td>Y310.1</td><td>carlroth.com</td></tr><tr><td>Glass wool</td><td></td><td>7377.2</td><td>carlroth.com</td></tr><tr><td>Glass beads (&amp;oslash; 0.55 - 0.7&amp;nbsp;mm)</td><td></td><td>11079105</td><td>biospec.com</td></tr><tr><td>Butyl rubber stopper (&amp;oslash; 1.2 cm)</td><td></td><td>271024</td><td>labor-ochs.de</td></tr><tr><td>Petri Dish, glass (&amp;oslash; 8.0&amp;nbsp;cm)</td><td></td><td>T939.1</td><td>carlroth.com</td></tr><tr><td>Polymers glue</td><td></td><td>OTTOSEAL S68</td><td>adchem.de</td></tr><tr><td>Optical oxygen sensor foil (for oxygen analysis, see below)</td><td></td><td>&amp;ndash; on request &amp;ndash;</td><td>presens.de</td></tr><tr><td>Rubber tubing (35 mm, 7&amp;nbsp;mm ID)</td><td></td><td>770350</td><td>labor-ochs.de</td></tr><tr><td>Luer Lock tube connector (3.0 mm, Luer lock male = LLM)</td><td></td><td>P343.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock tube connector (3.0 mm, Luer lock female = LLF)</td><td></td><td>P335.1</td><td>carlroth.com</td></tr><tr><td>Rubber tubing (25 mm, 0.72 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Rubber tubing (50 mm, 7&amp;nbsp;mm ID)</td><td></td><td>770350</td><td>labor-ochs.de</td></tr><tr><td>Luer Lock stainless steel needle (150 mm, 1.0 mm ID)</td><td></td><td>201015</td><td>labor-ochs.de</td></tr><tr><td>Luer Lock glass syringe (10 ml)</td><td></td><td>C680.1</td><td>carlroth.com</td></tr><tr><td>Loose cotton&amp;nbsp;</td><td></td><td>&amp;ndash;</td><td></td></tr><tr><td>Butyl rubber stopper (&amp;oslash; 1.75 cm)</td><td></td><td>271050</td><td>labor-ochs.de</td></tr><tr><td>Stainless steel needle (40 mm, 1.0&amp;nbsp;mm ID)</td><td>Sterican</td><td>4665120</td><td>bbraun.de</td></tr><tr><td>Luer Lock stainless steel needle (150 mm, 1.5 mm ID)</td><td></td><td>201520</td><td>labor-ochs.de</td></tr><tr><td>position: Luer Lock female connector part at C.7</td><td></td><td></td><td></td></tr><tr><td>Polymers glue</td><td></td><td>OTTOSEAL S68</td><td>adchem.de</td></tr><tr><td>Stainless steel needle (120 mm, 0.7 mm ID)</td><td>Sterican</td><td>4665643</td><td>bbraun.de</td></tr><tr><td>Rubber tubing (40 mm, 0.74 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Heat shrink tubing (35&amp;nbsp;mm, 3 mm ID shrunk)</td><td></td><td>541458 - 62</td><td>conrad.de</td></tr><tr><td>Tube clamp</td><td></td><td>STHC-C-500-4</td><td>tekproducts.com</td></tr><tr><td>Luer Lock tube connector (1.0 mm, LLF)</td><td></td><td>P334.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock plastic cap (LLM)</td><td></td><td>CT69.1</td><td>carlroth.com</td></tr><tr><td>Glass bottle (5 L)</td><td>Rotilabo</td><td>Y682.1</td><td>carlroth.com</td></tr><tr><td>Butyl rubber stopper (for GL45)</td><td></td><td>444704</td><td>labor-ochs.de</td></tr><tr><td>Stainless steel capillary (300 mm, 0.74 mm ID)</td><td></td><td>56736</td><td>sigmaaldrich.com</td></tr><tr><td>Stainless steel capillary (50 mm, 0.74 mm ID)</td><td></td><td>56737</td><td>sigmaaldrich.com</td></tr><tr><td>Shrink tubing (35 mm, 3&amp;nbsp;mm ID shrunk)</td><td></td><td>541458 - 62</td><td>conrad.de</td></tr><tr><td>Rubber tubing (100 mm, 0.74 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Luer Lock tube connector (1.0 mm, LLF)</td><td></td><td>P334.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock glass syringe (10 ml)</td><td></td><td>C680.1</td><td>carlroth.com</td></tr><tr><td>Loose cotton&amp;nbsp;</td><td></td><td>&amp;ndash;</td><td></td></tr><tr><td>Butyl rubber stopper (&amp;oslash; 1.75 cm)</td><td></td><td>271050</td><td>labor-ochs.de</td></tr><tr><td>Stainless Steel needle (40 mm, 0.8&amp;nbsp;mm ID)</td><td>Sterican</td><td>4657519</td><td>bbraun.de</td></tr><tr><td>Luer lock glass syringe (5 ml)</td><td></td><td>C679.1</td><td>carlroth.com</td></tr><tr><td>Butyl rubber stopper (&amp;oslash; 1.75 mm)</td><td></td><td>271050</td><td>labor-ochs.de</td></tr><tr><td>Rubber tubing (40 mm, 0.74 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Glass bottle (2 L)</td><td>Rotilabo</td><td>X716.1</td><td>carlroth.com</td></tr><tr><td>Butyl rubber stopper (for GL45)</td><td></td><td>444704</td><td>labor-ochs.de</td></tr><tr><td>Stainless steel capillary (50 mm, 0.74 mm ID)</td><td></td><td>56736</td><td>sigmaaldrich.com</td></tr><tr><td>Rubber tubing (30 mm x 0.74 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Rubber tubing (100 mm x 0.74 mm ID)</td><td></td><td>2600185</td><td>newageindustries.com</td></tr><tr><td>Luer Lock tube connector (1.0 mm, LLF)</td><td></td><td>P334.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock 3-way connector (LLF, 2x LLM)</td><td></td><td>6134</td><td>cadenceinc.com</td></tr><tr><td>Light source</td><td>Samsung</td><td>SI-P8V151DB1US</td><td>samsung.com</td></tr><tr><td>Peristalic pump</td><td>Ismatec</td><td>EW-78017-35</td><td>coleparmer.com</td></tr><tr><td>Pumping tubing (0.89&amp;nbsp;mm ID)</td><td></td><td>EW-97628-26</td><td>coleparmer.com</td></tr><tr><td>Stainless steel capillary (200 mm, 0.74 mm ID)</td><td></td><td>56736</td><td>sigmaaldrich.com</td></tr><tr><td>Stainless steel capillary (400 mm, 0.74 mm ID)</td><td></td><td>56737</td><td>sigmaaldrich.com</td></tr><tr><td>Supel-Inert Foil (Tedlar - PFC) gas pack (10 L)</td><td></td><td>30240-U</td><td>sigmaaldrich.com</td></tr><tr><td>Rubber tube (30 mm, 6&amp;nbsp;mm ID)</td><td></td><td>770300</td><td>labor-ochs.de</td></tr><tr><td>Luer Lock tube connector (3.0 mm, LLM)</td><td></td><td>P343.1</td><td>carlroth.com</td></tr><tr><td>Luer Lock tube connector (3.0 mm, LLF)</td><td></td><td>P335.1</td><td>carlroth.com</td></tr><tr><td>Gas-tight syringe (20&amp;nbsp;ml)</td><td></td><td>C681.1</td><td>carlroth.com</td></tr><tr><td>Bunsen burner</td><td></td><td>&amp;ndash;</td><td></td></tr><tr><td>Fiber optic oxygen meter for oxygen quantification</td><td>Presens</td><td>TR-FB-10-01</td><td>presens.de</td></tr><tr><td>Vacuum pump</td><td></td><td>&amp;ndash;</td><td></td></tr><tr><td>Silicone glue for oxygen optodes</td><td>Presens</td><td>PS1</td><td>presens.de</td></tr></tbody></table>

laboratory simulation of an iron(ii)-rich precambrian marine upwelling system to explore the growth of photosynthetic bacteria

对于一些前寒武纪条状铁层（BIF）的沉积的常规概念上的假设进行了二价铁的[Fe（Ⅱ）〕从寒武纪海洋热液源上升流是由分子氧氧化[O 2]由蓝藻生产。最古老的BIF，在约2.4十亿年（戈瑞）前大氧化事件（GOE）之前沉积，可以通过铁（II）的直接氧化由缺氧条件下不产氧photoferrotrophs已经形成。至于测试，根据不同的生物情景发展地球化学和矿物学图案的方法，我们设计了一个长40厘米的垂直流过柱来模拟海洋富含系统上涌的代表远古海洋上的实验室规模缺氧的Fe（II） 。气缸中填充的多孔玻璃珠基质稳定地球化学梯度，以及铁定量的液体样品可以采取整个水柱。溶解氧检测非侵入性通过从外部光极。从从底部，从上一个独特的光梯度，以及在水体中蓝藻目前参与的Fe（II）的上涌通量生物实验，对铁的形成显示清晰证据的结果（III）矿物沉淀和chemocline发展铁之间（Ⅱ）和O 2。此列允许我们检验假设为通过模拟海洋前寒武纪的条件下培养蓝藻（和将来photoferrotrophs）形成的BIF的。此外，我们推测，我们的专栏概念允许各种化学和物理环境的模拟 - 包括浅海或湖泊沉积物。

对照实验 非生物控制实验（10天）表现出一致的低浓度的氧（O 2 &lt;0.15毫克/升）与铁（Ⅱ无显著波动）-profile整个涌水柱。析出物的形成（大概的Fe（III）（oxyhydr-）氧化物）在介质中贮存，并在整体的Fe（Ⅱ）浓度为500μM，以440μM的贯通连接的轻微下降超过10天表明一些氧气扩散橡胶制（ 例?...

Watch this Scientific Journal Video about Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria at JoVE.com

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

我们在实验室规模的垂直流通柱模拟了前寒武纪海洋铁质系统上涌。我们的目标是了解O 2和Fe（II）如何地球化学剖面演变为蓝藻产生O 2。结果表明，由于通过光合作用产生氧气的Fe（II）氧化建立chemocline的。

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

laboratory-simulation-an-iron-ii-rich-precambrian-marine-upwelling

Universidad San Sebastian

Research

JoVE Journal

Environment

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

11.7K 次观看.  University of Tuebingen. 我们在实验室规模的垂直流通柱模拟了前寒武纪海洋铁质系统上涌。我们的目标是了解O 2和Fe（II）如何地球化学剖面演变为蓝藻产生O 2。结果表明，由于通过光合作用产生氧气的Fe（II）氧化建立chemocline的。 

视频: Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated (WATER-PAM) Fluorometry

Conventional methods for experimental manipulation of microalgae have employed large volumes of culture (20 ml to 5 L), so that the culture can be subsampled throughout the experiment1&#8211;7. Subsampling of large volumes can be problematic for several reasons: 1) it causes variation in the total volume and the surface area:volume ratio of the culture during the experiment; 2) pseudo-replication (i.e., replicate samples from the same treatment flask8) is often employed rather than true replicates (i.e., sampling from replicate treatments); 3) the duration of the experiment is limited by the total volume; and 4) axenic cultures or the usual bacterial microbiota are difficult to maintain during long-term experiments as contamination commonly occurs during subsampling.
The use of microtiter plates enables 1 ml culture volumes to be used for each replicate, with up to 48 separate treatments within a 12.65 x 8.5 x 2.2 cm plate, thereby decreasing the experimental volume and allowing for extensive replication without subsampling any treatment. Additionally, this technique can be modified to fit a variety of experimental formats including: bacterial-algal co-cultures, algal physiology tests, and toxin screening9&#8211;11. Individual wells with an alga, bacterium and/or co-cultures can be sampled for numerous laboratory procedures including, but not limited to: WATER-Pulse-Amplitude-Modulated (WATER-PAM) fluorometry, microscopy, bacterial colony forming unit (cfu) counts and flow cytometry. The combination of the microtiter plate format and WATER-PAM fluorometry allows for multiple rapid measurements of photochemical yield and other photochemical parameters with low variability between samples, high reproducibility and avoids the many pitfalls of subsampling a carboy or conical flask over the course of an experiment.

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated WATER-PAM Fluorometry

The goal of this procedure is to demonstrate the reproducibility and adaptability of using a microtiter plate format for microalgal screening. This rapid screen combines WATER-Pulse-Amplitude-Modulated (WATER-PAM) fluorometry to measure photosynthetic yield as an indicator of Photosystem II (PSII) health with small volume bacterial-algal co-cultures.

小体积的生物测定评估细菌/浮游植物共培养使用水脉冲幅度调制（WATER-PAM）荧光

Conventional methods for experimental manipulation of microalgae have employed large volumes of culture (20 ml to 5 L), so that the culture can be ...

科研

环境科学

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 &#181;mol m-2 sec-1 and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Integration of microalgal cultivation with industrial flue gas will ultimately introduce heavy metals and other inorganic compounds into the growth media. This study presents a procedure used to determine the end fate and impact of heavy metals and inorganic contaminants on the growth of Nannochloropsis salina grown in photobioreactors.

重金属和微藻的产其他无机污染物的量化

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages ...

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as redox potential (Eh) and pH, but also to microbial activities that can play a direct or indirect role on speciation and/or mobility. Indeed, some bacteria can directly oxidize As(III) to As(V) or reduce As(V) to As(III). Likewise, bacteria are strongly involved in Hg cycling, either through its methylation, forming the neurotoxin monomethyl mercury, or through its reduction to elemental Hg&#176;. The fates of both As and Hg are also strongly linked to soil or aquifer composition; indeed, As and Hg can bind to organic compounds or (oxy)hydroxides, which will influence their mobility. In turn, bacterial activities such as iron (oxy)hydroxide reduction or organic matter mineralization can indirectly influence As and Hg sequestration. The presence of sulfate/sulfide can also strongly impact these particular elements through the formation of complexes such as thio-arsenates with As or metacinnabar with Hg.
Consequently, many important questions have been raised on the fate and speciation of As and Hg in the environment and how to limit their toxicity. However, due to their reactivity towards aquifer components, it is difficult to clearly dissociate the biogeochemical processes that occur and their different impacts on the fate of these TE.
To do so, we developed an original, experimental, column setup that mimics an aquifer with As- or Hg-iron-oxide rich areas versus iron depleted areas, enabling a better understanding of TE biogeochemistry in anoxic conditions. The following protocol gives step by step instructions for the column set-up either for As or Hg, as well as an example with As under iron and sulfate reducing conditions.

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

Fate and speciation of arsenic and mercury in aquifers are closely related to physio-chemical conditions and microbial activity. Here, we present an original experimental column setup that mimics an aquifer and enables a better understanding of trace element biogeochemistry in anoxic conditions. Two examples are presented, combining geochemical and microbiological approaches.

用于研究铁 (氧) 氢氧化物、微量元素和细菌之间厌氧生物地球化学相互作用的实验柱装置

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as ...

Self-standing Electrochemical Set-up to Enrich Anode-respiring Bacteria On-site

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be critical for microbial energy production and persistence in many subsurface environments, especially those lacking soluble terminal electron acceptors. While EET-capable microbes have been successfully isolated from various environments, the diversity of bacteria capable of EET is still poorly understood, especially in difficult-to-sample, low energy or extreme environments, such as many subsurface ecosystems. Here, we describe an on-site electrochemical system to enrich EET-capable bacteria using an anode as a respiratory terminal electron acceptor. This anode is connected&#160;to a cathode capable of&#160;catalyzing abiotic oxygen reduction. Comparing this approach with electrocultivation methods that use a potentiostat for poising the electrode potential, the two-electrode system does not require an external power source. We present an example of our on-site enrichment utilized in an alkaline pond at the Cedars, a terrestrial serpentinization site in Northern California. Prior attempts to cultivate mineral reducing bacteria were unsuccessful, which is likely due to the low-biomass nature of this site and/or the low relative abundance of metal reducing microbes. Prior to implementing our two-electrode enrichment, we measured the vertical profile of dissolved oxygen concentration. This allowed us to place the carbon felt anode and platinum-electroplated carbon felt cathode at depths that would support anaerobic and aerobic processes, respectively. Following on-site incubation, we further enriched the anodic electrode in the laboratory and confirmed&#160;a distinct microbial community compared to the surface-attached or biofilm communities normally observed at the Cedars. This enrichment subsequently led to the isolation of the first electrogenic microbe from the Cedars. This method of on-site microbial enrichment has the potential to greatly enhance the isolation of EET-capable bacteria from low biomass or difficult to sample habitats.

On-site microbial enrichment or in situ cultivation techniques can facilitate the isolation of difficult-to-culture microbial taxa, especially from low-biomass or geochemically extreme environments. Here, we describe an electrochemical set-up without using an external power source to enrich microbial strains that are capable of extracellular electron transport (EET).

自立电化学建立富集阳极 respiring 菌现场

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be ...

Microalgae Cultivation and Biomass Quantification in a Bench-Scale Photobioreactor with Corrosive Flue Gases

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for microalgal cultivation with temperature, pH, and gas composition and flow rate control. At bench-scale, photobioreactors are advantageous to researchers studying microalgal properties, productivity, and growth optimization. At industrial scales, photobioreactors can maintain product purity and improve production efficiency. The video describes the preparation and use of a bench-scale photobioreactor for microalgal cultivation, including the safe use of corrosive gas inputs, and details relevant biomass measurements and biomass productivity calculations. Specifically, the video illustrates microalgal culture storage and preparation for inoculation, photobioreactor assembly and sterilization, biomass concentration measurements, and a logistic model for microalgal biomass productivity with rate calculations including maximum and overall biomass productivities. Additionally, since there is growing interest in experiments to cultivate microalgae using simulated or real waste gas emissions, the video will cover the photobioreactor equipment adaptations necessary to work with corrosive gases and discuss safe sampling in such scenarios.

Bench-scale, axenic cultivation facilitates microalgal characterization and productivity optimization before subsequent process scale-up. Photobioreactors provide the necessary control for reliable and reproducible microalgal experiments and can be adapted to safely cultivate microalgae with the corrosive gases (CO2, SO2, NO2) from municipal or industrial combustion emissions.

具有腐蚀性烟气的台式光生物反应器中的微藻培养和生物量定量

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for ...

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 &#176;C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperature&#160;gradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.

The goal of this protocol is to form simulated hydrothermal chimneys via chemical garden injection experiments and introduce a thermal gradient across the inorganic precipitate membrane, using a 3D printable condenser that can be reproduced for educational purposes.

热梯度环境中早期地球热液烟囱的模拟

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the ...

Using Flexible Gold-Titanium Reaction Cells to Simulate Pressure-Dependent Microbial Activity in the Context of Subsurface Biomining

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging obstacles, including the special environmental conditions that need to be replicated, e.g., high pressure and in some cases acidic solutions. The former requires an experimental setup suitable for pressurization up to 100 bar, while the latter demands a fluid container with high chemical resistance against corrosion and unwanted chemical reactions with the container wall. To meet these conditions for an application in the field of in situ biomining, a special flexible gold-titanium reaction cell inside a rocking high-pressure reactor was used in this study. The described system allowed simulation of in situ biomining through sulfur-driven microbial iron reduction in an anoxic, pressure-controlled, highly chemically inert experimental environment. The flexible gold-titanium reaction cell can accommodate up to 100 mL of sample solution, which can be sampled at any given time point while the system maintains the desired pressure. Experiments can be performed on timescales ranging from hours to months. Assembling the high-pressure reactor system is fairly time consuming. Nevertheless, when complex and challenging (microbiological) processes occurring in the earth&#39;s deep subsurface in chemically aggressive fluids have to be investigated in the laboratory, the advantages of this system outweigh the disadvantages. The results found that even at high pressure the microbial consortium is active, but at significantly lower metabolic rates.

This protocol describes microbial experiments under elevated pressures to study in situ biomining processes. The experimental approach employs a rocking high-pressure reactor equipped with a gold-titanium reaction cell containing a microbial culture in an acidic, iron-rich medium.

使用柔性金钛反应细胞在地下生物采矿环境中模拟压力依赖微生物活性

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging ...

工程学

Construction and Setup of a Bench-scale Algal Photosynthetic Bioreactor with Temperature, Light, and pH Monitoring for Kinetic Growth Tests

The optimal design and operation of photosynthetic bioreactors (PBRs) for microalgal cultivation is essential for improving the environmental and economic performance of microalgae-based biofuel production. Models that estimate microalgal growth under different conditions can help to optimize PBR design and operation. To be effective, the growth parameters used in these models must be accurately determined. Algal growth experiments are often constrained by the dynamic nature of the culture environment, and control systems are needed to accurately determine the kinetic parameters. The first step in setting up a controlled batch experiment is live data acquisition and monitoring. This protocol outlines a process for the assembly and operation of a bench-scale photosynthetic bioreactor that can be used to conduct microalgal growth experiments. This protocol describes how to size and assemble a flat-plate, bench-scale PBR from acrylic. It also details how to configure a PBR with continuous pH, light, and temperature monitoring using a data acquisition and control unit, analog sensors, and open-source data acquisition software.

This paper describes the assembly process and operation of a bench-scale photosynthetic bioreactor that can be used, in conjunction with other methods, to estimate pertinent kinetic growth parameters. This system continuously monitors the pH, light, and temperature using sensors, a data acquisition and control unit, and open-source data acquisition software.

用于动态生长测试的温度，光照和pH监测的台式藻类光合生物反应器的构建和设置

The optimal design and operation of photosynthetic bioreactors (PBRs) for microalgal cultivation is essential for improving the environmental and economic ...

生物工程

Establishment of Microbial Eukaryotic Enrichment Cultures from a Chemically Stratified Antarctic Lake and Assessment of Carbon Fixation Potential

Lake Bonney is one of numerous permanently ice-covered lakes located in the McMurdo Dry Valleys, Antarctica. The perennial ice cover maintains a chemically stratified water column and unlike other inland bodies of water, largely prevents external input of carbon and nutrients from streams. Biota are exposed to numerous environmental stresses, including year-round severe nutrient deficiency, low temperatures, extreme shade, hypersalinity, and 24-hour darkness during the winter 1. These extreme environmental conditions limit the biota in Lake Bonney almost exclusively to microorganisms 2.
Single-celled microbial eukaryotes (called "protists") are important players in global biogeochemical cycling 3 and play important ecological roles in the cycling of carbon in the dry valley lakes, occupying both primary and tertiary roles in the aquatic food web. In the dry valley aquatic food web, protists that fix inorganic carbon (autotrophy) are the major producers of organic carbon for organotrophic organisms 4, 2. Phagotrophic or heterotrophic protists capable of ingesting bacteria and smaller protists act as the top predators in the food web 5. Last, an unknown proportion of the protist population is capable of combined mixotrophic metabolism 6, 7. Mixotrophy in protists involves the ability to combine photosynthetic capability with phagotrophic ingestion of prey microorganisms. This form of mixotrophy differs from mixotrophic metabolism in bacterial species, which generally involves uptake dissolved carbon molecules. There are currently very few protist isolates from permanently ice-capped polar lakes, and studies of protist diversity and ecology in this extreme environment have been limited 8, 4, 9, 10, 5. A better understanding of protist metabolic versatility in the simple dry valley lake food web will aid in the development of models for the role of protists in the global carbon cycle.
We employed an enrichment culture approach to isolate potentially phototrophic and mixotrophic protists from Lake Bonney. Sampling depths in the water column were chosen based on the location of primary production maxima and protist phylogenetic diversity 4, 11, as well as variability in major abiotic factors affecting protist trophic modes: shallow sampling depths are limited for major nutrients, while deeper sampling depths are limited by light availability. In addition, lake water samples were supplemented with multiple types of growth media to promote the growth of a variety of phototrophic organisms.
RubisCO catalyzes the rate limiting step in the Calvin Benson Bassham (CBB) cycle, the major pathway by which autotrophic organisms fix inorganic carbon and provide organic carbon for higher trophic levels in aquatic and terrestrial food webs 12. In this study, we applied a radioisotope assay modified for filtered samples 13 to monitor maximum carboxylase activity as a proxy for carbon fixation potential and metabolic versatility in the Lake Bonney enrichment cultures.

Microbial eukaryotes are both a source of photosynthetically-derived carbon and top predatory species in permanently ice-covered Antarctic lakes. This report describes an enrichment culture approach to isolate metabolically versatile microbial eukaryotes from the Antarctic lake, Lake Bonney, and assesses inorganic carbon fixation potential using a radioisotope assay for Ribulose-1,5-bisphophate carboxylase oxygenase (RubisCO) activity.

建立真核微生物的富集培养从化学分层南极湖和固碳潜力评估

Lake Bonney is one of numerous permanently ice-covered lakes located in the McMurdo Dry Valleys, Antarctica. The perennial ice cover maintains a ...

生物学

Operation of Laboratory Photobioreactors with Online Growth Measurements and Customizable Light Regimes

The laboratory study of microalgae can be experimentally challenging. In addition to the cultivation requirements of non-photosynthetic microorganisms, phototrophs also require illumination. Routinely, researchers seek to provide custom light supplies, i.e., vary the light intensity and time over which it is delivered. Such flexibility is difficult with standard benchtop lights. Usually, cultivation studies also require growth comparisons between experimental treatments. Frequently, growth is assessed over an extended duration, e.g., multiple times a day over a week-long trial. Manual measurements can be time-consuming and lack data resolution. Therefore, photobioreactors (PBRs) with automatic growth monitoring and customizable light supply are useful for replicated experiments with multiple treatments. The current work presents the design, construction, and operation of laboratory PBRs. The materials are easily sourced and relatively inexpensive. The design could be duplicated with moderate skill. Each structure has a footprint of ~40 cm2 and hosts three 1 L glass bottles for triplicate replication. Bottles rest upon platforms containing magnetic stirrers and are arranged vertically within a 1 m high and 15 cm diameter polyvinyl chloride (PVC) pipe. The pipe interior is lined with light-emitting diodes (LEDs). These LEDs produce continuous light intensities from 0&#8211;2400 &#181;mol photons m-2 s-1 of photosynthetically active radiation (PAR). Users design a custom lighting program. The light intensity can be adjusted each second or held constant for longer durations. Oxygen produced from photosynthesis exits each bottle via a one-way volumetric gas sensor. Software is used to record gas sensor data. The amount of oxygen produced can be correlated to biomass growth. If biomass samples are required, a syringe can be used to extract culture. The method is suited for microalgae grown with bicarbonate as the carbon source. These PBRs are valuable to a laboratory that requires replicated experiments, light regime flexibility, and continuous high-resolution growth data.

This publication describes the design of laboratory photobioreactors (PBRs) with customizable light regimes. The growth of cyanobacteria or microalgae, using bicarbonate as their carbon source, is monitored continuously by measuring volumetric oxygen production. These PBRs facilitate rapid, replicated laboratory growth comparisons with little user intervention during experiments.

通过在线生长测量和可定制的光照模式操作实验室光生物反应器

The laboratory study of microalgae can be experimentally challenging. In addition to the cultivation requirements of non-photosynthetic microorganisms, ...