Dinoflagellates as proxy indicators of marine environmental conditions in northern and southern high latitudes

甲藻作为北部和南部高纬度地区海洋环境条件的代理指标

• 批准号: RGPIN-2014-05609
• 负责人: Rochon, André
• 金额: $ 2.19万
• 依托单位: Université du Québec à Rimouski
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611734
• 关键词: Dinoflagellates; proxy; indicators; marine; environmental

This proposal aims at studying several aspects of dinoflagellates and their cysts at various locations and timescales. Dinogflagellates are unicellular protists that are important primary producers in the World oceans. They produce a resting cyst as part of their life cycle in response to adverse conditions. The cyst is composed of a highly resistant polymer that allows them to be preserved intact for millions of years in the sediments. Dinoflagellates are notably responsible for harmful algal blooms, or "red tides", which cause chronic illness to humans, kill fish and marine mammals and cause the loss of millions of dollars in revenue to the Canadian aquaculture industry each year. They are also famous because they are easily transported in ballast tanks of ships and colonize new environments when the ballast tanks are emptied at the ship destination, often bringing toxic red tides in new areas. Despite that, their cysts constitute excellent paleo-indicators of sea surface conditions and they are used to quantitatively reconstruct sea surface conditions of the recent geological past. Here we present 7 projects that use dinoflagellates or their cysts as the main tool. One project aims at reconstructing the evolution of sea surface conditions in the Canadian Arctic, notably with respect to sea ice and primary productivity. The reconstruction focuses on the last 2000 years in order to understand how the primary productivity has changed in the recent geological past during warmer or colder climate conditions. The project also aims at looking at cysts of potentially toxic species that may have been transported in the Arctic by oceanic currents or by ship. Another projects aims at describing two new species discovered in Arctic surface sediments. A morphological description will be done, the cysts will be assigned a formal species name and their genetic code will be sequenced to help identifying them in the future. One project deals with the cysts of a toxic species in the Port of Halifax, Nova Scotia. Genetic sequencing of the cysts will be done to verify their toxicity and see if there is potential danger of toxic red tide in the area. A short sediment core will also be studied to find out if the cysts occur in that location naturally, or if they were transported from somewhere else by ships, therefore being considered as an invasive species. A similar study will take place in the Gulf of San Jorge in Argentina. There we will look at cysts in surface sediments to estimates the risks of toxic red tides, and look at short sediment cores to find out if anyone species present was transported there or if it occurs naturally. The next project consists of a highly innovative approach to study the cysts or the motile forms, or any other marine micro-organsims. We are using micro- and nano-CT-Scans, which use X rays to produce images to visualize the dinoflagellate. To our knowledge, this is the first time that such small organisms are successfully scanned with X rays. When perfected, the technique will allow observing dinoflagellates inside and out and from every angles without touching them, or any marine organism in plankton or sediment samples without having to use chemicals to process the samples and with the same precision as the most powerful microscope. And the scans produce very cool images too! Finally we will be studying the chemical composition of dinoflagellate cysts to try and find out what they are made of and why they are so resistant. If we are successful, we should be able to replicate this composition to create ultra-resistant nanomaterials. We are also planning to use the chemical composition of the cysts to find out about the environmental conditions in which they lived, therefore documenting past climates.

该建议旨在研究在各个位置和时间尺度上鞭毛藻及其囊肿的几个方面。 Dinogflagellates是单细胞生物，它们是世界海洋中重要的主要生产者。他们在不良条件下产生静息囊肿，作为其生命周期的一部分。该囊肿由高度抗性​​的聚合物组成，可在沉积物中保存数百万年的完整性。鞭毛藻特别责任有害的藻华或“红潮”，这会导致人类慢性疾病，杀死鱼类和海洋哺乳动物，并每年损失数百万美元的收入。它们之所以闻名，是因为它们很容易在船舶的压载水箱中运输，并在船目堡空倒空时将新环境定居，通常会在新地区带来有毒的红潮。尽管如此，它们的囊肿构成了海面条件的出色古探测器，它们用于定量重建最近地质过去的海面条件。在这里，我们提出了7个使用Winoflagellates或其囊肿作为主要工具的项目。一个项目旨在重建加拿大北极地区海面条件的演变，尤其是在海冰和主要生产力方面。重建的重点是过去2000年，以了解在较温暖或寒冷的气候条件下，主要生产力在最近的地质过去如何变化。该项目还旨在研究可能通过海洋电流或船舶在北极运输的潜在有毒物种的囊肿。另一个项目旨在描述在北极表面沉积物中发现的两个新物种。将进行形态学描述，囊肿将被分配一个形式的物种名称，并将对其遗传代码进行测序，以帮助将来识别它们。一个项目涉及新斯科舍省哈利法克斯港的有毒物种的囊肿。将进行囊肿的遗传测序以验证其毒性，并查看该地区有毒红潮的潜在危险。还将研究一个短的沉积物核心，以找出囊肿是否自然出现在该位置，或者是否是由船只从其他地方运输的，因此被视为入侵物种。类似的研究将在阿根廷的圣豪尔夫湾进行。在那里，我们将研究表面沉积物中的囊肿，以估计有毒红潮的风险，并查看短的沉积物核心，以找出是否存在存在的物种，还是自然发生。下一个项目包括一种高度创新的方法，用于研究囊肿或运动形式或任何其他海洋微孔线。我们使用的是微型和纳米CT扫描，它们使用X射线产生图像来可视化鞭毛藻。据我们所知，这是第一次成功扫描X射线。完善后，该技术将允许从各个角度观察到局部和从各个角度观察鞭毛，或者在浮游生物或沉积物样品中的任何海洋生物，而无需使用化学药品来处理样品，并且具有与最强大的显微镜相同的精度。扫描也产生非常酷的图像！最后，我们将研究鞭毛藻囊肿的化学组成，以尝试找出它们的构成以及为什么如此抗性。如果我们成功，我们应该能够复制这种组成以创建超耐纳米材料。我们还计划使用囊肿的化学成分来了解它们所生活的环境条件，从而记录过去的气候。