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Counter-gradient Flow of Fatty Acids in Marine Food Webs Through Egg Boons

海洋食物网中脂肪酸通过蛋恩的反梯度流动

基本信息

批准号：
2023618
负责人：
Lee Fuiman
金额：
$ 51.45万
依托单位：
University of Texas at Austin
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2023618&HistoricalAwards=false
关键词：
Counter gradient Flow Fatty Acids

项目摘要

Marine animals release extremely large numbers of eggs when they spawn. Most of these eggs are eaten by animals ranging from microscopic plankton to fish. Many egg consumers are smaller than the animals that released the eggs, representing a reversal of the usual food web. The consumption of eggs provides animals with highly nutritious molecules called essential fatty acids which are very concentrated in eggs. These essential fatty acids are important for the health of animals and the health of the whole ecosystem. When marine fishes form spawning aggregations to coordinate the timing and location of spawning, they release trillions of eggs. This results in an “egg boon” – an immense but temporary concentration of highly nutritious fatty acids. This project combines field-based sampling with laboratory experiments to assess how fatty acids in the egg boons affect food webs. The project is determining whether consumption of eggs is beneficial to the condition of the egg consumers. New findings from this project are advancing the understanding of aquatic food webs and contributing to improved management of marine resources. For example, commercial harvest of fish can remove tons of fatty acids from an ecosystem by reducing egg boons and leading to cascading and unforeseen effects on those biological communities. The project is fostering the participation of women in science by substantially advancing the professional training of a female postdoctoral fellow. The project is supporting K-12 STEM education through inquiry-based and place-based programs for teachers and youth. Findings are being communicated to the public locally and nationally through participation in public lectures and contributions to the Science and the SeaTM radio program, podcast, and website.Super-abundances of eggs released in temporally and spatially discrete patches create pulsed nutritional resources for egg consumers, called “egg boons,” which are potentially important components of marine food webs. While various marine animals have been shown to consume eggs, the role of egg boons in energy transfer through food webs has received little attention. Three hypotheses are being tested: 1) egg boons provide a pathway through which essential fatty acids (EFAs) are redistributed counter to the main direction of trophic flow; 2) stores of EFAs in egg consumers increase during egg boons and remain elevated after the spawning season; and 3) egg boons are beneficial to the condition of egg consumers. The proposed research takes advantage of an annual egg boon produced by a spawning aggregation of the marine fish, red drum (Sciaenops ocellatus) near Port Aransas, Texas. In a combination of field sampling and laboratory experiments, fatty acid profiles, lipid content, and bulk stable isotope ratios are measures used to define trophic links between the egg boon and a selection of lower-trophic-level taxa. Egg boons are simulated in laboratory feeding experiments that are designed to enhance interpretation of data collected from field based sampling by comparing taxa that consume fish eggs with those that do not. A nucleic acid biomarker (RNA/DNA ratios) is being used to assess changes in condition that can be attributed to egg consumption in target taxa. In the environment, the importance and persistence of counter-gradient flow of fatty acids in the food web is being gauged through comparisons of samples taken inside and outside the spatial and temporal extent of the egg boon. The effects of egg consumption on consumers is being quantified in controlled experiments to identify dietary biomarkers of egg consumption in consumer tissues that can be applied to field samples. The proposed research examines how egg consumption redistributes EFAs within food webs and provides a context for considering potential controls and trophic bottlenecks that cannot be explained from the traditional element-limitation models. The integration of fatty acid and stable isotope approaches is expected to provide greater resolution for tracking organic matter through food webs and to advance the application of multi-tracer techniques in trophic investigations. Further, if egg boons are indeed an important nutritional subsidy to select groups of consumers, then subsequent studies investigating the energetic contribution of egg boons to secondary production in marine food webs are warranted. An analysis of how reduction or removal of egg resources through the harvest of fishes in spawning aggregations changes nutrient flow in food webs could have implications for ecosystem-based fisheries management.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海洋动物产卵时会释放大量的卵。这些卵中的大多数被从微小的浮游生物到鱼类的动物吃掉。许多吃鸡蛋的动物比放鸡蛋的动物体型小，这代表了通常食物网的逆转。食用鸡蛋为动物提供了高营养的分子，称为必需脂肪酸，这些脂肪酸在鸡蛋中非常集中。这些必需脂肪酸对于动物的健康和整个生态系统的健康非常重要。当海洋鱼类形成产卵群以协调产卵的时间和地点时，它们会释放数万亿枚卵。这导致了"鸡蛋布恩"--一种巨大但暂时的高营养脂肪酸浓缩。该项目结合了基于现场的采样和实验室实验，以评估卵群中的脂肪酸如何影响食物网。该项目正在确定食用鸡蛋是否有益于鸡蛋消费者的健康状况。该项目的新发现正在推进对水生食物网的了解，并有助于改善海洋资源的管理。例如，鱼类的商业捕捞可以通过减少卵源从生态系统中去除成吨的脂肪酸，并对这些生物群落产生级联和不可预见的影响。该项目通过大力推进一名女博士后研究员的专业培训，促进妇女参与科学。该项目通过面向教师和青年的基于调查和基于地点的计划支持K-12 STEM教育。研究结果正在通过参加公开讲座和向科学与海洋TM广播节目、播客和网站投稿的方式向当地和全国的公众传达。在时间和空间离散的斑块中释放的超丰度鸡蛋为鸡蛋消费者创造了脉冲营养资源，称为"鸡蛋恩惠"，这是海洋食物网的潜在重要组成部分。虽然各种海洋动物已经被证明消耗鸡蛋，但鸡蛋在食物网能量转移中的作用很少受到关注。三个假设正在测试中：1）卵丰提供了一个途径，通过该途径，必需脂肪酸（EFA）的营养流的主要方向相反的重新分配; 2）在蛋消费者的EFA的存储增加，在产卵季节后保持升高;和3）卵丰是有益的鸡蛋消费者的条件。这项拟议中的研究利用了德克萨斯州阿兰萨斯港附近的一种海鱼红鼓鱼（Sciaenops ocellatus）产卵聚集产生的年度卵布恩。在野外采样和实验室实验相结合，脂肪酸配置文件，脂质含量，和散装稳定同位素比值的措施，用于定义之间的营养联系的鸡蛋布恩和低营养级类群的选择。卵恩模拟实验室饲养实验，旨在提高从现场采样收集的数据的解释比较类群消耗鱼卵与那些不。一种核酸生物标志物（RNA/DNA比率）被用来评估可归因于目标分类群中鸡蛋消耗的状况变化。在环境中，通过比较蛋布恩的空间和时间范围内外的样本，正在衡量食物网中脂肪酸反梯度流动的重要性和持久性。鸡蛋消费对消费者的影响正在受控实验中进行量化，以确定可应用于现场样本的消费者组织中鸡蛋消费的饮食生物标志物。拟议的研究探讨了鸡蛋消费如何在食物网内重新分配EFA，并为考虑传统元素限制模型无法解释的潜在控制和营养瓶颈提供了背景。脂肪酸和稳定同位素方法的整合，预计将提供更大的分辨率，通过食物网跟踪有机物，并推动应用多种示踪技术在营养调查。此外，如果蛋恩确实是一个重要的营养补贴，选择消费者群体，然后随后的研究调查的精力充沛的贡献，在海洋食物网的次级生产的蛋恩是必要的。分析如何减少或删除产卵聚集的鱼类收获的鸡蛋资源改变营养流的食物网可能会对生态系统为基础的渔业管理产生影响。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。