International Research Fellowship Program: Vulnerability and Resilience of Sponge Populations and their Bacterial Symbionts to Climate Change and Anthropogenic Disturbances

0853089Erwin该奖项由2009年美国复苏和再投资法案(公法111-5)资助。国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持帕特里克·M·欧文博士为期24个月的研究奖学金，与西班牙布朗斯高级研究中心和西班牙研究理事会的泽维尔·图隆博士合作。海洋生物对人为压力的短期脆弱性和长期弹性将决定水生生态系统的未来，并反过来将对人类与海洋的互动产生重大影响。人类活动的负面后果影响到几乎所有海洋生物；然而，居住在沿海环境中的固着、滤食性无脊椎动物特别容易受到影响，因为成体不能活动、集中暴露于水中的污染物以及靠近人口密集的人口。海绵是一种古老的滤食性生物，在各种海洋环境中茁壮成长，对海洋生态系统的健康运行至关重要。海绵-微生物组合代表了基础和原始的多细胞动物群体与古老的细菌谱系之间独特的共生关系，这些细菌谱系似乎是共同进化的，并经受了广泛的环境条件。微生物共生体组成的变化是海绵全叶内关系破坏的早期信号，有益细菌的丧失以及感染和寄生微生物的繁殖。相关微生物群落对宿主海绵健康的关键重要性为研究自然和人为应激源对宿主-共生体稳定性的影响以及破坏细菌共生体群落对宿主海绵适宜性的后果提供了一个理想的系统。评估单个生物和整个生态系统对日益增加的污染和气候变化的脆弱性和弹性涉及监测致死和亚致死水平的影响。致命性污染的影响在群落和物种层面进行了研究，记录了群落组成的变化，并跟踪了生物指示物种。这些反应是终极的，只有在长期接触后才能得到证实。相比之下，对污染和气候变化的亚致命反应是在细胞和分子水平上研究的，因为小剂量的污染物或温度变化可能会影响生物体的生理功能和行为，而不会杀死它们。因此，分子水平上的变化发生在经典监测和生物检测方法可以检测到的变化之前，因此分子生物标记物可以被视为污染和压力亚致死效应的早期预警系统。本研究是一项多尺度的研究项目，旨在研究地中海海绵及其共生微生物群对自然和人为应激源的生态(生长和生存)、生理(宿主-共生相互作用)和细胞(基因表达)响应。这项研究的现场部分包括对未受干扰的和经过实验遮蔽的海绵(Ircinia bunculata和I.ariablis)进行为期1.5年的监测，以评估HSP70应激蛋白基因表达的季节性变化、共生体的光合作用活性和共生体多样性，并确定共生体的自养营养在宿主海绵生长和胁迫状态中的作用。这项研究的实验室部分涉及在受控水族箱条件下将同一海绵物种暴露在重金属、杀虫剂和升高的海水温度下，以评估污染物和气候变化对微生物共生体群落结构和宿主海绵细胞应激反应的潜在影响。面对不断增加的人口和全球气候变化造成的前所未有的环境条件，解决生物对新的干扰机制的脆弱性和复原力对于保护现有生态系统和预测未来人类对自然系统的影响至关重要。

0853089ErwinThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Patrick M. Erwin to work with Dr. Xavier Turon at the Centre of Advanced Studies of Blanes and at the Spanish Research Council in Blanes, Spain.The short-term vulnerability and long-term resilience of marine organisms to anthropogenic stressors will dictate the future of aquatic ecosystems and will, in turn, have a large impact on humankind's interactions with the sea. The negative consequences of human activities affect nearly all marine organisms; however, sessile, filter-feeding invertebrates inhabiting coastal environments are especially susceptible, due to adult immobility, concentrated exposure to waterborne pollutants and proximity to dense human populations. Sponges are ancient, filter-feeding organisms that thrive in a variety of marine environments and are essential to the healthy functioning of marine ecosystems. Sponge-microbial associations represent unique symbioses between a basal and primitive multi-cellular animal group and ancient bacterial lineages that appear to have co-evolved and endured a wide range of environmental conditions. Changes in the composition of microbial symbionts are an early signal of the disruption of the relationships within the sponge holobiont, with the loss of beneficial bacteria and proliferation of infectious and parasitic microbes. The critical importance of associated microbial communities to host sponge health offers an ideal system to study the impact of natural and anthropogenic stressors on host-symbiont stability and the consequences of disrupting bacterial symbiont communities on host sponge fitness.Assessing the vulnerability and resilience of individual organisms and entire ecosystems to increasing pollution and climate shifts involves monitoring the effects of both lethal and sub-lethal levels. The effects of lethal pollution are studied at the community and species level, documenting shifts in community composition and tracking bioindicator species. These responses are ultimate and are evidenced only after prolonged exposure. In contrast, sub-lethal responses to pollution and climate change are studied at the cellular and molecular level because small doses of pollutants or temperature changes may affect the physiological functions and behavior of organisms without killing them. Thus, changes at the molecular level occur before those that can be detected by classical monitoring and bioassays so that molecular biomarkers can be considered as early warning systems for sub-lethal effects of contamination and stress.The current study is a multi-scale research project examining the ecological (growth and survival), physiological (host-symbiont interactions) and cellular (gene expression) responses of Mediterranean sponges and their symbiotic microflora to natural and anthropogenic stressors. The field component of the study involves monitoring undisturbed and experimentally shaded sponges (Ircinia fasciculata and I. variabilis) over 1.5 years to assess seasonal variability in gene expression of the hsp70 stress protein, symbiont photosynthetic activity and symbiont diversity and to determine the role of autotrophic nutrition from symbionts in host sponge growth and stress status. The laboratory component of the study involves exposing the same sponge species to heavy metals, pesticides and increased seawater temperatures under controlled aquaria conditions to assess the potential effects of pollutants and climate change on the community structure of microbial symbionts and the cellular stress responses of host sponges. In the face of increasing human populations and unprecedented environmental conditions resulting from global climate change, addressing the vulnerability and resilience of organisms to new disturbance regimes is critical to the preservation of current ecosystems and the forecasting of future anthropogenic impacts on natural systems.