LTREB Renewal: High-amplitude midge fluctuations and the ecosystem dynamics of Lake Myvatn, Iceland

生物体--蝗虫、旅鼠、昆虫--的戏剧性“爆发”吸引了公众对自然界的关注，部分原因是科学家们并不完全理解这些种群激增的原因。这项研究将调查冰岛梅尔瓦顿湖的蚊子，以及为什么它们的丰度在持续4-7年的不规则周期中波动超过4个数量级。从湖里出来的成年蚊子会死在岸上。在高峰期，滞留在周围荒原上的蚊子的重量相当于10头座头鲸，为捕食者和食腐动物提供食物，为植物提供营养，并为当地农业提供基础。通过综合几个种群周期的现场样本和实验结果，该项目有望对有关人口暴发的原因和后果的基本科学问题提供新的见解。该项目将吸引研究生和本科生，他们每年夏天将在Mèvatn工作，让他们接触极端生物学和教育多样性，因为他们在一个跨学科科学家小组的指导下在湖和海岸线工作。公众将通过一个正在进行的“微小的蚊子”博客了解更多关于蚊子爆发的信息。随着时间的推移，生态系统显示出巨大的变化，可以揭示稳定或破坏自然动态稳定的生态力量。该项目既包括对水生和陆地系统的长期数据收集，也包括测试特定假设的有针对性的实验。水生数据收集将在现有数据库的基础上进行建设和扩展，该数据库可以追溯到20世纪70年代。该项目增加了对许多其他变量的每周监测，包括蚊虫幼虫密度、底栖初级生产力和远洋营养物质。继续收集陆地数据，监测2008年建立的环湖断面上的蚊虫落水和节肢动物群落。一系列有针对性的实验将解决广泛的研究问题，例如(I)蚊子作为生态系统工程师所扮演的角色，改变底栖条件，使大型底栖生物枝角类比小型底栖动物物种更受青睐，(Ii)蚊虫幼虫对藻类生长的互惠作用，以及(Iii)蚊虫成虫对食肉植物开花的重要性。这些实验项目由研究生领导，作为博士论文的一部分，由本科生实习生作为独立项目领导。这种水生和陆地实验的结合，以及定期采样，将检验有关湖泊和海岸线生态系统如何联系在一起的假设。这项研究将研究湖泊生态系统的不稳定是否会导致陆地上周围生态系统的不稳定。

Dramatic 'outbreaks' of organisms - locusts, lemmings, insects - draw public attention to the natural world, in part because scientists do not completely understand the causes for these population surges. This study will investigate midges in Lake Mývatn, Iceland, and why their abundance fluctuates over 4 orders of magnitude in irregular cycles lasting 4-7 years. Adult midges that emerge from the lake die on shore. During high-midge years, the weight of midges that are deposited in the surrounding heathland is equivalent to 10 humpback whales, providing food for predators and scavengers, nutrients for plants, and the basis for local agriculture. By synthesizing results from field samples and experiments over several population cycles, this project promises new insights into fundamental scientific questions about the causes and consequences of population outbreaks. The project will engage graduate and undergraduate students who will work at Mývatn each summer, providing them exposure to extreme biology as well as to educational diversity, as they work in both the lake and on the shoreline under the tutelage of an interdisciplinary group of scientists. The public will learn more about midge outbreaks through an ongoing 'Smidge of Midge' blog.Ecosystems that show huge changes through time can reveal the ecological forces that stabilize or destabilize natural dynamics. This project involves both long-term data collection in aquatic and terrestrial systems and targeted experiments to test specific hypotheses. The aquatic data collection will build and expand on an existing database that dates back to the 1970s. The project has added weekly monitoring of many additional variables, including midge larvae density, benthic primary production, and pelagic nutrients. The collection of terrestrial data has continued with the monitoring of midge infall and arthropod communities along transects around the lake that were established in 2008. A suite of targeted experiments will address a wide range of research questions such as (i) the role that midges play as ecosystem engineers, changing benthic conditions to favor large-bodied epibenthic cladocerans over small-bodied infaunal species, (ii) the mutualistic effect that midge larvae have on algal growth, and (iii) the importance of midge adults for the flowering of carnivorous plants. These experimental projects are led by graduate students as part of their PhD theses, and by undergraduate interns as independent projects. This combination of aquatic and terrestrial experiments together with regular sampling will test hypotheses about how the lake and shoreline ecosystems are linked together. The research will examine whether the instability of the lake ecosystem could drive instability of the surrounding ecosystem on land.