EAGER: A Multi-decadal Record of Antarctic Benthos: Image Analysis to Maximize Data Utilization

南极海底生物群落的特点是海绵种类繁多（多孔动物门），长期以来被认为在定居、生长和繁殖方面呈现出极其缓慢的人口模式。该项目将分析数百张潜水员和遥控水下航行器的照片，这些照片记录了2000年至2010年发生在麦克默多湾的一个独特的、偶发的定居事件，挑战了这种缓慢增长的模式。1967年至1974年期间，在几个地点的海底放置了人工结构，但直到2004年才观察到海绵在这些结构上定居。到2010年，大约有40种海绵已经定居下来，并长得惊人的大。考虑到长期观测期（37年，1967-2004年）支持的缓慢定居和增长的范例，仅在6年的时间跨度内，这种非凡的大规模定居和快速增长是惊人的。该项目利用图像处理软件（ImageJ）获得照片中可见的海绵和其他动物的指标（估计大小、频率、覆盖百分比的线性尺寸）。它使用R进行多维标度来协调社区数据，并使用ANOSIM来测试社区数据在站点之间、时间之间和结构之间的差异。它还将使用SIMPER和排序物种丰度来区分造成任何差异的物种。这项工作的重点是南极海绵，但对大规模间歇性补充和增长的观察对于了解全球海底群落非常重要。 生态系统是由种群组成的，种群在生态学上是通过其分布和丰度来描述的。一个不太受欢迎的事实是，海绵通常占海洋群落的主导地位，但由于海绵很难研究，大多数工作人员都专注于其他群体，如珊瑚，海带或双壳类。因为大多数海绵都定居下来，生长缓慢，所以它们的生活史几乎没有人研究过。南极海底群落相对静止的假设很常见，这个项目将通过记录一个戏剧性的偶发事件来打破这种范式。最后，该项目利用了1960年代和1970年代的老样带，并将其与2010年对相同生境的广泛调查进行比较，有时是相同的完整样带线，提供了一个长期的社区变化视角。研究人员将在同行评议的期刊上发表这些结果，向公众发表演讲，并将邀请当地外展项目的学生，高中和UCSD的本科生帮助分析。

Antarctic benthic communities are characterized by many species of sponges (Phylum Porifera), long thought to exhibit extremely slow demographic patterns of settlement, growth and reproduction. This project will analyze many hundreds of diver and remotely operated underwater vehicle photographs documenting a unique, episodic settlement event that occurred between 2000 and 2010 in McMurdo Sound that challenges this paradigm of slow growth. Artificial structures were placed on the seafloor between 1967 and 1974 at several sites, but no sponges were observed to settle on these structures until 2004. By 2010 some 40 species of sponges had settled and grown to be surprisingly large. Given the paradigm of slow settlement and growth supported by the long observation period (37 years, 1967-2004), this extraordinary large-scale settlement and rapid growth over just a 6-year time span is astonishing. This project utilizes image processing software (ImageJ) to obtain metrics (linear dimensions to estimate size, frequency, percent cover) for sponges and other fauna visible in the photographs. It uses R to conduct multidimensional scaling to ordinate community data and ANOSIM to test for differences of community data among sites and times and structures. It will also use SIMPER and ranked species abundances to discriminate species responsible for any differences. This work focuses on Antarctic sponges, but the observations of massive episodic recruitment and growth are important to understanding seafloor communities worldwide. Ecosystems are composed of populations, and populations are ecologically described by their distribution and abundance. A little appreciated fact is that sponges often dominate marine communities, but because sponges are so hard to study, most workers focus on other groups such as corals, kelps, or bivalves. Because most sponges settle and grow slowly their life history is virtually unstudied. The assumption of relative stasis of the Antarctic seafloor community is common, and this project will shatter this paradigm by documenting a dramatic episodic event. Finally, the project takes advantage of old transects from the 1960s and 1970s and compares them with extensive 2010 surveys of the same habitats and sometimes the same intact transect lines, offering a long-term perspective of community change. The investigators will publish these results in peer-reviewed journals, give presentations to the general public and will involve students from local outreach programs, high schools, and undergraduates at UCSD to help with the analysis.