Microorganisms on Burrow Walls of Infauna: Predictable or Fortuitous Occurrence?

大型底栖生物的洞穴通常是微生物活动强烈的地点，通常有大量的微生物种群。由于不同的动物区系物种在生物学上(如摄食协会、活动能力)有很大的不同，特别是在洞穴的结构和通风方面，有理由预计它们洞穴的微生物学也会有所不同。该项目将测试洞穴中微生物丰度和活性的增加是否仅仅代表环境微生物的增强，或者是否存在特定的微生物种群，这些微生物种群可以预测地出现在洞穴中，与周围的微生物群落无关。对这些复杂的微生物群落的全面评估将需要非选择性方法；将检查微生物的磷脂、酯连接脂肪酸(PLFA)，这是真细菌和真核生物膜脂的主要成分。这些PLFA已经从洞穴和周围沉积物的野外样本中提取出来，是确定微生物生物量、成分甚至生理条件的强大、区分工具。这些生化标记将被用来比较代表三个门的五个动物群物种的洞穴微生物，这些物种在六个地点采样。将使用多变量分析在种间和种内水平上进行比较。该项目将检验一个耐人寻味的生物地球化学假说，并冲击“微生物园艺”这一非常吸引人的概念。

The burrows of macro-infaunal organisms are generally sites of intense microbial activity and often harbor abundant populations of microorganisms. Since the various infaunal species differ greatly in their biology (e.g., feeding guild, motility) and specifically, in aspects of their burrow construction and ventilation, it is reasonable to anticipate that the microbiology of their burrows will also vary. This project will test whether a burrows' increased microbial abundance and activity simply represents enhancement of ambient microorganisms or whether there are specific microbial populations that predictably occur in burrows, independent of the ambient microbial community. A comprehensive assessment of these complex microbial communities will require non-selective methods; the microbes' phospholipid, ester-linked fatty acids (PLFA), the chief constituent of membrane lipids in eubacteria and eukaryotes will be examined. These PLFA, which have already been extracted from field samples of burrows and ambient sediments, are powerful, discriminating tools for determining microbial biomass, composition, and even physiological condition. These biochemical markers will be used to compare the burrow microbes of five infaunal species, representing three phyla, sampled across six sites. Comparisons will be made at interspecific and intraspecific levels using multivariate analysis. This project will test an intriguing biogeochemical hypothesis and impinge on the very attractive concept of "microbial gardening".