Temporal and Spatial Variability of Epibenthic Megafaunal Communities from the Arctic Deep-Sea LTER Observatory HAUSGARTEN

• Main Author: Taylor, James
• Format: Thesis
• Language: unknown
• Published: 2017
• Subjects: Arctic; Fram Strait
• Online Access: https://epic.awi.de/id/eprint/45271/; https://hdl.handle.net/10013/epic.51770

The Long-Term Ecological Research (LTER) observatory HAUSGARTEN was established in the eastern Fram Strait in 1999 and since then has yielded a large data set on faunal, bacterial, biogeochemical, hydrological and geological properties. Within this thesis I explore spatial and temporal variations of the epibenthic megafaunal communities at three stations (N3, HG-IV and S3), as well as drivers for such variation, using primarily the image analysis of photographic images from 2004 – 2015. Following a brief introduction, Chapter II investigates potential variation within regional- (between different stations 60-110 km apart) and local- (within stations along photographic transects of < 4 km length) scales. Presented is data from N3, HG-IV and S3 from 2011 regarding variations in epibenthic megafaunal densities, community structure, diversity indices and biogenic habitat features. While there were significant regional-scale variations between the stations in these categories, there was only local-scale variability observed at HG-IV, likely corresponding to relevant slope effects. Each station, despite large taxonomic overlap, harboured completely separate communities. In Chapter III I assess temporal variability at stations N3 and S3 between 2004 – 2011. Once again, each station showed significant variations in community structure, megafaunal densities, and diversity over time. The largest increase in density was recorded at N3 from 12.08 (±0.39; 2004) individuals m-2 to 35.21 (±0.97; 2007) ind. m-2. This result coincides with a four-fold increase in sediment bound chloroplastic pigment equivalent (CPE). Three taxa that had a large effect on the temporal variations in the community structure were Kolga hyalina, Mohnia spp. (N3 & S3), and Elpidia heckeri (S3). Chapter IV focuses on temporal population dynamics of these three taxa. Length-weight conversion factors derived from physical specimens were used to convert lengths measured via image analysis to biomass, which were then compared with abundance data. On ...