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


Contact
James.Taylor [ at ] awi.de

Abstract

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 the whole the trend of increased mean mass per individual resulting in lower abundances was observed and vice versa. There were three exceptions to this trend including the first recorded mass migration for K. hyalina, perhaps deep-sea epibenthic holothurians in general, potentially in response to the CPE increase first mentioned in Chapter III. Finally to complete the thesis, Chapter V presents the general conclusions for the research presented in the previous chapters.



Item Type
Thesis (PhD)
Authors
Divisions
Primary Division
Programs
Primary Topic
Research Networks
Peer revision
Not peer-reviewed
Publication Status
Published
Eprint ID
45271
Cite as
Taylor, J. (2017): Temporal and Spatial Variability of Epibenthic Megafaunal Communities from the Arctic Deep-Sea LTER Observatory HAUSGARTEN PhD thesis, University Oldenburg.


Share

Research Platforms

Campaigns


Actions
Edit Item Edit Item