Influence of bathymetry on macroepibenthic communities

• Main Authors: Winkler, Malte, Laudien, Jürgen, Fillinger, Laura, Häussermann, Verena
• Format: Conference Object
• Language: unknown
• Published: International conference of young marine researchers and engineers 2013
• Subjects: Antarc*; Antarctica; E. Antarctica
• Online Access: https://epic.awi.de/id/eprint/33526/; https://hdl.handle.net/10013/epic.41978

The cold-water hydrocoral Errina antarctica provides habitat for numerous macroepibenthic species. Gaining knowledge about the highly diverse communities associated with E. antarctica is crucial for efficient protection of the ecosystems, which are strongly threatened by aquaculture and other human activities. This investigation for the first time provides information on quantitative composition of benthic communities associated with E. antarctica. Structure of macroepibenthic community associated with E. antarctica in three bathymetric zones (Zone 1: 10-20 m; Zone 2: 20-30 m; Zone 3: 30-40 m) from four diving sites in the Chilean fjord region is described by analyzing 260 images extracted from videos recorded via ROV. Community compositions were investigated based on abundances using multivariate statistical methods (SIMPER, ANOSIM, MDS). Ecological indices (S, H´, d, J´) were calculated. Distribution of differently sized E. antarctica-colonies (small [diameter < 10 cm], medium [10 cm < diameter < 20 cm], large [20 cm < diameter]) was investigated and set into context with analysis of community structure. No significant influence of depth on the investigated community was detected. Differences between the four diving sites seem to overlay bathymetric effects. Annelids (mainly genus spirorbis) dominate all bathymetric zones, in line with former investigations. ANOSIM indicated poor distinctness between bathymetric zones (GR=0.062). The MDS-plot showed no grouping of bathymetric zones. Low values of ecological indices in Zone 1 are explained by distribution of E. antarctica-colonies. Abundances of colonies of all sizes decreases with depth, portion of small colonies is highest in Zone 1.