Grounding icebergs enhance regional benthic diversity in Antarctica

• Main Authors: Gutt, Julian, Piepenburg, D.
• Format: Conference Object
• Language: unknown
• Published: 2003
• Subjects: Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica; Iceberg*
• Online Access: https://epic.awi.de/id/eprint/8491/; https://hdl.handle.net/10013/epic.19019

Disturbances like forest fires, tree falls or hurricanes are natural and essential processes in ecosystems [1,2]. Their initially catastrophic impacts are followed by beneficial effects on biodiversity [3,4] which is increasingly recognized to be fundamental in ecosystem functioning [5]. Recently, iceberg scouring of the Antarctica seabed has been identified as another important disturbance agent [6]. This finding is inconsistent with the paradigm that high benthic diversity on the deep Antarctic shelf [7] is primarily caused by long-lasting environmental stability.Here we show how iceberg scouring significantly shapes megabenthic structures. Sea-bed video-strips from the Weddell Sea provide evidence that at a local scale between 1 and 100 m, undisturbed glass sponge habitats were more diverse than disturbed ones. However, the increase in habitat heterogeneity caused by iceberg scouring enhanced species diversity at a regional scale (1-100 km). The recolonization seems to be highly variability and barely predictable in terms of time and species composition. Consequently, the Intermediate-Disturbance Hypothesis assuming the existence of competitive displacement at small spatial scales [4] can not be confirmed. Instead the coexistence of different successional stages generally described by the Patch-Dynamics Concept [2] leads to high benthic diversity in Antarctica.