30 May 2023
 | 30 May 2023

Building your own mountain: The effects, limits, and drawbacks of cold-water coral ecosystem engineering

Anna-Selma van der Kaaden, Sandra R. Maier, Siluo Chen, Laurence H. De Clippele, Evert de Froe, Theo Gerkema, Johan van de Koppel, Christian Mohn, Max Rietkerk, Karline Soetaert, and Dick van Oevelen

Abstract. Framework-forming cold-water corals are ecosystem engineers that build mounds in the deep-sea that can be several hundred meters high. The effect of the presence of cold-water coral mounds on their surrounding is typically difficult to separate from environmental factors that are not affected by the mounds. We investigated the environmental control on cold-water coral reefs at multiple spatial scales, using annotated video transects data, spatial variables (MEMs) and hydrodynamic model output in a redundancy analysis and with variance partitioning. Using available hydrodynamic simulations with cold-water coral mounds and simulations where the mounds were artificially removed, we investigated the effect of coral mound ecosystem engineering on the spatial configuration of reef habitat and discriminated which environmental factors are and which are not affected by the mounds.

We find that, due to the interaction between the coral mound and the water flow, different hydrodynamic zones are created on a coral mound that likely determine the typical benthic zonation of coral rubble at the mound foot, dead coral framework on the mound flank, and living corals near the summit. Moreover, we observed a so-called massenerhebung effect (well-known for terrestrial mountains) meaning that benthic zonation depends on the location on the mound rather than on the height above the seafloor or water depth. Our finding that ecosystem engineering determines the configuration of benthic habitats on cold-water coral mounds has many implications, such as that cold-water corals cannot simply move towards deeper water depths to avoid the adverse effects of climate change.

We further find that downward velocities in winter, related to non-engineered environmental factors, e.g., deep winter mixing and dense water cascading, correlated to substantial differences in reef cover at the broadest spatial scale (20–30 km). Such hydrodynamic processes that stimulate the food supply towards the corals in winter are more important for the reefs than similar hydrodynamic processes in summer. There is much research on the ecosystem engineering effects of cold-water corals, but our results highlight that the influence of non-engineered environmental processes that accelerate the food supply towards the cold-water corals should not be underestimated.

Anna-Selma van der Kaaden et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-949', Anonymous Referee #1, 21 Jun 2023
    • AC2: 'Reply on RC1', Anna van der Kaaden, 16 Aug 2023
  • RC2: 'Comment on egusphere-2023-949', Anonymous Referee #2, 17 Jul 2023
    • AC1: 'Reply on RC2', Anna van der Kaaden, 16 Aug 2023

Anna-Selma van der Kaaden et al.

Data sets

Raw data for "Reef communities associated with 'dead' cold-water coral framework drive high resource retention and fast recycling in the deep sea" Sandra R. Maier

Anna-Selma van der Kaaden et al.


Total article views: 347 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
244 83 20 347 7 8
  • HTML: 244
  • PDF: 83
  • XML: 20
  • Total: 347
  • BibTeX: 7
  • EndNote: 8
Views and downloads (calculated since 30 May 2023)
Cumulative views and downloads (calculated since 30 May 2023)

Viewed (geographical distribution)

Total article views: 335 (including HTML, PDF, and XML) Thereof 335 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 22 Sep 2023
Short summary
Combining hydrodynamic simulations and annotated videos, we separated which hydrodynamic variables that determine reef cover are engineered by cold-water corals and which not, which is typically difficult. Around coral mounds hydrodynamic zones create a typical reef zonation, restricting corals from moving deeper (the expected response to climate warming). But non-engineered downward velocities in winter (e.g., deep winter mixing) seem more important for coral reef growth than coral engineering.