Spatial variation in the morphological traits of Pocillopora verrucosa along a depth gradient in Taiwan

PLoS One. 2018 Aug 17;13(8):e0202586. doi: 10.1371/journal.pone.0202586. eCollection 2018.

Abstract

Pocillopora verrucosa is a widely distributed depth-generalist coral that presents plasticity in its skeletal macro- and microstructure in response to environmental gradients. Light and water movement, which covary with depth, are the main environmental drivers of morphological plasticity in this genus; however, assessing environmentally-induced plasticity may be confounded by the extent of interspecific variation in Pocillopora. We examine the morphology of 8 typed P. verrucosa specimens collected along a depth gradient ranging from 7 to 45 meters and comprising 3 sites throughout Ludao, Taiwan. We measured 36 morphological characters, 14 which are novel, in 3 regions on the corallum-the apex, branch and base-in order to quantify their relationship to site and depth. We found significant correlation between depth and 19 morphological characters, notably branch verruca area, branch verruca height, base verruca spacing, base spinule length, and branch corallite area. 60% of microstructural characters and 25% of macrostructural characters showed a correlative relation to depth, suggesting that depth acclimatization is manifested primarily at the microstructural level. Canonical discriminant analysis of all morphometric characters by depth supports clustering into 3 groups: an overlapping 7m and 15m group, a 23-30m group, and a 38-45m group. Canonical discriminant analysis by site supports clustering into low- and high-current sites, differentiated primarily by branch septa width, base septa width, pre-terminal branch width, terminal branch maximum length, and terminal branch minimum length. We conclude that distinctive patterns of morphological variation in mesophotic specimens of P. verrucosa could reflect the effects of abiotic parameters such as light and water flow. Elucidating the mechanisms behind the morphological changes that occur in response to environmental gradients can help clarify the role that physiological plasticity plays in the acclimatization of corals to the unique environmental settings of mesophotic coral ecosystems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization / genetics
  • Acclimatization / physiology*
  • Animals
  • Anthozoa / genetics
  • Anthozoa / physiology*
  • Coral Reefs*
  • Ecosystem*
  • Phenotype
  • Taiwan
  • Water Movements

Grants and funding

DS and SDP are recipients of the Taiwan International Graduate Program Fellowship. This research was funded by a Taiwan Ministry of Science and Technology Grant number 103-2621-B-001-004-MY3 to CAC (https://www.most.gov.tw/?l=en) and Taiwan Ministry of Science and Technology Grant number 106-2611-M-002-008 to VD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.