Clonal Growth Patterns in Colonial Anthozoan Corals
byEleonora Re, Sebastian Schmidt-Roach, Eva Llabres, Tomas Sintes, Carlos M.Duarte
Book chapterYear:2024DOI:10.1201/9781003477518‑6
Abstract
Corals are modular organisms that use asexual reproduction (i.e., budding) to increase
the size of the colony by adding new polyps. Clonal modularity offers several advantages, such as
the ability to sustain partial mortality, redistribute resources internally, replace or repair single mod‑
ules, and delay senescence, potentially supporting millenary growth. Despite the global importance
of coral reefs, little is known about clonal growth rules in anthozoan corals. Coral clonal growth
was reviewed to synthetise current understandings and identify gaps driving future research efforts.
Despite corals present high plasticity, their growth is dictated by strong intrinsic regularities at dif‑
ferent life stages and modularity levels. For example, a six‑polyps crown with fixed distances among
polyps is typically formed in the early development stages of Stylophora pistillata larvae. Similarly,
specific developmental regularities are observed in the budding of azooxanthellate Dendrophylliidae
polyps, which are consistently maintained across generations and species. In Octocorallia, colony
shape is preserved by maintaining a constant ratio between the total number of branches and mother
branches. Concurrently, environmental factors (i.e., light and hydrodynamics) play a fundamental
role in shaping the final morphology of the colony, driving the architectural design at different levels
of modularity. Some species revealed higher plasticity at the branching level in contrast with the
predetermined shape assumed by the colony. Several models have been proposed to describe the
environmental modulation of coral growth, mostly in branching forms. However, a holistic, universal
model applicable to a broader range of coral taxa is still lacking. Understanding the fundamental
rules underpinning coral clonal growth is essential to improving predictions of coral reef recovery,
inferring stress on coral colonies and guiding restoration efforts.