Coral reefs of the Wakatobi: Processes of reef growth and loss

Abstract

Coral reef accretion (net reef growth) is the result of complex and dynamic interactions between reef building organisms, bioeroders and the environment. Coral calcification often forms the 'measureable' portion of net reef growth, and is dependent upon the successful symbiotic relationship between cnidaria and photosynthetic dinoflagellate microalgae (Symbiodinium spp.). Light is thus a crucial resource for coral growth. Processes of reef loss include abiotic (storms, disturbance events and climate change) and biotic (bioeroders and corralivores) factors. To assess reef accretion, an understanding of the relationship between coral growth and loss, environmental variables and biotic eroders is vital. Reef systems that have both high biodiversity and varied environmental conditions are prime 'study grounds' to assess these complex interactions. An important example is the Wakatobi National Park (WNP), which is a centre for biodiversity but also has active long-term projects across a range of environments. This chapter examines the underlying physiology of the coral symbiotic relationship, and how this relates to reef growth by using studies from both the WNP and other systems. Understanding these processes remains a critical first step in any reef management strategy plan, but current methods by which reef growth can be assessed often lack the resolution and accuracy needed to relate to changes of environment. Consequently, this chapter discusses benefits and limitations of certain techniques used to assess reef growth. Ultimately, accurate coral growth measurements will improve our ability to model future ecosystem change, and should therefore be a priority research area to support future reef management and conservation strategies. Processes of reef loss are then discussed with regard to the impact of bioeroders, environmental perturbations and anthropogenic stressors upon primary and secondary reef framework. © 2010 by Nova Science Publishers, Inc. All rights reserved