Title
Increased Terrestrial Disturbances Modify Skeletal Properties and
Mechanical Strength of Hard Corals
Author(s)
Mwachireya, Shaaban A. ;McClanahan, , Tim R.;;Cote, , Isabelle M. ;Hartwick, Brian E.
Published
2016
Publisher
Environment and Natural Resources Research
Abstract
Skeleton properties determine coral survival by influencing the range of hydraulic conditions colonies can
withstand, selection of suitable habitat, ability to compete for space and light, repair damage and the overall
fitness and ecological success of scleractinian corals. Skeletal properties of 16 coral species comprising 3 growth
forms collected from Kenyan coral reef lagoons were investigated and found to vary considerably not only
between species but between reefs as well, with corals exposed to both sediment and nutrients showing
consistent lower skeleton density and strength but high porosity compared to those from sediment-unaffected
reefs. Further, high skeletal density and strength but low porosity values were measured in branching relative to
other growth forms. The present findings also suggest that the negative effects of nutrients on skeleton properties
may be counteracted by high hydrodynamic energy, resulting in stronger skeletons in high hydrodynamic
energy-nutrient-polluted reef habitats relative to pristine reefs. These findings have important ecological and
management implications with regard to the existence, persistence, productivity and protective value of reefs,
damage risks, maintenance and conservation of biological diversity with respect to future global climate change
events. Consequently, appropriate watershed, reef and fisheries management options that address the impacts of
local anthropogenic stresses (sediments, nutrients, overexploitation) would be expected to alleviate the effects of
these disturbances and have the potential to minimize future large-scale coral reef damage resulting from
increased and frequent global climate change events, such as increased ocean acidification (due to elevated
atmospheric CO2) and sea surface temperature.
Keywords
coral skeleton;density;growth form;porosity;sediment;strength;anthropogenic disturbances
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