The abundance of coral species at different depths is unrelated to energy availability, according to a new study analyzing diversity in Australian reef.
Studies from James Cook University, Lancaster University, Copenhagen and Technical University of Queensland, published in Biological Letters reveal neither energy availability nor, in combination with other local factors, causes differences. in the diversity of coral species in depth.
The study, funded by the Australian Research Council Center of Excellence, generated an unprecedented data set of 8,446 colonial colonies in six reefs in Kimbe Bay, Papua New Guinea.
This allowed the team to conduct a robust test of the drivers that underlie how the corals are distributed for depth for the first time, allowing them to test the theory that there will be more species diversity when there is more high energy available.
For corals, the greatest diversity was expected in the shallows because they depend on the energy of the sunlight. To test this idea, the researchers examined the depth range between 0 and 45 meters, reaching much deeper than most previous studies and covering 98 percent of the gradient of light.
Contrary to theory-based expectations, research has revealed that the diversity of corals among team samples is greatest at a depth of between 15 and 20 meters.
Lead author Dr. Edward Roberts of James Cook University says: "Our understanding of how the diversity of corals varies in depth is limited by the lack of high quality data due to the difficulty of in-depth studies.
" to overcome this in our study at Kimbe Bay. This allowed us to test the classical hypothesis for the types of energy that offers the greater the available energy, the greater the diversity, since theoretically more energy allows more individuals to exist. This in turn allows more species to maintain large enough populations to avoid local extinction.
"Our results do not agree with this classic explanation of how diversity changes with energy. Instead, the shallowest depths were of fewer species, the model also poorly explained by alternative explanations such as coral competition or environmental distortion. "
The results of the study give rise to new theories on the distribution of diversity .
Co-author Dr. Sally Keith of the Lancaster Center for the Environment says, "Hyper diverse coral reefs are ideal ecosystems for testing theories about how diversity is distributed in nature, so it's really interesting that our results do not support classical hypotheses. "
" More broadly, our analyzes call into question the appropriateness of these hypotheses more generally in terrestrial, marine, and freshwater systems, suggesting that ecologists may need to rethink the underlying causes of these underlying models. of diversity. "
Fluffy fish can have their coral and eat it too
Testing biodiversity theory using the richness of coral species to build reefs through a depth gradient, Biological Letters (2019). royalsocietypublishing.org/doi… .1098 / rsbl.2019.0493
Classical energy theory fails to explain the distribution of corals by depth (2019, October 29)
retrieved October 30, 2019
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