Climate change has killed off several coral reefs. Now, scientists are looking into whether artificial coral reefs could function similarly to natural coral reefs lost due to climate change.
The Impact of Climate Change on Coral Reefs
Last September 2023, the Earth's average temperature went 1.75 degrees Celsius over the baseline temperatures of the pre-industrial times. This breached the threshold of 1.5 degrees Celsius, at which global leaders agreed to try to limit global warming in the long run.
At this rate, global warming would make it difficult for coral reefs in the ocean to survive. This is the same for communities that depend on coral reefs for food.
According to assessments made by the Intergovernmental Panel on Climate Change, even if climate change is kept at the most optimistic conditions, as much as two-thirds of the world's coral reefs may deteriorate in the coming decades.
Artificial Coral Reefs
Given this, restoring all the coral reefs lost because of climate change is impossible. However, as some scientists try to study the preservation of these habitats, they are hopeful that artificial coral reefs, consisting of concrete or other hard materials, could replicate some natural reef forms and keep some of their benefits.
Their recent study is the first to examine if artificial reefs could function similarly to real coral reefs. While the results show that this is not yet the case, artificial coral reefs are starting to mirror some of natural coral reefs' key functions, and as time passes, artificial reefs will get better at doing so.
Coral reefs support several species, even as these reefs grow in tropical waters with minimal nutrients. This left naturalist Charles Darwin puzzled, which led to the claim being dubbed Darwin's Paradox.
In a coral reef system that is healthy, dead animal nutrients, as well as feces, rapidly get consumed by the creatures that dwell in the reef. These creatures include invertebrates and small fish. Larger animals typically consume these small animals. This ensures that nutrients do not go up, so they stay at minimal levels that prevent the overgrowth and smothering of algae.
Suppose artificial reefs are capable of similarly functioning as natural reefs. In that case, it may entail expectations that they could quickly process nutrients inside their system and maintain low levels of nutrients. This would show that these ecosystems are highly productive and can support abundant and diverse wildlife even if several natural ones die.
The researchers tried to accurately compare artificial and natural reefs by looking into their nutrient levels and storage.
The deployed structures, amounting to more than 15,000 reefs, cover roughly 2 hectares. However, these reefs are beginning to exhibit signs that they have similar functions as real communities of coral reefs.
High phosphate levels were detected in water samples taken just below the sand near these artificial reefs. This serves as evidence that several fish are excreting. Moreover, nutrient levels were measured similarly or lower in water samples taken above the sediments compared to those found in natural reefs. This shows that the artificial reef was rapidly recycling the nutrients.
However, the sediments surrounding the structures kept lower carbon levels than those that engulf natural reefs. The researchers think these variations could be linked to invertebrate species abundance, which were common in natural reefs but only found in small but growing numbers in artificial structures. The researchers think that as these species grow as time passes, the reefs will functionally become similar to their natural counterparts.
The study serves as a ray of hope regarding how artificial reefs could mirror some natural reef functions. It also suggests that these artificial structures may take five years to start functioning like real ones, stressing the urgency to commence recovery programs.
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