{"id":11351,"date":"2024-03-06T10:00:00","date_gmt":"2024-03-06T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=11351"},"modified":"2024-02-22T10:36:14","modified_gmt":"2024-02-22T10:36:14","slug":"sentinels-of-the-sea-ancient-boulder-corals-are-key-to-reef-survival-in-a-warmer-world","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/sentinels-of-the-sea-ancient-boulder-corals-are-key-to-reef-survival-in-a-warmer-world\/","title":{"rendered":"Sentinels of the sea: ancient boulder corals are key to reef survival in a warmer\u00a0world"},"content":{"rendered":"\n
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\n \n Giacomo d Orlando <\/span><\/span>\n <\/figcaption>\n <\/figure>\n\nKate Marie Quigley<\/a>, James Cook University<\/a><\/em><\/span>\n\n

Seas surrounding Australia this month hit an alarming level<\/a> of warming. It comes on the back of serious marine heatwaves<\/a> in the Northern Hemisphere summer.<\/p>\n\n

Such warming is highly dangerous<\/a> for corals. Every half a degree<\/a> of ocean warming increases their risk of bleaching and potential death.<\/p>\n\n

The best long-term strategy to protecting Earth\u2019s coral reefs is to dramatically cut greenhouse gas emissions and so limit global warming. But in the meantime, we must urgently make corals more resilient and protect those that are vulnerable.<\/p>\n\n

That is particularly true for the huge, ancient features of reefs known as boulder corals. Research suggests they will be a vital part of reef survival in a warmer world.<\/p>\n\n

\n \"A\n
\n An image showing various levels of bleaching alert around Australia as of February 19, 2024.<\/span>\n NOAA Coral Reef Watch<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n

The old-growth trees of the sea<\/h2>\n\n

Boulder corals (Porites<\/em>) can grow to more than 10m high<\/a> and live for more than 600 years<\/a>. In Australia they are often referred to as \u201cbommies\u201d. Each bommie can comprise multiple species, but they\u2019re often a single massive individual.<\/p>\n\n

The corals play a crucial role<\/a> in reefs, including providing habitat for marine life. Importantly, they can maintain these functions<\/a> even when other coral species are absent.<\/p>\n\n

Some species<\/a> are thought to be resistant to stress<\/a>. Old corals have likely experienced<\/a>\n\u2013 and survived \u2013 past warming episodes, proving their resilience<\/a>.<\/p>\n\n

For example, a paper in 2021 described a giant boulder coral discovered on the Great Barrier Reef which was thought to be<\/a> more than 400 years old. It has survived 80 major cyclones, numerous coral bleaching events and centuries of exposure to other threats.<\/p>\n\n

This resilience can benefit the whole reef ecosystem. We can think of boulder corals as akin to old-growth trees in a forest. Just like forests containing big, old trees are more resistent<\/a> to fire<\/a>, studies show a mix of different growth forms, including old and large boulder corals, fare better<\/a> in the long-term under marine warming. <\/p>\n\n

Older and bigger corals may also produce more offspring<\/a>, so can more rapidly replenish the reef after disturbances.<\/p>\n\n

Clearly, as our oceans face unprecedented pressures under climate change, we must protect \u2013 and learn from \u2013 these sentinels of the sea.<\/p>\n\n\n\n\n\n

Preparing for the challenges ahead<\/h2>\n\n

Understanding boulder corals is crucial to predicting how they might cope under climate change, and planning for their protection.<\/p>\n\n

But scientists still have much to learn about boulder corals. In particular, we don\u2019t know<\/a> exactly how many species exist, their life histories and how they evolved. <\/p>\n\n

My colleagues and I are aiming to overcome this knowledge gap. We are studying reefs across Australia, with a particular focus on boulder corals at Ningaloo Reef off Western Australia.<\/p>\n\n

We are creating maps of what species of boulder corals exist and where they are located. And using cutting-edge genomics technology<\/a>, such as DNA sequencing, we are measuring the tolerance of each species to warming and trying to predict when they will reproduce. <\/p>\n\n

Importantly, we are also examining the mutually beneficial relationship between the corals and algae. This relationship provides algae with shelter, gives corals their colour and provides nutrients to both partners. It may also be a main factor<\/a> in coral resistance to warmer temperatures.<\/p>\n\n

So far, we have found more diversity than initially expected. This is exciting because it may signal an increased capacity to resist different types of stress. But the work to fully map Ningaloo\u2019s coral diversity has only just begun.<\/p>\n\n

We hope our findings, once finalised, can inform local community management actions such as:<\/p>\n\n