London, UK – August 18, 2025
A new and alarming study is shining a harsh light on climate change’s impact on marine life, revealing that two of its most insidious effects—ocean acidification and warming—are causing the skeletal foundations of the Mediterranean Sea to weaken and dissolve. The research, published by the Institute of Marine Sciences, shows that Mediterranean bryozoans are crumbling under this dual pressure, a silent process that threatens to dismantle the intricate habitats that underpin the region’s rich marine biodiversity.
Bryozoans, often overlooked by the public, are essential to the health of the marine ecosystem. These microscopic animals form vast, delicate colonies that build hard, calcium carbonate structures, creating complex reefs and underwater forests. These structures serve a vital role as “ecosystem engineers,” providing shelter and nurseries for countless other species, including juvenile fish, octopuses, small crabs, and seahorses. Without these living foundations, the entire ecosystem is at risk of collapse.
The new study, a three-year observation and lab-based analysis, found that the bryozoans’ ability to build and maintain their calcium carbonate skeletons is being critically compromised. The primary culprit is the rising absorption of atmospheric carbon dioxide by the world’s oceans. This process, known as ocean acidification, leads to a drop in the water’s pH, making it more corrosive to calcium carbonate. The research team’s lead scientist, Dr. Elena Rossi, explained, “It’s a chemical assault on a massive scale. For these bryozoans, it’s like their very homes are being slowly dissolved by a weak acid.”
The problem is compounded by the unprecedented rate of ocean warming. The Mediterranean Sea, a semi-enclosed basin, is warming faster than the global average, with surface temperatures hitting record highs this summer. This increased thermal stress forces the bryozoans to expend more energy on survival, leaving less available for skeletal formation and reproduction. The study found a direct correlation between warmer temperatures and a higher prevalence of weak, malformed bryozoan colonies.
The implications of the bryozoans’ decline are far-reaching. The loss of their structural habitats could trigger a domino effect, leading to a collapse of entire food webs. Species that depend on these habitats for protection from predators would be left vulnerable, causing their populations to plummet. This, in turn, would affect larger marine predators and ultimately impact the local fishing industries that are a cornerstone of many coastal economies around the Mediterranean.
The findings serve as a powerful and urgent warning. While much of the public’s focus has been on the threats to coral reefs, this study underscores that the problem of ocean acidification and warming is a systemic one, affecting a wide range of marine organisms that are fundamental to the health of the ocean. The hope, according to scientists, lies in aggressive global action to reduce carbon emissions and in the implementation of local conservation efforts to protect existing habitats. Without a coordinated effort, the vibrant, living foundation of the Mediterranean could continue to silently crumble away.
Headline Points
* A Foundation Crumbles: A new study reveals that climate change is causing Mediterranean bryozoans—crucial “ecosystem engineers”—to weaken and dissolve.
* Dual Threat: The organisms are being affected by the dual pressures of ocean acidification and warming, which disrupt their ability to build and maintain their calcium carbonate skeletons.
* Food Web At Risk: The loss of bryozoans’ intricate habitats could trigger a domino effect, threatening to destabilize the entire Mediterranean marine food web and impacting local fisheries.
* Systemic Problem: The report highlights that ocean acidification is a systemic threat to a wide range of marine life, not just iconic species like coral.
* Call for Action: Scientists are urging for a global reduction in carbon emissions to address the root cause of the problem.
