The ocean's loudest invertebrates may be silenced by acidification

March 16, 2016 by Robyn Mills

Snapping shrimps, the loudest invertebrate in the ocean, may be silenced under increasing ocean acidification, a University of Adelaide study has found.

Published today in the journal Proceedings of the Royal Society B, the researchers report that under forecast levels of CO2 predicted to be found in oceans by the end of the century, thesound of snapping shrimps would be reduced substantially.

This is expected to have profound consequences for many species that rely on sound cues for information about the location and quality of resources (food, shelter, partners and potential predators).

"Coastal reefs are far from being quiet environments ─ they are filled with loud crackling sounds," says Mr Tullio Rossi, PhD candidate in the University's School of Biological Sciences.

"Shrimp "choruses" can be heard kilometres offshore and are important because they can aid the navigation of baby fish to their homes. But ocean acidification is jeopardising this process."

The snapping shrimp is the most common and noisiest of the sound-producing marine animals in coastal ecosystems. They can produce sounds of up to 210dB through the formation of bubbles by the rapid closing action of their snapping claw, used as a warning sign to scare off predators and in their own hunting.

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Oceans Will Not Survive ‘Business as Usual’

BRUSSELS, Mar. 12, 2012 (IPS) - Our oceans face a grim outlook in the coming decades. Ocean acidification, loss of marine biodiversity, climate change, pollution and over-exploitation of resources all point to the urgent need for a new paradigm on caring for the earth’s oceans—"business as usual" is simply not an option anymore, experts say. 

The extreme rate of acidification – the term used to describe the decrease in ocean pH levels caused by man-made CO2 emissions – has happened before, Carol Turley of Plymouth Marine Laboratory said, a claim that might have been comforting if she hadn’t been referring to the time when dinosaurs died out. 

This is a "huge environmental crisis," she told attendees at an information session at European Parliament this month, addressing challenges and solutions for the world’s oceans months ahead of the United Nations Conference on Sustainable Development, Rio+20, slated to be held in Brazil in June. 

Turley joked that she’s often called the "acid queen" because of her bleak message, though the plight of more than 70 percent of the earth’s surface is not in the least bit humorous. 

Each year, the ocean absorbs roughly 26 percent of total CO2 emissions, which have increased by 30 percent since the beginning of the Industrial Revolution in 1750, according to the International Ocean Acidification Reference User Group. 

Ocean acidification affects marine life with calcium carbonate skeletons and shells, making them sensitive to even small changes in acidity. Acidification also reduces the availability of calcium for plankton and shelled species, which constitute the base of the entire marine food chain, creating a disastrous domino affect that could wipe out entire ecosystems. 

"[The] earth system is truly under the influence of man," said Wendy Watson-Wright, assistant director general and executive secretary of the Intergovernmental Oceanographic Commission (IOC) of the United Nations Education, Scientific and Cultural Organisation (UNESCO). 

The oceans could be 150 percent more acidic by 2100, she added. This means drastic decreases in yields from fisheries, and mass extinction of marine life. 

The world is currently losing natural resources at a rate humans haven’t even begun to describe, she said. 


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