1

People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.

2

Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution

3

Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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Scientists have found that high carbon dioxide levels cause squid to bungle attacks on their prey.

PhD candidate Blake Spady from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU) led the investigation. He said that the oceans absorb more than one-quarter of all the excess carbon dioxide (CO2) released into the atmosphere by humans and this uptake of additional CO2 causes seawater to become more acidic.

“Climate models project that unless there is a serious commitment to reducing emissions, CO2 levels will continue increasing this century to reach levels that will have far-reaching effects on sea life,” he said.

Mr Spady said the team chose to study cephalopods (a group that includes squid, cuttlefish and octopuses) because while most previous behavioural studies have focused on fishes, the effects of elevated CO2 on highly active invertebrates is largely unknown.

“Cephalopods also prey on just about anything they can wrap their arms around and are themselves preyed upon by a wide range of predator species, so they occupy an important place within marine food webs.”

The scientists tested the effects of elevated CO2 on the hunting behaviours of pygmy squid and bigfin reef squid.

“For pygmy squid, there was a 20% decrease in the proportion of squid that attacked their prey after exposure to elevated CO2 levels. They were also slower to attack, attacked from further away, and often chose more conspicuous body pattern displays at elevated CO2 conditions.

Bigfin reef squid showed no difference in the proportion of individuals that attacked prey, but, like the pygmy squid, they were slower to attack and used different body patterns more often.”

Mr Spady said both species showed increased activity at elevated CO2 conditions when they weren’t hunting, which suggests that they could also be adversely altering their ‘energy budgets’.

“Overall, we found similar behavioural effects of elevated CO2 on two separate cephalopod orders that occupy largely distinct niches. This means a variety of cephalopods may be adversely affected by rising CO2 in the oceans, and that could have significant consequences in marine ecosystems,” said co-author Dr Sue-Ann Watson.

“However, because squid have short lifespans, large populations, and a high rate of population increase, they may have the potential to adapt to rapid changes in the physical environment,” Mr Spady added.

“The fast lifestyle of squid could mean they are more likely to adapt to future ocean conditions than some other marine species, and this is the next question we intend to investigate.”

Paper: Spady, BL, Munday, PL, Watson, S-A (2018). Predatory strategies and behaviours in cephalopods are altered by elevated CO2 Global Change Biology doi: 10.1111/gcb.14098

Images: for media use can be found here. Please credit as marked.

Contacts:

Blake Spady
PhD candidate at Coral CoE/ JCU
Phone: +61 456 777 883
Email: blake.spady@my.jcu.edu.au

Dr. Sue-Ann Watson
Senior Research Fellow, Coral CoE
Phone: +61 7 4781 5270
Emailsueann.watson@jcu.edu.au

Prof. Philip Munday
Reef Research Leader, Coral CoE
Phone: +61 7 47815341
Emailphilip.munday@jcu.edu.au

Melissa Lyne
Acting Communications Manager, Coral CoE
Phone: +61 415 514 328
Email: melissa.lyne@jcu.edu.au

 

 

New research examining the possible impacts of ocean acidification provides fresh hope for the survival of reef fish.

Just as when a camera lens comes into focus, the latest research published today sharpens understanding of the implications of ocean acidification on reef fish behaviour, yielding promising results for their current and near-future survival.

Chemical changes in the ocean, as a result of climate change, are leading to a more acidic environment, referred to as ‘ocean acidification’ (OA). In a laboratory setting, these changes have been shown to lead to a range of risky behaviours in the affected fish, with some fish unable to flee from their finned foes effectively.

But, when researchers recalibrated experiments to adjust for natural daily changes in concentrations of dissolved carbon dioxide (CO2), the primary chemical driver of OA, they found that the fish were less affected than previously thought.

“Shallow water habitats where reef fish live can experience substantial natural fluctuations in water chemistry throughout the day,” explained senior author Professor Philip Munday, of the ARC Centre of Excellence for Coral Reef Studies (CoralCoE) at James Cook University.

“For example, carbon dioxide levels on coral reefs are often much lower during the day than they are at night.

“Our data suggests that these natural daily changes in water chemistry are enough to provide fish with a recovery period, reducing their sensitivity to higher carbon dioxide levels,” said Michael D. Jarrold, lead author of the study and PhD student at James Cook University.

The study published today in Scientific Reports, utilised state-of-the-art facilities at James Cook University and at the Australian Institute of Marine Science’s National Sea Simulator (SeaSim) to mimic the natural conditions of a coral reef environment.

“It’s the first time these dynamic natural conditions have been reproduced in a laboratory setting to test  their potential influence on the behaviour of coral reef fish,” explained Mr. Jarrold.

“We are thrilled about what we’ve found,” he added. “Our results provide a greater level of optimism for reef fish populations in the future.”

Previous OA research has largely used stable, open ocean conditions to guide the experimental design.

“Broadly speaking, such studies reported reduced anti-predator responses, as compared with the control group,” said Prof Munday.

“Such abnormal behaviours were feared to pose significant ecological consequences for fish populations,” he explained.

The researchers’ ability to precisely control the complex combinations of environmental variables required to accurately simulate both naturally occurring and human-influenced water conditions was crucial to achieving this breakthrough.

“With the world’s most advanced experimental marine technology at our finger tips, and the considerable efforts of our specially skilled team, the SeaSim was able to recreate the natural daily CO2 cycles found on the reef,” said Craig Humphrey, co-author and SeaSim precinct manager at the Australian Institute of Marine Science.

“We’re excited to play a part in such fantastic and novel research.”

The paper titled: “Diel CO2 cycles reduce severity of behavioural abnormalities in coral reef fish under ocean acidification” is available online at:

http://www.nature.com/articles/s41598-017-10378-y

 

IMAGES

Images must carry credits as listed in Dropbox folder

https://www.dropbox.com/sh/ksut22cjn88d1zj/AACX8BUsDQnjpx8s441wU1xsa?dl=0

 

CONTACTS

Prof Philip Munday
ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 0408 714 794, +61 (0)7 4781 5341 (AEST)
Email: philip.munday@jcu.edu.au

Mr Michael D. Jarrold
James Cook University
Email: michael.jarrold@my.jcu.edu.au

 

FOR MORE INFORMATION

Ms Catherine Naum
Communications Manager
ARC Centre of Excellence for Coral Reef Studies
Phone: +61 (0) 0428 785 895, +61 (0)7 4781 6067 (AEST)
Email: Catherine.Naum1@jcu.edu.au

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Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au