Seaweed needs good bacteria too

Coastal urbanisation affects microbial communities on a dominant marine holobiont

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Just as we need ‘good’ bacteria for health and wellbeing, so too do seaweeds, whose microbes are under pressure from urbanisation, placing coastal ecosystems at risk, a study innpj Biofilms and Microbiomes has shown.


Kelps are crucial marine habitat forming seaweeds in temperate rocky shores, and are increasingly threatened worldwide by human activities such as habitat modification and climate change, said the study’s lead author Dr Ezequiel Marzinelli from the University of New South Wales and Singapore Centre for Environmental Life Sciences Engineering.


Bacteria play a fundamental role in the normal development and survival of their hosts, and the effects of urbanisation can impact on ‘healthy’ microbes. This carries potential ecological consequences for key habitat-forming species such as kelp, that support the survival of other plants and animals such as abalone, lobsters and many fish species.


In the ocean, natural habitats are being modified by artificial structures such as marinas and seawalls. The authors found that these structures alter the microbes associated with a crucial marine habitat like kelp forests.


“Kelp on artificial structures have higher amounts of ‘bad’ microbes that can cause diseases and that can make seaweeds more susceptible to being colonised, or fouled, by invaders and/or eaten,” Dr Marzinelli said.


“Given the critical role seaweeds play in coastal ecosystems, this is bad news. However, we may be able to counter this effect by understanding how we can promote ‘good’ or beneficial microbes that provide resilience to hosts in adverse environments,” he said.


“We view this as a potential next step in order to conserve and manage biodiversity.”

Ben Libberton

Science Communicator, Freelance

I'm a freelance science communicator, formerly a Postdoc in the biofilm field. I'm interested in how bacteria cause disease and look to technology to produce novel tools to study and ultimately prevent infection.