Exeter Marine Podcast: Becoming Marine Biologists – with Lauren Henly, Emma Weschke and Tim Gordon

This episode was recorded back in early 2019. Ben talks to Lauren Henly, Emma Weschke and Tim Gordon, who are all masters by research or PhD students in Prof. Steve Simpson’s research group (you might remember Steve from an earlier episode, Coral Reef Bioacoustics Part I). The discussion focuses around the research they’re all undertaking, what got them interested in marine biology, and what they have done so far.

 


 

About our guests:

Emma Weschke

At the time of recording Emma was a masters by research student and is now undertaking a PhD with the University of Bristol focusing on coral reef fish ecology and bioacoustics.

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Lauren Henly 

Lauren is a PhD student with the University of Exeter and Natural England studying functional ecology and behaviour of wrasse to inform management of wrasse fisheries. She provided us with the update below:

 “I’m now in the 3rd year of my PhD. I’ve been developing lots of different methods to assess the sustainability and potential impacts of the Live Wrasse Fishery on the south coast. I’m using genetics to look at the population structure of wrasse along the south coast so we can identify the most effective management unit size, using stable isotopes to predict the ecological impacts of the fishery, and working to ensure the views of other stakeholders (including recreational anglers) are considered when developing management measures for the fishery. It’s great being able to use such a broad range of techniques to address a key issue.”

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Tim Gordon

Tim is completing a PhD with the University of Exeter and the Australian Institute for Marine Science focusing on coral reef bioacoustcs, what can you learn from coral reefs by listening to them. You can find out more about Tim’s work in a previous episode – Coral Reef Bioacoustics Part II.

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Topics discussed:

  • Sustainability of wrasse fisheries around the UK.
  • Ecological consequences of marine anthropogenic noise on coral reefs, both during the day and at night.
  • How fish use underwater soundscapes.
  • Using underwater sound to aid marine conservation efforts.
  • The impacts of the degredation of coral reef marine noise
  • Using underwater speakers to make reefs louder.
  • The bigger picture aspects of working in a research group.
  • What got you into marine biology?

 


 

Resources:

 


 

Episode and show notes produced by Ben Toulson and Katie Finnimore.

Check out other episodes of the podcast here.

You can subscribe on most podcast apps, if you’re feeling kind please leave us a review!

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Emily Easman or visit our website!

 

 

Exeter Marine Podcast – Coral Reef Bioacoustics Part II, with Tim Gordon

Show notes

In this episode we talk to Tim Gordon about his work studying coral reef bioacoustics, this is a follow-up from the interview we did with Steve Simpson, which you can find here.


About our guest: Tim Gordon

Tim Gordon is currently undertaking a PhD focussing on how human activities impact underwater bioacoustics. Tim’s area of study uses fieldwork as well as laboratory work and computational analysis, to assess the likely effect of noise pollution on marine life, with the aim of determining how they can best be managed.

Tim was recently rewarded for his science communication efforts, by winning the FameLab International prize for 2019, becoming the first UK national champion of the competition since going global.

 


 

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Topics discussed:

  • Importance of soundscapes for marine animals
  • Changes in underwater biological and human sounds
  • Uses and types of sound underwater
  • Process of reef fish using sound to settle in coral reef habitats
  • Effect of noise pollution on fish orientation

 


 

Resources:

Online Talk: Scientists and Explorers Live – “Songs of the Sea” with Encounter Edu

British Council’s page for Tim’s FameLab competition talk

Talk: “Climate Change: Tales from the front line”

Talk: “Helping Nemo find home”

ResearchGate

Google Scholar

Twitter

 


 

Episode and show notes produced by Ben Toulson and Katie Finnimore.

Check out other episodes of the podcast here.

You can subscribe on most podcast apps, if you’re feeling kind please leave us a review!

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Emily Easman or visit our website!

 

 

Investigating Coral Reef Acoustics to Aid Reef Restoration

Words by Ben Williams, 2019 BioScience Graduate

Most people are aware coral reefs throughout the world are struggling one way or another. A range
of issues are responsible including overfishing, pollution and climate change induced bleaching to
name a few. However, coral reef communities provide valuable ecosystem services to a vast number
of individuals, it’s estimated One Billion people have some degree of dependence on these
ecosystems. With much of the world’s reefs degraded or lost it makes conserving those that remain
vital, and restoration of former reefs an important endeavour to many individuals.

The Marine Bioacoustics group in Exeter focuses much of their efforts on understanding the
soundscapes of coral reefs. These soundscapes encompass the entirety of the sound that can be
heard on particular spots of the reef and can be collected using underwater microphones we call
hydrophones. Emerging research suggests a lot can be determined about a reef from a few key
parameters within its soundscape which could be used to indicate the health of the surrounding
reef. A great example is shown in the spectrograms below, where you can hear an audible difference
between the soundscape of a healthy reef and that of a degraded reef:

This short acoustic clip first plays us the buzz of a healthy reef, followed by the quieter setting heard on a degraded reef

A group of us from Exeter’s Marine Bioacoustics group are currently out in Indonesia exploring reef
acoustics further. We’re collaborating with a project set up by Mars™, who have been working on an
intuitive way to restore the reefs in South Sulawesi. They use two key methods in doing so, the first
is coral propagation, where small samples of coral are clipped off live colonies and transported
somewhere new where they grow back at a faster rate than if left on their original colony. The next
step is to attach these to a skeleton system they call ‘Spiders’, which provide a substrate for new
corals to colonise and elevate them slightly above the reef bottom to provide the water flow needed
to bring nutrients to the growing coral. The Mars™ project has implemented large areas of these
spiders around two islands off Makassar with an impressive degree of success in their ability to
restore the reef.

This photo shows some of the several month old spiders placed by the Mars™  team which are showing an impressive rate of growth.

Our team from Exeter is particularly interested in the difference between the soundscapes of healthy and degraded reefs. We’re visiting the Mars™ restoration efforts to help explore the differences in soundscapes between their restored sites, degraded sites and baseline healthy sites. The hope is that in the future we will be able to show restored sites match the soundscape of healthy sites, and a quantifiable difference between the restored sites and degraded sites will be observable. We’re trialing this out using hydrophones which we’ve been placing daily on different sites within the reefs to determine whether this is a feasible methodology in comparing the reef soundscape.

Ellie May deploying a GoPro to film our quadrat used for the underwater playback test.

We’re also exploring the possibility of using ‘soundscape enhancement’ to help fine tune the ecology of the reef at a local scale to bring about restorative impacts. This is a highly innovative approach in which submersible loudspeakers are placed on patches of degraded reefs where they play recordings that may help recovery of the reef. A proof of concept of this was only recently provided in a 2018 study authored by Tim Gordon, who is now leading the expedition out here in Indonesia, and other members of the
Marine Bioacoustics group. The study found that larval and juvenile recruitment was greater at sites where healthy reef noise was played compared to sites where degraded reef noise was played. The use of soundscape enhancement is therefore of a great interest to restoration programmes like Mars™ in Indonesia, and we’re also out here to help them investigate whether this could be a potentially useful tool for their restoration. This time we’re trialing playback methods that could be used to affect the ecology of adult fish within the reef, primarily regarding their grazing behaviour which is a key process in controlling algae overgrowth at degraded sites.

 

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, biological,  medical, engineering, humanities and social science fields.

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If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

It’s Stressful Being a Coral! Declining Coral Cover on the Great Barrier Reef

Author: Jennifer McWhorter

Jennifer McWhorter is pursuing her PhD in a joint program between the Universities of Exeter and Queensland. Using various climate and ecological modelling techniques, Jen hopes to improve our spatial knowledge of coral reef stressors.

 

The above diagram describes the process of coral bleaching followed by mortality. Source: Great Barrier Reef Marine Park Authority (GBRMPA)

 

Similar to humans experiencing a fever, coral reefs undergo similar stress. The more frequent the fever and the longer the fever lasts, the more life threatening it becomes. Sea surface temperatures in the ocean are increasing at an alarming rate due to human inputs of carbon dioxide into the atmosphere (Ekwurzel et al., 2017). In 2016/2017, the Great Barrier Reef (GBR) experienced two back-to-back severe warming events that caused widespread coral bleaching[1]. According to the Australia Institute of Marine Science, hard coral cover on the GBR has declined at a rate that has never been recorded.

 

Figure 2. “Large-scale spatial patterns in change in coral cover and in heat exposure on the Great Barrier Reef, Australia. A, Change in coral cover between March and November 2016. b, Heat exposure, measured in DHW (in degree C-weeks) in the summer of 2016. Map template is provided by Geoscience Australia (Commonwealth of Australia (Geoscience Australia) 2018).” Source: Hughes, T. P., et al., 2018

 

In addition to coral bleaching, cyclones and crown-of-thorns sea star outbreaks have been the main cause of decline in coral cover on the GBR within the past four years. The northern area of the GBR is expected to have lost about half of its’ coral cover. This estimate reflects the impacts of two episodes of severe coral bleaching from 2014-2017 and two cyclones.  The central reef has experienced a decline in coral cover from 22% in 2016 to 14% in 2018 due to coral bleaching and the ongoing southward spread of the crown-of-thorns sea star. Even though the southern portion of the GBR was not exposed to the 2016/2017 warming events, coral cover has dropped from 33% in 2017 to 25% in 2018. On the southern reefs, the crown-of-thorns sea star outbreaks appear to be the main cause for the most recent decline.

 

During my last trip to Australia, I assisted in injecting vinegar into the crown-of-thorns sea stars at Lodestone Reef on the GBR. The vinegar kills the sea star within 24 hours potentially reducing their threat to hard, or stony corals. Photo Credit: Chris Jones

 

“Clearly the reef is struggling with multiple impacts,” says Prof. Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies. “Without a doubt the most pressing of these is global warming. As temperatures continue to rise the corals will experience more and more of these events: 1°C of warming so far has already caused four events in the past 19 years.”

“Ultimately, we need to cut carbon emissions, and the window to do so is rapidly closing.”

 

 

[1] Coral bleaching – Coral bleaching occurs when the relationship between the coral host and zooxanthellae (photosynthetic algae, NOAA), which give coral much of their colour, breaks down. Without the zooxanthellae, the tissue of the coral animal appears transparent and the coral’s bright white skeleton is revealed. Corals begin to starve once they bleach. (GBRMPA)

 

Additional Resources:

Ekwurzel, B., Boneham, J., Dalton, M. W., Heede, R., Mera, R. J., Allen, M. R., & Frumhoff, P. C. (2017). The rise in global atmospheric CO2, surface temperature, and sea level from emissions traced to major carbon producers. Climatic Change144(4), 579-590.

Hughes, T.P. & Kerry, J.T. Back-to-back bleaching has now hit two-thirds of the Great Barrier Reef. The Conversation https://theconversation.com/back-to-back-bleaching-has-now-hit-two-thirds-of-the-great-barrier-reef-76092 (2017)

Hughes, T. P., Kerry, J. T., Baird, A. H., Connolly, S. R., Dietzel, A., Eakin, C. M., … & McWilliam, M. J. (2018). Global warming transforms coral reef assemblages. Nature556(7702), 492.

Media Release: Two Thirds of the Great Barrier Reef hit by back-to-back mass coral bleaching

Long-term Reef Monitoring Program – Annual Summary Report on coral reef condition for 2017/2018

 

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!