Scientists at Sea Podcast – The Stingray Episode: with Ethan Wrigglesworth and Molly Meadows

In this episode, we get to know our regular presenters a little better. Ethan and Molly talk to Ben, the producer, about the work they have been doing as Masters by Research students for the past two years. Under the supervision of Dr. Lucy Hawkes, Molly and Ethan have been working closely with Dr. Owen O’Shea at the Cape Eleuthera Insitute (CEI) in the Bahamas, to study the stingrays in the local waters.

 

 

Molly and Ethan worked with two data deficient species of stingray; the Southern Stingray, and the Caribbean Whiptail Ray  The main focus of the research was to investigate the rays’ diets. This involved two methods; stable isotopes analysis and stomach content analysis (you can learn more about them in the podcast).

 

Ray team just after having caught a southern stingray along a sandbar. (Ethan first on left, Molly, second from right).

 

Why does this matter?

Well, as Molly and Ethan put it:

Molly holding the tail of a Caribbean whiptail ray presenting the large venomous barb.

 

 

 

“To understand about the diet is actually to understand general ecology… within an ecosystem, what a predator feeds upon… has a great impact on the population sizes of the prey, and there’s a huge amount of energy moving up in that food chain”

 

 

 

 

 

 

How might such research be applied? Well, in the Bahamas there is no legislation for the protection of mangroves.

 

“In the Bahamas, there’s lots of these mangrove creeks, and plenty of fish use them as nursery habitats because they offer a lot of shelter within the roots… stingrays occupy these systems as well… they feed on worms, crabs and things within the sea floor, so they use the mangroves a lot to find (their) food.”

 

You can find out more about why mangroves are so important here.

 

“Beaches are very popular in terms of tourist economy, so (mangroves) get destroyed quite a lot”

 

While the stingrays rely on the mangroves for food, it seems they also offer plenty to the mangroves themselves. To find out exactly what they offer, take a listen to the episode.

 

A free diver going face to face with a large Caribbean Whiptail Ray

 

 

 

You can also find out about some skills you might not know existed, like stingray herding!

 

 

 

 

 

 

 

 

Highschool/Island school student Jake holding a southern stingray during sampling procedures

 

Getting Started with Marine Science

Molly and Ethan initially honed their marine biology skills and interests as undergraduates here at the University of Exeter’s Penryn Campus, studying Zoology and Conservation Biology and Ecology respectively. In their final year they undertook a field course to Eleuthera Island in the Bahamas, this sewed the seeds of their Masters by Research. Click the links to find out more.

 

 

Here is a bonus link mentioned during the episode, enjoy! Household items reviewed for science

 

Videos courtesy of CEIBahamas

Hosted by Ethan Wrigglesworth and Molly Meadows

Episode and show notes produced by Ben Toulson

#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!

 

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!

Scientists at Sea Podcast: Sail Against Plastic

Show Notes

 

 

 

Guests – Flora Rendell and Lowenna Jones

 

 

 

Sail Against Plastic started as an idea to simply undertake a sailing expedition, over just a few months it developed into an Arctic mission to investigate unseen pollutants, namely microplastics and noise pollution.

 

“We are a collaborative expedition hoping to unveil and reveal the invisible pollutants of the arctic”

 

The Sail Against Plastic team. Photo credit – Ben Porter

 

Why the Arctic?

It is well documented that plastic debris has been circulating around our oceans via 5 ocean gyres. It is now thought there maybe a sixth gyre that carries plastic up into the Arctic circle. Recent discoveries supporting this theory have shown that plastic has been found in sea ice.

 

“As sea ice melts that could be opening up more microplastics that have been trapped in that sea ice… it shows that we’ve been influencing the world for a long time”

 

A selection of plastics found on mainland Svalbard. Photo credit – Ben Porter

 

A view from the Blue Clipper: Photo credit – Ben Porter

These pieces of plastic aren’t necessarily what you would expect, while there plastic bottles and bags found in these areas, there may be an even greater prevalence of microplastics, tiny pieces of plastic debris resulting from the breakdown of consumer products and industrial waste.

 

“It’s not these big large pieces of plastic, it’s not a floating island that we’re going to find’

 

At the time of recording, the team, a diverse group of scientists, artists, environmentalists, photographers and videographers, were just a few days away from setting sail on the Barents Sea from Svalbard aboard the Blue Clipper.

 

 

The team’s manta trawl, used to collect microplastics. Photo credit – Ben Porter

 

 

“I think the main thing is making issues that are so strongly linked to humans… making you feel emotive about them… through art and through film, people will feel emotive about it and will care, we hope”

 

“And make it relevant to people in the UK and Europe and connect communities that are halfway across the world that have similarities and can work together to find a solution to our crazy plastic addiction”

 

 

 

 

 

 

Website – https://www.sailagainstplastic.com/

Blog – https://www.sailagainstplastic.com/blog-1/

Facebook – @amessagefromthearctic

Instagram – @amessagefromthearctic

Twitter – @Sail4seas

Art – Jess Grimsdale & Further info

 

Hosted by Ethan Wrigglesworth and Molly Meadows

Episode and show notes produced by Ben Toulson

 

#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!

 

My #ExeterMarine PhD: Marine Turtles of Brazil

Author – Lili Colman (PhD Student) – Centre for Ecology and Conservation, Penryn Campus

From the moment I arrived at the University of Exeter to undertake my MSc in Conservation and Biodiversity, I quickly fell in love with the University, the Campus and Cornwall. Discovering all the cutting-edge research being carried out across the University of Exeter has been a definite highlight for me. The opportunity to participate in the Africa field course was one of the most amazing experiences of my life and one I will always cherish, having helped me build a practical understanding of large-scale conservation issues. My MSc research project centred on analysing 30 years of mark-and-recapture data from juvenile green turtles on an isolated tropical archipelago in Brazil, under the supervision of Prof Brendan GodleyThis published work contributes important insights regarding demographic parameters and population trends for this species.

Lili_Kenya
Meeting the Maasai in Kenya

 

Upon my return to Brazil, and whilst working as an environmental consultant there, I applied for a PhD at Exeter to work with TAMAR (the Brazilian Sea Turtle Conservation Programme). This on-going conservation project illustrates a powerful example of how marine turtles and coastal communities can co-exist in an ever-changing world. Despite a history of over-exploitation, the five different species of marine turtles that nest in Brazil are now fully protected by law. And as a result, recent years have shown very promising signs of population recovery. Perhaps most notably, a major part of this success can be attributed to the active involvement of the surrounding coastal communities in the conservation work. What once started in the direct employment of former egg poachers, now involves a wide range of activities to encourage environmental awareness in the area. This includes environmental campaigns, alongside the support of alternative, sustainable economic opportunities for the communities living near the nesting beaches.

Tamar

Local kids talking turtle in Bahia, Brazil (Banco de imagens Projeto TAMAR)

My PhD research focuses on the highly migratory leatherback sea turtle (Dermochelys coriacea). This species has its major nesting site deep in the southwestern Atlantic ocean in eastern Brazil, on the northern coast of Espirito Santo. Projeto TAMAR has been monitoring the area since 1983 and there are promising signs of population recovery for the species. However, with a small population size and restricted geographical distribution, alongside the emergence of new threats – coastal development, fisheries bycatch, climate change, marine and light pollution – the population continues to be of conservation concern.

(Henrique Filgueiras)
Lili records leatherback sea turtle nesting (Henrique Filgueiras)

As part of the Marine Turtle Research Group (MTRG) at the University of Exeter, we are using a variety of techniques to investigate this population’s ecology, trends and the main impacts they are facing. This research is being done in collaboration with TAMAR in Brazil and Ciência Sem Fronteiras , a scholarship programme from the Brazilian Government. The knowledge obtained in this study will be used to design better and more effective conservation strategies for this species. I was delighted that my PhD project was chosen to feature in one of the films to celebrate TAMAR’s 35th anniversary:

#ExeterMarine is a 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!