Multidisciplinary research to understand and protect vital marine ecosystems.

“I am a marine biologist investigating the photosynthesis and biogeochemistry of coastal marine ecosystems, with the aim of better understanding ecosystem function and improving conservation actions.

“For as long as I can remember, I’ve always been fascinated by the sea, and as a county-level swimmer in my teens I have always had confidence in the water. Once I started my A-levels, my goal was to study marine science at university – I took time to look at the different degree programmes, made campus visits and talked to potential lecturers. I was able to gain a commercial SCUBA diver qualification as part of my undergraduate degree – although quite a significant time and financial commitment it was one of the best decisions I’ve made, as SCUBA diving has become a vital component of my research approach.

“I gained a BSc (Hons) degree in Ocean Science and an MSc in Applied Marine Science at the University of Plymouth before working at Plymouth Marine Laboratory for one year. From 2009-2013 I did a PhD at the University of Glasgow and Scottish Association for Marine Science, investigating sulphur cycling in maerl beds around the world. Following my PhD, I undertook a short postdoc at the University of Glasgow before moving to the University of St Andrews as an independent research fellow funded by the Marine Alliance for Science and Technology Scotland (MASTS). In 2015 I moved to Nature Microbiology as an Associate Editor, before joining the Lyell Centre at Heriot-Watt University, first as a Research Fellow, then Assistant Professor and now Associate Professor.

A smiling white woman with brown hair, wearing jeans and a sleeves white-and-navy striped shirt, with her right hand on her hip
Dr Heidi Burdett

Tumbleweed of the sea

“Our current research is centred around red coralline algae – commonly called maerl or rhodoliths. Maerl is a red seaweed that has a hard limestone skeleton and is completely free-living, rather like a ‘tumbleweed of the sea’. Aggregations of maerl create a reef-like habitat that has a complex three-dimensional structure. These so-called maerl or rhodolith beds are highly biodiverse, play a central role in coastal biogeochemical cycling and support several commercially important fish and bivalve species.

“Maerl beds are found throughout the world’s coastal oceans, so understanding the ecosystem function of this habitat has global significance. The northeast Atlantic, and Scotland in particular, is a European hotspot for maerl beds, but their survival is threatened by human disturbance, coastal development and climate change. It is becoming increasingly recognised that loss of this ecosystem would have devastating ecological and socioeconomic consequences around the globe. As such, maerl beds are of priority conservation concern at national-international levels and listed as ‘Vulnerable’ or ‘Endangered’ on the IUCN Habitats Red List, but remain poorly studied compared to other coastal habitats such as seagrass meadows or coral reefs. This limits the extent to which conservation decisions can be based on empirical scientific evidence. And this is something which I aim to overcome with my research.

Several SCUBA divers exploring a maerl bed on the ocean floor, with bubbles rising up through the water
Dr Heidi Burdett (front centre) on fieldwork in Fernando de Noronha, Brazil on a maerl bed 45 m below the ocean surface.

Seeing the light

“Multi-disciplinary collaborations are the key to pushing the boundaries of scientific advance. To accelerate that, I’ve been lucky enough to participate in both the Scottish and European Crucibles – research leadership programmes explicitly designed to encourage thinking ‘outside the box’ for new research ideas. Using a multi-disciplinary approach, our latest research projects have investigated the distribution, physiology and genetics of maerl beds. Maerl is one of the most cosmopolitan algal groups, with the capacity to live from the intertidal to hundreds of metres below the ocean surface, and from the poles to the equator. Using technical diving, we have been able to quantify the vast biodiversity of some of the deepest living maerl beds, almost 100 m below the ocean surface, showing that these deep-water beds may be vital in maintaining maerl bed biodiversity in the long-term.

“Working with experimental physicists, we have been able to define the light harvesting pathway of maerl – the first crucial step in photosynthesis when sunlight is first absorbed by the algae. Our results show with incredible temporal resolution (nanoseconds!) how maerl can adjust the composition of their light-harvesting complexes in response to both the colour and intensity of incoming light. Although we now know how maerl can survive low light environments, this comes at an energetic cost with slower growth rates and altered morphology. We have therefore been able to show that changes to the marine light environment (such as from pollution or land runoff) are vital considerations for maerl bed conservation.

“To support this, we have also used computer modelling to map maerl bed distribution around Scotland. In this digital space we were able to simulate projected climate change to 2100, finding that up to 84% of Scotland’s current maerl bed distribution may be lost. The resilience of maerl to climate change effects may be species-specific, and we are currently working on defining Scotland’s maerl genetic diversity to better resolve this. Regardless, the evidence – from us and others – suggests that maerl are severely threatened by projected climate change, with devastating consequences for biodiversity, carbon storage and fishery resources.

Long-term legacy

“To ensure that our research provides the information required by policymakers in a format that is digestible and relevant, we work with local policy stakeholders throughout the research process, including NatureScot, the Guernsey Biological Records Centre and the Parque Nacional Marinho de Fernando de Noronha (Brazil). We also work a lot in the public engagement of marine science to increase ocean literacy of children, their families and their educators. We have led many events for children, school-leavers and adults, participated in science festivals around the country and regularly work with journalists to maximise the reach of our research beyond academia.

“Over several years of collaboration, this has resulted in our research directly informing new conservation management decisions (such as revised marine protected area boundaries) and sustainable behaviour change that will ultimately increase the likelihood of a long-term legacy for maerl beds as a functionally important coastal habitat.”

Dr Heidi Burdett is an Associate Professor of marine ecosystem science at the Lyell Centre, Heriot-Watt University. Her recent research has been supported by the Natural Environment Research Council, the Leverhulme Trust and the British Phycological Society. Find out more here.

This post is part of a series showcasing Scotland’s innovative, high-impact research supporting biodiversity conservation, in partnership with Scottish Government and NatureScot. Read the rest of the series here.

Further reading

Turner, J.A., et al. 2019. Key questions for research and conservation of mesophotic coral ecosystems and temperate mesophotic ecosystems. Pp. 989—1003 in Loya, Y., Puglise, K., Bridge, T.(eds.) Mesophotic Coral Ecosystems. Coral Reefs of the World, vol 12. Springer, Cham.

Mao, H., et al. 2020. Carbon burial over the last four millennia is regulated by both climatic and land use change. Global Change Biology 26(4): 2496–2505.

Simon Nutbrown, C., et al. 2020. Species distribution modeling predicts significant declines in coralline algae populations under projected climate change with implications for conservation policy. Frontiers in Marine Science 7: 575825.

Jenkins, T.L., et al. 2021. Whole genome genotyping reveals discrete genetic diversity in north‐east Atlantic maerl beds. Evolutionary Applications 14(6): 1558—1571. Montseny, M., et al. 2021. Active ecological restoration of cold-water corals: techniques, challenges, costs and future directions. Frontiers in Marine Science 8: 621151.

Voerman, S.E., et al. 2022. Ecosystem engineer morphological traits and taxon identity shape biodiversity across the euphotic–mesophotic transition. Proc. R. Soc. B. 289(1969).