Publications

Journal article | Peer reviewed

From little things, big things grow: using applied nucleation to restore marine forests ↗

by Catalina A. Musrri, Georgina Wood, Adriana Vergés, Alexandra H. Campbell, Melinda A. Coleman, Sebastian Vadillo Gonzalez, Peter D. Steinberg and Ezequiel M. Marzinelli

14 May 2026
npj Ocean Sustainability

Global habitat degradation has prompted an urgent need for efficient restoration strategies at appropriate spatial scales. “Applied nucleation” is a restoration technique used in terrestrial forests, which starts with planting small vegetation patches that set the trajectory for natural propagation and recovery, resulting in large-scale restoration outcomes that require fewer resources. This concept could provide a framework for the restoration of marine seaweed forests, which are declining at unprecedented scales. We used the loss and 13-year restoration efforts of crayweed (Phyllospora comosa) forests along 70 km of Sydney’s coastline, Australia, to determine the feasibility and challenges of applied nucleation in marine forests. After transplanting events at 14 sites, 43% of transplanted sites led to the establishment and expansion of crayweed, covering ~19,000 m2 along Sydney’s coastline. Recruitment 9 months post-transplantation was negatively associated with grazing and positively related to survival of transplanted adults—a source of propagules and canopy cover in the short-term. In the longer term, crayweed expansion was positively associated with other canopy-forming seaweed species, suggesting canopy provision as an important factor influencing recovery. Small-scale efforts, such as applied nucleation, that consider factors influencing seaweed establishment and expansion can help re-establish marine forests at relevant scales.

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Journal article | Peer reviewed

Exploring the associations among halogenated compounds in Asparagopsis taxiformis: temporal shifts and bacterial impacts under intensive cultivation ↗

by S. Blanco-González, P.R. Brooks, D.A. Heyne, A.H. Campbell, S.F. Cummins and N.A. Paul

2026
Algal Research

Bromoform is the key antimethanogenic bioactive in Asparagopsis species, yet its variation in culture and relationship with other halogenated compounds remain poorly understood. Here, the profile of 9 halogenated compounds in A. taxiformis sporophytes cultured at 0.5 g/L over five weeks were quantified, comparing control cultures to those exposed to gentamicin (10 and 20 mg/L) which temporarily reduced surface bacteria by 81–95 %. Chemical analyses (n = 75) identified three classes of compounds (haloacids, halomethanes and haloacetones) comprising totals of 1–3.3 % dry weight (dw). Haloacids represented half the total; dibromoacetic acid (DBAA, 31.4 %), tribromoacetic acid (TBAA, 10 %) and bromochloroacetic acid (1.3 %). Halomethanes accounted for 39.5 % with bromoform (36.4 %) the single most abundant compound at 0.44–1.38 % dw. DBAA and TBAA concentrations reached 0.47–0.82 % and 0.13–0.38 % dw, respectively. Haloacetones contributed 10.7 % of the total, positively correlating with five other halogenated compounds. However, DBAA and TBAA concentrations correlated more closely to growth, cell morphology and bacterial densities than to other halogenated compounds. Overall, there was a temporal shift in growth rates for both antibiotic treatments – initially suppressing growth by 10–25 % before stabilising with all treatments converging to a specific growth rate of ~8.5 % day−1 by week 5. Extending the cultures for an additional 10 weeks confirmed no long-term impacts of antibiotic treatments on growth, halogenated compounds or the composition of surface bacterial community. This study is the first comprehensive evaluation of halogenated compound loads in cultured Asparagopsis, identifying TBAA as a major component that may contribute to antimethanogenic activity in ruminant feed.

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Journal article | Peer reviewed

Experimental and molecular observations associated with sub-lethal autotoxicity in cultivated Asparagopsis taxiformis following exudate accumulation ↗

by Stuart J.H. Smith, Nicholas A. Paul, Alexandra H. Campbell, Scott F. Cummins, Jianli Liu and Tomas Lang

2026
Algal Research

The farming of the red seaweed Asparagopsis taxiformis is expanding due to its ability to mitigate methane emissions from livestock when supplemented into cattle feed, with increasing focus on developing land-based, recirculating aquaculture systems to enhance production. The exudates of Asparagopsis are allelopathic towards a range of organisms; however, there remains a lack of data on the potential autotoxicity of exudate-derived metabolites from the A. taxiformis holobiont, which may have implications on the outcomes of land-based A. taxiformis aquaculture. To address this research gap, we conducted an omics-wide examination of conspecific allelopathy in the holobiont of A. taxiformis tetrasporophytes. Following a 5-day cultivation in seawater pre-conditioned with its own exudates, the growth rate of tetrasporophytes was dramatically reduced at some stocking densities compared to those in control seawater without pre-existing A. taxiformis exudates. An untargeted exometabolomic analysis identified that various peptide and amino acid-based compounds, alkaloids, terpenoids, and fatty acids were at least three to four times more abundant in cultures that experienced reduced growth, suggesting these compounds may be associated with autotoxicity-like effects. Furthermore, in cultures experiencing reduced growth, we detected increased expression of stress-related genes involved in the production and scavenging of reactive oxygen species (e.g. vanadium-dependent haloperoxidases, animal heme peroxidases and manganese superoxide dismutase). Altogether, our study provides the first characterisation of A. taxiformis secreted molecules, some of which may be considered autotoxicity candidates and further emphasises that regular water exchange or ultrafiltration is vital for successful cultivation of A. taxiformis in closed or low-exchange systems.

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Journal article | Peer reviewed

The microRNA Pathway of Macroalgae: Its Similarities and Differences to the Plant and Animal microRNA Pathways ↗

by Nicholas A. Paul, Scott F. Cummins, Andrew L. Eamens, Jessica Webb, Min Zhao and Alexandra H. Campbell

2025
Genes

In plants and animals, the microRNA (miRNA) class of small regulatory RNA plays an essential role in controlling gene expression in all aspects of development, to respond to environmental stress, or to defend against pathogen attack. This well-established master regulatory role for miRNAs has led to each protein-mediated step of both the plant and animal miRNA pathways being thoroughly characterized. Furthermore, this degree of characterization has led to the development of a suite of miRNA-based technologies for gene expression manipulation for fundamental research or for use in industrial or medical applications. In direct contrast, molecular research on the miRNA pathway of macroalgae, specifically seaweeds (marine macroalgae), remains in its infancy. However, the molecular research conducted to date on the seaweed miRNA pathway has shown that it shares functional features specific to either the plant or animal miRNA pathway. In addition, of the small number of seaweed species where miRNA data is available, little sequence conservation of individual miRNAs exists. These preliminary findings show the pressing need for substantive research into the seaweed miRNA pathway to advance our current understanding of this essential gene expression regulatory process. Such research will also generate the knowledge required to develop novel miRNA-based technologies for use in seaweeds. In this review, we compare and contrast the seaweed miRNA pathway to those well-characterized pathways of plants and animals and outline the low degree of miRNA sequence conservation across the polyphyletic group known as the seaweeds.

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Journal article | Peer reviewed

Insights into the Red Seaweed Asparagopsis taxiformis Using an Integrative Multi-Omics Analysis ↗

by Nicholas A. Paul, Scott F. Cummins, Min Zhao, Tomas Lang, Zubaida Patwary, Andrew L. Eamens, Tianfang Wang, Jessica Webb, Giuseppe C. Zuccarello, Ana Wegner-Thépot, Charlotte O’Grady, David Heyne, Lachlan McKinnie, Cecilia Pascelli, Nori Satoh, Eiichi Shoguchi and Alexandra H. Campbell

2025
Plants

The red seaweed Asparagopsis taxiformis (Bonnemaisoniaceae, Rhodophyta) produces a bioactive natural product, bromoform, which, when fed to ruminant livestock, can eradicate methane emissions. However, to cultivate enough A. taxiformis to produce a yield that would have a meaningful impact on global greenhouse gas emissions, we need to advance our current understanding of the biology of this seaweed species. Here, we used both a domesticated diploid tetrasporophyte (>1.5 years in culture) and wild samples to establish a high-quality draft nuclear genome for A. taxiformis (lineage 6 based upon phylogenetic analyses using the cox2-3 spacer). The constructed nuclear genome is 142 Mb in size (including 70.67% repeat regions) and was determined to encode for approximately 10,474 protein-coding genes, including those associated with secondary metabolism, photosynthesis, and defence. To obtain information regarding molecular differences between cultured and wild tetrasporophytes, we further explored differential gene expression relating to their different growth environments. Cultured tetrasporophytes, which contained a relatively higher level of bromoform compared to wild tetrasporophytes, demonstrated an enrichment of regulatory factors, such as protein kinases and transcription factors, whereas wild tetrasporophytes were enriched for the expression of defence and stress-related genes. Wild tetrasporophytes also expressed a relatively high level of novel secretory genes encoding proteins with von Willebrand factor A protein domains (named rhodophyte VWAs). Gene expression was further confirmed by proteomic investigation of cultured tetrasporophytes, resulting in the identification of over 400 proteins, including rhodophyte VWAs, and numerous enzymes and phycobiliproteins, which will facilitate future functional characterisation of this species. In summary, as the most comprehensive genomic resource for any Asparagopsis species, this resource for lineage 6 provides a novel avenue for seaweed researchers to interrogate genomic information, which will greatly assist in expediating production of Asparagopsis to meet demand by both aquaculture and agriculture, and to do so with economic and environmental sustainability.

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Grants

2 January 2026

ReVISIRR: Reusable Virtual Infrastructure for Scalable Image Recognition Research

University of the Sunshine Coast (Australia, Sunshine Coast) - UniSC
Grant no. 0980031013.

Rania Shibl, Vikki Schaffer, Mark Brown, Peter Embleton, Geoffrey Will, Sam Van Holsbeeck, Alexandra Campbell, Madaline Healey and Kathy Townsend

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20 February 2025

Supporting resilient and equitable food systems: oyster mariculture enterprises and an exploration of co-culture of seaweeds in coastal communities in Fiji and northern Australia

Australian Centre for International Agricultural Research (Australia, Canberra) - ACIAR
Grant no. FIS/2022/147.

Samantha Nowland, Alexandra Campbell, Wayne O'Connor, Paul Southgate and Libby Swanepoel

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16 February 2024 - 31 December 2024

Supporting the Development of Aquaculture in Sri Lanka

University of the Sunshine Coast (Australia, Sunshine Coast) - UniSC
Grant no. 0980028990.

Alexandra Campbell

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4 July 2024

Exploring Golden Kelp surviving and thriving at the warming edge

Advance Queensland (Australia, Brisbane)
Grant no. 0980028607.

Alexandra Campbell

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1 January 2023 - 30 April 2024

Towards rescuing Australia's declining underwater Golden Kelp forests

University of the Sunshine Coast (Australia, Sunshine Coast) - UniSC
Grant no. 0980027704.

Scott Cummins, Cecilia Pascelli, Rania Shibl, Nick Paul and Alexandra Campbell

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24 December 2021 - 22 December 2023

Nature-based solutions for prawn farm effluent using seaweed

Fisheries Research and Development Corporation (Australia, Canberra) - FRDC
Grant no. 0980027171.

Alexandra Campbell and Nick Paul

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3 March 2020 - 2 March 2023

Harnessing seaweed genes to mitigate methane emissions from livestock

Australian Research Council (Australia, Canberra) - ARC
Grant no. DP200103013.

Nick Paul, Min Zhao, Alexandra Campbell, Eiichi Shoguchi and Scott Cummins

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1 September 2022 - 12 December 2022

Empowering Sunshine Coast youth to take climate action through social media and seaweed restoration

Queensland Department of Environment and Science (Australia, Brisbane)
Grant no. 0980027770.

Alexandra Campbell and Margarietha de Villiers Scheepers

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30 November 2022

Restoring seaweed forests: Answering the SOS for QLDs underwater 'Golden Kelp' forests

Sea World (Australia, Southport)
Grant no. 0980027088.

Alexandra Campbell

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1 March 2020 - 1 November 2022

Seaweed production as a nutrient offset for Moreton Bay

Fisheries Research and Development Corporation (Australia, Canberra) - FRDC
Grant no. 0980025885.

Alexandra Campbell and Nick Paul

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Supervision

Doctoral Thesis Supervision - Completed

Human Dimensions and Environmental Benefits of Seaweed Farming and Restoration ↗

Students: Shelby Schumacher

Associated Researchers: Nick Paul, Alexandra Campbell and Libby Swanepoel

2021 - 5 March 2026

Seaweed is already one of the largest aquaculture crops globally. It is predicted to expand in developed countries, such as Australia, in the coming decades, providing both products (e.g., food, animal feed, nutraceuticals) and seedstock for the restoration of declining seaweed forests. In Australia, public acceptance and social licence for aquaculture can be contested, creating a barrier to new projects. Concurrently, scaled-up restoration of lost underwater seaweed forests will potentially rely on (i) contributions from citizen scientists, (ii) aquaculture. Therefore, it is essential to understand people's concerns, motivations, and benefits regarding the restorative aquaculture of seaweeds in developed countries, such as Australia, to enhance its sustainable development. Drawing on social licence to operate, ocean literacy, and marine identity perspectives, this thesis examines how participation is initiated, what motivates it, and what outcomes it produces for individuals and legitimacy. This thesis is structured across six interconnected chapters, each contributing unique insights into the human dimensions of seaweed restoration and the mechanisms that may help in driving public support of restorative seaweed aquaculture. To assess what is presently understood about aquaculture's environmental benefits and impacts, Chapter 1 reviews the literature. This chapter compares seaweed production to other types of aquacultures, highlighting its unique capacity to provide critical ecosystem services, such as carbon sequestration, nutrient cycling, and habitat restoration. This chapter also provides the foundation for this thesis and presents the conceptual framework that underpins the thesis. The framework proposes a pathway for a social licence for restorative seaweed aquaculture (e.g., legitimacy, trust, perceived value, and willingness to support). Chapter 2 details an experiment on recruiting citizen scientists via social media to assess the efficacy of different messaging strategies in encouraging individuals to engage with content or sign up as citizen scientists. A fully factorial experiment was conducted over an 18-day recruitment campaign period, using short-form videos to compare different messaging combinations (content with a focus on the environment, people or seaweed, with either a positive or negative ‘framing’), and engagement metrics (interactions, views, follows, etc) across three social media platforms (Instagram, TikTok and LinkedIn). The study found that user engagement was platform-specific, with more users (10-15 times) viewing content on TikTok than on Instagram or LinkedIn. However, LinkedIn and Instagram users interacted more meaningfully with the content, resulting in a greater impact. The results demonstrate that video ‘views’ do not necessarily translate into meaningful engagement, and that approximately 1% of participants who engage with online content may eventually sign up and participate in real-world restoration work as citizen scientists. Chapter 3 explored the demographic traits and motivations of people who signed up to volunteer as citizen scientists with the seaweed research group. This chapter examined the emotional drivers of participation, including the roles of emotions such as awe and wonder in fostering connection and pro-environmental behaviours, as well as climate change worry and identity. These findings offer insights into some of the factors that may be crucial for inspiring public engagement, which is essential for designing effective and inclusive restoration programs and citizen science recruitment campaigns that can underpin scaled-up restoration projects in the future. Chapter 4 evaluated the mental health and well-being benefits of participating in a seaweed restoration project on the Sunshine Coast by comparing the well-being survey responses of participants before, immediately after, and two weeks after participation. The findings revealed that active involvement in ecological restoration led to a significant increase in individuals' subjective nature connectedness (INS), which persisted for at least two weeks following the event and a reduction in feelings of stress and helplessness. These findings suggest that citizen science initiatives are not only good for the environment but also human mental well-being. Chapter 5: A systematic review was conducted to assess social attitudes towards aquaculture and ecological restoration, including the economic opportunities and enhanced community resilience that it can provide. Central to this chapter is the question of how attitudes towards aquaculture production and restoration differ globally, with a particular focus on comparisons between developed and developing countries, and how these attitudes might influence perceptions of seaweed restoration and hinder aquaculture development in Australia. This review helps to provide clarity on where legitimacy and acceptance dynamics converge or diverge across restoration and aquaculture, thus informing implications for social licence to operate for restorative aquaculture in Australia. Lastly, Chapter 6 synthesises findings from the previous five chapters, drawing connections between the ecological and social dimensions of restorative seaweed aquaculture and public participation. It highlights the importance of a multidisciplinary approach, combining environmental science, social psychology, and communication strategies to create scalable solutions for marine ecosystem restoration.

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Doctoral Thesis Supervision - Current

Harnessing seaweed genes to future-proof Golden Kelp forests for Australia

Students: Research student (name withheld)

Associated Researchers: Alexandra Campbell and Scott Cummins

2026

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Doctoral Thesis Supervision - Current

The potential for restorative aquaculture of subtropical Sargassum seaweeds.

Students: Research student (name withheld)

Associated Researchers: Alexandra Campbell and Nick Paul

2026

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Doctoral Thesis Supervision - Completed

Application of omics to elucidate the principles of interactions in the Asparagopsis taxiformis holobiont ↗

Students: Tomas Lang

Associated Researchers: Alexandra Campbell, Nick Paul and Scott Cummins

23 March 2021 - 14 April 2025

The addition of the red seaweed Asparagopsis taxiformis into cattle diet is a promising strategy to reduce methane emissions derived from cattle rumen. This is primarily attributed to bromoform, a halogenated compound which is stored by A. taxiformis in specialised vesicles (or gland cells) and can interfere with methane biosynthesis within rumen. Consequently, the farming of A. taxiformis is set to expand and the developments will likely include land-based cultures of A. taxiformis tetrasporophytes in closed systems. Nevertheless, despite the growing potential of A. taxiformis as an aquaculturally significant species, there are currently various bottlenecks that prevent its farming at large scale. One of these bottlenecks includes a lack of understanding, particularly at a molecular level, of the biology of this organism under culture conditions. Gaining such knowledge may be valuable for future A. taxiformis aquaculture developments and provides novel insights into the ecology of this widespread seaweed. Therefore, the main objective of this Thesis was to investigate the molecular principles of intraspecific interactions within the entire A. taxiformis holobiont (i.e. seaweed host and its associated microbiome).

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Doctoral Thesis Supervision - Completed

Bacterial influences on the culture and bioactive natural products of the red seaweed Asparagopsis taxiformis ↗

Students: Silvia Blanco Gonzalez

Associated Researchers: Alexandra Campbell, Nick Paul and Scott Cummins

2021 - 2025

Asparagopsis taxiformis has emerged as a natural feed additive for mitigating enteric methane through its halogenated metabolites, most notably bromoform. However, wide variability in bromoform content impedes reliable, large-scale cultivation to serve the 1.5 billion cattle in the world. Although >100 halogenated compounds have been identified in the genus, quantitative data on their interrelationships and the influence of surface-associated bacteria remain scarce. This thesis fills those gaps by examining how bacterial communities modulate growth rates and halogenated compounds profiles in cultured A. taxiformis. Across four chapters of bacterial manipulations and a metaanalysis, it develops a bacteria-driven enhancement of seaweed production and halogenated compounds.

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