Publications
Healing country together: A seagrass restoration case study from Gathaagudu (Shark Bay)
A successful seagrass restoration project in Shark Bay, Western Australia, demonstrates the power of integrating Western science with Indigenous traditional ecological knowledge. The partnership, involving the Malgana Aboriginal Corporation Ranger program, facilitated two-way knowledge sharing through On Country workshops, leading to effective restoration methods tailored for Gathaagudu. This collaboration not only restored seagrass ecosystems but also fostered cultural education, language preservation, and a deeper connection between people and their environment. The study highlights the potential of such partnerships to address long-standing restoration challenges while promoting holistic healing for both people and Country.
Assessing the Influence of HGT on the Evolution of Stress Responses in Microbial Communities from Shark Bay, Western Australia
Research at Shark Bay, Western Australia, reveals that horizontal gene transfer (HGT) has played a significant role in the evolution of stress response mechanisms in microbial communities inhabiting pustular mats. These mats serve as modern analogs of ancient microbial systems and are subject to various environmental stresses such as osmotic stress, oxidative stress, and arsenic toxicity. Using the MetaCHIP tool, scientists identified HGT events related to stress response genes in 83 metagenome-assembled genomes. Phylogenetic analyses suggest that these gene transfers may have occurred outside modern pustular mats, indicating a potentially long history of HGT. Notably, a specific osmoprotectant transport gene shows recent adaptations, hinting at interactions between Planctomycetota and Myxococcota within the mats. The findings underscore the ongoing microbial adaptations and evolution in these unique ecosystems.
Bidirectional fabric evolution in Hamelin Pool microbialites, Shark Bay, Western Australia
Researchers at Shark Bay, Western Australia, have uncovered bidirectional fabric evolution in microbialites within Hamelin Pool, revealing that these structures evolve both upward and downward as they grow. The study identified four accretionary mat types—pustular, smooth, colloform, and transitional—and demonstrated that while the surface mats change with water depth, subsurface microfabrics undergo a taphonomic progression from depositional architecture to micritic thickening and cement infilling. This bidirectional evolution suggests microbialites are not solely products of accretionary mat types but also result from early lithification processes, potentially enhancing their preservation in the geological record. The findings were derived from mesoscale and microscale observations, including polished slabs, thin section scans, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy.
Little change in surface sediment carbon stock following seagrass restoration in Shark Bay, Western Australia
A study on seagrass restoration in Shark Bay, Western Australia, reveals that surface sediment carbon stocks show little to no recovery up to five years after the restoration of Posidonia australis. Despite efforts to restore seagrass meadows, organic carbon concentrations and isotopic signatures (δ13C) in newly restored areas remained statistically indistinguishable from unvegetated sand. This suggests that carbon sequestration capacity does not return quickly even with successful seagrass reestablishment. The findings highlight the slow recovery of sediment carbon stocks following restoration efforts, with potential implications for climate change mitigation strategies relying on seagrass restoration.
Metagenomic, (bio)chemical, and microscopic analyses reveal the potential for the cycling of sulfated EPS in Shark Bay pustular mats
Research at Shark Bay, Western Australia, reveals that sulfated extracellular polymeric substances (EPS) play a significant role in microbial interactions and carbon cycling within ancient peritidal pustular mats. Metagenomic analysis identified cyanobacteria as the primary producers of these sulfated polysaccharides, while enzymes like sulfatases and glycosyl hydrolases, detected across multiple bacterial clades, indicate active degradation processes. Biochemical and microscopic analyses confirmed that sulfur abundance correlates with cyanobacterial presence, suggesting a dynamic cycle of synthesis, modification, and degradation that influences biomineralization and microbial community structure.
The microbial carbonate factory of Hamelin Pool, Shark Bay, Western Australia
Hamelin Pool, located in Shark Bay, Western Australia, functions as a modern microbial carbonate factory, offering critical insights into sedimentary deposits of microbial origin found in the geologic record. This study reveals that while the pool is renowned for its living marine stromatolites, erosion and degradation of weakly lithified microbial mats significantly contribute to the production and accumulation of sand-sized micritic grains. Comprehensive mapping shows that over 40 km² of upper intertidal shoreline and 20 km² of subtidal pavements are colonized by these mats, which erode to form irregular peloidal grains and platey micritic intraclasts. Together, these sediments make up nearly 26% of the total sediment in the pool, plausibly producing around 24,000 metric tons annually. This dual process of construction by lithifying microbial mats and erosion of weakly lithified mats provides a modern analog for ancient microbialite-micritic sediment facies associations.
Depositional timing and palaeoclimate interpretation of the Tamala Limestone aeolianites in Shark Bay, Western Australia
Paleoclimate reconstructions of Shark Bay reveal that the Tamala Limestone, a vast aeolian carbonate system along Western Australia's coast, was shaped by alternating glacial and interglacial intervals during the Pleistocene. Amino acid dating indicates units age eastward, while sedimentary breaks correlate with interglacial paleosols, suggesting prolonged aridity during glacial periods due to weakened Leeuwin Current and northward shifts in atmospheric circulation cells. This study combines stratigraphic and sedimentological analyses to demonstrate that lower sea levels and cooler Indo-Pacific Warm Pool temperatures coincided with drier conditions, while humid interglacials facilitated carbonate dissolution and paleosol formation.
Genome-resolved metagenomics provides insights into the functional complexity of microbial mats in Blue Holes, Shark Bay
A groundbreaking study reveals the functional complexity of microbial mats in Shark Bay's Blue Holes, uncovering diverse and potentially novel microorganisms, including members of DPANN, Asgard archaea, and candidate phyla radiation. These mats, thriving in hypersaline conditions, exhibit unique metabolic pathways, such as photoheterotrophy, and harbor a range of putative rhodopsins with uncharacterized functions. The research employed high-throughput metagenomic sequencing and hyperspectral confocal microscopy to analyze 117 medium- to high-quality metagenome-assembled genomes, identifying critical microbial interactions, viral defense mechanisms, elemental transport, osmoprotection, heavy metal resistance, and UV resistance. This study significantly enhances our understanding of these distinct mat systems and their adaptive responses.
Structure and function of Shark Bay microbial communities following tropical cyclone Olwyn: A metatranscriptomic and organic geochemical perspective
Tropical cyclones significantly alter microbial communities and geochemical processes in Shark Bay, Western Australia. Following Cyclone Olwyn (2015), black sludge deposits formed between microbialite columns, dominated by heterotrophic and anaerobic microbes like methanogens and sulfate-reducing bacteria. These microbes drove calcium carbonate precipitation, aiding mat preservation. Organic geochemical analysis revealed elevated C25 highly branched isoprenoid (HBI) alkenes, linked to cyclone-induced relocation of subtidal sediments containing HBI-producing diatoms. Additionally, sulfur-bound hopanoids and benzohopanes in mucilaginous cobbles suggested microbial matter influenced by cyclone-driven anoxia, promoting organic sulfurization. The study used metatranscriptomic and GC-MS analyses to uncover these post-cyclone changes.
A trial of transmitter attachment methods for Shark Bay bandicoots (Perameles bougainville)
Research on Shark Bay bandicoots (Perameles bougainville) demonstrates that collars, when fitted under general anaesthetic, provide the most effective and welfare-friendly method for monitoring these animals during reintroduction programs. The study found that collared bandicoots could be tracked for up to seven weeks with minimal harm, addressing a key challenge in post-release monitoring where alternative attachment methods often result in significantly shorter tracking durations.
Abundance estimates of Southern Hemisphere Breeding Stock ‘D’ humpback whales from aerial and land-based surveys off Shark Bay, Western Australia, 2008
Aerial and land-based surveys conducted off Shark Bay, Western Australia, in 2008 estimated the abundance of northward-migrating Southern Hemisphere Breeding Stock 'D' humpback whales at 34,290 (95% CI: 27,340–53,350), marking a 12.9% annual rate of increase since a 1999 estimate of 11,500. The study utilized single-platform aerial line transect and land-based surveys from Cape Inscription, Dirk Hartog Island, during the peak migration period (8–20 July). Practical challenges reduced the effectiveness of dual-survey approaches for estimating g(0), leading to alternative methods yielding higher estimates (around 0.6–0.7) and a conservative abundance estimate of 17,810 (14,210–27,720). The findings highlight significant growth in the population but also underscore methodological limitations in dual-survey techniques.
Discovery of an Abundance of Biosynthetic Gene Clusters in Shark Bay Microbial Mats
Researchers have uncovered a remarkable abundance of biosynthetic gene clusters (BGCs) in the microbial mats of Shark Bay, Western Australia. This discovery highlights the potential for microorganisms in extreme environments to produce secondary metabolites, which offer competitive advantages and biotechnological applications. The study identified 1477 BGCs across a 20 mm depth horizon, with the surface layer showing the highest relative abundance. Notably, terpene and bacteriocin BGCs were prominent, suggesting their significant roles in ecosystem function. Additionally, potentially novel BGCs were detected in Heimdallarchaeota and Lokiarchaeota, archaeal phyla not previously known to possess such clusters. This finding provides new insights into how secondary metabolites may enable microbial communities to adapt to harsh conditions.
Functional Gene Expression in Shark Bay Hypersaline Microbial Mats: Adaptive Responses
Microbial mats in Shark Bay, Western Australia, exhibit strong adaptive responses to hypersaline conditions, with gene transcription influenced by community structure and seasonality. The study reveals that these mats prioritize nutrient uptake—particularly fatty acids, phosphorus, iron, and nickel—and employ protective mechanisms against salinity and ammonium buildup. Key pathways for carbon cycling include anoxygenic photosynthesis and chemoautotrophy via the Arnon-Buchanan cycle, while smooth mats show enrichment in anaerobic processes like sulfate reduction and methanogenesis, reinforcing their role as modern analogs to ancient microbialites. This first metatranscriptomic analysis of actively growing hypersaline mats provides insights into their metabolic resilience and ecological significance.
A governance analysis of Ningaloo and Shark Bay Marine Parks, Western Australia: Putting the ‘eco’ in tourism to build resilience but threatened in long-term by climate change?
Climate change poses a significant long-term threat to the foundation species of Ningaloo and Shark Bay Marine Parks, despite their governance frameworks demonstrating world-leading effectiveness in addressing proximal impacts from local activities. A governance analysis using the MPA governance framework revealed that both parks employ diverse incentives that promote conservation objectives and equity, with highly evolved regulations leading to the stabilization or recovery of depleted fish stocks. However, challenges remain, including recreational fishing impacts, enforcement capacity, penalties for deterrence, cross-jurisdictional coordination, transparency in research, and tensions with the recreational fishing sector. While marine wildlife tourism governance is considered good practice, global action to mitigate climate change is critical for the long-term resilience of these iconic ecosystems.
Isolation of novel quorum-sensing active bacteria from microbial mats in Shark Bay Australia
Researchers have identified novel quorum-sensing active bacteria in the microbial mats of Shark Bay, Western Australia. The study, published in FEMS Microbiology Ecology, isolated 30 unique bacterial strains from a library of 165, belonging to Proteobacteria, Actinobacteria, and Firmicutes, which activated an AHL biosensor. Notably, several of these isolates, including members of Virgibacillus, Halobacillius, Microbacterium, and Brevibacterium, have not been previously shown to produce signal molecules. The presence of multiple signaling molecules was further confirmed using thin-layer chromatography (TLC). This is the first study to delineate AHL-based signaling in Shark Bay's microbial mats, suggesting that quorum sensing may play a significant role in coordinating complex phenotypes within these communities.
Sociality and tattoo skin disease among bottlenose dolphins in Shark Bay, Australia
A 34-year longitudinal study of bottlenose dolphins in Shark Bay, Australia, reveals that social associations with infected individuals significantly increase the risk of developing tattoo skin disease (TSD) in calves. The research demonstrates that calves with TSD in their second year of life were more likely to have associated with TSD-positive dolphins during their first year, unlike those without TSD. While metrics such as degree, time spent socializing, and group size did not show significant differences between infected and uninfected groups, the study highlights the epidemiological relevance of social network links in disease transmission. This finding underscores the potential of using social association networks to study the spread of skin diseases in bottlenose dolphins.
The Vulnerability of Microbial Ecosystems in a Changing Climate: Potential Impact in Shark Bay
Climate change poses significant threats to microbial ecosystems, including those in Shark Bay, Western Australia. Microorganisms, responsible for half of Earth's primary production and crucial to the survival of all macroscopic life, are highly vulnerable to changing environmental conditions such as extreme weather events, rising temperatures, sea levels, and ocean acidification. A review highlights that these changes could disrupt the delicate balance supporting microbial mats and stromatolites in Shark Bay, which are evolutionarily significant. The study emphasizes the need for focused research to understand the resilience of these ecosystems and to implement conservation strategies. It underscores the broader importance of including microorganisms in climate change discourse due to their pivotal role in both mitigating and exacerbating climate impacts.
Bioinformatic, phylogenetic and chemical analysis of the UV‐absorbing compounds scytonemin and mycosporine‐like amino acids from the microbial mat communities of Shark Bay, Australia
Research at Shark Bay, Western Australia, reveals that microbial mats in this UNESCO World Heritage Site produce UV-absorbing compounds—scytonemin and mycosporine-like amino acids (MAAs)—as a survival strategy against high radiation levels. The study found these photoprotective pigments are predominantly present in the upper layers of three distinct mat types: smooth, pustular, and tufted. Using advanced techniques like UV spectroscopy and mass spectrometry, scientists identified specific MAAs, including mycosporine-glycine and asterina, while also detecting an unknown MAA. Phylogenetic analysis linked scytonemin production to cyanobacteria abundance, highlighting its role in microbial resilience. This discovery underscores the adaptive mechanisms of Shark Bay’s microbial communities, offering insights into their ecological significance.
Comparative Metagenomics Provides Insight Into the Ecosystem Functioning of the Shark Bay Stromatolites, Western Australia
Comparative metagenomic analysis of stromatolites in Shark Bay, Western Australia, reveals two distinct processes of stromatolite formation dependent on water depth. Intertidal pustular mats exhibit enriched photosynthesis pathways, while subtidal colloform and smooth mats show increased heterotrophic metabolisms linked to carbonate mineralization, such as sulfate reduction. These findings highlight the adaptive strategies and synergistic microbial interactions that drive stromatolite accretion, providing insights into the ecosystem functioning of these ancient organosedimentary structures.
Disentangling the drivers of functional complexity at the metagenomic level in Shark Bay microbial mat microbiomes
A groundbreaking metagenomic analysis of Shark Bay's microbial mats reveals the functional complexity underlying its biogeochemical cycles, particularly carbon fixation via the Wood–Ljungdahl pathway. The study identified 87 medium-to-high-quality metagenome-assembled genomes (MAGs), including novel bins under the Asgard archaeal groups Thorarchaetoa and Lokiarchaeota. Key pathways for sulfur, nitrogen, phosphorus cycling, and environmental adaptation—such as UV resistance, hypersalinity tolerance, and heavy metal resistance—were mapped at a millimeter scale using shotgun sequencing on the Illumina NextSeq 500 platform. Over-representation of genes like those for sulfate assimilation, methanogenesis, and polyhydroxyalkanoate (PHA) synthase suggests specialized carbon storage and microbial interactions. The research also highlights putative viral defensive mechanisms, offering new models for how biogeochemical processes and adaptive responses partition in these extreme environments.
Exchange Flow Variability between Hypersaline Shark Bay and the Ocean
A steady, near-bed dense water outflow from Shark Bay’s northern Geographe Channel was observed for the first time, persisting through all tidal stages and exhibiting velocities 2–3 times stronger than previously recorded outflows in Naturaliste Channel. This outflow, driven by longitudinal density gradients, proved more resistant to tidal mixing, with turbulence peaking during flow reversals. The study identified tidal seabed flow as the primary source of turbulence, using bottom current speed cubed (|Ub³|) as a proxy for predicting dense water outflows. The Geographe Channel’s orientation and depth along the main density gradient axis explained its predominant outflow role, suggesting potential impacts on marine life recruitment, including commercially fished scallops and prawns.
Living Dendrolitic Microbial Mats in Hamelin Pool, Shark Bay, Western Australia
Hamelin Pool in Shark Bay, Western Australia, hosts the largest and most diverse living marine stromatolites, including seasonally ephemeral dendrolitic microbial mats. These modern structures, dominated by filamentous cyanobacteria like Lyngbya aestuarii, form shrub-like morphologies with thick 'trunks' and finer 'branches,' providing a rare opportunity to study dendrolite formation in real time. The research, conducted through an intensive field program, reveals the complex interplay between microbial communities and environmental factors, offering new insights into ancient microbialite structures preserved in the rock record.
Viral Communities of Shark Bay Modern Stromatolites
Shark Bay's modern stromatolites host abundant single-stranded DNA (ssDNA) viruses, with relative abundances mirroring those found in the Bahamas' Highbourne Cay. This is the first evidence of viral communities in these unique microbial structures, suggesting their global significance. The study used metagenomic shotgun sequencing to identify two putative viral genomes linked to the Genomoviridae family, potentially enriched by phi29-mediated amplification bias. Additionally, antiviral defense genes like CRISPR-Cas, BREX, and DISARM were found in the cellular fraction, a novel finding that may indicate microbial adaptation strategies. These viruses could play crucial roles in shaping microbial diversity and ecosystem function through infection and nutrient recycling.
Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes
A groundbreaking study reveals that microbial mats in Shark Bay, Australia, host distinct archaeal communities with significant differences between smooth and pustular mat structures. Smooth mats exhibit higher archaeal diversity, dominated by Parvarchaeota, while pustular mats are enriched with Halobacteria and Parvarchaeota. The research, employing high-throughput amplicon sequencing and biogeochemical analysis, found that methane production peaks in oxic layers of smooth mats, suggesting the presence of surface anoxic niches where anaerobic methanogens thrive despite high oxygen levels. This discovery challenges conventional understanding of microbial mat ecosystems and highlights the complex interplay between oxygen dynamics and archaeal metabolism.
Reintroduction of the greater stick-nest rat (Leporillus conditor) to Heirisson Prong, Shark Bay: an unsuccessful attempt to establish a mainland population
An attempt to re-establish the greater stick-nest rat (Leporillus conditor) on the mainland of Western Australia, after over 60 years of absence, proved unsuccessful despite efforts to mitigate predation. Forty-eight rats were translocated from Salutation Island to Heirisson Prong in Shark Bay between 1999 and 2001, with a focus on creating a predator-free refuge (17 ha) within a larger controlled area (1200 ha). While the rats dispersed beyond the refuge and showed signs of reproduction—with 28 recruits detected over eight years—the population declined steadily. Predation by monitors and small birds of prey within the refuge, along with feral cats outside it, likely contributed to the failure, compounded by an irruption of other rodents that increased predator pressure. Despite better mean condition than source populations, survivorship among later cohorts and recruits was significantly lower, highlighting the challenges of reintroduction in such ecosystems.
Captive Breeding of the Shark Bay Mouse Pseudomys fieldi to Facilitate Species Recovery in the Wild
A successful captive breeding program for the critically endangered Shark Bay Mouse (Pseudomys fieldi) at Perth Zoo produced 335 offspring from 93 litters, with an average litter size of 3.6 and year-round breeding observed. Sexual maturity was reached at 65 days, with the oldest recorded breeding female and male being 625 and 531 days old, respectively. The study highlights challenges in re-establishing reproduction after planned interruptions but provides a strategy to stimulate breeding and detailed husbandry methods. This program represents a critical step toward facilitating the recovery of this species in the wild.
Environmental Pressures Influencing Living Stromatolites in Hamelin Pool, Shark Bay, Western Australia
A study of Hamelin Pool, Shark Bay, reveals significant environmental pressures shaping the growth and morphology of living stromatolites. The research identifies regional trends of increasing salinity, greater temperature range, and decreasing energy moving southward from Faure Sill to the Nilemah Embayment, alongside seasonal paradoxes where salinities rise in wet winter months and drop in dry summer months. These patterns suggest groundwater influx along the Hamelin Pool shelf, potentially influencing stromatolite morphology, internal fabric, and microbial communities. The findings provide a framework for understanding extrinsic factors affecting stromatolites, offering insights into their development throughout Earth's history.
Integration of Cretaceous Morro do Chaves rock properties (NE Brazil) with the Holocene Hamelin Coquina architecture (Shark Bay, Western Australia) to model effective permeability
Effective permeability in coquina reservoirs, critical for pre-salt exploration in Brazil and Angola, is best estimated by integrating outcrop data with modern analogues. This study combines porosity and permeability measurements from a Cretaceous coquina bed in NE Brazil with the Holocene Hamelin Coquina architecture at Shark Bay, Western Australia, to model reservoir behavior. The research reveals that effective permeability lies between geometrical and harmonic averages of plug data, with moderate flow anisotropy favoring alignment along beach ridges. This approach improves reservoir characterization by leveraging both ancient outcrops and modern environments, offering a novel method for predicting fluid flow in coquina reservoirs.
New multi-scale perspectives on the stromatolites of Shark Bay, Western Australia
A recent intensive field program at Shark Bay, Western Australia, has revealed that coccoid cyanobacteria, not filamentous ones, dominate the microbial mats forming lithified stromatolite buildups, contradicting traditional views. This discovery was enabled by multi-scale mapping and molecular studies, which identified eight distinct 'Stromatolite Provinces' with unique geographic distributions of stromatolite structures. Additionally, analysis of internal fabrics showed pervasive microcrystalline carbonate precipitation in microbial mats, suggesting parallels with Precambrian stromatolites. These findings advance our understanding of benthic ecosystems on early Earth and provide a foundation for further studies on stromatolite morphogenesis.
Short-stop visitation in Shark Bay World Heritage Area: an importance–performance analysis
Visitors to Shark Bay World Heritage Area can achieve high satisfaction with natural attractions and educational facilities, even when visitor infrastructure is minimal. A study using importance-performance analysis (IPA) found that visitors to the stromatolite viewing-boardwalk in Hamelin Pool Marine Nature Reserve rated their experience positively despite limited facilities, highlighting the potential for short-stop tourism sites to thrive without extensive development. Visitors expressed a strong desire for updated interpretive signs or an educational mobile app, suggesting targeted improvements could enhance engagement. The IPA approach proved effective in identifying management priorities before implementing changes, offering a practical tool for sustainable tourism planning.
Mangrove-associated macroalgae and cyanobacteria in Shark Bay, Western Australia
Shark Bay, Western Australia, hosts a unique ecosystem where mangrove-associated macroalgae and cyanobacteria thrive under extreme conditions. This study reveals the diversity and ecological significance of these organisms, highlighting their resilience in high-salinity environments. Researchers employed field surveys, molecular analysis, and morphological examinations to document 123 species, including 58 cyanobacterial taxa, many of which were previously undocumented in the region. The findings underscore the importance of Shark Bay as a biodiversity hotspot, with implications for understanding microbial adaptation to extreme conditions and conserving its ecological uniqueness.
Niche differentiation of bacterial communities at a millimeter scale in Shark Bay microbial mats
Microbial mats in Shark Bay, Australia, exhibit distinct niche differentiation at millimeter scales, offering insights into early Earth ecosystems. The study revealed that smooth and pustular mat types harbor unique bacterial communities, with Cyanobacteria dominating the surface layers while deeper anoxic zones are dominated by Chloroflexi (smooth mats) or Alphaproteobacteria (pustular mats). High-throughput sequencing of 8.26 million 16S rRNA gene sequences identified 58 bacterial and candidate phyla, alongside biogeochemical measurements that showed smooth mats have steeper oxygen and hydrogen sulfide gradients, higher oxygen production, and sulfate reduction rates. Specific elements like molybdenum, magnesium, manganese, iron, vanadium, and phosphorus correlated with mat types and phylogenetic groups, suggesting surface anoxic niches, differential nitrogen fixation, and methane metabolism interactions.
Unravelling core microbial metabolisms in the hypersaline microbial mats of Shark Bay using high-throughput metagenomics
Shark Bay's hypersaline microbial mats, potential analogues of Earth's earliest ecosystems, exhibit unique metabolic pathways not found elsewhere. A first-of-its-kind shotgun metagenomic analysis revealed that these mats are dominated by Proteobacteria, Cyanobacteria, and Bacteroidetes, with distinct microbial community structures compared to Highbourne Cay (Bahamas). Notably, Shark Bay mats feature alternative non-rubisco-based carbon metabolism pathways, such as the reductive TCA cycle and 3-hydroxypropionate/4-hydroxybutyrate cycles, which are absent in other studied ecosystems. Additionally, evidence suggests novel nitrogen and heavy metal cycling processes involving arsenic, mercury, copper, and cadmium. Archaea, highly represented here, may play critical roles in ecosystem function, highlighting Shark Bay's microbial mats as unique and complex ecosystems warranting further study.
Organic geochemical studies of modern microbial mats from Shark Bay: Part I: Influence of depth and salinity on lipid biomarkers and their isotopic signatures
A study of microbial mats in Shark Bay, Western Australiarevealed that depth and salinity significantly influence lipid biomarkers and isotopic signatures. The research found that shallower mats exhibit higher diatom contributions, while deeper mats show increased seagrass-derived organic matter with 13C-depleted long-chain n-alkanes. Salinity variations also affect microbial communities, with high-salinity sites showing dominance of autotrophic biomass using distinct CO2 fixation pathways. The study analyzed lipid biomarkers (e.g., n-C17 and C25:1 HBI) and stable carbon isotopic values across four mat types along a tidal gradient, providing insights into the functional relationships between microbial communities and environmental conditions.
Stromatolite research in the Shark Bay World Heritage Area
Shark Bay, Western Australia, hosts some of the oldest living stromatolites on Earth, offering critical insights into ancient microbial ecosystems. Research by Collins and Jahnert (2014) highlights these stromatolites as unique biodiversity hotspots, contributing to our understanding of their ecological significance within UNESCO World Heritage Sites. The study employed field observations and environmental sampling to analyze the stromatolite communities, revealing their resilience in extreme conditions and their role in maintaining biodiversity. This work underscores the importance of protecting such sites for both scientific research and conservation efforts.
Active eukaryotes in microbialites from Highborne Cay, Bahamas, and Hamelin Pool (Shark Bay), Australia
A study of microbialites at Highborne Cay, Bahamas, and Hamelin Pool (Shark Bay), Australia, reveals significant novel eukaryotic diversity within these organosedimentary structures. Using RNA-based sequencing to focus on active organisms, researchers identified diverse communities dominated by stramenopiles, alveolates, metazoans, amoebozoans, and rhizarians, with many sequences showing less than 80% similarity to known GenBank entries. Notably, Hamelin Pool exhibited particularly high levels of novel eukaryotic diversity, possibly linked to its hypersaline conditions. The study also found vertical structuring in protist populations and highlighted greater foraminiferal diversity in bioturbated thrombolite mats at Highborne Cay, suggesting complex interactions between eukaryotes and sedimentary fabrics that may influence microbialite formation.
Characterizing the socially transmitted foraging tactic “sponging” by bottlenose dolphins ( Tursiops sp.) in the western gulf of Shark Bay, Western Australia
A study reveals that bottlenose dolphins (Tursiops sp.) in the western gulf of Shark Bay, Western Australia, employ a socially transmitted foraging tactic called 'sponging,' distinct from observations in the eastern gulf. This behavior, primarily exhibited by females in deep channel habitats, shows no significant difference in group associate numbers between spongers and non-spongers, unlike previous findings. Spongers were found to forage more frequently and rest less compared to deep-water non-spongers, suggesting variations in activity budgets. The research, conducted through 9 months of boat-based surveys over three field seasons, identified 40 individual spongers and provides insights into within-population foraging variations in bottlenose dolphins.
Controls on microbial activity and tidal flat evolution in Shark Bay, Western Australia
Shark Bay, Western Australia, hosts a unique microbial carbonate system shaped by extreme environmental conditions. The study reveals that microbial deposits, including stromatolites and thrombolitic forms, have evolved over the Holocene in response to sea-level variations and salinity changes. Nilemah tidal flat exhibits the thickest (1.3 m) and most developed microbial sedimentary system, with its deposition predating other flats like Rocky Point and Garden Point. The research identifies filamentous bacteria as dominant in tufted and smooth mats, while coccus bacteria dominate pustular and pavement structures. These microbial communities coexist with diverse organisms, contributing to extensive bioturbation and carbonate precipitation. The findings highlight the evolutionary series preserved within tidal flats, reflecting relative ages and salinity elevation.
Northernmost record of Shepherd’s beaked whale (Tasmacetus shepherdi) – a morphological and genetic description from a stranding from Shark Bay, Western Australia.
A dead Shepherd’s beaked whale (Tasmacetus shepherdi), a species with one of the least understood distributions among cetaceans, was found on a beach in Shark Bay, Western Australia, extending its known range northward to 26°20′S—the northernmost record for this species. Genetic analysis confirmed the identification, while age estimation via tooth dentine growth layers suggested the specimen was between 12 and 15 years old. This discovery challenges previous assumptions about T. shepherdi’s circumpolar distribution in temperate Southern Hemisphere waters (33°S–50°S) and provides critical data on its range, morphology, and genetics.
Source levels of dugong (Dugong dugon) vocalizations recorded in Shark Bay
Research in Shark Bay, Western Australia, reveals that dugongs (Dugong dugon) produce vocalizations with distinct source levels, ranging from 135 to 158 dB re 1 μPa at 1 m. These findings provide critical insights into the acoustic communication of dugongs, which are often active in shallow, turbid waters where visual cues are limited. The study used passive acoustic recording, a non-invasive method for detecting vocal marine animals, to estimate source levels for five call types: chirp (two variants), bark, squeak, and quack. Unlike traditional aerial surveys, this approach avoids logistical constraints and biases related to animal availability or perception. By analyzing recordings taken at 5.1 m from tagged dugongs in March 2012, the study offers a foundation for understanding the detection range of dugong calls, which could improve monitoring efforts for this vulnerable marine species.
Trawl impacts and biodiversity management in Shark Bay, Western Australia
A study on Shark Bay, Western Australia, reveals that environmental conditions play a more significant role in shaping faunal assemblages than trawl intensity. The research recorded 241 fish and 360 invertebrate species, with the top 20 most abundant species accounting for over 80% of fish and 88% of invertebrates caught. Depletion experiments showed varying catchability among species, suggesting that long-term trawl impacts can be mitigated by restricting trawling to current areas (20–40% of the fishery) and implementing daily vessel monitoring. This approach aims to ensure adherence to spatial and temporal closures for effective biodiversity management.
A comparative assessment of approaches and outcomes for seagrass revegetation in Shark Bay and Florida Bay
No single approach or technology guarantees cost-effective, scalable seagrass revegetation. A comparative study of projects targeting Posidonia australis and Amphibolis antarctica in Shark Bay (Western Australia) and Florida Bay found no consistent success factors despite evaluating anchoring techniques, plant density, and unit size. Short-term assessments (1–3 years), often driven by funding constraints, raise concerns about long-term ecological outcomes. Success depends on complex interactions among abiotic, biotic, and socioeconomic 'filters.' Future efforts must prioritize understanding these drivers, adopting proven methods, and implementing longer-term monitoring to ensure lasting ecological benefits.
Abundance, survival and temporary emigration of bottlenose dolphins (Tursiops sp.) off Useless Loop in the western gulf of Shark Bay, Western Australia
A study off Useless Loop in Shark Bay, Western Australia, estimated the abundance of Indo-Pacific bottlenose dolphins (Tursiops sp.) to range between 115 and 208 individuals from 2007 to 2011, with variability likely reflecting individual usage patterns rather than true population changes. Using capture–recapture models on photo-identification data collected during boat-based surveys, researchers found high temporary emigration rates (0.33–0.66), suggesting the study area did not encompass the full range of these dolphins. Apparent survival rates were estimated at 0.95 annually, indicating strong resilience in this population. This baseline data is critical for monitoring potential impacts from climate change or increased human activity on this UNESCO World Heritage Site.
Biology and management of a multi-sector blue swimmer crab fishery in a subtropical embayment – Shark Bay, Western Australia
A significant decline in the abundance of all size classes of blue swimmer crabs in Shark Bay, Western Australia, was observed following extreme environmental conditions linked to a strong La Niña event (2010–2011). Despite historical catch and effort data suggesting stability, this unexpected drop raises concerns about fishery sustainability. The study analyzed long-term commercial catch, trap monitoring, and trawl-survey data, revealing conflicting trends—stable legal catch rates but reduced large crab abundance. Preliminary findings suggest spawning stock levels were within historic ranges, but the causes of recruitment failure remain unclear. Management challenges include balancing latent effort (trap sector at 70–80% capacity) with the need for biological indicators to guide sustainable harvest strategies.
Carbon, nitrogen and phosphorus storage in subtropical seagrass meadows: examples from Florida Bay and Shark Bay
Seagrass meadows in Florida Bay and Shark Bay, Western Australia, store significant amounts of organic carbon and nutrients, with Shark Bay soils containing 21% more organic carbon and 35% more phosphorus than those in Florida Bay. Shark Bay also exhibits lower soil density, indicating a less compacted structure. Hypersaline regions in both bays show higher surficial soil organic carbon content. While Florida Bay's soil profiles suggest increased phosphorus delivery and primary productivity over the past century, Shark Bay's profiles indicate a decline in these factors over the last 1000 years. Despite differences, both bays rank among global hotspots for coastal ecosystem organic carbon storage, with Shark Bay storing an average of 243.0 MgCorg ha⁻¹ compared to Florida Bay's 163.5 MgCorg ha⁻¹.
Characterising the sources and fate of dissolved organic matter in Shark Bay, Australia: a preliminary study using optical properties and stable carbon isotopes
Shark Bay, a seagrass-dominated subtropical ecosystem with limited freshwater inputs, exhibits complex sources and transformations of dissolved organic matter (DOM). A study combining excitation/emission fluorescence spectroscopy (EEM-PARAFAC) and stable carbon isotope analysis revealed that DOM in Shark Bay originates from multiple sources, including terrestrial inputs, plankton, macroalgae, and seagrass. While isotopic data suggests substantial contributions from seagrass, fluorescence analysis indicates that much of this input is derived from decomposing detritus rather than active exudation during primary production. The study also highlights the role of evaporation in concentrating DOM and the potential significance of photo-degradation in transforming DOM within the system.
Characteristics, distribution and morphogenesis of subtidal microbial systems in Shark Bay, Australia
Extensive subtidal microbial deposits, covering approximately 300 km² of Hamelin Pool in Shark Bay, Australia, have been mapped and analyzed for the first time. These deposits, dominated by aragonite with distinctive isotopic signatures (δ13C +4.46 to +5.88; δ18O +3.06 to +3.88), reveal a subtidal microbial habitat 10 times larger than previously known intertidal areas. The study highlights two depositional stages, with growth rates ranging from <0.1 mm/year to 0.5 mm/year, and provides evidence of late Holocene sea-level changes through fabric sequences. Distinct microbial communities and lateral fabric relations were identified, emphasizing the geoscientific significance of Hamelin Pool for early life studies and ancient environmental interpretations.
Diversity of cyanobacterial biomarker genes from the stromatolites of Shark Bay, Western Australia
Research at Shark Bay's stromatolites reveals that cyanobacteria, not non-cyanobacterial species, dominate the production of 2-methylhopanoids—a key biomarker for tracing evolutionary history. This challenges previous assumptions by demonstrating that 11 out of 12 operational taxonomic units (OTUs) identified in microbial mats are cyanobacteria, based on phylogenetic analysis of the hpnP gene. The study analyzed genomic DNA from pustular and smooth microbial mats to construct an hpnP clone library, sequencing 117 partial clones. These findings clarify that cyanobacteria, not other bacteria, are the primary producers of this biomarker in Shark Bay's stromatolites, offering new insights into ancient microbial ecosystems.
Hydrogen sulfide intrusion in seagrasses from Shark Bay, Western Australia
Despite significant hydrogen sulfide (H₂S) intrusion into seagrass tissues—ranging from less than 20% to 100% in roots and rhizomes—no deleterious effects were observed in six seagrass species from Shark Bay, Western Australia. This finding contrasts with other coastal regions like Florida Bay, where sulfide toxicity has been linked to seagrass dieback. The study examined sulfide accumulation and anatomical differences in aerenchyma (air channels) and cell wall thickening, which may influence H₂S intrusion. While total sulfur accumulation varied among species, no consistent pattern emerged between larger, long-lived species and smaller, less persistent ones. Sediment sulfide concentrations were notably lower in Shark Bay than in Florida Bay, suggesting that current conditions may mitigate adverse effects.
Long-term monitoring of boat-based recreational fishing in Shark Bay, Western Australia: providing scientific advice for sustainable management in a World Heritage Area
A 12-year study of boat-based recreational fishing in Shark Bay, Western Australia, revealed that targeted management measures led to a significant 46% reduction in annual fishing effort between 1998 and 2010. This decline corresponded with decreased catches of pink snapper (Pagrus auratus), the key species, while the proportion of snapper released increased annually. The study also found that catches of other species declined but varied in composition. Conducted through 11 annual surveys at three boat ramps, this research demonstrated how long-term monitoring can provide critical data to assess and refine management strategies in a UNESCO World Heritage Area.
Nutrient status of seagrasses cannot be inferred from system-scale distribution of phosphorus in Shark Bay, Western Australia
Researchers found that phosphorus (P) availability for seagrasses in Shark Bay, Western Australia, cannot be predicted from large-scale sedimentary P distributions. Despite a known north-to-south gradient of P concentrations across the embayment, local-scale nutrient content in seagrass leaves (Amphibolis antarctica and Halodule uninervis) showed high variability and no strong correlation with sediment P levels. Mean nitrogen (N) to phosphorus (P) ratios (<33.5) also suggested that P limitation was unlikely, contrary to prior assumptions. The study concluded that P availability is likely a localized, complex interplay of nutrient inputs, delivery rates, and cycling dynamics, rather than a system-wide trend.
Performance of square-mesh codends in reducing discards and by-catch in the Shark Bay scallop fishery
A study on Shark Bay, Western Australia, found that square-mesh codends significantly reduce discards and by-catch in the saucer-scallop trawl fishery compared to conventional diamond-mesh codends. Specifically, 55- and 60-mm square-mesh codends retained 22–33% fewer small scallops (<85 mm shell height) while maintaining commercial-sized scallop catch rates and achieving up to a 95% reduction in by-catch. The 60-mm square-mesh codend also reduced prawn catch to less than 2% of that in standard prawn nets, suggesting potential for broader adoption in the fishery. This approach could improve net efficiency and water flow, benefiting both sustainability and commercial catches.
Recovery of inner Shark Bay snapper (Pagrus auratus) stocks: relevant research and adaptive recreational fisheries management in a World Heritage Property
A study on the recovery of snapper (Pagrus auratus) stocks in Shark Bay, Western Australia, reveals that adaptive recreational fisheries management has successfully rebuilt spawning biomass to target levels in the Eastern Gulf and Denham Sound, while the Freycinet Estuary shows slow but steady recovery. The research highlights the effectiveness of progressive management measures, including increased minimum length limits, maximum length restrictions, daily bag limit reductions, a moratorium, spawning closures, and a Total-Allowable-Catch system introduced between 1998 and 2003. These findings underscore the importance of data-driven, adaptive approaches in recreational fisheries management, particularly in UNESCO World Heritage Sites where both conservation and sustainable use are critical.
Science behind management of Shark Bay and Florida Bay, two P-limited subtropical systems with different climatology and human pressures
Shark Bay, Western Australia, and Florida Bay serve as critical case studies for understanding subtropical embayments with phosphorus-limited ecosystems. A recent compilation of research highlights the need for a more integrated, multidisciplinary approach to stewardship, addressing gaps in ecological resilience knowledge under increasing anthropogenic pressures. While individual studies provide valuable insights, they often lack cohesion, hindering effective management strategies. The research emphasizes the importance of studying interactions between physical environmental drivers and biological controls, such as behavioral and trophic dynamics, to enhance conservation efforts. Shark Bay's relatively pristine state offers a unique opportunity for large-scale, international collaborative studies that could inform broader marine conservation strategies.
Sea-level variation and the zonation of microbialites in Hamelin Pool, Shark Bay, Western Australia
Astronomical tides are not the primary driver of microbial zonation in Hamelin Pool, Shark Bay. Instead, seasonal oceanic cycles and short-term irregular variations dominate sea-level fluctuations, dictating the duration of immersion and exposure that shapes microbial community distribution. The study analyzed a 1983–1985 sea-level record using time-series analysis, revealing five key components: seasonal cycles, short-term irregularities, complex tidal systems, isolated major events, and wind-stress-induced variations. Microbial communities are stratified into three zones—Zone 3 (permanently submerged microbialite-forming mats), Zone 2 (lower littoral environments with exposed, colonized microbialites), and Zone 1 (ephemeral communities inundated only under exceptional conditions). This zonation is fundamentally controlled by seasonal cycles rather than tidal forces.
Seasonal, Spatial, and Postharvest Variability in the Survival of Repeatedly Discarded Saucer Scallops in Shark Bay, Western Australia
Saucer scallops (Amusium balloti) exhibit significantly higher survival rates when discarded during the postspawning winter months (>90%) compared to the prespawning summer months (20–90%), indicating that thermal stress from seasonal temperature differences is a critical factor in their resilience. A study using short-term tag-recapture experiments found no significant differences in survival based on fishing grounds or postcapture treatment, suggesting that current management practices—focusing regulatory discarding during winter when discard mortality is minimized—are more effective than pre-2004 regulations that mandated summer discarding, which likely led to higher mortalities. This research supports the existing strategy of prioritizing fishing during warmer prespawning months to reduce discard-related impacts on scallop populations.
Site specialists, diet generalists? Isotopic variation, site fidelity, and foraging by loggerhead turtles in Shark Bay, Western Australia
Loggerhead turtles in Shark Bay, Western Australia, exhibit strong site fidelity and remarkable affinity for small geographic areas, often less than 5 km², suggesting they are site specialists. While larger adults display low isotopic variance, indicating a highly generalized diet, smaller individuals show higher isotopic variation, potentially reflecting dietary differences or timing of habitat recruitment. This study integrates stable isotope analysis with behavioral data to infer foraging patterns, challenging the assumption that among-individual isotopic variation at nesting sites reflects prey specialization.
Tagging studies reveal restricted movement of snapper (Pagrus auratus) within Shark Bay, supporting fine-scale fisheries management
Snapper (Pagrus auratus) populations in Shark Bay, Western Australia, exhibit highly restricted movement, supporting the implementation of fine-scale fisheries management zones. A 1980s tagging study revealed that 300 out of 491 recaptures occurred within 5 nautical miles of the tagging site, with only 3.3% crossing a newly defined zone boundary. A follow-up study from 1998 to 2003, involving 2558 tagged snapper, confirmed this pattern, with 181 out of 197 recaptures happening at the tagging site. Juveniles were found to be more sedentary than adults, while adults showed limited evidence of inter-annual spawning-site fidelity. These findings support the use of three small management zones in Shark Bay's Western Gulf, aiding community acceptance through collaborative research efforts.
Variability in the spatial and temporal distribution of the saucer scallop, Amusium balloti, in Shark Bay – management implications
A study on the saucer scallop, Amusium balloti, in Shark Bay reveals significant annual variability in recruitment abundance and spatial distribution, primarily driven by environmental factors. This variability is critical for fishery management, as it influences catch rates and the effectiveness of fishing strategies. Geostatistical modeling was used to analyze survey data, demonstrating that high-abundance areas correlate with commercial catches, validating their use for optimizing fishing practices. The research also highlights the importance of retaining residual scallops to sustain the fishery, given their contribution to overall catch alongside recruits.
Habitat Use and Foraging Ecology of a Batoid Community in Shark Bay, Western Australia
In the pristine ecosystem of Shark Bay, Australia, batoid mesopredators—juvenile rays and skates—dominate nearshore habitats during warm seasons, suggesting their abundance is more influenced by predator avoidance than optimal foraging conditions. Stable isotopic analysis revealed high dietary overlap among species, with crustaceans from seagrass habitats as a primary food source, though individual specialization also occurs. Acoustic telemetry showed that batoids remain resident year-round but shift habitats seasonally rather than migrating, indicating their lower abundance in cold seasons is due to habitat preference rather than emigration. These findings challenge the assumption that mesopredator dynamics are solely regulated by prey availability and highlight the potential for seasonal ecosystem impacts through their presence, despite limited foraging activity on sandflats.
Why become speckled? Ontogeny and function of speckling in Shark Bay bottlenose dolphins ( Tursiops sp.) 1
Bottlenose dolphins in Shark Bay, Western Australia, develop speckled patterns on their ventral sides starting at around 10.2 years of age, with speckles increasing in number and density throughout their lifespan. This study, tracking 88 dolphins from birth to age 34, found that while the onset of speckling does not differ significantly by sex, it correlates with sexual maturity in females, particularly aligning with the age of first parturition. The research suggests that speckle patterns likely serve a communicative function rather than concealment, as predation risk and hunting success peak much earlier in life. This finding challenges traditional assumptions about color pattern functions in cetaceans and highlights the potential for ventral speckling to signal reproductive status or condition.
Spatial variation in life history characteristics of snapper ( Pagrus auratus ) within Shark Bay, Western Australia
Research in Shark Bay, Western Australia, reveals significant spatial variation in the life history traits of snapper (Pagrus auratus) at scales smaller than tens of kilometers. This study, conducted between 1997 and 2004, found differences in spawning season timing, duration, length and age at maturity, maximum age, and growth rates among populations from the Eastern Gulf, Denham Sound, and Freycinet Estuary. These variations were attributed to environmental conditions and density-dependent responses to fishing-induced changes in spawning biomass. The findings support the notion that local snapper stocks should be managed at fine geographic scales to safeguard both stock productivity and genetic diversity.
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