Physical Sciences and Mathematics Commons^™

Environmental Dna Identifies Coastal Plant Community Shift 1,000 Years Ago In Torrens Island, South Australia, Nicole R. Foster, Alice R. Jones, Oscar Serrano, Anna Lafratta, Paul S. Lavery, Kor-Jent Van Dijk, Ed Biffin, Bronwyn M. Gillanders, Jennifer Young, Pere Masque, Patricia S. Gadd, Geraldine E. Jacobsen, Atun Zawadzki, Andria Greene, Michelle Waycott

Research outputs 2022 to 2026

Anthropogenic activities are causing detrimental changes to coastal plants– namely seagrass, mangrove, and tidal marshes. Looking beyond recent times to past vegetation dynamics is critical to assess the response and resilience of an environment to change. Here, we develop a high-resolution multi-proxy approach, providing a new evidence base to decipher long-term change in coastal plant communities. Combining targeted environmental DNA analysis with chemical analysis of soils, we reconstructed 4,000 years of change at a temperate wetland on Torrens Island South Australia and identified an ecosystem shift that occurred ~ 1000 years ago. What was once a subtidal seagrass system shifted …

Influence Of The Atlantic Inflow On Trace Metal Enrichments In Sediments And Particulate Matter Of The Nw Alboran Sea (Sw Mediterranean), Albert Palanques, Pere Puig, Pere Masqué, Enrique Isla

Research outputs 2022 to 2026

Trace metal contents and fluxes in downward particulate matter and dated sediment cores of the NW Alboran Sea are analysed in this study with the aim of assessing the role of the Atlantic inflow on their transport. Increases in Zn, Cu and Pb were detected in downward particulate matter collected by sediment traps after river flooding events and after the Aznalcollar mining spill. Their arrival coincided within the recently estimated time range for river particles discharged into the Gulf of Cádiz to reach the Alboran Sea, indicating that their transfer is enhanced during events of increased river inputs of contaminated …

A 2,000-Year Record Of Eelgrass (Zostera Marina L.) Colonization Shows Substantial Gains In Blue Carbon Storage And Nutrient Retention, Martin Dahl, Martin Gullström, Irene Bernabeu, Oscar Serrano, Carmen Leiva-Dueñas, Hans W. Linderholm, Maria E. Asplund, Mats Björk, Tinghai Ou, J. Robin Svensson, Elinor Andrén, Thomas Andrén, Sanne Bergman, Sara Braun, Anneli Eklöf, Zilvinas Ežerinskis, Andrius Garbaras, Petter Hällberg, Elin Löfgren, Malin E. Kylander, Pere Masqué, Justina Šapolaitė, Rienk Smittenberg, Miguel A. Mateo

Research outputs 2022 to 2026

Assessing historical environmental conditions linked to habitat colonization is important for understanding long-term resilience and improving conservation and restoration efforts. Such information is lacking for the seagrass Zostera marina, an important foundation species across cold-temperate coastal areas of the Northern Hemisphere. Here, we reconstructed environmental conditions during the last 14,000 years from sediment cores in two eelgrass (Z. marina) meadows along the Swedish west coast, with the main aims to identify the time frame of seagrass colonization and describe subsequent biogeochemical changes following establishment. Based on vegetation proxies (lipid biomarkers), eelgrass colonization occurred about 2,000 years ago after geomorphological changes …

A Global Database Of Dissolved Organic Matter (Dom) Concentration Measurements In Coastal Waters (Coastdom V1), Christian Lønborg, Cátia Carreira, Gwenaël Abril, Susana Agustí, Valentina Amaral, Agneta Andersson, Javier Arístegui, Punyasloke Bhadury, Mariana B. Bif, Alberto V. Borges, Steven Bouillon, Maria L. I. Calleja, Luiz C. Cotovicz, Stefano Cozzi, Maryló Doval, Carlos M. Duarte, Bradley Eyre, Cédric G. Fichot, E. Elena García-Martín, Alexandra Garzon-Garcia, Michele Giani, Rafael Gonçalves-Araujo, Renee Gruber, Dennis A. Hansell, Fuminori Hashihama, Ding He, Johnna M. Holding, William R. Hunter, J. Severino P. Ibánhez, Valeria Ibello, Shan Jiang, Guebuem Kim, Katja Klun, Piotr Kowalczuk, Atsushi Kubo, Choon-Weng Lee, Cláudia B. Lopes, Federica Maggioni, Paolo Magni, Celia Marrase, Patrick Martin, S. Leigh Mccallister, Roisin Mccallum, Patricia M. Medeiros, Xosé A. G. Morán, Frank E. Muller-Karger, Allison Myers-Pigg, Marit Norli, Joanne M. Oakes, Helena Osterholz, Hyekyung Park, Maria L. Paulsen, Judith A. Rosentreter, Jeff D. Ross, Digna Rueda-Roa, Chiara Santinelli, Yuan Shen, Eva Teira, Tinkara Tinta, Guenther Uher, Masahide Wakita, Nicholas Ward, Kenta Watanabe, Yu Xin, Youhei Yamashita, Liyang Yang, Jacob Yeo, Huamao Yuan, Qiang Zheng, Xosé A. Álvarez-Salgado

Research outputs 2022 to 2026

Measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) concentrations are used to characterize the dissolved organic matter (DOM) pool and are important components of biogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOM v1; available at 10.1594/PANGAEA.964012, Lonborg et al., 2023) compiling previously published and unpublished measurements of DOC, DON, and DOP in coastal waters. These data are complemented by hydrographic data such as temperature and salinity and, to the extent possible, other biogeochemical variables (e.g. chlorophyll a, inorganic nutrients) and the inorganic carbon system (e.g. dissolved inorganic carbon …

Local Habitat Composition And Complexity Outweigh Seascape Effects On Fish Distributions Across A Tropical Seascape, Molly Moustaka, Richard D. Evans, Gary A. Kendrick, Glenn A. Hyndes, Michael V. W. Cuttler, Tahlia J. Bassett, Michael J. O’Leary, Shaun K. Wilson

Research outputs 2022 to 2026

Context: The distribution of animals is influenced by a complex interplay of landscape, environmental, habitat, and anthropogenic factors. While the effects of each of these forces on fish assemblages have been studied in isolation, the implications of their combined influence within a seascape remain equivocal. Objectives: We assessed the importance of local habitat composition, seascape configuration, and environmental conditions for determining the abundance, diversity, and functional composition of fish assemblages across a tropical seascape. Methods: We quantified fish abundance in coral, macroalgal, mangrove, and sand habitats throughout the Dampier Archipelago, Western Australia. A full-subsets modelling approach was used that incorporated …

Region-Specific Drivers Cause Low Organic Carbon Stocks And Sequestration Rates In The Saltmarsh Soils Of Southern Scandinavia, Carmen Leiva-Dueñas, Anna E. L. Graversen, Gary T. Banta, Jeppe N. Hansen, Marie L. K. Schrøter, Pere Masqué, Marianne Holmer, Dorte Krause-Jensen

Research outputs 2022 to 2026

Saltmarshes are known for their ability to act as effective sinks of organic carbon (OC) and their protection and restoration could potentially slow down the pace of global warming. However, regional estimates of saltmarsh OC storage are often missing, including for the Nordic region. To address this knowledge gap, we assessed OC storage and accumulation rates in 17 saltmarshes distributed along the Danish coasts and investigated the main drivers of soil OC storage. Danish saltmarshes store a median of 10 kg OC m−2 (interquartile range, IQR: 13.5–7.6) in the top meter and sequester 31.5 g OC m−2 yr−1 (IQR: 41.6–15.7). …

Global Dataset Of Soil Organic Carbon In Tidal Marshes, Tania L. Maxwell, André S. Rovai, Maria F. Adame, Janine B. Adams, José Álvarez-Rogel, William E. N. Austin, Kim Beasy, Francesco Boscutti, Michael E. Böttcher, Tjeerd J. Bouma, Richard H. Bulmer, Annette Burden, Shannon A. Burke, Saritta Camacho, Doongar R. Chaudhary, Gail L. Chmura, Margareth Copertino, Grace M. Cott, Christopher Craft, John Day, Carmen B. De Los Santos, Lionel Denis, Weixin Ding, Joanna C. Ellison, Carolyn J. E. Lewis, Luise Giani, Maria Gispert, Swanne Gontharet, José A. González-Pérez, M. Nazaret González-Alcaraz, Connor Gorham, Anna E. L. Graversen, Anthony Grey, Roberta Guerra, Qiang He, James R. Holmquist, Alice R. Jones, José A. Juanes, Brian P. Kelleher, Karen E. Kohfeld, Dorte Krause-Jensen, Anna Lafratta, Paul S. Lavery, Edward A. Laws, Carmen Leiva-Dueñas, Pei S. Loh, Catherine E. Lovelock, Carolyn J. Lundquist, Peter I. Macreadie, Inés Mazarrasa, J. Patrick Megonigal, Joao M. Neto, Juliana Nogueira, Michael J. Osland, Jordi F. Pagès, Nipuni Perera, Eva-Maria Pfeiffer, Thomas Pollmann, Jacqueline L. Raw, María Recio, Ana C. Ruiz-Fernández, Sophie K. Russell, John M. Rybczyk, Marek Sammul, Christian Sanders, Rui Santos, Oscar Serrano, Matthias Siewert, Craig Smeaton, Zhaoliang Song, Carmen Trasar-Cepeda, Robert R. Twilley, Marijn Van De Broek, Stefano Vitti, Livia V. Antisari, Baptiste Voltz, Christy N. Wails, Raymond D. Ward, Melissa Ward, Jaxine Wolfe, Renmin Yang, Sebastian Zubrzycki, Emily Landis, Lindsey Smart, Mark Spalding, Thomas A. Worthington

Research outputs 2022 to 2026

Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM). The MarSOC dataset includes 17,454 data points from 2,329 unique locations, and 29 countries. We generated a general transfer function for the conversion of SOM to SOC. Using this …

Substantial Blue Carbon Sequestration In The World’S Largest Seagrass Meadow, Chuancheng Fu, Sofia Frappi, Michelle N. Havlik, Wells Howe, S. David Harris, Elisa Laiolo, Austin J. Gallagher, Pere Masqué, Carlos M. Duarte

Research outputs 2022 to 2026

Seagrass meadows are important sinks for organic carbon and provide co-benefits. However, data on the organic carbon stock in seagrass sediments are scarce for many regions, particularly The Bahamas, which accounts for up to 40.7% of the documented global seagrass area, limiting formulation of blue carbon strategies. Here, we sampled 10 seagrass meadows across an extensive island chain in The Bahamas. We estimate that Bahamas seagrass meadows store 0.42–0.59 Pg organic carbon in the top-meter sediments with an accumulation rate of 2.1–2.9 Tg annually, representing a substantial global blue carbon hotspot. Autochthonous organic carbon in sediments decreased from ~1980 onwards, …

Gut Microbial Communities Of Hybridising Pygmy Angelfishes Reflect Species Boundaries, Megan J. Huggett, Jean-Paul A. Hobbs, Federico Vitelli, Michael Stat, Tane H. Sinclair-Taylor, Michael Bunce, Joseph D. Dibattista

Research outputs 2022 to 2026

Hybridisation and introgression of eukaryotic genomes can generate new species or subsume existing ones, with direct and indirect consequences for biodiversity. An understudied component of these evolutionary forces is their potentially rapid effect on host gut microbiomes, and whether these pliable microcosms may serve as early biological indicators of speciation. We address this hypothesis in a field study of angelfishes (genus Centropyge), which have one of the highest prevalence of hybridisation within coral reef fish. In our study region of the Eastern Indian Ocean, the parent fish species and their hybrids cohabit and display no differences in their diet, behaviour, …

Ocean Connectivity And Habitat Characteristics Predict Population Genetic Structure Of Seagrass In An Extreme Tropical Setting, Udhi E. Hernawan, Kor-Jent Van Dijk, Gary A. Kendrick, Ming Feng, Oliver Berry, Christopher Kavazos, Kathryn Mcmahon

Research outputs 2022 to 2026

Understanding patterns of gene flow and processes driving genetic differentiation is important for a broad range of conservation practices. In marine organisms, genetic differentiation among populations is influenced by a range of spatial, oceanographic, and environmental factors that are attributed to the seascape. The relative influences of these factors may vary in different locations and can be measured using seascape genetic approaches. Here, we applied a seascape genetic approach to populations of the seagrass, Thalassia hemprichii, at a fine spatial scale (~80 km) in the Kimberley coast, western Australia, a complex seascape with strong, multidirectional currents greatly influenced by extreme …

Decline Of Seagrass (Posidonia Oceanica) Production Over Two Decades In The Face Of Warming Of The Eastern Mediterranean Sea, Victoria Litsi-Mizan, Pavlos T. Efthymiadis, Vasilis Gerakaris, Oscar Serrano, Manolis Tsapakis, Eugenia T. Apostolaki

Research outputs 2022 to 2026

* The response of Posidonia oceanica meadows to global warming of the Eastern Mediterranean Sea, where the increase in sea surface temperature (SST) is particularly severe, is poorly investigated. * Here, we reconstructed the long-term P. oceanica production in 60 meadows along the Greek Seas over two decades (1997–2018), using lepidochronology. We determined the effect of warming on production by reconstructing the annual and maximum (i.e. August) SST, considering the role of other production drivers related to water quality (i.e. Chla, suspended particulate matter, Secchi depth). * Grand mean (±SE) production across all sites and the study period was 48 …

Drone Images Afford More Detections Of Marine Wildlife Than Real-Time Observers During Simultaneous Large-Scale Surveys, Amanda J. Hodgson, Nat Kelly, David Peel

Research outputs 2022 to 2026

There are many advantages to transitioning from conducting marine wildlife surveys via human observers onboard light-aircraft, to capturing aerial imagery using drones. However, it is important to maintain the validity of long-term data series whilst transitioning from observer to imagery surveys. We need to understand how the detection rates of target species in images compare to those collected from observers in piloted aircraft, and the factors influencing detection rates from each platform. We conducted trial ScanEagle drone surveys of dugongs in Shark Bay, Western Australia, covering the full extent of the drone’s range (∼100 km), concurrently with observer surveys, with …

Coastal Groundwater-Dependent Ecosystems Are Falling Through Policy Gaps, Madeleine Dyring, Melissa M. Rohde, Ray Froend, Harald Hofmann

Research outputs 2022 to 2026

Coastal groundwater-dependent ecosystems (GDEs), such as wetlands, estuaries and nearshore marine habitats, are biodiversity hotspots that provide valuable ecosystem services to society. However, coastal groundwater and associated ecosystems are under threat from groundwater exploitation and depletion, as well as climate change impacts from sea-level rise and extreme flood and drought events. Despite many well-intentioned policies focused on sustainable groundwater use and species protection, coastal GDEs are falling through gaps generated by siloed policies and as a result, are declining in extent and ecological function. This study summarized then examined policies related to the management of coastal groundwater and connected ecosystems …

Flaws In The Methodologies For Organic Carbon Analysis In Seagrass Blue Carbon Soils, Oscar Serrano, Ines Mazarrasa, James W. Fourqurean, Eduard Serrano, Jeffrey Baldock, Jonathan Sanderman

Research outputs 2022 to 2026

The ability to accurately measure organic carbon (OC) in marine sediments or soils is overall taken for granted in scientific communities, yet this seemingly mundane task remains a methodological challenge when the soil matrix contains calcium carbonate (CaCO3), creating inaccuracies in Blue Carbon estimates. Here, we compared five common methods combining acidification, combustion, and wet oxidation pre-treatments for determination of OC in sediments and soils containing CaCO3 based on the analyses of artificial soil mixtures made of different OC and CaCO3 contents, and multiple soils from Australian seagrass cores. The results obtained showed that methods involving acidification pre-treatment entailed −17 …

Methane Emissions In Seagrass Meadows As A Small Offset To Carbon Sequestration, Yvonne Y. Y. Yau, Gloria Reithmaier, Caludia Majtényi-Hill, Oscar Serrano, Nerea Piñeiro-Juncal, Martin Dahl, Miguel A. Mateo, Stefano Bonaglia, Isaac R. Santos

Research outputs 2022 to 2026

Seagrass meadows are effective carbon sinks due to high primary production and sequestration in sediments. However, methane (CH4) emissions can partially counteract their carbon sink capacity. Here, we measured diffusive sediment-water and sea-air CO2 and CH4 fluxes in a coastal embayment dominated by Posidonia oceanica in the Mediterranean Sea. High-resolution timeseries observations revealed large spatial and temporal variability in CH4 concentrations (2–36 nM). Lower sea-air CH4 emissions were observed in an area with dense seagrass meadows compared to patchy seagrass. A 6%−40% decrease of CH4 concentration in the surface water around noon indicates that photosynthesis likely limits CH4 fluxes. Sediments …

Seagrass Posidonia Escarpments Support High Diversity And Biomass Of Rocky Reef Fishes, Oscar Serrano Gras, Karina Inostroza, Glenn Hyndes, Alan M. Friedlander, Eduard Serrano, Caitlin Rae, Enric Ballesteros

Research outputs 2022 to 2026

Although seagrass meadows form a relatively homogenous habitat, escarpments, which form three-dimensional structures and originate from the erosion of seagrass peat, can provide important habitat for reef fishes. Here, we compare fish assemblages and habitat structural complexity among seagrass Posidonia australis escarpments and canopies, as well as limestone reef habitats, to understand the role of seagrass escarpments as reef fish habitat in Shark Bay, Western Australia. The total number of fish species, fish biomass, and top predator biomass were significantly higher in seagrass escarpments and reef habitats than in seagrass canopies due to lower habitat structural complexity and thus becoming …

The Risk Of Multiple Anthropogenic And Climate Change Threats Must Be Considered For Continental Scale Conservation And Management Of Seagrass Habitat, Kathryn Mcmahon, Kieryn Kilminster, Robert Canto, Chris Roelfsema, Mitchell Lyons, Gary A. Kendrick, Michelle Waycott, James Udy

Research outputs 2022 to 2026

Globally marine-terrestrial interfaces are highly impacted due to a range of human pressures. Seagrass habitats exist in the shallow marine waters of this interface, have significant values and are impacted by a range of pressures. Cumulative risk analysis is widely used to identify risk from multiple threats and assist in prioritizing management actions. This study conducted a cumulative risk analysis of seagrass habitat associated with the Australian continent to support management actions. We developed a spatially explicit risk model based on a database of threats to coastal aquatic habitat in Australia, spanning 35,000 km of coastline. Risk hotspots were identified …

Synthesis Report: Defining Thresholds And Indicators Of Primary Producer Response To Dredging-Related Pressures: Report Of Theme 5 Prepared For The Dredging Science Node, Paul Lavery, Kathryn Mcmahon, John Statton, Mat Vanderklift, Simone Strydom, Gary Kendrick

Research outputs 2014 to 2021

Seagrasses form a small component of a diverse group of organisms termed ‘benthic primary producers’. Benthic primary producers are organisms that grow on the sea-bed that obtain some or all of their energy needs from photosynthesis. This includes animals such as scleractinian corals and some sponges that host microscopic intercellular algae, coralline and turf algae, and the larger seaweeds such as the kelps and sargassum. Seagrasses are marine flowering plants, more closely related to land plants than seaweeds and algae. Seagrasses live mostly in soft sediments, and can be found from the shallow intertidal zone through to a depth of …

Seagrass Soil Archives Reveal Centennial-Scale Metal Smelter Contamination While Acting As Natural Filters, Anna Lafratta, O Serrano, Pere Masque, Miguel Mateo, Milena Fernandes, Sam Gaylard, Paul Lavery

Research outputs 2014 to 2021

The upper Spencer Gulf in South Australia hosts the world's largest single stream Pb-Zn smelter, which has caused environmental and health issues related to elevated metal concentrations in the surrounding environment. The area also has extensive seagrass meadows, occupying >4000 km². We reconstructed the fluxes of heavy metals over the last ~3000 years through a multi-parameter study of the soil archives formed by the seagrass Posidonia australis. Pb, Zn and Cd concentrations increased up to 9-fold following the onset of smelter operations in the 1880s, and the stable Pb isotopic signatures confirmed the smelter has been the main …

A Marine Heatwave Drives Massive Losses From The World’S Largest Seagrass Carbon Stocks, A. Arias-Ortiz, Oscar Serrano, Pere Masque´, Paul S. Lavery, Ute Mueller, G. A. Kendrick, Mohammad Rozaimi, Alba Esteban, J. W. Fourqurean, N. Marba, Miguel-Angel Mateo, K. Murray, M. J. Rule, C. M. Duarte

Research outputs 2014 to 2021

Seagrass ecosystems contain globally significant organic carbon (C) stocks. However, climate change and increasing frequency of extreme events threaten their preservation. Shark Bay, Western Australia, has the largest C stock reported for a seagrass ecosystem, containing up to 1.3% of the total C stored within the top metre of seagrass sediments worldwide. On the basis of field studies and satellite imagery, we estimate that 36% of Shark Bay’s seagrass meadows were damaged following a marine heatwave in 2010/2011. Assuming that 10 to 50% of the seagrass sediment C stock was exposed to oxic conditions after disturbance, between 2 and 9 …

Carbon Sequestration By Australian Tidal Marshes, Peter I. Macreadie, Q. R. Oliver, J. J. Kelleway, Oscar Serrano, P. E. Carnell, C. J. Ewers Lewis, T. B. Atwood, J. Sanderman, J. Baldock, R. M. Connolly, C. M. Duarte, Paul Lavery, A. Steven, C. E, Lovelock

Research outputs 2014 to 2021

Australia’s tidal marshes have suffered significant losses but their recently recognised importance in CO2 sequestration is creating opportunities for their protection and restoration. We compiled all available data on soil organic carbon (OC) storage in Australia’s tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha − 1 (range 14 – 963 Mg OC ha − 1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha − 1 yr − 1. Geomorphology was the most important predictor of OC stocks, with fluvial sites having twice the stock of OC …

Sediment Burial Stress Response, Bio-Indicators And Thresholds For A Tropical Multi-Species Seagrass Assemblage: Report Of Theme 5 - Project 5.5.2 Prepared For The Dredging Science Node, John Statton, Kathryn Mcmahon, Roisin Mccallum, Gary Kendrick, Paul Lavery

Research outputs 2014 to 2021

Deterioration in water clarity by resuspension of dredged sediments is presumed to be a major mechanism by which dredging can impact seagrasses. This report presents findings from a controlled light experiment that aimed to determine the effects of low light stress on the growth of three seagrass species found in the northwest of Western Australia.

Aims

• To determine the effects of sediment burial stress under dredge-simulated conditions on the growth and health of three seagrass species found in the northwest of Western Australia.
• Provide guidance and protocols for the application of the research outputs (e.g. seagrass burial stress:response relationships, sub-lethal …

Response And Recovery Of A Mixed Tropical Seagrass Assemblage To Variation In The Frequency And Magnitude Of Light Deprivation. Report Of Theme 5 - Project 5.5.3 Prepared For The Dredging Science Node, John Statton, Kathryn Mcmahon, Rosin Mccallum, Gary Kendrick, Paul Lavery

Research outputs 2014 to 2021

The capacity of seagrasses to cope with episodes of light deprivation from overlying turbid waters may not only depend on the absolute quantity of light they receive during that episode, but also on how the light deprivation varies through time. For example, turbidity and therefore light reduction may be relatively constant over the episode or it may fluctuate depending on the frequency of pulsed turbidity events.

This report presents findings from a controlled mesocosm experiment that aimed to determine the responses of seagrasses to, and recovery from, differences in the pattern of the delivery of light. The study focussed on …

Muddy Waters: Unintentional Consequences Of Blue Carbon Research Obscure Our Understanding Of Organic Carbon Dynamics In Seagrass Ecosystems, E. Fay Belshe, Miguel-Angel Mateo, Lucy Gillis, Martin Zimmer, Mirta Teichberg

Research outputs 2014 to 2021

The recent surge in research on organic carbon sequestration by seagrass ecosystems has begun to reveal the complexity of the carbon cycle within these ecosystems. In this prospective we discuss two areas of investigation that require further scrutiny: (1) why organic carbon is stabilized in seagrass sediments, and (2) how long organic carbon resides within these sediments. By delving into these topics, pointing out current pitfalls, and highlighting methodological advances, our motive is to focus future efforts and provide a frame work to manage the complexity found within the diverse seagrass bioregions. The high rate of seagrass degradation and loss, …

Genetic Variability Within Seagrass Of The North West Of Western Australia: Report Of Theme 5 - Project 5.2 Prepared For The Dredging Science Node, Kathryn Mcmahon, Udhi Hernawan, Kor-Jent Van Dijk, Michelle Waycott, Ed Biffin, Richard Evans, Paul Lavery

Research outputs 2014 to 2021

This study was the first of its kind to examine the patterns of genetic diversity in seagrasses in the Pilbara region of WA. Three species were assessed: Halophila ovalis (6 populations), Halodule uninervis (8 populations) andThalassia hemprichii (3 populations) at a range of spatial scales, within a meadow (centimetres−metres), among meadows at a local scale (2−60 km) and among meadows at a regional scale (up to 500 km). Due to the varied distribution of species all species across the same spatial scale and range of environments could not be sampled, so a nested approach was designed, with sites …

Natural Dynamics: Understanding Natural Dynamics Of Seagrasses Of The North West Of Western Australia. Report Of Theme 5 - Project 5.3 Prepared For The Dredging Science Node, Mat Vanderklift, Douglas Bearham, Mick Haywood, Hector Lozano-Montes, Roisin Mccallum, James Mclaughlin, Kathryn Mcmahon, Nick Mortimer, Paul Lavery

Research outputs 2014 to 2021

Relatively little is known of the spatial and temporal dynamics of seagrass meadows in the northwest of Western Australia, but such knowledge is needed when designing and evaluating studies that aim to detect potential dredging-related impacts on seagrass, and when making predictions about the likelihood of, and speed of recovery from such impacts. This study was undertaken to improve our understanding of the spatial and temporal patterns in seagrass composition, abundance and reproductive phenology in the Pilbara. We also characterised key environmental parameters, especially light, that influence seagrass survival and can be altered by dredging.

Aims

To improve our understanding …

Seagrasses Of The North West Of Western Australia: Biogeography And Considerations For Dredging-Related Research: Report Of Theme 5 - Project 5.1.2 Prepared For The Dredging Science Node, Kathryn Mcmahon, John Statton, Paul Lavery

Research outputs 2014 to 2021

This review was undertaken to identify which seagrass primary producers (species or different functional groups) that collectively cover the bio-geographic range of key primary producers in the northwest of Western Australia are most appropriate for the focus of subsequent research into thresholds and indicators of response to dredging-related pressures (i.e. Theme 5). An assessment framework was developed based on six criteria: biogeographic range; ecological relevance (life-history strategy, habitats, natural dynamics and ecological services); current knowledge on thresholds and bioindicators; likelihood that species are sensitive and resilient to dredging related stressors; extent of improvement in applied knowledge; and likelihood of being …

Current State Of Knowledge Regarding The Effects Of Dredging-Related ‘Pressure’ On Seagrasses: Report Of Theme 5 - Project 5.1.1 Prepared For The Dredging Science Node, Kathryn Mcmahon, Paul Lavery, John Statton, Roisin Mccallum, Udhi Hernawan

Research outputs 2014 to 2021

This review summarises our understanding, from a northwest of Western Australia and global perspective, the pressures seagrasses are exposed to from dredging, their tolerance thresholds and responses to dredging related stressors, and the bioindicators of dredging related stressors. From this information, we also identified gaps in our knowledge and areas where environmental management and monitoring approaches could be improved.

Aims

To determine the levels of stress (light reduction/sediment deposition) that occur under dredging conditions and evaluate the likely effect of these levels of pressure based on the existing seagrass literature, considering the range of variability and environmental quality conditions associated …

Effects Of Dredging-Related Pressures On Critical Ecological Processes For Organisms Other Than Fish Or Coral. Report Of Theme 9 - Project 9.1 Prepared For The Dredging Science Node, Jessie Short, Matthew Fraser, Dianne Mclean, Gary Kendrick, Maria Byrne, Julian Caley, Doug Clarke, Andy Davis, Paul Ertemeijer, Stuart Field, Sam Gustin-Craig, John Huisman, John Keesing, Mick Keough, Paul Lavery, Ray Mansini, Kathryn Mcmahon, Kerrie Mergersen, Michael Rasheed, John Statton, Jim Stoddart, Paul Wu

Research outputs 2014 to 2021

This study reviewed environmental windows for organisms other than corals and fish such as sessile invertebrates, macroalgae and seagrasses. Environmental windows are periods of critical importance to the life history of a marine species, like reproduction and recruitment.

Aims

• To review the scientific literature on the timing and spatial extent of critical ecological processes relevant to tropical WA for marine primary producers and invertebrates (i.e. organisms other than coral and finfish) and the state of knowledge regarding potential effects of dredging on these key ecological processes. The review also had a particular focus on ecological processes in marine primary producers …

Residence Time In Coastal Canopies, Maryam Abdolahpour

Theses: Doctorates and Masters

Aquatic canopies provide important ecosystem services such as improved water quality, oxygen flux, sediment stabilisation and trapping and recycling of nutrients. The ecological health of coastal canopies and the significant ecosystem services they provide depends largely on the continuous exchange of dissolved and particulate materials across the canopy boundaries. In coastal environments, where flow is typically wavedominated, vertical mixing is believed to be the dominant process controlling residence time and, therefore, exchange. However, experiments have shown that wave-driven flows over rough boundaries, such as canopies, generate strong onshore mean currents (75% of the orbital velocity far above the canopy) near …