Marine Biology Commons^™

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 …

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 …

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 …

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, …

A Marine Heat Wave Drives Massive Losses From The World’S Largest Seagrass Carbon Stocks, Ariane Arias-Ortiz, Oscar Serrano, Pere Masqué, Paul Lavery, Ute A. Mueller, Gary A, Kendrick, Mohammad Rozaimi, Alba Esteban, James W, Fourqurean, Núrià N. Marbà, Miquel-Angel Mateo, Kathy Murray, Michael Rule, Carlos M. Duarte

Research Datasets

The database compiles published data (in Arias-Ortiz et al., 2018) on biogeochemical characteristics (density, organic carbon, stable carbon isotopes and sediment grain size) of soils underneath seagrass meadows in Shark Bay, Western Australia. Pb-210 concentrations of the first 20 cm are included along with C-14 raw ages. The dataset compiles data for a total of 49 cores, 25 - 300 cm-long (11 cores with Pb-210 and C-14 data).

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 …

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 …

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 …

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 …

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 …

Investigating The Effects Of Changes In Light Quality On Different Life History Stages Of Seagrasses, Simone Strydom

Theses: Doctorates and Masters

Seagrass meadows provide crucial ecosystem services to the coastal zone but globally are threatened. Seagrass loss to date has mainly been attributed to anthropogenic activities that reduce light quantity, such as dredging, declining water quality from urban and agricultural run-off and eutrophication. However, light quality (wavelengths of light) is also altered by these anthropogenic stressors as well as natural events. This study consisted of three main components: (1) characterising light quality to which seagrasses are exposed across a local natural estuarine-ocean gradient and with a human impact pressure; (2) the influence of monochromatic light quality (blue λ=451 nm; green λ=522 …

Should We Sync? Seascape-Level Genetic And Ecological Factors Determine Seagrass Flowering Patterns, Marlene Jahnke, Jordi F. Pagès, Teresa Alcoverro, Paul S. Lavery, Kathryn M. Mcmahon, Gabriele Procaccini

Research Datasets

Spatial and temporal heterogeneity in flowering occur in many plant species with abiotic pollination and may confer fitness advantages through mechanisms such as predator satiation or pollination efficiency. Environmental factors such as light quality or quantity and temperature play an important role in inducing synchronisation on wide geographic scales. On a smaller geographic scale, external factors such as resource availability and herbivory are theorised to trigger flowering, while genetic factors may also play an important role. In this study, we assessed the importance of ecological and genetic factors in shaping seascape-level spatial heterogeneity in flowering of the seagrass Posidonia oceanica. …

Accelerating Tropicalization And The Transformation Of Temperate Seagrass Meadows, Glenn A. Hyndes, Kenneth L. Heck, Jnr, Adriana Verges, Euan S. Harvey, Gary A. Kendrick, Paul Lavery, Kathryn Mcmahon, Robert J. Orth, Alan Pearce, Mathew Vanderklift, Thomas Wernberg, Scott Whiting, Shaun Wilson

Research outputs 2014 to 2021

Climate-driven changes are altering production and functioning of biotic assemblages in terrestrial and aquatic environments. In temperate coastal waters, rising sea temperatures, warm water anomalies and poleward shifts in the distribution of tropical herbivores have had a detrimental effect on algal forests. We develop generalized scenarios of this form of tropicalization and its potential effects on the structure and functioning of globally significant and threatened seagrass ecosystems, through poleward shifts in tropical seagrasses and herbivores. Initially, we expect tropical herbivorous fishes to establish in temperate seagrass meadows, followed later by megafauna. Tropical seagrasses are likely to establish later, delayed by …

Impact Of Mooring Activities On Carbon Stocks In Seagrass Meadows, Oscar Serrano, R. Ruhon, Paul S. Lavery, Gary A. Kendrick, S. Hickey, Pere Masque, Ariane Arias-Ortiz, Andy D.L. Steven, Carlos M. Duarte

Research outputs 2014 to 2021

Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (C_org) stocks, which may contribute to increasing atmospheric CO₂. This study presents the first estimates of loss of C_org stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The C_org stores have been compromised by the mooring deployment from 1930s onwards, which involved …

Influence Of Increased Sediment Exposure On Suspension-Feeder Assemblages In A Temperate Seagrass Meadow, Pierre Bouvais

Theses: Doctorates and Masters

The impact of increased sediment exposure on coastal marine ecosystems is one of the most important contemporary environmental issues. Sediment exposure is defined as the concentrations of sediment particles suspended in the water column and the amount of sediment depositing on the seabed. In addition to natural events, such as land erosion, rainfall, and tidal currents, anthropogenic activities such as land use, road building, logging, mining, port maintenance and dredging, contribute to the discharge of a great amount of sediment in the water column. As sessile suspension-feeder assemblages play a critical role in marine ecosystems through their active transfers of …

Gene Flow And Genetic Structure Of The Seagrass Thalassia Hemprichii In The Indo-Australian Archipelago, Udhi Eko Hernawan

Theses: Doctorates and Masters

How genetic variation is distributed across space (genetic structure) and what factors influence the spatial genetic structuring is one of the primary questions in population genetics. The interaction between species biology (e.g. life-history traits) and physical processes operating in the seascape over time, including palaeo-historical events (e.g. sea level fluctuations) and contemporary processes (e.g. ocean currents), have been predicted to influence the extent of gene flow and the spatial genetic structuring in marine organisms. However, the relative contribution of each factor in governing the genetic pattern remains unclear. This study examined the pattern of genetic structure and the factors influencing …

Glomalin Accumulated In Seagrass Sediments Reveals Past Alterations In Soil Quality Due To Land-Use Change, Lourdes López-Merino, Oscar Serrano, María Fernanda Adame, Miguel-Ángel Mateo, Antonio Martínez Cortizas

Research outputs 2014 to 2021

Arbuscular mycorrhizal fungi (AMF), symbionts with most terrestrial plants, produce glomalin-related soil protein (GRSP), which plays a major role in soil structure and quality. Both fungi hyphae and protein production in soils are affected by perturbations related to land-use changes, implying that GRSP is a sensitive indicator of soil quality. Unfortunately, GRSP degrades within years to decades in oxic environments, preventing its use as palaeoecological proxy. However, GRSP is transported to marine, near-shore anoxic sediments, where it accumulates and remains non-degraded, enabling the assessment of its potential as a palaeoecological proxy for soil ecosystem's health. Exploiting this fact, we have …

Carbon Storage And Preservation In Seagrass Meadows, Mohammad Rozaimi Jamaludin

Theses: Doctorates and Masters

Seagrass meadows are important ‘Blue Carbon’ sinks but many questions remain unaddressed in regards to the organic carbon (OC) sequestration capacity and processes leading to retention and persistence of OC in seagrass sediments. The research summarised in this dissertation examined 37 sediment cores from twelve Australian seagrass meadows (Posidonia australis and Halophila ovalis) in order to improve our understanding of OC storage and preservation in seagrass sediments. The research: quantified the OC storage in seagrass meadows and the reduction in stores after ecosystem degradation; the rates of OC accumulation; the roles of species composition and the depositional nature …

Mechanisms And Ecological Role Of Carbon Transfer Within Coastal Seascapes, Glenn A. Hyndes, Ivan Nagelkerken, Rebecca Mcleod, Rod Connolly, Paul S. Lavery, Mathew A. Vanderklift

Research outputs 2013

Worldwide, coastal systems provide some of the most productive habitats, which potentially influence a range of marine and terrestrial ecosystems through the transfer of nutrients and energy. Several reviews have examined aspects of connectivity within coastal seascapes, but the scope of those reviews has been limited to single systems or single vectors. We use the transfer of carbon to examine the processes of connectivity through multiple vectors in multiple ecosystems using four coastal seascapes as case studies. We discuss and compare the main vectors of carbon connecting different ecosystems, and then the natural and human-induced factors that influence the magnitude …

Influence Of Hydrological And Environmental Conditions On Mangrove Vegetation At Coastal And Inland Semi-Arid Areas Of The Gascoyne Region, Natasha Robin Dunham

Theses: Doctorates and Masters

Mangrove stands are uncommon within semi-arid climates and rare within inland systems. It is uncertain whether the same environmental variables influence mangroves growing in a semi-arid climate as the trees growing in tropical and sub-tropical areas. Field studies conducted on the ecophysiological responses of the mangrove species Avicennia marina are few; however hydrological regimes are considered the key factor influencing mangrove stand zonation, structure and individual tree growth. The Gascoyne region of Western Australia provides a unique opportunity to investigate whether mangroves growing within an inland semi-arid environment display similar growth patterns and ecophysiological responses to their coastal counterparts.

This …

The Biology And Ecology Of Epinephilidae Speciea And Their Implications To Fisheries Management, Jason R. How

Theses: Doctorates and Masters

This thesis examines the biological and ecological aspects of members of the globally exploited Epinephilidae with reference to fisheries management and in particular the use of closures. The leopard coralgrouper Plectropomus leopardus is a common reef fish throughout the Indo-Pacific region and a major target of both commercial and recreational fisheries. There has been limited research on this species in the eastern Indian Ocean, where there are only two populations. An examination of the species found a number of significant biological differences to their eastern Australian con-specifics. Most noticeable was the strong size-related cue over their protogynous sex change. The …

Release Of Dissolved Organic Carbon From Seagrass Wrack And Its Implications For Trophic Connectivity, Paul S. Lavery, Kathryn M. Mcmahon, Julia Weyers, Mary C. Boyce, Carolyn Elizabeth Oldham

Research outputs 2013

The export of old leaves and stems (wrack) from seagrass meadows provides a mechanism for trophic connectivity among coastal ecosystems. As little of this wrack is consumed by mesograzers, leached dissolved organic carbon (DOC) may determine the importance of wrack as a trophic subsidy. However, few studies have examined the effect of seagrass type or age on the release of DOC or its bioavailability. We examined the amount and composition of DOC released from different wrack: Posidonia sinuosa, Amphibolis antarctica and the alga Laurencia sp. We then examined the effect of age on DOC leaching from P. sinuosa wrack. The …

Meta-Analysis Reveals Complex Marine Biological Responses To The Interactive Effects Of Ocean Acidification And Warming, Ben P. Harvey, Dylan Gwynn-Jones, Philippa J. Moore

Research outputs 2013

Ocean acidification and warming are considered two of the greatest threats to marine biodiversity, yet the combined effect of these stressors on marine organisms remains largely unclear. Using a meta-analytical approach, we assessed the biological responses of marine organisms to the effects of ocean acidification and warming in isolation and combination. As expected biological responses varied across taxonomic groups, life-history stages, and trophic levels, but importantly, combining stressors generally exhibited a stronger biological (either positive or negative) effect. Using a subset of orthogonal studies, we show that four of five of the biological responses measured (calcification, photosynthesis, reproduction, and survival, …

Variability In The Carbon Storage Of Seagrass Habitats And Its Implications For Global Estimates Of Blue Carbon Ecosystem Service, Paul Lavery, Miguel-Angel Mateo, Oscar Serrano, Mohammad Rozaimi

Research outputs 2013

The recent focus on carbon trading has intensified interest in ‘Blue Carbon’–carbon sequestered by coastal vegetated ecosystems, particularly seagrasses. Most information on seagrass carbon storage is derived from studies of a single species, Posidonia oceanica, from the Mediterranean Sea. We surveyed 17 Australian seagrass habitats to assess the variability in their sedimentary organic carbon (Corg) stocks. The habitats encompassed 10 species, in mono-specific or mixed meadows, depositional to exposed habitats and temperate to tropical habitats. There was an 18-fold difference in the Corg stock (1.09– 20.14 mg Corg cm23 for a temperate Posidonia sinuosa and a temperate, estuarine P. australis …

Sources And Supply Of Kelp Detritus : Quantifying Mechanisms Of Production, Thibaut De Bettignies

Theses: Doctorates and Masters

In temperate waters, rocky reefs dominated by extremely productive kelp beds export considerable primary production. Despite the extensive body of work on kelp detritus as a trophic subsidy, many questions remain about the production of this detritus. The aim of this thesis was to determine the rate and mechanisms of kelp detritus production, for Ecklonia radiata, the dominant kelp species in temperate Australia. Most of the work was conducted in Marmion Lagoon located 20 km North of Perth, south-western Western Australia, a region strongly influenced by oceanic swell and winter storms. The study comprised of four major components: the impact …

Herbivory By Parma Mccullochi (Pomacentridae) : Its Role As An Ecosystem Engineer In Temperate Algal-Dominated Reefs, Frederico Vitelli

Theses: Doctorates and Masters

Pomacentridae is one of the most representative families of herbivorous fishes inhabiting both tropical and temperate reefs, yet the vast majority of studies examining feeding within this family have been undertaken in tropical rather than temperate regions. Despite the high abundances of the pomacentrid Parma mccullochi in temperate waters of Western Australia, and their likely importance in removing algae from reefs in the region, there is a lack of information on their diet and their impact on the reef algal community. This study aims to determine the role of Parma mccullochi as an ecosystem engineer on temperate algal-dominated reefs in …

Drift Algae, An Invasive Snail And Elevated Temperature Reduce Ecological Performance Of A Warm-Temperate Seagrass, Through Additive Effects, H Hoffle, Thomas Wernberg, Mads Thomsen, M Holmer

Research outputs 2012

Seagrasses are under pressure from multiple concurrent threats, including rising temperatures, invasive species and nutrient-driven algal accumulations. We quantified the abundance of drift algae and the invasive snail Batillaria australis in 3 Halophila ovalis seagrass beds in the Swan River Estuary (Perth, Western Australia), and tested in an aquarium experiment for interactive effects of temperature (21 vs. 27°C), cover of drift algae Chaetomorpha linum (0 vs. 1.4 kg fresh wt m -2) and presence (0 vs. 120 snails m -2) of B. australis on the ecological performance of H. ovalis. The survey showed that drift algae varied considerably between sites …

Wounded Kelps: Patterns And Susceptibility To Breakage, Thibaut De Bettignies, Mads Thomsen, Thomas Wernberg

Research outputs 2012

Kelps are highly productive seaweeds predominantly found in wave-exposed environments. Physical and biological processes such as sand abrasion, whiplash and grazing can wound kelp tissue, potentially weakening its ability to withstand wave forces. Despite the ecological importance of kelp tissue loss, few studies have quantified wounding patterns in kelps or how wounding might affect the biomechanical properties of kelps. We quantified the prevalence of wounds on 360 Ecklonia radiata kelps collected across 3 different reef lines (levels of wave exposure) in April (autumn), June (early winter), August (winter) and October (early spring) (i.e. before, during and after peak wave activity). …

Role Of Food Availability In The Bathymetric Distribution Of The Starfish Marthasterias Glacialis (Lamk.)On Reefs Of Northern Portugal [Efecto De La Disponibilidad Alimenticia Sobre La Distribución Batimétrica De La Estrella De Mar Marthasterias Glacialis (Lamk.) En Arrecifes Del Norte De Portugal], Fernando Tuya, Pedro Duarte

Research outputs 2012

We examined whether the abundance and size of the starfish Marthasterias glacialis (Lamk.) exhibit a depth-dependent partitioning on subtidal reefs. We tested the hypothesis that differences in food availability can result in habitat partitioning along a depth gradient. The abundance and size of M. glacialis was registered at 4 depth strata: 0-4 m, 4-8 m, 8-12 m, and >12 m; we also recorded the number of food items that they were preying on. The abundance and size of M. glacialis decreased with depth. Mussels (Mytilus galloprivincialis) were the most preyed food item across all depth strata, followed by …