Life Sciences Commons^™

Environmental Gradients And Physical Barriers Drive The Basin-Wide Spatial Structuring Of Mediterranean Sea And Adjacent Eastern Atlantic Ocean Prokaryotic Communities, Marta Sebastián, Eva Ortega-Retuerta, Laura Gómez-Consarnau, Marina Zamanillo, Marta Álvarez, Javier Arístegui, Josep M. Gasol

Research outputs 2014 to 2021

The Mediterranean Sea is a miniature ocean divided by the Sicily Strait into two basins with a marked west to east trophic gradient and separated of the nearby eastern Atlantic Ocean by the Strait of Gibraltar. Here, we test the hypothesis that these physical and environmental barriers favor the development of specific prokaryotic assemblages, leading to changes in community structure both in the vertical and horizontal spatial scales. By analyzing taxonomic and phylogenetic diversity using amplicon sequence variants (ASVs) of the 16S rRNA gene, we show that there is indeed marked vertical segregation of prokaryotic groups, similar to that found …

What Lies Beneath: Predicting Seagrass Below-Ground Biomass From Above-Ground Biomass, Environmental Conditions And Seagrass Community Composition, C. J. Collier, L. M. Langlois, Kathryn M. Mcmahon, J. Udy, M. Rasheed, E. Lawrence, A. B. Carter, M. W. Fraser, L. J. Mckenzie

Research outputs 2014 to 2021

© 2020 Seagrass condition, resilience and ecosystem services are affected by the below-ground tissues (BGr) but these are rarely monitored. In this study we compiled historical data across northern Australia to investigate biomass allocation strategies in 13 tropical seagrass species. There was sufficient data to undertake statistical analysis for five species: Cymodocea serrulata, Halophila ovalis, Halodule uninervis, Thalassia hemprichii, and Zostera muelleri. The response of below-ground biomass (BGr) to above-ground biomass (AGr) and other environmental and seagrass community composition predictor variables were assessed using Generalized Linear Models. Environmental data included: region, season, sediment type, water depth, proximity to land-based sources …

Accounting For The Influence Of Temperature And Location When Predicting Seagrass (Halophila Ovalis) Photosynthetic Performance, Nicole E. Said, Kathryn Mcmahon, Paul Lavery

Research outputs 2014 to 2021

We show that the effect of temperature on photosynthesis of a widely distributed and ecological important seagrass species was not consistent among locations, with some evidence of acclimation to the local temperature range. This has important implications for modelling seagrass productivity and the impacts of light reduction on seagrass ecosystems. Reduced light availability is one of the main pressures negatively impacting on seagrass meadows worldwide. Our knowledge of seagrass photosynthetic characteristics is critical to predicting and managing impacts of light reducing activities but suffers from two critical information gaps: first, data is overwhelmingly derived from studies of leaf tissue and …

Effect Of Seawater Ageing On Fracture Toughness Of Stitched Glass Fiber/Epoxy Laminates For Marine Applications, Atizaz Hassan, Rafiullah Khan, Numan Khan, Muhammad Aamir, Danil Y. Pimenov, Khaled Giasin

Research outputs 2014 to 2021

Composite materials are used in various industries such as marine, aircraft, automotive, etc. In marine applications, composites are exposed to seawater, which can affect their mechanical properties due to moisture absorption. This work focuses on the durability of composite materials under the short-term effect of seawater ageing. The specimens were prepared from glass fiber/epoxy using a hand lap-up method and stitched in the z-direction with Kevlar fiber. The specimens were submerged in seawater for 24 and 35 days. A significant decrease in maximum load was found as specimen immersion time in seawater increased. The seawater ageing also affected fracture toughness …

Deciphering The Unique Structure And Acylation Pattern Of Posidonia Oceanica Lignin, Jorge Rencoret, Gisela Marques, Oscar Serrano, Joeri Kaal, Angel T. Martínez, José C. Del Río, Ana Gutiérrez

Research outputs 2014 to 2021

Copyright © 2020 American Chemical Society. Lignins from different parts of the seagrass Posidonia oceanica-namely sheaths, rhizome, and roots-as well as from fibrous balls from P. oceanica detritus were isolated and thoroughly characterized by pyrolysis coupled with gas chromatography/mass spectrometry, derivatization followed by reductive cleavage, two-dimensional nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The lignins of P. oceanica were enriched in guaiacyl (G) over syringyl (S) units, with S/G ratios ranging from 0.1 (fibrous balls) to 0.5 (rhizome). β-O-4′ ethers and phenylcoumarans were the most abundant lignin substructures, followed by resinols, and minor amounts of dibenzodioxocins and spirodienones. Moreover, …

Contribution Of Seagrass Blue Carbon Toward Carbon Neutral Policies In A Touristic And Environmentally-Friendly Island, Camila Bedulli, Paul S. Lavery, Matt Harvey, Carlos M. Duarte, Oscar Serrano

Research outputs 2014 to 2021

Estimates of organic carbon (C_org) storage by seagrass meadows which consider inter-habitat variability are essential to understand their potential to sequester carbon dioxide (CO₂) and derive robust global and regional estimates of blue carbon storage. In this study, we provide baseline estimates of seagrass extent, and soil C_org stocks and accumulation rates from different seagrass habitats at Rottnest Island (in Amphibolis spp., Posidonia spp., Halophila ovalis, and mixed Posidonia/Amphibolis spp. meadows). The C_org stocks in 0.5 m thick seagrass soil deposits, derived from 24 cores, were 5.1 ± 0.7 kg C_org m^{–2 …}

Coral Microbiome Database: Integration Of Sequences Reveals High Diversity And Relatedness Of Coral-Associated Microbes, Megan J. Huggett, Amy Apprill

Research outputs 2014 to 2021

Coral-associated microorganisms are thought to play a fundamental role in the health and ecology of corals, but understanding of specific coral-microbial interactions are lacking. In order to create a framework to examine coral-microbial specificity, we integrated and phylogenetically compared 21,100 SSU rRNA gene Sanger-produced sequences from bacteria and archaea associated with corals from previous studies, and accompanying host, location and publication metadata, to produce the Coral Microbiome Database. From this database, we identified 39 described and candidate phyla of Bacteria and two Archaea phyla associated with corals, demonstrating that corals are one of the most phylogenetically diverse animal microbiomes. Secondly, …

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 …

Role Of Carbonate Burial In Blue Carbon Budgets, V. Saderne, N.R. Geraldi, P.I. Macreadie, D.T. Maher, J.J. Middelburg, O. Serrano, H. Almahasheer, A. Arias-Ortiz, M. Cusack, B.D. Eyre, J.W. Fourqurean, H. Kennedy, D. Krause-Jensen, T. Kuwae, P.S. Lavery, C.E. Lovelock, N. Marba, P. Masqué, M.A. Mateo, I. Mazarrasa, K.J. Mcglathery, M.P.J. Oreska, C.J. Sanders, I.R. Santos

Research outputs 2014 to 2021

Calcium carbonates (CaCO 3 ) often accumulate in mangrove and seagrass sediments. As CaCO 3 production emits CO 2 , there is concern that this may partially offset the role of Blue Carbon ecosystems as CO 2 sinks through the burial of organic carbon (C org ). A global collection of data on inorganic carbon burial rates (C inorg , 12% of CaCO 3 mass) revealed global rates of 0.8 TgC inorg yr −1 and 15–62 TgC inorg yr −1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO 3 burial may correspond to an offset of 30% of the …

Seagrass Removal Leads To Rapid Changes In Fauna And Loss Of Carbon, Michael N. Githaiga, Anna M. Frouws, James G. Kairo, Mark Huxham

Research outputs 2014 to 2021

Seagrass habitats are important natural carbon sinks, with an average of ~14 kg C m⁻² buried in their sediments. The fate of this carbon following seagrass removal or damage has major environmental implications but is poorly understood. Using a removal experiment lasting 18 months at Gazi Bay, Kenya, we investigated the impacts of seagrass loss on sediment topography, hydrodynamics, faunal community structure and carbon dynamics. Sediment pins were used to monitor surface elevation. The effects of seagrass removal on water velocity was investigated using Plaster of Paris dissolution. Sediment carbon concentration was measured at the surface and down to …

Global Trends In Marine Plankton Diversity Across Kingdoms Of Life, Federico M. Ibarbalz, Nicolas Henry, Manoela C. Brandão, Severine Martini, Greta Busseni, Hannah Byrne, Luis Pedro Coelho, Hisashi Endo, Josep Gasol, Ann C. Gregory, FréDéRic Mahe ́, Janaina Rigonato, Marta Royo-Llonch, Guillem Salazar, Isabel Sanz-SáEz, Eleonora Scalco, Dodji Soviadan, Ahmed A. Zayed, Adriana Zingone, Karine Labadie, Joannie Ferland, Claudie Marec, Stefanie Kandels, Marc Picheral, Celine Dimier, Julie Poulain, Sergey Pisarev, Margaux Carmichael, Stephane Pesant, Marcel Babin, Emmanuel Boss, Daniele Iudicone, Olivier Jaillon, Silvia G. Acinas, Hiroyuki Ogata, Eric Pelletier, Lars Stemmann, Matthew B. Sullivan, Shinichi Sunagawa, Laurent Bopp, Colomban De Vargas, Lee Karp-Boss, Patrick Wincker, Fabien Lombard, Chris Bowler, Lucie Zinger

Research outputs 2014 to 2021

The ocean is home to myriad small planktonic organisms that underpin the functioning of marine ecosystems. However, their spatial patterns of diversity and the underlying drivers remain poorly known, precluding projections of their responses to global changes. Here we investigate the latitudinal gradients and global predictors of plankton diversity across archaea, bacteria, eukaryotes, and major virus clades using both molecular and imaging data from Tara Oceans. We show a decline of diversity for most planktonic groups toward the poles, mainly driven by decreasing ocean temperatures. Projections into the future suggest that severe warming of the surface ocean by the end …

Seagrass Sedimentary Deposits As Security Vaults And Time Capsules Of The Human Past, Dorte Krause-Jensen, Oscar Serrano, Eugenia T. Apostolaki, David J. Gregory, Carlos M. Duarte

Research outputs 2014 to 2021

Seagrass meadows form valuable ecosystems, but are considered to have low cultural value due to limited research efforts in this field. We provide evidence that seagrass deposits play a hitherto unrealized central role in preserving valuable submerged archaeological and historical heritage across the world, while also providing an historical archive of human cultural development over time. We highlight three case studies showing the significance of seagrass in protecting underwater cultural heritage in Denmark, the Mediterranean and Australia. Moreover, we present an overview of additional evidence compiled from the literature. We emphasize that this important role of seagrasses is linked to …

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 …

Carbon Stocks And Accumulation Rates In Red Sea Seagrass Meadows, Oscar Serrano, Hanan Almahasheer, Carlos M Duarte, Xabier Irigoien

Research outputs 2014 to 2021

Seagrasses play an important role in climate change mitigation and adaptation, acting as natural CO₂ sinks and buffering the impacts of rising sea level. However, global estimates of organic carbon (C_org) stocks, accumulation rates and seafloor elevation rates in seagrasses are limited to a few regions, thus potentially biasing global estimates. Here we assessed the extent of soil C_org stocks and accumulation rates in seagrass meadows (Thalassia hemprichii, Enhalus acoroides, Halophila stipulacea, Thalassodendrum ciliatum and Halodule uninervis) from Saudi Arabia. We estimated that seagrasses store 3.4 ± 0.3 kg C_{org …}

Cumulative Stress Restricts Niche Filling Potential Of Habitat-Forming Kelps In A Future Climate, Nathan G. King, David C. Wilcockson, Richard Webster, Dan A. Smale, Laura S. Hoelters, Pippa J. Moore

Research outputs 2014 to 2021

Climate change is driving range contractions and local population extinctions across the globe. When this affects ecosystem engineers the vacant niches left behind are likely to alter the wider ecosystem unless a similar species can fulfil them.
Here, we explore the stress physiology of two coexisting kelps undergoing opposing range shifts in the Northeast Atlantic and discuss what differences in stress physiology may mean for future niche filling.
We used chlorophyll florescence (F_v/F_m) and differentiation of the heat shock response (HSR) to determine the capacity of the expanding kelp, Laminaria ochroleuca, to move …

Spatial Variability In The Diversity And Structure Of Faunal Assemblages Associated With Kelp Holdfasts (Laminaria Hyperborea) In The Northeast Atlantic, Harry Teagle, Pippa J. Moore, Helen Jenkins, Dan A. Smale

Research outputs 2014 to 2021

Kelp species are ecologically-important habitat-formers in coastal marine ecosystems, where they alter environmental conditions and promote local biodiversity by providing complex biogenic habitat for an array of associated organisms. While it is widely accepted that kelps harbour significant biodiversity, our current understanding of spatiotemporal variability in kelp-associated assemblages and the key environmental drivers of variability patterns remains limited. Here we examined the influence of ocean temperature and wave exposure on the structure of faunal assemblages associated with the holdfasts of Laminaria hyperborea, the dominant habitat-forming kelp in the northeast Atlantic. We sampled holdfasts from 12 kelp-dominated open-coast sites nested …

Comment On 'Geoengineering With Seagrasses: Is Credit Due Where Credit Is Given?', Peter I. Macreadie, Carolyn J. Ewers-Lewis, Ashley A. Whitt, Quinn Ollivier, Stacey M. Trevathan-Tackett, Paul Carnell, Oscar Serrano

Research outputs 2014 to 2021

Over the past decade scientists around the world have sought to estimate the capacity of seagrass meadows to sequester carbon, and thereby understand their role in climate change mitigation. The number of studies reporting on seagrass carbon accumulation rates is still limited, but growing scientific evidence supports the hypothesis that seagrasses have been efficiently locking away CO2 for decades to millennia (e.g. Macreadie et al 2014, Mateo et al 1997, Serrano et al 2012). Johannessen and Macdonald (2016), however, challenge the role of seagrasses as carbon traps, claiming that gains in carbon storage by seagrasses …

Distributions Of Total And Size-Fractionated Particulate 210po And 210pb Activities Along The North Atlantic Geotraces Ga01 Transect: Geovide Cruise, Yi Tang, Maxi Castrillejo, Montserrat Roca-Marti, Pere Masque´, Nolwenn Lemaitre, Gillian Stewart

Research outputs 2014 to 2021

Vertical distributions of total and particulate polonium-210 (²¹⁰Po) and lead-210 (²¹⁰Pb) activities in the water column were measured at 11 stations in the North Atlantic during the GEOTRACES GA01 transect: GEOVIDE cruise in May–June 2014. Total ²¹⁰Po activity was on average 24% lower than ²¹⁰Pb activity in the upper 100m, and it was closer to unity in the mesopelagic (100–1000m). The partitioning coefficients (K_d) along the transect suggest the preferential association of ²¹⁰Po relative to ²¹⁰Pb onto particles. The prominent role of small particles in sorption was confirmed by …

Factors Controlling The Community Structure Of Picoplankton In Contrasting Marine Environments, Jose Luis Otero-Ferrer, Pedro Cermeno, Antonio Bode, Bieito Fernandez-Castro, Josep M. Gasol, Xose Anxelu G. Moran, Emilio Maranon, Victor Moreira-Coello, Marta M. Varela, Marina Villamana, Beatriz Mourino-Carballido

Research outputs 2014 to 2021

The effect of inorganic nutrients on planktonic assemblages has traditionally relied on concentrations rather than estimates of nutrient supply. We combined a novel dataset of hydrographic properties, turbulent mixing, nutrient concentration, and picoplankton community composition with the aims of (i) quantifying the role of temperature, light, and nitrate fluxes as factors controlling the distribution of autotrophic and heterotrophic picoplankton subgroups, as determined by flow cytometry, and (ii) describing the ecological niches of the various components of the picoplankton community. Data were collected at 97 stations in the Atlantic Ocean, including tropical and subtropical open-ocean waters, the northwestern Mediterranean Sea, and …

Short-Term Responses Of Posidonia Australis To Changes In Light Quality, Simone Strydom, Kathryn M. Mcmahon, Gary A. Kendrick, John Stratton, Paul S. Lavery

Research outputs 2014 to 2021

Seagrass meadows are highly productive ecosystems that provide ecosystem services to the coastal zone but are declining globally, particularly due to anthropogenic activities that reduce the quantity of light reaching seagrasses, such as dredging, river discharge and eutrophication. Light quality (the spectral composition of the light) is also altered by these anthropogenic stressors as the differential attenuation of wavelengths of light is caused by materials within the water column. This study addressed the effect of altered light quality on different life-history stages of the seagrass Posidonia australis, a persistent, habitat-forming species in Australia. Aquarium-based experiments were conducted to determine …

Sequestration Of Macroalgal Carbon: The Elephant In The Blue Carbon Room, Dorte Krause-Jensen, Paul Lavery, Oscar Serrano, Nu´Ria Marba, Pere Masque´, Carlos M. Duarte

Research outputs 2014 to 2021

Macroalgae form the most extensive and productive benthic marine vegetated habitats globally but their inclusion in Blue Carbon (BC) strategies remains controversial. We review the arguments offered to reject or include macroalgae in the BC framework, and identify the challenges that have precluded macroalgae from being incorporated so far. Evidence that macroalgae support significant carbon burial is compelling. The carbon they supply to sediment stocks in angiosperm BC habitats is already included in current assessments, so that macroalgae are de facto recognized as important donors of BC. The key challenges are (i) documenting macroalgal carbon sequestered beyond BC habitat, (ii) …

Radically Different Lignin Composition In Posidonia Species May Link To Differences In Organic Carbon Sequestration Capacity, Joeri Kaal, Oscar Serrano, José C.Del Río, Jorge Rencoret

Research outputs 2014 to 2021

There is considerable variability in the ability of seagrass ecosystems to sequester organic carbon (C_org) in their sediments, which act as natural carbon sinks contributing to climate change mitigation. In this work, we studied the chemistry of two Posidonia seagrass species aiming to elucidate whether differences in chemical composition might explain differences in their C_org sequestration capacity. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and Thermally assisted Hydrolysis and Methylation (THM) GC-MS data showed a remarkable difference in phenolic compound patterns between P. oceanica and P. australis bulk plants and individual organs (leaves, sheaths, roots and rhizomes). The lignin of …

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 …

Millennial-Scale Trends And Controls In Posidonia Oceanica (L. Delile) Ecosystem Productivity, Carman Leiva-Dueñas, Lourdes López-Merino, Oscar Serrano, Antonio Martínez Cortizas, Miguel-Angel Mateo

Research outputs 2014 to 2021

Posidonia oceanica is a marine phanerogam that buries a significant part of its belowground production forming an organic bioconstruction known as mat. Despite Posidonia seagrass mats have proven to be reliable archives of long-term environmental change, palaeoecological studies using seagrass archives are still scarce. Here we reconstruct four millennia of environmental dynamics in the NE coast of Spain by analysing the carbon and nitrogen stable isotopic composition of P. oceanica sheaths, the proportion of different seagrass organs throughout the seagrass mat and other sedimentological proxies. The palaeoenvironmental reconstruction informs on long-term ecosystem productivity and nutrient loading, which have been linked …

Remobilization Of Heavy Metals By Mangrove Leaves, Hanan Almahasheer, Oscar Serrano, Carlos M. Duarte, Xabier Irigoien

Research outputs 2014 to 2021

Several studies have been carried out on heavy metal pollution in mangrove ecosystems. However, the role of mangroves in heavy metal remobilization is still relatively unknown. On one side, mangrove woody organs and soils sequester heavy metals for long time periods, but on the other hand, senescence of mangrove leaves may return these metals collected by roots to the upper layers of the soil. Here, we analyzed the concentration of chemical elements (Al, As, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, V, and Zn) as a function of age in mangrove leaves to understand heavy metals retention by …

Timing Anthropogenic Stressors To Mitigate Their Impact On Marine Ecosystem Resilience, Paul Pao-Yen Wu, Kerrie Mengersen, Kathryn Mcmahon, Gary A. Kendrick, Kathryn Chartrand, Paul H. York, Michael A. Rasheed, M. Julian Caley

Research outputs 2014 to 2021

Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging campaigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although …

Low Carbon Sink Capacity Of Red Sea Mangroves, Hanan Almahasheer, Óscar Serrano, Carlos M. Duarte, Ariane Arias-Ortiz, Pere Masqué, Xabier Irigoien

Research outputs 2014 to 2021

Mangroves forests of Avicennia marina occupy about 135 km² in the Red Sea and represent one of the most important vegetated communities in this otherwise arid and oligotrophic region. We assessed the soil organic carbon (C_org) stocks, soil accretion rates (SAR; mm y^-1) and soil C_org sequestration rates (g C_org m^-2 yr^-1) in 10 mangrove sites within four locations along the Saudi coast of the Central Red Sea. Soil C_org density and stock in Red Sea mangroves were among the lowest reported globally, with an average of 4 ± …

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 …