Physical Sciences and Mathematics Commons^™

The Use Of Singlebeam Echo-Sounder Depth Data To Produce Demersal Fish Distribution Models That Are Comparable To Models Produced Using Multibeam Echo-Sounder Depth, Marcela Montserrat Landero Figueroa, Miles J. G. Parsons, Benjamin J. Saunders, Ben Radford, Chandra Salgado-Kent, Iain M. Parnum

Research outputs 2014 to 2021

Seafloor characteristics can help in the prediction of fish distribution, which is required for fisheries and conservation management. Despite this, only 5%–10% of the world's seafloor has been mapped at high resolution, as it is a time-consuming and expensive process. Multibeam echo-sounders (MBES) can produce high-resolution bathymetry and a broad swath coverage of the seafloor, but require greater financial and technical resources for operation and data analysis than singlebeam echo-sounders (SBES). In contrast, SBES provide comparatively limited spatial coverage, as only a single measurement is made from directly under the vessel. Thus, producing a continuous map requires interpolation to fill …

Thirty Critical Research Needs For Managing An Ecologically And Culturally Unique Remote Marine Environment: The Kimberley Region Of Western Australia, C. Cvitanovic, M. Mackay, R. Kelly, S. K. Wilson, K. Waples, K. L. Nash, E. I. Van Putten, S. Field, T. Botterill-James, B. J. Austin, L. E. Beckley, F. Boschetti, M. Depczynski, R. J. Dobbs, R. D. Evans, M. Feng, R. K. Goater, A. R. Halford, A. Kendrick, G. A. Kendrick, G. D. B. Lincoln, L. J. Ludgerus, R. J. Lowe, Kathryn Mcmahon, J. K. Munro, S. J. Newman, C. Nutt, L. Pearson, M. J. O'Leary, Z. T. Richards, W. D. Robbins, D. I. Rogers, Chandra P. Salgado Kent, V. Schoepf, M. J. Travers, M. Thums, A. D. Tucker, J. N. Underwood, S. Whiting, D. Matthews, Dambimangari Aboriginal Corporation

Research outputs 2014 to 2021

The Kimberley marine environment in Western Australia is widely recognised for its outstanding natural features, vast and remote sea and landscapes, and Indigenous cultural significance. To ensure that adequate baseline information is available to understand, monitor and manage this remote and relatively understudied region, scientific exploration was undertaken between 2012 and 2018 as part of the Kimberley Marine Research Program (KMRP). Whilst this program generated significant amounts of new knowledge about the region, important research gaps remain, that if answered, should improve the capacity of managers to conserve the region's values more effectively. Here, we apply established participatory horizon scanning …

Fire In Semi-Arid Shrublands And Woodlands: Spatial And Temporal Patterns In An Australian Landscape, Eddie Van Etten, Robert A. Davis, Tim S. Doherty

Research outputs 2014 to 2021

Semi-arid landscapes are of interest to fire ecologists because they are generally located in the climatic transition zone between arid lands (where fires tend to be rare due to lack of fuel, but are enhanced following large rainfall episodes) and more mesic regions (where fire activity tends to be enhanced following severe rainfall deficits). Here we report on the characteristics of the contemporary fire regimes operating in a semi-arid region of inland south-western Australia with rainfall averaging around 300 mm per annum. To characterize fire regimes, we analyzed a geodatabase of fire scars (1960–2018) to derive fire preferences for each …

Quantifying 210po/210pb Disequilibrium In Seawater: A Comparison Of Two Precipitation Methods With Differing Results, Montserrat Roca-Martí, Viena Puigcorbé, Maxi Castrillejo, Núria Casacuberta, Jordi Garcia-Orellana, J. Kirk Cochran, Pere Masqué

Research outputs 2014 to 2021

The disequilibrium between lead-210 (210Pb) and polonium-210 (210Po) is increasingly used in oceanography to quantify particulate organic carbon (POC) export from the upper ocean. This proxy is based on the deficits of 210Po typically observed in the upper water column due to the preferential removal of 210Po relative to 210Pb by sinking particles. Yet, a number of studies have reported unexpected large 210Po deficits in the deep ocean indicating scavenging of 210Po despite its radioactive mean life of ∼ 200 days. Two precipitation methods, Fe(OH)3 and Co-APDC, are typically used to concentrate Pb and Po from seawater samples, and deep …

The Role Of Aerodynamic Resistance In Thermal Remote Sensing-Based Evapotranspiration Models, Ivonne Trebs, Kaniska Mallick, Nishan Bhattarai, Mauro Sulis, Jamie Cleverly, William Woodgate, Richard Silberstein, Nina Hinko-Najera, Jason Beringer, Wayne S. Meyer, Zhongbo Su, Gilles Boulet

Research outputs 2014 to 2021

Aerodynamic resistance (hereafter ra) is a preeminent variable in evapotranspiration (ET) modelling. The accurate quantification of ra plays a pivotal role in determining the performance and consistency of thermal remote sensing-based surface energy balance (SEB) models for estimating ET at local to regional scales. Atmospheric stability links ra with land surface temperature (LST) and the representation of their interactions in the SEB models determines the accuracy of ET estimates. The present study investigates the influence of ra and its relation to LST uncertainties on the performance of three structurally different SEB models. It used data from nine Australian OzFlux eddy …

The Renaissance Of Odum's Outwelling Hypothesis In 'Blue Carbon' Science, Isaac R. Santos, David J. Burdige, Tim C. Jennerjahn, Steven Bouillon, Alex Cabral, Oscar Serrano, Thomas Wernberg, Karen Filbee-Dexter, Julia A. Guimond, Joseph J. Tamborski

Research outputs 2014 to 2021

The term ‘Blue Carbon’ was coined about a decade ago to highlight the important carbon sequestration capacity of coastal vegetated ecosystems. The term has paved the way for the development of programs and policies that preserve and restore these threatened coastal ecosystems for climate change mitigation. Blue carbon research has focused on quantifying carbon stocks and burial rates in sediments or accumulating as biomass. This focus on habitat-bound carbon led us to losing sight of the mobile blue carbon fraction. Oceans, the largest active reservoir of carbon, have become somewhat of a blind spot. Multiple recent investigations have revealed high …

Population-Specific Resilience Of Halophila Ovalis Seagrass Habitat To Unseasonal Rainfall, An Extreme Climate Event In Estuaries, Chanelle L. Webster, Kieryn L. Kilminster, Marta Sánchez Alarcón, Katherine Bennett, Simone Strydom, Sian Mcnamara, Paul S. Lavery, Kathryn M. Mcmahon

Research outputs 2014 to 2021

1. Extreme climate events are predicted to alter estuarine salinity gradients exposing habitat-forming species to more frequent salinity variations. The intensity and duration of these variations, rather than the mean salinity values ecosystems are exposed to, may be more important in influencing resilience but requires further investigation.
2. Precipitation, including the frequency, intensity and timing of occurrence, is shifting due to climate change. A global analysis on the timing of rainfall in estuarine catchments was conducted. In 80% of the case studies, the maximum daily rainfall occurred in the dry season at least once over the 40-year period and could be classified …

Evidence Of Large Increases In Sedimentation Rates Due To Fish Trawling In Submarine Canyons Of The Gulf Of Palermo (Sw Mediterranean), Sarah Paradis, Claudio Lo Iacono, Pere Masqué, Pere Puig, Albert Palanques, Tommaso Russo, The Island Cruise Tem

Research outputs 2014 to 2021

Bottom trawling in submarine canyons can affect their natural sedimentation rates, but studies addressing this issue are still scarce. In the Gulf of Palermo (SW Mediterranean), bottom trawling occurs on the slope around Oreto, Arenella and Eleuterio canyons. Analyses of excess 210Pb concentrations and grain size fractions in sediment cores from their canyon axes revealed that sedimentation rates and silt contents increased in all canyons in the 1980s, due to the expansion of more powerful trawlers ( > 500 HP) to deeper fishing grounds. In Eleuterio and Arenella canyons, sedimentation rates increased by an order of magnitude (0.1-1.4 cm·yr-1), whereas they …

Aquatic Ecosystems Of The Anthropocene: Limnology And Microbial Ecology Of Mine Pit Lakes, Melanie L. Blanchette, Mark A. Lund

Research outputs 2014 to 2021

Mine pit lakes (‘pit lakes’) are new aquatic ecosystems of the Anthropocene. Potentially hundreds of meters deep, these lakes are prominent in the landscape and in the public consciousness. However, the ecology of pit lakes is underrepresented in the literature. The broad goal of this research was to determine the environmental drivers of pelagic microbe assemblages in Australian coal pit lakes. The overall experimental design was four lakes sampled three times, top and bottom, in 2019. Instrument chains were installed in lakes and measurements of in situ water quality and water samples for metals, metalloids, nutrients and microbe assemblage were …

Genetic And Ecological Consequences Of Recent Habitat Fragmentation In A Narrow Endemic Plant Species Within An Urban Context, Nicola Delnevo, Andrea Piotti, Michele Carbognani, Eddie J. Van Etten, William D. Stock, David L. Field, Margaret Byrne

Research outputs 2014 to 2021

Understanding the timescales that shape spatial genetic structure is pivotal to ascertain the impact of habitat fragmentation on the genetic diversity and reproductive viability of long-lived plant populations. Combining genetic and ecological information with current and past fragmentation conditions allows the identification of the main drivers important in shaping population structure and declines in reproduction, which is crucial for informing conservation strategies. Using historic aerial photographs, we defined the past fragmentation conditions for the shrub Conospermum undulatum, a species now completely embedded in an urban area. We explored the impact of current and past conditions on its genetic layout …

A Temporal Record Of Microplastic Pollution In Mediterranean Seagrass Soils, Martin Dahl, Sanne Bergman, Mats Björk, Elena Diaz-Almela, Maria Granberg, Martin Gullström, Carmen Leiva-Dueñas, Kerstin Magnusson, Candela Marco-Méndez, Nerea Piñeiro-Juncal, Miguel Ángel Mateo

Research outputs 2014 to 2021

© 2021 Elsevier Ltd Plastic pollution is emerging as a potential threat to the marine environment. In the current study, we selected seagrass meadows, known to efficiently trap organic and inorganic particles, to investigate the concentrations and dynamics of microplastics in their soil. We assessed microplastic contamination and accumulation in 210Pb dated soil cores collected in Posidonia oceanica meadows at three locations along the Spanish Mediterranean coast, with two sites located in the Almería region (Agua Amarga and Roquetas) and one at Cabrera Island (Santa Maria). Almería is known for its intense agricultural industry with 30 000 ha of plastic-covered …

Kelp-Associated Microbes Facilitate Spatial Subsidy In A Detrital-Based Food Web In A Shoreline Ecosystem, Charu Lata Singh, Megan J. Huggett, Paul S. Lavery, Christin Säwström, Glenn A. Hyndes

Research outputs 2014 to 2021

Microbes are ubiquitous but our knowledge of their effects on consumers is limited in benthic marine systems. Shorelines often form hotspots of microbial and detritivore activity due to the large amounts of detrital macrophytes that are exported from other coastal ecosystems, such as kelp forests, and accumulate in these systems. Shoreline ecosystems therefore provide a useful model system to examine microbial-detritivore interactions. We experimentally test whether bacteria in the biofilm of kelp provide a bottom-up influence on growth and reproductive output of detritivores in shorelines where detrital kelp accumulates, by manipulating the bacterial abundances on kelp (Ecklonia radiata). The growth …

Dynamics And Fate Of Blue Carbon In A Mangrove–Seagrass Seascape: Influence Of Landscape Configuration And Land-Use Change, Maria E. Asplund, Martin Dahl, Rashid O. Ismail, Ariane Arias-Ortiz, Diana Deyanova, João N. Franco, Linus Hammar, Arielle I. Hoamby, Hans W. Linderholm, Liberatus D. Lyimo, Diana Perry, Lina M. Rasmusson, Samantha N. Ridgway, Gloria Salgado Gispert, Stéphanie D’Agata, Leah Glass, Jamal Angelot Mahafina, Volanirina Ramahery, Pere Masque, Mats Björk, Martin Gullström

Research outputs 2014 to 2021

Context: Seagrass meadows act as efficient natural carbon sinks by sequestering atmospheric CO and through trapping of allochthonous organic material, thereby preserving organic carbon (C ) in their sediments. Less understood is the influence of landscape configuration and transformation (land-use change) on carbon sequestration dynamics in coastal seascapes across the land–sea interface. Objectives: We explored the influence of landscape configuration and degradation of adjacent mangroves on the dynamics and fate of C in seagrass habitats. Methods: Through predictive modelling, we assessed sedimentary C content, stocks and source composition in multiple seascapes (km-wide buffer zones) dominated by different seagrass communities in …

Viral-Mediated Microbe Mortality Modulated By Ocean Acidification And Eutrophication: Consequences For The Carbon Fluxes Through The Microbial Food Web, Andrea Malits, Julia A. Boras, Vanessa Balagué, Eva Calvo, Josep M. Gasol, Cèlia Marrasé, Carles Pelejero, Jarone Pinhassi, Maria Montserrat Sala, Dolors Vaqué

Research outputs 2014 to 2021

Anthropogenic carbon emissions are causing changes in seawater carbonate chemistry including a decline in the pH of the oceans. While its aftermath for calcifying microbes has been widely studied, the effect of ocean acidification (OA) on marine viruses and their microbial hosts is controversial, and even more in combination with another anthropogenic stressor, i.e., human-induced nutrient loads. In this study, two mesocosm acidification experiments with Mediterranean waters from different seasons revealed distinct effects of OA on viruses and viral-mediated prokaryotic mortality depending on the trophic state and the successional stage of the plankton community. In the winter bloom situation, low …

Morphological And Heartwood Variation Of Santalum Macgregorii In Papua New Guinea, T. Page, G. K. Jeffrey, P. Macdonell, D. Hettiarachchi, Mary C. Boyce, A. Lata, L. Oa, G. Rome

Research outputs 2014 to 2021

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Santalum macgregorii (sandalwood), which is endemic to the southern part of Papua New Guinea (PNG), has been heavily exploited for its fragrant heartwood and is classified as threatened across its natural range. Domestication and smallholder agroforestry offer the means to preserve remaining diversity. This study was undertaken to understand the extent of remaining natural variation to support the species’s conservation and domestication. We evaluated morphological, heartwood and essential oil characters in 126 S. macgregorii trees in five populations (districts) in PNG’s Central, Gulf and Western …

Distribution And Evolution Of Fukushima Dai-Ichi Derived 137cs, 90sr, And 129i In Surface Seawater Off The Coast Of Japan, Jennifer A. Kenyon, Ken O. Buesseler, Núria Casacuberta, Maxi Castrillejo, Shigeyoshi Otosaka, Pere Masqué, Jessica A. Drysdale, Steven M. Pike, Virginie Sanial

Research outputs 2014 to 2021

© 2020 American Chemical Society. The Fukushima Dai-ichi Nuclear Power Plants (FDNPPs) accident in 2011 led to an unprecedented release of radionuclides into the environment. Particularly important are 90Sr and 137Cs due to their known health detriments and long half-lives (T1/2 ≈ 30 y) relative to ecological systems. These radionuclides can be combined with the longer-lived 129I (T1/2 = 15.7 My) to trace hydrologic, atmospheric, oceanic, and geochemical processes. This study seeks to evaluate 137Cs, 90Sr, and 129I concentrations in seawater off the coast of Japan, reconcile the sources of contaminated waters, and assess the application of 137Cs/90Sr, 129I/137Cs, and …

Modeling Organic Carbon Accumulation Rates And Residence Times In Coastal Vegetated Ecosystems, E. Fay Belshe, Jose Sanjuan, Carmen Leiva-Dueñas, Nerea Piñeiro-Juncal, Oscar Serrano, Paul Lavery, Miguel Angel Mateo

Research outputs 2014 to 2021

Coastal vegetated “blue carbon” ecosystems can store large quantities of organic carbon (OC) within their soils; however, the importance of these sinks for climate change mitigation depends on the OC accumulation rate (CAR) and residence time. Here we evaluate how two modeling approaches, a Bayesian age-depth model alone or in combination with a two-pool OC model, aid in our understanding of the time lines of OC within seagrass soils. Fitting these models to data from Posidonia oceanica soil cores, we show that age-depth models provided reasonable CAR estimates but resulted in a 22% higher estimation of OC burial rates when …

Tracing Water Masses With 129i And 236u In The Subpolar North Atlantic Along The Geotraces Ga01 Section, Maxi Castrillijo, Núria Casacuberta, Marcus Christl, Christoph Vockenhuber, Hans A. Synall, Maribel I. García-Ibáñez, Pascale Lherminier, Géraldine Sarthou, Jordi García-Orellana, Pere Masqué

Research outputs 2014 to 2021

Pathways and timescales of water mass transport in the subpolar North Atlantic Ocean (SPNA) have been investigated by many studies due to their importance for the meridional overturning circulation and thus for the global ocean. In this sense, observational data on geochemical tracers provide complementary information to improve the current understanding of the circulation in the SPNA. To this end, we present the first simultaneous distribution of artificial 129I and 236U in 14 depth profiles and in surface waters along the GEOVIDE section covering a zonal transect through the SPNA in spring 2014. Our results show that the two tracers …

Key Biogeochemical Factors Affecting Soil Carbon Storage In Posidonia Meadows, Oscar Serrano, Aurora M. Ricart, Paul S. Lavery, Miguel-Angel Mateo, Ariane Arias-Ortiz, Pere Masque, Mohammad Rozaimi, Andy D. L. Steven, Carlos Duarte

Research outputs 2014 to 2021

Biotic and abiotic factors influence the accumulation of organic carbon (C_org) in seagrass ecosystems.We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of C_org. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4m depth) accumulated 3- to 4-fold higher C_org stocks (averaging 6.3 kgC_org m^-2) at 3- to 4-fold higher rates (12.8 gC_org m^-2 yr^-1/ compared to meadows closer to the deep limits of distribution …

Asal Usul Formasi Savana: Tinjauan Dari Nusa Tenggara Timur Dan Hasil Penelitian Di Baluran Jawa Timur [Origin Of Savanna Formation: Literature Review From East Nusa Tenggara And Research Results From Baluran East Java Indonesia], Sutomo

Research outputs 2014 to 2021

Savannas are ecosystems mostly confined to tropical and subtropical regions that are characterized by a continuous cover of C₄ grasses that have different characteristics based on seasonality and where woody plants are also an important feature, but with sparse cover and no closed canopy. This is common formation in the driest part of Indonesia such as East Nusa Tenggara, however savana can also be found in Java Island: Baluran Savanna in East Java. There has been considerable amount of debat among scientists, botanists in Indonesia regarding the origin of Indonesian savanna. Using literature study and also field observation at …

Seagrass Meadows As A Globally Significant Carbonate Reservoir, I Mazarrasa, N Marbà, O Serrano, C E. Lovelock, Paul S. Lavery, J W. Fourqurean, H Kennedy, M A. Mateo, D Krause-Jensen, A D. Steven, C M. Duarte

Research outputs 2014 to 2021

There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass …

Do Water Buffalo Facilitate Dispersal Of Invasive Alien Tree Species Acacia Nilotica In Bekol Savanna Baluran National Park?, Sutomo

Research outputs 2014 to 2021

Invasion of Acacia nilotica in Baluran National Park, East Java Province, Indonesia, has caused significant loss to savanna cover which is the main natural feature of the park. This study aimed to describe whether water buffalo may play a role in the dispersal of Acacia nilotica seed in Bekol Savanna usinganalysis of buffalo stools/scats, observations and seed experiments. In total there were 30 plots set up around the Bekol Savanna to collect buffalo stools. In addition,A. nilotica pods matured from its trees were collected, as controls. Germination tests were conducted on seeds that were extracted from the collected stools …

Soil Seed Banks Of Fringing Salt Lake Vegetation In Arid Western Australia - Density, Composition And Implications For Postmine Restoration Using Topsoil, Eddie J. Van Etten, Brett Neasham, Sarah Dalgleish

Research outputs 2014 to 2021

Although studies of seed banks in arid ecosystems are commonplace, they are lacking for the large arid zone of Western Australia. Across the six major plant communities fringing a large salt lake within this zone, topsoil (0-5 cm depth) was collected from 12 to 36 sites per community. Samples were dried, spread out on a bed of vermiculite in seedling trays and placed in a well-watered glasshouse to determine the readily germinable component of the soil seed bank. Subsamples of topsoil were treated with smoke water, hot water or flooding to help determine seed bank of species with dormancy mechanisms. …