Marine Biology 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 …

Journal Of Ecology 2021 Global Rainfall-Seagrass Resilience-Swan River, Chanelle L. Webster, Kathryn M. Mcmahon, Paul S. Lavery, Simone Strydom, Marta Sánchez Alarcón, Kieryn L. Kilminster, Katherine Bennet, Sian Mcnamara

Research Datasets

The excel file contains: summary of daily maximum precipitation from global rainfall analysis, monthly change in seagrass indicators (biomass, leaf density etc); water quality data including salinity, temperature and light data. There are also .nc files containing precipitation data from 1979-2019.

The Distribution And Trophic Ecology Of Golden Ghost Crabs (Ocypode Convexa), Caitlin Rae

Theses: Doctorates and Masters

Sandy beaches make up approximately three-quarters of the world’s shorelines. They are important ecosystems, hosting abundant invertebrate macrofaunal communities that provide food resource for vertebrate predators such as shorebirds, seabirds, marine mammals and fish. Although possessing a terrestrial appearance, food input on sandy beaches is derived predominantly from the sea. Such food input includes detrital matter, mostly in the form of wrack, and has the potential to support a great diversity of species, as well as stabilising energy fluxes and dynamics of consumer populations. The movement of detritus, along with other vectors such as organisms and nutrients, across ecosystem boundaries …

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 …

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 …

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 …

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 …

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 …