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Benthic Ecology Group

Research

  

The Benthic Ecology lab research projects aim to explore the interaction between benthic ecosystems and natural and human-induced environmental change. They seek to determine those processes that act to maintain biodiversity, and its important ecosystem functions, and the mechanisms by which these processes are destablised.


If you would like to know more or would like to contact the individual reasearchers visit our "People" page.

 

Genetic solution or genetic dilution?

The Brown World View

Sustained Nutrient Loading

Estuarine Acidification

Multiple stressor effects

Facilitation cascades

Beach nourishment

Towards sustainable seawalls 

 

 

              Eco-engineering 

 

 

Invasive species

 

 

 

 Genetic solution or genetic dilution?

This project is testing whether the flow of beneficial genes from farmed oysters into wild oysters can make natural oyster beds and the ecological communities that they support more resilient to environmental change. Wild oysters are critical to the function of coastal ecosystems. However, their populations are threatened by environmental change in Australia and around the world. Selectively bred oysters bearing stress resistance genotypes are now commercially farmed in many estuaries on Australia’s east coast and may be used to bolster wild oyster populations. In developing novel genetic strategies to future-proof oysters, this work will benefit entire ecosystems that depend upon oysters.

 

Please contact Dr Melanie Bishop regarding this research via the "People" page

 

 

 

 

  

The Brown World View

 

In aquatic ecosystems, most primary production is not consumed by herbivores but instead enters detrital pathways. This detritus (dead organic matter) is frequently transported across habitat boundaries, and far from its source, by wind, waves, and currents. Depending on where it is transported to and accumulates, detritus may be broken down by bacteria, fungi and detritivores to liberate carbon and nutrients that fuel food webs. Alternatively it may be buried in anoxic sediments where it can be locked away for millennia, serving as an important carbon store. Over the past ten years, Melanie and her team have been researching how the traits of aquatic primary producers and environmental conditions interact to influence the fate of detritus, and how the supply, quality and mix of detritus influences it value to sediment-dwelling communities. Her team has:

•    Determined how different detrital sources are utilized by consumers, and when mixed interact synergistically to influence consumer productivity (Bishop and Kelaher 2008, 2013)
•    Shown that increased mobilisation and supply of detritus under enhanced storminess will reduce coastal productivity by depleting sediments of oxygen (Bishop and Kelaher 2007)
•    Demonstrated for the first time that species extinctions can modify spatially removed ecosystems by changing the detrital resources they receive (Bishop et al. 2010) ·
•    Provided experimental evidence that when the Class I noxious species, Caulerpa taxifolia, gets washed onto the shore and decomposes, the detritus it creates can adversely affect invertebrates living in intertidal sediments (Taylor et al. 2010)

This research has revolutionised how detritus is treated in food web models that previously considered it a static and homogenous resource. 

 

Please contact Dr Melanie Bishop regarding this research via the "People" page

 

 

 

 

 

 Impacts of Sustained Nutrient Loading 

Urbanization, waste disposal and the application of fertilizer within adjacent watersheds has led to nutrient enrichment of coastal ecosystems. Elevated nutrients stimulate the productivity of fast-growing aquatic plants, in some instances facilitating fisheries productivity and in others leading to ecosystem collapse where the rapid decomposition of large quantities of organic material (detritus) starves sediments of oxygen. Our research has greatly enhanced our understanding of when and where impacts of nutrient enrichment shift from positive to negative. We have found that contrary to the paradigm that nutrient enrichment leads to ecosystem collapse, along the east coast of Australia, moderate nutrient enrichment of naturally low-nutrient estuaries enhances productivity at all levels of the food web (phytoplankton or epiphytes, macroinvertebrates, invertebrate-feeding fishes, piscivorous fishes; Bishop et al. 2006; York et al. 2012; Kelaher et al. 2013). Our results are influencing catchment management (Hawkesbury Estuary, Hornsby Shire Council, NSW).Enhanced CO2 emissions are acidifying the oceans, yet resulting changes to marine life are poorly understood. 

 Please contact Dr Melanie Bishop regarding this research via the "People" page

 

 

 


 

Acid test for the Capacity of Estuaries to Adapt to Climate Change

Enhanced CO2 emissions are acidifying the oceans, yet resulting changes to marine life are poorly understood. Most studies examining impacts of ocean acidification have been conducted in small aquaria that lack the scale or complexity of natural ecosystems, and on organisms naïve to the stressor. We have been combining ecological and molecular tools to assess the extent to which acid-sulfate acidification of estuaries, a problem which for years has affected east Australian waters might help inform future impacts of CO2-acidification. We have shown that despite the pH in acid-sulfate acidified estuaries commonly falling way below predictions for even the worst case scenario under climate change, oysters and other calcifying molluscs are able to persist (e.g. Amaral et al. 2011a,b, 2012a,b). We have shown that there are strong molecular signals of acid-sulfate acidification among oysters (Amaral et al. 2012), that map to key physiological responses.

 Please contact Dr Melanie Bishop regarding this research via the "People" page.

 



Multiple stressor effects
 

 

This work is being undertaken as part of a PhD by Mrs Ramila Furtardo, under the supervision of Dr Melanie Bishop and Dr Leanne Armand.

 


 

Facilitation cascades

 

 

 Please contact Dr Melanie Bishop regarding this research via the "People" page.
 


 

Shoreline Protection at what Cost: Ecological Impacts of Beach Nourishment.

 

Beach nourishment involves taking sediment from an external fill site and depositing it on an eroding beach to elevate it and extend it seaward. It is increasingly being used in Australia (Cooke et al. 2012) and many other parts of the world to protect coastal properties and public beach amenity from rising sea-levels and shoreline erosion. In collaboration with colleagues at the University of North Carolina at Chapel Hill we have been conducting some of the first assessments of the mechanisms by which beach dredge-and-fill projects impact sandy beach ecosystems. Despite the presumption that sandy beach biota are well adapted to physical disturbance, we have shown that beach nourishment projects that occur during the peak reproductive season of sandy beach invertebrates or coarsen sediment grain-size (Peterson et al. 2014) can have impacts on sandy beach invertebrates that persist for years. These impacts propagate up to reduce the number of foraging shorebirds beaches can sustain (Peterson et al. 2014). Further, where beach nourishment leads to turbidity plumes it can interfere with visual surf fish foraging (Manning et al. 2014). Our papers are not only drawing attention to the ecological impacts nourishment can have on sandy beach invertebrates, but also provide recommendations to coastal managers as to how future nourishment projects can be conducted to ensure the sustainability of sandy beach ecosystems.

Please contact Dr Melanie Bishop regarding this research via the "People" page.

 


 


 

Towards sustainable seawalls: assessing how the design of hard engineering structures influences sandy beach ecosystems

 

Coastal environents of south-eastern Australia are among the ecosystems most threatened by the direct effects of climate change and the indirect effects resulting from the adaptation of human settlements. Coastal armouring structures, such as sea walls are designed to restrict coastal erosion and provide protection to infrastructure and development. The physical impact and biological response to coastal armouring will be influenced by the position of the structure on the shore relative to breaking waves and swash as well as the design of the structure.
 
This current study is a collaboration with the University of NSW, funded by the Coastal Processes and Responses Node of the Climate Adaptation Research Hub of NSW Office of Environment and Heritage. The study examines physical and biological variation along the shoreline at a number of unarmoured and armoured sites of varying design. The findings of this study will inform about the ecological responses to coastal armouring and will assist in the refinement of adaptation options for coastal settlements to conserve ecosystem values of these systems.


Please contact Dr Belinda Cook regarding this research via the "People" page.

  

     

                                Sandy Beach Macroinvertebrate Photos (J. Rowland): a) Isopod, b) and c) Polychaete

                                                 

Sandy Beach Meiofauna Photos (B. Cooke): a) Flatworm (Plathyhelminthes), b) Copepod

         

Coastal armouring along Belongil Beach NSW (B. Cooke)

 

 

   Trophic ecology of invasive Euopean shore crab, Carcinus maenas, in Australian estuaries

The invasion of exotic species i widely accepted as being one of the major causes of theloss of both native species and biodiversity worldwide. The European shore crab, Carcinus maenas, is one of the world's 100 worst invasive species. It invaded Australian waters over a century ago and poses a considerable threat to Australian coastal ecosystems.

 

The current project examines the trophic interactions between the invasive shore crab and native australian prey and competitors. Assesisng C. maenas' potential impact on Australian coastal ecosystems, and determining whether:

  1. Prey species are able to defend themselves and
  2. Native decapod species are able to out-compete this exotic pest. 

 

This work is being undertaken as part of a PhD degree by Mr Danial Bateman under the supervision of Dr Melanie Bishop.

 

 

 

 

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