Modelling a picture of the future Kimberley marine environment

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Scientists are working on the final stage of developing models that could estimate the likely effect of changes in population, tourism and climate in the Kimberley to better predict what the future may look like.

By the end of the Western Australian Marine Science Institution’s Kimberley Marine Research Program (KMRP), a staggering 25 research projects will have generated new information about the bio-physical, ecological and social processes affecting the Kimberley marine environment and the main causes of change.

Condensing all this information into a unified picture to better understand the complex interactions to guide conservation decisions is an international team of researchers from CSIRO and ALCES (based in Canada).

Led by CSIRO’s Dr Fabio Boschetti, the team has been building a modelling tool which uses the best available information on the likely future of the region.

 

Simplified, spatially explicit, conceptual model of the working of the Kimberley system, including land, coastal and marine processes

“In general, model predictions are more reliable than the ones we (experts included) may produce without models,” Dr Boschetti said. “Of course, models will not accurately predict what will happen to the system. Rather, they are designed to say something physically and ecologically meaningful about what may happen to the system, should it undergo specific pressures.”

“They are tools which allow us to integrate the available knowledge, include the state-of-the-art understanding of social, economic and ecological processes and account for uncertainty and missing information. We can use them to explore what may happen to the Kimberley region to the year 2050 depending on how the Kimberley system works, what events may occur, and what we do and how we react to these events. Hypothetical or conditional questions, like “if this event occurs, then what may the future look like?’ can be asked. This forces us to focus on the events and conditions which may affect it,” Dr Boschetti said.

Modelling approach based on asking what may happen to the Kimberley region if specific events (scenarios) occur and specific initiatives (management strategies) are adopted

The two computer models are being used in this project to integrate existing knowledge about the Kimberley system to provide an estimation of the likely impacts of different stressors on the land (ALCES) and marine (Ecopath with Ecosim – EwE) environments.

The EwE model is being used to characterise the impact of fishing, tourism, other human uses and climate change on the Kimberley marine ecosystem as well as how different management options, such as controls on fishing effort and spatial closures, can affect the overall impact.

Based on available information on likely future land use in the Kimberley (e.g. mining, energy, aquaculture, crops, livestock, settlements, tourism, transportation) ALCES can simulate how land based processes affect the marine environment via sediment and pollution flows, infrastructure and localised human pressure.

“We do not know precisely how the Kimberley system works, but we have a few working hypothesis that represent a snapshot of how we believe the system is and works now,” Dr Boschetti explained.

“A future is an estimation of what the system may look like several years down the track, according to the model,” Dr Boschetti said. “It is the answer to the question ‘If a specific scenario occurs and we implement a specific management strategy and the system works according to our current knowledge, then how will the system likely respond?”

Determining future outcomes is the final stage of the project to be delivered by October 2017.

More information can be found on the WAMSI KMRP Modelling Project Page: www.wamsi.org.au/modelling-future-kimberley-region

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Northwest Australia reveals its unique marine ecosystem

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While unusually warm sea temperatures in the Kimberley region threaten to cause further coral bleaching between April and May, researchers have joined with the Bardi-Jawi Land and Sea Rangers to provide the first detailed look into the process of fish and coral replenishment and the importance of marine plants in the ecosystem.

By the end of the Western Australian Marine Science Institution’s Kimberley Marine Research Program (KMRP) project a team of researchers from five separate institutions will have answered some important questions about this unique environment such as: When do young corals and fish move from the open ocean back into shallow coastal waters? Where do they go? Are there important “nursery” habitats or areas that need protection? Who is responsible for eating the majority of plant material? How much do they eat?

Scientists from the Australian Institute of Marine Science (AIMS), CSIRO, Department of Parks and Wildlife WA (Parks and Wildlife), The University of Western Australia (UWA), Department of Fisheries (DoF) and Western Australian Museum (WA Museum) are working in partnership with the Bardi Jawi Land and Sea Rangers, Traditional Owners (TO’s) and the Kimberley Marine Research Station to provide the first quantitative estimates of coral and fish recruitment and herbivory in the Cygnet Bay / Sunday Island group of the southern Kimberley region.

Study area (Kimberley region)

The core goal of the project is not only to provide primary information on these processes but a blueprint on the appropriate techniques needed to continue to learn what is ‘normal’ in this environment.

“This is one of the first studies in which recruitment has been measured during each month of the year, rather than focusing on one or two months following predicted periods of coral spawning,” AIMS Coral Researcher Dr James Gilmour said. “We have therefore captured periods of spawning outside of those predicted, and also the recruitment of ‘brooded’ larvae – those produced following the fertilisation and development of larvae within the coral’s polyp.

“Initial results indicate that patterns of reproduction at the inshore Kimberley reefs are similar to those offshore, but with more recruitment occurring in some winter and summer months. This is a likely consequence of spawning by some corals, such as the massive Porites bommies, outside of the mass-spawning period in autumn, and also indicates that brooding corals that release larvae throughout much of the year are a significant component of the Kimberley reefs.

“The effect of the mass-bleaching was obvious, dramatically reducing rates of coral recruitment below those expected. These data also provide a useful baseline with which to assess the recovery of coral recruitment in coming years,” Dr Gilmour said.

 

Isopora (left) and Porites (right) coral recruits on terracotta settlement plates. (AIMS)

 

Project leader Dr Martial Depczynski (AIMS) looked at fish recuitment and found generally, recruitment was stronger during the wet season, consistent with other Western Australian ecosystems.

“Although this seasonal pattern was consistent among habitats, each habitat consisted of a unique assemblage of fishes which also varied widely in abundance,” Dr Depczynski said.

“Mangroves uniquely provided a nursery habitat for some very important species such as the snappers Mangrove jack (Lutjanus argentimaculatus – Maarrarn) and Moses perch (Lutjanus russellii).

“Similarly for seagrasses, the Golden-lined rabbitfish (Siganus lineatus – Barrbal) that provide an important source of food were found almost exclusively in seagrass habitats,” Dr Depczynski said.

The research team recorded rates of grazing on seagrass that were higher in the southern Kimberley than anywhere else in the world.

“Average consumption of the seagrass Thalassia hemprichii, otherwise known as turtlegrass, actually outstripped growth in some areas, demonstrating how important seagrass is as a food source,” CSIRO’s Dr Mat Vanderklift said.

 

Grazed turtle grass (Thalassia hemprichii). Turtle grass is a fast grower but in some places grazing by herbivores exceeded estimates of production. (Mat Vanderklift, CSIRO)

 

“What we’ve been able to confirm so far is that differences in species groups vary greatly between habitats meaning that all habitat types in at least the southern Kimberley are equally important,” Dr Depczynski said.

“Also, fish diversity overall was surprisingly low and well below expectations considering its closer proximity to the equator and global centre of fish diversity prompting further questions about the influence of the Kimberley’s unique characteristics and how they affect recruitment processes,” Dr Depczynski said.

The final report is due to be completed mid-2017.

More information can be found on the WAMSI KMRP Key Ecological Processes project Page:  www.wamsi.org.au/key-ecological-processes

 

Graphical representation summarizing findings from juvenile fish stereo RUV surveys during the wet (top panel) and dry (bottom panel) seasons across five habitat types (mangrove, seagrass, algae, coral and inter-tidal pools; separated by dashed lines). Habitats portrayed from left to right follow a typical Kimberley habitat profile from inter-tidal mangroves to adjacent seagrass meadows and algal fields to elevated rocky inter-tidal pools and submerged coral reefs. Colour shades in the background of each habitat represent groupings based on observed statistical differences in fish assemblages among habitats (brown-mangroves, green-seagrass, and pink- algae, coral and inter-tidal pools). Each fish diagram represents a different juvenile species; key to right shows scientific and Bardi Jawi names. Only the ten most abundant and highly influential species distinguishing between fish assemblages are presented. The number of fish in each panel is equivalent to the average number of juvenile fish per RUV replicate (e.g. MaxN = 5 in mangrove habitat during the wet season).

 

Key Ecological Processes project page: www.wamsi.org.au/key-ecological-processes

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

WAMSI congratulates CEO Patrick Seares on new role

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Scientists test new sediment sensor that mimics coral reef

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Scientists have tested a breakthrough in sensing sediment risks to reefs that uses bundles of fibre optic sensors and hundreds of countersunk holes to mimic coral.

Sedimentation is considered one of the most widespread causes of stress on coral reefs, and researchers are working to understand the patterns of suspension and resuspension caused by wind, wave, catchment run-off and dredging related activity to better inform about the environmental risks.

The newly designed sediment sensor, has 15 separate fibre optic bundles that produce three separate measurements, each an average of five bundles, and the three-millimetre-thick plate is perforated with hundreds of countersunk apertures, the size and spacing designed to mimic coral. The shape allows sediment to be naturally resuspended by wave action in a similar way to that which would occur on a coral.

(Whinney J, Jones R, Duckworth A, Ridd P (Dec 2016) Continuous in situ monitoring of sediment deposition in shallow benthic environments Coral Reefs DOI 10.1007/s00338-016-1536-7)

The sensor was tested as part of a Western Australian Marine Science Institution Dredging Science Node project against different conditions in the Australian Institute of Marine Science (AIMS) National Sea Simulator (SeaSim) laboratory and in the highly turbid inshore reef community of the Great Barrier Reef (GBR).

Researchers from James Cook University and AIMS were able to show previously undescribed patterns of sediment deposits on reef in the turbid coastal central GBR over periods of a few hours rather than averages over days or weeks, giving a greater understanding of the behaviour of one of the key pollutants on coral reefs.

“The in-situ deployment covered a range of physical conditions with peaks in sedimentation occurring after peaks in turbidity and waves when material began to settle out of suspension,” lead researcher, Dr James Whinney said. “The daily average sediment deposition rate was 19 ± 15 mg cm-2 d-1 over the deployment.”

“However, while Sedpods offer a low cost alternative to measure rates of sedimentation, they do not self clean and need to be changed over each day which involves the logistical and financial costs of daily boating and diving to collect and redeploy.

“The next stage is to carry out testing further offshore as well as during dredging campaigns to define the range of sediments rates corals are likely to experience,” ” Dr Whinney said.

Earlier versions of the deposition sensor used in this study have been deployed in Japan, Papua New Guinea and the inshore central GBR (Thomas et al. 2003a; Thomas and Ridd 2005).

 

 

Whinney J, Jones R, Duckworth A, Ridd P (Dec 2016) Continuous in situ monitoring of sediment deposition in shallow benthic environments Coral Reefs DOI 10.1007/s00338-016-1536-7

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

Can Environmental Windows be effective in managing effects of dredging?

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An examination of whether dredging operations suspended during generic windows of environmental sensitivity could reduce the impacts on marine life has found the marine invertebrates, seagrasses and macroalgae too diverse to be covered by a one-size-fits-all approach.

An international team of researchers were involved in the review for the Western Australian Marine Science Institutions’ Dredging Science Node. Lead researcher, Dr Matthew Fraser from The University of Western Australia’s (UWA) Oceans Institute, said the results helped to clarify whether there was enough scientific evidence to base the timing of dredging operations outside a set of generic Environmental Windows.

“The project was basically tasked with looking at whether avoiding or reducing dredging during sensitive life history periods may help to minimise dredging impacts, and we used Western Australia as a case study,” Dr Fraser said. “The problem is that we don’t know enough about reproduction, planktonic dispersal and recruitment for many benthic marine organisms in Western Australia.”

 

Western Australia is a hotspot for macroalgal diversity. Slow growing macroalgae are considered as having higher vulnerabilities to dredging impacts. (Matthew Fraser) Chromodoris westraliensis (Nudibranch) at Cottesloe Reef. (Matthew Fraser)

 

“Combine this knowledge gap with species-specific timing of these events suggests a generic environmental window does not protect all species,” co-author UWA’s Professor Gary Kendrick said.

“What this means is that selection and management of Environmental Windows are best considered on a location by location basis with priority given to ecologically and economically important species that we know enough about,” Dr Fraser said.

 

Western Australian seagrasses form important habitat that supports diverse assemblages of marine animals. Slow growing seagrasses such as Posidonia australis (above) are at higher risk from dredging impacts than faster growing seagrasses. (Matthew Fraser)

 

Fraser MW, Short J, Kendrick GA, McLean D, Keesing J et al. Effects of dredging on critical ecological processes for marineinvertebrates, seagrasses and macroalgae, and the potential for management with environmental windows using Western Australia as a case study Ecological Indicators http://dx.doi.org/10.1016/j.ecolind.2017.03.026

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

Everything you ever wanted to know about how dredging impacts fish!

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Early stages of fish life, such as eggs and larvae, are most likely to suffer lethal impacts from dredging-related stress, while adult fish that migrate from fresh water to the sea to spawn (catadromous fishes) are more likely to change behaviour, according to new research.

A team led by University of Queensland postdoctoral researcher Amelia Wenger examined hundreds of studies to determine how dredging related stressors, including suspended sediment, contaminated sediment, hydraulic entrainment (organisms that get sucked up with the sediment) and underwater noise, directly influence the size of the effect and response in fish across all aquatic ecosystems and all life history stages.

The Western Australian Marine Science Institution Dredging Science Node project, found that across all dredging-related stressors, studies that reported fish mortality had significantly higher effect sizes than those that describe physiological responses, though indicators of dredge impacts should aim to detect effects before excessive mortality occurs.

“Both suspended sediment concentration and duration of exposure greatly influenced the type of fish response we observed, with both higher concentrations and longer exposure associated with fish mortality,” Dr Wenger said.

 

(Figure 1. A schematic diagram of categories of potential effects of dredging on fish. – Wenger AS, Harvey E, Wilson S, et al. A critical analysis of the direct effects of dredging on fish. Fish Fish. 2017;00:1–19. https://doi.org/10.1111/faf.12218)

 

“It’s well known that some fish avoid turbid waters but moving to a less ideal environment can affect their chances of survival. Increasing exposure to suspended sediment makes it harder for fish to find their food, elevates their stress levels, and causes damage to fish gills affecting growth, development and swimming ability.

“By analysing several studies, we were able to see clear evidence that fish from all aquatic ecosystems were sensitive to turbidity,” Dr Wenger said.

Studies examining the effects of contaminated sediment also had significantly higher effect sizes than studies on clean sediment alone or noise, suggesting combined dredging stressors produce an effect greater than the sum of their individual effects.

“The review highlights the need for in-situ studies on the effects of dredging on fish which consider the interactive effects of multiple dredge stressors and their impact on sensitive species of ecological and fisheries value,” Dr Wenger said.

The findings are expected to improve the management of dredging projects to ultimately minimise their impacts on fish.

 

Wenger AS, Harvey E, Wilson S, et al. A critical analysis of the direct effects of dredging on fish. Fish Fish. 2017;00:1–19. https://doi.org/10.1111/faf.12218

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

The underwater world of the Kimberley

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Renowned for its extreme tides, the waters of the Kimberley host seagrass and microalgae that thrive against the odds. A three-year study combined science and traditional knowledge to uncover some of the secrets of these fascinating species, and the herbivors that feed on them.

Click here to read the full article by Mat Vanderklift and Gary Kendrick in Landscope  

 

Category: 

Kimberley Marine Research Program

Results released on seagrass responses to dredging in northwest Australia

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Three new reports have been released on the primary producer responses to dredging.

There is almost no knowledge of how seagrass primary producers in the northwest of Australia will respond to the environmental changes produced by dredging. Consequently, it is difficult to predict and then manage the impacts of dredging on these critical habitats with an acceptable level of certainty.

Research within the Western Australian Marine Science Institution (WAMSI) Dredging Science Node focuses on two of the most significant stresses produced by dredging: the reduction in light availability to plants; and the smothering of seagrass and algae as suspended sediments settle.

Project leader Kathryn McMahon from Edith Cowan University and team members from The University Australia, Department of Parks and Wildlife WA and The University of Adelaide have looked at three key areas:

  1. Seagrasses of the northwest of Western Australia: biogeography and considerations for dredging-related research;
  2. The current state of knowledge regarding the effects of dredging-related ‘pressure’ on seagrasses using information compiled from unpublished industry data, as well as published reports, articles and books; and
  3. Genetic variability within seagrass of the northwest of Western Australia

The first project identified five dredging related stressors that are likely to directly impact seagrass habitat and prioritised the top three in the following list that are of most interest for impact prediction and management of dredging events:

  • reduced benthic light quantity;
  • burial by sediment;
  • sediment anoxia and increased hydrogen sulfide production;
  • altered benthic light quality (i.e. spectral characteristics); and
  • increased suspended sediment

It identified knowledge gaps in three key areas:

  • How dredging affects environmental conditions that are likely to impact seagrass.
  • Thresholds for dredging-related stressor beyond which seagrasses will be affected; and
  • Monitoring during dredging campaigns.

The second project identified the seagrass species Halophila ovalis, Halodule uninervis and Cymodocea serrulata, as the focus of subsequent research into thresholds and indicators of response to dredging-related pressures.

The third study is the first of its kind to examine the patterns of genetic diversity in seagrasses in the Pilbara region which strongly influences their ability to adapt to, resist or recover from these pressures.

This study identified  that:

  1. Most meadows examined  had  relatively  high  clonal  diversity  (i.e.  many  unique  individuals in the meadow), so both sexual reproduction and vegetative growth are important for maintaining these populations; and
  2. There was a reasonably high level of migration of genes over distances of 2−5km, but lower levels over  greater  distances. The  study  also  showed  that  not  all  seagrass  meadows  and  species  in NW Australia  have  a  similar  level  of  genetic  diversity. This information should be incorporated into management decisions as the level of genetic diversity has implications for the ability of populations to resist and recover from disturbance.

The WAMSI Dredging Science Node is one of the largest single issue research programs in Australia meeting the needs of the State Government and industry to improve their understanding of how key primary producers are affected by dredging-related pressures.

The full reports can be found on the WAMSI DSN Primary Producer project page

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

 

Category:

Dredging Science