Can dredging sediments affect the reproductive cycle of corals?

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A new review has found that turbidity and sedimentation, two of the most widely recognised threats to coral reefs, can have an effect on coral reproduction before, during and after spawning.

Elevated turbidity regularly occurs in shallow, tropical marine environments driven primarily by wind-driven waves but this can be exacerbated by anthropogenic activities such as dredging. The effects on adult corals and the sensitivity of their early life-history stages has been well documented, but the review, published in Marine Pollution Bulletin highlights new potential mechanisms that suspended sediments can have on the reproductive cycle including gametogenesis, spawning synchrony and on gametes in the water column.

The WAMSI study, conducted by researchers from the Australian Institute of Marine Science (AIMS) and The University of Western Australia (UWA), is working to help environmental managers predict how corals will react to changing pressures on their environment.

Co-author from UWA’s Centre for Microscopy, Characterisation and Analysis, Gerard Ricardo, said the review highlighted the need to be able to quantify the extent of the changes in the environment in order to accurately predict how coral spawning would be affected.

WAMSI researcher Gerard Ricardo (UWA) collecting freshly spawned eggs for laboratory experimentation. (AIMS)

“This review was partly motivated by the recent resources boom in tropical Australia, the need for dredging for coastal infrastructure and shipping channels to export mineral and petroleum products, and current environmental regulations around protecting coral spawning events during dredging campaigns,” Gerard explained. “However, the findings are equally as applicable to natural events in turbid-zone communities driven by wind-wave induced resuspension.”

Lead author AIMS’ Dr Ross Jones said that while sediments can act as an energy source for adult corals, there are overwhelmingly more than 30 possible causal pathways whereby turbidity-generating activities can negatively affect reproduction and early life-cycle stages.

“We know that it is only very subtle changes in light quantity and quality that trigger spawning,” Dr Jones explained. “A loss in natural synchronicity could ultimately affect the arrival of the gametes at the surface, which could affect the separation for each species, a process which prevents or reduces hybridization between closely-related species by spawning at slightly different times.

http://ars.els-cdn.com/content/image/1-s2.0-S0025326X15005251-gr1.jpg

Reproductive cycle of the broadcast spawning Acropora species with indicative timings based on the studies of Hayashibara et al. (1997), Okubo and Motokawa (2007), Okubo et al. (2008) and Ball et al. (2002).

In recognition of the sensitivity of the early life-cycle stages of corals, and their importance to the marine community, policy makers have attempted to protect coral spawning periods from sediments generated by dredging-related activities. Since 1993, dredging projects in Western Australia that are close to reefs are required to temporarily stop when corals are spawning five days before spawning and up to seven days afterwards.

This management approach has also been adopted in some dredging projects on the Great Barrier Reef and the possibility of introducing this practice to other locations such as Singapore has been suggested but it’s a contentious issue internationally because it can significantly inflate costs.

One of the most contested issues is the length of the window and also whether dredging-related turbidity-generating activities need to cease entirely or whether dredging can continue but must adhere to more conservative water quality guidelines.

Sperm tangled in sediment particles. WAMSI scientists are examining whether this impacts on the reproductive success of corals (Image: AIMS)

“The successful use of a coral spawning environmental window as a management tool depends on a shutdown period which encompasses the entire period that turbidity-generating activities could have an effect on spawning and ultimately the successful recruitment of juveniles into the next generation,” Dr Ross Jones said. “The window needs to contain sensitive stages such as settlement and early post-settlement survival.”

In Western Australia there is a well-known main autumn spawning period, but more recently a significant spring spawning period has been identified.

“The presently applied 12 days coral spawning shutdown period is too short to fully encompass the full settlement period, especially settlement and early post-settlement survival,” Dr Jones said.

“Extending the window before and after the predicted spawning date seems an obvious next step to also accommodate effects on gametogenic and spawning synchrony and to fully cover the settlement period. This may however significantly limit time that turbidity-generating activities could occur near coral reefs in any given year.

“Although the approach seems logical, the question is whether this approach is reasonably practicable and whether the resulting intermittent and protracted dredging operation would result in a better net environmental benefit than a shorter campaign.

“What we do know is that conducting dredging activities at a time that avoids coral spawning periods and settlement periods constitutes a best management practice,” Dr Jones said

[R. Jones,,G.F. Ricardo,,A.P. Negri, (2015) Effects of sediments on the reproductive cycle of corals. Marine Pollution Bulletin doi:10.1016/j.marpolbul.2015.08.021]

This project was funded by the Western Australian Marine Science Institution as part of the WAMSI Dredging Science Node, and made possible through investment from Chevron Australia, Woodside Energy Limited, BHP Billiton as environmental offsets, and by co-investment from the WAMSI Joint Venture partners. This research was also enabled by data and information provided by Chevron Australia. The commercial investors and data providers had no role in the data analysis, data interpretation, the decision to publish or in the preparation of the manuscript.

Category:

Dredging Science

New master plan for Swan and Canning rivers

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Perth’s much-loved Swan and Canning rivers will remain vibrant and accessible for all West Australians under a new State Government strategy released today (Tuesday 20 October).

Environment Minister Albert Jacob said the Swan Canning River Protection Strategy provided a master plan to guide investment, keep the rivers healthy and ensure they were accessible for the community to enjoy in the long term.

“For the first time, we have a whole-of-Government strategy that sets out a shared vision on what needs to be done to make sure our rivers are better protected while meeting the demands of a growing city,” Mr Jacob said.

“This strategy will better co-ordinate work between the government agencies involved in managing the rivers with the aim of improving benefits to the community and ensuring the rivers continue to be attractive and desirable places.

“This improved integration between agencies will lead to more efficient use of the State Government’s substantial investment in the management of our rivers with better outcomes for river health and community use and enjoyment.”

Read more…

 

 

Category: 

Estuary Science

Premier briefed on Kimberley marine research projects

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WA Premier and Science Minister Colin Barnett released two AFL celebrity into waters off Broome as part of a broader program of marine research in the Kimberley.

The two green sea turtles Cyril and Sharrod, named after the AFL Hawkes forward Cyril Rioli and Eagles defender Sharrod Wellingham by the Yawuru Rangers, were caught in the waters off Roebuck Bay and tagged with a satellite tracking device. Premier Barnett released the turtles as part of the Yawuru Rangers marine turtle monitoring collaboration. The results will be updated daily on seaturtle.org.

Premier Barnett was also briefed on the Kimberley Marine Research Program by WAMSI program leader Stuart Field (DPaW); a $30million project under WA’s Kimberley Science and Conservation Strategy with 10 partner agencies and more than 100 scientists delivering 26 projects.

Researcher Scott Whiting prepares a turtle for release (Photo: Stuart Field, DPaW)
Tagged and ready for release
(Photo: Stuart Field, DPaW)

 

Premier Colin Barnett releasing Cyril the green sea turtle (@CollinBarnett: Twitter)
Monitor Cyril’s and Sharrod’s progress on seaturtle.org.

The Premier and Yawuru Rangers watch the sea turtles’ progress (DPaW)

 

WAMSI-DPaW Stuart Field briefs Premier Colin Barnett on WAMSI marine research in the Kimberley (DPaW)

FACT FILE:

DPaW Yawuru Rangers sea turtle monitoring:

  • Three species of marine turtle are common residents in Roebuck Bay (Green, hawksbill and flatback turtle), with other species (loggerhead, leatherback) less common.
  • Green turtles are abundant in Roebuck Bay and are ecologically and culturally significant.
  • Green turtles are a primary consumer of seagrass and algae and play a major role in the health of these systems.
  • Green turtles are highly significant in Yawuru culture and are important for food, ceremony, stories and songs.

Results from this study will provide information on:

  • Spatial (where) and temporal use (when) of habitats;
  • What habitats are important and how they use them;
  • How they use the proposed Roebuck Bay Marine Park and areas outside the park;
  • Identify any other spatial areas that are important (for example – are they frequently visiting areas 100 km away):
  • Identify areas where turtles and human pressures overlap (eg shipping lanes);
  • The results will be updated daily on seaturtle.org.
Category:

Kimberley Marine Research Program

Ancient building rite marks milestone for new collaborative research centre

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Published in AIMS Waypoint Spring 2015 Newsletter

 

An ancient ‘topping off’ ceremony was used in July to celebrate the successful installation of the final concrete beam in the new Indian Ocean Marine Centre in Perth.

The new marine centre is on the University of Western Australia’s (UWA) Crawley campus, and marks an exciting time for new collaborative partnerships in marine science. The ceremony was held with AIMS, CSIRO, UWA and Western Australian Department of Fisheries researchers and staff.

Dr John Chappell, AIMS’ Operations and Infrastructure Manager, said, “It’s exciting to reach this significant milestone in constructing the new state-of-the-art facility that will bring together the Indian Ocean’s leading marine research organisations.”

Northwest Australian marine waters will never be the same: researchers will focus on discovering, understanding and monitoring those tropical waters, and in doing so, supporting the protection and sustainability of our ocean heritage.

More than fifty guests watched UWA Chief Operating Officer, Gaye McMath, lead the topping out of the $60.6 million building.

Grateful for the success of the project to date, Ms McMath expressed excitement about expanded research opportunities because of the collaboration of partners the centre would enable. “It will continue to build Australia’s international marine research status.”

Symbolising growth and bringing luck, a bouquet of plants from the UWA campus was also hung from the top of the building.

It’s expected the building will be finished in mid-2016, and will then house more than 330 multi-disciplinary researchers specialising in fisheries, marine technology, marine ecology, geochemistry, governance and engineering.

The Indian Ocean Centre was enabled by contributions from the collaborating organisations and a $34 million grant from the Australian Government, highlighting the wide commitment to premiere tropical marine research.

Also celebrating were people from site contractor BGC Construction. Their work has brought together essential services within the six-storey building with sustainable design principles.

Signals from the sawfish nursery

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By Jeff Whitty and Dr David Morgan

Murdoch University’s Freshwater Fish Group (Centre for Fish & Fisheries Research) in conjunction with the Nyikina-Mangala Rangers, are unravelling the mysteries of one of the most threatened fishes in the world, the freshwater sawfish (Pristis pristis).

A WAMSI project funded by Chevron Australia, ‘Team Sawfish’ is helping to protect one of the world’s largest fishes that is found in freshwater. The freshwater sawfish has declined globally, and in Australia is listed as Vulnerable on the Environment Protection and Biodiversity Conservation (EPBC) Act.

Facing multiple threats including fishing pressure, often by means of bycatch and habitat modification, the numbers and ranges of all sawfishes have greatly declined. In Western Australia, the freshwater sawfish inhabits rivers as juveniles and as such it is likely to be impacted by habitat modifications such as instream barriers (e.g. dams), which may obstruct their migrations into freshwater nurseries. Murdoch University researchers are investigating what impacts these barriers may have on the freshwater sawfish.

In August 2015, Team Sawfish, consisting of Murdoch University researchers and the local Nyikina-Mangala Rangers, set out to continue their work studying the impacts of such barriers in the Fitzroy River, Western Australia.
Team Sawfish measuring a freshwater sawfish

Starting at 360rkm (i.e. 360 kilometres upstream of the river mouth), Team Sawfish systematically sampled pools for sawfish as they moved downstream, including those pools located in close proximity to  the various barriers on the river and ending within the estuarine pools near the river mouth.

The aim of this trip was to catch and tag freshwater sawfish with acoustic transmitters in order to monitor and thus better understand how anthropogenic barriers may affect the movements and/or behaviour of these fishes during the wet and dry seasons, noting movement over the barriers is only possible during peak flows during the wet season (December-April).
Nyikina-Mangala Rangers preparing to deploy an acoustic receiver to monitor the movements of tagged sawfish

During their sampling efforts, Team Sawfish found pools along the river to have become filled in and shallow, a likely result of the lack of flushing of introduced sediments during the past few small wet seasons.

The small 2014-2015 wet season also seemed to have led to the capture/presence of very few sawfish and no young of the year (those pupped within the 2014-2015 wet season).

This finding was congruent with findings from previous years, which suggested that the relative abundance of sawfish within the freshwater pools of the river is positively correlated with the size of the previous wet season.  

The Freshwater Sawfish that were captured were limited to size classes that would have been pupped in 2011-2012. Observing sawfish from the 2011 year class to still be present within the river provided further evidence that some juvenile sawfish do inhabit the river for more than four years, as previous data suggested.

The monitoring of sawfish continues and the team is continuing to tag and record freshwater sawfish in spring of this year.

If you catch a tagged sawfish, or would like to know more about these mysterious creatures, please contact fish@murdoch.edu.au.

 

Category: 

Sawfish Project

IGEM collaboration important first step in voluntary industry data sharing

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The success of a pilot project that generated a snapshot of environmental data relevant to impact assessment and monitoring off the northwest coast is on track to begin sharing industry meta-data from the many industry funded studies in Western Australia.

Several conscientious oil and gas companies have taken the initiative by agreeing to share information about the huge number of datasets they collect.

Woodside, Chevron, Inpex, Murphy Oil Australia, PTTEP, Quadrant Energy (formally Apache), Santos, Shell Australia, facilitated by their peak industry body APPEA, are creating a meta-database called the Industry-Government Environmental Meta-database (IGEM), which is being developed and operated by the Western Australian Marine Science Institution (WAMSI).   

Metadata is information about data. It tells you where, how, when and what data was collected.  As well as these companies, WAMSI, the Australian Institute of Marine Science and the state government Departments of Parks and Wildlife, and Fisheries are also contributing their own metadata to the IGEM.

“As an industry, we collect a huge amount of data,” Chair of the APPEA Environment and Safety Committee Gerry Flaherty said. “But right now only the companies who pay for the projects know what has been collected.  If we have an emergency we need to respond to quickly. Having a place where everyone can see what information is out there will dramatically improve our response.”

“This will be a great advantage for IGEM partners in projects to inform regulatory processes or for research purposes, not just response,” WAMSI CEO Patrick Seares said. “It means they can look at the IGEM to see what already exists, then negotiate access to it with the owners rather than doing expensive duplicate fieldwork.”

IGEM will have the capacity to increase its key datasets but it will begin with using metadata collected post-2008 in seven key areas: mangroves; benthic habitats; demersal fish, nesting turtles, seabirds and shorebirds, megafauna; and sediment quality.

Subscribers will be able to search for relevant environmental studies by research activity in a specific area; the date it was collected; the organisation that collected the data; type of data; and key words.

The in-development web-based platform should initially provide access to geospatial metadata records on key studies off Western Australia, but with the potential to expand nationally. The site will have a page accessible to the general public with limited information and a log-in interface for approved members who can generate reports.

“I hope as we can start seeing the system evolve that other companies, agencies and research groups see the positives in this process and follow the lead of the current participants,” Patrick Seares said. “Sharing metadata has so many upsides and really doesn’t expose the data owners to any risk.”

The IGEM platform is expected to be available by early 2016.

Field report from research vessels in Camden Sound, Kimberley region

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The initial ship-based expedition to Camden Sound was conducted under the auspices of WAMSI’s Kimberley Benthic Biodiversity Project, which aims to provide a better knowledge base about what occurs where in the Kimberley’s diverse marine environments, especially in areas of management priority such as the state government’s proposed marine parks and reserves.

Cruise leader on board the RV Solander, Dr Andrew Heyward from AIMS in Perth, said that the vessel operated 24/7 during its 18-day itinerary. “Scientists and staff worked in shifts, doing towed video and sediment sampling during daylight, and multibeam sonar surveys during the night,” he said.

Although the weather was generally very good, extreme tides, strong currents, turbid waters and some uncharted areas provided plenty of challenges for researchers. They successfully completed more than 200 km of towed video and thousands of km of multibeam seafloor mapping, in the first of two expeditions to the Camden Sound area.

“We’ve seen large areas of dynamic sand across the open Sound, including some patches with underwater sand dunes,” commented Andrew, “but also rocky ground covered in a large variety of marine invertebrates, in particular sponges and soft corals.”

The turbid waters of Camden Sound prevent sunlight from penetrating more than ~10 m in depth, so organisms that need light – such as corals and seaweeds – appear to be restricted to the shallowest parts of rocky ground and the upper edges of fringing reefs around islands. As depth increases and light fades the filter feeding sponges, soft corals, ascidians and bryozoans become the dominant components of the seabed communities.

“Thanks to the combined efforts of the Solander and the Linnaeus this month,” said Andrew, “we’re beginning to understand a lot more about what the seafloor of the Lalang-garram-Camden Sound Marine Reserve looks like, and the benthic biodiversity that lives there.”

Dr Iain Parnum from Curtin University is busily compiling all the gathered multibeam sonar data now. “In terms of outputs, first of all, we’ll deliver some much-needed improved bathymetry information for Camden Sound,” he explained. “Secondly, sonar backscatter data – both from the seafloor and the water column – will give us good insights into the kinds of underwater terrain and ecosystems at each sampled location.”

In addition, Dr John Keesing from CSIRO took advantage of the presence of the RV Solander in the Kimberley to advance another WAMSI project investigating historic changes in water quality. He collected sediment cores (each ~1.5 m long) at ~20 m depth from two locations in Roebuck Bay. “These cores will be used to reconstruct a time series of water quality in the Bay, which is expected to go back about 100 years,” he said.

As with all WAMSI projects, the data and outputs will be freely available to everyone with an interest in the marine environments of the Kimberley.

Map showing sites in Camden Sound where towed video surveys were conducted in November 2014 

 

A still image from one of the towed video surveys showing mixed filter-feeding community (including bryozoans, sponges and soft corals) growing on a rock outcrop (Photo courtesy of AIMS)

Category:

Kimberley Marine Research Program

Vale Professor Lindsay Collins

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We are deeply saddened to hear of the passing of Professor Lindsay Collins.

Lindsay has been involved with WAMSI since its inception in 2006. A leading geomorphologist with the Applied Sedimentology and Marine Geoscience Group, Department of Geology at Curtin University, he was a valued friend and project leader on both the Ningaloo Research Program in collaboration with CSIRO and the WA Museum, WAMSI’s Caring for our Country Project – Shark Bay and the current Kimberley Marine Research Program.

Lindsay was one of life’s true gentlemen and we all owe him a debt of gratitude for his dedication and lasting contribution to marine science.

He shared his passion for geomorphology supervising some 50 Honours, Masters and PhD geoscience students over his more than 40 years of research and teaching during which time he earned the respect of his colleagues as a highly cited scientist and an expert in his field.

Lindsay Collins could always be relied on to produce high quality, successful and valuable collaborative projects. Just this year we were fortunate to have him present his latest project for us on Kimberley Reef Growth and Maintenance at the WAMSI Conference in March.

Lindsay’s wise guidance about science, but also people, has always been highly valued by WAMSI. His engaging personality and honest opinion were a great asset to the marine science community as a whole.

On behalf of all of us at the Western Australian Marine Science Institution and its partners I offer our sincere condolences to his family, and his many colleagues.

Patrick Seares
WAMSI CEO
 

The funeral for Professor Lindsay Collins will take place next Friday, 11th September at 2.30 at Karrakatta Cemetery, followed by a wake at Cottesloe Beach Hotel at 4.30pm.

Lindsay Collins and Premier Colin Barnett at the 2015 WAMSI Conference

 

Kimberley crocodile numbers triple in biggest survey in three decades

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Early results from WAMSI’s crocodile survey in Western Australia’s north suggest their numbers have tripled over the last 30 years.

(More…)

(Video: Croc Watch: ABC Landline)

Category:

Kimberley Marine Research Program

Re-defining sediment transport models over coral reefs and seagrass meadows

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Novel research within WAMSI’s Dredging Science Node will redefine how current dredged sediment transport models predict key pressure parameters such as sediment deposition rates within ecologically significant marine habitats.

Sediment deposition and subsequent smothering of marine habitats such as corals and seagrasses is one of the mechanisms by which dredging can impact on the environment.

However, according to Professor Ryan Lowe from The University of Western Australia, current sediment transport models are severely lacking in their ability to predict rates of sediment deposition and re-suspension over coral reefs and seagrass meadows with any degree of confidence.

Canopies formed by seagrass meadows impose drag forces that can trap sediment. This is not accounted for in sediment transport models.

“The first step in the Environmental Impact Assessment (EIA) process for proponents of new developments is to make predictions on the likely extent, severity and duration of their impacts on the environment,” Professor Lowe said. “To do this for projects involving dredging, proponents use sediment transport models that make predictions of where dredge plumes will go and what impacts they will have when they get there.”

“Current sediment transport models assume that the seafloor is essentially flat and that nothing is growing on it. However, in reality the large roughness, or canopies, formed by coral reefs, seagrass meadows and sponge gardens impose substantial drag forces that will alter turbulent flow structure over very small spatial scales and can trap sediment. As a consequence, current sediment transport models can grossly underestimate the rates of sediment deposition that occur in and around these important habitats.”

Sawhorse instrument frame deployed at Ningaloo Reef with hydrodynamic and sediment transport instrumentation. Photo: Andrew Pomeroy

Professor Lowe and UWA collaborator Dr. Marco Ghisalberti are leading a research program combining field and laboratory techniques to address this problem.

“In the field we are measuring turbulent flow structure and sediment concentrations above and within the coral reef and seagrass meadow canopies,” Professor Lowe said. “These direct measurements are compared with various conventional sediment transport models and highlight the major deficiencies.

“We are also conducting parallel and complementary laboratory experiments. The advantage of laboratory experiments is that we can examine in detail the mechanisms and processes in a controlled setting. We can control the densities and heights of canopies, and factors like whether they are completely submerged or not. In this way we can precisely measure transport rates, near bed turbulence, sheer stress and look at the effect of canopies on transport rates and subsequent deposition,” he explained.

Laboratory experiments of sediment transport through artificial canopies

The ultimate goal of this research is to develop new and improved transport formulations and algorithms that can more accurately predict rates of sediment deposition and the subsequent impacts to seabed communities.

“If we can achieve this, then both the Environmental Protection Authority and project proponents will have greater levels of confidence in the prediction of impacts during the EIA process,” Professor Lowe said. “And this is what the Dredging Science Node is all about.”

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