Background Information

Gathering information on marine climate impacts.

Australia’s climate and prosperity is strongly connected to the oceans; we are highly sensitive to an ocean influenced climate, extract huge economic benefit from our ocean territory, are custodians of marine biodiversity of globally significant conservation value, and have a highly urbanised population living on or near the coast.

Katy Hill 1, Boris A. Kelly-Gerreyn 2, Rick Stuart Smith 3, Karen Evans 4, Keith Hayes 5.

1 Integrated Marine Observing System, University of Tasmania, Hobart.
2 The Australian Bureau of Meteorology, Melbourne.
3 Institute of Marine and Antarctic Studies, University of Tasmania, Hobart.
4 National Wealth from Oceans Flagship, CSIRO Marine and Atmospheric Research, Hobart.
5 NERP Marine Biodiversity Hub, CSIRO Marine and Atmospheric Research, Hobart.

Despite a modest population, Australia has the 3rd largest ocean territory on the planet, and is a key Southern Hemisphere partner on the global effort to monitor the oceans. Sustained, routine observations of the oceans over multiple decades are needed to be able to understand climate change impacts in the context of climate variability. Processes which drive variability in the oceans operate on timescales from intra-seasonal (e.g. storm driven upwelling) to decades (Pacific Decadal Oscillation), and the response of the ecosystem can occur at a range of levels from phytoplankton through to large apex predators (large fishes such as tuna and sharks and mammals such as seals and whales).

Historical Observations

Historically, routine observations of the oceans around Australia are sparse. The CSIRO has sustained roughly monthly observations of temperature, salinity and nutrients at three coastal stations since the 1940s and 1950s; these are at Maria Island, Tasmania; Port Hacking, New South Wales; and Rottnest Island, Western Australia. Data from Maria and Rottnest have provided insights into low frequency variability in and changes in the East Australian Current (EAC) and the Leeuwin Current (Pearce and Feng 2007; Ridgway et al. 2007; Hill et al. 2008) and associated influences on marine ecosystems (Harris et al. 1987, Johnson et al., 2011). These stations are being sustained and expanded as part of the Integrated Marine Observing System (IMOS) network of National Reference Stations (see below Sustained Ocean Observations).

Australia also contributes to the sustained observing system through its contributions to the Global Ocean Observing System (GOOS). Key contributions include:

- Expendable Bathythermographs (XBTs) have been deployed from ships of opportunity along repeat sections since the late 1980s, established as part of the international Tropical Oceans Global Atmospheres (TOGA) experiment (Webster and Lukas 1992). XBTs deliver temperature profiles down to 800m along common shipping routes. Sections are generally high resolution (eddy resolving) and/or frequently repeated (monthly occupied). The high resolution XBT lines cross key boundary currents in the Australian region and XBT data have been used to determine the decadal variability in the EAC system (Ridgway et al. 2008; Hill et al. 2011a).

- Repeat hydrographic sections carried out by ships still provide the only complete full depth inventory of key ocean properties (heat, salt, carbon, nutrients and overturning circulation/watermass formation and fate) along transects repeated every 5-10 years; at this stage, biological observations are not included. The network of sections was set up during the international World Ocean Circulation Experiment (WOCE: http://www.nodc.noaa.gov/WOCE) and countries commit to occupying sections (now coordinated through the Global Ocean Shipboard Hydrographic Program, GO-SHIP: http://www.go-ship.org). Australia’s ability to contribute to the GO-SHIP Program will be vastly increased with the arrival of the new bluewater research vessel, the RV Investigator in 2013.

- The International Argo profiling float program (http://www.argo.net) delivers broad-scale temperature and salinity data of the global oceans down to 2000 metres. It was set up in 2000 with the aim of achieving one profiling float every 3 degrees. Australia is a key player in this program, particularly in the Southern Hemisphere (see details below in Sustained Ocean Observations).

- Satellite Remote sensing data provides global snapshots of the surface of the ocean, and is essential for understanding meso-scale variability of the ocean. A range of satellites have delivered global sea surface temperature, sea surface height, and ocean colour data streams since the 1980’s. Although Australia does not invest in satellite launches, it is a beneficiary of the resulting data products.



Figure 1: A map of the global sustained observing system, which was designed post the World Ocean Circulation Experiment in 1999.

Routine operational ocean observations to support weather, ocean and climate state and forecasting: The Bureau of Meteorology.

The Bureau of Meteorology (BOM) operates marine observing networks to provide data for day to day weather forecasting for the public and the marine user communities in Australia. The marine data are also distributed and used internationally as input to computer-based weather and ocean prediction systems, and support the seasonal scale climate prediction of events such as El Niño and La Niña in the Pacific. These data are also archived as a long-term record of how the world's climate is changing and feed into research activities. The Bureau is also an operator of components of the Integrated Marine Observing System (see below Sustained Ocean Observations). The Bureau's marine observing networks include:

- Sea Level: the Bureau operates and manages 42 sea level stations spread across the Australian coastline, the South Pacific and the eastern tropical Indian Ocean. The stations serve multiple purposes - tsunami monitoring, tide predictions, sea level change - and make up part of the Australian Tsunami Warning System.

- Drifting buoys: these are fully autonomous buoys deployed off merchant vessels used to measure surface currents, sea level pressure and sea surface temperature. The Bureau deploys approximately 25 drifting buoys each year as part of a global effort. These buoys are vital for validating satellite data and for use in numerical weather prediction and ocean forecasts.

- Wave buoys: a network of 32 wave platforms distributed around the Australian coastline is monitored. The data from the two buoys owned by the Bureau are quality controlled and made available for climatological studies and model development. The real-time data are used for the provision of marine weather services.

- Tsunameters: a network of six surface buoys anchored in deepwater and coupled to bottom acoustic transducers close to fault lines in Australian waters. These tsunameters provide continuous monitoring of tsunami threats, but can also be used to resolve tides. Some are also equipped with meteorological sensors and could be instrumented with other sensors (biological and chemical).

- Australian Voluntary Observing Fleet: the Bureau recruits up to 100 volunteer merchant vessels to report the weather at sea as part of a global network contributing to meteorological services and climate databases. The availability of ships changes frequently due to economic factors, but this form of data collection is unique in providing cost effective meteorological and climate relevant coverage over the marine environment.

Sustained Ocean Observations for research applications: The Integrated Marine Observing System (IMOS).

IMOS is a national, federally funded program for sustained observations of the ocean to support marine and climate research (http://www.imos.org.au; Hill et al. 2011b). With 10 major organisations (both agencies and universities) working together as a national community, a range of observing equipment has been deployed in the oceans around Australia. All of the data is freely and openly available through the IMOS Ocean Portal (http://imos.aodn.org.au).

Observations being undertaken are guided by science plans developed within the marine and climate science community. These plans address five major research themes: multi-decadal ocean change, climate variability and weather extremes, major boundary currents, continental shelf processes and biological responses. IMOS is designed to be a fully-integrated, national system, which aims to integrate from the open ocean onto the continental shelf and into the coast, and from physics through to biology. Given the timescales on which these marine and climate processes operate, IMOS needs to be sustained over decades to fulfil its potential.

IMOS operates as a matrix of Nodes and Facilities. The science Nodes act as a focal point for the scientific community and stakeholders to influence the design of the observing system by developing the science plans. There is a Bluewater and Climate Node, and five Regional Nodes around Australia.
Data-streams are delivered by ten facilities to meet the needs of the Node science and implementation plans.



Figure 2: a screenshot of data streams available through the IMOS Ocean Portal. Yellow symbols: ARGO profiling floats, Orange, blue and purple lines: Ships of opportunity program. See http://imos.aodn.org.au for further details.

IMOS draws on a suite of platform types to deliver data streams, which all contribute to deliver data streams on a range of spatial and temporal scales.

- Argo profiling floats
provide broad-scale (roughly every 3x3 degrees) temperature and salinity data down to 2000m in the global ocean. Additional biogeochemical sensors are currently being trialled and may provide additional data streams in the future The Australian contribution to Argo has been enhanced under IMOS, making Australia the second largest contributor (after the US) to this global initiative, and a key partner in the Southern Hemisphere.

- Ships of Opportunity Program (SOOP) are an effective way of taking broad-scale measurements around Australia’s coast; using research vessels, which generally provide broad-scale observations and commercial vessels such as tankers and ferries, which provide repeat transect data. They also provide the opportunity to take coincident measurements of physics, biogeochemistry and biology; with observations ranging from Air Sea fluxes and temperature profiles from Expendible bathythermographs (XBT’s) to plankton samples from continuous plankton recorders and bioacoustics (for Nekton biomass).

- Deepwater moorings are either deployed as single time-series moorings, or as part of arrays. The Southern Ocean Time Series is a suite of three multidisciplinary moorings in the Subantarctic zone south of Tasmania. Arrays of deep water moorings are used to measure mass, heat and salt fluxes across key currents circulation choke points such as the Indonesian Throughflow, East Australian Current and Antarctic Bottom Water formation on the Adelie coast of Antarctica.

- Ocean gliders are semi-autonomous platforms that deliver temperature, salinity and bio-optical data across boundary currents (deep diving Seagliders) and the continental shelf (shallower Slocum gliders).

- The Autonomous Underwater Vehicle surveys reference sites around the country, delivering stereo imagery of the benthic environment.

- The National Mooring Network is a combination nine multidisciplinary National Reference Stations (NRS) and shelf arrays designed to observe continental shelf processes such as shelf currents and upwellings.

- Ocean Radar delivers surface current maps as well as some information on wind and waves at six sites around the country.

- Animal Tagging provides observations of apex predator movements using acoustic telemetry, satellite telemetry, and archival data loggers. Acoustic tags are deployed on large fish such as sharks and tuna, and are recorded by acoustic listening stations deployed in curtains at various points around the Australian coastline. In the Southern Ocean, a combination of satellite tags and archival data loggers give information on movements of a range of animals from seals to seabirds. Satellite tags on seals also provide temperature and salinity data as they dive.

- Wireless Sensor Networks around island research stations on the Great Barrier Reef provide communications into which researchers can “plug and play” instruments for data to be delivered in real time.

- Satellite Remote Sensing sea surface temperature, sea surface height and ocean colour. IMOS collects in situ data to validate global products in our region and processes data to provide the best possible long time series of satellite products.

Using and reusing data: The Australian Ocean Data Network (AODN)


Taking ocean observations are expensive. Often observations which have been taken as part of a particular project could be used for multiple applications, if there was a mechanism for scientists to search for and access the data. Through IMOS a culture of data sharing, based on internationally agreed formats was promoted, and the IMOS Ocean Portal was established. The Australian Ocean Data Network is based on the IMOS data infrastructure, which has been expanded to house all kinds of marine science data. Six major federal agencies have signed up to making their marine data available through this system (the Australian Antarctic Division, the Australian Institute of Marine Sciences, the Australian Bureau of Meteorology, CSIRO, Geoscience Australia and the Royal Australian Navy). Efforts are also underway to work with State Agencies, Universities and the private sector in making data available.



Figure 3: A snap shot of the Australian Ocean Data Network portal, showing research vessel tracks and hydrographic station data.


Observing coastal waters


Australia’s coastal ecosystems are subjected to many pressures including sea level rise and storm surges, pollution, coastal development in addition to broader pressures such as temperature rise, ocean acidification and fishing pressures. Many organisations have an interest and take measurements in the coastal zone, including local, state and federal agencies. Ecological observations in particular, are typically made using different methodologies or to different standards in different areas and much of these data are not publically accessible. This makes national level coordination of coastal observations highly challenging.

As a first step towards increased coordination of coastal observations, IMOS and the Terrestrial Ecosystems Research Network (TERN, http://www.tern.org.au) are working together to ensure that the ocean observing system and the terrestrial observing system integrate in the coastal zone. IMOS is working with TERN and regional stakeholders to liberate data from the coastal zone into the AODN, so that it can be integrated and put in the context of broader observations available. TERN’s Australian Coastal Ecosystems Facility is investing in coastal bathymetry, coastal ocean colour, beach morphology and a sea turtle database.



Figure 4: A zoom in on some of the data available in the Great Barrier Reef region.

Observations of ecosystem impacts.


Comprehensive, routine measurements of ecosystems present a challenge as coincident observations cannot be made at all trophic levels, on all spatial and temporal scales. Among the few long-term ecological observation programs that exist in Australia, very few exceed a local, or at most, regional scale. Research is still required to determine what priority observations are needed to understand changes and variability in the ecosystem. Identifying key ecosystem health indicators will be important, for example in assessing the effectiveness of Marine Protective Areas (MPAs) and ensuring sustainable use of resources.

IMOS is currently engaged with the National Environmental Research Plan (NERP) biodiversity hub to identify observation systems and data streams in Commonwealth waters that are relevant to the federal government’s marine bioregional planning and ecosystem health initiatives. The Commonwealth governments’ Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC) has identified over thirty Key Ecological Features (KEFs) in Australia’s Commonwealth waters. The KEFs reflect biodiversity and productivity values and form the centrepiece of the department’s initiatives to identify indicators of ecosystem health, and to monitor and report on changes and trends in these indicators.

Pressures identified for bioregion KEFs include climate-change induced changes in ocean acidification, temperature, boundary currents and upwellings. IMOS and the NERP biodiversity hub are currently assessing observation platforms that are located in KEFs with the aim of identifying data streams that can be used to validate predictions about how the ecological indicators drawn for the physical and biological components of KEFs will respond to these pressures. It is anticipated that IMOS and the AODN will become an important component of a national monitoring evaluation and reporting scheme that will help inform Commonwealth government’s response and adaptation to climate change impacts in the marine environment.

Under the auspices of the Reef Life Survey Foundation (RLS), a national network of researchers, managers and recreational divers have recently established a large-scale ecological observation network for inshore waters around Australia (and offshore islands and reef systems. See Edgar and Stuart-Smith 2009; Edgar et al. 2009 for examples of data applications). The RLS dataset currently covers densities of fishes and mobile invertebrates at >1,100 sites spanning the continent – including temperate and tropical domains and all major coastlines. Over 50,000 photographic images of the substrate have also been taken at the same set of sites, providing a permanent archive of habitat characteristics and allowing quantification of change in the percentage cover of coral, macroalgae and other taxa. The RLS dataset continues to expand through time; with annual monitoring undertaken at core locations distributed around the country, and also a rapidly-growing coverage worldwide. Long-term continuation of the RLS network will provide invaluable insights into climate-related trends in marine biodiversity, including interactions between climate and pollution, fishing and introduced species on reef ecosystems, at local, national and global scales.



Figure 5. Map of sites surveyed by Reef Life Survey divers around Australia, 2008-2011 (red = priority sites).

The Australian Fisheries Management Authority (AFMA) maintains and co-ordinates a scientific observer program which collects information on both target and non-target species and associated fishing operations across all fisheries operating in Commonwealth waters. Initiated in 2001, the requirements and priorities for the observer program for each fishery are determined by relevant stakeholders, which include the fishing industry, government agencies and research institutions. The observer program also supports the collection and maintenance of observations of key species (particularly those of conservation concern) that interact with fisheries within the region to support conservation and management measures developed by AFMA for Commonwealth fisheries and those adopted by Australia under regional fisheries management organisations such as the Western and Central Pacific Fisheries Commission and the Indian Ocean Tuna Commission. Data from this program are utilised by numerous research programs conducted by national and international research agencies and universities and as the time series of data collected expands will provide invaluable insights into climate-related trends in marine biodiversity (e.g. Allain et al. 2012).

Observing and modelling the ocean

Despite efforts such as those described above, even the most developed observing system will always provide limited coverage, both in time and space. To garner full benefit from ocean observations observing systems need to be optimally designed and work hand in hand with numerical models to benefit the development and applications of both. Observations can be assimilated into models to provide the best estimate of the state of the ocean and how it has evolved in the recent past and to help initialise ocean forecasts. Models are used to inform the design of the observing system by identifying regions of large errors in the model, understanding the spatial and temporal scales of variability in the ocean, or for observing system design. Ocean Model data was used to support the design of the East Australian Current mooring array to ensure it captured the full cross section of the current, including variations in its path.

Gaps, challenges and future priorities

The Marine Climate Impact Report Cards demonstrate that there is a need for Australia to not only maintains, but enhance its capability and capacity to develop, deploy and evaluate marine observing systems into the future. While we have achieved a step change in our ability to observe the ocean, particularly in the last decade, there are gaps and challenges to address as we continue to maintain those observation systems into the future. The deep ocean remains largely un-observed below 2000m, yet stores much of the heat and carbon in the global system. There are also few routine observations of the cryosphere, and notably seasonal sea-ice systems, which are known to have a fundamental role in the climate system including deep ocean circulation. These regions also contain some of the more seasonally productive regions of the global oceans, attracting large aggregations of apex predators.

The priorities and requirements for an observing system to monitor the open ocean physics is well established nationally and internationally through the development of systems such as the Global Ocean Observing System (GOOS: http://www.ioc-goos.org). Achieving similar monitoring standards for coastal waters, marine ecosystems is more challenging. A wider range of parameters is needed and their use are also broader in their aims and focus. Additionally, there is less international consensus on requirements for an ecosystem observing system and a lack of technology for widespread automated ecosystem observations. Efforts are underway to develop coherent priorities for ecosystem monitoring nationally (through IMOS and the Marine Biodiversity Hub) and internationally (through the expansion of the GOOS remit).


Acknowledgements

IMOS is supported by the Australian Government through the National Collaborative Research Infrastructure Strategy and the Super Science Initiative. It is led by the University of Tasmania on behalf of the Australian marine & climate science community and IMOS infrastructure is operated by the following institutions:



More information on observing programs:

The Bureau of Meteorology http://www.bom.gov.au
The Integrated Marine Observing System http://www.imos.org.au
Reef Life Survey http://www.reeflifesurvey.com
Redmap http://www.redmap.org.au
The Terrestrial Ecosystem Research Network http://www.tern.org.au

Allain, V., S. Nicol, J. Polovina, M. Coll, R. Olsen, S. Griffiths, J. Dambacher, J. Young, J. Molina, S. Hoyle, T. Lawson, (2012). International workshop on opportunities for ecosystem approaches to fisheries management in the Pacific Ocean tuna fisheries. Reviews in Fish Biology and Fisheries, 2012, Volume 22, Number 1, Pages 29-33 Edgar, G.J, N.S. Barrett and R.D. Stuart-Smith (2009). Exploited reefs protected from fishing transform over decades into conservation features otherwise absent from seascapes. Ecological Applications, 19, 1967-1974. Edgar, G.J and R.D. Stuart-Smith (2009). A continental-scale analysis of ecological effects of marine protected areas based on underwater visual surveys. Marine Ecology Progress Series, 388, 51-62. Harris, G., C. Nilsson, L. Clementson and D. Thomas (1987). The water masses of the east coast of Tasmania: Seasonal and interannual variability and the influence on phytoplankton biomass and productivity Australian Journal of Marine and Freshwater Research 38(5) 569 - 590 Hill, K.L, S.R. Rintoul, K.R. Ridgway and P.R. Oke (2011a) Decadal changes in the South Pacific Western Boundary Current system revealed in observations and ocean state estimates. Journal of Geophysical Research, 116, C01009, doi:10.1029/2009JC005926. Hill, K.L., T. Moltmann, R. Proctor, S. Allen (2011b) The Australian Integrated Marine Observing System: Delivering data-streams to address national and international research priorities. Marine Technology Society: US-IOOS Special Issue, 44, 65-72. Hill, K. L., S. R. Rintoul, R. Coleman, and K. R. Ridgway (2008). Wind forced low frequency variability of the East Australia Current, Geophysical Research Letters, 35, L08602, doi:10.1029/2007GL032912. Johnson, C.R., S. C. Banks, N.S. Barrett, F. Cazzasus, P.K. Dunstan, G.J. Edgar, S.D. Frisher, C. Gardner, F. Helidoniotis, K.L. Hill, N.J. Holbrook, G.W. Hosie, P.R. Last, S.D. Ling, J. Melbourne-Thomas, K. Miller, G.T. Pecl, A.J. Richardson, K.R. Ridgway, S.R. Rintoul, D.A. Ritz, D.J. Ross, D.C. Sanderson, S. Shepherd, A. Slotwinski, K.M. Swadling, N. Taw (2011). Climate Change cascades: shifts in oceanography, species ranges and marine community dynamics in eastern Tasmania. Journal of Experimental Marine Biology and Ecology. DOI: 10.1016/j.jembe.2011.02.032. Pearce, A and M. Feng (2007) Observations of warming on the Western Australian continental shelf. Marine and Freshwater Research, 58, 914-920. Ridgway, K.R., R.C. Coleman, R.J. Bailey and P. Sutton (2008) Decadal variability of East Australian Current transport inferred from repeated high-density XBT transects, a CTD survey and satellite altimetry. Journal of Geophysical Research, 113, C08039, doi:10.1029/2007JC004664. Webster, P. J. and Lukas, R. (1992) TOGA COARE: The Coupled Ocean-Atmosphere Response Experiment. Bulletin of the American Meteorological Society, 73: 1377-1416.
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