The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressure of Climate and System Variability". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Pressure – Climate and System Variability" DESCRIPTION OF PRESSURE Climate and the marine environment vary on multiple temporal and spatial scales. This variability results in seasonal, inter-annual, decadal and longer changes to water temperature (e.g. Figure 1), rainfall patterns affecting ocean salinity, and surface winds, oceanic currents and tidal regimes which can influence the degree of vertical mixing through the water column. Collectively, these changes also propagate from the physical environment up the food chain. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports on climate variability. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: High impact Assessment trend: Deteriorating Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Comparable • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Not previously assessed • 2011 • N/A CHANGES SINCE 2016 SOE ASSESSMENT The assessed state and trend of this pressure has increased from low/stable in 2016 to high/increasing for 2021 based on research documenting a trend for overall higher extremes of impacts associated with climate variability over the reporting period that is expected to continue.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - oceanic dissolved oxygen and oxygen minimum zones in shelf and offshore regions". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Surface ocean salinity is largely reflective of the exchange of freshwater with the atmosphere, with areas of high surface salinity found in regions where evaporation exceeds precipitation. Subduction of water from the ocean surface to the oceans interior transports surface salinity, resulting in salinity distributions of the oceans interior also reflecting surface rates of evaporation and precipitation. Melting and freezing of sea ice and glaciers also contributes to ocean salinity. Changes to salinity that may be driven by climate change have the potential to affect ocean circulation and stratification and contribute to sea level change. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports on ocean salinity and climate change. Details of the specific data sets used to generate this assessment have not been provided. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Deteriorating Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Grade and trend are not comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Ocean salinity was assessed under state and trends of physical and chemical processes and discussed in the text in terms of the pressure climate change.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Management Effectiveness of Climate and system variability and climate change". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Climate and system variability and climate change" BACKGROUND Climate variability, extremes and change affect Australia’s oceans, ecosystems and users of marine ecosystem services, with impacts that include changes in species distribution and abundance, disease outbreaks (e.g. corals, shellfish), and shifts in community composition. Managers of these marine ecosystem services variously respond to short and long-term impacts on a range of temporal and spatial scales. This assessment reports on the effectiveness of regional and local management responses to short-term climate variability, including extreme events, and long-term anthropogenic climate change impacts in Australia’s oceans. Increasing frequency and/or intensity of extreme events (e.g. cyclones and storm surge, marine heatwaves (flood plumes covered in Coasts chapter)), and long-term change in winds, ocean temperatures and pH (sea level is covered in Coasts chapter), can only be directly managed by global-scale emission reduction, carbon sequestration, and other climate system manipulations (geoengineering). The effectiveness of management of these manipulations is not covered in this assessment (e.g. Brent et al 2018, McDonald et al. 2019; McDonald et al. 2020; Gattuso et al 2021 for more information). DESCRIPTION OF THE APPROACH TO MANAGING THE PRESSURE Reactive and proactive management in response to climate pressures is influenced by the “agility” and risk appetite of the particular marine sector (Hodgkinson et al. 2014). Agility in both extractive (e.g. fishing, aquaculture, energy) and non-extractive (e.g. biodiversity, tourism) marine sectors is influenced by a range of factors related to innovation capacity (Figure 1). These are (1) degree to which system manipulation is possible (e.g. aquaculture vs wild fisheries), which can be related to the life cycle of the biological components (e.g. short-lived) or accessibility for manipulation (e.g. Alderman and Hobday 2017) and any associated infrastructure (moveable, restricted, flexible), (2) the regulatory environment (e.g. how flexible are management rules (Marshall et al. 2013)), (3) market forces (e.g. tourism season, consumer preference, competition), (4) value/profitability and relative size of marine industries, (5), leadership and key influencer attitudes, including political power and influence, (6) social expectations (e.g. expected to manage coral reefs, world heritage areas), and (7) visibility of impacts from extreme events or long term change (e.g. De’ath et al. 2012; Babcock et al. 2019). Currently most management responses are reactive (after an event) or implemented in real-time based on in situ or synoptic information. Proactive management, defined as forward planning ahead of an impact, can be informed by short-term forecasts and/or long-term climate projections (e.g. IPCC reports). Short-term forecasting approaches include using climatological patterns (i.e. manage conservatively using long term averages), analogue approaches (e.g. manage based on recent experience of an event), or dynamical forecasts (e.g. Hobday et al. 2018). Advance warnings at a range of time scales allows marine managers to implement strategies to minimise impacts of change. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports on climate variability. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • Approach • Assessment grade: Partially effective Assessment trend: Improving Confidence grade: Adequate Confidence trend:

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - nutrient supply and cycling". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Macronutrient concentrations (e.g. nitrate and phosphate) in the surface ocean play an important role in controlling the ocean’s primary productivity. The oceans account for about half of the earth’s total primary productivity. Surface ocean waters around Australia typically have low macronutrient concentrations for nitrate and phosphate. The key physical processes supplying nutrients to the upper ocean are the seasonal deepening of the ocean surface mixed layer, the upwelling and vertical mixing associated with ocean eddies, and wind-driven coastal upwelling. In the Australian region, the first two processes dominate because conditions that cause wind-induced upwelling are confined to a few regions (e.g. Bonney upwelling off South Australia). As the ocean warms around Australia (Lenton et al, 2015) the upper ocean will become more stratified and the vertical supply of nutrients to the surface ocean could decline (Bopp et al, 2013) reducing primary productivity. However, increased eddy activity due to strengthening of the East Australian Current may compensate for a decline in the vertical nutrient supply in the Tasman Sea and cause an increase in primary productivity with climate change (Matear et al., 2013). DATA STREAM(S) USED IN EXPERT ASSESSMENT Offshore data from around Australia from the latest CARS compilation (CARS2009a v1.1, as of 12 July 2010). See http://www.marine.csiro.au/atlas/ 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: High impact Assessment trend: Unclear Confidence grade: Evidence and consensus too low to make an assessment Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend not comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Unclear what data were used in the 2011 assessment; the 2016 assessment is based on the latest CARS compilations and so includes observations added to CARS 2011-2016.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with traditional use of marine resources". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Quantifying the traditional use of marine resources by Indigenous communities is difficult due to the dispersed and sporadic nature of much traditional harvesting and the often complex and sensitive process of building community endorsement for long term monitoring programs to quantify harvest levels. Across Australia, there is a high diversity of community initiatives for monitoring and managing traditional harvest due to the specific local context for planning, managing and conservation. Since the 2011 assessment, the workforce of Indigenous rangers has grown around Australia and this has increased the on-ground capacity for monitoring the traditional take (e.g., GBRMPA, 2011; DIPF, 2013). In the Great Barrier Reef, as part of a Traditional use of marine resource agreement (TUMRA), Traditional owners are required to monitor, record and report traditional harvest activities (GBRMPA, 2008). In the Northern Territory, Indigenous rangers record information on the loss or return of aquatic species (e.g. fish, dugong, turtles) in their patrol areas (DIPF, 2013). Kimberley coastal communities are advancing with developing and implementing monitoring and evaluation frameworks (Jackson et al., 2015). Wide scale involvement of Indigenous rangers in monitoring programs also occurs in the Torres Strait (Johnson et al., 2015). Even with increased effort dedicated to Indigenous natural and cultural resource management, results have been mixed, with many projects falling well short of both Indigenous and non-Indigenous expectations (Barbour & Schlesinger, 2012). Natural and cultural resource management is considered a worthy and necessary goal (Ens et al., 2012), yet designing and implementing programs to achieve sustainability goals are not straightforward (Dressler et al., 2010). Determining whether traditional harvest is sustainable needs to be assessed on a case-by-case community basis given the wider ecological and pressure conditions within an area and as such, it is important to consider the state of the harvested population, state of supporting habitats, range of threats, and controls to limit human impacts. DATA STREAM(S) USED IN EXPERT ASSESSMENT The information used in the assessment was based on extracting insightful statements from reports and articles across Australia on Traditional use of marine resources. No data sets were used to generate this assessment. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Since 2011, focus had been placed on monitoring and recording harvest levels to help quantify trends in Traditional use of marine resources.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with marine mining". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE A wide variety of mineral resources exist within Australia’s maritime jurisdiction (see Table 1 in attached Expert Assessment). Mining of those resources however, remains an 'emerging industry'. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports. Assessment has been completed by literature review. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Limited evidence or limited consensus Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Climate and system variability as a pressure on the marine environment was not assessed in 2011.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment - climate change - ocean currents and eddies". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Ocean Currents and Eddies" DESCRIPTION OF PRESSURE Australia’s shelf and coastal environment is largely controlled by the dominant Australian boundary currents including the East Australian Current (EAC), Indonesian Throughflow (ITF) and Leeuwin Current (LC), South Australian Current (SAC), Holloway Current (HC), and Zeehan Current (ZC) (Figure 1). The EAC is the western boundary current system of the South Pacific (Oke et a., 2019 and reference therein). In the Australian region, it redistributes heat and carbon between ocean and atmosphere, and between the tropics and mid-latitudes. The ITF, a major component of the global ocean circulation, moves water from the Pacific Ocean to the Indian Ocean (Sprintall et al., 2019 and reference therein). It strongly influences Australian climate and seas off Western Australia. The LC flows southwards off Western Australia redistributing Indian Ocean heat to the mid-latitudes. This differs from the cooler, equatorward flowing currents found along other eastern ocean boundaries. DATA STREAM(S) USED IN EXPERT ASSESSMENT The assessment is based on the results of analysis published in peer reviewed papers. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: Very high impact Assessment trend: Deteriorating Confidence grade: Adequate Confidence trend: Deteriorating Comparability: Grade and trends are somewhat comparable to the 2016 assessment. • 2016 • Assessment grade: High impact Assessment trend: Deteriorating Confidence grade: Adequate Confidence trend: Deteriorating CHANGES SINCE 2016 SOE ASSESSMENT We have seen significant marine heatwaves and cold events since 2016. The duration and frequency of these events impact the marine ecosystem and industry.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment - shipping (marine vessel activity)". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Shipping (marine vessel activity)" DESCRIPTION OF PRESSURE Australia as an island relies heavily on shipping for transportation of its domestic freight and international imports and exports. Australia relies on sea transport for 99 per cent of its international trade (by volume) [1]. In the 2017/18 financial year approximately 1554 million tonnes of cargo were loaded (+21.9% increase since 2013/14), and 155 million tonnes discharged (+2.6%) at Australian wharves by 5859 vessels (+6.5%) that made 34,117 port calls (+18.8%) [2]. As well as commercial vessels, many smaller vessels use Australian waters and provide an important recreational pastime for many Australians. DATA STREAM(S) USED IN EXPERT ASSESSMENT not supplied 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: Low impact Assessment trend: Deteriorating Confidence grade: Adequate Confidence trend: Limited Comparability: Grade and trend are comparable to the 2016 assessment • 2016 • Assessment grade: Low Assessment trend: Deteriorating Confidence grade: High level of consensus Confidence trend: High level of consensus Comparability: Comparable • 2011 • CHANGES SINCE 2016 SOE ASSESSMENT No change.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment - climate change - frequency and severity of extreme weather events". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Frequency and Severity of Extreme Weather Events" DESCRIPTION OF PRESSURE Extreme weather events represent pressures to the marine and coastal environments through severe storm-induced winds (including tropical and extratropical cyclones) which can cause wind damage and storm surges, heatwaves or shorter-term heat extremes which can stress infrastructure and natural barriers, extreme rainfall events which can cause flooding and erosion, and extreme dry conditions – in particular drought – which can stress natural coastal systems such as mangroves. Aside from the delimited identification of cyclones as either tropical (north of the Tropic of Capricorn (ToC)) and extratropical (south of the ToC), all other listed pressures can affect all coastal regions of Australia. DATA STREAM(S) USED IN EXPERT ASSESSMENT Literature. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: High impact Assessment trend: Unclear Confidence grade: Somewhat adequate: Adequate high-quality evidence or high level of consensus at a national scale Confidence trend: Limited evidence or limited consensus Comparability: N/A – new assessment CHANGES SINCE 2016 SOE ASSESSMENT Not previously assessed.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "The state and trends of quality of habitats and communities – Seamounts". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF HABITAT/COMMUNITY FOR EXPERT ASSESSMENT Seamounts (undersea mountains, often with volcanic origin) provide ‘oasis’ habitats of hard substratum and are widely considered to represent sites of elevated biomass and productivity in the deep ocean. Their habitats can support dense aggregations of corals and associated high biodiversity; these represent vulnerable marine ecosystems (VME) (e.g. UNGA 2006; Clark et al 2011). The geological definition of a seamount (elevation of >1000 m) has no relevance to biodiversity valuation because smaller features are frequently found to support high, if not the highest, biodiversity. An ecological definition (e.g. Pitcher et al. 2007) is recommended. Australia’s marine realm encompasses many seamounts; the best known are the Tasmanian seamounts and the Tasmantid seamount chain. Additional seamounts have been discovered and mapped on the Lord Howe Rise and the Norfolk Ridge, as well as on Australia’s southern margin in the GAB. Seamount communities to ~1500 m depth in the south-east and south-west regions are associated with biogenic habitats formed mostly by the stony coral Solenosmilia variabilis (Koslow et al 2000; Thresher et al. 2014). Its matrix of dead and life coral, built up to a layer of at least 1.6 m thickness in places, forms a habitat for other corals, urchins, brittle- and snakestars and crustaceans (Thresher et al. 2014). Communities and habitats on deeper reaches of seamounts (>1500 m) are less well studied; they are usually less diverse and sparser, although areas of extraordinary high biomass have been observed in the south-east region (Thresher et al. 2014). The seamounts in the Tasmantid chain are mapped and well used by various commercial fisheries, but their epifaunal communities remain poorly documented (Williams et al. 2012). DATA STREAM(S) USED IN EXPERT ASSESSMENT This assessment is based on data derived from Marine National Facility Surveys described in MarLIN (http://www.marine.csiro.au/marlin/search.html) and accessible through the CSIRO Data trawler (http://www.cmar.csiro.au/data/trawler/). Links to specific data sets are provided in the "On-line resources" section of this record. • Voyage of Discovery north-west (SS05/2007) • Voyage of Discovery south-west (SS07/2005 & SS10/2005) • Tasmanian seamounts surveys (SS01/2000, SS04/2006 & SS02/2007, SS01/2008 & TT01/2008) • Habitat Mapping (SS01/2000, SS04/2004) • Habitat and population assessment of giant crabs (2003 - 2005) • NORFANZ survey of Lord Howe Rise and Norfolk Ridge (TAN0308 - NORFANZ) 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Very good-Poor Assessment trend: Stable- Improving Confidence grade: Adequate high quality evidence and high level of consensus Confidence trend: Adequate high quality evidence and high level of consensus Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT There is substantial information on the impact of trawling on seamounts in the South-East Marine Region available.