2016 SoE Marine Chapter - State and Trends - Water column, inner shelf (0 - 25 m)

Brief description

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 habitats and communities - water column, inner shelf (0 - 25 m)". 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 Based on biomass the major communities found in the water column are phytoplankton>bacteria>zooplankton>fish (Marchant 2002). The water column is the habitat and the major determinants of quality for most pelagic organisms can be considered to be temperature (T), salinity (S), light, nutrients, dissolved oxygen (DO), pH, and food availability. The inner shelf waters around Australia are generally warm, mostly saline, well illuminated, low in nutrients, and phytoplankton, zooplankton and fish abundance. The inner shelf is also the pelagic marine habitat most exposed to human induced pressures and has local habitats that range from heavily disturbed to pristine. The capability of this habitat to support the existing flora and fauna can be considered to be under threat (e.g. Game et al. 2009) from: inputs from the terrestrial environment (e.g. sediments in runoff or due to increased erosion, nutrients, wastes), harvesting of biota, invasive species, infrastructure development (e.g. impoundments, harbours, hardening), mariculture, mining, oil and gas extraction, climate change (warming, falling DO, decreasing pH). There are many areas of local habitat degradation, with the most impacted areas tending to be embayments and estuaries with significant population pressures and limited exchange (e.g. Alyazichi et al., 2015; Mckinley et al., 2011). In spite of improvements in the management of these types of pressures the magnitude of the growth in mineral exports, agriculture exports and population growth would suggest that development impacts will have risen. At the same time across many jurisdictions improvements in sewage treatment and disposal mean that potentially dangerous pathogens are increasingly rare. For example in 2015 96% of NSW open beaches with high rates of recreational use were rated good or very good (NSW EPA, 2015). At a larger geographic scale our shelf waters are experiencing increasing impacts from global pressures such as warming. Shelf waters from Port Hedland to Cape Howe have risen ~ 1°C from 1993 to 2013 (Foster et al., 2014), and portions of the SW region were 3°C warmer during February 2011 than normal (Pearce and Feng 2013). There is evidence that dissolved oxygen has declined (Thompson et al. 2009) and will continue to decline due to warming (Talley et al., 2016). This is likely to lead to more losses of marine fauna due to low oxygen; such as the unprecedented event during 2015 in Cockburn Sound (Pattiaratchi 2016). Recent blooms of toxic phytoplankton in regions where they never bloomed before (Campbell et al., 2013) and the SE shellfish that have suffered badly from disease outbreaks (Hooper et al., 2007; Lewis et al., 2012). There is evidence of widespread responses to climate related pressures across the major types of biota, phytoplankton, zooplankton and fish (e.g. Johnson et al. 2011, Thompson et al. 2016) as well as our coral reefs under increased stress from rising temperatures and declining pH (Mongin et al., 2016). DATA STREAM(S) USED IN EXPERT ASSESSMENT Data are computed from the level 3 (L3) daily global products using one merging method following Maritorena and Siegel, (2005). Details can be found at http://www.globcolour.info/products_description.html Phytoplankton and zooplankton data are from Australia’s National Reference Stations operated by the Integrated Marine Observing System. ---------------------------------------- 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Good 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: Good Assessment trend: Deteriorating Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus ---------------------------------------- CHANGES SINCE 2011 SOE ASSESSMENT Where possible this assessment includes a statistical analysis of trends in consistent measures of habitat and community around the country.

Lineage

Statement: QUALITY OF DATA USED IN THE ASSESSMENT Spatial and temporal coverage of satellite data are excellent. Conversion of ocean colour to chlorophyll a introduces a source of potential error that increases in turbid and nearshore waters. Improved regional assessments of state and trend are feasible using only data from each region. IMOS data are high quality but limited in spatial coverage.

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Purpose
To describe the state and trends in the quality of the water column community, inner shelf (0 - 25 m) for use in the Marine chapter of the 2016 State of the Environment report.