2021 State of the Environment Report Marine Chapter – Expert Assessment – State and Trend – Deepwater corals and sponges (dark, > 150 m)

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 "State and Trend of deepwater corals and sponges (dark, &gt; 150 m)". 
<strong><em>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 - Deepwater Corals and Sponges (dark)"</em></strong>



DESCRIPTION OF HABITAT/COMMUNITY/PROCESS FOR EXPERT ASSESSMENT
Corals and sponges are habitat-forming biota that enhance benthic biodiversity in the deepsea by providing complex structural living spaces for a large number of species from a variety of taxa (Buhl-Mortensen et al. 2010, Fromont et al. 2012). Many species form prominent colonies attached to hard seabed, others are well adapted to living on soft sediment.
Coldwater corals include stony corals (Scleractinia), black corals (Antipatharia), and octocorals (Alcyonacea) (Fig 1). Knowledge of deep-sea octocoral diversity and distribution in Australia has expanded recently (Alderslade et al., 2014; Althaus et al., 2017; Williams et al. 2020), including the identifying of distinct depth bands occupied by different species. 
Deepwater sponges include demosponges, calcareous and glass sponges (Fig1). Demosponge richness and abundance decreases with depth and latitude; glass sponges show an opposite trend (Fromont et al. 2012).  Seamounts are dominated by lithistid (rock sponges). Calcareous sponges are regarded as deep-sea tropical sponges, which have retreated from the shallows over geological timeframes. Recent collections of carnivorous sponges from eastern and southern Australia have shown some of the highest diversity in the world (Ekins et al. 2020a; 2020b). 

DATA STREAM(S) USED IN EXPERT ASSESSMENT
This assessment is based on data from several Marine National Facility Surveys (available via 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.
 • Challenger Expedition 1873-1876 
 • CIDARIS, The Deep Sea Bottom Fauna of the Barrier Reef Shelf and Adjacent Coral sea, 1986 (RV Franklin FR 3/86, FR 03/86)
 • Deep Down Under Expedition, 2009 
 • Seamounts, Canyons &amp; Reefs of the Coral Sea 
 • Visioning the Coral Sea Marine Park 
 • Sampling the Abyss (IN2017_V03)
 • NORFANZ survey of Lord Howe Rise and Norfolk Ridge (TAN0308 – NORFANZ)
 • Tasmanian Seamounts surveys (SS01/1999, SS02/2006, SS02/2007, SS01/2008, TT01/2008, IN2018_V06)
 • Great Australian Bight Deepwater Marine Program (GABDMP) (IN2015_C01, IN2017_C01, IN2015_C01, RE2017_C01)
 • Great Australian Bight Research Program (GABRP) (SS2013_C02, IN2015_C02)
 • The great Australian Deep-sea coral and canyon adventure 
 • Voyage of Discovery south-west (SS07/2005, SS10/2005)
 • Habitat and population assessment of giant crabs (2003 - 2005) (SS07/2005, SS10/2005)
 • Illuminating Biodiversity of Ningaloo Canyons 
 • Voyage of Discovery north-west (SS 05/2007)



2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]

• 2021 •
Assessment grade: Poor - Good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus
Comparability: Grade and trends are somewhat comparable to the 2016 assessment
• 2016 •
Assessment grade: Poor - Good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus
Comparability: Grade and trends are somewhat comparable to the 2011 assessment
• 2011 •
Assessment grade: Good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus



CHANGES SINCE 2016 SOE ASSESSMENT
not supplied

Tags: biogenic habitat, coral, deepwater invertebrates, expert assessment, sponge
Organization: Australian Ocean Data Network