Sponge gardens of Ningaloo Reef (Carnarvon Shelf, Western Australia) are biodiversity hotspots

Abstract

During a multi-agency Australian Government initiative sponges were sampled at three areas from Carnarvon Shelf, NW Australia. Sponges were identified to lowest possible level, largely as morphospecies (84%). A searchable and interactive taxonomic catalogue was created and is publicly accessible through the Ningaloo Atlas collated by the Australian Institute for Marine Science. The sponge gardens on Carnarvon Shelf are patchily distributed but highly diverse and occasionally extremely dense. We examined 754 specimens and distinguished 261 species belonging to 112 genera. Species accumulation curves indicate that this species number does not represent local sponge biodiversity, which is projected to reach up to 840 species with additional sampling. Many observed species appear to be new to science, 81% occurred only at one of the three areas, about 56% were singletons, and 76% had a wet weight of B500 g. Detailed spatial analyses were difficult due to sampling design, but general trends could be detected. The northern areas, where the Australian continental shelf is narrowest, favour sponges with a higher content of inorganic skeleton and growth forms able to withstand the strong tidal currents and exposure typical for this area. Sponges were most abundant at the shelf edge, where massive forms dominated. While the central and northern areas are protected by zoning regulations, the southern area had the highest species diversity, the largest individuals and the densest distributions, suggesting additional conservation measures may be required. Western Australia is clearly an important, but understudied bioregion for sponges, and future research foci are proposed.Electronic supplementary material The online version of this article (

Changes in deep reef benthic community composition across a latitudinal and environmental gradient in temperate Eastern Australia

“…6; Tables 3−5). Depth gradients in benthic sessile invertebrate assemblages have been a consistent pattern to emerge from cross-shelf studies in Western Australia (Fromont et al 2006, Schönberg & Fromont 2012, the Great Australian Bight (Ward et al 2006), northern Queensland (Wilkinson & Cheshire 1989, Hooper & Kennedy 2002, Bridge et al 2011) and off the coast of Sydney, New South Wales (Roberts & Davis 1996, Roberts et al 2006. However, depth acts as a robust surrogate for several other environmental variables, such as temperature, light availability, organic matter, slope or dissolved oxygen (Bridge et al 2011, Compton et al 2013, Pilditch et al 2015, so identifying the mechanism behind the pattern is non-trivial.…”

“…The effects of climate-driven shifts in benthic invertebrate communities, in particular the loss of species and functional diversity, may have broad ecological implications given that these sessile invertebrates provide essential services (e.g. food and habitat) to benthic species (Fromont et al 2006, Bell 2007, Schlacher et al 2010, Schönberg & Fromont 2012) and ecosystem functioning (e.g. nutrient recycling; de Goeij et al 2013).…”

“…On deep mesophotic (depth > 30 m) temperate reefs, sessile invertebrates, including sponges, cnidarians, ascidians and bryozoans, dominate and contribute to the diversity, structure and functioning of benthic ecosystems (Fromont et al 2006, Bell 2007, Schlacher et al 2010, Schönberg & Fromont 2012. Larger sessile invertebrates, in particular sponges, gorgonians and octocorals, provide essential structural and functional ecosystem services, including nutrient provisioning and recycling (de Goeij et al 2013) (i.e.…”

“…Larger sessile invertebrates, in particular sponges, gorgonians and octocorals, provide essential structural and functional ecosystem services, including nutrient provisioning and recycling (de Goeij et al 2013) (i.e. benthic−pelagic coupling), as well as provision of complex habitat and refuge for other organisms (Fromont et al 2006, Bell 2007, Schlacher et al 2010, Schönberg & Fromont 2012.…”

Effects of combined dredging-related stressors on sponges: a laboratory approach using realistic scenarios

“…Sediments released into the water column by natural resuspension, river runoff and human activities such as dredging pose a potential risk to sensitive ecosystems such as coral reefs, seagrass meadows and sponge gardens 1–4 . Sediments in suspension, or settling back out of suspension (i.e.…”