The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the North Bruny Island region, and its 3 subsites: Patrick's Bight, Trumpeter Point and Yellow Bluff.

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the Forestier Peninsula region, and its 3 subsites: Sisters, Visscher Island and High Yellow Bluff.

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the St Helens region, and its 3 subsites: Binalong Bay, St Helens Island and St Helens Point

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the Bicheno region, and its 3 subsites: Denison, Governor Island and Lodi.

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the South Bruny Island region, and its 3 subsites: Mangana Bluff, Bay of Islands and Cape Conella.

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the Recherche region, and its 3 subsites: Eliza Point, Fisher Point and Actaeons.

Coral community transect data collected concurrent with coral disease surveys in in the vicinity of Hoga Island in the Wakatobi Marine National Park, Sulawesi, Indonesia. Three replicate 20 m transects were collected by divers in each of reef flat, crest and slope habitats in 2005 (four sites, point intersect transect data), 2007, 2010 and 2011 (all six sites, line intersect transect data). For further detail see: Haapkylä, J., A. S. Seymour, J. Trebilco, and D. Smith. 2007. Coral disease prevalence and coral health in the Wakatobi Marine Park, south-east Sulawesi, Indonesia. Journal of the Marine Biological Association of the UK 87:403. Haapkylä, J., R. Unsworth, A. Seymour, J. Melbourne-Thomas, M. Flavell, B. Willis, and D. Smith. 2009. Spatio-temporal coral disease dynamics in the Wakatobi Marine National Park, South-East Sulawesi, Indonesia. Diseases of Aquatic Organisms 87:105–115. Haapkylä, J., J. Melbourne-Thomas, and M. Flavell. 2015. The association between coral communities and disease assemblages in the Wakatobi Marine National Park, south-eastern Sulawesi, Indonesia. Marine and Freshwater Research.

The spatial extent of C. rodgersii "barrens" was estimated by surveying rocky reef habitat with a towed underwater video system. Sampling took place at 13 regions along the east coast of Tasmania, each comprising 3 subsites, this dataset refers to the Fortescue Bay region, and its 3 subsites: Lanterns, Munroe Bight and Thumbs.

Over the past fifty years, Eastern Tasmanian waters have experienced rapid warming, primarily due to the extension of the East Australian Current. This has driven expansion of warm-water biota and decline of those adapted to cooler conditions, including phytoplankton. Presently, plankton monitoring, including diatoms along Eastern Tasmania, spans <100 years. This study reconstructed diatom communities throughout a sediment core spanning 9,000 years before present (9 kyrs BP), using microfossil analysis and molecular techniques, including sedimentary ancient DNA (sedaDNA) and NRS 18S rRNA from a 10-year water column archive at the Maria Island IMOS NRS mooring. Microfossil analysis revealed a dominance of strongly silicified benthic taxa (Campylodiscus, Diploneis, Paralia, Pyxidicula, Triceratium). Notably, Paralia sulcata showed a shift ~6 kyrs BP from small to larger cells, possibly reflecting a transition from a coastal to shelf ecosystem. However, microfossils underrepresented lightly silicified planktonic diatoms. Molecular methods detected higher diatom diversity, though up to 50% of sedaDNA reads remained unclassified due to reference library limitations. Lightly silicified planktonic genera (Chaetoceros, Corethron, Lithodesmium, Rhizosolenia) were identified only via molecular approaches and comprised 73% of sedaDNA and 88% of 18S rRNA records. Of 10 shared diatom families, 5, 15, and 4 were unique to microscopy, sedaDNA, and 18S rRNA, respectively. SedaDNA also captured greater benthic diversity. Our findings revealed limitations in reconstructing historic diatom assemblages from sediment cores. Microfossils faced constraints due to difficulties in morphological identification and preservation biases. In contrast, sedaDNA analysis yielded finer taxonomic resolution, provided access to high-quality reference sequence libraries were available.