Marine phytoplankton bioregions in Australian seas

• Main Authors: Hallegraeff, Gustaaf M., Richardson, Anthony J., Coughlan, Alex
• Other Authors: Malte C. Ebach
• Format: Book Part
• Language: English
• Published: CRC Press 2017
• Subjects: 1100 Agricultural and Biological Sciences; 2300 Environmental Science; Antarctic; Antarctic Ocean; Indian; Ner; Saint-Vincent; Southern Ocean; The Antarctic; Wilkinson; Antarc*
• Online Access: https://espace.library.uq.edu.au/view/UQ:60fbf4b

Knowledge on the biogeography of pelagic phytoplankton serves (1) as a baseline for climate change and ocean acidication, (2) to assess the impact from human impacts such as eutrophication and ship ballast water introductions, (3) as a guide for natural resource planning and management, and (4) to provide insight into palaeobiogeography and understand drivers of biodiversity. The very rst known microalgal examinations from Australian waters date back to the world voyage by HMS Challenger in 1874, collecting in the Southern Ocean, the Bass Strait and the Tasman, Coral and Arafura Seas (Castracane 1886). A limited number of collections in Australian waters were also made on the German Valdivia expedition (1898-1899), which resulted in accounts of the phytoplankton from the Antarctic and Indian Oceans (Karsten 1905, 1907). More comprehensive early investigations on the taxonomy and distribution of Australian marine microalgae include those of the Great Barrier Reef region (Marshall 1933), the neighbouring Java Sea (Allen and Cupp 1935), Sydney coastal waters (Dakin and Colefax 1933, 1940) and the Australia-wide netphytoplankton surveys by Wood (1954, 1964a,b,c,d) and Crosby and Wood (1958, 1959). These early studies compared Pacic, Indian and Antarctic Ocean basins (Karsten 1905, 1907) or tried to compare Australian phytoplankton communities with those of better-studied European coastal waters (Dakin and Colefax 1933, 1940). The rst effort to produce an Australian map of marine phytoplankton provinces (based on dinoagellate associations) was provided by Wood (1954, 1964a,b; reproduced here as Figure 3.1). Although hampered by limited taxonomic discrimination, this work is impressive in its geographic coverage, but unfortunately, precise sample coordinates cannot be readily retrieved. These latter studies produced the rst conclusive biological evidence for the transport of Indian Ocean dinoagellates southwards along the west coast of Australia and all the way to the west coast of Tasmania (Wood 1954); this ow is now known as the Leeuwin Current. A subsequent bioregionalisation by Markina (1972, 1974, 1976) was limited to netphytoplankton from the west coast of Australia. In the period 1978-1984, as part of a series of CSIRO Division of Fisheries and Oceanography cruises, signi- cant advances in plankton collection methodologies (ner mesh plankton nets, water bottle sampling, more sophisticated preservatives, enrichment cultures), and notably the use of electron microscopy for species identication, considerably improved our knowledge of marine microalgal species communities in the Australian region. Denitive studies were published on the phytoplankton of New South Wales coastal waters (Hallegraeff and Reid 1986; Hallegraeff and Jeffrey 1993), East Australian Current eddies (Jeffrey and Hallegraeff 1980, 1987), the Coral Sea (Revelante and Gilmartin 1982; Revelante et al. 1982) and the North West Shelf and Gulf of Carpentaria (Hallegraeff and Jeffrey 1984). A new recognition at that time was the importance of delicate nanoplankton agellates (2-20 µm size) and minute coccoid picoplankton (0.2-2.0 µm size). These small size fractions accounted for up to 90% of the total phytoplankton chlorophyll biomass, except during episodic large diatom or dinoagellate blooms (Hallegraeff 1981). Few of these species would have been recognised in earlier studies that used harsh preservatives such as formaldehyde or Lugol' s iodine, or used coarse (> 20 µm mesh) plankton nets for collection. As elsewhere in the world, Australian nanoplankton is primarily composed of haptophytes (notably Chrysochromulina spp. and calcareous coccolithophorids; Hallegraeff 1983, 1984a; LeRoi and Hallegraeff 2004, 2006; Moestrup 1979), prasinophytes, small unarmoured dinoagellates, chrysophytes, cryptomonads and small diatoms (e.g. Minidiscus , Thalassiosira Hallegraeff 1984b), while the picoplankton fraction is composed predominantly of prokaryote cyanobacteria (e.g. Synechococcus) and prochlorophytes (e.g. Prochlorococcus) (Jeffrey and Hallegraeff 1987). Surprisingly, the nanoplankton species of Australian tropical and temperate inshore and offshore waters appeared morphologically remarkably similar. In contrast, the netphytoplankton diatoms and dinoagellates (20-200 µm size) could be differentiated into a temperate neritic community of the coastal waters of New South Wales, Victoria and Tasmania, a tropical neritic community conned to the Gulf of Carpentaria and North West Australia, and a tropical oceanic community in the offshore waters of the Coral Sea and Indian Ocean (rst summarised by Jeffrey and Hallegraeff 1990 and also covered by Hallegraeff 2007). Further phytoplankton species data that have become available since 1990 include: the Gulf of Carpentaria work by Rothlisberg et al. (1994), Burford et al. (1995) and Burford and Rothlisberg (1999); the Great Barrier Reef surveys by Furnas and Mitchell (1996, 1999); the New South Wales coastal studies by Lee et al. (2001), Ajani et al. (2001, 2013a,b, 2014), Farrell et al. (2013) and Armbrecht et al. (2014); the Western Australian cruises by Hanson et al. (2005) and Thompson and Bonham (2011); the South Australian Shellsh Quality Assurance Program (SASQAP) algal monitoring by Wilkinson (2005); the Gulf of Saint Vincent surveys by Leterme et al. (2014); the Bass Strait phytoplankton surveys by the University of Melbourne (e.g. Huisman 1989; McFadden et al. 1986); and the Tasmanian coastal phytoplankton surveys by Hallegraeff et al. (2010).