The likelihood of observing dust-stimulated phytoplankton growth in waters proximal to the Australian continent
Cropp, RA and Gabric, AJ and Levasseur, M and McTainish, GH and Bowie, AR and Hassler, CS and Law, CS and McGowan, H and Tindale, N and Viscarra Rossel, R, The likelihood of observing dust-stimulated phytoplankton growth in waters proximal to the Australian continent, Journal of Marine Systems, 117-118 pp. 43-52. ISSN 0924-7963 (2013) [Refereed Article]
We develop a tool to assist in identifying a link between naturally occurring aeolian dust deposition and phytoplankton
response in the ocean. Rather than examining a single, or small number of dust deposition events, we
take a climatological approach to estimate the likelihood of observing a definitive link between dust deposition
and a phytoplankton bloomfor the oceans proximal to the Australian continent.We use a dust stormindex (DSI)
to determine dust entrainment in the Lake Eyre Basin (LEB) and an ensemble of modelled atmospheric trajectories
of dust transport fromthe basin, themajor dust source in Australia. Deposition into the ocean is computed as
a function of distance fromthe LEB source and the local over-ocean precipitation. The upper ocean's receptivity to
nutrients, including dust-borne iron, is defined in terms of time-dependent, monthly climatological fields for
light, mixed layer depth and chlorophyll concentration relative to the climatologicalmonthly maximum. The resultant
likelihood of a dust-phytoplankton link being observed is then mapped as a function of space and time.
Our results suggest that the Southern Ocean (north of 45°S), the North West Shelf, and Great Barrier Reef are
ocean regions where a rapid biological response to dust inputs is most likely to be observed. Conversely, due
to asynchrony between deposition and ocean receptivity, direct causal links appear unlikely to be observed in
the Tasman Sea and Southern Ocean south of 45°S.