Australia 2016-2017 report

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Cruises: o  RV Akademik Tryoshnikov: Leg 1, 20 December 2016 – 17 January 2017.

Southern Ocean (GEOTRACES PI: Ellwood) o  RV Aurora Australis Voyage V1, December – January 2017, Antarctica, Mertz

glacier region (GEOTRACES PIs: Lannuzel, Noble). Sea water and sea-ice samples were collected for micro-nutrient and Nd isotope measurements.

o  RV Investigator, Jan – March 2017, Sabrina Seafloor Survey Antarctic margin (Totten glacier) (GEOTRACES PI: Noble). Sediment cores and large-volume seawater samples for Nd isotopic analysis were collected to investigate the interaction of the Totten Glacier with the Southern Ocean during the last deglaciation

o  RV Investigator March 2017. Subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site (GEOTRACES PIs: Boyd, Ellwood, Bowie). Collected dissolved and particulate trace metal samples. First successful deployment of the RESPIRE particle interceptor trap, for coupled measurement of trace metal remineralization and respiration rates. (Process study)

Australia 2016-2017 report

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Outputs: o  19 publications o  4 PhD theses

New projects and/or funding: o  ARC Discovery Grant, “Spinning the ferrous wheel: how is iron cycled in

Southern Ocean waters?” Ellwood, Boyd, Armand, Wilhelm, Twining o  ARC LIEF funding, “A multi-institutional environmental radioactivity

research centre” GEOTRACES CIs Masque, Boyd, Chase

Two shiptime awards for 2018-19 season: o  PIs Ellwood, Boyd, Chase, Abbott, Bowie. “Constraining external iron inputs

and cycling in the southern extension of the East Australian Current”, 23 days shiptime on RV Investigator in 2018-19

o  PIs Boyd, Ellwood, Bowie. “Surface and subsurface subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site”, 16 days shiptime on RV Investigator in 2018-19

Australia 2016-2017 report

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Up coming voyages (next 12 months): o  SR3-GEOTRACES repeat transect (GEOTRACES PI: Bowie) “Detecting

Southern Ocean Change From Repeat Hydrography, Deep Argo And Trace Element Biogeochemistry” (Southern Ocean section from Tasmania to Antarctica) voyage in January/February 2018 (45 days). The SR3 section was previously occupied during IPY-GEOTRACES in 2008, and we have the opportunity to expand the GEOTRACES measurements and spatial resolution on the 2018 voyage. To be proposed as GEOTRACES section

o  SOTS time series (GEOTRACES PIs: Boyd, Ellwood, Bowie) “Subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site” South of Tasmania, voyage in March 2018 (20 days)

o  Two transit voyages around Australia under the project “Natural iron fertilisation of oceans around Australia: linking terrestrial dust and bushfires to marine Biogeochemistry” (PI Bowie) will provide GEOTRACES compliant aerosol data

Courtesy Tom Holmes

Heard Earth Ocean Biosphere Interaction (HEOBI)

Dec 2015-Feb 2016 MODIS chl a

Volcano + glacier

Photo: Pete Harmsen

Seafloor bubbles

Island sources of iron

Shallow coastal waters near Heard and McDonald Islands have 1-3 nM dFe

Int.chl-a

SB

Fig 4: dFe in different sectors of the K-axis region: •  A = south of the SB

except coastal •  B = coastal •  C = where chl-a

was highest

Elevated subsurface dFe coincides with high chl-a; upwelling of this dFe could fuel the sustained phytoplankton bloom in the area (Fig 3)

•  Fig 1: High chl-a north of the Southern Boundary (SB)

•  Fig 2: Tracer release experiment in general circulation model; tracer coming up in the area where high chl-a was observed

•  Fig 3: Chl-a climatology for February, showing a sustained bloom in the area late in the season

1 2 3

K-axischl-achl-a

Tracerrelease Chlaclimatology,Feb

Courtesy Christina Schallenberg

Australia 2016-2017 report

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Coming soon to the Southern Ocean: New Australian icebreaker

CTD moon pool deployment Larger, greater icebreaking, increased endurance

Naming contest closed; Delivery 2020

More information: http://www.antarctica.gov.au/icebreaker