Data Trawler - Project details

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Project details

Title: Inorganic Nitrogen uptake
Id: 2522
Investigator(s): Anya Waite

Description: The scientific objective of this work is to map, for the first time, the genomic characteristic of marine bacteria and phytoplankton along 170°W, as part of a larger set of surveys being carried out around Australia. While we are getting better insights in the microbial community and their taxonomy, uptake and rate measurements of N and C are still very sparse throughout the wold oceans and are a high priority to accurately quantify C, N cycles and the associated primary productivity. Especially as we have to keep in mind that numerically outnumbered microbes can play a significant role in the N and C cycles of their ecosystem. Previous studies have shown that the least abundant species (in this case the anaerobic, phototropic bacteria Chromatium okenii representing ~0.3% of the total cell numbers), can contribute more than 40% of the total NH4+assimilation and up to 70% of the total C fixation. We will investigate the role of microbes in the N uptake. While we may be able to get presence absence using techniques such as quantitative polymerase chain reactions (qPCR), metagenomics or high through put sequencing, isotopes (stable isotopes) are necessary to measure rates of nutrient utilization/remineralization. We will take water from the level 02 flow through system near the Isotope Lad (Radvan). No special requirements with regards to the vessel’s course or speed are required. All sampling will be aligned with the CTD stations.
Years: 2016

List of surveys that this project was on.

Use [details] link to view survey details (map, reports, metadata etc) including links to download data.

Survey InvestigatorDescription

B. Sloyan (CSIRO, O&A) RV Investigator research voyage in2016_v03. Titled Monitoring Ocean Change and Variability along 170oW from the ice edge to the equator This voyage involves two legs from Hobart to Wellington(NZ) and Wellington(NZ) to Lautoka(Fiji). Voyage objectives of the major project - Monitoring Ocean Change and Variability along 170oW from the ice edge to the equator are: The primary voyage objective is to obtain repeat occupations of the 155 full-depth CTD and Niskin casts along the GO-SHIP P15S section, with chemistry performed on water collected at 36 bottle levels. We will measure temperature, salinity, pressure, oxygen, fluorometry, shear and micro-scale temperature continuously, and the major nutrients, oxygen, salinity, CFC and carbon components discretely via chemical analysis on board. Small amounts of material will be filtered and stored for genomic analyses back on land. CSIRO has completed this line twice before and international groups have completed similar work along lines further east. The work plan and timings are based on these past voyages. Argo float deployments will also be carried out - usually when just leaving a CTD station (SOCCOM floats) or during transit (we may slow the ship speed slightly). These will be over the ship's stern (preferred). Voyage objectives of the supplementary project -Facing the challenges of under-ice for autonomous navigation are: Accurate navigation under both drift and stationary ice is one of the key unanswered questions in polar marine science and engineering. The primary aims of this project are to (1) estimate INS drift and calibration times; and, (2) test the integration of acoustic positioning methods in an INS within a drifting and rotating frame of reference. This project will develop error propagation models at increasing latitudes and test the use of a non-stationary, ship borne acoustic positioning network on a small (<3 m) AUV. Both are critical for robust, accurate and reliable AUV operation under-ice. The primary voyage objective is make measurements of inertial drift during vessel transit and calibration time while the Investigator is on station across as broad a range of latitudes as possible. The way that this will be achieved is that, while the vessel is on station, bench top tests will be conducted for alignment. Then, while moving, tests of inertial drift will be conducted. The student on board will work with the other PIs on board to coordinate timings of these tests but will not disrupt the other work taking place on board. The work plan and timing is based on methodologies established during past voyages. Full details can be found in the in2016_v03 voyage plan. Previous MNF voyages include RV Franklin FR 05/2001 and RV Southern Surveyor SS200901.
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