A chance discovery off the Gisborne coast five years ago is prompting a NIWA scientist to find out more about the link between a field of methane seeps bubbling out of the sea floor and submarine landslides.
The on-going rise of atmospheric carbon dioxide (CO2) that is fuelling climate change is also driving significant changes in the waters off our coasts.
A decade of scientific research into how ocean acidification is affecting New Zealand waters has led to far greater understanding of the vulnerability of our marine ecosystems, according to a newly published review.
Our oceans are expected to become more acidic as carbon dioxide concentrations rise. This will likely have impacts on the plankton, which play a major role in ocean ecosystems and processes.
NIWA ocean geologist Dr Joshu Mountjoy explains how the R.V. Tangaroa's multibeam system is used for bathymetric (seabed) mapping, and some of the benefits which come out of this mapping.
NIWA marine geologist John Mitchell gives a brief history of bathymetric (seabed) charting, and how it's been carried out over the last few hundred years. (01:18)
Tagging White Sharks off Stewart Island, NZ Scientists from DOC, NIWA, and the University of Auckland are building a unique picture of New Zealand's great white shark population.
Voyage Log and Latest Images
Voyage plot for RV Tangaroa.
Time: 2004-04-14 02:00:00
Position: 41 33. 36S 178 24. 00E
As time permitted, scientists on the SAGE voyage posted descriptions of their daily activities and images of the work they were doing. The voyage track shows the position of RV Tangaroa as the experiment progressed.Thursday, 15 April 2004The final dayAs the SAGE voyage comes to an end, it is only fitting that we have the best weather of the month. After all, we did ask for strong wind conditions to assist in giving high gas exchange, and we certainly got it.
Up until November 2008, this was a joint quarterly update from the National Centre for Coasts and the National Centre for Oceans. The publication facilitates public, industry, and governmental access to NIWA's expertise and knowledge in coastal and ocean research.
NIWA (National Institute of Water and Atmospheric Research), New Zealand
University of Otago, New Zealand
Australian Government Analytical Laboratory
Bureau of Meteorology, Australia
CSIRO Atmospheric Research, Australia
Southern Cross University, Australia
Dalhousie University, Canada
Laboratoire D'Océanographie Dynamique et de Climatologie (LODYC), France
Lamont Doherty Earth Observatory, Columbia University, USA
Plymouth Marine Laboratory, United Kingdom
Princeton University, USA
RSMAS, University of Miami, USA
University of Colorado at Denver, USA
Univer
Wednesday, 14 April 2004
A view from the crew
This is the second of this type of research programme involving iron fertilisation that this crew have been involved in, with the first being SOIREE in 1999. The knowledge accumulated then has been useful to us this voyage. This is probably just as well since this one has, in many ways, been far more challenging. Probably the most notable difference, least not from the crew perspective, has been the weather. This time the Southern Ocean has been living up to its reputation.
Tuesday, 13 April 2004
Get more go on moorings
Sometimes the God of the Sea, Tangaroa, plays a vital role in deciding the milestones and outcomes of oceanographic voyages. Yesterday was a case in point with strong westerly winds and a heavy, rough sea, which prevented us from recovering and re-deploying one of NIWA’s two deep-ocean biophysical time-series moorings. These have been deployed in the open ocean east of New Zealand over the last 3.5 years.
Monday, 12 April 2004
Rolling with the punches
We had to leave the South Biophysical Mooring station before breakfast. The plan had been to conduct a deep CTD cast, and recover the mooring, but 50-knot winds and 6–8-metre swell prevented this. At sunrise the ship headed north to Chatham Rise. This resulted in the ship taking big rolls, hampering almost all activities, including sleeping. The rough sea did not however prevent deploying the second French Carioca Buoy in the area.
Sunday, 11 April 2004
Bunny hopping on the Southern Seas
Despite winds gusting to 50 knots and breaking waves reaching 6 m, and under conditions which seasoned 1st mate Alexander Morrice described from the bridge as “fierce to ferocious, becoming fantastic at times”, the Easter Bunny still managed to sneak in under the radar and visited the RV Tangaroa overnight. Little parcels of chocolate eggs were found taped outside everyone’s cabin doors.
Saturday, 10 April 2004
Steaming onwards
After a couple of pre-dawn CTD casts this morning, we slowed down to make measurements in the vicinity of the French CARIOCA buoy. We have finally left the patch that we’ve spent nearly 3 weeks chasing around this area of the South Pacific. We started to see increases in the number of phytoplankton cells toward the end of the patch experiment. It has been hypothesized that once the many cloudy days finally broke into sunshine, the phytoplankton were no longer light limited.
Friday, 9 April 2004
Sifting the seas
Today is our penultimate day of patch occupation! The SF6 shows that the patch is holding together fairly well, and the phytoplankton are still healthy. I measured the chlorophyll a concentration this morning in the patch and it hasn’t really changed significantly in two days. We are all still a little perplexed by why there hasn’t been a much larger increase in plankton, but it has certainly been interesting to follow and try to figure out.
Thursday, 8 April 2004
Scrutiny on the Bounty Trough
Careful what you wish for; you might just get it. We’ve had the extreme winds that gave us the high gas exchange we’d hoped for, putting folk on their backs, instruments on the deck and the ship hove to for a day. Then high mixing and rapid spreading, resulting in a highly mobile patch that led us a merry dance around an eddy. Now we need the biology to play ball.
Things here are looking positive, with the biological indicators moving in the right direction following the 4th iron addition two nights ago.
Wednesday, 7 April 2004
A plankton brew
It was a late night. We had our first and probably only opportunity to run Go-flow bottles for trace metal chemistry tonight. I was assisting Mike Elwood with this sampling, which he estimated would take about 3 hours but it ended up taking us around 6 hours.
Tuesday, 6 April 2004
A sign of things to come?
It’s a clear, calm, low-flux day here in the patch, though we are hardly aware of that in our lab down in the bowels of the ship. The CO2 lab is below the water line – a nice stable place in the ship, though we can’t tell if it’s day or night, sunny or cloudy. Twice a day we emerge to take water samples from the CTD casts (in-patch and out-patch stations) then it’s back below to analyze the water for pH and alkalinity, from which we calculate total inorganic carbon concentration.
Monday, 5 April 2004
Science on the high seas
Today was very much like others – high winds, intervals of sun, and some rain showers. There was swell of few metres running for most of the day. The routine of mapping the patch continues, with CTDs both inside and outside the fertilized area. With the passage of time it has become apparent that the patch is moving clockwise around an eddy.
Sunday, 4 April 2004
Dawn at dusk
As was previously mentioned, we took another stab at trying to buff up the phytoplankton by, as Peter Minnet so eloquently put it, "pumping iron" into the patch yesterday. We are now waiting to see if the phytoplankton respond to this.
I am involved in the atmospheric chemistry group (along with Mike Harvey, Jill Cainey, and Murray Smith), specifically looking at aerosol chemistry.
Saturday, 3 April 2004
It’s on our radar
After a night of winds reaching 50 knots, the weather settled today, and towards evening we had a short period when there was none discernible. There is still a 2–3 m swell remaining. Today we re-infused the patch with more iron, to maintain the enhanced biological activity.
I spend most of my time looking after the ocean remote-sensing radar. This consists of an antenna, bolted to the starboard railing below the bridge, connected to the signal processing electronics and associated computers in the science area on the bridge.
Friday, 2 April 2004
Dissolved dimethylsulphide (DMS) is being determined onboard by Associate Professor Graham Jones (Southern Cross University, Australia), Mike Harvey and John McGregor (NIWA), and Hilton Swan (Australian Government Analytical Laboratories, Sydney). A measurement is being made every 14 minutes and this data with sea surface temperature and wind speed measurements will be used to calculate the flux of DMS as Tangaroa samples in and out of the patch.
Thursday, 1 April 2004
No fooling around
It’s been a good couple of days. A break in the weather after we rejuvenated the patch with iron and tracer has enabled us to play catch-up with a couple of sampling techniques. This is an important period as the reduced wind enables near-surface waters to stratify, forming layers near the surface. The stratification affects how nutrients and phytoplankton are circulated as well as mediating rates of mixing due to breaking waves.
Wednesday, 31 March 2004
It’s déjà vu time
As Mike Harvey mentioned in the previous weblog, we had decided to re-infuse what remains of our patch with more iron and tracers. This started last night.
Complicated procedures often seem to go more smoothly the second time around, and the second iron/tracers infusion was no exception. Unlike the first time, where it took many days (and a detour) to have a working GC/TCD (gas chromatograph/thermo conductivity detector), Andrew Marriner and Peter Hill were able to get the GC/TCD up and running after less than one hour.
