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Division of Sciences
www.otago.ac.nz/sciences
Sylvia Sander’s hydrothermal vents research
You can’t play “Spot the Difference” if you only have one picture to work with. Similarly, if you have a limited understanding of the natural biogeochemical
cycling of trace metals in the ocean, you can’t determine how that cycle is altered by sudden change – for example the possible impact of increased CO2
levels in the atmosphere.
Sylvia Sander has been exploring hydrothermal vents for the past two
decades; since joining Otago’s Marine and Fresh Water Chemistry
group she has also been looking at the biogeochemical cycles of trace
metals in the ocean. Her recently published Progress Article in Nature
Geoscience (Sander and Koschinsky, 2011, doi: 10.1038/ngeo1088) is a
result of this combined interest.
Hydrothermal vents in the sea floor release large volumes of hot, metalrich fluids into the deep ocean. Until recently, it was assumed that most
of the metal released was incorporated into sulfide or oxide minerals,
and that the net flux of most hydrothermally derived metals to the
open ocean was negligible.
The hydrothermal vents vary – they can be like geysers or more diffuse,
releasing hot water slowly through cracks in the ocean floor. These
more diffuse vents sustain a huge amount of life. It is probable that this
is where the metal-binding organic compounds come from.
“We think the copper binding compounds are amino acids or small
sulfur containing peptides. These are most likely to be produced as part
of biological processes in the various life forms that thrive around the
diffuse vents. It’s possible that simple organic compounds are produced
inorganically in the hot hydrothermal fluid, but these biological
processes are much more likely.”
Now, Sylvia has been able to prove that organic compounds bind to
and stabilize metals in hydrothermal fluids, increasing trace-metal flux
to the global ocean. This is a significant change in thinking about the
biogeochemical ocean cycle of these metals as a whole, and the role of
hydrothermal vents in particular.
“We used geochemical model simulations and showed that
complexation – the stabilising of trace metals using organic ligands
– significantly increases metal flux from hydrothermal systems.
According to our simulations, hydrothermal fluids could account for
9% and 14% of the deep-ocean dissolved iron and copper budgets
respectively. A similar role for organic complexation can be inferred for
the hydrothermal fluxes of other metals, such as manganese and zinc.”
Exploration of the hydrothermal vents and their unique properties has
become much easier over the time that Sylvia has been studying them.
“When we first used to look for them, the research vessel would do
sweeps, one way then another, using video cameras dragged over the
seafloor by the boat. Even if we had a rough idea where to look for
them, with a vent maybe the size of a room, it was easy to miss them.
Now we have advanced technology such as autonomous operated
vehicles (AUVs) that can sweep every quadrant in much finer detail.
Also the sensor technology is more advanced, picking up tiny but
significant differences of hydrothermal tracers. Once a new vent has
been located remote operator vehicles or manned submersibles are
used to have a close look and take high quality samples. ”
Sylvia Sander
Hydrothermal vents research
Janice Lord
Celmisia Cloaks
John Harraway
Revolutionise Statistics at your School!
There are changes afoot for
Hands-On Science this year – changes in
enrolment, eligibility and process.
Check the website for details:
www.otago.ac.nz/handsonscience
Janice Lord – celmisia story
Janice Lord is a botanist with an interest in alpine plants, and curator of
Botany’s herbarium (collection of dried plants and lichens).When Museum
conservator Moira White started work on a kete (basket) full of dried leaves,
she contacted Janice because they were documented as mountain daisy
leaves(Celmisia); Moira wanted to know what species of mountain daisy.
“The kete of leaves was found at Puketoi station in the Maniototo, along
with a number of other artefacts. The collection was photographed and
documented in 1890’s and that was about it. The Celmisia leaves in the
kete were very soft, almost like suede : a bit stretchy and still supple. The
size of the pieces suggested certain Celmisia species, but at that stage we
had no idea how the leaves had been processed to get them like that.”
That was the starting point of a new research journey for Janice.
The next step was a book researched and collated by Rua McCallum,
entitled He Kete Taoka, which describes cultural materials used by
southern Mäori. The section on Celmisia (Tikumu) described how
leaves would often be stripped, separating the tough top layer from the
felt-like white underside of the leaf. This was what had been done to the
leaves in the Puketoi kete. When Janice met Rua, a mätauranga Mäori
consultant, she found out more about the traditional uses of Celmisia.
“The whole leaf would be used to construct shin protectors and rain
capes, but the felt from the underside of leaves, called wharawhara, was
also highly prized for making cloaks. “
Given that there may be a number of artefacts made of Celmisia in
museums around the world, Janice thought it might be useful to
document distinguishing features of different Celmisia species. Drawing
on the Herbarium’s Celmisia collection she has put together a resource
kit of information giving species leaf dimensions, whether or not
the leaves can be stripped, and broad geographical distributions. She
hopes this information will make it easier for conservators to correctly
identify and look after their Celmisia artefacts.
Revolutionise Statistics at
your School!
The teaching of Statistics in schools has been revolutionised, giving
students the opportunity to use state of the art analytical software on real
problems to hone their skills.
John Harraway from Statistics has developed a set of teaching
resources – initially to enhance his own teaching in the Mathematics
and Statistics Department at Otago. But John very quickly saw
the relevance of these resources for secondary school teachers of
Statistics, so in consultation with local high school teachers he
extended their usefulness by adding teaching tasks that link the
resources to NCEA assessment standards.
With the help of the university’s Audio-visual Support and
Development Unit he has made a series of video clips of researchers
talking about using statistics in their research. Some of the presenters
are statisticians, and some are scientists who need to use statistics
for their work. The clips include examples from the Dunedin
Multidisciplinary Health and Development Research Unit, Zoology,
Nutrition, Psychology, Chemistry, Physiology and Marketing within
the University and the Department of Conservation and AgResearch
Ruakura outside the University.
The videos come with matching data sets (amended to ensure
anonymity where necessary). Given the new school mathematics
curriculum, there is need for software to analyse data, and a powerful,
free-to-use menu-driven schools version of the statistical package
GenStat has been developed to solve the problem. This is a major
advance in statistics education as GenStat software is used worldwide.
Usually expensive, the UK-based company VSN International who
control GenStat, responded positively to the request from John to
develop a free schools version of their software for New Zealand
schools. All school students can now access the software freely at
home once their school has registered.
The video clips and data sets come with lessons using GenStat
Schools and all of the resources are available from the department’s
website www.maths.otago.ac.nz/videos/statistics
A school can apply for a free GenStat Schools license at
www.vsni.co.uk/software/genstat-teaching
CONTACT:
Rose Newburn
Marketing – Communications
Division of Sciences
University of Otago
PO Box 56
Dunedin 9054
Email [email protected]
www.sciences.otago.ac.nz
Division of Sciences
www.otago.ac.nz/sciences
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