Latest research stories
Can mirror imaging fool the brain? - Liz Franz and Ranjan Debnath
LiDARRAS digging into our history, surveying our heritage - Pascal Sirguey, Richard Hemi, Chris Page
SMART grid, green power - Michael Jack
Exploring the Ross Ice Shelf - Christina Hulbe, Christian Ohneiser, Andrew Gorman, Greg Leonard
Rock and ice deformations Dave Prior
Hoea te Waka, Piki te Mātau Anne-Marie Jackson, Sally Carson
Comparing apples with apples Valentina Ting
Large-scale 3D models from images Steven Mills, Zhiyi Huang and David Eyers
Eruptive geology at Cape Wanbrow Ben Moorhouse
Sediment cores in the subantarctic Chris Moy
Trace elements in the ocean Rob Middag
Leaf phenology Steven Higgins
Magnetometers Christian Ohneiser and Sally Brooker
Coral-eating seastars Miles Lamare
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Geology PhD student Jack Williams explains: "The Deep Fault Drilling Project phase 2 (DFDP-2) aims to sample the Alpine Fault that runs along the West Coast of South Island at a depth of ~1000 m. The drill site is based in Whataroa Valley, about 30 km north of Franz Josef where we’re currently at a depth of about 350 m (as of 00:00 on 22nd October). This has involved drilling through a 240 m thick sequence of recent (Quaternary) sediments during which we have already made some surprising scientific discoveries!
A new drill rig is in place that's designed to drill through the hard schist bedrock that we expect to encounter most of the way to intercepting the Alpine Fault itself. Drilling is proceeding smoothly, 24 hours a day come rain or shine, at a rate of about 2-3 m/hour; we hope to reach the fault in mid-November. With drilling going smoothly morale is currently high amongst the 50 or so strong science team comprising researchers from New Zealand and much further afield. When not on shift the team are making use of the great (and not so great) weather to venture to field exposures of the Alpine Fault and some of the stunning scenery around the West Coast.
The project is being jointly led by GNS Science, Victoria University of Wellington, and the University of Otago and is funded mainly by the International Continental Scientific Drilling Program, the Marsden Fund of the Royal Society of New Zealand, and the participating scientists’ own organisations. It involves scientists from New Zealand organisations and from more than a dozen other countries. (photo by Dave Prior)
Russell Bissett wins 2014 Hatherton Award
Dr Russell Bisset, formerly of the University of Otago but now doing a postdoc in the United States, has been awarded the 2014 Hatherton Award by the Royal Society of New Zealand, for his paper “Fingerprinting Rotons in a Dipolar Condensate: Super-Poissonian Peak in the Atom-Number Fluctuations” by R. N. Bisset and P. B. Blakie, Physical Review Letters 110, 265302 (2013). The award is for the best scientific paper by a student registered for the degree of PhD in Physical Sciences, Earth Sciences and Mathematical and Information Sciences at a New Zealand university.
This paper presents a new theory for the behaviour of condensates in which exotic “roton” excitations develop. These excitations were first predicted to occur in this system more than 10 years ago, but have yet to be observed in experiments. With the rapid developments made in experiments in the past two years, a vigorous race has developed to find these excitations. Russell’s work has discovered a striking feature of the rotons that has been welcomed by the field as a smoking gun for proving their existence. Furthermore, this theory provides fundamental insight into the underlying properties of these excitations, and shows that the precise way that measurements are made can reveal important details about the rotons, like where they “live” in the condensate, and what size they are.
Monique Francois (Masters) and Associate Professor Jim Cotter of the School of Physical Education, Sport and Exercise Sciences have recently published results of their research into effective control of blood glucose for people suffering from insulin resistance , a precursor to type 2 diabetes.
Monique says : “We found exercise snacking before meals to be a novel and effective approach to improve blood sugar control in individuals with insulin resistance. Brief, intense interval exercise bouts undertaken immediately before breakfast, lunch and dinner had a greater impact on post-meal and subsequent 24 h glucose concentrations than did a single bout of moderate, continuous exercise undertaken before dinner.
The practical implications of our findings are that, for individuals who are insulin resistant and who experience marked post-meal increases in blood glucose, both the timing and the intensity of exercise should be considered for optimising glucose control.” The research has close associations with the MoveMe programme in Dunedin.
For fruit growers, it is crucial to understand how plant disease spreads through an orchard. In order to do so, however, the growers face a problem: they depend on the orchard for their livelihood. while scientists would like to leave the disease unchecked so the spread can be observed.
To address this problem, a set of modelling tools has been developed that factors in control measures being taken against an emerging plant epidemic.
These modelling tools have been announced this week in the Proceedings of the National Academy of Sciences (USA), in a paper whose lead author is Dr Matthew Parry of the University of Otago's Department of Mathematics & Statistics.
The research is based on a long-term study of a Florida citrus orchard infected with the disease Huanglongbing, which is spread by a small winged insect known as the Asian citrus psyllid. The approach of Parry and his co-authors is innovative because it takes into account control measures such as spraying to kill off the psyllid and removal of diseased trees. Their model also takes note of the way a tree's age affects its response to the disease and how this response changes throughout the year.
Armed with the results of their study, the researchers next intend to work with growers to test alternative control methods virtually. In this way, they aim to find the most efficient and cost-effective control measures for Huanglongbing.
Parry says it should be possible to use these tools in New Zealand contexts. The researchers are already discussing potential applications with Plant & Food Research and the Bio-Protection Research Centre.
Open grassland with a scattering of trees is called savanna – it’s a savanna in Africa, a savanna in Latin America, and a savanna in Australia. A classification like this makes sense of bio-geographical areas that have similarities, but recent research shows that focusing on these similarities won’t produce useful models for predicting climate change impacts .
Professor Steve Higgins from Botany is co-author on a paper recently released in Science; he and his colleagues analysed data from more than 2000 sites in savannas in South America, Australia and Africa. They found that although four main impact factors – moisture availability, fire, soil-type and temperature, shape all savannas, the impact of these factors is not uniform across all.
Higgins says “ This paper forces us to realise we can no longer assume that similar looking vegetation will respond in the same way to climate change. This in turn means we have to rethink how we represent the world’s vegetation in models used to predict climate change impacts.”
At the moment scientists represent vegetation in global climate change impact models using structurally similar vegetation units, which they call biomes. Doing this makes modelling the impact of climate change much more straightforward! In savannas for example, there is carbon storage by vegetation, but also fire which releases carbon into the atmosphere. Modelling the balance between these two is now further complicated by this finding which suggests that savannas in Africa, South America and Australia behave in their own distinctive ways.
Steve Higgins says this has been a fun project, but has had its challenges… “we used data provided by other researchers. While this gave us an amazing data set, the process of ensuring that the data - collected by different people for different purposes - was suitable for our study was time consuming and challenging. But we learnt a lot from one another and the results vindicate all the effort ”
This work demonstrates clearly that each savanna responds differently to the four key factors of fire, temperature, soils and moisture availability so essentially each case is a Special Case… but if every case is a special case, how can any useful models be developed?
“We are in the process of developing new models that reflect the role of evolutionary history in shaping why for example Australian and African savannas behave so differently despite some apparent similarities. Perhaps an analogy can be made here with weather predictions – the better a climate model can describe the current conditions the further into the future it can forecast – we believe that the better we can describe how evolutionary history got us to our current situation, the better we will be able to forecast future vegetation.”
The article appeared in the Science journal at the end of January, and the research was supported by funding from the Australian Research council and the Royal Society of New Zealand
An ophiolite belt - a stretch of mantle rock from below the Earth’s crust - stretches from Balclutha to Nelson. It's exposed from Balclutha to Gore, intersects the Alpine Fault through the Cascade River valley, and then on up to Nelson north of Lake St Arnaud. The outcrop from there through to Dun Mountain is probably the best place in the world to source dunite - mantle rock that's been pushed up to the earth's surface by tectonic movement. Dunite is the second most dense rock on the earth’s surface – you find this out when you lift a piece!
The rock and surrounding dirt are so full of iron that few things will grow - the bald Red Hills are clearly visible from the air. Most of the dunite around the world that’s exposed at the surface has interacted with seawater and atmosphere to become serpentine but at the Red Hills there's 125 km2 that’s NOT metamorphosed into serpentine, an excellent tool to research the tectonic processes involved in the creation of mantle rock. The area has been the focus of international research for some time.
Dr Virginia Toy in Geology is a part of that research. "One focus for this research is that it's reaction with CO2 that changes dunite into serpentine. So researchers want to see whether it’s possible to use that mechanism to sequester CO2 permanently. Researchers are also fascinated by the contribution this rock type may have made to the beginning of life on earth. Springs coming through this kind of rock are basic (as opposed to acid), and it’s thought that proto-life forms consumed the hydrogen ions in the water.”
So how does an American researcher obtain dunite for work in their research Lab? Sometimes the researchers travel to Nelson to collect it, and sometimes they phone a friend….
“So Wen-Lu Zhong in the US wants some dunite to experiment on – she wants to use compression and deformation machines to explore the processes that create this kind of rock. She asked me, and I asked some Texan researchers who were going in to the Red Hills over summer. They helicoptered out a big chunk, and delivered it to an ex-Geology staff member in Nelson. Then someone knew someone else was travelling through with a small station wagon, so they brought it to Otago. We’ll drill cores (diameter of a 20c piece) and send those to Wen-Lu”.
Having travelled from below the earth’s crust, some very small pieces of the mantle will travel an even longer distance.
There are unknown numbers of different cyanobacteria – in the soil, in fresh water and in the sea. Simple organisms that capture sunlight for their energy supply via photosynthesis: the perfect “lab rat” of the plant biochemistry lab.
As well as harvesting energy for themselves, cyanobacteria produce hydrogen and small amounts of ethanol and in these energy-conscious times these ubiquitous energy factories are of particular interest to us. Tina Summerfield of the Botany department has been working on cyanobacteria and their photosynthesis processes for some time, investigating which strains of cyanobacteria are the highest producers of hydrogen.
“There’s a balancing act between oxygen production through photosynthesis and the production of hydrogen. Oxygen inhibits the enzyme that generates hydrogen, but both are products of photosynthesis. So there’s a tipping point where more oxygen is produced, cutting off the production of hydrogen. This varies from one strain to another. “
While working on this Tina found something extraordinary: one strain had a different response, producing alternative forms of key proteins in photosynthesis.
“These alternative proteins are increased under low oxygen conditions, we will investigate how they alter photosynthetic performance and whether this alters the ability of the cyanobacterium to produce hydrogen. These changes may enable the hydrogen production to continue for longer.”
The other puzzle is the enzyme itself, hydrogenase, which produces hydrogen but also consumes it. Summerfield is exploring what triggers this switch as well.
“ There are so many different kinds of cyanobacteria, and they do different things – some produce hydrogen, some fix nitrogen; there’s so much metabolic potential in the different varieties. The ones that live in hot springs would be very interesting to explore…”
At present Summerfield is working on one of the more commonly used “lab rat” strains, but investigating others around NZ is a part of future work.