Our Changing World

Thursday 2 June 2011, with Alison Ballance, Ruth Beran & Veronika Meduna

Audio from Thursday 2 June 2011

Not all audio is available due to copyright restrictions.

  • Seismic Testing a Tectonic Plate Boundary ( 13′ 33″ )

    21:06 Seismic blasts across a tectonic plate boundary in the Wairarapa will help understand locked plates

  • Bryophytes ( 17′ 17″ )

    21:20 A bryophyte hunt on Mana Island is a chance to learn more about mosses, liverworts and hornworts

  • Why Cows Prefer to Graze at Dusk ( 7′ 45″ )

    21:34 Understanding how grass quality changes over time and when is the best time for cows to eat can help improve grazing management

  • Bioimprints ( 13′ 07″ )

    21:46 Scientists in Christchurch are taking imprints of cells in a UV curable polymer with implications for imaging and biocompability

On This Programme

Scanning the Plate Boundary

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Stuart Henrys, at GNS Science, prepares some of the seismic recorders for deployment in the field. (Image: Margaret Low, GNS Science)

In one of the biggest deployments of seismic equipment in New Zealand, geologists are scanning the structure of the tectonic plate boundary that runs deep below the lower North Island. The Pacific plate, to the east of the North Island, is being forced under the Australian plate but the giant slabs are not sliding past each other uniformly. Underneath Wellington, the plates are locked.

The team set up 900 seismic recorders along a transect from Kapiti Island to just east of Martinborough in the Wairarapa to record the echo of several explosions (500kg of dynamite each) which were detonated to mimic small earthquakes. The resulting three-dimensional image can be compared to a CAT scan of the Earth's crust.

Victoria University geophysicist Tim Stern and Stuart Henrys, at GNS Science, explain how the project will help them to describe the properties of the locked interface and how it might behave when it ruptures in an earthquake. You can find out more on GNS Science outreach educator Julian Thompson’s blog.

Bryophytes

Bryophyte

Rodney Lewington takes a close look at a liverwort through a hand lens, and a moss plant with spore-bearing sporophytes (photos: A. Ballance and P. Michel)

Alison Ballance joined moss expert Peter Beveridge and liverwort expert Rodney Lewington on a bryophyte hunt on Wellington’s Mana Island, as part of the Mana Bioblitz a couple of months ago. Bryophyte is an umbrella term for a group of small ancient plants – mosses, liverworts and hornworts. Only a single moss specimen had ever been collected from Mana Island before, and although the revegetating island is too dry and wind-exposed to be ‘perfect’ habitat for the moisture-loving plants, the team nonetheless managed to collect 43 species of moss, 33 species of liverworts and a single hornwort species.

bryophyte

The bryophyte team searching for liverworts on a damp shady bank (photo: P. Michel)

Why Cows Prefer to Graze at Dusk

Pablo Gregorini from Dairy New Zealand is part of a team working on optimising the amount of milk and meat that dairy cows produce. He explains to Alison Ballance that the quality of grass varies during the day, and that as a result cows get more nutritional value if they feed at dusk rather than at dawn. Understanding interactions such as this between plants, cows and the bugs in their rumen allows farmers to manage their herds to get the greatest returns from a set amount of grass.

Bioimprints

Bioimprints pano

From left to right: Volker Nock, Lynn Murray, John Evans, and Maan Alkaisi; and stained (blue) cells growing on a bioimprint surface

Developed at University of Canterbury and University of Otago, Christchurch, bioimprint technology replicates cellular surface features into a polymer mould. The resulting bioimprint can be used to take high resolution images or, more innovatively, to grow cells on a scaffold.

As Ruth Beran finds out, investigators Volker Nock, Lynn Murray, John Evans, and Maan Alkaisi are looking at variation in cell adhesion and the potential impact this surface modification tool may have on biomaterials and biological functioning. The research is currently being funded by a grant from the Marsden Fund, and the MacDiarmid Institute for Advanced Materials and Nanotechnology.

Next Week

Rip currents and how they develop; biocomposites; the link between women, protein and exercise; and a new process of denitrification occurring in lake sediments.