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Revisiting the earthquake-uplifted coast, New Zealand

We have returned to the uplifted areas along the Canterbury coast, north of Kaikoura, a few times in the 22 months since the large earthquakes raised the seabed by up to six metres, decimating local marine communities (see previous blog post, here). In April this year we were excited to find a couple of young, newly-settled buoyant bull-kelp plants at places where these species had been totally wiped out. Last week, with the help of a drone and coastal boat surveys (a shout-out to Jordan from Clarence River Rafting for his amazing help!), we found several more at every site! Some of them are at least a year old, so must have hung in through several big storms.

So what does this mean?

In terms of post-quake recovery, it is great news! We already know from our surveys of washed-up kelp along the beaches that the ecologically-important bull-kelp is certainly able to drift to these areas, but the new, baby kelp plants show that offspring from those drifters can rapidly attach and start growing. It will probably only take a few years for the marine communities to become fairly strong, again.

Johnette Peters, an Honours student in my research group this year, has been using high-resolution genomic analyses (GBS) to work out exactly where those drift kelp plants have come from, which will tell us how far they have travelled.

We’re now hoping to get funding to use the same approach to find out whether the young kelp plants - and other marine organisms, such as snails - are genetically distinct from what was there before (we know the genetic signatures of what was there before, because we collected samples in the days straight after the quake). That will help us to understand how earthquakes, and other huge disturbances, help to structure spatial patterns of biodiversity, and particularly genetic diversity (see also previous post here).

Stay tuned!

Durvillaea antarctica drifting at sea near the most-uplifted part of the North Canterbury coast, in September 2018

The team for this research also includes:

Prof Jon Waters, University of Otago, New Zealand

Prof Dave Craw, University of Otago, New Zealand

Johnette Peters, research student, ANU

Elahe Parvizi, research student, University of Otago

…but we there could be many opportunities for other students to contribute, so get in touch with us if this research interests you!

We are also hugely grateful to student Sam Jarvis, who voluntarily collected many washed-up kelp samples for us throughout 2017. What a legend! And thanks to the several other residents of North Canterbury that have helped us during our research so far.

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