Climate experience makes some corals more resistant to heat stress

Preserving coral reefs, and everything they provide to communities across the tropics, on a warming planet will require identifying what might make a coral less susceptible to heat stress.

One of the big questions being studied by a number of scientists in the community is whether past temperature experience can make individual corals (by individual acclimation or adaptation) or coral communities (by selecting for tougher species) more resistant or more resilient to heat stress. I've been leading field projects in the Gilbert Islands of Kiribati, where this whimsical coral can be found, because the unique El Nino-driven climate provides a great natural laboratory for studying that big question.

In the lastest publication on this research, my colleagues Jessica Carilli (the lead author), Aaron Hartmann and I describe how massive corals on the atolls which naturally experience more frequent heat stress appear to have been more resistant to the recent El Nino-driven ocean heat waves. For an accessible summary of our findings, I recommend listening to this past weekend's episode of CBC Radio's Quirks and Quarks. But you can also read the paper itself: the journal PLoS-One is online and open access to all.

The research involved drilling coral cores, Jess Carilli's area of expertise, from sites around three different atolls, followed by some exhaustive lab analysis by my colleagues. The logistics of collecting the samples from the outer islands was unbelievably complicated, even for someone who knows the challenges of working in a remote island country. Just getting all the gear to Butaritari (that's the seat beside my flip-seat on the plane), making it all work and bringing the samples back intact will probably go down as our greatest accomplishment in science. We owe a huge thanks to local colleagues Aranteiti Tekiau, Toaea Beiateuea, Iobi Arabua and the late Moiwa Erutarem, who sadly was lost at sea six months after our expedition.

In the month of May, I'll be fundraising for the in-country expenses of a planned, future expedition through the second Scifund crowd-sourcing science funding campaign. By sheer coincidence I will actually be in Kiribati during some coral monitoring during most of the Scifund campaign. I'll try to put trip updates on Maribo whenever I find internet access.

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El Nino and the likelihood of mass coral bleaching

The seasonal forecasting system recently developed by NOAA Coral Reef Watch suggests that coral reefs in the Caribbean and in part of the central equatorial Pacific (the Line Islands, including Kiritimati or "Christmas Island") are at risk of coral bleaching in the coming months due to warm ocean temperatures. The forecast is due to the seeming return of El Nino in the Pacific.

The word from the NOAA Climate Prediction Center is that El Nino conditions are expected to prevail though the winter. Climate buffs can "see" the El Nino development in maps of sea surface temperature anomalies (warm water in the central and eastern Pacific) the thermocline (deepening in the eastern Pacific, meaning less upwelling off of South America) and sea surface height (the wind reversal on the equator means higher water in the central and eastern Pacific).

Not all El Nino events are created equal, and the models currently disagree on the current trajectory. This is especially important to remember when predicting the effect that El Nino conditions may have on other parts of the planet, what we luddites call "teleconnections". For example, a terrific paper by Kim et al. in Science demonstrated clear differences between the effect of "central pacific warming" and "eastern pacific warming" - which can both be classified as an El Nino event, depending what metric is applied - on ocean temperatures and hurricane tracks in the Caribbean.

One silver lining: For people living in the central Pacific, especially the parched islands of the southern Gilberts (Kiribati) Islands like Arorae, the development of El Nino conditions hopefully also means an end to the two-year drought that has claimed many of the coconut trees.

UPDATE: More on the Caribbean bleaching threat here

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Re-opening: Climate change and Kiribati

The name of this blog is a local word that was once used to describes the waves on the outer reed in Tarawa, the capital of the equatorial island nation of Kiribati. Tarawa and the other 32 islands of Kiribati are coral atolls, low-lying circular chains of islands created entirely by corals.

An atoll is created by corals growing along the slopes of a sinking old oceanic volcano, a fascinating idea proposed by Charles Darwin during his famous voyages across the Pacific that was not actually confirmed until US scientists started drilling (and testing bombs) in the Marshall Islands in the 1950s. In short, the reef maintains itself near sea level, sand starts to collect, some seeds blow in, and you end up with a malleable ring of flat, narrow islands of sand, coral rock and a few trees all surrounding a shallow lagoon.

The islands in a developed atoll like Tarawa or others in Kiribati is protected - partly - from the erosive action of open ocean waves by a fringing or "outer" reef. When you visit a populated, claustorphobic atoll like Tarawa, you spend a lot of time looking at those waves and wondering about the future. That's why I called the blog Maribo.

Maribo's been on hiatus for six weeks while I was conducting field work in the namesake nation of Kiribati. Over the next few weeks, in addition to some of the usual news items, Maribo will feature stories about the reality - and the unreality - about climate change in what people assume is one of the most vulnerable places on the planet.

What's really happening in Kiribati? Is there evidence for sea level rise? Are other threats more prominent than climate change? What do the local people think? What can be done to help a low-lying nation cope with climate change? Stay tuned.

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A long overdue clean-up in the Pacific

The LA Times ran this nice story about WWII veteran Leon Cooper who has been lobbying the US government to clean up the polluted beaches of the Tarawa, the site of bloody battle in 1943, and now the capital of Kiribati.

I spoke with the Times reporter about the causes of pollution on the crowded atoll and offered some graphic descriptions of beaches ("civilization after the apocalypse", the most extreme statement always makes it in the story, c'est la vie).

The beaches in the southern half of Tarawa, where the battle was fought, and where nearly half of all the i-Kiribati live, are not a pretty sight. For a detailed description an photos of Tarawa, check the dispatches on my home page.

Now, before condemning the i-Kiribati for polluting their backyard, and the site of a bloody WWII battle, it's worth asking how the problem evolved.

The i-Kiribati's traditional waste management system, like that of all indigenous groups in the Pacific, was simple but effective. All the waste, human and otherwise, was organic. It was swept under the coconut trees, where it regenerated the soil, or it was, ahem, deposited on the beach below the high tide line. Go there today , and you will still see people sweeping the ground in front of their huts like in the old days.

But two things changed. First, the influx of packaged goods meant that not all the garbage would biodegrade (in our lifetime). Second, the shift from subsistence living to a cash economy caused migration of people from the outer islands to Tarawa, the capital, and the only place with paying jobs. And more people means more human waste, all concentrated on a narrow atoll. The nutrient pollution from all the waste has degraded the already small supply of groundwater. This then caused a serious human health crisis.

This story is not unique to Tarawa. It is happening all over the Pacific, all over the tropics, all over the world, really, as communities switch from their indigenous lifestyle to a part, albeit a small one in this case, of the global economy.

The good news here is that the new recycling program has dramatically cut plastic and glass waste. And just maybe, the US government will respond to Mr. Cooper's earnest pleas to clean up Red Beach 1 and 2?

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Should Australia be worried about climate refugees?

A new study sponsored by a group of NGOs in collaboration with CSIRO - the Australian science agency - states that Australia should prepare for the regional economic and national security fallout from climate change. A primary concern is providing refuge the possibility of hundreds of thousands or millions of "environmental refugees" from low-lying countries in south Asia and the Pacific. Unlike Australia, New Zealand has already reached agreement with Kiribati, Tuvalu and other Pacific nations to accept people displaced by environmental degradation or climate change. Here's the transcript of a short ABC (the other ABC) interview with one of the study authors.

I've not been able to locate a copy of the study (Australia Responds: Helping Our Neighbours Fight Climate Change) itself - if you find one, let me know.

Australia joined the US as a pariah in the eyes of advocates for international action on climate change when, under PM John Howard, it chose not to sign the Kyoto Protocol. The irony is that Australia had negotiated the right to increase GHG emissions by 8% over 1990 levels (by 2008-2012) under the Kyoto Protocol, and may actually be on pace to meet that commitment despite not signing the agreement.

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