Noses baffled by ocean acidification

18 04 2017

Clown fish couple (Amphiprion percula) among the tentacles of anemone Heteractis magnifica in Kimbe Bay (Papua New Guinea) – courtesy of Mark McCormick. Clownfish protect anemones from predators and parasites in exchange of shelter and food. The fish tolerates the host’s venom because its skin is protected by a mucus layer some 2-3× thicker than phylogenetically related species (12); clownfish fabricate the mucus themselves and seem to obtain anemone antigens through a period of acclimation (13), but whether protection is acquired or innate is still debated. Clownfish are highly social bony fish, forming groups with one reproductive pair (up to 11 cm in length each) and several smaller, non-reproductive males. Reproduction is protandrous (also known as sequential hermaphroditism), so larvae are born male and, as soon as the reproductive female dies, her widower becomes female and the largest of the subsidiary males becomes the alpha male. The IUCN lists clownfish, generically named ‘anemone fish’, as threatened by the pet-trade industry and habitat degradation, although surprisingly, only 1 species has been assessed (A. sandaracinos). The clown anemone fish A. ocellaris is the species that inspired Nemo in the 2003 Academy-Award fiction movie – contrary to the logical expectation that the Oscars Red Carpet would generate support for conservation on behalf of Hollywood, of the 1568 species represented in the movie, only 16 % of those evaluated are threatened (14).

Smell is like noise, the more scents we breathe in one sniff, the more difficult it is to distinguish them to the point of olfactory saturation. Experimental work with clownfish reveals that the increase in dissolved carbon dioxide in seawater, mimicking ocean acidification, alters olfactory physiology, with potential cascading effects on the demography of species.

Places such as a restaurant, a hospital or a library have a characteristic bouquet, and we can guess the emotional state of other people by their scents. Smell is critical between predators and prey of many species because both have evolved to detect each other without the aid of vision. At sea, the smell of predators dissolves in water during detection, attack, capture, and ingestion of prey, and many fishes use this information to assess the risk of ending up crunched by enemy teeth (1, 2). But predator-prey interactions can be modified by changes in the chemical composition of seawater and are therefore highly sensitive to ongoing ocean acidification (see global measuring network here). Experts regard ocean acidification as the ‘other CO2 problem’ of climate change (3) — just to emphasize that anthropogenic climate-change impacts terrestrial and aquatic ecosystems alike. Acidification occurs because the ocean absorbs CO2 at a rate proportional with the concentration of this gas in the atmosphere and, once dissolved, CO2 becomes carbonic acid (H2CO3), which in turn releases protons (H+) — in simple terms, pH is the concentration of protons (see video about ocean acidification): Read the rest of this entry »

Not 100% renewable, but 0% carbon

5 04 2017

635906686103388841-366754148_perfection1Anyone familiar with this blog and our work on energy issues will not be surprised by my sincere support of nuclear power as the only realistic solution to climate change in the electricity (and possibly transport and industrial heat) arena. I’ve laid my cards on the table in the peer-reviewed literature (e.g., see here, here, here, here, here & here) and the standard media, and I’ve even joined the board of a new environmental NGO that supports nuclear.

And there is hope, despite the ever-increasing human population, rising consumerism, dwindling resources, and the ubiquity of ideologically driven and ethically compromised politicians. I am hopeful for several reasons, including rising safety and reliability standards of modern nuclear technology, the continued momentum of building new fission reactors in many countries, and even the beginnings of real conversations about nuclear power (or at least, the first steps toward this) in countries where nuclear energy is currently banned (e.g., Australia). I’m also heartened by the fact that nearly every conservation scientists with whom I speak is generally supportive, or at least non-resistant, to the idea of nuclear power as part of the climate change solution. An open letter by our colleagues attests to this. In fact, every day that passes brings new evidence that we cannot ignore this solution any longer.

Even despite the evidence in support of implementing a strong nuclear component into climate change-mitigation strategies, one of the most frequent arguments for not doing so is that society can achieve all of its energy needs and simultaneously combat climate change by constructing 100% renewable-energy pathways. While it is an easy mantra to repeat because it feels right intrinsically to nearly everyone with an environmental conscience, as a scientist I also had to ask if such a monumental task is even technically feasible. Read the rest of this entry »

Not all wetlands are created equal

13 02 2017

little-guyLast year I wrote what has become a highly viewed post here at about the plight of the world’s freshwater biodiversity. In a word, it’s ‘buggered’.

But there are steps we can take to avoid losing even more of that precious freshwater biodiversity. The first, of course, is to stop sucking all the water out of our streams and wetlands. With a global population of 7.5 billion people and climbing, the competition for freshwater will usually mean that non-human life forms lose that race. However, the more people (and those making the decisions, in particular) realise that intact wetlands do us more good as wetlands rather than carparks, housing developments, or farmland (via freshwater filtering, species protection, carbon storage, etc.), the more we have a chance to save them.

My former MSc student, the very clever David Deane1, has been working tirelessly to examine different scenarios of wetland plant biodiversity change in South Australia, and is now the proud lead author of a corker of a new paper in Biological Conservation. Having already published one paper about how wetland plant biodiversity patterns are driven by rare terrestrial plants, his latest is a very important contribution about how to manage our precious wetlands. Read the rest of this entry »

Boreal forest on the edge of a climate-change tipping point

15 11 2016

As some know, I dabble a bit in the carbon affairs of the boreal zone, and so when writer Christine Ottery interviewed me about the topic, I felt compelled to reproduce her article here (originally published on EnergyDesk).

A view of the Waswanipi-Broadback Forest in the Abitibi region of Northern Quebec, one of the last remaining intact Boreal Forests in the province (source: EnergyDesk).

A view of the Waswanipi-Broadback forest in the Abitibi region of northern Quebec, one of the last remaining intact boreal forests in the Canadian province (source: EnergyDesk).

The boreal forest encircles the Earth around and just below the Arctic Circle like a big carbon-storing hug. It can mostly be found covering large swathes of Russia, Canada and Alaska, and some Scandinavian countries.

In fact, the boreal – sometimes called by its Russian name ‘taiga’ or ‘Great Northern Forest’ – is perhaps the biggest terrestrial carbon store in the world.

So it’s important to protect in a world where we’re aiming for 1.5 or – at worst – under two degrees celsius of global warming.

“Our capacity to limit average global warming to less than 2 degrees is already highly improbable, so every possible mechanism to reduce emissions must be employed as early as possible. Maintaining and recovering our forests is part of that solution,” Professor Corey Bradshaw, a leading researcher into boreal forests based at the University of Adelaide, told Energydesk.

It’s not that tropical rainforests aren’t important, but recent research led by Bradshaw published in Global and Planetary Change shows that that there is more carbon held in the boreal forests than previously realised.

But there’s a problem. Read the rest of this entry »

Inexorable rise of human population pressures in Africa

31 08 2016
© Nick Brandt

© Nick Brandt

I’ve been a bit mad preparing for an upcoming conference, so I haven’t had a lot of time lately to blog about interesting developments in the conservation world. However, it struck me today that my preparations provide ideal material for a post about the future of Africa’s biodiversity.

I’ve been lucky enough to be invited to the University of Pretoria Mammal Research Unit‘s 50th Anniversary Celebration conference to be held from 12-16 September this year in Kruger National Park. Not only will this be my first time to Africa (I know — it has taken me far too long), the conference will itself be in one of the world’s best-known protected areas.

While decidedly fortunate to be invited, I am a bit intimidated by the line-up of big brains that will be attending, and of the fact that I know next to bugger all about African mammals (in a conservation science sense, of course). Still, apparently my insight as an outsider and ‘global’ thinker might be useful, so I’ve been hard at it the last few weeks planning my talk and doing some rather interesting analyses. I want to share some of these with you now beforehand, although I won’t likely give away the big prize until after I return to Australia.

I’ve been asked to talk about human population pressures on (southern) African mammal species, which might seem simple enough until you start to delve into the complexities of just how human populations affect wildlife. It’s simply from the perspective that human changes to the environment (e.g., deforestation, agricultural expansion, hunting, climate change, etc.) do cause species to dwindle and become extinct faster than they otherwise would (hence the entire field of conservation science). However, it’s another thing entirely to attempt to predict what might happen decades or centuries down the track. Read the rest of this entry »

Keeping India’s forests

9 08 2016

I’ve just returned from a short trip to the National Centre for Biological Sciences (NCBS) in Bangalore, Karnataka, one of India’s elite biological research institutes.

Panorama of a forested landscape (Savandurga monolith in the background) just south of Bangalore, Karnataka (photo: CJA Bradshaw)

Panorama of a forested landscape (Savandurga monolith in the background) just south of Bangalore, Karnataka (photo: CJA Bradshaw)

I was invited to give a series of seminars (you can see the titles here), and hopefully establish some new collaborations. My wonderful hosts, Deepa Agashe & Jayashree Ratnam, made sure I was busy meeting nearly everyone I could in ecology and evolution, and I’m happy to say that collaborations have begun. I also think NCBS will be a wonderful conduit for future students coming to Australia.

It was my first time visiting India1, and I admit that I had many preconceptions about the country that were probably unfounded. Don’t get me wrong — many of them were spot on, such as the glorious food (I particularly liked the southern India cuisine of dhosa, iddly & the various fruit-flavoured semolina concoctions), the insanity of urban traffic, the juxtaposition of extreme wealth and extreme poverty, and the politeness of Indian society (Indians have to be some of the politest people on the planet).

But where I probably was most at fault of making incorrect assumptions was regarding the state of India’s natural ecosystems, and in particular its native forests and grasslands. Read the rest of this entry »