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 »

Conservation hypocrisy

28 05 2013

Another soul-searching post from Alejandro Frid.

Confession time. This is going to be delicate, and might even ruffle some big feathers. Still, all of us need to talk about it. In fact, I want to trigger a wide conversation on the flaws and merits of what I did.

Back in March of this year I saw a posting for a job with the Smithsonian Conservation Biology Institute (SCBI) seeking a ‘conservation biologist to provide expert advice in the design and implementation of a Biodiversity Monitoring and Assessment Program (BMAP) in northern British Columbia, Canada’. The job sounded cool and important. I was suited for it, knew northern British Columbia well, and loved the idea of working there.

But there was a catch. The job was focused on the local impacts of fossil fuel infrastructure while dissociating itself from the climate impacts of burning that fuel, and involved collaborating with the fossil fuel company. According to the posting, this was not a new thing for the Smithsonian:

Guided by the principles of the Convention on Biological Diversity, SCBI works with a selected group of oil and gas companies since 1996 to develop models designed to achieve conservation and sustainable development objectives while also protecting and conserving biodiversity, and maintaining vital ecosystem services that benefit both humans and wildlife.

Given that climate change already is diminishing global biodiversity and hampering the ecosystem services on which we all depend, the logic seemed inconsistent to me. But there was little time to ponder it. The application deadline had just passed and my soft-money position with the Vancouver Aquarium Marine Science Centre was fizzling out. So I applied, hastily, figuring that I would deal with the issue later, if they ever got back to me. Read the rest of this entry »

Who’s your carbon daddy?

20 04 2011

The other day, Bill Laurance asked Barry Brook and me to comment on an opinion editorial he was doing up, so I feel fully justified in reproducing it here (and he asked me to ;-). It has just been published online in Australian Geographic.

I hate to be the bearer of bad news, but here it is: China is now the biggest global emitter of carbon dioxide (CO2), the chief greenhouse gas – and Australia has helped it attain that dubious honour.

China now spews out about 6.5 billion tons of CO2 annually, whereas the USA emits 5.8 billion tons a year (based on data for 2008 compiled by the U.S. Department of Energy). Collectively, these two countries account for over 40 per cent of global CO2 emissions. Number three on the list is Russia, with 1.7 billion tons per year, followed closely by India.

Of course, China’s huge leap in emissions is largely down to its dramatic industrial and economic growth, in concert with the fact that it is the world’s most populous nation, with over 1.3 billion people. To help fuel its growth, China is now building nearly one new coal-fired power-generating plant per week. Read the rest of this entry »