Chasing Nematodes

A few days ago, I watched an incredible documentary called “Chasing Ice”. At first, I was a bit skeptical, thinking that itChasing_Ice_poster was likely going to be another tedious, statistics-riddled documentary about climate change. But James Balog, the director/photographer/instigator of the film, took a decidedly different approach by setting up cameras around the world (primarily in Greenland, Iceland, Alaska) and showing us the time-lapse photos of glaciers during a period of about five years. For many people, the idea of climate change is an understandably abstract concept, but when you see the frenetic pace of change within these glaciers, it becomes uncomfortably real.

In a similar vein, I think human-caused destruction of the oceans is a nebulous concept, particularly for people who either don’t have a relationship with the ocean or don’t have any ideas of how the ocean used to be. As a first-time scuba-diver back in 2010, I was blown away by the ostensibly vibrant life on Roatán’s reefs. But I was informed that things have changed, and the reef surrounding Roatán has been altered beyond recognition for those who used to dive here back in the 80’s and 90’s. Despite that knowledge, I still can’t imagine it; I still don’t have a comparable framework; I still don’t have any picture in my mind. This knowledge affects me, but it doesn’t haunt me. Balog’s images do, and that is precisely the power of photography and the documentation of visual change through time. Not to say that statistics and straight-up facts aren’t influential (they certainly are), but humans are emotional creatures: we remember things because of the way we felt, not because of what was said or done. This is why I think science, particularly science that influences policy, must not only focus on research methodology, but also take into consideration a visually compelling medium to communicate results. If we are to understand the declining state of the ocean, we must be shown, not told.

When I first typed into Google “deep sea” and “climate change”, I was not expecting to find much. And there wasn’t much. Why? Because it’s really difficult and expensive to try and quantify climate change thousands of feet below the surface of the ocean. There’s also the question of causality – the term “climate change” includes a broad range of effects: ocean acidification (caused by ocean uptake of anthropogenic CO2), increasing surface temperatures, salinity, changes in currents, and more. Also, studying climate change in the deep sea requires a small(ish) area of water that has experienced recent surface temperatures increases. Luckily, this happened in The Not-Too-Deep Mediterranean a few decades ago, and some scientists jumped on the opportunity to measure the deepsea ecosystem response.

Deepsea Nematode

Deepsea Nematode from http://www.nhm.ac.uk/

A dash of expensive sampling equipment, a teaspoon of highly complicated algorithms, and a half-cup of convoluted laboratory techniques plus a few handful of nematodes (aka worms), and you’ve got yourself a deep sea climate change study. Nematodes make up between 70-90% of benthic invertebrates and act like a canary in the coal mine, so they’re a great metric for ecosystem responses (bacterial density and carbon:nitrogen ratios are helpful, too). This study found major disturbances in availability of organic matter (an important food source for bottom-dwellers), benthic invertebrates, and bacterial density. All of this because of an increase in surface temperature of a few degrees! A similar response has been found in other deep sea habitats, where community structure was appreciably altered by natural El Nino/La Nina events.

The deepsea is beginning to emerge as a fragile and alarmingly sensitive environment. And it makes sense: environmental stability is a hallmark of the deepsea –  not many noteworthy disturbances occur (unless you’re one of the unlucky clams living near a black smoker on a mid-ocean ridge). So when atmospheric CO2 increases, it produces a cascade of effects which causes destructive disturbances that most deepsea denizens are not adequately prepared for. It’s a bit frightening to think that we may already be destroying and wiping out species that we never even knew in the first place.

Sources:

Danovaro R, Dell’Anno A, Fabiano M, Pusceddu A, Tselepides A (2001) Deep-sea ecosystem response to climate changes: the eastern Mediterranean case study. TRENDS in Ecology and Evolution 16(9): 505-510.

Ruhl HA, Smith KL (2004) Shift in Deep-Sea Community Structure Linked to Climate and Food Supply. Science 305: 513-515.

Smith KL, Ruhl HA, Bett BJ, Billett DSM, Lampitt RS, Kaufmann RS (2009) Climate, carbon cycling, and deep-ocean ecosystems. PNAS 106 (46):19211-19218

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~ by twonakedapes on June 17, 2013.

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