Climate Change and Our Oceans

Friday, April 1, 2011

What do we stand to lose?

It is often tempting to think of climate change as a global problem, something that doesn't directly affect us individually in our local area. As we carry out our daily routines, it’s easy to forget the vast impact our coastal location has on our lives. However, we live on an island, and therefore, we are intimately connected with the sea. On Friday, March 18th, I took to the skies around the greater Victoria area to get a top-down perspective on our current situation. Although I have lived here my whole life, and spent a considerable amount of time working on and playing in our local waters, I remain unremittingly in awe of the beauty that permeates the west coast of Canada. Even on a cloudy March day, I was no less amazed by the majesty of the landscape from the air as I passed over familiar landmarks: Cordova Bay, Discovery Island, Constance Bank, Oak Bay, the Gorge, Esquimalt Harbour, the Esquimalt Lagoon, Albert Head, Rocky Point, Race Rocks, Sooke Harbour, the Saanich inlet, Mt. Finlayson, and finally, Patricia Bay.

View Aerial Tour of Greater Victoria Coastline in a larger map

While observing from above, the profound impact that our human activities have on the local environment was made all the more salient. Indeed, our environment has changed significantly even in our lifetime. Glacier expert and UVic Scientist Dan Smith, in the Kamloops Daily News article, Vanishing Landscape on Oct 9, 2010, stated that of the 172 glaciers that were present on Vancouver Island in the 1970’s there are only 6 or 7 left. Another UVic scientist, Nancy Turner, in a 2009 article, interviewed the elders of local indigenous populations who have reported acute changes in their lifetimes and even more extreme changes in comparison to their oral histories. Having been forced to adapt since the arrival of the Europeans, first nations people have been resilient in their ability to adapt to their rapidly changing environment. However, recent declines in species populations, and the arrival of new species into the declining forests and grasslands have provided an unprecedented challenge. While we face consequences we have created and try to change our destructive ways, we could learn much from those who have inhabited and cared for this land and these waters for thousands of years. Flying low above the sprawling western communities, we turned over a clear cut swath of the Sooke foothills, which appeared to me like a great wound at the foot of the rising Gowlland range. As we descended into Finlayson Arm in our final approach, I became painfully aware of what is at stake if we, as individuals, and as a society continue our negligent abuse of the land and sea.

Sources

Turner, N., & Clifton, H., (2009). ‘‘It’s so different today’’: Climate change and indigenous lifeways in British Columbia, Global Climate Change, 19, 180-190.

Youds, M. (2010, Oct 9). Vanishing Landscape, Kamloops Daily News p. C.1.

Monday, March 28, 2011

Dissolving Shells

The world knows of the harmful effects anthropogenic CO2 has on our atmosphere, but few people know how harmful it can be to our oceans. When carbon dioxide is absorbed into sea water it increases the hydrogen ion concentration, and as a result, decreases the pH of the water, making it more acidic. Over a long time, the erosion of rocks from land into the oceans balances out the acidification, but because of the abnormal amount of CO2 humans are putting into the atmosphere the oceans are absorbing more CO2 than they can safely handle, resulting in a dangerous decrease in ocean pH. Just like our atmosphere, the oceans aren’t used to dealing with such a large influx of CO2 in such a short time period.

What does this mean for life in our oceans?

Scientists have found that within the next 90 years, if we continue to pump CO2 into the atmosphere at the same rate as we are now, the oceans will become too acidic to sustain many of its keystone species, such as those who rely on calcium carbonate shells to survive. These species will find it more and more difficult to produce their shells, in addition to maintaining their thickness and even form.

The majority of plankton species have a calcium carbonate shell component in at least one stage of their life. Plankton is at the bottom of the oceans food web. It starts with phytoplankton, which are eaten by zooplankton, which are then eaten by small fish and invertebrates, who are eaten by bigger fish and so on and so forth until we get to dolphins, whales and sharks which are at the top of the web. Without plankton, life in our oceans would be very different.

A recent National Geographic article looked at an ocean environment off the coast of Costello Aragonese, an island in the Tyrrhenian Sea that allows scientists to look at what the future holds for a CO2 saturated ocean. In the waters surrounding the island, CO2 arises from volcanic vents and dissolves into the water to form carbonic acid, mimicking what’s going on in the worlds oceans on a much faster timescale. At first the divers noticed an absence of barnacles along the waters’ edge and then limpet shells that were so thin that they were almost transparent. There were blades of sea grass without the regular creatures that normally encrust their surface, and an absence of sea urchins that were otherwise a norm outside the area.

View Costello Aragonese in a larger map

These waters are what the worlds’ oceans are forecasted to be like by the year 2100 if we don’t do something soon about our carbon emissions. It’s our responsibility to preserve our oceans so that future generations may have the fortune of a prosperous ocean, full of life and beauty.

Sources and Related Articles:

http://ngm.nationalgeographic.com/2011/04/ocean-acidification/kolbert-text/1

http://en.wikipedia.org/wiki/Ocean_acidification#Calcification

http://www.mbari.org/staff/oreilly/schoolPresentation/oceancolor/lifeWeb.html

http://www.youtube.com/watch?v=5cqCvcX7buo&feature=player_embedded#at=17

http://switchboard.nrdc.org/blogs/schasis/rapidly_changing_seas_ocean_ac.html

Monday, March 21, 2011

Sequestering Sea Stars

It seems as if “star” is an appropriate description for our Echinoderm heroin. It appears that Sea stars and their brethren, such as sea urchins and sea cucumbers are aiding our efforts to rid our atmosphere and oceans of the increasingly detestable carbon dioxide, according to a study done by Mario Lebrato from the Leibniz institute of marine science in Germany. He determined that in total they extract approximately 100 million tons of carbon from the atmosphere each year. But how do they do it?

If you’ve ever picked up a sea urchin or sea star you’ve noticed that they’re far from soft and cuddly. Sea urchins have those hard defensive spines that stick out like a giant billboard message to other sea creatures to stay away and don’t try to bite me because it’ll hurt. The urchin’s body, composed of several plates, supports the spines and is just as hard because it’s made up of the same stuff, calcium carbonate. You’ll find that a sea stars body is similar and even sea cucumbers utilize the structural integrity of calcium carbonate within its tissues.

The body of a sea urchin. The round cones protruding outward are where the spines normally sit and pivot around.

A dried up sea star, showing its calcareous skeleton.

An image of the ossicles that are present within the tissue of sea cucumbers.

Calcium carbonate is a chemical compound with the chemical formula CaCO₃ and is the main component in the shells of sea creatures like snails and clams. As Echinoderms grow they create more calcium carbonate. The carbon used in its composition comes from carbon dioxide residing in the sea water surrounding the echinoderm. This is how echinoderms are considered to aid in the decrease of carbon dioxide in our oceans. When they die, their bodies settle to the sea bottom and accumulate over time to form chalk, or limestone.