Monday, February 27, 2012

a porpoise for a trip

The picture of the turtle I took was
blurry - so here's my lunch instead
This morning I went on a short road trip to drop off a harbour porpoise and pick up an olive ridley sea turtle from the Pacific Biological Centre - a trip that took two hours one way. Both animals had been found dead, frozen and put into scientists hands.

Olive ridley’s are the most abundant of the sea turtles. Unfortunately, their numbers are declining putting them at risk of extinction like all the other sea turtles. Years ago, I saw a live one on a beach in Costa Rica that came ashore to lay eggs - we moved along quickly to avoid disturbing her. It was night and to me she seemed huge as she hauled her mass up the sandy beach, however, they’re small compared to other sea turtles.

The sea turtle we picked up today ventured too far north as they normally live in tropical waters - in fact, turtle was the first olive ridley ever found here. Cold blood in cold water meant the animal probably was moving pretty slow. It was found on a beach in Toffino after it was too late to help. Why it came this far north we don’t know.

I’ll write more about the turtle shortly, as I’ll be helping at the museum to preserve it.

Thursday, February 23, 2012

talks about climate change

I'm still at the Ocean Sciences Meeting. So far, every session of talks I attend are in rooms with a capacity for a great number more people than show up. As I look around, there is always an uneven sprinkling of people throughout the room.

Wednesday, 22 February 2012 - Day 3

An interesting point came up that I hadn’t considered: coral reefs are studied with much more frequency than the equally (or more so) common eelgrass beds. I wonder if the colourful fish make are simply more appealing? Although, fascinating creatures live in eelgrass.

One of the sessions I attended was titled ‘Imaging the Ocean Interior’ - I was excited about one of the last talks that hinted at exploring underwater ice caverns with acoustics. Two of these talks focused on re-using the seismic survey data collected by oil and gas companies. This is data collected to look at what is beneath the ocean floor, but it can provides interesting information about the structure within the water column such as internal waves and boundaries between layers.

A cool use of acoustics is looking at really small things. One group is able to ‘see’ targets down to 0.8 mm in size. This same group has simultaneously developed an optical system, essentially an underwater microscope, that sees to 25 micrometers giving a clear view of phytoplankton. Both these techniques can be deployed into the ocean, reducing the need to bring samples back to the lab.

The afternoon wasn’t without disappointment. The under ice exploring talk focused on a project they wanted to do, not one already completed. I’ll have to attend the next conference to see their results.

Thursday, 23 February 2012 - Day 4

Melting glaciers are an iconic symbol of climate change
- J. Bamber, Nature, February 2012

Another early start with ‘Dynamics of Fjords and High Latitude Estuaries’. A lot of focus is being put on the fjords in Greenland because of the melting ice sheet there. As this ice sheet melts it adds about 0.09 mm each year into the oceans contributing to rising sea levels. The majority of fresh water released from a glacier is due to calving icebergs and melting from beneath the glacier that passes over sea water, only a small portion if due to run off. Increased fresh water can change the dynamics of fjords making an interesting basis for a scientific study.

As a tangent - I wish I brought my camera so I could include some pictures!

Wednesday, February 22, 2012

my brain is full!

I’m at the Ocean Science Meeting in Salt Lake City Utah. After the end of day two, I can officially say my brain is full.

Monday, 20 February 2012 - Day 1

I got up early to attend one of the first sessions of talks titled ‘Integrating Oceanography and Animal Tracking - the Ocean Tracking Network’ as my work is part of this project. An interesting point was raised: “results will not reflect the properties of fish ‘untouched’ by the hand of man.” Putting a tag inside the fish will alter its behavior, at worst the surgery could kill it at best it might swim away after a really bad day.

Tagging fish can answer questions like: how long a fish remains in an area, if they make daily migrations or movement related to tides, or how many of a population stays put compared to numbers that go wandering.Tracking projects were discussed from South Africa to Australia to Canada.

The migrations of the American eel made an interesting tracking example. These eels spend most their lives in fresh water ranging from Greenland to the north coast of South America. At the end of their lives, all of these eels migrate to the Sargasso Sea to spawn. We know close to nothing about this migration, but we do know their population dropped dramatically in the last 30 years.

To learn more and potentially take preservation measures, eels were tagged in the St Lawrence River. 145 eels were tagged in 2010 and 2011. From the acoustic signals recorded we learned that they don’t migrate as a group, and they take advantage of tides and darkness to move. Temperature data showed that unlucky eels were eaten by Tuna and shark as their stomachs are warmer than the surrounding waters.

A twist on finding tagged animals is in testing off the coast of Nova Scotia. Receivers are put on a big enough animal. Since, grey seals range over large areas, they are ideal predators to lead us to feeding hotspots while recording signals of other tagged fish.

Other talks I went to delved into how energy is dissipated from surface waves, decay rates of white cap foam and temperature fronts in the ocean. I found the images of currents that form jets in the southern oceans fascinating as I had no idea it was so complex - the pictures looked like a chaotic mass of snakes.

Tuesday, 21 February 2012 - Day 2

I started with attending Arctic talks in a session titled ‘The Arctic and subpolar North Atlantic as the pacemakers for climate change.’ I’m aware that there is a sea surface height difference between the Pacific, which is higher, and the Atlantic, this results in flow across the Arctic to the Atlantic. What I didn’t know is that fresh water is accumulating in the Arctic, specifically in the Beaufort Sea as a gyre. This gyre as increased in fresh water content significantly since 2003 by 5400 square kilometers. What happens when this fresh water is released? This and other fresh water anomalies could potentially impact our climate if they stop or slow down the Meridional Overturning Circulation - this is a basin wide process in the Atlantic that includes the warm water from the Gulf Stream the keep Europe warm.

I also found it interesting that Arctic observations peaked in the 1980s - cold war related?

My afternoon was filled with talks on flow/topography interactions, an area I looked at in detail for my masters work. The room was packed, meaning this area is very much the focus of active research.

Wednesday, February 15, 2012

How deep is it?

Once a lead line was the only way to figure out how much water was beneath your ship. Now, there are all sorts of options for determining ocean depths from echosounders to satellite images. I suppose one could even venture out with reel of line and a weight, but not me as spooling in kilometres of line is quite tiring.

I wrote about how our technology evolved for determining ocean depths here.

Wednesday, February 1, 2012

Plastic in the ocean – a depressing thought

A myctophids (photo by G. Hanke RBCM)
“No scientist would ever use the state of Texas as a unit of measurement” 
       - Captain Charles Moore

My husband and I went to a talk by Captain Charles Moore recently. He wrote 'Plastic Ocean', a book I'll read and write a review of (we have been planning to get the book for some time). He brought up some interesting and depressing points about how much plastic is in our oceans and what it's doing to the life there.

Only about 10% of the garbage that gets into the oceans washes ashore; the rest is concentrated into the mid-ocean gyres. An unfortunate side effect of our convenience-based consumer lifestyle is that much of the garbage produced is plastics, which float and don't breakdown. It takes approximately 6 years for the garbage to travel around a gyre and the average life of the garbage in a gyre is 10 revolutions – that is 60 years.

At first the plastics resemble what they started as – a milk crate, a laundry basket, etc. Since plastic presents a hard substrate, algae eating fishes claim larger chunks as shelter and keep the surface fairly algae free. This clean plastic eventually gets colonized by barnacles and corals creating a new multi-level trashy ecosystem - with algae as the base, then on to herbivores, planktivores, secondary invertebrate consumers, and so on ending at the top predators (large fishes, birds, dolphins and relatives).

As hard-shelled invertebrates grow, their mass overcomes the buoyancy of the plastic. The reef sinks, and over time, the attached organisms decay or dissolve in the cold ocean depths. Buoyant once again, the plastic floats to the surface and the cycle of colonization can begin anew.

In the long run, this plastic garbage will rub up against other debris or be broken by wave action. The plastic pieces get smaller and smaller. A ruby-red bottle cap might be scooped up by an albatross to be fed to its chick or the plastic rings holding a six-pack together might end up around a sea turtle, restricting normal shell growth. Captain Moore mentioned myctophids, an abundant group of lantern fishes which are a vital part of the open ocean food web. Dissections of their stomachs show some of these fish are eating as much plastic as food. Even the tiniest pieces can be ingested by filter feeders.

Plastics are known to absorb pollutants. Species low on the food web eat plastic scraps, creating another way for pollutants to end up in our food. I wonder, what that tuna I ate for lunch ate for its lunch?

So what can we do? I try to use as little as plastic as possible. I have my own metal water bottle and ceramic coffee cup. I keep food in glass containers, and use re-fillable bottles for shampoo and cleaning products. Any other ideas?

as a tangent: thanks to my husband for helping me with this one.