Sediment traps Options

[Robert_Oddo]

Monday August 8th

Today we pulled a number of sediment traps that were deployed at different times in the past year. A sediment trap is just a funnel with a plastic lattice over the top. You attach these funnels to a rope at various depths and then attach a rock to the bottom of the rope and a buoy at the top. These were placed at various places in the lake. It is important to mark the position of these traps with a GPS unit because it is hard to find them a year later. Sediment is not deposited in the lake uniformly and the people that I am working with are trying to understand how and when the sediment is deposited. Some of the traps we pulled were put in the lake in August last year and some were put in April this year. We are interested in finding out when the majority of the sediment was deposited, in the late spring when the ice melts or in the fall.

We also worked today measuring the gradient of the land from the lake to the moraine at the base of the glacier. It is about 6 km distance. What we did was measure out 50 meters with a tape measure. At one end of the tape have a Jacobs staff (a pole with a device that can measure incline of the slope) and at the other end a 4 meter pole that was marked in .25 meter intervals. So far we have measured the incline for about 50 50 meter intervals.


So far, I have talked a lot about collecting data. What about analysis? The field season is short up here and our work is really focused on collecting the data. We are up and getting ready to go out in the field between 7:00 am and 8:00 am every morning and get back between 6:00 pm and 7:00 pm. We do some crude analysis back at the field station but most of the analysis will be done in the fall and winter. A lot of the work when we get back to the field station is preparing the samples we have collected for transport back to the States. We have filtering setups in some rooms and a garage where we were store a lot of the other materials. Additionally, we spend a lot of time back at the field station downloading data off of devices like data loggers, sea cats and field laptops.

In the last week the weather has started to change. It has gotten a bit colder and we have a lot more fog. The sun is also a lot lower in the sky and the shadows get long at night. But the sun has not set. Even though it doesn't get dark you can tell how night from day by the length of the shadows and how bright it is outside.


This is what a sediment trap looks like.

Nora with the Jacobs staff and Fran with the GPS measuring incline. It was cold!!!

One of our lab areas where samples are filtered and prepared

data loggers waiting to be downloaded