Sunday, June 6, 2010

Experiments, a labyrinth, and dunes

By Laurel
This week in the lab, I conducted the first run of an experiment for my project. I learned many things along the course of the week. To describe it without photos....

My experiments contain an adsorption step and a desorption step. The heavy metal I am working with is Zinc. I first made a Hoagland solution, which is a solution for growing aqueous plants, containing nutrients and trace elements. Using a scheme of controls, I added Zinc to some of the samples and incubated all of the samples in small plastic trays overnight. During this step, in the samples containing Zinc, the some of the Zinc will adsorb to the surface area of the duckweed plants. Also during this step, some of the adsorbed Zinc will be uptaken into the plant cells. The goal of my experiments is to find out how much Zinc is uptaken and how much is just adsorbed to the plant, and show this using a mass balance on Zinc.

The second step in my experiments is the desorption step. For this step, I added EDTA diNa to some of the samples, which is a metal chelator, meaning it binds to metals. Adding EDTA will desorb the metals that have been adsorbed to the surface of the plants, but will not change the fate of the metals that have already been uptaken into the plant cells. In this way, we hope to be able to distinguish how much of the metal is adsorbed the the plants, but not uptaken.

Following the adsorption and desorption of the Zinc, I collected and acidified water samples from all of the respective samples in the experimental scheme. What is left to do is analysis. I will digest the plant samples from this experiment with nitric acid and the digested plant samples and water samples will be analyzed on the Atomic Adsorption Spectrometer.

I am enjoying my time thus far working with plants. You have to get them to grow for you in the lab so that you can do experiments without collecting plants from the wild again. Part of my lab time always includes checking in on the plants, feeding them primary effluent, harvesting them so they don't get overcrowded, making sure the light intensity is right for them....

My story this week is about a 30 mile bike ride I went on (by the map, not including me getting somewhat off the paths and also riding around exploring) yesterday. Due to an excellent bike and much stretching, I am happy to say my knee felt perfectly fine at the end of the ride!

Luckily for me, I picked up a good bike map which includes Den Haag and the Dunes on the coast from the Den Haag tourist office before leaving on my bike ride.... It was another gorgeous sunny day in the province of South Holland, and I decided that I would ride to the coast near Den Haag and then bike along the dunes north for a while and then turn around and bike back.

I took a more scenic route north (not the one that runs straight to Den Haag), but one that ends up on the coast further south of Den Haag. On the way to the coast, I was biking down a forested trail when all of a sudden, I came upon a hedge on the side of the path. The hedge was surrounded by farm fields- maybe hay. I turned my head and did a double take because it was no ordinary hedge. I had just stumbled upon a labyrinth! The labyrinth is an ancient meditation and spiritual tool- not a maze, but a path winding inward to a central circle. You may think of the greek myth of the Minotaur in the labyrinth. Anyway, this labyrinth did have dead ends, so it was not the traditional labyrinth in the sense of having only one path to the center. I walked through it, reaching the center which was a spiraled raised circular platform of stone. The labyrinth is obviously maintained, but I wonder how old it is. It could be very old indeed.

After the labyrinth, I continued on to the coast. I learned over time how to properly read the bike junctions on the map and how to look for the bike signposts that cover this country, but tend to disappear in a city or metropolitan area. I ate lunch by the North Sea. I had reached the dunes, or duins in Dutch.

The dunes were very pretty. I wished I had brought a bike lock to lock the bike and be able to walk on some walking paths through the dunes. Anyway, I carried my bike up to a lookout over the dunes and listened to whoever was opening for the outdoor Bon Jovi concert yesterday that was outdoors and thus amplified so I could hear it in the nearby dunes.

Up the coast, and the dunes were beautiful, but tiring because they were actually hills for a change from the flat landscape. Very suddenly, though, the dunes disappeared behind me and everything was flat again. By that time, I was tired, and instead of turning around as I would have had to do in most places, I decided to take a train home. You have to love the Netherlands for that combination: great bike trails and great public transit.

Inland to Leiden. When I reached Leiden, it was 4 p.m., and a little early to be going home. Instead I biked around looking for a castle marked on my map. I never found the castle, but I got to see a bit of the city of Leiden, which is located on the River Rhine, and has many nice places to eat or sit next to the river. It was a very pretty area, and I want to go back there some evening by train to explore it and hopefully find the castle, which is open to the public.

Back in Delft, the Mooi Weer Spelen festival was taking place. People were crowded into the central square for performances. The highlight was a night performance which included 8 dancers, a singer and a band, a crane, and a large steel ball. I will leave that to someone else to describe.

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