Scientist report - Biochemistry


LAB

Today we determined the relative salinity and humidity of the five soil
samples from yesterday using the following protocol:

- Salinity: 1 g of each soil sample was suspended in 25 ml of distilled
water. The suspension was then mixed and allowed to stand for 2h in
order to give the salt time to dissolve. We then used the millimeter to
measure the resistance of the mix which can be compared to a standard
curve of pure NaCl to roughly estimate relative salinity. To make sure
that this was done with a constant distance between electrodes, we
build a simple testrig consisting of a falcon tube with electrodes
attached to its cap.

- Humidity : approximately 5 g of each soil sample soil was placed on
pieces of aluminum foil and the weight of both the foil and the soil
samples was noted down accurately. Soil samples where then placed in a
drying oven (set to 50 degree C), and allowed to dry until all the
water had evaporated (for 24 hours to be sure). The loss in weigh for
each sample was then determined by and expressed as % humidity before
drying.

Using these protocols, we will determine relative salinity and humidity
for each soil sample collected for the RSL project. This data will
complement GPS coordinates, photos of the collection site and soil
temperature already routinely collected.


EVA

We went to the two more promising sites to collect more samples. The
sampling procedure that we previously set up was followed. We filmed
everything, in order to complete the "Sampling procedure" movie.