Greetings dear reader,
I write again from the Samoylov Research station in the Lena River Delta. After the three summer months away from Russia, I am now back to observe the landscape's transformation into autumn and perhaps even the winter.
I am here this time with Alexander Sabrekov, a Ph.D. student from Moscow State University's Faculty of Soil Science. We had an easy arrival to the island, with no significant delays in Moscow, Yakutsk, or Tiksi. Our final journey to the island was by the small Ural boat (Tuesday, 3 September).
In our journey across the delta's channels we were able to wave hello to the boats carrying the scientists of the August expedition back to Tiksi. The island had only a few hours break between the August and the September crews. We regret not having the chance to greet and exchange ideas with the previous group!
Alex and I know each other well: we worked together here last summer making chamber measurements of surface-atmosphere fluxes of methane from different landscape units. What does that mean? Different landscape units have different ecological and physical properties such as: dryer or wetter areas, regions with more or less plants, areas with different clay or organic soil fractions.
These differences create changes in the microbial communities in the soils; these communities then produce greater or lesser quantities of the greenhouse gases methane and carbon dioxide. We measure this production in site using the flux chamber technique. This method essentially involves a scientist placing a closed box (60 cm x 60 cm) over the ground.
The concentrations of the greenhouse gases in this box increase over a given time period (generally, half an hour) as the gases diffuse out of the ground where they are produced by the microbial communities. The chamber air is sampled into syringes to be analyzed back at the station laboratory's gas chromatograph.
These measurements provide a vivid reminder of the different ways a landscape responds to its local setting – rains can trigger pulses of behaviour, waterlogged soils produce more methane than dryer soils, organic matter is correlated to greenhouse gas production. To take advantage of this technique, this fall, Alex and I are conducting these measurements in the half of Samoylov Island that is flooded annually.
This lower part of the island I saw nearly covered by the Lena River during its peak flows in May. The river brings a fresh load of nutrients, sand deposits, and a major annual disturbance. The plants in this part of the island are often higher and denser than in the elevated regions covered by ice wedge polygons. There are even many shrubs in the willow genus, though at less than 1 m in height, they hardly resemble the large weeping willows of European gardens. Up to 20% of the delta is covered in this type of annually-flooded vegetation, so understanding how this floodplain behaves on Samoylov will enhance our abilities to predict how the whole delta functions.
Our other tasks, which I will discuss in more detail in future posts, include observations of the hydrological cycle as the landscape begins to re-freeze in the movement toward winter. We will also work to make sure our measurement systems, installed in warmer periods, are ready to withstand the winter chill (which may reach temperatures as low as -50°C). Technical installations tend to enjoy these temperatures as little as their human operators! For now, we enjoy the bright reds, oranges, yellows, and occasional greens in the autumnal landscape.
Greetings dear reader,
This week on Samoylov has been a good time to reflect on how the station works and operates, and how it can survive the cold winter conditions up ahead. This week we saw the arrival of a fuel vessel delivering 250 tons of diesel oil.
This is a LOT of fuel – enough to drive a midsize car nearly 3 million kilometers! One of the special safety features of the station is that it should always have enough fuel for not only the winter coming, but for the next two winters, in case supply problems inhibit fuel delivery in any one summer. A hose from the ship led into one of the four large diesel containers next to our station and let loose its cargo for several hours to fill it.
Inside the station too, work abounds. One of the most obvious was work on the floor tiles, which have been coming loose inside the station. One of the staff members has labored to re-set the tiles, cementing them into place once more. This process led to a few days of walking between our bedrooms and the rest of the station on planks, as in a very low-wire circus. Similar "floor work" has taken place around the station's grounds, as planks and platforms have been put down that will support vehicles and pedestrians alike during the snowy months just around the corner.
The lone scientists, Alex and I, have also been working – in addition to the chamber measurements described last week, we have also been collecting and analyzing samples of water from different portions of the island.
We are interested in studying connections between the amount of carbon and other nutrients in the soil's water and the greenhouse gases leaving the soil.
The hypothesis is that a richer nutrient base will improve bacterial activity, and this greater bacteria mass will generate higher amounts of methane and CO2.
So far we have seen some regions, particularly in the floodplain, where the water quality does not change as much as the gaseous emissions do. In other regions, such as the polygons, the water quality changes quite substantially as you move through the soil's layers.
In the coming days we hope to have enough data to test and analyze this hypothesis.
In the meantime, there is an island of tundra to explore, a station being continuously maintained, and yet more samples to gather.