Rob Jacobsen

Field observations and sample collection at Laguna Negra offers lots of useful scientific data for the PLL team. However, some places around Laguna Negra are inaccessible because of steep terrain and distance from base camp. PLL remote sensing uses cameras on the ground and in space to fill gaps and better complete the information about the Laguna Negra system.

One area of particular interest for the PLL remote sensing team is the influence of geology around Laguna Negra. Laguna Negra is surrounded by many volcanic and plutonic igneous rocks, such as basalt and granite. These rocks weather and erode to form smaller pieces and new compositions. Some compositions are useful nutrients for lake organisms. PLL remote sensing uses a technique called reflectance spectroscopy, which measures the unique radiation signatures of different rock compositions. At Laguna Negra, a reflectance spectrometer measures rock compositions near base camp. These measurements are then compared with satellite spectroscopy data to understand geologic compositions around the lake.

Although reflectance spectroscopy indicates which rock compositions surround Laguna Negra, it does not explain how such material enters the lake. PLL remote sensing uses thermal imaging to study the transportation of rocks and minerals into Laguna Negra. From base camp, a thermal camera measures hillside temperature changes over a 24-hour period. Surfaces with different rock grain sizes and vegetation will have different temperatures throughout the day – sands heat up early in the morning, while boulders stay cold until the afternoon. This property is called thermal inertia. Measurements of relative thermal inertia, along with surface slope angles, indicate which fine grain material is most likely to enter Laguna Negra. Combining this information with composition data from reflectance spectroscopy helps the PLL remote sensing team model the input of geologic material around Laguna Negra. Such information helps other team members understand the interactions between lake biology and lake geology.

Team: Jeff Moersch (Co-I), Robert Jacobsen (Graduate Student Team Member), Matt Smith (Graduate Student Field Assistant) University of Tennessee

Q. Can you share some of the details on the design of the robot(s)?
How big are the robots being designed to explore Titan? How many
robots will explore? What do the robots actually do?
A. Several different ideas have been proposed to explore Titan, from
lake landers to airplanes to balloons.  The lake lander is the most
exciting, as it would be able to float across the surface of a large
Titan lake, measuring what they are made of, and measuring the winds,
waves and changing weather. Titan is the only place where we could
actually use the same tools we use to explore lakes and oceans on
Earth on another planet!

Q. What about this project has surprised you?
A.  We have been surprised by how fast the glacial landscape is
changing in the Andes. We are able to quantify how climate change is
causing a rapid loss of ice in Andean glaciers, which are the main
water source for the people of the region.
We are also pleasantly surprised by how projects evolve and improve
from our original concept to an actual lake lander, gathering new data
and improving our understanding of the lake and its environment. Often
the path to the end product is not what you expected when you thought
up the original concept, but it is always better, and is the product
of many talented people from different disciplines (engineering,
geology, biology, chemistry) working together as a team.

Q. Is the research dangerous to you? How much of a problem is
radiation to you? How about the high altitude and low pressure? What
precautions do you need to take to live in such high altitude in the
Andes? If there are extreme weather conditions do you still proceed?
A. The UV index, a measurement of the strength of ultraviolet
radiation coming from the sun is normally considered extreme at 11:
here at the site in the Andes it is between 15 and 17. So we put on a
lot of sunscreen and try to keep as covered up as possible. Hats are
always on! The altitude is only about 2700 m, so not too high. We have
lots of changes in the weather, from beautiful warm sunshine to high
winds, snow and hail! We make judgment calls on what work to do, being
very careful to understand that weather can change rapidly in the
Andes. There is always lots of work to be done both on the lake and
back at camp, so we keep busy no matter what the weather!

Q. How does the topography of Earth compare to that of Mars and Titan?
Does the topography present different problems/challenges?
A. The Earth’s surface is shaped by plate tectonics, so we have
distinctive low ocean basins and higher terrain on the continents.
Mars and Titan are single plate planets, and so have a more uniform
distribution of topography. However, Mars, more like Earth, has had a
lot of volcanic and tectonic activity, that has formed the tallest
volcano in the solar system (Olympus Mons) as well as very deep and
large canyons (Valles Marineris). Titan has a lot of erosion from its
methane rainfall and little tectonic and volcanic activity, and so has
very low topography. Topography is challenge of you are trying to land
a rover, so the Curiosity rover had a radar to make sure the landing
site was safe. That is certainly an advantage of landing on a lake on
Titan- a very flat and safe surface!

Q. What do you do with results when you think you have something
relevant or correct but you’re not sure (in this particular project)?
A.  The scientific process always consists of forming a hypothesis and
then testing it by collecting data. Your data will tell you if you are
on the right track, or wrong, or somewhere in between. With more
information, your hypothesis changes, allowing you to ask better, more
specific questions. You learn as you go along, discussing your results
with colleagues and writing up your findings in scientific journals so
that the scientific community at large can further test your ideas.
You are always learning, always adapting to new data and new ideas.
For example, we saw that the average temperature was not changing
much, but by digging into the data, we learned that there was a great
deal of temperature changes in certain seasons, that is the cause of
the increased glacial melt. We also found fishes very deep in the lake
- 200 m- which tells us there are nutrients deep in the lake. We do
not know where they are coming from, so we are developing new
hypotheses to test.