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Nigel Wattrus Chat Session
Moderator: Hello, and welcome to Bell LIVE!'s host researcher
chat session. Today we are going to talk to Nigel Wattrus of the Large
Lakes Observatory.
Nigel Wattrus: Good morning !
Moderator: Hello! Why don't we start of with you telling us what
you study and what the Large Lakes Observatory is.
Nigel Wattrus: Fine. I'm a geophysicist which means I use physics
to learn about the Earth - in particular whats happening at and below
the lake floor. The instruments that I use for my research use sound waves
to map the lake floor. The Large Lakes Observatory is a research facility
of the University of Minnesota here in Duluth whose mission is to study
the large lakes of the world. We have several faculty her with diverse
backgrounds. We often work together on projects and these take us all
over the world.
Moderator: Jennifer from Iowa wants to know why you like to study
geology and geophysics.
Nigel Wattrus: Hi Jennifer ! I became interested in Geology when
I was high school back in England. We took lots of field trips and I enjoyed
learning about "how the rocks got to look loke they do today". My interest
in Geophysics grew when I was at university in England (doing a Geology
degree) - I learnt about earthquakes and how we could learn things about
the subsurface using them aswell as man-made ones!
Moderator: Matthew from Minnesota was wondering, "How deep is the
deepest spot in Lake Superior?"
Nigel Wattrus: Well its not quite as deep as we once thought! The
deepest spot is in the eastern part of the lake, just north of Munising,
Michigan. We used to think the lake was just over 400 m deep but we (LLO)
did a high resolution bathymetric (depth) survey of that area last year
and we now know that it is actually 389.6 m deep - still 28th deepest
lake in the world!
Moderator: Annie, also from Minnesota wants to know, "How do you
take pictures of the bottom of the lake?"
Nigel Wattrus: Good question ! We can't use photographs because
light doesn't travel very far through the water, so we use sound instead!
Sound will travel great distances in water and we can create with our
instruments "pictures" of the lake floor by measuring how long it takes
for sound waves to bounce of the lake floor and how strong the returning
echo is (the strength of the echo is linked to the composition and shape
of the lake floor).
Moderator: Jane from New York was curious, "What are some other
lakes that you've studied?"
Nigel Wattrus: I've studied lakes in Africa (Lakes Edward and Victoria
in East Africa) and Central America (Lake Nicaragua). Other researchers
here at the LLO have worked on many of the big East African Rift Lakes
aswell as Lakes in the former Soviet Union and China.
Moderator: Dave from Wisconsin wants to know, "What kind of special
computers do you use when you work?"
Nigel Wattrus: As you might expect we use a lot of computers in
our work. We have several PC based systems on our boat the R/V Blue Heron.
In addition many of the specialized instruments I use in work are really
"glorified" computers, dedicated to one specific purpose. Here at the
lab I use PC and Unix workstations to process the data I collect. You
might be intersetd to know we try and use PCs in the field because its
much easier to find a new PC board in Africa than it is one for a specialised
Unix workstation!
Moderator: Matthew is wondering, "What is the deepest lake in the
world?"
Nigel Wattrus: Lake Baikal in Siberia is, its over 1700 m deep
(wow!)
Moderator: Chris from New York wants to know, "What do you do with
the pictures of the bottoms of the lakes?"
Nigel Wattrus: The pictures of the lake floor can tell us lots
of things. For example we learn things about its composition which might
help us to understand the lake's history or what's happening on the lake
floor today - the lake is not static and sediments are moving all the
time in response to bottom currents and storms on the lake. Our pictures
also help other reseachers for example they can help explain why fish
concentrate in particular spots when their spawning.
Moderator: Annie was wondering, "Do you know if there has ever
been an earthquake in Minnesota?"
Nigel Wattrus: Yes Minnesota does have earthquakes - but they're
not very common and they're always very small. One of the most recent
earthquakes in Minnesota occurred near Morris MN in east-central Minnesota
in the early 1980s. That was a pretty big one by Minnesota standards -
but most folks didn't feel it! The reason why we don't have many is because
the state sits on some very old and very stable rock far from any active
faults!
Moderator: Jennifer wants to know, "Do any animals live down in
the deepest part of lakes?"
Nigel Wattrus: Yes they do - actually quite lot, many of them have
special adaptions that allow them to live there year round.
Moderator: Okay, last question. Matthew was wondering, "Have you
ever gone swimming or scuba diving in Lake Superior?"
Nigel Wattrus: I do swim in the lake - but only on really hot days
- its very chilly - brrr! I don't scuba dive myself, but we do have a
diver on our boat who has dived in Superior for me (to install and check
my instruments that hang off the bottom of the boat).
Moderator: Great questions everyone, but I am afraid we have run
out of time. I would like to thank Nigel Wattrus for taking the time out
to answer our questions. Make sure you look for him in the up-coming broadcast
on October 12th! Our next chat session will take place with Limnologist,
Robert Sterner at 1:00 PM today. See you then!
Nigel Wattrus: That was fun - see you next week !
Nigel Wattrus: logs off
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