Getting
Wireless Video to the Shrimp
Dr.
Todd Crowl, Utah State University has been studying the fresh water
shrimp of Puerto Rico for 8 years now. The location for the study
is a secluded pool at the base of a small waterfall on the Rio Espiritu
Santos just outside the boundary of the Caribbean National Forest.
It is close to the road that leads to El Verde research station.
In fact it is at the bottom of a steep hill behind what is called
the Stream House which is part of the El Verde Station complex in
the El Yunque rain forest.
While Todd travels to Puerto Rico periodically for his studies,
and uses graduate students to observe the shrimp, video taping them
at night under red lights during their migration, the observations
must be, of necessity, sporadic.
What
Todd would like my NSF Project to do is see if we can install a
web-server wirelessly connected video camera that can continuously
produce video images of the shrimp in their natural environment
in the pool, and stream back the images wirelessly and via the Internet
to his Utah offices, where they can be observed both real-time,
and taped as desired.
This
is a challenge for several reasons. First of all there is not yet
an Internet POP closer than 30 miles away in San Juan at the University
of Puerto Rico as of October, 2000. However the bids have been solicited
by the Luquillo LTER to extend the Internet wirelessly to the El
Verde Station, including an extension to the Stream House, about
200 meters from the river and pool. So an Internet connection may
come close to the river in the near future.
The
Stream House at the top of hill above Rio Espiritu Santos .
Secondly
the delightful shallow little stream, just a few inches deep as
it passes this point well up toward its headwaters in the rain forest,
turns into a raging torrent, up to 20 feet deep when one of the
periodic storms passes over. El Yunque rain forest gets 100 Billion
gallons of water falling on it annually and the tributaries of the
various rivers which have their headwaters in the forest can create
flash floods.
So
how to protect the camera when these largely unpredictable events
occur?
At
my last visit to the island during which the final installation
of the 6 radios on the weather stations was completed, I visited
the shrimp pool site near the Stream House to determine the questions
which needed technical answers.
Clambering
down the slope was interesting. No simple path exists. The jungle
vegetation covers the steep muddy slope. Halfway down is a shelf
with large white plastic weirs that have been installed to hold
fresh running water from the stream and held in four large tanks
at one end. This work-in-progress is in support of later controlled
studies.
Having
made a mistake in my choice of route down the first time, I waded
through thick, large frond plants, some of which were covered by
sharp needles to deter animals from eating them. They contained
a little stinging poison that covered my hands and hurt for a good
half hour. But some of the flowering plants were lovely.
The
stretch of river where the pool stands on a flat portion of the
riverbed is about 30 meters long. At one end is the rock outcropping
down which the stream flows, forming a cascade.
The
drop is about 5 meters, At the other end, downstream, is a stretch
of quite large boulders - one meter or larger stones that have bounced
down the river during one of those gulley-washers and were pushed
by the force of the water across the pool flats area to come to
rest further away.
The
pool itself is about 7-10 meters across. Closest to the last waterfall
- or more accurately a 'cascade' down the rocks, there is a shallow
sandy bottom. 10 meters further it reaches its deepest, about 1
to 2 meters. The water is quite clear. One can see the bottom rather
well, as shown below.
Not
knowing without talking to Todd Crowl after having seen the layout
of the site, exactly what he wants to observe with a remote camera,
I looked around for shrimp. Not being familiar with what fresh water
shrimp looked like, I peered around until, I spotted, on a gray
rock slab that extended down to the bottom, some curious, wandering
markings. Then I looked closer seeing small - white shells. There
they were, tiny shrimp scouring the deposits on the rock! Leaving
a trail behind.
I
soon counted at least 25 shrimp on that slab within about a 2 meter
radius. This picture is of one rock face in shallow water with the
shrimp - the small white dots - and the scouring trails they leave
behind.
It
would not be that much of a challenge to set up a wirelessly connected
camera at this site. The Stream House is in view, the distance short,
and the vegetation sparse enough between the river bottom and the
top of the Stream House building to let the wireless emissions through.
But how to protect the camera? Or even give it a panoramic capability,
remotely controllable?
Except
for the top of a rock in the middle of the cataracts that looked
at least 8 meters high and above the highest water mark I could
see, and one mature tall tree close to the slab of shrimp that had
not been washed away, there was nothing else to suspend a camera
from.
It
might be possible to suspend the camera, and with some sort of rising-water-upstream
communicating warning sensor, be able to snatch the equipment up
high when the floods come. Or, of course, we could devise a housing
that can take lots of abuse, and stay in the water through the aftermath
of the legendary storms that rage over El Yunque.
But
the final solution will have to await discussions with Dr. Crowl,
to first insure that the installed wireless camera first supports
his science, and then make the safety of the equipment a second
priority. It may be that we look for 'disposable' cameras that can
do the job.
