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The RVs Ernest I (top) and II (middle) in the field during
nearshore surveys. Ernest II and Roald at anchor at Cape Shirreff
(bottom). Photos by Dave (top), Martin (middle) and Steve
(bottom).
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RVs
Ernest and Roald
The
key component to the LINKES project is the small boat survey operations
that occur in the waters near Livingston Island. These waters are not
well charted and have highly varying bathymetry so the larger vessel
can not survey these areas. We know these regions are highly productive
from small boat operations conducted in 2000,
2002 (
small boat and
buoys ), and 2004;
as well
as from foraging tracks from the sea birds and marine mammals that the
group at the Cape Shirreff field camp has studied. By instrumenting
small (19') inflatable vessels, we can survey areas that no other
Antarctic vessels can. Of course, this survey work also requires the
ability to endure cold temperatures and wet conditions, although
nothing like the original Antarctic explorers had to endure (e.g.
Ernest Shackleton and Roald Amundsen, the namesakes for our nearshore
survey
vessels).
The Ernest I contains an aluminum insert built by Leif
Knutsen and featured a single-frequency, split-beam EY500 echosounder,
a WeatherPak 2000 meteorological station, motorized down-rigger for
deploying a SBE 19 SeaCat CTD and digital underwater video camera,
redundant GPS systems, redundant VHF radios, Raytheon 24 n.mi. radar,
several laptop computers for recording data and a battery bank to power
the system. The Ernest II replaced the aluminum insert with a
metal-framed dodger which offers more protection from the elements and
includes many of the same features of the Ernest I with several changes
including: the echosounder is a dual-frequency ES60 system and surface
temperature and salinities are recorded by a SBE MicroCAT.
The Roald has a similar dodger to the Ernest II, however its
instrumentation is a multibeam acoustic system (SIMRAD SM 2000,
supplied by Jeff Candiotty of Simrad, USA) and associated geographical
positioning sensors. A specialized deployment arm system (designed by
Derek Needham and David Demer) allows two people to deploy and recover
the multibeam system from the small boat. The RV Roald was jointly
funded by: The UK Royal Society / NERC (Natural Environment Research Council);
Simrad, USA; the U.S. AMLR Rrogram; and SWFSC's Advanced Survey
Technologies Program.
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RV Ernest
- Meteorological Observations
On the roof of the RV Ernest (both I
and II) is a
WeatherPak
2000 meteorological station (identical to the ones mounted on the RV
Yuzhmo with the exception of the PAR sensor). The weather station data
is recorded by the laptop inside the weathertight case and displays
meteorological information such as wind direction and speed, air
temperature, and (most importantly) atmospheric pressure. We use the
meteorological information to make decisions about which survey
tracklines to run and when to head back to our mooring at Cape Shirreff
when the weather may turn for the worse. |
The RV Ernest at work. The meteorological station is mounted on the
roof of the boat. Photo by Martin.
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RV
Ernest - Video and Net Sampling
The RV Ernest uses a
digital videocamera in a waterproof housing to
collect video data about the scattering layers observed in the ocean
and can deploy a
small
ring net to catch specimens in the upper most portion of the water
column.
The camera is connected by a cable to the ship where a small hand-held
monitor is
used to determine when the video system is in the middle of a krill
patch. The data from the camera allow us to sea-truth the acoustic
data, as well as provide information regarding the krill's behavior and
orientation in the water column. |
RV Ernest
- Surface Temperature and Salinity
The SeaBird MicroCAT is attached to
the
echosounder mounting arm and collects temperature and salinity values
at
approximately 1 m depth every 15 sec during the survey. Given the
turbulent nature of the upper water column in the nearshore area, where
seas are typically between 1 - 4 m, the waters sampled by the MicroCAT
are well-mixed and often reflect changes in atmospheric temperature.
However, the salinity records do indicate changes in surface salinity
throughout the survey area. This data is complementary to the
hydrographic information collected aboard the RV Yuzhmo. |
Martin and Adam aboard the RV Roald. Photo by Steve.
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RV
Roald - Multibeam Acoustics
A second instrumented small boat participated in the nearshore survey this year. Andrew Brierley and Martin Cox (Univ. of St. Andrews)
are collecting multibeam acoustic data using a SIMRAD SM 2000 system,
supplied by Jeff Candiotty of SIMRAD, which is being used to
conduct a detailed bathymetric survey of the canyon to the east of Cape
Shirreff as well as water column backscatter data. Martin was on the
boat running the system
which collects data that can also be used (if the animals are not
feeling too shy) to observe predator and prey interactions in situ.
Additionally, the multibeam data can be compared (although not
directly) to the echosounder data collected by the RVs Ernest and
Yuzhmo. The multibeam acoustic survey was jointly funded by: The UK
Royal Society / NERC (Natural Environment Research Council); Simrad,
USA; the U.S. AMLR Rrogram; and SWFSC's Advanced Survey Technologies
Program. |
Bird
and
Mammal Observations
For the 2006 field season, personnel onboard
the
RV
Ernest (Steve Sessions, Joe Warren) and Roald (Adam Jenkins, Martin
Cox) worked with Jarrod Santora on identifying and recording
information about the bird and mammal predators seen in the nearshore
area. Anecdotal observations during previous field seasons
have
indicated that if penguins are observed then the echogram will show
large krill patches in the water column, as well as the fact that
baleen whales are regularly observed feeding in the nearshore area
during the survey. However, this year we are attempting to collect
quantitative data regarding these predators which can be integrated
with the observations made from the RV Yuzhmo.
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Two chinstrap penguins porpoise through the water.
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