RV
Urania
The
RV Urania is a 61.3 m multi-purpose research vessel operated by CNR (Italy).
Multibeam echosounder
Bathymetry
data constitute the main source of information on the morphology of the
seafloor. Bathymetric maps are typically compiled using a multibeam echosounder
mounted beneath a research vessel. Seafloor depth is estimated by measuring the
time it takes for a beam of sound to travel from a sounder to the seafloor and
be reflected back to the sounder. The echosounder features tens of narrow
adjacent beams arranged in a fan-like swath 90° - 180° across. The beams update
many times a second, allowing a wide coverage of the seafloor and generating
bathymetric maps and digital elevation models, as well as maps of the intensity
of the acoustic response (known as backscatter), which provide information on
seafloor composition.
Seismic reflection surveying
Seismic
reflection is a technique that provides information about the subsurface
structure of the seafloor. The general principle involves sending artificially
generated acoustic waves down the water column and into the seafloor, where the
different structures and objects reflect this energy back according to their
acoustic impedance. These reflected energy waves are recorded by hydrophones,
and the data are processed to produce a visual representation of the seabed
subsurface. We will use 2D seismic
reflection methods to produce individual vertical cross-sections of the
seafloor.
Remotely Operated Vehicle (ROV)
An
ROV is an unoccupied, highly maneuverable underwater robot that is operated by
a person aboard the ship. The robot is linked to the ship by cables that allow
electrical signals to be transmitted between the pilot’s control and the
vehicle. We will use the ROV to obtain video and still imagery of the seafloor
morphology and habitats.
Gravity coring
Gravity coring is a simple but effective method to
obtain sediment from the seafloor. A gravity corer consists of a weight
connected with a 6 m long steel tube. The end of the gravity corer is fitted
with a cutter section and a catcher to retain the sampled material. The corer
is lowered to the seafloor using a long wire and is stopped at a set distance
above it. The corer is then lowered at a set speed into the sediment, after
which it is raised to the surface and the sediment is recovered.
CTD
A
CTD is an instrument that measures the conductivity and temperature of ocean
water at different depths. This information is crucial to calibrate the
multibeam bathymetric data. The CTD is mounted on a carousel of vertically
mounted water sampling bottles, known as a rosette.
