Publication Date:
2022-05-25
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2000
Description:
A spectral camera (ALISS - Ambient Light Imaging and Spectral System) was used to
image ambient light from high-temperature vents at 9°N East Pacific Rise and the Juan de
Fuca Ridge during 1997 and 1998 Alvin dive cruises. ALISS is a low-light digital camera
with custom-designed optics. A set of nine lenses, each covered by an individual bandpass
filter (50 and 100 nm nominal bandwidths), allows vents to be imaged in nine wavelength
bands simultaneously spanning the range of 400-1 000 nm. Thus, both spatial and spectral
information are obtained.
ALISS was used to image three types of vents: black smokers, flange pools, and beehives.
The primary source of light is thermal radiation due to the high temperature of the
hydrothermal fluid (-350°C). This light is dominant at wavelengths greater than 700 nm.
At flange pools, where the fluid is relatively stable, only thermal radiation is present. Black
smokers and beehives, however, are subject to mixing with ambient seawater (2°C) leading
to mineral precipitation. Data from these types of vents show the existence of non-thermal,
temporally varying light in the 400-700 nm region. This light is probably caused by
mechanisms related to mixing and precipitation, such as chemiluminescence,
crystalloluminescence and triboluminescence.
Keywords:
Hydrothermal vents
;
Thermoluminescence
;
Thermoluminescence dosimetry
;
Underwater imaging systems
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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