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Title: In situ observations of benthic and pelagic bioluminescence in the deep Atlantic Ocean and Mediterranean Sea
Author: Heger, Amandine
ISNI:       0000 0001 3552 1859
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2007
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In the studies presented in this thesis, bioluminescence was characterised using a low-light video camera in three deep-water ecosystems and related to bio-physical factors. In the first set of experiments, baited lander deployments were conducted at about 1000 m depth in the NE Atlantic to examine the occurrence of spontaneous bioluminescence on the seafloor. Luminescent activity was higher in an area of soft sediments with 133 events h-1, compared to seven events h-1 in a cold-water coral habitat. The ostracod Vargula norvegica was found to be the major source of these events. In situ and shipboard laboratory experiments revealed what appeared to be a luminescent defensive reaction to the presence and activity of the arrowtooth eel Synaphobranchus kaupii, which were observed preying on the ostracods. In a second study, the construction of a neutrino telescope in the NW Mediterranean provided an impetus to measure the abundance of stimulated bioluminescence at the depth of operation (1950-2300 m). Temporal changes in luminescent activity and display types were observed and it was estimated that the telescope could suffer 25,920 bioluminescent impacts h-1, leading to a detectable light production of 2.6 x 1014 photons h-1. In a third study, profiles of stimulated bioluminescence (to 3000 m) above the Mid-Atlantic Ridge revealed enhanced concentrations of luminescence at a station south of the study area compared to the north, and above the summit of the Faraday Seamount. Image analysis of the seamount profile enabled fine-scale characterisation of luminescent event, such as a layer of trapped luminous sources (possibly euphausiids) and large events (possibly gelata) close to the seamount summit. Measurements carried out within an anticyclonic mesoscale eddy also showed increased luminescent activity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available