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Heinrich Events (HEs) define intervals of major ice rafting from the Laurentide Ice Sheet (LIS) into the North Atlantic during that last glacial period. The discovery of potential European-sourced precursors to HEs suggest that the smaller, but climactically sensitive, European ice sheets (EIS) may have played a role in the triggering of HEs and their impact on global climates. Environmental magnetism has proved itself to be a useful, rapid and non-destructive tool in the identification and quantification of provenance in sediments from various depositional environments. In this work, environmental magnetic analyses are applied to marine sediment records from the European margin of the NE Atlantic and known to contain ice-rafted debris (IRD) from both LIS and EIS sources. The primary aim in the work of this thesis is to evaluate the methodology as a means of distinguishing IRD provenance. From the data obtained here it is possible to identify several magnetic events that correspond to the HEs and other layers of detrital material and which correlate well to previous standard petrological analyses performed on the same core materials. Magnetic signatures differ within the HEs, suggesting a changing balance of input from multiple sources as opposed to a single LIS source. The data suggest a phasing of these compositional differences through individual HEs. The potential of using environmental magnetic techniques in the identification of IRD provenance within marine sediments is discussed, as is the significance of the observed provenance variations within the cores studied.

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The western North Atlantic population of the northern right whale (Eubalaena glacialis) was severely depleted by whaling over the last century. Despite over fifty years of protection, fewer than four hundred individuals are believed to exist in the North Atlantic. Relatively little is known about the diving behavior, respiratory physiology, or diel activity of these whales, although such information could be useful in predicting population abundance and distribution in relation to food or environmental variables. Dive behavior data can be collected visually, but collection is limited to daylight hours, calm weather, and fortuitous encounters with study animals. Satellite-monitored radio tags offer the opportunity to collect data on individual whales' diving behavior continuously, over long distances and periods of time, and at relatively low cost. Thirteen North Atlantic right whales were tagged and monitored in the Gulf of Maine between 1989 and 1991. One male was tagged in 1989; two adult males, six adult females (two with calves) and one juvenile were tagged in 1990; one adult female (with a calf) and two juveniles were tagged in 1991. The duration of monitoring for the whales varied from <1 day to 43 days. Characteristics of the radio tags were different over each year in order to evaluate different attachment mechanisms and methods of collecting and summarizing data for dive duration, dive frequency, and time submerged. These data were then used to describe the dive behavior and to predict aspects of the respiratory physiology for these whales. The number of dives, their duration, and the time submerged varied considerably among individual whales and between years. Over all, the whales spent 79% of their time underwater. However, most dives were short (i.e., 95% were <14 min; the mean dive duration was 92.3 sec), although dives of 30-40 min duration were observed for several individuals. In general, the number of dives a right whale made was inversely related to the average duration of its dives within a time interval. Furthermore, over a given time interval, the number of times a whale dove was a better predictor of the percent time it was submerged than was the average duration of its dives. There was no evidence of diel variation in dive behavior (i.e., number of dives, average dive duration, or percent time submerged) among these whales. Age, sex, and reproductive status may have affected dive behavior, although these trends were not statistically significant due to the small number of study animals and individual behavioral variability. Males tended to dive more often and averaged shorter dives than females. Females with calves dove more often and averaged shorter dives than females without calves. Juvenile females dove less often but averaged longer dives than adult males or females with calves. It was predicted that the aerobic dive limit of an "average" right whale was approximately 14 min. Ninety-five percent of the dives recorded for the 11 monitored right whales were < 14 min. Furthermore, there was no evidence of recuperative periods (i.e., prolonged periods at the surface) after long dives. These observations were consistent with the idea that the North Atlantic right whales dove within their aerobic scope. They further suggest that physiological parameters alone probably have little influence on dive characteristics, except to set an upper limit on the duration of a dive. Satellite telemetry provides an opportunity to monitor the movements and behavior of free-ranging animals, and overcome many of the short-comings associated with traditional, human-based visual techniques for tracking and studying such animals. Although the tags used in this study were prototypes and varied in their design from year to year, several right whales were monitored simultaneously and were tracked over thousands of kilometers. Advances in tag miniaturization, attachment, and software will likely extend the time tags stay attached and the detail of the behavioral and environmental variables that can be monitored. As testimony to the power of this technology, this application of satellite telemetry to monitor great whales yielded one of the most extensive, long-term, continuously-monitored data sets yet recorded on the diving behavior of a baleen whale. / Graduation date: 1993

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Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Vita. / Bibliography: leaves 122-129. / by Harry Leonard Bryden, Jr. / Ph.D.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Microfiche copy available in Archives and Science. / Bibliography: p. 239-241. / Ph.D.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Vita. / Bibliography: leaves 170-173. / Ph.D.