Synoptic Variability of Flows Among the Factors in Reference to Conditions for Beluga Whale (Delphinapterus leucas) Occurrence and Distribution in the Laptev Sea.

Alexandrova, Alina (2011) Synoptic Variability of Flows Among the Factors in Reference to Conditions for Beluga Whale (Delphinapterus leucas) Occurrence and Distribution in the Laptev Sea. (Master thesis), Saint Petersburg State University ; University of Hamburg, Saint Petersburg, Russia ; Hamburg, 133 pp.

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Abstract

The synoptic variability of flows in general and particularly in the Laptev Sea is not studied well enough by now. Considering the subject of the study to be the synoptic scale volatility of flows in the Laptev Sea we take into account characteristic for the Laptev Sea water mass movements, described by the statistical characteristics and understand by the synoptic scale heterogeneities in oceanographic fields, having characteristic temporal and spatial scales with a range of several days to months, and from tens to thousands of kilometers respectively (Monin, 1972; Kamenkovich et al, 1987; Lappo and Gulev, 1990).
A variability of the statistic characteristics of current oscillations are estimated and described.
The main source of information about the sea currents nowadays are the data from long - time measurements of their velocity and direction in definite sites of the sea on different depth horizons on the mooring stations with the use of ADCP (i.e. full-scale data on currents). Still even ADCP stations have some shortcomings in data sampling.
More than thirty years ago at a meeting devoted to finding new directions for Arctic biological oceanography, it was suggested that marine mammals might some day be used as "educated" oceanographic sampling platforms (Thomas J.Smith, 2001). They are "educated" because, through millions of years of evolution, they have developed the ability to find and consume such prey as the arctic cod, Boreogadus saida, keystone prey species (Paine, 1966) arctic species that to this day has largely eluded the efforts of scientists who have tried to study it (Welch et al., 1993).
Cetaceans, especially beluga whale (Delphinapterus leucas), display numerous anatomic and physiologic adaptations to life in a dense, three-dimensional medium. An exploration of cetacean ways helps in understanding how habitat influences habits and how cetaceans select habitat and what determines their summer distribution (Wursig B., 1989). Beluga whales are known to perform seasonal migrations, although the migration paths of the animals inhabiting different seas have been poorly studied.
It still remains unclear what environmental factors drive beluga whale distribution at both large and small scales in the Arctic and particularly, in the Laptev Sea. The population structure of this species is also very little known. Ecological theory of species distribution assumes that species distributions are determined at least in part by environmental variables (Austin, 2007). Study of the conditions of suitability for habitat use requires the analysis of flow volatility regime, as water dynamics as well as bathymetry and topography clearly play a role in the distribution of cetaceans; however it seems that this influence is more of a secondary effect.Distribution patterns often exhibit a hierarchical structure for determining the influencing factor (Redfern et al, 2006).
This thesis is aimed to study a synoptic-scale volatility of flow in ice-free period when beluga whales are seen to come to the Laptev Sea (Belikov A., Boltunov S., 2002) and characterize the adaptive distribution behaviour of white whales as a future oceanographic platform for studies in the areas of this kind, characterized by extreme cold temperatures, ice and strong seasonal variability and in this way difficult for investigations. Characteristics of the key habitat descriptors on a local scale are derived as a result of the analysis of various important publications of beluga from different areas of its habitat.
This thesis described important spatial patterns of distribution behaviour and attempted to elucidate its underlying causes as beluga whale occurence was set in relation to the Laptev Sea environment.

Document Type: Thesis (Master thesis)
Thesis Advisors: Siebert, Ursula and Glazov, Dmitry
Keywords: Ocean circulation; Water flow; Laptev Sea; Hydrography; Beluga whale; Delphinapterus leucas
Research affiliation: Kiel University
Projects: POMOR
Date Deposited: 06 Mar 2015 08:48
Last Modified: 06 Mar 2015 08:48
URI: http://oceanrep.geomar.de/id/eprint/27878

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