Understanding the movement and feeding habits of marine animals is crucial when
managing their populations. The molecular, and stable carbon isotope composition of
fatty acids from an organism provides time-integrated information on its dietary intake.
Hence, when spatial differences in the quality of seston exist it should be able to trace
these differences up into higher trophic level organisms. The presented study evaluates
the applicability of 13C/12C ratios of individual fatty acids, as natural tags and dietary
markers in marine pelagic organisms. In addition, the use of 13C/12C ratios of bulk
sample, as well as fatty acid composition data in examining the movement, and diet of
animals are further explored.
Samples of particulate organic matter, zooplankton, larval fish and juvenile salmon collected during three cruises off the west coast of Vancouver Island were analyzed. The
fatty acid composition, stable carbon isotope ratio of either bulk sample, or individual
fatty acids could typically distinguish samples collected in continental shelf waters from
off-shelf samples. The differences in fatty acid composition between the adjoining food
webs seem to be mainly caused by the different contribution of diatom-derived material
to the base of the food web. The higher 13C/12C ratios found in the diatom-richer seston in
shelf waters were not simply caused by the higher contribution of diatoms. Instead, stable
carbon isotope data on individual fatty acids indicate that growth conditions favouring
diatom growth caused 13C-enrichment in algae other than diatoms as well.
The relative abundance of polyunsaturated fatty acids, such as docosahexaenoic acid (22:6n-3), were found to increase with trophic level. Whereas the abundance of saturated, and monounsaturated fatty acids was higher in organisms from lower trophic levels. This suggests that the fatty acid composition may be a useful trophic level indicator. However, literature data indicate that these trends observed in seston. zooplankton, larval fish and juvenile salmon, do not hold for larger organisms and adult life stages. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/8043 |
| Date | 01 May 2017 |
| Creators | Veefkind, Ruben Jelmar |
| Contributors | Whiticar, Michael J. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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