Utilizing fatty acids as dietary indicators : lab trials and field applications /
Fatty acids are increasingly used as dietary indicators in marine ecosystems, and their application requires a basic understanding of the timing and scope of dietary modification of consumer tissues. Here, effects of diet upon polyunsaturated fatty acids (PUFAs) of marine microinvertebrates and est...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2004.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=766020751&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Fatty acids are increasingly used as dietary indicators in marine ecosystems, and their application requires a basic understanding of the timing and scope of dietary modification of consumer tissues. Here, effects of diet upon polyunsaturated fatty acids (PUFAs) of marine microinvertebrates and estuarine and marine fishes were investigated. Five experiments were conducted to determine the timing and extent of PUFA transfer in rotifer (Brachionus plicatilis), Artemia (Artemia franciscana), juvenile red drum (Sciaenops ocellatus), and larval and juvenile cobia (Rachycentron canadum). These organisms significantly modified dietary PUFAs within 1-3 days with over 90% incorporation of dietary PUFAs within several days. Results demonstrate that PUFAs are transferred throughout lower levels of marine food chains more quickly and efficiently than once believed and, therefore, may be useful in retrospective examinations of recent trophic relationships in marine ecosystems. In addition, no ontogenetic effect upon PUFAs was detected in the present studies even though teleost larvae typically undergo extensive developmental metamorphosis. To apply these findings, PUFAs were used as dietary indicators to retrospectively assess dietary interactions among Sargassum community flora and fauna in the western Gulf of Mexico. Spatial and temporal variability in PUFA signatures of selected taxa (Sargassum fluitans [autotroph], Leander tenuicornis [primary heterotroph], Balistes capriscus [secondary heterotroph]) was examined to quantify natural variation within these dietary tracers. Although PUFAs varied seasonally for all three taxa, no differences were detected between samples collected in 2000 and 2001 or from different sample locations in the northwest Gulf. High concentrations of PUFAs including 20:5n-3 and 22:6n-3 found in phytoplankton (based on signature of particulate organic matter) more closely match levels in higher trophic groups of the Sargassum community than signatures of other autotrophs (Sargassum fluitans, S. natans, or Cladophora sp.), suggesting that phytoplankton is the major source of organic matter entering this food web. Feeding ecology of the majority of juvenile and adult fishes in the complex are highly similar to available prey taxa and thus utilization of Sargassum mats is in part linked to their value as feeding grounds, although they do not appear to directly contribute organic matter to the system. |
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| Item Description: | Vita. "Major Subject: Wildlife and Fisheries Sciences". |
| Physical Description: | xvi, 154 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 135-153). |