Structure of some intact lipids of petrel stomach oils

Abstract

The stomach or proventricular oils from 16 species of petrel have been analyzed and the carbon number distributions of the wax esters, triglycerides, and diacylglyceryl ethers are reported. The wax esters have been fractionated further into less and more polar species. To determine whether any intermolecular specificity existed, carbon number distributions for each lipid class were calculated, assuming random esterifications. The tirglyceride and diacylglyceryl ether compositions observed were all found to aggree closely with those calculated. The wax esters from three petrel species were found to have greater proportions of the middle range species with carbon numbers 34-38 than calculated. However, most of the lipids examined had random structures which have been found to be characteristic of marine sources. The results in general support the belief that the oils are derived directly from dietary sources rather than synthesis by the proventricular glands.

Evaluation of Mumiyo Deposits From East Antarctica as Archives for the Late Quaternary Environmental and Climatic History

“…Changes in the proportion of isoprenoid FAs could be an alternative indicator for food composition of snow petrels and may reflect relative changes in the proportion of krill feeding. For example, different FA patterns (e.g., ratio of C 18 to C 16 compounds) in snow petrel stomach oil from birds living at Cape Hallet, Northern Victoria Land (Watts & Warham, ) compared to mumiyo from DML (this study and Aiello et al, ; Figure ) may reflect the different prey composition of snow petrels feeding over the continental shelf in the Ross Sea (Ainley et al, ) compared to feeding over the deep ocean in DML, where the shelf is very narrow (Ainley et al, ). The differences within the Holocene to >58‐ka samples from DML are smaller than those to the Northern Victoria Land stomach oils further highlighting the possibility of regional differences in diet (Figure ).…”

“…The mumiyo has lower proportions of C 18 and higher proportions of C 16 and C 14 compounds than fresh stomach oils. The ratio of C 18 /C 16 compounds in mumiyo ranges from 0.2 to 0.5 and is higher in stomach oils of snow petrels (~2.7; Watts & Warham, ) and other procellariiform birds (e.g., 2.3 for Halobaena caerulea ; Connan et al, ). Although these differences might reflect a diet specific to DML, the FA patterns of organisms snow petrels generally feed on show higher C 18 /C 16 ratios as well (1.0 for Euphausia superba , 0.9 to 1.9 for Electrona antarctica , 2.9 for Gonatus antarcticus ; Lea et al, ; Phleger et al, , ; Phillips et al, ).…”

Summer sea-ice variability on the Antarctic margin during the last glacial period reconstructed from snow petrel (Pagodroma nivea) stomach-oil deposits

“…The lower contributions of polyunsaturated (<1%) and monounsaturated fatty acids (e.g. C18:1 9 ± 2%, C16:1 2.6 ± 0.3%) than in fresh stomach oil of other procellariiform seabirds (Connan et al, 2007) including snow petrels (Warham et al, 1976;Watts and Warham, 1976) could indicate post-depositional oxidation (Berg et al, 2019). However, similar fatty acid contributions to WMM7 have been recorded in a late Holocene DML stomach-oil deposit (Aiello et al, 2011), in prey of snow petrels (Cripps et al, 1999) and in stomach oils from other Procellariiformes (Wang et al, 2007).…”

“…These trips may be for several days (Barbraud et al, 1999). During this time, the snow petrel concentrates the lipid components of their prey into stomach oil; this provides an energy-rich food source for their chicks (Warham, 1977;Watts and Warham, 1976), and can be spat in defence against predators, or against other snow petrels in disputes over access to suitable crevices for nesting. Unlike muscle, feather or adipose tissues, which involve biosynthesis (e.g.…”

“…Unlike muscle, feather or adipose tissues, which involve biosynthesis (e.g. Rau et al, 1992), the basic biochemical composition of the prey is not altered during stomach oil formation (Watts and Warham, 1976). Thus, the stomach-oil deposits provide a window into the biochemistry of the prey consumed by snow petrels in open waters at the margins of, or within, the sea-ice zone.…”