δ¹³C values of lipids from phototrophic zone microplankton and bathypelagic shrimps at the Azores sector of the Mid-Atlantic Ridge

Pond, D.W., Sargent, J.R., Fallick, A.E., Allen, C., Bell, M.V. and Dixon, D.R. (2000) δ¹³C values of lipids from phototrophic zone microplankton and bathypelagic shrimps at the Azores sector of the Mid-Atlantic Ridge. Deep-Sea Research Part I: Oceanographic Research Papers, 47(1), pp. 121-136. (doi: 10.1016/S0967-0637(99)00050-3)

Abstract

The lipid composition and δ¹³C values of phototrophic zone microplankton, and species of bathypelagic shrimp that are not associated with hydrothermal vents, were determined for samples collected from the water column above the Mid-Atlantic Ridge. These analyses were compared with similar previously published data for vent bresiliid shrimp to address the hypothesis that deep-sea hydrothermal vent ecosystems are reliant on specific dietary nutrients produced by photosynthetic organisms. Microplankton ( < 200 mu m) sampled from the surface layer (similar to 4 m deep) and from the region of maximum light scattering (LSM, 48-75 m deep) were analysed to determine δ¹³C values of individual fatty acids in particulate matter. The distributions of fatty acids in total lipid from the surface layer and from the LSM were very similar, with high levels (similar to 45% of the total) of saturated fatty acids, particularly 14 : 0, 16 : 0 and 18 : 0, and moderate amounts (similar to 31% of the total) of polyunsaturated fatty acids (PUFA), dominated by 22:6(n-3). δ¹³C values of fatty acids from the surface layer and LSM were also very similar (mean values of -27.6 and -28.8 parts per thousand respectively), with a range of values from -25.0 to -32.2 parts per thousand, and PUFA being somewhat depleted in ¹³C relative to saturated and monounsaturated saturated fatty acids. Total lipid of abdominal muscle from three species of bathypelagic decapod shrimp, Ephyrina bidentata, Parapasiphaea sulcatifrons and Sergia japonicus collected from 2000 m contained is. 1(n-9), 16:0, 22:6(n-3) and 20:5(n-3) as major fatty acids in all cases. The fatty acids in total lipid from the wax ester-rich hepatopancreas of all three shrimps were dominated (similar to 50% of the total) by 18 : 1(n-9) and contained substantially lower levels of PUFA than muscle lipid. Total lipids from the hepatopancreas of E. bidentata and S. japonicus contained high levels of 22: 1 alcohols and 16:0 alcohol, respectively, whereas total hepatopancreatic lipid from P. sulcatifrons contained mainly 18 : 1 alcohols and 16 :0 alcohol. δ¹³C values for the fatty acids in the three species ranged from -22.4 to -30.7 parts per thousand for muscle (mean value -25.7 parts per thousand) and from -23.9 to -31.9 parts per thousand for hepatopancreas (mean value -26.1 parts per thousand), with PUFA again being depleted in ¹³C relative to saturated and monounsaturated fatty acids. δ¹³C values for the fatty alcohols in the three species ranged from -25.7 to -29.5 parts per thousand (mean value -27.1 parts per thousand). These lipid analytical and δ¹³C data are consistent with PUFAs in bathypelagic shrimps originating unmodified from PUFAs in the photic zone and wax eaters in bathypelagic shrimps originating substantially from animal biosynthetic activity.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fallick, Professor Anthony
• Authors: Pond, D.W., Sargent, J.R., Fallick, A.E., Allen, C., Bell, M.V., and Dixon, D.R.
• Subjects: Q Science > QD Chemistry; Q Science > QL Zoology
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Deep-Sea Research Part I: Oceanographic Research Papers
• ISSN: 0967-0637