Lipid and lipid carbon stable isotope composition of the hydrothermal vent shrimp Mirocaris fortunata:evidence for nutritional dependence on photosynthetically fixed carbon

Abstract

Mjrocaris fortunata were sampled from the Lucky Strike hydrothermal vent area (Eiffel Tower site) on the mid-Atlantic ridge during the French DlVA 2 cruise (June 1994). Small adults (17 to 22 mm total length), although morphologically identical, could be divided into 2 categones on the basis of pigmentat~on, llpid composition and I3C/l2c stable isotope ratios of fatty acids H~ghly pigmented small adults (8 6 to 9.2 pg carotenoid shrimp-') contamed higher levels of total lipid than similar-sized individuals containing lower levels of pigment (0.9 to 2 9 pg carotenoid shrimp-'). Lipid class analysis indicated that wax esters comprised 62.5% of total lipid in the former group. These p~gmented shrimp also contained high proportions of polyunsaturated fatty acids (PUFA), particularly the phototrophic microplanktonic markers 20:5(n-3) and 22:6(n-3) (14.0 and 33.5% respectively). By contrast small adults (22 mm) and adult shrimp (25 to 26 mm) with low levels of carotenoid pigmentation contained lower amounts of total lipid, little or no wax ester and low levels of 20:5(n-3) and 22:6(n-3), but did contain 16:2(n-4) and 18:2(n-4) and the non-methylene interrupted dienes 20:285,13 and 22:287,15. GC-IRMS analysis of all fatty acids and fatty alcohols in the pigmented small adults indicated 6I3C values of -18.2 to -27.7?&,, which is consistent with a photosynthetic carbon source for these compounds. The I3C/l2C Isotope composition of fatty acids from low-pigmented small adults and adults was more variable (-12 5 to -33.11:L) and suggests a bimodal distribution which may be attributable to differing nutritional sources or the physiological/reproductive status of these shnmp Samples of eggs, which are carried by the female on the pleopods, represented approximately 57 % of total somatic lipid which indicates a substantial reproductive investment by this species. The egg lipids comprised high proportions of triacylglycerols (64.4 to 78.0% of total I~pid) whilst the fatty acid composition was dominated by the monounsaturated fatty acids 16:l(n-71, 18:l(n-7) and 18:l(n-9). which accounted for 65.7 to 73.5"0 of total fatty acids. By contrast, PUFA were relatively minor components of egg lipids, particularly 20:5(n-3) and 22:6(n-3), which accounted for only 1.1 and 2.9% of total egg fatty acids respectively. This indicates that the reproductive investment by this species is supported mainly by material derived from bacterial chemosynthesis. The potential for M. fortunata hedge betting by producing larvae which either metamorphose at the vent site or adopt a bathypelagic lifestyle and delay metamorphosis to facilitate more widespread dispersal is discussed.

Acquisition of epibiotic bacteria along the life cycle of the hydrothermal shrimp Rimicaris exoculata

“…Only juveniles above 1.2 cm were collected at the aggregates' periphery and are orange (Komai and Segonzac, 2008). Wax esters, fatty acids and fatty alcohols found in the juveniles indicated that they might feed for extended periods in the euphotic zone, allowing dispersion (Pond et al, 1997). This was supported by genetic data that suggested high gene flow in R. exoculata populations (Teixeira et al, 2011).…”

Identification of food sources of invertebrates from the seagrass Zostera marina community using carbon and sulfur stable isotope ratio and fatty acid analyses

“…References: (1) Ackman et al (1968), (2) Gillian & Hogg (1984), (3) Findlay et al (1990), (4) Volkman et al (1980), (5) present study, (6) Kayama et al (1989), (7) Erwin (1973), (8) Sargent et al (1987), (9) Zhukova & Kharlamenko (1999), (10) Pond et al (1997), (11) Nichols et al (1986) Table 6. Fatty acids and fatty acid ratios that were used as markers for food sources in the Zostera marina ecosystem.…”

Prey base shifts in red rock lobster Jasus edwardsii in response to habitat conversion in Fiordland marine reserves: implications for effective spatial management

“…Palmitoleic acid (16:1ω7) has been employed widely as a specific biomarker for microbial activity, particularly chemoautotrophic production (MacAvoy et al 2002a,b) but it may also originate from diatoms (Lewis 1969, Pond et al 1998 or be biosynthesized from other compounds. The δ 13 C signature of 16:1ω7 from sulfur-oxidizing bacteria is typically in the range of -28 to -35 ‰, while 16:1ω7 sourced from phytoplankton is more 13 C enriched (Pond et al 1997). In the present study, we observed that 16:1ω7 from red rock lobster mussel tissue was relatively more depleted in 13 C in inner Doubtful Sound (δ 13 C -30.65 ± 1.40 ‰, mean ± SE) than at Te Awaatu Channel (δ 13 C -23.68 ± 0.57 ‰) and at Kuta Parera Reserve (δ 13 C -22.1 ‰).…”