Functional diversity and nutritional content in a deep-sea faunal assemblage through total lipid, lipid class, and fatty acid analyses

Abstract

Lipids are key compounds in marine ecosystems being involved in organism growth, reproduction, and survival. Despite their biological significance and ease of measurement, the use of lipids in deep-sea studies is limited, as is our understanding of energy and nutrient flows in the deep ocean. Here, a comprehensive analysis of total lipid content, and lipid class and fatty acid composition, was used to explore functional diversity and nutritional content within a deep-sea faunal assemblage comprising 139 species from 8 phyla, including the Chordata, Arthropoda, and Cnidaria. A wide range of total lipid content and lipid class composition suggested a diversified set of energy allocation strategies across taxa. Overall, phospholipid was the dominant lipid class. While triacylglycerol was present in most taxa as the main form of energy storage, a few crustaceans, fish, jellyfishes, and corals had higher levels of wax esters/steryl esters instead. Type and amount of energy reserves may reflect dietary sources and environmental conditions for certain deep-sea taxa. Conversely, the composition of fatty acids was less diverse than that of lipid class composition, and large proportions of unsaturated fatty acids were detected, consistent with the growing literature on cold-water species. In addition, levels of unsaturation increased with depth, likely suggesting an adaptive strategy to maintain normal membrane structure and function in species found in deeper waters. Although proportions of n-3 fatty acids were high across all phyla, representatives of the Chordata and Arthropoda were the main reservoirs of these essential nutrients, thus suggesting health benefits to their consumers.

Large-Scale Evaluation of Major Soluble Macromolecular Components of Fish Muscle from a Conventional 1H-NMR Spectral Database

“…Compared with those in Chondrichthyes, the relative intensity of the lipid-like component Macro 1 was higher, while those of the collagen-like component Macro 2 was lower in Actinopterygii. This result is consistent with previous studies regarding the distribution of lipids and proteins in fish [19][20][21]. The muscle tissue of Chondrichthyes is characterized by higher collagen and lower fatty acids compared with those of Actinopterygii.…”

Growth, health and biochemical composition of the sea cucumber Cucumaria frondosa after multi-year holding in effluent waters of land-based salmon culture

“…The variability of TAG likely reflects the different energy allocation strategies, i.e. how energy is distributed towards growth, survival and reproduction (Parzanini et al 2018). For example, the proportion of TAG displayed increasing trends in the prespawning period, and declined in ovaries of C. frondosa post spawning (Verkaik et al 2016, Gianasi et al 2017.…”

Reviews and syntheses: Insights into deep-sea food webs and global environmental gradients revealed by stable isotopes (δ<sup>15</sup>N, δ<sup>13</sup>C) and fatty acids trophic biomarkers

“…Trends in the isotopic and FA composition of deep-sea organisms were also seen along a depth gradient. As a proxy for water temperature as well as nutrient supply, depth may influence biochemical composition of marine consumers (Parzanini et al, 2018a(Parzanini et al, , 2018b. POM becomes more isotopically enriched while sinking to deeper depth due to microbial degradation (Altabet et al, 1999).…”

“…pelagic, demersal, and benthic, as diversely dependant on POM. Furthermore, as both isotopic and lipid composition of POM and as deep-sea taxa varied along a depth gradient in the deep North Pacific (Lewis, 1967;Altabet et al, 1999), North Atlantic (Polunin et al, 2001;Parzanini et al, 2018aParzanini et al, , 2018bParzanini et al, , 2017 and Arctic Ocean (Bergmann et al, 2008), we hypothesized that similar trends could be extended to the global scale.…”

“…Likewise, deep-sea species may exhibit different lipid and FA compositions along a bathymetric gradient, reflecting physiological adaptations to changing temperature and pressure with depth (Parzanini et al, 2018b).…”