Fatty acid trophic markers in the pelagic marine environment. Adv Mar Biol

University of Copenhagen, Danish Institute for Fisheries Research, Charlottenlund Castle, DK-2920 Charlottenlund, Denmark.
Advances in Marine Biology (Impact Factor: 5). 02/2003; 46:225-340. DOI: 10.1016/S0065-2881(03)46005-7
Source: PubMed

ABSTRACT Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers. To identify these fatty acid patterns the literature was surveyed and a partial least squares (PLS) regression analysis of the data was performed, validating the specificity of particular microalgal FATM. Microalgal group specific FATM have been traced in various primary consumers, particularly in herbivorous calanoid copepods, which accumulate large lipid reserves, and which dominate the zooplankton biomass in high latitude ecosystems. At higher trophic levels these markers of herbivory are obscured as the degree of carnivory increases, and as the fatty acids originate from a variety of dietary sources. Such differences are highlighted in a PLS regression analysis of fatty acid and fatty alcohol compositional data (the components of wax esters accumulated by many marine organisms) of key Arctic and Antarctic herbivorous, omnivorous and carnivorous copepod species. The analysis emphasizes how calanoid copepods separate from other copepods not only by their content of microalgal group specific FATM, but also by their large content of long-chain monounsaturated fatty acids and alcohols. These monounsaturates have been used to trace and resolve food web relationships in, for example, hyperiid amphipods, euphausiids and fish, which may consume large numbers of calanoid copepods. Results like these are extremely valuable for enabling the discrimination of specific prey species utilized by higher trophic level omnivores and carnivores without the employment of invasive techniques, and thereby for identifying the sources of energetic reserves. A conceptual model of the spatial and temporal dominance of group-specific primary producers, and hence the basic fatty acid patterns available to higher trophic levels is presented. The model is based on stratification, which acts on phytoplankton group dominance through the availability of light and nutrients. It predicts the seasonal and ecosystem specific contribution of diatom and flagellate/microbial loop FATM to food webs as a function of water column stability. Future prospects for the application of FATM in resolving dynamic ecosystem processes are assessed.

  • Source
    • "dinoflagellates and terrestrial run-off (Budge and Parrish 1998; Dalsgaard et al. 2003). These 98 biomarkers are conservatively transferred throughout the foodweb and indicate dietary sources in 99 both invertebrates and fish (Budge and Parrish 1999; Copeman et al. 2009; Kelly and Scheibling 100 2012; StJohn and Lund 1996). "
    [Show description] [Hide description]
    DESCRIPTION: Climate models indicate the Arctic will undergo dramatic environmental change with forecasted increases in temperature and river runoff. Saffron cod (Eleginus gracilis) is abundant in nearshore waters and appears in the diet of many Arctic sea birds and marine mammals, however, little is known about its early ecology and consequently how they might be affected by environmental changes. We aimed to characterize the mechanisms of spatial and ontogenetic variation in trophic biomarkers (lipid classes, fatty acids and bulk C and N stable isotopes) of saffron cod from the Western Arctic, Chukchi and Bering Seas. Size standardized analyses showed a significant difference in lipid condition metrics and trophic biomarkers as a function of survey location. Both ontogeny and sampling location played an important role in determining lipid stores with elevated levels in both small offshore juveniles (< 55 mm) and larger inshore juveniles (> 75 mm). Higher lipid storage in Arctic juveniles was associated with elevated levels of diatom fatty acid markers but not with near-shore carbon input. Increased lipids were found in age-1 juveniles from Prudhoe Bay in the Western Beaufort that fed at a lower trophic level then similarly sized age-0 juveniles from surface trawls in the Bering Sea. The use of otolith annuli reveal two discrete patterns of growth that help explain the trade-offs between energy storage and rapid growth that diverge between the Arctic and Bering Sea. Laboratory temperature-growth experiments confirmed that saffron cod have a eurythermal growth response and are able to store excess lipids at temperatures as high as 20 ºC.
  • Source
    • "Antarctic Micractinium strains well-documented (Dalsgaard et al. 2003; Osipova et al. 2009; Fogliano et al. 2010; Blanc et al. 2012; Boelen et al. 2013). Since these Antarctic Micractinium strains also showed a higher concentration of polyunsaturated fatty acids (PUFAs) and tolerance to lower temperatures, the microalgae could be a potential biological resource to produce compounds of biochemical interest such as omega-3 and omega-6 fatty acids. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cryotolerant eukaryotic microalgae were isolated from meltwater streams on Ardley Island and King George Island in Antarctica, and their morphological, molecular, and physiological characteristics were investigated. Owing to their simple morphology, distinctive characters were not observed with neither light microscopy nor transmission electron microscopy. However, molecular phylogenetic inferences drawn from the concatenated small subunit rRNA and internal transcribed spacer sequence data indicated that these microalgal strains belonged to the genus Micractinium. All the Micractinium strains showed cryotolerant properties, while their optimum growth temperature was around 20°C. Similar to other cryotolerant organisms, these Antarctic microalgae also contained a higher ratio of polyunsaturated fatty acids to saturated fatty acids. In this study, new Antarctic Micractinium spp. were discovered and added to the culture collection. These cryotolerant strains may serve as a promising source of nutritionally important linoleic (C18:2 ω6) and α-linolenic (C18:3 ω3) acids.
    Phycological Research 07/2015; 63(3). DOI:10.1111/pre.12097 · 1.27 Impact Factor
    • "Lipid biomarkers are a useful tool for studying the trophic ecology and determination of trophic relationships between species in aquatic communities (Piche et al. 2010; Budge et al. 2011). Fatty acid composition of organisms can be used to infer the dietary resources utilized by the consumer , as many of these fatty acids are transferred from prey to predators without modification (Dalsgaard et al. 2003). This approach is based on the assumption that many fatty acids in marine environments, particularly polyunsaturated fatty acids (PUFAs), can only be biosynthesized , mainly by phytoplankton, and become an essential dietary component for higher trophic levels. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Marine mollusks provide shelter to epibiotic organisms which settle on the outer surface of their hard shells. Epibionts can exert beneficial or detrimental effects on the host mollusk. In this study, the ecology of the association of the commercially valuable marine mobile scallop Patinopecten (=Mizuhopecten) yessoensis with its epibiotic barnacle Balanus rostratus was investigated. Fatty acid analysis was performed to determine the trophic relationships between these species. The distribution of fatty acid markers in this scallop species suggests an important contribution of diatoms, flagellates and animal material in its diet. The fatty acid analysis indicated a predominance of diatoms in the diet of the adult barnacles and some detrital input into the diets of young individuals. It was found that adult barnacles may compete with the scallops for food sources such as diatoms and zooplankton. It was revealed that with a negligible biomass of epibionts, the interactions between the barnacle and scallop may be regarded as commensalisms. An increase in the weight of epibiotic barnacles resulted in decreases in the weights and shell heights of the scallops, testifying to the adverse influence of a high biomass of epibionts on their host.
    Marine Ecology 07/2015; DOI:10.1111/maec.1226 · 1.84 Impact Factor
Show more