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The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the “WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments” published in Wilderness & Environmental Medicine 2014; 25:41–49.

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The presence of distinct pigments is characteristic of different algal groups while the relative concentration of these pigments may vary with light conditions. Here we investigate the pigment pattern of 35 strains of Chrysophyceae by means of high-performance liquid chromatography. We further investigated shifts in pigment concentrations between light and dark conditions and the conservation of these pigment patterns in heterotrophic, mixotrophic, and phototrophic taxa. We did not find chlorophyll in heterotrophic strains but carotenoids were present in all taxa. In phototrophs and mixotrophs, we confirm the presence of the chlorophylls-a, c1, and c2 as well as of fucoxanthin. We provide evidence for the violaxanthin cycle as the dominant xanthophyll cycle. Moreover, we found pigments of the diadinoxanthin cycle in low concentrations. While pigment concentrations were regulated depending on light availability in photosynthetic taxa, they were unaffected by light in heterotrophic taxa.

Long-chain (>= C-20) polyunsaturated fatty acids (LC-PUFAs) are physiologically important fatty acids for most animals, including humans. Although most LC-PUFA production occurs in aquatic primary producers such as microalgae, recent research indicates the ability of certain groups of (mainly marine) invertebrates for endogenous LC-PUFA biosynthesis and/or bioconversion from dietary precursors. The genetic pathways for and mechanisms behind LC-PUFA biosynthesis remain unknown in many invertebrates to date, especially in non-model species. However, the numerous genomic and transcriptomic resources currently available can contribute to our knowledge of the LC-PUFA biosynthetic capabilities of metazoans. Within our previously generated transcriptome of the benthic harpacticoid copepod Platychelipus littoralis, we detected expression of one methyl-end desaturase, one front-end desaturase, and seven elongases, key enzymes responsible for LC-PUFA biosynthesis. To demonstrate their functionality, we characterized eight of them using heterologous expression in yeast. The P. littoralis methyl-end desaturase has Delta 15/17/19 desaturation activity, enabling biosynthesis of alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid (DHA) from 18:2 n-6, 20:4 n-6 and 22:5 n-6, respectively. Its front-end desaturase has Delta 4 desaturation activity from 22:5 n-3 to DHA, implying that P. littoralis has multiple pathways to produce this physiologically important fatty acid. All studied P. littoralis elongases possess varying degrees of elongation activity for saturated and unsaturated fatty acids, producing aliphatic hydrocarbon chains with lengths of up to 30 carbons. Our investigation revealed a functionally diverse range of fatty acid biosynthesis genes in copepods, which highlights the need to scrutinize the role that primary consumers could perform in providing essential nutrients to upper trophic levels.

In the light of the current biodiversity crisis that affects in particular freshwater ecosystems, it is crucial to understand the effects of functional diversity loss on phytoplankton-zooplankton interactions in freshwater food webs. Here, we simulated the loss of phytoplankton trait diversity by applying different intensities of mechanical disturbance to a natural phytoplankton community in a laboratory experiment. Different disturbance regimes clearly affected the trait distribution and functional diversity of these phytoplankton communities. In the experiment’s second phase, these altered communities were provided as a food source to the zooplankton grazers Daphnia longispina and Eudiaptomus graciloides and their life-history traits and lipid compositions were investigated. Both zooplankton fitness and reproductive success were affected differently, depending on the grazers’ feeding modes. Phytoplankton fatty acid composition was generally reflected in the consumers’ tissue. Nevertheless, some selective PUFAs accumulation occurred and mismatches in some fatty acids suggested a possible enzymatic modification of dietary fatty acids adopted to face biochemical deficiencies of the diets. Overall, this study highlights how a loss of specific traits in resource communities could impact consumer communities, and shows how these altered community traits may affect food web dynamics.

Lipids and fatty acids are key dietary components for the nutrition of organisms at all trophic levels. They are required to build cellular structures, such as cell membranes, serve as energy storage and are taking part in signal transduction cascades. For decades, ecological research investigated how dietary fatty acid availability contributes to the fitness of individuals and their populations. The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) found particular interest, as its dietary availability determines the fitness of many aquatic consumers. Due to the small body size of zooplankton, only bulk tissue fatty acid analysis was so far performed and thus the tissue-specific importance of EPA for zooplankton remained elusive. Here we used matrix-assisted laser desorption ionization – mass spectrometry imaging (MALDI-MSI) to reveal the tissue-specific distribution of functional phospholipids in the herbivorous zooplankton Daphnia magna. We demonstrate several lipid species for heart, eggs, gut, gonads, somatic and neurological tissues of D. magna, including the compound eye, as well as the optical and cerebral ganglion. The compound eye revealed a large diversity in EPA-containing lipid species, which were also found in other neurological tissues and the eggs. Such knowledge of tissue-specific fatty acid requirements is essential to investigate how selective allocation of dietary fatty acids within this key grazer on a functional and molecular level affects processes from the individual to food web scales. This methodological advancement will allow investigations on how invertebrates’ physiology and behaviour adjust to changing environmental conditions and potentially affect food web structures including the trophic transfer of dietary fatty acids.

Given the global loss of biodiversity, trait-based studies are needed to assess the associated consequences for ecosystem functions and services. Many studies focus on the assessment of functional diversity of natural communities as a mechanistic link between biodiversity and ecosystem functioning. In freshwater ecosystems, diversity of primary producers is crucial for resource use efficiency and trophic transfer of energy. Furthermore, one indicator of the ecological status of surface waters is the composition of natural phytoplankton communities. The number of available techniques for the quantification and discrimination of different phytoplankton groups have increased in recent years. For example, phytoplankton community composition can indirectly be assessed via CHEMTAX, a matrix factorization program, which calculates the contribution of different phytoplankton taxa to the total chlorophyll-a using concentrations of pigments analysed via liquid chromatography. A more direct, in vivo assessment can be achieved with instruments based on spectral fluorometry, such as the Algae Lab Analyser, which allows for a differentiation of four phytoplankton groups depending on spectral fluorescence signatures. In this study, we compared both methods by analyses of phytoplankton biomass and functional diversity from phytoplankton communities of three lakes of different trophic states, while a subset of biomass and diversity estimates derived from microscopic counts served as a reference. We found marked differences in biomass estimates of all assessed phytoplankton groups, with cyanobacteria being significantly underestimated by the Algae Lab Analyser. Furthermore, we show that the level of agreement between the methods somewhat depends on the trophic state of the lake. We conclude that both methods are suitable to estimate phytoplankton functional diversity with specific advantages and disadvantages. Here we provide users with a flow chart to help them find the most suitabl

The aquaculture production of pikeperch has reached commercial scale in a number of European countries, but the high mortality of early life cycle stages and minor understanding of nutritional requirements are still major bottlenecks. To investigate the fate of fatty acids during early development, weaning and rearing, pikeperch larvae and juveniles from a commercial recirculating aquaculture system (RAS) were sampled over 2 months for morphometric data, as well as fatty acid composition, with a total of 6 sampling days, with four to five replicates per sampling day and between 1 and 25 pikeperch larvae per individual sample, depending on larval biomass. The biomass of sampled pikeperch larvae varied from 0.1 to 420 mg (dry mass DM), depending on the age of the larvae, and the initial length of the pikeperch larvae was about 4.5 mm. Our data confirm that, accompanied by an exponential increase in dry mass, total fatty acids (TFAs) in larval tissues increased with the beginning of exogenous feed uptake and were depleted between days 13 and 25 post hatch, most likely associated with the weaning and metamorphosis of the larvae. We conclude that all fatty acid classes may serve as metabolic fuel during metamorphosis, but the ultimate fatty acid composition is strongly impacted by the available feed. The chosen diet probably caused a lack of alpha-linolenic (18:3n-3; ALA) and docosahexaenoic acid (22:6n-3; DHA) during larval development and a shortage of vaccenic (18:1n-7), alpha-linolenic (18:3n-3; ALA) and arachidonic acid (20:4n-6; ARA) in juvenile pikeperch. This led to low DHA/EPA ratios 13 days post hatch, a high EPA/ARA ratio at days 41 and 56 post hatch and a fluctuating ratio of alpha-linolenic acid to linoleic acid (18:2n-6; LA). A temporary lack of essential fatty acids can cause dysfunctions and eventually mortalities in pikeperch larvae and juveniles. Despite high larval growth rates, the biochemical composition of the first fed Artemia and microdiets was mo