Polar snow algae as a valuable source of lipids?

Author's accepted version (post-print).Available from 28/03/2019.Microalgae offer excellent opportunities for producing food and fuel commodities, but in colder climates the low growth rates of many varieties may hamper production. In this work, extremophilic Arctic microalgae were tested to establish whether satisfactory growth and lipid production could be obtained at low water temperature. Five species of snow/soil algae originating from Svalbard (78–79°N) were cultivated at 6 °C, reaching high cell densities (maximum dry weight 3.4 g·L−1) in batch cultivations, and high productivity (maximum 0.63 g·L−1·d−1). After 20 days of cultivation total lipids ranged from 28% to 39% of the dry weight, and diverse patterns of neutral lipid (triacylglycerol; TAG) accumulation were observed. The five species largely accumulated unsaturated fatty acyl chains in neutral lipids, especially polyunsaturated C16 series fatty acids, C18:1n-9 and C18:3n-3. The results indicate that polar microalgae could provide an opportunity to increase the yields of microalgal biomass and oil products at low temperatures.acceptedVersio

Remote sensing of zooplankton swarms

Zooplankton provide the key link between primary production and higher levels of the marine food web and they play an important role in mediating carbon sequestration in the ocean. All commercially harvested fish species depend on zooplankton populations. However, spatio-temporal distributions of zooplankton are notoriously difficult to quantify from ships. We know that zooplankton can form large aggregations that visibly change the color of the sea, but the scale and mechanisms producing these features are poorly known. Here we show that large surface patches (>1000 km 2 ) of the red colored copepod Calanus finmarchicus can be identified from satellite observations of ocean color. Such observations provide the most comprehensive view of the distribution of a zooplankton species to date, and alter our understanding of the behavior of this key zooplankton species. Moreover, our findings suggest that high concentrations of astaxanthin-rich zooplankton can degrade the performance of standard blue-green reflectance ratio algorithms in operational use for retrieving chlorophyll concentrations from ocean color remote sensing.publishedVersio

Mechanical processing of Phaeodactylum tricornutum and Tetraselmis chui biomass affects phenolic and antioxidant compound availability, nutrient digestibility and deposition of carotenoids in Atlantic salmon

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Data sheets aiding identification of phytoplankton carotenoids and chlorophylls

9 pagesSince the publication of 47 key phytoplankton pigment data sheets in the volume by Jeffrey et al. (1997b), several new algal groups and pigments have been reported. To reflect this and the increased use of mass spectrometry for phytoplankton pigment characterisation we have compiled revised and expanded data sheets documenting 47 carotenoids and 21 chlorophylls. These new data sheets complement the ones produced for the 1997 volume. They are also available online, at www.cambridge.org/phytoplankton, for ease of consultation. We do not include data sheets for the many chlorophyll transformation products found particularly in sediments; for information on these pigments readers should refer to the comprehensive review by Keely (2006). Similarly, our coverage of pigments contained in phototrophic bacteria is limited mostly to cyanobacteria found in the water column of freshwater and marine environments (see Chapter 1, this volume), hence we exclude the newly discovered chlorophyll f in stromatolites (Chen et al., 2010). Readers interested in anoxygenic phototrophic bacteria should consult the reviews by Takaichi (1999) and Scheer (2006)N

Does egg carotenoid improve larval quality in Arctic charr (Salvelinus alpinus)?

Females in mutually ornamented species are often less conspicuously ornamented than their male conspecifics. It has been hypothesized that offspring quality may de-crease if females invest more resources into ornaments at the expense of resources in eggs. An experiment was carried out to test whether natural variation in carotenoid in the eggs from a wild population of Arctic charr (Salvelinus alpinus) was associated with survival and growth of their offspring until hatching. Wild Arctic charr were caught at a spawning ground during the spawning period. Eggs from two different females, one female with yellowish carotenoid- rich eggs and one with paler eggs, were fertilized by sperm from the same male. This was repeated until gametes were collected from 42 females and 21 males, giving a total of 21 groups. After fertilization, the zygotes from each of the two females were reared in four replicated groups. These 168 groups were reared separately until hatching when the surviving larvae were counted and their body length measured. For the two response variables survival and body length at hatching, no effect was demonstrated of any of the predictors (i) amount of ca-rotenoid in the unfertilized eggs, (ii) the mothers' body condition, or (iii) ornament intensity of their red carotenoid- based abdominal ornament. Thus, this study gives no support for the hypothesis that females investing less carotenoid into their eggs suf-fer from decreased offspring quality until hatching. This lack of association between female ornament intensity and their fitness is not as expected if female ornaments evolved due to direct sexual selection from males on the more ornamented females (“direct selection hypothesis”)

Sex-specific seasonal variation in the carotenoid content of sea urchin gonads

This study documents the effect of sex on gonad carotenoid content during the annual reproductive cycle of Strongylocentrotus droebachiensis from northern Norway. Male and female S. droebachiensis exhibited distinctly different patterns of carotenoid variation, with seasonal carotenoid depletion and replenishment in females and carotenoid retention in males. Females lost approximately 71.1% of their echinenone during spawning, and compensated for the loss by active deposition during gonad regrowth. Female carotenoid levels (100 to 275 μg g–1 dry mass), although lower and less variable than male carotenoid levels, were consistently higher than predicted by estimates based on a constant post-spawning carotenoid content. Males did not lose carotenoids during spawning, and the concentration of carotenoids in male gonads varied from >600 to <200 μg g–1 dry mass, apparently as a passive result of increasing gonad size. The results suggest that carotenoid supplements in urchin diets would be largely wasted in gonad enhancement cultivation of male S. droebachiensis, and emphasize the importance of controlling future feeding trials for the confounding effect of sex on carotenoid deposition

Algal carotenoids. Part 64. Structure and chemistry of 4-keto-19'-hexanoyloxyfucoxanthin with a novel carotenoid end group

8 pages, 2 figures, 5 schemes.The structural elucidation of a new carotenoid 4-keto-19-hexanoyloxyfucoxanthin 5 from Emiliania huxleyi is documented by chromatographic (HPLC, TLC), spectroscopic (VIS, EIMS, FABMS, FABMSMS, 2D 1H NMR) and chemical evidence. The novel carotenoid end group exhibits particular spectroscopic and chemical properties. In particular the reactions with base and acid are investigated.Due to a very weak molecular ion upon electron impact and facile cleavage to paracentrone 20 related fragments, the new carotenoid was previously misidentified as 19-hexanoyloxyparacentrone 3-acetate 8, also found in other prymnesiophytes (haptophytes).This novel carotenoid readily undergoes cleavage to a C31-skeletal paracentrone 20 related product upon storage, preferably in methanol solution.The new end group represents a plausible precursor for C31-skeletal methyl ketone apocarotenoid metabolites in animals, and differs from the previously suggested precursor.E. S. E. was supported by a research grant from Hoffmann- La Roche, Basel, to S. L.-J.Peer reviewe

Corrigendum to “Polar snow algae as a valuable source of lipids?” [Bioresour. Technol. 235 (2017) 338–347](S096085241730411X)(10.1016/j.biortech.2017.03.130)

The authors regret that in the original version of this article, the culture collection strain ID numbers of the microalgae given in materials and methods Table 1 were not correctly assigned to the species names. The following revised Table 1 provides the correct strain ID numbers and information. The authors take the opportunity to note that the taxonomy of some of these strains is still under review (see “cf.” in Table 1). Recently, discussions have arisen regarding the correct taxonomy of CCCryo 194-04 (pers. comm. T. Leya, curator of CCCryo). Kawasaki et al. (2015) have recently revised several coccalean, oil-producing green algae and have assigned CCCryo 340b-08 (which is the same species as CCCryo 194-04) to the genus Macrochloris. On the other hand, it is currently being evaluated whether CCCryo 194-04 should be assigned to a different, still to be erected and published species within the genus Pleurastrum. The true taxonomy (and names) of some strains thus remain unclear at this time, and so the strain ID numbers containing the collection acronym listed above should be used to identify the microalgae used in this work. The authors would like to apologise for any inconvenience caused.</p