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Some sacoglossan sea slugs incorporate intracellular functional algal chloroplasts, a process termed kleptoplasty. "Stolen" chloroplasts (kleptoplasts) can remain photosynthetically active up to several months, contributing to animal nutrition. Whether this contribution occurs by means of translocation of photosynthesis-derived metabolites from functional kleptoplasts to the animal host or by simple digestion of such organelles remains controversial. Imaging of 13C and 15N assimilation over a 12-h incubation period of Elysia viridis sea slugs showed a light-dependent incorporation of carbon and nitrogen, observed first in digestive tubules and followed by a rapid accumulation into chloroplast-free organs. Furthermore, this work revealed the presence of 13C-labeled long-chain fatty acids (FA) typical of marine invertebrates, such as arachidonic (20:4n-6) and adrenic (22:4n-6) acids. The time frame and level of 13C- and 15N-labeling in chloroplast-free organs indicate that photosynthesis-derived primary metabolites were made available to the host through functional kleptoplasts. The presence of specific 13C-labeled long-chain FA, absent from E. viridis algal food, indicates animal based-elongation using kleptoplast-derived FA precursors. Finally, carbon and nitrogen were incorporated in organs and tissues involved in reproductive functions (albumin gland and gonadal follicles), implying a putative role of kleptoplast photosynthesis in the reproductive fitness of the animal host. [ABSTRACT FROM AUTHOR]

Abstract High moisture extrusion cooking is a well-established method to develop soy-based meat alternatives. Algae are increasingly researched into as an alternative protein source, particularly the micro-algae spirulina (Arthrospira platensis) is known for its high protein content. However, little is known how spirulina behaves during the extrusion process. This study investigates the sensory properties of spirulina (10%, 30% or 50%) and soy-based meat alternatives (16 samples) produced according to a Design of Experiment (DoE) with different levels of moisture (57%, 67% or 77%), screw speed (600 rpm, 900 rpm or 1200 rpm), temperature (140 °C, 160 °C or 180 °C) and two production days (independent replicates). Conventional profiling by a trained sensory panel (n = 12) based on a product-specific vocabulary was carried out and the samples were also subjected to instrumental texture profile analysis (TPA) and razor shear measurement (MORS). The data revealed that high spirulina content caused a black color, an intense flavor with earthy notes and an algae odor that is rather musty. Additionally, the higher the share of spirulina, the lower were the elasticity, fibrousness and firmness of extruded samples. High moisture content resulted in products evoking a juicy and soft mouthfeel plus a moist appearance. Instrumentally measured texture parameters matched with the sensory profile regarding texture: high moisture induces a decrease in shear force, shear energy, hardness, cohesion, springiness and chewiness. Particularly firmness perceived by the panel correlates with both MORS and TPA measurements while sensory elasticity correlates with springiness. When keeping moisture low, but screw speed and temperature high during extrusion, it is possible to partly substitute soy with spirulina in order to produce firm and fibrous products with a decent algae flavor that will contribute to shape a more sustainable future for food. Highlights • Spirulina is suitable to partly substitute soy in extruded meat alternatives as long as moisture is low. • Screw speed and temperature should be at high levels to support texture formation. • Content of spirulina and the amount of moisture have strongest impact on the sensory profile. • An increased amount of spirulina intensifies the earthy flavor and musty algae odor. • Spirulina cultivation will become resource-saving and support sustainable food choice. [ABSTRACT FROM AUTHOR]

Studies considering broodstock conditioning of Ruditapes decussatus mostly used flagellates and diatoms for feeding, mainly Isochrysis galbana and Chaetoceros calcitrans, respectively. The present study evaluated the effect of different microalgal diets on gonadic maturation of R. decussatus including three microalgae species (C. calcitrans, Tetraselmis suecica, and Nannochloropsis oculata) which were used to prepare six diets: three monospecific and three bispecific mixed diets at a proportion of 1:1. Clams were daily fed at a ratio of 1% dry weight of algae/live weight of clam and unfed treatment was used as control. Results showed that clams fed C. calcitrans alone or mixed with T. suecica attained earlier full maturity with the highest response to spawning induction (after 34 conditioning days) and largest proportion in the partial spawning phase for both, followed by T. suecica alone after 48 days. In contrast, N. oculata alone or mixed diets demonstrated poor performance for gonadal maturation. Unfed treatment did not show any sign of maturation. The results indicated that T. suecica has high conditioning potential like C. calcitrans and their mixture gave the highest benefit. Therefore, T. suecica can be recommended for R. decussatus broodstock conditioning. [ABSTRACT FROM AUTHOR]

This study compared the efficacy of different dietary algae on the growth and reproduction of the cyclopoid copepod Cyclopina kasignete, a potential live food species for fish larvae in aquaculture. The experimental diets for the copepod consisted of three monoalgal diets (Nannochloropsis oculata, Tisochrysis lutea and dry Melosira sp.) and two mixed algae diets (T. lutea + N. oculata, T. lutea + dry Melosira sp.). The experiment was carried out for 30 days, and the population growth, survival and reproductive performance (generation time, hatching rate, life spawning times, daily offspring production, eggs per sac, lifespan and sex ratio) were used to assess the responses of C. kasignete to different food types. Population growth, survival and reproductive capacities of C. kasignete were significantly affected by the mono and binary species of algal diets. The results showed that copepods exhibited superior growth, survival and productivity when fed on fresh T. lutea, dry Melosira sp. and a mixture of both species compared to other dietary treatments. Copepods produced comparable growth, survival and productivity when fed on diatoms (dry Melosira sp.) as a single or in combination with other algae. This study indicates that cyclopoid copepod C. kasignete grow fast and have the potential to serve as a live food for aquaculture. The algae T. lutea, dry Melosira sp. and their combination are appropriate food to sustain the growth and reproduction of this copepods in mass culture as a potential live food in fish hatchery. [ABSTRACT FROM AUTHOR]

The impact of titanium dioxide nanoparticles (nano-TiO2) on the bioavailability of metals in aquatic filter-feeding organisms has rarely been investigated, especially in the presence of algae as a food source. In this study, we quantified the accumulation and subcellular distribution of arsenate (AsV) in Daphnia magna in the presence of nano-TiO2 and a green alga (Scenedesmus obliquus) food source. Results showed that S. obliquus significantly increased the accumulation of total arsenic (As) and titanium (Ti) in D. magna. The presence of this food source increased As in metal-sensitive fractions (MSF) and as biologically detoxified metals (BDM), while it decreased Ti levels in MSF but increased levels as BDM. The difference in the subcellular distribution of As and Ti demonstrates the dissociation of As from nano-TiO2 during digestion at subcellular partitioning irrespective of food availability. In turn, the presence of algae was shown to increase metal-based toxicity in D. magna due to the transfer of As from BMD to MSF. Furthermore, S. obliquus significantly increased the concentration of As and Ti in soluble fractions, indicating that As and nano-TiO2 ingested by D. magna could be transferred more readily to their predators in the presence of S. obliquus. Our study shows the potential of algae to increase the toxicity and biomagnification of AsV. Furthermore, it highlights food as an important factor in the toxicity assessment of nanomaterials and co-existing pollutants. [ABSTRACT FROM AUTHOR]

The power of the sea has been known since ancient times and marine resources have even benefited mankind when technology was less developed. The use of these resources, both for health and nutritional purposes, is increasingly spreading to other fields today. Algae produce their own food and have a vital value for life. For this reason, these organic resources have great potential for use in many areas. They are mainly used for medical and food purposes, as fertilizer in agriculture and as a feed source for some animals. Their high levels of protein, vitamins and minerals make these living things valuable as an important source of energy. Containing omega-3 fatty acids, essential for nutrition and development for all living things, provides their usage as food and feed ingredients. In particular, the high amounts of lipid in some microalgae show promise in areas such as biofuels. This study focuses on the applications of algae based on nutritional and chemical value. [ABSTRACT FROM AUTHOR]

The industrial cultivation of microalgae can produce oil and protein rich biomass at areal yields higher than those of conventional agriculture. Given that algae has been demonstrated as both a potential biofuel and a food product, it is important to consider the environmental and economic tradeoffs associated with these uses. Here we evaluate the financial value of capital options for three processing strategies that produce food and fuel from algae. We show, in stochastic price regimes for production inputs and outputs, that the greatest returns are achieved when algal biomass is valorized as a high value fishmeal replacement. A co-production technology strategy that valorizes extracted oils as fuel and residual biomass as fishmeal replacement can enable the economic production of a renewable biofuel. Consistent with other studies, fuel-only production remains uneconomical, but becomes preferred if a low value commodity crop substitute is considered as the rendered food product. Potential improvements in capital and operational costs to enable economic production of fuel and low-value food are explored. Multimodal biorefineries ensure continued production during periods that are economically unfavorable with a single-mode approach, but have lower returns due to larger upfront capital investment. An analysis of a biorefinery with fuel, food, and coproduction modes demonstrated that mode selection was mostly influenced by output product prices when food and energy prices were competitive. Nitrogen fertilizer prices had a moderate influence on mode selection, while other inputs (phosphorus, electricity, natural gas) had negligible influence. The application of a carbon tax places a penalty on food production, but improves returns when renewable electricity is utilized in production. This analysis demonstrates an approach for evaluating financial tradeoffs at the food-energy nexus under uncertain market conditions. [ABSTRACT FROM AUTHOR]

Euglena gracilis Z is a micro-algae that is used as a food or nutritional supplement. Paramylon, the carbohydrate storage substance of Euglena gracilis Z has β-1, 3-glucan structure. Euglena gracilis Z and paramylon are reported to affect the immune system. In this study, we investigated the protective effects of Euglena gracilis Z and paramylon against influenza virus infection in mice. Euglena gracilis Z and paramylon were administered to mice as a 2% dietary mixture ad libitum . At 2 weeks after initiation of dietary administration, mice were infected intranasally with influenza virus A/PR/8/34 (H1N1). Survival rate was monitored 10 days after infection. In addition, we performed virus titer and cytokine profiles in the lung. High survival rates were observed for Euglena gracilis Z and paramylon-treated groups compared to the control group. Significantly lower virus titer in the lung was observed in the Euglena gracilis Z and paramylon-treated groups compared to the control group from day 1 after infection. Higher amount of IL-1β, IL-6, IL-12 (p70), IFN-γ, and IL-10 was observed in the paramylon groups compared to the control group. Our data therefore reveals a novel immunoregulatory role of the Euglena gracilis Z and paramylon which provides protection against influenza virus infection. [ABSTRACT FROM AUTHOR]

Daphnia in the natural environment experience fluctuations in algal food supply, with periods when algal populations bloom and seasons when Daphnia have very little algal food. Standardized chronic toxicity tests, used for ecological risk assessment, dictate that Daphnia must be fed up to 400 times more food than they would experience in the natural environment (outside of algal blooms) for a toxicity test to be valid. This disconnect can lead to underestimating the toxicity of a contaminant. We followed the growth, reproduction, and survival of Daphnia exposed to 75 and 200 µg/L silver nanoparticles (AgNPs) at 4 food rations for up to 99 d and found that AgNP exposure at low, environmentally relevant food rations increased the toxicity of AgNPs. Exposure to AgNP at low food rations decreased the survival and/or reproduction of individuals, with potential consequences for Daphnia populations (based on calculated specific population growth rates). We also found tentative evidence that a sublethal concentration of AgNPs (75 µg/L) caused Daphnia to alter energy allocation away from reproduction and toward survival and growth. The present findings emphasize the need to consider resource availability, and not just exposure, in the environment when estimating the effect of a toxicant. Environ Toxicol Chem 2017;36:3008-3018. © 2017 SETAC [ABSTRACT FROM AUTHOR]

Understanding the properties of a biomaterial such as seaweed is important for retaining product quality and improving shelf life through optimized post-harvest processing. An aquacultured sugar kelp ( Saccharina latissima ) was investigated to determine the effects of glass transition on the shrinkage of dried products. Freeze dried samples of varying moisture content were analyzed for glass transition and freezing point using a differential scanning calorimeter. An image processing algorithm was used for analyzing shrinkage while drying. Drying kinetics were studied at 40 and 70 °C, 10 m/s air velocity and at relative humidity of 25, 50 and 80%. When the drying temperature was 70 °C, above T g , the shrinkage rate was greater, exhibiting higher matrix mobility in the rubbery state. The glass transition, freezing lines and moisture sorption isotherm can be utilized to extend the shelf-life of both low and high moisture sugar kelp and provide guidelines for other species of seaweed. [ABSTRACT FROM AUTHOR]

Oyster refinement, a common practice in France, is aimed at increasing the weight of oyster tissue and influencing the taste properties of the refined oysters. Refinement usually takes place in land-based systems where the oysters are fed with relatively high concentrations of microalgae. In this study the impact of feeding Skeletonema costatum and Rhodomonas baltica on the biochemical composition and sensory characteristics of Pacific cupped oysters ( Crassostrea gigas ) from the Eastern Scheldt during land-based refinement was studied. After a feeding period of four and seven weeks market-sized oysters were sampled for the analysis of fatty acids, free amino acids and volatile organic compounds and for a sensory evaluation by consumers and an expert panel. The algae Skeletonema costatum showed a lower ∑ PUFA, ∑ n − 3, ∑ n − 6, C18:2n6, C18:3n3, C18:4n3, C22:6n3 content as compared with Rhodomonas baltica . These differences were also reflected in the fatty acid profile of the oysters fed with the corresponding algae diets. Furthermore, general linear model and principal component analysis showed marked differences in free amino acids and volatile organic compound content between Skeletonema , Rhodomonas fed oysters and reference oysters. For example, threonine, glutamine, leucine, histidine, (E)-2-hexenal, (E)-2octenal, (E)-2-octen-1-ol, (E,E)-2,4-octadien-1-ol, (E,Z)-3,6-nonadien-1-ol and (Z,E)-2,6-nonadienal contents were higher in Skeletonema fed oysters compared to Rhodomonas fed oysters. Sensory differences between the experimental oyster groups were shown. Skeletonema fed Pacific cupped oysters were characterized by a stronger seaweed flavor, higher perceived sweetness and a firmer texture in comparison with Rhodomonas fed oysters. Naïve consumers were only able to differentiate between Rhodomonas fed oysters and reference oysters. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of cell wall hardness and fish species on digestibility of unicellular sources. The gross composition, and the composition and cell wall hardness of the sources were determined for four sources. These were 3 microalgae species ( Chlorella vulgaris , Scenedesmus dimorphus and Nannochloropsis gaditana ) and a cyanobacterium ( Arthrospira maxima ). Apparent digestibility coefficients (ADCs) of their nutrients were determined in Nile tilapia and African catfish, at a 30% diet inclusion level. It was hypothesized that herbivores can access and thus digest unicellular proteins better than omnivores, and that the differences in protein digestion between the fish species increase with the robustness of the cell walls. Differences in cell wall hardness were quantified as the cells' resistance to mechanical shear. A . maxima was least resistant to shear: the time needed to disrupt 50% of the cells was 2 min compared to 24–33 min for the other sources. Differences were also measured in nutrient digestibility between the sources in both fish species. Contrary to the basal diet, which was digested differently between the fish species, there was no fish species effect on nutrient ADCs of the unicellular sources. A . maxima had the highest protein ADCs in both fish species (81.4–82.5%), followed by C . vulgaris (80.7–80.9%), N . gaditana (72.4–74.7%) and S . dimorphus (67.0–68.3%). Ingredient fat ADCs ranged between 65.1 and 89.1%. Unicellular non-starch polysaccharides (NSP), comprising the unicellular cell wall fraction, was not inert in both fish species (ADC > 46.0%), which was attributed to fermentation. The digestibility data suggest that the differences in nutrient accessibility of unicellular sources are dominant over the differences in digestive systems between herbivorous and omnivorous fish. Nevertheless, nutrient digestibility of the unicellular sources did not relate to the mechanical cell wall hardness. [ABSTRACT FROM AUTHOR]

Fish and seafood consumption are increasing worldwide and the contribution of aquaculture products to consumers' diets is significant. External feeding in aquaculture unlocks the possibility of tailoring fish products with health beneficial compounds. A study was undertaken to evaluate the feed fortification with an iodine-rich macroalgae ( Laminaria digitata ) and selenised yeast, at its maximum permitted levels, on minerals and vitamins content in rainbow trout edible part. Dietary supplementation resulted in a six-fold increase for iodine and a 2.9-fold increase for selenium contents in trout fillets without altering sensorial traits. The fortified fish presented a nutritional contribution of 12.5% DRI for iodine and 78% DRI for selenium, but all produced fish could supply 80% DRI for vitamin D 3 . Overall, fish from this trial could be labelled as “high in selenium and high in vitamin D 3 ” under the EFSA definition for a functional food. [ABSTRACT FROM AUTHOR]

This study explored Himanthalia elongata brown seaweed as a potential source of dietary fucoxanthin which is a promising medicinal and nutritional ingredient. The seaweed was extracted with low polarity solvents (n-hexane, diethyl ether, and chloroform) and the crude extract was purified with preparative thin layer chromatography (P-TLC). Identification, quantification and structure elucidation of purified compounds was performed by LC-DAD-ESI-MS and NMR ( 1 H and 13 C). P-TLC led purification yielded 18.6 mg/g fucoxanthin with 97% of purity based on the calibration curve, in single-step purification. LC-ESI-MS (parent ion at m/z 641 [M + H-H2O] + ) and NMR spectra confirmed that the purified band contained all-trans-fucoxanthin as the major compound. Purified fucoxanthin exhibited statistically similar (p > 0.05) DPPH scavenging capacity (EC 50 : 12.9 μg/mL) while the FRAP value (15.2 μg trolox equivalent) was recorded lower (p < 0.05) than the commercial fucoxanthin. The promising results of fucoxanthin purity, recovery and activity suggested that H. elongata seaweed has potential to be exploited as an alternate source for commercial fucoxanthin production. [ABSTRACT FROM AUTHOR]

The article discusses the properties of microalgae present in both marine and freshwater environments. Topics discussed include microalgae as human food source or nutritional supplements, concerns associated with consumption of microalgae, and the challenges for developing large-scale photobioreactors. It also explores safety and regulatory issues related to consumption of microalgae.

Sujiaonori, a river alga growing in the Kochi prefecture, Japan, contains several bioactive compounds such as sulfated polysaccharides (ulvans), ω-3 fatty acids, and vitamins. Dietary intake of this alga-based supplement has been reported to increase circulatory adiponectin, a salutary hormone that is reported to be associated with healthy longevity and prevents a number of cardiovascular and metabolic disorders. This report highlights the anti-allergic and skin health enhancing effects of Sujiaonori-derived ulvan (Tosalvan) and supplement, respectively. RBL-2H3 cell line was used to investigate the anti-allergic effect of algal SP through the evaluation of β-hexosaminidase activity. Algal sulfated polysaccharides or SP (Tosalvan, Yoshino SP) were extracted from powders of dried alga samples provided by local food manufacturers. Report on the effect of daily dietary intake of Sujiaonori-based supplement on skin health is part of a four-week clinical investigation that, in comparison with a supplement made of 70% corn starch powder and 30% spinach powder mixture (twice 3 g daily), explore the beneficial effects of Sujiaonori algal biomaterial (SBM; 3 g taken twice daily) on cardiovascular, gastrointestinal and skin health in a sample of Japanese women. Transepidermal water loss (TEWL) was the skin health marker used in this study and was measured with the use of a corneometer. Significant reduction of β-hexosaminidase activity was observed in Tosalvan and Yoshino SP-treated cells (vs. control; p < 0.05), whereas dietary intake of SBM markedly reduced TEWL level after four weeks of supplementation, as compared to baseline TEWL (p < 0.001). Additionally, SBM improved TEWL better than the control product (p < 0.001). Findings contained in this report suggest that Sujiaonori-derived Tosalvan and Yoshino SP have anti-allergic potential and that the dietary intake of SBM has a beneficial effect on skin health. [ABSTRACT FROM AUTHOR]

The supply of microalgae to hatcheries is a limiting factor for the mass larval production of sea cucumber ( Apostichopus japonicus) in Fujian Province, China. In this study, Nannochloropsis sp. isolated from the East China Sea was tested as food for A. japonicus larvae. The first trial compared the effect of mono-, bi- and trialgal diets comprising three microalgae ( Chaetoceros muelleri, Dunaliella tertiolecta and Nannochloropsis sp.) on A. japonicus larval growth, survival, settlement and juvenile growth. The results showed that there were no significant differences in survival and settlement between larvae fed with Nannochloropsis sp. and other diets. All diet treatments yielded similar juvenile sea cucumber output. In the second trial, A. japonicus larvae were fed equally four times daily at three different rations (5000, 20 000 and 40 000 cells mL−1 day−1). Larvae fed 20 000 cells mL−1 day−1 were significantly larger than larvae in other groups and experienced the highest survival rate. In the third trial, A. japonicus larvae were fed 20 000 cells mL−1 day−1 in three different frequency (2, 3 and 4 meals day−1). The greatest body length was observed in larvae that received 3 meals day−1. Survival and settlement of larvae fed 2 meals day−1 were significantly lower than other two groups. These results suggest that Nannochloropsis sp. can be used as a diet for the large-scale production of A. japonicus seed, and larvae fed three times daily at a ration of 20 000 cell mL−1 day−1 are recommended for hatchery production of A. japonicus. [ABSTRACT FROM AUTHOR]

Physico-stimulant like audible sound is one of the new promising methods for enhancing microalgae growth rate. Here, microalgae Haematococcus pluvialis was cultivated with the addition of audible sound with titles “Blues for Elle” and “Far and Wide.” The objective of this research was to evaluate the effect of audible sound to the growth and productivity of microalgae. The experiment has been conducted by exposing the audible sound for 8 h in 22 days to microalgae cultivation. The result showed that microalgae H. pluvialis treated by the music “Blues for Elle” shows the highest growth rate (0.03 per day), and 58% higher than the one without audible sound. The average number of cells in stationary phase is 0.76 × 10 4 cells/mL culture and the productivity is 3.467 × 10 2 cells/mL/day. The pH of microalgae medium slightly decreases because of proton production during photosynthesis process. The kinetic rate constant (k app ) is 0.078 per day, reaction half-life (t 1/2 ) is 8.89 days, and catalytic surface (K surf ) is 1.66 × 10 − 5 /day/cm 2 . In conclusion, this audible sound is very useful to stimulate microalgae growth rate, especially H. pluvialis . [ABSTRACT FROM AUTHOR]

In human financial and social systems, exchanges of information among individuals cause speculative bubbles, behavioral cascades, and other correlated actions that profoundly influence system-level function. Exchanges of information are also widespread in ecological systems, but their effects on ecosystem-level processes are largely unknown. Herbivory is a critical ecological process in coral reefs, where diverse assemblages of fish maintain reef health by controlling the abundance of algae. Here, we show that social interactions have a major effect on fish grazing rates in a reef ecosystem. We combined a system for observing and manipulating large foraging areas in a coral reef with a class of dynamical decision-making models to reveal that reef fish use information about the density and actions of nearby fish to decide when to feed on algae and when to flee foraging areas. This "behavioral coupling" causes bursts of feeding activity that account for up to 68% of the fish community's consumption of algae. Moreover, correlations in fish behavior induce a feedback, whereby each fish spends less time feeding when fewer fish are present, suggesting that reducing fish stocks may not only reduce total algal consumption but could decrease the amount of algae each remaining fish consumes. Our results demonstrate that social interactions among consumers can have a dominant effect on the flux of energy and materials through ecosystems, and our methodology paves the way for rigorous in situ measurements of the behavioral rules that underlie ecological rates in other natural systems. [ABSTRACT FROM AUTHOR]

Zooplankton frequently face dietary limitation caused by imbalances between their nutrient requirements and the nutrient content of their phytoplankton food. While insufficient nutrition is acknowledged to affect growth and reproduction of zooplankton, the effect of dietary limitation on other aspects of their metabolism remains poorly studied. One understudied biochemical response associated with nutrient stress is changes to the free amino acid (FAA) composition of body tissues resulting from changes in dietary supply. We examined changes in FAA composition in two cladoceran species ( Daphnia magna and Daphnia pulex) in response to stress created by ecologically relevant food conditions: low food quantities, high algal carbon: nitrogen (C:N) ratios, and high algal C: phosphorus (P) ratios. We measured 14 FAA after extracting them from lyophilized whole Daphnia grown under these contrasting algal diets. Generally, low food quantity and low algal P increased body FAA content in both daphnid species while many essential FAA decreased due to N-limitation. While significant responses to diet were seen for each daphnid species, the nature of these responses depended on the type of nutritional stress, the FAA examined, and on the species. Non-parametric discriminant analysis exhibited a high predictive ability to classify unknown zooplankton into the correct diet category. The observed changes in body FAA profiles of Daphnia illustrate strong effects that algal food quality can have on the biochemistry of planktonic consumers. Furthermore these results demonstrate body FAA composition of zooplankton may provide an important source of information about zooplankton nutrient limitation especially combined with other nutrient-dependent molecular responses. [ABSTRACT FROM AUTHOR]

Algae are higher-quality food resources than allochthonous plant litter for stream invertebrates, in part, because of their higher content of polyunsaturated fatty acids (PUFAs). We tested the hypothesis that algal biofilms on the surfaces of leaf litter improve the nutritional quality of terrestrial inputs for invertebrate shredders. We used a laboratory feeding experiment with 2 light levels (open and shaded) and 2 nutrient regimes (ambient and enriched) to manipulate the algal biofilms that form on leaf surfaces (Lophostemon confertus). We assessed how these treatments affected the fatty acid (FA) composition of these biofilms and the somatic growth of a stream invertebrate shredder (Anisocentropus bicoloratus, Trichoptera) that feeds on the conditioned leaf litter. Shredders reached a significantly larger size when nutrients were added, and leaf mass loss was significantly greater in these treatments than in treatments without nutrients. Shredder growth was affected significantly by leaf PUFA content, and variations in shredder PUFA content were consistent with those in leaf PUFAs. Our results suggest that high-quality algae attached to leaf litter regulated the PUFA composition and improved the somatic growth of these shredders. Our data provide evidence that the availability of high-quality algae enhances dietary use of low-quality riparian leaf litter in stream food webs. [ABSTRACT FROM AUTHOR]

Recent investigators have emphasized that food quality has greater importance than food quantity for herbivore somatic growth. Herbivore growth is thought to be regulated by light and nutrients through changes in food elemental ratios, but our knowledge of the mechanisms driving grazer growth in stream ecosystems is scarce. We manipulated light (through shading) and nutrients (fertilizer addition) in 3 headwater streams in southeastern Queensland, Australia, and measured the responses of natural grazer communities. The growth responses of Austrophlebioides and Helicopsyche to light and nutrients differed with their body size and periphyton food quality. Large larvae were more sensitive to increased light and nutrient availability than were small larvae. Light induced a significant negative effect on Austrophlebioides growth, and this impact increased with increasing nutrient addition. Nutrients had a pronounced positive effect on Helicopsyche growth regardless of light intensity. These responses reflected changes in food quality. Periphyton food quality in terms of C:N played a more decisive role in grazer growth than algal food quantity (as chlorophyll a). The growth of large larvae was significantly greater under low light intensity and nutrient-enriched conditions where high-quality food was more abundant than under high-light and low-nutrient conditions where periphyton food quality was low. Our results suggest that changes in riparian vegetation or nutrient inputs can significantly influence grazer growth through changes in periphyton C: N. We recommend that future investigators of foodweb responses to riparian canopy change or nutrient enrichment on stream ecosystems pay more attention to the effects of algal food quality rather than quantity. [ABSTRACT FROM AUTHOR]

The element content of sixty seven food supplements falling into five different categories was determined with an Agilent 8800 Triple Quadrupole ICP-MS and the maximum daily intake calculated. The determined elements were: Rb, Cs, Mg, Ca, Sr, Ba, V, Cr, Mn, Fe Co, Cu, Zn, Mo, Se, I, Br, B, Al, As, Cd, Sb and Pb. The majority of supplements contained significantly less essential elements than the recommended daily intake. Exceptions were two algae based products leading to a very high iron intake. The use of 3 other algae based products would result in increased iodine intake. Of the non-essential elements determined the intake of inorganic arsenic from all supplements was below the limit set by ANSI 173, but several algae based and one garlic based supplement contained levels of inorganic arsenic above the limit set in China for food supplements. Generally garlic, fish oil and krill oil based products pose little risk of inadvertent increased intake of essential and non-essential elements. Algae based products can lead to intakes above the recommended limits for specific elements and generally contain higher amounts of all elements. None of the tested food supplements poses a direct risk to healthy adults. [ABSTRACT FROM AUTHOR]

Algae-based fuels are considered to be the most sustainable, renewable, effective and environment friendly response to climate change and food–feed security, as well as the only renewable energy resource that has the capacity to meet the global demand for fuels in the long-term. Therefore, an extended overview of the composition, properties and challenges of algae biomass for biofuel application was conducted based on reference peer-reviewed data plus own investigations. Initially, some general considerations such as current bioenergy situation and significance of biofuel generations, as well as different aspects related to biomass use as biofuels are discussed. Then, common issues concerning taxonomical classification, habitat environment, carbon reserve capacity, production, use, and main advantages and disadvantages of algae or algae biofuel are addressed. Further, more than 135 characteristics related to the chemical, phase and mineral composition and properties of algae and algae ash are evaluated and compared to those of terrestrial biomass, coal and their ashes. As a result specific benefits and obstacles connected with the composition and properties of algae and algae ash are discussed. The behaviour of organic and inorganic matter during algae combustion is also described. Finally, the major technological and environmental challenges related to algae-based fuels are emphasized. The present data demonstrate that the high contents of inorganic matter with unfavourable modes of element occurrences (chlorides, sulphates, carbonates, oxalates, nitrates and some oxyhydroxides, phosphates and amorphous material) in algae and algae ash provoke the most critical technological and environmental challenges during algae processing for biofuel application and especially during algae thermochemical conversion. Another very important challenge addressed is the indefinite availability of sustainable algae resources for production of biofuels and biochemicals and certain recommendations are given. It was found that the disadvantages of algae biofuel application prevail significantly over the advantages; however, the major economic, environmental and social benefits appear to compensate the technological and other barriers caused by the unfavourable composition and properties of algae. [ABSTRACT FROM AUTHOR]

While many streams and rivers are dominated by terrestrial inputs of organic carbon, algae are an important trophic base for stream food webs. However, the nutritional importance of algae for stream invertebrates only recently has been highlighted. Algae are acknowledged as higher quality food than terrestrial organic matter for the growth and reproduction of invertebrates. In part, this is because of higher algal polyunsaturated fatty-acid ( PUFA) content. Here, we review the important influence of algal food quality, as assessed by PUFA, in stream food webs., Current field investigations have mainly focused on the fatty-acid dynamics of macroinvertebrates, and indicate that algal eicosapentaenoic acid ( EPA), α-linolenic acid ( ALA) and linoleic acids ( LIN) are present in all macroinvertebrates. However, fungal and bacterial tracers have also been observed in a range of macroinvertebrates. The omega-3 (ω3)/omega-6 (ω6) ratio >1 in most macroinvertebrates strongly indicates that dietary energy of algae is highly retained in stream food webs. Interspecific differences in PUFA composition seem to be affected by dietary PUFA and consumer physiology., Some studies have suggested that besides dietary EPA, the shorter chain C18 PUFA LIN and ALA also can improve growth and reproduction of stream invertebrate consumers. Some macroinvertebrates may preferentially retain or synthesise long-chain PUFA from C18 PUFA when experiencing low-quality food. However, this process is controversial since other species have shown very limited ability to synthesise long-chain PUFA., Algal PUFA composition is strongly influenced by abiotic factors, particularly light, nutrients, and temperature. Human disturbance (i.e. riparian vegetation removal and nutrient inputs) on algal PUFA content and their consequent effects on macroinvertebrates and fish clearly warrant further scientific attention. Controlled feeding trials and manipulative studies are required to measure PUFA conversion capacities and reproductive investment of stream macroinvertebrates under different food quality conditions, which will provide insights into how freshwater species can cope with different nutritional food conditions due to human disturbance and climate change. [ABSTRACT FROM AUTHOR]

Herbivore distribution can impact community structure and ecosystem function. On coral reefs, herbivores are thought to play an important role in promoting coral dominance, but how they are distributed relative to algae is not well known. Here, we evaluated whether the distribution, behavior, and condition of herbivorous fishes correlated with algal resource availability at six sites in the back reef environment of Moorea, French Polynesia. Specifically, we tested the hypotheses that increased algal turf availability would coincide with (1) increased biomass, (2) altered foraging behavior, and (3) increased energy reserves of herbivorous fishes. Fish biomass and algal cover were visually estimated along underwater transects; behavior of herbivorous fishes was quantified by observations of focal individuals; fish were collected to assess their condition; and algal turf production rates were measured on standardized tiles. The best predictor of herbivorous fish biomass was algal turf production, with fish biomass increasing with algal production. Biomass of herbivorous fishes was also negatively related to sea urchin density, suggesting competition for limited resources. Regression models including both algal turf production and urchin density explained 94 % of the variation in herbivorous fish biomass among sites spread over ~20 km. Behavioral observations of the parrotfish Chlorurus sordidus revealed that foraging area increased as algal turf cover decreased. Additionally, energy reserves increased with algal turf production, but declined with herbivorous fish density, implying that algal turf is a limited resource for this species. Our findings support the hypothesis that herbivorous fishes can spatially track algal resources on coral reefs. [ABSTRACT FROM AUTHOR]

The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long-chain poly unsaturated fatty acids ( PUFAs), we hypothesized that the diatom-consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga ( Chlorella vulgaris) and a diatom ( Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long-chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem. [ABSTRACT FROM AUTHOR]

Micromoina arboricola , one of the smallest moinids on record, is currently known from a single tree hole in a tropical forest, containing a small volume of humic water, in quasi absolute darkness. We test whether it has been refuted to this environment by superior competitors, or whether it is genuinely adapted to this life space by culturing it in its native environment, and in a clear water environment supplemented with algal food, yeast and fermented fish ration. Only maturation time is similar between both treatments. Total offspring, number of clutches, average clutch size and longevity are higher in the humic treatment. Population growth is initially higher in the clearwater treatment, but then collapses. In the humic treatment there is a steady ascent towards a stable plateau. We conclude that the species is better adapted to its microcosm than to a ‘normal’ aquatic biotope. [ABSTRACT FROM AUTHOR]

The amount of energy lowing to top trophic levels depends on primary production and the efficiency at which it is converted to production at each trophic level. In aquatic systems, algal production is often limited by light and nutrients, and the nutritional quality of algae depends on the relative balance of these two resources. In this study, we used a mesocosm experiment to examine how light and nutrient variation affected food chain efficiency (FCE, defined as the proportion of primary production converted to top trophic level production), using a food web with benthic and pelagic food chains. We also related variation in benthic and pelagic efficiencies to the nutritional quality of primary producers, i.e. carbon:nitrogen:phosphorus stoichiometry. As predicted, pelagic and benthic FCEs were highest under low light/high nutrient conditions, the treatment with the best algal food quality, i.e. the lowest C:nutrient ratios. Pelagic FCE and pelagic herbivore efficiency (HEP) were more responsive than benthic FCE to variation in light and nutrients. Furthermore, pelagic FCE and HEP were highly correlated with algal C:P, suggesting 'carryover effects' of algal food quality on carnivores (larval fish) via effects on herbivore (zooplankton) quality. Benthic (tadpole) production was primarily explained by primary production rate, suggesting food quantity rather than quality drives their production. However, benthic FCE was also highest at low light/high nutrients and was significantly correlated with food quality. The stronger effect of food quality in mediating pelagic compared to benthic efficiencies, is consistent with differences in the stoichiometric mismatches between algae and consumers. Pelagic FCE and HEP were more likely to be P-limited, whereas benthic FCE was more likely N-limited. This study is the first to examine both pelagic and benthic FCE within the same system, and highlights the importance of differential consumer needs in determining how food quality affects energy transfer efficiency. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation is known to be highly variable in aquatic ecosystems. It has been suggested that UV-exposed organisms may demonstrate enough phenotypic plasticity to maintain the relative fitness of natural populations. Our long-term objective is to determine the potential photoprotective effect of vitamin D3 on Daphnia pulex exposed to acute or chronic UV radiation. Herein we report our initial findings in this endeavor. D. pulex survival and reproduction (fitness) was monitored for 5 d as a proof of concept study. Significantly higher fitness was observed in the D. pulex with D3 than those without (most extreme effects observed were 0% survival in the absence of D3 and 100% with 10 ppm D3). Vitamin D3 was isolated from the culture media, the algal food (Pseudokirchneriella), and the D. pulex and quantified using high performance liquid chromatography (HPLC). Vitamin D3 was fluorescently labeled using a phenothiazinium dye and added to cultures of D. pulex. Images demonstrating the uptake of D3 into the tissues and carapace of the D. pulex were acquired. Our initial findings suggest a positive role for D3 in ecosystems as both UV-stressed algae and Daphnia sequester D3, and D. pulex demonstrate increased fitness in the presence of D3. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation is known to be highly variable in aquatic ecosystems. It has been suggested that UV-exposed organisms may demonstrate enough phenotypic plasticity to maintain the relative fitness of natural populations. Our long-term objective is to determine the potential photoprotective effect of vitamin D3 on Daphnia pulex exposed to acute or chronic UV radiation. Herein we report our initial findings in this endeavor. D. pulex survival and reproduction (fitness) was monitored for 5 d as a proof of concept study. Significantly higher fitness was observed in the D. pulex with D3 than those without (most extreme effects observed were 0% survival in the absence of D3 and 100% with 10 ppm D3). Vitamin D3 was isolated from the culture media, the algal food (Pseudokirchneriella), and the D. pulex and quantified using high performance liquid chromatography (HPLC). Vitamin D3 was fluorescently labeled using a phenothiazinium dye and added to cultures of D. pulex. Images demonstrating the uptake of D3 into the tissues and carapace of the D. pulex were acquired. Our initial findings suggest a positive role for D3 in ecosystems as both UV-stressed algae and Daphnia sequester D3, and D. pulex demonstrate increased fitness in the presence of D3. [ABSTRACT FROM AUTHOR]

Environmental stress can influence species traits and performance considerably. Using a seaweed-snail system from NW (Nova Scotia) and NE (Helgoland) Atlantic rocky shores, we examined how physical stress (wave exposure) modulates traits in the seaweed Fucus vesiculosus and indirectly in its main consumer, the periwinkle Littorina obtusata., In both regions, algal tissue toughness increased with wave exposure. Reciprocal-transplant experiments showed that tissue toughness adjusted plastically to the prevailing level of wave exposure., Choice experiments tested the feeding preference of snails from sheltered, exposed and very exposed habitats for algae from such wave exposures. Snails from exposed and very exposed habitats consumed algal tissues at similar rates irrespective of the exposure of origin of the algae. However, snails from sheltered habitats consumed less algal tissues from very exposed habitats than tissues from sheltered and exposed habitats. Choice assays using reconstituted algal food (triturated during preparation) identified high thallus toughness as the explanation for the low preference of snails from sheltered habitats for algae from very exposed habitats., Ultrastructural analyses of radulae indicated that rachidian teeth were longest and the number of cusps in lateral teeth (grazing-relevant traits) was highest in snails from very exposed habitats, suggesting that radulae are best suited to rupture tough algal tissues in such snails., No-choice feeding experiments revealed that these radular traits were also phenotypically plastic, as they adjusted to the toughness of the algal food., Synthesis. This study indicates that the observed plasticity in the feeding ability of snails is mediated by wave exposure through phenotypic plasticity in the tissue toughness of algae. Thus, plasticity in consumers and their resource species may reduce the potential effects of physical stress on their interaction. [ABSTRACT FROM AUTHOR]

We examined the potential for a trait-mediated indirect interaction (TMII), whereby a behavioural response to a predator (crab Cancer borealis ) alters the per capita effect of a reacting species (sea urchin Strongylocentrotus droebachiensis ) on its algal food (kelp Saccharina latissima ), in field and laboratory experiments. We used time-lapse video to monitor sea urchin movement in response to either an attractant food cue (kelp) or a repellant predation-risk cue (crabs) placed in small cages at the centre of 7 m 2 circular plots in a wave-exposed sea urchin barrens off Nova Scotia. We found that sea urchins generally moved randomly over the rock substratum and showed a limited response to cues emanating from a cage with kelp, with a few individuals exhibiting directed movement towards kelp and greater proportion of urchins in contact with the cue cage (with kelp) compared to the control (without kelp) at the end of the experiment. Similarly, only a few individuals that came in close contact with a cage containing crabs showed a clear flight response, compared to the control. In experiments with individual kelp thalli that were systematically dispersed around the central cage in the same plots, we found that the presence of crabs in the cage did not reduce sea urchin grazing rates on kelp compared to a control without crabs. We observed similar results using a similar experimental design in large tanks (900 L) under controlled flow conditions in the laboratory. We conclude that C. borealis does not significantly inhibit the foraging activity of S. droebachiensis under turbulent flow conditions in nature, and that a TMII is unlikely to contribute to a trophic cascade in the shallow rocky subtidal zone of the Northwest Atlantic. [ABSTRACT FROM AUTHOR]

The study objective was to investigate total phenolic content using Folin-Ciocalteu’s method, to assess nine phenols by HPLC, to determine antioxidant capacity of the water soluble compounds (ACW) by a photochemiluminescence method, and to calculate the correlation coefficients in commercial algal food products from brown (Laminaria japonica, Eisenia bicyclis, Hizikia fusiformis, Undaria pinnatifida) and red (Porphyra tenera, Palmaria palmata) seaweed, green freshwater algae (Chlorella pyrenoidosa), and cyanobacteria (Spirulina platensis). HPLC analysis showed that the most abundant phenolic compound was epicatechin. From spectrophotometry and ACW determination it was evident that brown seaweed Eisenia bicyclis was the sample with the highest phenolic and ACW values (193 mg·g−1 GAE; 7.53 μmol AA·g−1, respectively). A linear relationship existed between ACW and phenolic contents (r = 0.99). Some algal products seem to be promising functional foods rich in polyphenols. [ABSTRACT FROM AUTHOR]

Fucus spiralis, Porphyra sp. and Osmundea pinnatifida are macroalgae consumed as food in some of the Azorean Islands, but little information is available on their nutritional value. This paper presents information on the nutritional aspects in terms of proteins (9.71-24.82%), lipids (5.23-8.88%), soluble carbohydrates (17.59-25.37%), ash (22.31-38.55%), minerals (0.96-1.82 for Na/K ratios) and fat soluble vitamins A (1.20-1.41%) and E (4.86-51.14%) contents on dry weight basis. Fatty acid (SFA, MUFA, PUFA and n6/n3 and h/H ratios) and amino acid profiles, and antioxidant properties were also reported. All the three species contained measurable quantities of 9 of 10 essential amino acids (41.62-63.50% of the total amino acids). The regular consumption of these algae allied with the low level of seawater pollution around Azores Islands will improve human health conditions and will have a protective effect on the most common degenerative diseases. [ABSTRACT FROM AUTHOR]

BACKGROUND The objectives of this study were to examine protein and amino acid composition, lipid and fatty acid composition, along with a range of essential minerals in common Norwegian seaweed species representing the red ( Palmaria palmata and Vertebrata lanosa), green ( Cladophora rupestris, Enteromorpha intestinalis and Ulva lactuca) and brown ( Alaria esculenta, Laminaria digitata, Laminaria hyperborea, Fucus vesiculosus and Pelvetia canaliculata) classes and assess their potential as alternatives to cereals in food and feed. As macroalgae accumulate heavy metals, arsenic, cadmium and mercury were also analyzed. RESULTS Proteins ranged from 34 to 123 g kg−1 dry weight ( DW) and the essential amino acid levels may cover both human and salmonid requirements. Lipids were low (6-58 g kg−1 DW), but the red algae had high relative content of long-chained omega-3 fatty acids (32-34 % of the fatty acids). Iodine contents were particularly high in the Laminaria species. Of the heavy metals only arsenic levels may be of concern. CONCLUSION In total, the red alga P. palmata was regarded as the best alternative to cereals in food and feed. For several of the other species, single-component extraction for the ingredients market may be better than using the whole product. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Studying non-model organisms is crucial in the context of the current development of genomics and transcriptomics for both physiological experimentation and environmental characterization. We investigated the transcriptomes of two marine planktonic ciliates, the mixotrophic oligotrich Strombidium rassoulzadegani and the heterotrophic choreotrich Strombidinopsis sp., and their respective algal food using Illumina RNAseq. Our aim was to characterize the transcriptomes of these contrasting ciliates and to identify genes potentially involved in mixotrophy. We detected approximately 10,000 and 7,600 amino acid sequences for S. rassoulzadegani and Strombidinopsis sp., respectively. About half of these transcripts had significant BLASTP hits (E-value <10−6) against previously-characterized sequences, mostly from the model ciliate Oxytricha trifallax. Transcriptomes from both the mixotroph and the heterotroph species provided similar annotations for GO terms and KEGG pathways. Most of the identified genes were related to housekeeping activity and pathways such as the metabolism of carbohydrates, lipids, amino acids, nucleotides, and vitamins. Although S. rassoulzadegani can keep and use chloroplasts from its prey, we did not find genes clearly linked to chloroplast maintenance and functioning in the transcriptome of this ciliate. While chloroplasts are known sources of reactive oxygen species (ROS), we found the same complement of antioxidant pathways in both ciliates, except for one enzyme possibly linked to ascorbic acid recycling found exclusively in the mixotroph. Contrary to our expectations, we did not find qualitative differences in genes potentially related to mixotrophy. However, these transcriptomes will help to establish a basis for the evaluation of differential gene expression in oligotrichs and choreotrichs and experimental investigation of the costs and benefits of mixotrophy. [ABSTRACT FROM AUTHOR]

The combined effects of initial stocking density (2, 5, 10 individuals [inds]/mL) and feed ration (5×103, 20×103, 40×103, 100×103cells·ind−1·d−1) on growth, survival, and ingestion rate of larval geoduck clamsPanopea generosafedIsochrysissp. (Tahitian strain, TISO clone) were assessed. All three measurements were significantly affected by stocking density, ration, and their interaction. Growth rate ranged from 2.15 to 3.85 μm/d in the various treatments. It increased with stocking density at 5×103cells·ind−1·d−1, was significantly higher at 5 than at 2 inds/mL at 20×103cells·ind−1·d−1, and was significantly higher at 2 and 5 than at 10 inds/mL at 40×103and 100×103cells·ind−1·d−1. Growth rate increased with increasing ration up to 40×103cells·ind−1·d−1at 2 and 5 inds/mL, but decreased with increasing ration at 10 inds/mL. Percent survival over the experiment duration (23 d) ranged from 7% to 56% in the various treatments and generally decreased with increasing stocking density. There was no significant effect of ration on percent survival at 2 and 5 inds/mL, but survival decreased with increasing ration at 10 inds/mL. Ingestion rate ranged from 2×103to 29×103cells·ind−1·d−1in the various treatments. It was not significantly affected by stocking density at 5×103and 20×103cells·ind−1·d−1, but larvae held at 2 and 5 inds/mL had significantly higher ingestion rates than those stocked at 10 inds/mL at 40×103and 100×103cells·ind−1·d−1. Ingestion rate increased with ration at 2 and 5 inds/mL but was not significantly affected by ration at 10 inds/mL. Due to the significant interaction of the treatment factors, stocking density-specific ration levels must be selected in order to maximize growth and survival. Received July 8, 2013; accepted December 22, 2013 [ABSTRACT FROM PUBLISHER]

The identity of food sources and feeding preferences of specialist herbivores have been commonly inferred from spatial associations between consumer and food items. However, such basic information for well-known marine herbivores, sacoglossans (sea slugs), and their algal diets remains disappointingly lacking, especially from field studies. The sacoglossan, Elysia clarki (Pierce et al. in Molluscan Res 26:23-38, ), is kleptoplastic and sequesters chloroplasts from algal food to photosynthesize, so DNA identification of sequestered chloroplasts was employed to verify the algal species fed upon by the slug across its geographic range. The molecular information on the algae consumed by E. clarki was combined with field surveys of slugs and algae in slug habitats in the Florida Keys in July and August of 2008 in order to evaluate whether the diet of this herbivore could be predicted based on its spatial association with algae in the field. A considerable mismatch between food availability and kleptoplast identity was recorded. E. clarki commonly occupied areas devoid of potential food and often contained symbiotic plastids from algal species different from those most frequently found in the surveyed habitats. In three of the four study sites, algal species present were poor predictors of slug diet. These findings suggest that the photosynthetic capability of E. clarki may release the slug from the constraint of requiring proximity to its food sources and may allow for the potential lack of spatial coupling between this herbivore and its algal food. This combination of field surveys and DNA barcoding provided critical and previously unavailable information on herbivore feeding in this marine system. [ABSTRACT FROM AUTHOR]