Michael Roleda
Research Scientist
(+47) 405 57 498
michael.roleda@nibio.no
Place
Bodø
Visiting address
Torggården, Kudalsveien 6, NO-8027 Bodø
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
The large brown seaweeds (kelps) are potential sources of protein for animal feed. They have lower protein contents than most red and green algae, but due to potential for large-scale production, they may represent a significant future protein source. The impact of pH, temperature and polysaccharide-degrading enzymes on the solubility and extraction yields of protein from wet Saccharina latissima biomass was investigated. The protein solubility increased with increasing pH and reached maximum of 23% at pH 11, determined as total amino acids (TAA). The enzyme treatments increased the release of soluble compounds by 30–35%. The highest protein yield obtained was 19%, using a ratio of water to wet seaweed of 1:1 for extraction. Even if the yields can be increased by increasing the water amounts used for extraction, the majority of the protein would remain in the insoluble residue after separation. The strategy for production of a larger quantity of protein-enriched biomass was therefore to maintain the insoluble fraction as the product. A pilot scale production was carried out, also including the red algae Palmaria palmata. In total 750 kg S. latissima and 195 kg P. palmata were processed. The protein content in the product increased from 10 to 20% of dry weight (dw) for S. latissima and from 12 to 28% for P. palmata, with yields of 79 and 69%, respectively. The ash content was reduced from 44 to 26% and from 12 to 5% of dw, respectively, for the two species. The main protein loss was free amino acids, which constituted approximately 10% of TAA in the feedstocks. Less essential than non-essential amino acids were lost, thus, the essential amino acids were enriched in the product.
Abstract
Kelp forests in the North Atlantic are at risk of decline at their warm temperature distribution margins due to anthropogenic temperature rise and more frequent marine heat waves. To investigate the thermal adaptation of the cold-temperate kelp Laminaria digitata, we sampled six populations, from the Arctic to Brittany (Spitsbergen, Tromsø, Bodø [all Norway], Helgoland [Germany], Roscoff and Quiberon [both France]), across the species’ entire distribution range, spanning 31.5° latitude and 12-13°C difference in mean summer sea surface temperature. We used pooled vegetative gametophytes derived from several sporophytes to approximate the genetic diversity of each location. Gametophytes were exposed to (sub-) lethal high (20-25°C) and (sub-) optimal low (0-15°C) temperature gradients in two full-factorial, common-garden experiments, subjecting subsets of populations from different origins to the same conditions. We assessed survival of gametophytes, their ability to develop microscopic sporophytes, and subsequent growth. We hypothesized that the thermal performance of gametophytes and microscopic sporophytes corresponds to their local long-term thermal history. Integrated gametophyte survival revealed a uniform upper survival temperature (UST) of 24°C among five tested populations (Tromsø to Quiberon). In contrast, following two weeks of thermal priming of gametophytes at 20-22°C, sporophyte formation at 15°C was significantly higher in southern populations (Quiberon and Roscoff) compared to the high-latitude population of Tromsø. Between 0-15°C, survival of the Arctic population (Spitsbergen) was negatively correlated with increasing temperatures, while the southern-most population (Quiberon) showed the opposite. Thus, responses of survival at low, and sporophyte formation at high temperatures, support the concept of local adaption. On the other hand, sporophyte formation between 0-15°C peaked at 6-9°C in the Quiberon and at 9-12°C in the Spitsbergen population. Sporophyte growth rates (GR) both in length and width were similar for Spitsbergen, Tromsø and Quiberon; all had maximum GRs at 12-15°C and low GRs at 0-6°C. Therefore, responses of sporophyte formation and growth at low temperatures do not reflect ecotypic adaptation. We conclude that L. digitata populations display trait-dependent adaptation, partly corresponding to their local temperature histories and partly manifesting uniform or unpredictable responses. This suggests differential selection pressures on the ontogenetic development of kelps such as L. digitata.
Abstract
Seaweeds are increasingly used in European cuisine. Until the recent use of molecular techniques, species identification was solely based on morphology which cannot easily discriminate morphologically simple but phenotypically plastic taxa such as the green algal genus Ulva. For example, current taxonomic protocol effectively reassigned the previously known European ʻUlva lactuca L.’ under the name Ulva fenestrata Postels & Ruprecht. Also, the presumptive Ulva lactuca approved by the Institute for Reference Materials and Measurements (IRMM, Joint Research Center, European Commission) as Certified Reference Material (CRM) for analytical quality assurance was genetically identified as U. rigida C.Agardh. It is very likely that different Ulva species under various names have been consumed as food not only in Europe, but also worldwide. In this regard, when chemical composition and nutritional quality of different seaweed species meet a set of food standard criteria, and food safety hazards are mitigated, they should be endorsed for consumption. In the case of Ulva, we propose that different bladed and tubular species should generally be accepted for food consumption in Europe.
Authors
Michael Roleda Sandra Lage Daniel Fonn Aluwini Celine Rebours May Bente Brurberg Udo Nitschke Francesco G. GentiliAbstract
No abstract has been registered
Abstract
Macrocystis pyrifera is a major habitat forming kelp in coastal ecosystems of temperate regions of the northern and southern hemispheres. We investigated the seasonal occurrence of adult sporophytes, morphological characteristics, and reproductive phenology at two sites within a wave-protected harbour and two wave-exposed sites in southern New Zealand every 3–4 months between 2012 and 2013. Seasonality in reproduction was assessed via the number of sporophylls, the occurrence of sori on sporophylls, and non-sporophyllous laminae (fertile pneumatocyst-bearing blades and fertile apical scimitars), meiospore release, and germination. We found that M. pyrifera was present and reproductive year-round in three of the four sites, and patterns were similar for the wave-exposure conditions. Sori were found on pneumatocyst-bearing blades and apical scimitars in addition to the sporophylls, and viable meiospores were released from all three types of laminae. Morphological variations between sites with different wave exposure indicate that sporophytes from wave-protected sites have bigger blades and holdfasts and are longer than those from wave-exposed sites. We discuss the implications of these biological variables for the ecology of M. pyrifera inhabiting different wave exposure environments in southern New Zealand.
Abstract
Kelps are important foundation species in coastal ecosystems currently experiencing pronounced shifts in their distribution patterns caused by ocean warming. While some populations found at species’ warm distribution edges have been recently observed to decline, expansions of some species have been recorded at their cold distribution edges. Reduced population resilience can contribute to kelp habitat loss, hence, understanding intraspecific variations in physiological responses across a species’ latitudinal distribution is crucial for its conservation. To investigate potential local responses of the broadly distributed kelp Saccharina latissima to marine heatwaves in summer, we collected sporophytes from five locations in Europe (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer), including populations exposed to the coldest and warmest local temperature regimes. Meristematic tissue from sporophytes was subjected to increasing temperatures of 1+2, 1+4 and 1+6 ◦C above the respective mean summer temperatures (control, 1±0 ◦C) characteristic for each site. Survival and corresponding physiological and biochemical traits were analyzed. Vitality (optimum quantum yield, Fv/Fm) and growth were monitored over time and biochemical responses were measured at the end of the experiment. Growth was highest in northern and lowest in southern populations. Overall, northern populations from Spitsbergen, Bodø and Bergen were largely unaffected by increasing summer temperatures up to 1+6 ◦C. Conversely, sporophytes from Helgoland and Locmariaquer were markedly stressed at 1+6 ◦C: occurrence of tissue necrosis, reduced Fv/Fm, and a significantly elevated de-epoxidation state of the xanthophyll cycle (DPS). The variations in phlorotannins, mannitol and tissue C and N contents were independent of temperature treatments and latitudinal distribution pattern. Pronounced site-specific variability in response to increasing temperatures implies that exceeding a threshold above the mean summer temperature exclusively affect rear-edge (southernmost) populations.
Authors
Michael Roleda Sandra Lage Daniel Fonn Aluwini Celine Rebours May Bente Brurberg Udo Nitschke Francesco G. GentiliAbstract
The increasing use of seaweeds in European cuisine led to cultivation initiatives funded by the European Union. lactuca, commonly known as sea lettuce, is a fast growing seaweed in the North Atlantic that chefs are bringing into the local cuisine. Here, different strains of Arctic U. lactuca were mass-cultivated under controlled conditions for up to 10 months. We quantified various chemical constituents associated with both health benefits (carbohydrates, protein, fatty acids, minerals) and health risks (heavy metals). Chemical analyses showed that long-term cultivation provided biomass of consistently high food quality and nutritional value. Concentrations of macroelements (C, N, P, Ca, Na, K, Mg) and micronutrients (Fe, Zn, Co, Mn, I) were sufficient to contribute to daily dietary mineral intake. Heavy metals (As, Cd, Hg and Pb) were found at low levels to pose health risk. The nutritional value of Ulva in terms of carbohydrates, protein and fatty acids is comparable to some selected fruits, vegetables, nuts and grains.
Authors
Daniel Liesner Louise Fouqueau Myriam Valero Michael Roleda Gareth A. Pearson Kai Bischof Klaus Valentin Inka BartschAbstract
To understand the thermal plasticity of a coastal foundation species across its latitudinal distribution, we assess physiological responses to high temperature stress in the kelp Laminaria digitata in combination with population genetic characteristics and relate heat resilience to genetic features and phylogeography. We hypothesize that populations from Arctic and cold-temperate locations are less heat resilient than populations from warm distributional edges. Using meristems of natural L. digitata populations from six locations ranging between Kongsfjorden, Spitsbergen (79°N), and Quiberon, France (47°N), we performed a common-garden heat stress experiment applying 15°C to 23°C over eight days. We assessed growth, photosynthetic quantum yield, carbon and nitrogen storage, and xanthophyll pigment contents as response traits. Population connectivity and genetic diversity were analyzed with microsatellite markers. Results from the heat stress experiment suggest that the upper temperature limit of L. digitata is nearly identical across its distribution range, but subtle differences in growth and stress responses were revealed for three populations from the species’ ecological range margins. Two populations at the species’ warm distribution limit showed higher temperature tolerance compared to other populations in growth at 19°C and recovery from 21°C (Quiberon, France), and photosynthetic quantum yield and xanthophyll pigment responses at 23°C (Helgoland, Germany). In L. digitata from the northernmost population (Spitsbergen, Norway), quantum yield indicated the highest heat sensitivity. Microsatellite genotyping revealed all sampled populations to be genetically distinct, with a strong hierarchical structure between southern and northern clades. Genetic diversity was lowest in the isolated population of the North Sea island of Helgoland and highest in Roscoff in the English Channel. All together, these results support the hypothesis of moderate local differentiation across L. digitata's European distribution, whereas effects are likely too weak to ameliorate the species’ capacity to withstand ocean warming and marine heatwaves at the southern range edge.
Abstract
Pythium species are ubiquitous organisms known to be pathogens to terrestrial plants and marine algae. While several Pythium species (hereafter, Pythium) are described as pathogens to marine red algae, little is known about the pathogenicity of Pythium on marine green algae. A strain of a Pythium was isolated from a taxonomically unresolved filamentous Ulva collected in an intertidal area of Oslo fjord. Its pathogenicity to a euryhaline Ulva intestinalis collected in the same area was subsequently tested under salinities of 0, 15, and 30 parts per thousand (ppt). The Pythium isolate readily infected U. intestinalis and decimated the filaments at 0 ppt. Mycelium survived on U. intestinalis filaments for at least 2 weeks at 15 and 30 ppt, but the infection did not progress. Sporulation was not observed in the infected algal filaments at any salinity. Conversely, Pythium sporulated on infected grass pieces at 0, 15, and 30 ppt. High salinity retarded sporulation, but did not prevent it. Our Pythium isolate produced filamentous non-inflated sporangia. The sexual stage was never observed and phylogenetic analysis using internal transcribed spacer suggest this isolate belongs to the clade B2. We conclude that the Pythium found in the Oslo fjord was a pathogen of U. intestinalis under low salinity.
Abstract
Utilisable crude protein (uCP), methane (CH4) production and other fermentation parameters were analysed in vitro for a diet in which grass silage was replaced by different levels of seaweed protein fractions prepared from three seaweed species: Saccharina latissima, Alaria esculenta and Palmaria palmata. Ten fractions from these three species in which the protein content had been increased and the salt content reduced by simple processing were tested, with inclusion levels in the diet based on the nitrogen content of the fractions. Following an extraction procedure, four fractions from Saccharina latissima, three from Alaria esculenta and one from Palmaria palmata, were gradually included in the diet by replacing high quality silage with approximately 0, 0.15, 0.30 and 0.45 g/g DM, while two high-protein fractions of Palmaria palmata were tested at replacement levels of 0, 0.075, 0.15 and 0.225 g/g DM. To estimate fermentation parameters, 500 mg of each diet were incubated in bottles with 60 mL buffered rumen fluid. Estimated uCP increased linearly with increasing replacement rate of grass silage with seaweed protein fractions (from 158 g/kg DM to 206 g/kg DM on average for all fractions). Increasing protein fraction from the brown seaweed Saccharina latissima in the diet significantly increased true organic matter digestibility (OMD) (from on average 0.786 to 0.821). Organic matter digestibility decreased with increasing level of Alaria esculenta fractions (from on average 0.785 to 0.733), which also gave a linear decrease in CH4 production (from on average 45.3 to 38.5 mL/g organic matter). As a result of decreased CH4 production and OMD, total volatile fatty acid concentration decreased with increasing level of Alaria esculenta fractions (from on average 69.5 to 63.0 mmol/L). Thus, positive and species-specific effects of seaweed on estimated uCP and fermentation parameters were observed in vitro when protein fractions remaining after an extraction procedure on seaweed partly replaced grass silage in the feed ration.
Authors
Inna Ryzhik Dmitriy Pugovkin Mikhail Makarov Michael Roleda Larisa Basova Grigoriy VoskoboynikovAbstract
The viability and physiological state of brown macroalgae Fucus vesiculosus and its associated epiphytic bacteria exposed to diesel water-accommodated fraction (WAF), as well as the capacity of this association to deplete petroleum hydrocarbons (HCs) were experimentally tested. After a 6-day exposure treatment, the algal-surface associated bacteria were identified as primarily hydrocarbon-oxidising bacteria (HOB), and the algal-HOB association was able to deplete petroleum hydrocarbons from the diesel WAF by 80%. The HOB density on the algal surface exposed to diesel WAF was 350% higher compared to the control (i.e. HOB density on the algal surface exposed to ambient seawater), which suggest that they actively proliferated in the presence of hydrocarbons and most likely consumed hydrocarbons as their primary organic substrate. Exposure to diesel WAF did not affect the metabolic activity of F. vesiculosus. Higher lipid peroxidation was observed in F. vesiculosus exposed to diesel WAF while catalase concentration decreased only during the first day of exposure. Results suggest F. vesiculosus is tolerant to oil pollution and the algal-HOB association can efficiently deplete petroleum hydrocarbons in oil-contaminated seas.
Authors
Ana de la Moneda Maria Dolores Carro Martin Riis Weisbjerg Michael Roleda Vibeke Lind Margarita Novoa-Garrido Eduarda Molina-AlcaideAbstract
This study was designed to analyze the chemical composition and in vitro rumen fermentation of eight seaweed species (Brown: Alaria esculenta, Laminaria digitata, Pelvetia canaliculata, Saccharina latissima; Red: Mastocarpus stellatus, Palmaria palmata and Porphyra sp.; Green: Cladophora rupestris) collected in Norway during spring and autumn. Moreover, the in vitro ruminal fermentation of seventeen diets composed of 1:1 oat hay:concentrate, without (control diet) or including seaweeds was studied. The ash and N contents were greater (p < 0.001) in seaweeds collected during spring than in autumn, but autumn-seaweeds had greater total extractable polyphenols. Nitrogen in red and green seaweeds was greater than 2.20 and in brown seaweeds, it was lower than 1.92 g/kg DM. Degradability after 24 h of fermentation was greater in spring seaweeds than in autumn, with Palmaria palmata showing the greatest value and Pelvetia canaliculata the lowest. Seaweeds differed in their fermentation pattern, and autumn Alaria esculenta, Laminaria digitata, Saccharina latissima and Palmaria palmata were similar to high-starch feeds. The inclusion of seaweeds in the concentrate of a diet up to 200 g/kg concentrate produced only subtle effects on in vitro ruminal fermentation.
Authors
Charlotte Gaillard Hamzah Shahbaz Bhatti Margarita Novoa-Garrido Vibeke Lind Michael Roleda Martin Riis WeisbjergAbstract
The potential of seaweeds as alternative protein source was investigated in relation to their amino acid (AA) profiles and the ruminal and total tract digestibility of these AAs. Three red (Mastocarpus stellatus, Palmaria palmata, and Porphyra sp.), four brown (Alaria esculenta, Laminaria digitata, Pelvetia canaliculata, and Saccharina latissima), and two green (Cladophora rupestris. and Ulva sp.) seaweed species were used in this study (hereafter, referred to by Genus name only). All seaweeds were collected in Bodø, Northern Norway, during Spring and Autumn in 2014 and 2015, except Ulva, which was only sampled in Autumn of both years, and Saccharina which was not sampled in Spring 2014. All the samples were studied for AA concentration. Six species (Cladophora, Laminaria, Mastocarpus, Palmaria, Porphyra and Ulva) were selected for the more resource demanding in situ study. Species and season interactively affected the content of total AA in crude protein in different seaweeds investigated (P=0.02), with values ranging from 67.2 for Laminaria in Spring to 90.2 gAA/16 g N for Ulva in Autumn. in situ AA degradability was also species specific. The seasonality of total AA in crude protein of different seaweed species mostly did not affect their ruminal degradability, except for alanine, while species and season interactively affected proline’s ruminal degradability. The total tract degradability showed that for Laminaria and Mastocarpus, methionine followed by leucine, isoleucine, histidine and lysine, were protected against rumen degradation. These protections seemed to be acid labile allowing digestion in the lower digestive tract. However, due to high indigestible fractions, these two seaweeds provided low amounts of AA to the intestines. Total tract AA digestibility values were the highest for Porphyra (906 g/kg) followed by Palmaria (843 g/kg) and the green seaweeds. To conclude, Laminaria and Mastocarpus are beneficial sources for bypass protein supply as they contain AA protected against rumen degradation. Based on their amount of AA and their AA degradability, Porphyra, followed by Palmaria and the green seaweeds (Ulva and Cladophora) can be considered as relevant sources of protein for ruminants.
Abstract
Carbonic anhydrase (CA) plays an important physiological role in all biological systems by accelerating the interconversion of CO2 and HCO3 −. In algae, CA is essential for photosynthesis: external CA (CAext) dehydrates HCO3 −, enhancing the supply of CO2 to the cell surface, and internal CA (CAint) interconverts HCO3 − and CO2 to maintain the inorganic carbon (Ci) pool and supply CO2 to RuBisCO. We frst conducted a literature review comparing the conditions in which CA extraction and measurement have been carried out, using the commonly used Wilbur–Anderson method. We found that the assay has been widely modifed since its introduction in 1948, mostly without being optimized for the species tested. Based on the review, an optimized protocol for measuring CA in Macrocystis pyrifera was developed, which showed that the assay conditions can strongly afect CA activity. Tris–HCl bufer gave the highest levels of CA activity, but phosphate bufer reduced activity signifcantly. Bufers containing polyvinylpyrrolidone (PVP) and dithiothreitol (DTT) stabilized CA. Using the optimized assay, CAext and CAint activities were readily measured in Macrocystis with higher precision compared to the non-optimized method. The CAint activity was 2×higher than CAext, which is attributed to the Ci uptake mechanisms of Macrocystis. This study suggests that the CA assay needs to be optimized for each species prior to experimental work to obtain both accurate and precise results.
Authors
Bernardo Duarte Irene Martins Rui Rosa Ana R. Matos Michael Roleda Thorsten B. H. Reusch Aschwin H. Engelen Ester A. Serrão Gareth A. Pearson João C. Marques Isabel Caçador Carlos M. Duarte Alexander Oliver JüterbockAbstract
Marine macrophytes are the foundation of algal forests and seagrass meadows–some of the most productive and diverse coastal marine ecosystems on the planet. These ecosystems provide nursery grounds and food for fish and invertebrates, coastline protection from erosion, carbon sequestration, and nutrient fixation. For marine macrophytes, temperature is generally the most important range limiting factor, and ocean warming is considered the most severe threat among global climate change factors. Ocean warming induced losses of dominant macrophytes along their equatorial range edges, as well as range extensions into polar regions, are predicted and already documented. While adaptive evolution based on genetic change is considered too slow to keep pace with the increasing rate of anthropogenic environmental changes, rapid adaptation may come about through a set of non-genetic mechanisms involving the functional composition of the associated microbiome, as well as epigenetic modification of the genome and its regulatory effect on gene expression and the activity of transposable elements. While research in terrestrial plants demonstrates that the integration of non-genetic mechanisms provide a more holistic picture of a species’ evolutionary potential, research in marine systems is lagging behind. Here, we aim to review the potential of marine macrophytes to acclimatize and adapt to major climate change effects via intraspecific variation at the genetic, epigenetic, and microbiome levels. All three levels create phenotypic variation that may either enhance fitness within individuals (plasticity) or be subject to selection and ultimately, adaptation. We review three of the most important phenotypic variations in a climate change context, including physiological variation, variation in propagation success, and in herbivore resistance. Integrating different levels of plasticity, and adaptability into ecological models will allow to obtain a more holistic understanding of trait variation and a realistic assessment of the future performance and distribution of marine macrophytes. Such multi-disciplinary approach that integrates various levels of intraspecific variation, and their effect on phenotypic and physiological variation, is of crucial importance for the effective management and conservation of seagrasses and macroalgae under climate change.
Authors
Pablo P. Leal Catriona L. Hurd Sylvia G. Sander Evelyn Armstrong Pamela A. Fernández Tim J. Suhrhoff Michael RoledaAbstract
Ocean warming (OW), ocean acidification (OA) and their interaction with local drivers, e.g., copper pollution, may negatively affect macroalgae and their microscopic life stages. We evaluated meiospore development of the kelps Macrocystis pyrifera and Undaria pinnatifida exposed to a factorial combination of current and 2100-predicted temperature (12 and 16 °C, respectively), pH (8.16 and 7.65, respectively), and two copper levels (no-added-copper and species-specific germination Cu- EC50). Meiospore germination for both species declined by 5–18% under OA and ambient temperature/ OA conditions, irrespective of copper exposure. Germling growth rate declined by >40%·day−1, and gametophyte development was inhibited under Cu-EC50 exposure, compared to the no-added-copper treatment, irrespective of pH and temperature. Following the removal of copper and 9-day recovery under respective pH and temperature treatments, germling growth rates increased by 8–18%·day−1. The exception was U. pinnatifida under OW/OA, where growth rate remained at 10%·day−1 before and after copper exposure. Copper-binding ligand concentrations were higher in copper-exposed cultures of both species, suggesting that ligands may act as a defence mechanism of kelp early life stages against copper toxicity. Our study demonstrated that copper pollution is more important than global climate drivers in controlling meiospore development in kelps as it disrupts the completion of their life cycle.
Authors
Pierrick Francois Denis Stévant Erlend Indergård Aðalheiður Ólafsdóttir Hélène Marfaing Wenche Merete Emblem Larssen Joël Fleurence Michael Roleda Turid Rustad Rasa Slizyte Tom Ståle NordtvedtAbstract
The effects of convective air-drying at 25, 40, and 70 °C and freeze-drying on the quality of the edible kelp Saccharina latissima to be used for food were investigated. Based on the analysis of the carbohydrate and amino acid profiles, as well as polyphenol, fucoxanthin, and ash contents, no significant differences were detected among sample groups, and air-drying up to 70 °C results in equally nutritious products at shorter processing times. Only the iodine content was found lower in freeze-dried compared to air-dried samples. The swelling capacity of the air-dried samples was significantly lower than in freeze-dried samples, particularly at high temperatures (40 and 70 °C), reflecting alteration of the physico-chemical properties of the seaweed during air-drying (attributed to product shrinkage) and reduced capacity of the final product to rehydrate. Structural differences between air-dried products at 25 and 70 °C may explain the differences in mouthfeel perception (dissolving rate) among the two sample groups observed during a sensory evaluation. Overall, the drying temperature within this range did not alter neither the aroma (i.e. odor) nor the flavor intensity of the product. In food applications where the product’s mechanical properties (e.g. porosity) are essential, freeze-drying, and to a lesser extent, air-drying at low temperatures, will result in higher quality products than air-drying at higher temperatures.
Abstract
A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2// on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose–response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semiquantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes.
Abstract
No abstract has been registered
Authors
Michael Roleda Jorunn Skjermo Hélène Marfaing Rosa Jonsdottir Celine Rebours Anna Gietl Dagmar B. Stengel Udo NitschkeAbstract
This study represents a large-scale investigation into iodine contents in three commercially important and edible seaweed species from the North Atlantic: the brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata. Variability among and within species were explored in terms of temporal and spatial variations in addition to biomass source. Mean iodine concentration in bulk seaweed biomass was speciesspecific: Saccharina > Alaria > Palmaria. Iodine contents of Saccharina biomass were similar between years and seasons, but varied significantly between sampling locations and biomass sources. In Alaria and Palmaria, none of the independent variables examined contributed significantly to the small variations observed. Our data suggest that all three species are rich sources of iodine, and only 32, 283, or 2149 mg dry weight of unprocessed dry biomass of Saccharina, Alaria, or Palmaria, respectively, meets the recommended daily intake levels for most healthy humans.
Authors
Celine Rebours Inga Marie Aasen Ana Karina Carvajal Jan Emblemsvåg Karina Gajardo Jon Halfdanarson Erlend Indergård Alexander Jaramillo Torres Trond Moxness Kortner Åshild Krogdahl Tom Ståle Nordtvedt Hélène Marfaing Annik Fet Magerholm Ronan Pierre Michael Roleda Ingrid Sandbakken Jorunn Skjermo Rasa Slizyte Håvard Steinshamn Pierrick Francois Denis Stévant Wenche Uksnoy Per WaldeAbstract
No abstract has been registered
Authors
Málfríður Bjarnadóttir Björn Viðar Aðalbjörnsson Anna Nilsson Rasa Slizyte Michael Roleda Guðmundur Óli Hreggviðsson Ólafur H. Friðjónsson Rósa JónsdóttirAbstract
The red seaweed Palmaria palmata has previously been reported to have high protein content high in essential amino acids. To extract the proteins a rigid cell wall consisting mainly of β-(1→4)/β-(1→3)-D-xylans must be disrupted. Different methods have been used to overcome this problem along with various methods used for protein evaluation. In this study, the effect of enzymatic pre-treatment on protein extraction was examined. Both enzymatic hydrolysis with xylanase and protease were tested. The amino acid content of the fractions was examined after extraction. The amino acid composition was similar to what has previously been reported; P. palmata was high in essential amino acids. Accordingly, a nitrogen-to-protein conversion factor was calculated for each fraction individually and protein results were compared with calculation using the proximate 6.25 conversion factor. The nitrogen-to-protein conversion factor varied between fractions but all factors were significantly lower than the popularly used 6.25 indicating that this conversion factor for processed P. palmata is effectively and considerably overestimating the protein content. Enzymatic pre-treatment with xylanase resulted in enhanced amino acid content and successful protein extraction. Enzymatic hydrolysis using protease resulted in higher protein content in the liquid extract compared to hydrolysis with xylanase, due to the release of proteins, peptides, and amino acids. Therefore, hydrolysis with protease is not suitable to extract proteins from P. palmata with the method described within this study but might be an optimal method to examine the bioactivity by extracting the protein hydrolysates. However, the result from this study confirm that hydrolysis with xylanase is a feasible choice to extract proteins of good quality from P. palmata.
Authors
Inga Marie Aasen Ingrid Sandbakken Rasa Slizyte Michael Roleda Jorunn Skjermo Åshild KrogdahlAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Michael Roleda Hélène Marfaing Natasa Desnica Rósa Jónsdóttir Jorunn Skjermo Celine Rebours Udo NitschkeAbstract
Seaweeds are increasingly used in European cuisines due to their nutritional value. Many algal constituents, such as polyphenols, are important antioxidants and thus considered beneficial to humans. However, many seaweed species can accumulate heavy metals and exhibit potential health risks upon ingestion. We investigated temporal and spatial variations in polyphenol and heavy metal (As, Cd, Hg, Pb) concentrations of three edible seaweed species. The brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata were sourced from natural populations and aquaculture in the NE Atlantic and processed as bulk biomass mimicking industrial scales. The mean polyphenol content was species-specific (Alaria > Saccharina > Palmaria), and highest in winter (for Alaria and Saccharina) and spring (for Palmaria); inter-annual and spatial variations were marginal. Heavy metal concentrations varied between species and depended on collection site, but seasonal variations were minimal. Our data suggest that all three species are good sources of antioxidants, and the heavy metal concentrations are below the upper limits set by the French recommendation and the EU Commission Regulation on contaminants in foodstuffs. A health risk assessment indicated that consumption of these seaweed species poses a low risk for humans with regard to heavy metals. However, an EU-wide regulation on maximal concentration of heavy metals in seaweeds should be established.
Abstract
No abstract has been registered
Authors
Mohammad Ramin Marcia De Oliveira Franco Michael Roleda Inga Marie Aasen Mårten Hetta Håvard SteinshamnAbstract
No abstract has been registered
Abstract
We conducted a series of diagnostic fitness response experiments on the coccolithophore, Emiliania huxleyi, isolated from the Subtropical Convergence east of New Zealand. Dose response curves (i.e., physiological rate vs. environmental driver) were constructed for growth, photosynthetic, and calcification rates of E. huxleyi relative to each of five environmental drivers (nitrate concentration, phosphate concentration, irradiance, temperature, and pCO2). The relative importance of each environmental driver on E. huxleyi rate processes was then ranked using a semi-quantitative approach by comparing the percentage change caused by each environmental driver on the measured physiological metrics under the projected conditions for the year 2100, relative to those for the present day, in the Subtropical Convergence. The results reveal that the projected future decrease in nitrate concentration (33%) played the most important role in controlling the growth, photosynthetic and calcification rates of E. huxleyi, whereas raising pCO2 to 75 Pa (750 ppm) decreased the calcification : photosynthesis ratios to the greatest degree. These findings reveal that other environmental drivers may be equally or more influential than CO2 in regulating the physiological responses of E. huxleyi, and provide new diagnostic information to better understand how this ecologically important species will respond to the projected future changes to multiple environmental drivers.
Authors
Steffen Werne Felix Heckendorn Michael Roleda L Baumgartner Eduarda Molina-Alcaide A Drewek Vibeke LindAbstract
No abstract has been registered
Authors
Eduarda Molina-Alcaide Maria Dolores Carro Michael Roleda Martin Riis Weisbjerg Vibeke Lind Margarita Novoa-GarridoAbstract
Seaweeds have potentials as alternative feed for ruminants, but there is a limited knowledge on their nutritive value. Seven seaweed species collected along the coast above the Arctic circle of Norway, both in spring and autumn, were assessed for nutrients and total polyphenols (TEP) content, gas production kinetics and in vitro rumen fermentation in batch cultures of ruminal microorganisms. The seaweeds were three red species (Mastocarpus stellatus, Palmaria palmata and Porphyra sp.), three brown species (Alaria esculenta, Laminaria digitata and Pelvetia canaliculata) and one green species (Acrosiphonia sp.). Additionally, the abundance and diversity of total bacteria, protozoa and archaea in the cultures with the three red seaweeds collected in spring were analyzed by quantitative PCR and PCR-DGGE, respectively. The crude protein (CP) content varied widely. Pelvetia had the greatest (P < 0.001) ether extract (EE) content. Non-structural carbohydrates (NSC) content varied from 135 to 541 g/kg DM with brown seaweeds having the greatest values. Ash and CP contents were higher in spring than in autumn (P = 0.020 and 0.003, respectively), whereas concentrations of EE and NSC were not affected by collecting season (P = 0.208–0.341). The TEP values ranged from 1.46 to 50.3 mg/g dry matter (DM), and differed (P < 0.001) among seaweed species and collecting season, being greater in autumn than in spring. The DM effective degradability (DMED), estimated from gas production parameters for a rumen passage rate of 3.0% per h, ranged from 424 to 652 g/kg, the highest values were recorded for Mastocarpus stellatus and Porphyra sp. The lowest DMED values were registered for Pelvetia canaliculata and Acrosiphonia sp. In 24-h incubations (500 mg DM), Palmaria palmata had the highest (P < 0.05) volatile fatty acids (VFA) and methane production (4.34 and 0.761 mmol, respectively) and the lowest (P < 0.05) final pH values and acetate to propionate ratios (6.57 and 2.34, respectively). There were no differences (P > 0.05) among the other seaweeds in VFA production, but Porphyra sp. had the second highest methane production (P < 0.05; 0.491 mmol) compared with the other seaweeds (0.361 mmol; averaged value). The methane/total VFA ratio was not affected (P > 0.05) by either seaweed species or the collection season. Higher final pH (P < 0.05) and lower (P < 0.05) methane and VFA production, ammonia-N concentrations and DMED values were promoted by the fermentation of seaweed collected in autumn compared with those from spring. Among the red seaweeds, there were no species-specific differences (P > 0.05) in the abundance or the diversity of total bacteria, protozoa and archaea. In the PCR-DGGE analysis, samples were separated by the incubation run for all microbial populations analyzed, but not by seaweed species. The results indicate that seaweed species differ markedly in their in vitro rumen degradation, and that samples collected in autumn had lower rumen degradability than those collected in spring.
Authors
Michael Roleda Udo Nitscke Anna Gietl Celine Rebours Jorunn Skjermo Hélène Marfaing Ronan Pierre Annelise Sabine Chapman Dagmar StengelAbstract
No abstract has been registered
Abstract
Anthropogenic atmospheric emissions of CO2 are responsible for simultaneous ocean warming (OW) and ocean acidification (OA). These global events can have important impacts on marine fleshy macroalgae and coastal ecosystems. To understand the effects of OW and OA on the early life history stages of native (Macrocystis pyrifera) and invasive (Undaria pinnatifida) macroalgae, a multi-factorial experiment was performed to determine the independent and interactive effects of the drivers and the corresponding species-specific responses. Meiospores of M. pyrifera and U. pinnatifida were separately exposed to a 4 × 2 factorial design of seawater pH (pHT 7.20, extreme OA predicted for 2300; pHT 7.65, OA predicted for 2100; pHT 8.03, ambient pH; and pHT 8.40, pre-industrial pH) and temperature (12 °C, seasonal average temperature; and 16 °C, OW predicted for 2100). Over 15 days, different physiological parameters (i.e. meiospore germination, germling growth rate, gametophyte development and sex ratio) were measured. Reduced seawater pH and elevated temperature had independent and significant effects on developmental processes (germling growth rate, and male and female gametophyte sizes were independently greater under OA and OW conditions), but the interaction of the abiotic factors had no effect on any stage of meiospore development of either species. Despite some small differences between species (e.g. sex ratio), results of this experiment suggest that microscopic stages of the native M. pyrifera and the invasive U. pinnatifida will respond similarly to OA and OW.
Abstract
The absorption of anthropogenic CO 2 by the oceans is causing a reduction in the pH of the surface waters termed ocean acidification (OA). This could have substantial effects on marine coastal environments where fleshy (non-calcareous) macroalgae are dominant primary producers and ecosystem engineers. Few OA studies have focused on the early life stages of large macroalgae such as kelps. This study evaluated the effects of seawater pH on the ontogenic development of meiospores of the native kelp Macrocystis pyrifera and the invasive kelp Undaria pinnatifi da , in south-eastern New Zealand. Meiospores of both kelps were released into four seawater pH treatments (pH T 7.20, extreme OA predicted for 2300; pH T 7.65, OA predicted for 2100; pH T 8.01, ambient pH; and pH T 8.40, pre-industrial pH) and cultured for 15 d. Meiospore germination, germling growth rate, and gametophyte size and sex ratio were monitored and measured. Exposure to reduced pH T (7.20 and 7.65) had pos itive effects on germling growth rate and gametophyte size in both M. pyrifera and U. pinnatifida , whereas, higher pH T (8.01 and 8.40) reduced the gametophyte size in both kelps. Sex ratio of gametophytes of both kelps was biased toward females under all pH T treatm ents, except for U. pinnatifida at pH T 7.65. Germling growth rate under OA was significantly higher in M. pyrifera compared to U. pinnatifida but gametophyte development was equal for both kelps under all seawater pH T treatments, indicating that the microscopic stages of the native M. pyrifera and the invasive U. pinnatifida will respond similarly to OA.
Authors
Rosa Jonsdottir Adalheidur Ólafsdottir Björn Viðar Aðalbjörnsson Málfríður Bjarnadóttir Inga Marie Aasen Rasa Slizyte Michael Roleda Jorunn Skjermo Hélène Marfaing Pierrick Francois Denis Stévant Celine ReboursAbstract
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Authors
Celine Rebours Pierrick Francois Denis Stévant Erik Olav Gracey Liv Guri Velle Michael Roleda Håvard Steinshamn Hélène Marfaing Inga Marie Aasen Åshild Krogdahl Tom Ståle Nordtvedt Johan Oppen Ana Karina Carvajal Silje Forbord Kristine Steinhovden Aleksander Handå Jorunn Skjermo Rasa Slizyte oddvar skarbø Mohammad Ramin Annelise Sabine ChapmanAbstract
The 2015-2018 PROMAC (Energy efficient Processing of Macroalgae in blue-green value chains) is financed by the Norwegian Research Council. The PROMAC consortium is led by Møreforsking AS and consists of both Norwegian (SINTEF, NIBIO, NTNU, NMBU) and European (CEVA, MATIS, SLU)research institutes, as well as industrial partners (TafjordKraftvarme, FelleskjøpetFôrutvikling, Firmenich, LegaseaBiomarine Cluster, The Northern Company, Orkla Foods, Hortimare, Marinox).An advisory panel with public authority and interest groups from the marine, energy and agricultural sectors, also oversee the 4,5Mill EUR project’s relevance in a societal context.The current approaches to meeting the demands for meat and other protein-rich food sources are often associated with damage to natural resources and negative effects on climate, air quality, soils and fresh water availability. Therefore, the PROMAC project (http://promac.no/) investigates an alternative approach for providing food and sources of proteins and energy in animal feed, and health benefits in human food through cultivation of macroalgae. The project focuses on the three macroalgaespecies Alariaesculenta, Saccharinalatissima andPalmariapalmata.The research project (i) assesses variation of raw material composition and quality from both harvested and cultured macroalgae, (ii) develops primary processing methods enhancing desired raw material properties, (iii) establishes fractionation and extraction methods best suited to enrich beneficial proteins or remove undesirable anti-nutrients and (iv) evaluates nutritional and health values of processed macroalgal ingredients for various animal groups and in relation to their distinct digestive systems.PROMAC assesses the costs and benefits of macroalgal products from a value chain perspective (from raw material to primary market) through process-based Life Cycle Assessment (LCA), Material and Energy Flow Analysis (MEFA) and business models. To reduce the substantial energy required for primary processing of macroalgae - organisms characterized by ahigh-water content - PROMAC includes a case study utilizing excess heat from a waste incinerator for primary drying and processing of macroalgae biomass. This case study is integrated into both environmental and economic models.Initialresults identifyingmacroalgae food and feed products (ingredients)and associatedprocessing methods most relevant for commercial applications, will be presented integrated across work packages and subject fields.
Abstract
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Authors
Xiaojie Liu Kenny Bogaert Aschwin H. Engelen Frederik Leliaert Michael Roleda Olivier De ClerckAbstract
Knowledge of life cycle progression and reproduction of seaweeds transcends pure academic interest. Successful and sustainable seaweed exploitation and domestication will indeed require excellent control of the factors controlling growth and reproduction. The relative dominance of the ploidy-phases and their respective morphologies, however, display tremendous diversity. Consequently, the ecological and endogenous factors controlling life cycles are likely to be equally varied. A vast number of research papers addressing theoretical, ecological and physiological aspects of reproduction have been published over the years. Here, we review the current knowledge on reproductive strategies, trade-offs of reproductive effort in natural populations, and the environmental and endogenous factors controlling reproduction. Given that the majority of ecophysiological studies predate the “-omics” era, we examine the extent to which this knowledge of reproduction has been, or can be, applied to further our knowledge of life cycle control in seaweeds.
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Authors
Michael RoledaAbstract
No abstract has been registered
Abstract
The production of accurate and reliable data on copper ecotoxicology of marine algae depends on the use of trace metal clean techniques during experimentation. We reviewed the methodologies used in the literature on copper ecotoxicology of marine macro- and microalgae, specifically the use of trace metal clean procedures such as the labware used (glassware vs. plasticware), methods of cleaning the labware (acid soaking and ultrapure water rinsing), stock solution preparation (copper source and acidification), and measurement and reporting of dissolved copper concentrations. In terms of taxonomic classification, the most studied algal groups were the Phyla Ochrophyta, Bacillariophyta, Rhodophyta, and Chlorophyta. In terms of methodology, ∼50% of the articles did not specify the labware, ∼25% used glassware, and ∼25% plasticware; ∼30% of the studies specified cleaning protocols for labware to remove trace metal impurities; the copper form used to prepare the stock solutions was specified in ∼80% of studies but acidification to stabilise the dissolved copper was performed in only ∼20%; and the dissolved copper concentration was measured in only ∼40% of studies. We discuss the importance of following trace metal clean techniques for the comparison and interpretation of data obtained on copper ecotoxicology in algae.
Authors
Jorunn Skjermo Silje Forbord Aleksander Handå Kristine Steinhovden Vera Kristinova Rasa Slizyte Sophie Fische Michael Roleda Rosa Jonsdottir Ronan PierreAbstract
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Authors
Jorunn Skjermo Silje Forbord Aleksander Handå Kristine Steinhovden Vera Kristinova Rasa Slizyte Sophie Fische Michael Roleda Rosa Jonsdottir Ronan PierreAbstract
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Copper in low natural concentrations is essential for cell metabolism but in excess it becomes extremely toxic to aquatic life, including to the early life stages of marine macroalgae. This work determined the effects of copper exposure on meiospore development of two kelp species, the native Macrocystis pyrifera and invasive Undaria pinnatifida. After settlement, meiospores were exposed to nominal copper concentrations of control (no added copper), 100, 200, 300 and 400 μg L−1 Cu for 9 days. Inductively coupled plasma mass spectrometry of total dissolved copper (CuT) concentrations in the blanks showed that nominal copper concentrations were reduced to 54, 91, 131 and 171 μg L−1 CuT, respectively, indicating that > 50% of the dissolved copper was adsorbed onto the culture vessel walls. In the media with meiospores, the dissolved copper concentrations decreased to 39, 86, 97 and 148 μg L−1 CuT in M. pyrifera and to 39, 65, 97 and 146 μg L−1 CuT in U. pinnatifida, indicating that 6–15% of the dissolved copper was adsorbed by the cells. For both species, meiospores germinated in all copper treatments, with germination decreasing with increasing copper concentration. However, gametophyte growth and sexual differentiation were arrested under all copper treatments. The effective copper concentration causing 50% of arrested germination (Cu-EC50) was 157 and 231 μg L−1 CuT for M. pyrifera and U. pinnatifida, respectively. The higher Cu-EC50 for U. pinnatifida suggests ecological success for the invasive species in copper-polluted environments; however, the subsequent inhibition of gametogenesis under all copper treatments indicated no difference in copper tolerance between both kelp early life stages. We compare our results with the literature available on the effects of copper on the development of early life stages of brown seaweed (Laminariales and Fucales) and discuss the importance of reporting actual experimental dissolved copper concentrations and the necessity of standardizing the response variables measured in macroalgal copper ecotoxicology.
Authors
Martin Riis Weisbjerg Margarita Novoa Garrido Michael Roleda Eduarda Molina-Alcaide Vibeke LindAbstract
No abstract has been registered
Abstract
The use of seaweeds in animal diets is not new. However, little is known about the feed value of seaweed, both in terms of chemical composition and protein digestibility, and regarding variation between species and season. In this study, eight seaweed species of the genus Acrosiphonia, Alaria, Laminaria, Mastocarpus, Palmaria, Pelvetia, Porphyra, and Ulva were sampled in spring (March) and autumn (October and November) 2014 at the coast of Bodø in Northern Norway, and were analysed for chemical composition, in situ rumen degradability and total tract crude protein (CP) digestibility. Ash content in dry matter (DM) was generally high (overall mean 190 g/kg in DM) and varied considerably, between species (P < 0.01) and between seasons (P = 0.02). CP concentration in DM varied both between species (P < 0.0001) and seasons (P < 0.01). Highest CP in DM was found for Porphyra (350 g/kg DM) and lowest for Pelvetia (90 g/kg DM). Spring samples were higher in CP than autumn samples. The effective degradability estimated at 5% rumen passage rate (ED5) of CP varied between species (P < 0.0001) but not between seasons (P = 0.10). The highest ED5 of CP was found for Alaria (550 g/kg CP) and lowest for Ulva (240 g/kg CP). Digestible rumen escape protein (DEP) varied significantly between species (P < 0.0001) but not between seasons (P = 0.06); highest DEP was found for Ulva (530 g/kg CP) and Porphyra (500 g/kg CP). Based on our results, Acrosiphonia, Alaria, Laminaria, Mastocarpus and Palmaria can supply the rumen with high amounts of rumen degradable protein, while Porphyra and Ulva can be used as a source of digestible bypass protein. Pelvetia had a very low degradability and should not be used to feed dairy cows.
Authors
Ingrid Agathe Bay-Larsen Ingebjørg Vestrum Vibeke Lind Camilla Risvoll Margarita Novoa Garrido Michael RoledaAbstract
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Authors
Ingrid Agathe Bay-Larsen Ingebjørg Vestrum Vibeke Lind Camilla Risvoll Margarita Novoa Garrido Michael RoledaAbstract
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Authors
Rafael Bermúdez Yuanyuan Feng Michael Roleda Avery O. Tatters David A. Hutchins Thomas Larsen Philip W. Boyd Catriona L. Hurd Ulf Riebesell Monika WinderAbstract
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Authors
Ralf Rautenberger Pamela A. Fernández Martina Strittmatter Svenja Heesch Christopher E. Cornwall Catriona L. Hurd Michael RoledaAbstract
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Authors
Michael RoledaAbstract
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Authors
Michael Roleda Maria Herrero Celine Rebours Erik Lysøe Christian Guido Bruckner Marte Meland Merete Dees Dag-Ragnar Blystad Stig A. Borgvang Åsbjørn Karlsen Arne Hermansen Margarita Novoa-GarridoAbstract
No abstract has been registered
Authors
Michael Roleda Maria Herrero Celine Rebours Erik Lysøe Christian Guido Bruckner Marte Meland Merete Dees Dag-Ragnar Blystad Stig A. Borgvang Åsbjørn Karlsen Arne Hermansen Margarita Novoa-GarridoAbstract
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