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To investigate phytoplankton dynamics in response to variable winter weather conditions along the Sea of Japan, we conducted daily sampling in enclosed Maizuru Bay in five winters and found distinctive differences between 2016/2017 and 2018/2019. A clear diatom bloom occurred through the water column in moderately cold/snowy 2016/2017, whereas in exceptionally warm/snow-free 2018/2019 a small peak of dinoflagellates occurred only in the subsurface. Nutrient concentrations changed drastically depending on freshwater discharge and diatom growth in 2016/2017, showing a contrast with constant nutrient concentrations in 2018/2019. Copepod densities were ~10 times higher in 2016/2017 than in 2018/2019, indicating bottom-up effects in 2016/2017. As the absence of a diatom bloom from 2018/2019 can be attributed neither to nutrient limitation nor to grazing pressure, we hypothesize that wind mixing is a key factor triggering a diatom bloom. Within the five winters, clear diatom blooms were found only after strong winds and heavy precipitation including snowfall. Wind mixing would possibly promote the germination/rejuvenation of viable resting stage cells as inocula for a diatom bloom, while the growth and maintenance are supported by nutrient supply through freshwater discharge. In Maizuru Bay, winter production is likely activated by harsh weather conditions characteristic of this region.

La Paz Bay (LPB) considered one of the most highly productive bays in the southwestern Gulf of California, Mexico, recently established as Priority Marine Region, supports many species of ecological importance. In this context, daily composites of surface chlorophyll a (Chl-aSAT), sea surface temperature (SST) satellite images derived from the MODIS-Aqua sensor, and a wind intensity index (WI) calculated with data recorded simultaneously at four points along the coast, were used to describe the strong 2015–2016 El Niño impact over the surface chlorophyll pigments in LPB, relative to its average for 2003–2013. Significant relationships between SST, WI (used as environmental factors) and Chl-aSAT (RSST = −0.74, RWI = −0.40, P < 0.01) were found using exponential models for the entire study period, with moderate correlation during El Niño winter condition (December 2015 to March 2016) between SST and Chl-aSAT (RSST = 0.45, P < 0.02). The Chl-aSAT showed unexpectedly low values (∼0.5–1.2 mg m−3) with one month-lag of the winter bloom period jointly with the presence of warmer-than-usual water (∼1.0 °C) and episodes of strong northwesterly winds (speed 8.0–10.0 m s−1) that began in autumn that drove a ∼2 month-lag in its winter peak. The Chl-aSAT and SST winter spatial patterns, showed low Chl-aSAT values (∼−0.5 to −1.0 mg m−3) along the bay and higher-than-usual SST by ∼ 0.5–1.0 °C relative to a year under the La Niña winter condition (2017–2018). This triggered the possible thermocline deepening and the lowest levels of nutrient supply to the photic layer during the El Niño winter episode. Hovmöller diagrams of Chl-aSAT and SST anomalies along the coast revealed a sharp drop to negative anomaly values (∼− 0.7 to −1.2 mg m−3), in-phase but negatively correlated with the SST coastal anomalies (R = − 0.88, P < 0.01). This biophysical coupling played a crucial role in the exceptional drop to the lowest winter Chl-aSAT levels seen in LPB since the MODIS satellite sensor beg

Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49, (2022): e2021GL096180, https://doi.org/10.1029/2021gl096180., In the subtropical gyres, phytoplankton rely on eddies for transporting nutrients from depth to the euphotic zone. But, what controls the rate of nutrient supply for new production? We show that vertical nutrient flux both depends on the vertical motion within the eddying flow and varies nonlinearly with the phytoplankton growth rate. Flux is maximized when the growth rate matches the inverse of the decorrelation timescale for vertical motion. Using a three-dimensional ocean model and a linear nutrient uptake model, we find that phytoplankton productivity is maximized for a growth rate of 1/3 day−1, which corresponds to the timescale of submesoscale dynamics. Variability in the frequency of vertical motion across different physical features of the flow favors phytoplankton production with different growth rates. Such a growth-transport feedback can generate diversity in the phytoplankton community structure at submesoscales and higher net productivity in the presence of community diversity., MAF and AM were funded by N00014-16-1-3130 (ONR) and MAF was also supported by the Martin Fellowship, MIT., 2022-07-20

Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49, (2022): e2021GL096180, https://doi.org/10.1029/2021gl096180., In the subtropical gyres, phytoplankton rely on eddies for transporting nutrients from depth to the euphotic zone. But, what controls the rate of nutrient supply for new production? We show that vertical nutrient flux both depends on the vertical motion within the eddying flow and varies nonlinearly with the phytoplankton growth rate. Flux is maximized when the growth rate matches the inverse of the decorrelation timescale for vertical motion. Using a three-dimensional ocean model and a linear nutrient uptake model, we find that phytoplankton productivity is maximized for a growth rate of 1/3 day−1, which corresponds to the timescale of submesoscale dynamics. Variability in the frequency of vertical motion across different physical features of the flow favors phytoplankton production with different growth rates. Such a growth-transport feedback can generate diversity in the phytoplankton community structure at submesoscales and higher net productivity in the presence of community diversity., MAF and AM were funded by N00014-16-1-3130 (ONR) and MAF was also supported by the Martin Fellowship, MIT., 2022-07-20

Inland waterbodies play an important role in the global carbon cycle, acting both as carbon sources with organic carbon (OC) mineralization and as sinks with OC burial in sediments. Under recent impacts of global warming, anthropogenic land-use change and nutrient supply, however, there is a limited knowledge regarding OC dynamics in sediments of large, deep lakes especially in subtropical alpine regions. Here, we studied the patterns of OC burial and the potential regulating factors using multiple sedimentary proxies and observational records in Lugu Lake (southwest China) over the past ~100 years. Comparisons of 15 sediment cores in different areas of the lake reveal similar temporal trends in OC content and other sediment parameters, indicating coherent patterns of whole-lake sedimentary environmental change dominated by watershed human perturbation. Based on C/N ratios and δ13Corg analyses, the sediment OC has primarily been autochthonous in source. OC accumulation rates (OCAR) increased during 1880–1980, from ~14 to 43 g C m−2 yr−1 in a central core (LGS), mainly resulting from elevated primary production under increased phosphorus input and soil erosion. Subsequently, OCAR decreased considerably to ~15 g C m−2 yr−1, although the phosphorus supply and lake primary productivity remained high. We infer the OCAR decline likely resulted from increased organic matter decomposition and OC mineralization in the water column because of climate warming and lake-water thermal stratification. This phenomenon might mask the positive contribution of primary production to OC burial. Our findings suggest that the commonly observed synergistically positive effects of warming and eutrophication on sediment OC burial may be impaired in deep lakes, which needs further investigations across ecological, climatic and land-use gradients.

Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most oligotrophic waters in the subtropical North Atlantic, using transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated, firstly, from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation and, secondly, using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. The diapycnal transfer provides a nutrient supply within the euphotic zone, but induces a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrien

Grain corn is the main cereal produced in Portugal. It is grown in intensive monoculture cropping systems that may have negative effects on soil quality, affecting long-term fertility and productivity, and, therefore, the sustainability of the production. A promising management practice to mitigate soil degradation is to grow winter cover crops used as green manure. This study examined the effectiveness of six legume cover crops (LCCs) species in providing agro-ecological services for grain corn systems in the Mediterranean region, specifically in terms of nutrient leaching, nutrient recycling, weed control, and soil fertility. The study was performed in Central Portugal during 2 years, and it assessed legumes/weeds dry biomass yield, their nutrients content, and soil organic matter evolution. Results show that, in general, LCC are well adapted to Mediterranean conditions, yielding large amounts of biomass (up to 8 ton/ha for some clover species). In terms of nutrient leaching mitigation, the overall N-P-K nutrient uptake was 176-20-172 kg/ha. Green manure services enabled a reduction of 35% of N, 50% of P, and 100% of mineral fertilizers for a grain corn production of 12 ton/ha. Weed control by LCC was effective only in the second year of the study and for three clover species (crimson, balansa, and arrowleaf) due to their early establishment and/or high biomass production competing with weeds. Soil fertility was not improved in the short term, LCC incorporation into the soil to a slight depletion of the soil organic matter content., QC 20220110

Grain corn is the main cereal produced in Portugal. It is grown in intensive monoculture cropping systems that may have negative effects on soil quality, affecting long-term fertility and productivity, and, therefore, the sustainability of the production. A promising management practice to mitigate soil degradation is to grow winter cover crops used as green manure. This study examined the effectiveness of six legume cover crops (LCCs) species in providing agro-ecological services for grain corn systems in the Mediterranean region, specifically in terms of nutrient leaching, nutrient recycling, weed control, and soil fertility. The study was performed in Central Portugal during 2 years, and it assessed legumes/weeds dry biomass yield, their nutrients content, and soil organic matter evolution. Results show that, in general, LCC are well adapted to Mediterranean conditions, yielding large amounts of biomass (up to 8 ton/ha for some clover species). In terms of nutrient leaching mitigation, the overall N-P-K nutrient uptake was 176-20-172 kg/ha. Green manure services enabled a reduction of 35% of N, 50% of P, and 100% of mineral fertilizers for a grain corn production of 12 ton/ha. Weed control by LCC was effective only in the second year of the study and for three clover species (crimson, balansa, and arrowleaf) due to their early establishment and/or high biomass production competing with weeds. Soil fertility was not improved in the short term, LCC incorporation into the soil to a slight depletion of the soil organic matter content.

Sustaining biological export over the open ocean requires a physical supply of nutrients to the mixed layer and thermocline. The relative importance of diapycnal mixing, diapycnal advection and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in oligotrophic waters in the subtropical North Atlantic, consisting of transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation, and using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing, diapycnal advection and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. Diapycnal mixing and advection provide a nutrient supply within the euphotic zone, but a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone, and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical sup

Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most oligotrophic waters in the subtropical North Atlantic, using transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated, firstly, from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation and, secondly, using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. The diapycnal transfer provides a nutrient supply within the euphotic zone, but induces a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrien

Ruminant livestock maintain an important role in meeting the nutrient requirements of the global population through their unique ability to convert plant fiber into human-edible meat and milk products. Volatile fatty acids (VFA) produced by rumen microbial fermentation of feed substrates represent around 70% of the ruminant animal's metabolic energy supply. Rumen fermentation profiles may directly impact productivity because the types of VFA produced are utilized at differing efficiencies by the animal. Improving our understanding of factors that control these fermentative outcomes would therefore aid in optimizing the productive efficiency of ruminant livestock. Improvements in animal efficiency are now more important than ever as the livestock industry must adapt to continue meeting the nutritional needs of a growing global population in the context of increased resource restrictions and requirements to lower the environmental impact of production. The relationship between diet and VFA ultimately supplied to the animal is complex and poorly understood due to the influence of numerous nutritional, biochemical, and microbial variables. The central aim of this body of work was therefore to explore and characterize how fermentation dynamics, rumen environmental characteristics, and the rumen microbiome behave in response to variations in the supply of fermentative substrate. The objective of our first experiment was to describe a novel in vitro laboratory technique to rank livestock feeds based on their starch degradability. This experiment also compared the starch degradation rates estimated by the in vitro method to the rates estimated by a traditional in situ method using sheep. A relationship between the degradation rates determined by these two procedures was observed, but only when feed nutrient content was accounted for. While this in vitro approach may not be able to reflect actual ruminal starch degradation rates, it holds potential as a useful laboratory tec

Sustaining biological export over the open ocean requires a physical supply of nutrients to the mixed layer and thermocline. The relative importance of diapycnal mixing, diapycnal advection and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in oligotrophic waters in the subtropical North Atlantic, consisting of transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation, and using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing, diapycnal advection and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. Diapycnal mixing and advection provide a nutrient supply within the euphotic zone, but a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone, and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical sup

Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most oligotrophic waters in the subtropical North Atlantic, using transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated, firstly, from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation and, secondly, using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. The diapycnal transfer provides a nutrient supply within the euphotic zone, but induces a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrien

Grain corn is the main cereal produced in Portugal. It is grown in intensive monoculture cropping systems that may have negative effects on soil quality, affecting long-term fertility and productivity, and, therefore, the sustainability of the production. A promising management practice to mitigate soil degradation is to grow winter cover crops used as green manure. This study examined the effectiveness of six legume cover crops (LCCs) species in providing agro-ecological services for grain corn systems in the Mediterranean region, specifically in terms of nutrient leaching, nutrient recycling, weed control, and soil fertility. The study was performed in Central Portugal during 2 years, and it assessed legumes/weeds dry biomass yield, their nutrients content, and soil organic matter evolution. Results show that, in general, LCC are well adapted to Mediterranean conditions, yielding large amounts of biomass (up to 8 ton/ha for some clover species). In terms of nutrient leaching mitigation, the overall N-P-K nutrient uptake was 176-20-172 kg/ha. Green manure services enabled a reduction of 35% of N, 50% of P, and 100% of mineral fertilizers for a grain corn production of 12 ton/ha. Weed control by LCC was effective only in the second year of the study and for three clover species (crimson, balansa, and arrowleaf) due to their early establishment and/or high biomass production competing with weeds. Soil fertility was not improved in the short term, LCC incorporation into the soil to a slight depletion of the soil organic matter content.

In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in time (several weeks) and space (hundreds of km) from island‐driven nutrient supply. This study suggests that the fertilizing effect of islands on phytoplankton may have been largely underestimated. Plain language summary In the poor and nutrient‐depleted waters of the tropical Pacific, islands act as sources of nutrients fertilizing nearby waters. These nutrients are consumed by microscopic photosynthesizing algae, the phytoplankton. The resulting phytoplankton enrichments (blooms) in turn support productive ecosystems. This phenomenon, termed the “island mass effect”, has been known for sixty years and is classically defined by increased chlorophyll (representing phytoplankton biomass) next to an island. Blooms also occur in the open ocean and are usually attributed to vertical processes such as mixing or uplifting that locally supply nutrients from subsurface reservoirs. In this paper, we demonstrate that a different type of island mass effect exists, where the phytoplankton response is delayed because they grow very slowly. These blooms are supported by the nitrogen fixer Trichodesmium. Since phytoplankton get carried away from islands by oceanic currents while they grow, this can lead to a bloom located hundred

In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in time (several weeks) and space (hundreds of km) from island‐driven nutrient supply. This study suggests that the fertilizing effect of islands on phytoplankton may have been largely underestimated. Plain language summary In the poor and nutrient‐depleted waters of the tropical Pacific, islands act as sources of nutrients fertilizing nearby waters. These nutrients are consumed by microscopic photosynthesizing algae, the phytoplankton. The resulting phytoplankton enrichments (blooms) in turn support productive ecosystems. This phenomenon, termed the “island mass effect”, has been known for sixty years and is classically defined by increased chlorophyll (representing phytoplankton biomass) next to an island. Blooms also occur in the open ocean and are usually attributed to vertical processes such as mixing or uplifting that locally supply nutrients from subsurface reservoirs. In this paper, we demonstrate that a different type of island mass effect exists, where the phytoplankton response is delayed because they grow very slowly. These blooms are supported by the nitrogen fixer Trichodesmium. Since phytoplankton get carried away from islands by oceanic currents while they grow, this can lead to a bloom located hundred

In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in time (several weeks) and space (hundreds of km) from island‐driven nutrient supply. This study suggests that the fertilizing effect of islands on phytoplankton may have been largely underestimated. Plain language summary In the poor and nutrient‐depleted waters of the tropical Pacific, islands act as sources of nutrients fertilizing nearby waters. These nutrients are consumed by microscopic photosynthesizing algae, the phytoplankton. The resulting phytoplankton enrichments (blooms) in turn support productive ecosystems. This phenomenon, termed the “island mass effect”, has been known for sixty years and is classically defined by increased chlorophyll (representing phytoplankton biomass) next to an island. Blooms also occur in the open ocean and are usually attributed to vertical processes such as mixing or uplifting that locally supply nutrients from subsurface reservoirs. In this paper, we demonstrate that a different type of island mass effect exists, where the phytoplankton response is delayed because they grow very slowly. These blooms are supported by the nitrogen fixer Trichodesmium. Since phytoplankton get carried away from islands by oceanic currents while they grow, this can lead to a bloom located hundred

Vegetarian diets have gained popularity in sports. However, few data exist on the status of micronutrients and related biomarkers for vegetarian and vegan athletes. The aim of this cross-sectional study was to compare the micronutrient status of omnivorous (OMN, n = 27), lacto-ovo-vegetarian (LOV, n = 26), and vegan (VEG, n = 28) recreational runners. Biomarkers of vitamin B12, folate, vitamin D, and iron were assessed. Additionally, serum levels of calcium, magnesium, and zinc were examined. Lifestyle factors and supplement intake were recorded via questionnaires. About 80% of each group showed vitamin B12 adequacy with higher levels in supplement users. Mean red blood cell folate exceeded the reference range (>340 nmol/L) in all three groups (OMN: 2213 ± 444, LOV: 2236 ± 596, and VEG: 2354 ± 639 nmol/L; not significant, n.s.). Furthermore, vitamin D levels were comparable (OMN: 90.6 ± 32.1, LOV: 76.8 ± 33.7, and VEG: 86.2 ± 39.5 nmol/L; n.s.), and we found low prevalence (<20%) of vitamin D inadequacy in all three groups. Less than 30% of each group had depleted iron stores, however, iron deficiency anemia was not found in any subject. Our findings suggest that a well-planned, health-conscious lacto-ovo-vegetarian and vegan diet, including supplements, can meet the athlete’s requirements of vitamin B12, vitamin D and iron. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.

Background The number of people preferring plant-based nutrition is growing continuously in the western world. Vegetarianism and veganism are also becoming increasingly popular among individuals participating in sport. However, whether recreationally active vegetarian and vegan populations can meet their nutritional needs is not clear. Methods The purpose of this cross-sectional study was to compare the nutrient intake of omnivorous (OMN, n = 27), lacto-ovo vegetarian (LOV, n = 25) and vegan (VEG, n = 27) recreational runners (two to five training sessions per week) with intake recommendations of the German, Austrian and Swiss Nutrition Societies (Deutsche, Österreichische und Schweizerische Gesellschaften für Ernährung, D-A-CH) for the general population. Lifestyle factors and supplement intake were examined via questionnaires; dietary habits and nutrient intake were determined based on 3-day dietary records. Results More than half of each group did not reach the recommended energy intake (OMN: 10.4, 8.70–12.1; LOV: 9.67, 8.55–10.8; VEG: 10.2, 9.12–11.3 MJ). Carbohydrate intake was slightly below the recommendations of > 50 EN% in OMN (46.7, 43.6–49.8 EN%), while LOV (49.4, 45.5–53.3 EN%) and VEG (55.2, 51.4–59.0 EN%) consumed adequate amounts (p = 0.003). The recommended protein intake of 0.8 g/kg body weight (D-A-CH) was exceeded in all three groups (OMN: 1.50, 1.27–1.66; LOV: 1.34, 1.09–1.56; VEG: 1.25; 1.07–1.42 g/kg BW; p = 0.047). Only VEG (26.3, 22.7–29.8 EN%) did not achieve the recommended fat intake of 30 EN%. The supply of micronutrients, such as vitamin D and cobalamin, was dependent on supplement intake. Additionally, female OMN and LOV achieved the recommended daily intake of 15 mg iron only after supplementation, while VEG consumed adequate amounts solely via food. Conclusion All three groups were sufficiently supplied with most nutrients despite the exceptions mentioned above. The VEG group even showed advantages in nutrient intake (e.g. carbohydrat

Intrauterine growth restriction (IUGR) refers to the situation where a fetus does not grow according to its genetic growth potential. One of the main causes of IUGR is uteroplacental vascular insufficiency. Under these circumstances of chronic oxygen and nutrient deprivation, the growth-restricted fetus often displays typical circulatory changes, which in part represent adaptations to the suboptimal intrauterine environment. These fetal adaptations aim to preserve oxygen and nutrient supply to vital organs such as the brain, the heart, and the adrenals. These prenatal circulatory adaptations are thought to lead to an altered development of the cardiovascular system and "program" the fetus for life long cardiovascular morbidities. In this review, we discuss the alterations to cardiovascular structure, function, and control that have been observed in growth-restricted fetuses, neonates, and infants following uteroplacental vascular insufficiency. We also discuss the current knowledge on early life surveillance and interventions to prevent progression into chronic disease.Copyright © 2016 International Pediatric Research Foundation, Inc.

Intrauterine growth restriction (IUGR) refers to the situation where a fetus does not grow according to its genetic growth potential. One of the main causes of IUGR is uteroplacental vascular insufficiency. Under these circumstances of chronic oxygen and nutrient deprivation, the growth-restricted fetus often displays typical circulatory changes, which in part represent adaptations to the suboptimal intrauterine environment. These fetal adaptations aim to preserve oxygen and nutrient supply to vital organs such as the brain, the heart, and the adrenals. These prenatal circulatory adaptations are thought to lead to an altered development of the cardiovascular system and "program" the fetus for life long cardiovascular morbidities. In this review, we discuss the alterations to cardiovascular structure, function, and control that have been observed in growth-restricted fetuses, neonates, and infants following uteroplacental vascular insufficiency. We also discuss the current knowledge on early life surveillance and interventions to prevent progression into chronic disease.Copyright © 2016 International Pediatric Research Foundation, Inc.

We investigated the influence of ocean mixing and nutrient supply dynamics on picoplankton community composition in the context of Margalef’s Mandala (Margalef 1978). Simultaneous measurements of microturbulence, nutrient concentration, and autotrophic and heterotrophic picoplankton properties, were collected during 3 cruises carried out in the northwestern Mediterranean Sea in March (F1), April/May (F2) and September (F3) 2009. The 3 cruises sampled different oceanographic conditions, starting with early stages of the late winter-early spring bloom, followed by the late stage of the bloom, and finally summer stratification. As a result of the variability in vertical diffusivity and the nitrate gradient across the nitracline, nitrate vertical fluxes were higher during F1 (23 ± 35 mmol m−2 d−1), compared to F2 (0.4 ± 0.2 mmol m−2 d−1) and F3 (0.09 ± 0.09 mmol m−2 d−1). Prochlorococcus abundance was low when nitrate supply was high, Synechococcus exhibited the highest abundances at intermediate levels of nitrate supply and highest irradiance during F2, and large and small picoeukaryotic groups increased their abundance under high nutrient supply in F1. No significant relationships between the abundance of high and low nucleic acid heterotrophic bacteria and nitrate supply were found. In agreement with Margalef’s model, our results show different responses of picophytoplankton groups to nitrate supply (probably reflecting differences in nutrient uptake abilities), and that the ratio of prokaryotic to picoeukaryotic photoautotrophic biomass decreases with increasing nitrate supply.

The Margalef´s mandala (1978) is a simplified bottom-up control model that explains how mixing and nutrient concentration determine the composition of marine phytoplankton communities. Due to the difficulties of measuring turbulence in the field, previous attempts to verify this model have applied different proxies for nutrient supply, and very often used interchangeably the terms mixing and stratification. Moreover, because the mandala was conceived before the discovery of smaller phytoplankton groups (picoplankton <2 µm), it describes only the succession of vegetative phases of microplankton. In order to test the applicability of the classical mandala to picoplankton groups, we used a multidisciplinary approach including specifically designed field observations supported by remote sensing, database analyses, and modeling and laboratory chemostat experiments. Simultaneous estimates of nitrate diffusive fluxes, derived from microturbulence observations, and picoplankton abundance collected in more than 200 stations, spanning widely different hydrographic regimes, showed that the contribution of eukaryotes to picoautotrophic biomass increases with nutrient supply, whereas that of picocyanobacteria shows the opposite trend. These findings were supported by laboratory and modeling chemostat experiments that reproduced the competitive dynamics between picoeukaryote sand picocyanobacteria as a function of changing nutrient supply. Our results indicate that nutrient supply controls the distribution of picoplankton functional groups in the ocean, further supporting the model proposed by Margalef.

We investigated the influence of ocean mixing and nutrient supply dynamics on picoplankton community composition in the context of Margalef's Mandala (Margalef 1978). Simultaneous measurements of microturbulence, nutrient concentration, and autotrophic and heterotrophic picoplankton properties, were collected during 3 cruises carried out in the northwestern Mediterranean Sea in March (F1), April/May (F2) and September (F3) 2009. The 3 cruises sampled different oceanographic conditions, starting with early stages of the late winter-early spring bloom, followed by the late stage of the bloom, and finally summer stratification. As a result of the variability in vertical diffusivity and the nitrate gradient across the nitracline, nitrate vertical fluxes were higher during F1 (23 ± 35 mmol m d), compared to F2 (0.4 ± 0.2 mmol m d) and F3 (0.09 ± 0.09 mmol m d). Prochlorococcus abundance was low when nitrate supply was high, Synechococcus exhibited the highest abundances at intermediate levels of nitrate supply and highest irradiance during F2, and large and small picoeukaryotic groups increased their abundance under high nutrient supply in F1. No significant relationships between the abundance of high and low nucleic acid heterotrophic bacteria and nitrate supply were found. In agreement with Margalef's model, our results show different responses of picophytoplankton groups to nitrate supply (probably reflecting differences in nutrient uptake abilities), and that the ratio of prokaryotic to picoeukaryotic photoautotrophic biomass decreases with increasing nitrate supply

We used hyperspectral imaging to study short-term effects of bioturbation by lugworms (Arenicola marina) on the surficial biomass of microphytobenthos (MPB) in permeable marine sediments. Within days to weeks after the addition of a lugworm to a homogenized and recomposed sediment, the average surficial MPB biomass and its spatial heterogeneity were, respectively, 150-250% and 280% higher than in sediments without lugworms. The surficial sediment area impacted by a single medium-sized lugworm (∼4 g wet weight) over this time-scale was at least 340 cm2. While sediment reworking was the primary cause of the increased spatial heterogeneity, experiments with lugworm-mimics together with modeling showed that bioadvective porewater transport from depth to the sediment surface, as induced by the lugworm ventilating its burrow, was the main cause of the increased surficial MPB biomass. Although direct measurements of nutrient fluxes are lacking, our present data show that enhanced advective supply of nutrients from deeper sediment layers induced by faunal ventilation is an important mechanism that fuels high primary productivity at the surface of permeable sediments even though these systems are generally characterized by low standing stocks of nutrients and organic material.

Limited nutrient diffusion in three-dimensional (3D) constructs is a major concern in tissue engineering. Therefore, monitoring nutrient availability and diffusion within a scaffold is an important asset. Since nutrients come in various forms, we have investigated the diffusion of the oxygen, luciferin and dextran molecules within tissue-engineered constructs using optical imaging technologies. First, oxygen availability and diffusion were investigated, using transgenic cell lines in which a hypoxia-responsive element drives expression of the green fluorescent protein gene. Using confocal imaging, we observed oxygen limitation, starting at around 200 ?m from the periphery in the context of agarose gel with 1 million CHO cells. Diffusion of luciferin was monitored real-time in agarose gels using a cell line in which the luciferase gene was driven by a constitutively active CMV promoter. Gel concentration affected the diffusion rate of luciferin. Furthermore, we assessed the diffusion rates of fluorescent dextran molecules of different molecular weights in biomaterials by fluorescence recovery after photobleaching (FRAP) and observed that diffusion depended on both molecular size and gel concentration. In conclusion, we have validated a set of efficient tools to investigate molecular diffusion of a range of molecules and to optimize biomaterials design in order to improve nutrient delivery.

Limited nutrient diffusion in three-dimensional (3D) constructs is a major concern in tissue engineering. Therefore, monitoring nutrient availability and diffusion within a scaffold is an important asset. Since nutrients come in various forms, we have investigated the diffusion of the oxygen, luciferin and dextran molecules within tissue-engineered constructs using optical imaging technologies. First, oxygen availability and diffusion were investigated, using transgenic cell lines in which a hypoxia-responsive element drives expression of the green fluorescent protein gene. Using confocal imaging, we observed oxygen limitation, starting at around 200 ?m from the periphery in the context of agarose gel with 1 million CHO cells. Diffusion of luciferin was monitored real-time in agarose gels using a cell line in which the luciferase gene was driven by a constitutively active CMV promoter. Gel concentration affected the diffusion rate of luciferin. Furthermore, we assessed the diffusion rates of fluorescent dextran molecules of different molecular weights in biomaterials by fluorescence recovery after photobleaching (FRAP) and observed that diffusion depended on both molecular size and gel concentration. In conclusion, we have validated a set of efficient tools to investigate molecular diffusion of a range of molecules and to optimize biomaterials design in order to improve nutrient delivery.

Rivers transport nutrients and suspended sediment matter (SSM) as well as fresh water from land to coastal regions, where the biological productivity is high. In the coastal area, the buoyancy of fresh water leads to the formation of horizontal anticyclonic gyres and vertical circulations, which affect the variation of biological production such as plankton blooms. However, the primary production caused by the 3-D dynamics have not been quantitatively discussed, and observations can hardly capture the daily temporal variations of phytoplankton blooms. We developed an ocean general circulation model including a simple ecosystem model, to investigate the 3-D and temporal changes in phytoplankton blooms caused by riverine input such as flooding. The distribution patterns of nutrients and phytoplankton differ significantly from that of fresh water. The phytoplankton maxima shift from the downstream (right-hand side of the river mouth) to the upstream regions (left-hand side of the river mouth). The shift that occurs is categorized by the different nitrate origins: (1) river-originated nitrate is dominant in the downstream region; (2) subsurface-originated nitrate is dominant in the upstream region, and is transported by upwelling associated with vertical circulation and horizontal anticyclonic gyre; and (3) regenerated nitrate is dominant in the upstream region. The total primary production in phytoplankton blooms is maintained not only by river-originated nitrate but also by subsurface-originated nitrate that is 1.5 times larger than the river-originated. Several case studies (e.g., including SSM) were conducted in this study.

Rivers transport nutrients and suspended sediment matter (SSM) as well as fresh water from land to coastal regions, where the biological productivity is high. In the coastal area, the buoyancy of fresh water leads to the formation of horizontal anticyclonic gyres and vertical circulations, which affect the variation of biological production such as plankton blooms. However, the primary production caused by the 3-D dynamics have not been quantitatively discussed, and observations can hardly capture the daily temporal variations of phytoplankton blooms. We developed an ocean general circulation model including a simple ecosystem model, to investigate the 3-D and temporal changes in phytoplankton blooms caused by riverine input such as flooding. The distribution patterns of nutrients and phytoplankton differ significantly from that of fresh water. The phytoplankton maxima shift from the downstream (right-hand side of the river mouth) to the upstream regions (left-hand side of the river mouth). The shift that occurs is categorized by the different nitrate origins: (1) river-originated nitrate is dominant in the downstream region; (2) subsurface-originated nitrate is dominant in the upstream region, and is transported by upwelling associated with vertical circulation and horizontal anticyclonic gyre; and (3) regenerated nitrate is dominant in the upstream region. The total primary production in phytoplankton blooms is maintained not only by river-originated nitrate but also by subsurface-originated nitrate that is 1.5 times larger than the river-originated. Several case studies (e.g., including SSM) were conducted in this study.

Rivers transport nutrients and suspended sediment matter (SSM) as well as fresh water from land to coastal regions, where the biological productivity is high. In the coastal area, the buoyancy of fresh water leads to the formation of horizontal anticyclonic gyres and vertical circulations, which affect the variation of biological production such as plankton blooms. However, the primary production caused by the 3-D dynamics have not been quantitatively discussed, and observations can hardly capture the daily temporal variations of phytoplankton blooms. We developed an ocean general circulation model including a simple ecosystem model, to investigate the 3-D and temporal changes in phytoplankton blooms caused by riverine input such as flooding. The distribution patterns of nutrients and phytoplankton differ significantly from that of fresh water. The phytoplankton maxima shift from the downstream (right-hand side of the river mouth) to the upstream regions (left-hand side of the river mouth). The shift that occurs is categorized by the different nitrate origins: (1) river-originated nitrate is dominant in the downstream region; (2) subsurface-originated nitrate is dominant in the upstream region, and is transported by upwelling associated with vertical circulation and horizontal anticyclonic gyre; and (3) regenerated nitrate is dominant in the upstream region. The total primary production in phytoplankton blooms is maintained not only by river-originated nitrate but also by subsurface-originated nitrate that is 1.5 times larger than the river-originated. Several case studies (e.g., including SSM) were conducted in this study.

Rehabilitation of mine tailings dams is often a challenge due to a lack of nutrients and a poor humus reservoir prevailing in tailings soils. This is especially true for establishing longer lived species such as trees. For these reasons the effects of different soil ameliorants (woodchips compost, vermicompost, mature sewage sludge), added to the root system of Karee (Searcia lancea) saplings were tested in pot trials. Those pots were filled with platinum and gold tailings substrate as well as red clay soil, respectively. For three months plants remained in a greenhouse and were subsequently moved to a test field outside. Throughout the test period regular chl a fluorescence measurements were taken and subjected to JIP-test quantifying changes in photosynthetic vitality status. Additionally, growth measurements and one-off leaf analysis were carried out. Test plants growing on mine tailings experienced an up to 35% higher average photosynthetic vitality (PIABS) and improved nutrient supply, when treated with mature sewage sludge. Consequently, sewage sludge treated plants showed a higher biomass build-up rate and an up to 55% higher diameter growth, compared to control. In summary the experiments present a low cost alternative for reforestation enterprises on platinum and gold tailings dams in South Africa.

Rehabilitation of mine tailings dams is often a challenge due to a lack of nutrients and a poor humus reservoir prevailing in tailings soils. This is especially true for establishing longer lived species such as trees. For these reasons the effects of different soil ameliorants (woodchips compost, vermicompost, mature sewage sludge), added to the root system of Karee (Searcia lancea) saplings were tested in pot trials. Those pots were filled with platinum and gold tailings substrate as well as red clay soil, respectively. For three months plants remained in a greenhouse and were subsequently moved to a test field outside. Throughout the test period regular chl a fluorescence measurements were taken and subjected to JIP-test quantifying changes in photosynthetic vitality status. Additionally, growth measurements and one-off leaf analysis were carried out. Test plants growing on mine tailings experienced an up to 35% higher average photosynthetic vitality (PIABS) and improved nutrient supply, when treated with mature sewage sludge. Consequently, sewage sludge treated plants showed a higher biomass build-up rate and an up to 55% higher diameter growth, compared to control. In summary the experiments present a low cost alternative for reforestation enterprises on platinum and gold tailings dams in South Africa.

It is commonly assumed that the nitrogen to phosphorus (N:P) ratio of a terrestrial plant reflects the relative availability of N and P in the soil in which the plant grows. Here, this was assessed for a tropical pioneer tree, Ficus insipida. Seedlings were grown in sand and irrigated with nutrient solutions containing N:P ratios ranging from <1 to >100. The experimental design further allowed investigation of physiological responses to N and P availability. Homeostatic control over N:P ratios was stronger in leaves than in stems or roots, suggesting that N:P ratios of stems and roots are more sensitive indicators of the relative availability of N and P at a site than N:P ratios of leaves. The leaf N:P ratio at which the largest plant dry mass and highest photosynthetic rates were achieved was ∼11, whereas the corresponding whole-plant N:P ratio was ∼6. Plant P concentration varied as a function of transpiration rate at constant nutrient solution P concentration, possibly due to transpiration-induced variation in the mass flow of P to root surfaces. The transpiration rate varied in response to nutrient solution N concentration, but not to nutrient solution P concentration, demonstrating nutritional control over transpiration by N but not P. Water-use efficiency varied as a function of N availability, but not as a function of P availability.

Establishment of nutrient management of citrus groves for high yield and superior crop quality is a need for efficient production. Limited phosphorus (P) availability of low fertility tropical soils in Brazil impairs citrus production since adequate P supply is important in the first years after field planting. Research has demonstrated that tree growth and fruit yield in response to P fertilization vary depending on rootstock varieties. Therefore, this study evaluated P uptake and redistribution by Pêra sweet orange on Rangpur lime or Cleopatra mandarin rootstocks initially grown in nutrient solution containing either deficient (0.005 mmol/L) or suficient(1.0 mmol/L) P levels. Each of these groups of plants was later half maintained in the deficient P whereas other half was changed to the suficient P solutions both labeled with 32P (14.8 MBq per 9.0 L pot). Plants were further grown for 50 days. Based on concentrations of P in plant parts derived from solution and P remobilized in plant, we observed that, despite variations on plant growth on different rootstocks, P taken up by those on Rangpur lime was superior confirming greater efficiency of nutrient uptake of this rootstock under a non mycorrhized condition. Estimates of P remobilized from plant reserve to young leaves suggested that the process was more marked for plants on Cleopatra mandarin irrespective to P treatments. These explained the fact that leaf visual symptoms of P deficiency are more frequent on trees on Cleopatra rootstock and presented the need to fine tune P fertilization recommendations.

The healing process for bone fractures is sensitive to mechanical stability and blood supply at the fracture site. Most currently available mechanobiological algorithms of bone healing are based solely on mechanical stimuli, while the explicit analysis of revascularization and its influences on the healing process have not been thoroughly investigated in the literature. In this paper, revascularization was described by two separate processes: angiogenesis and nutrition supply. The mathematical models for angiogenesis and nutrition supply have been proposed and integrated into an existing fuzzy algorithm of fracture healing. The computational algorithm of fracture healing, consisting of stress analysis, analyses of angiogenesis and nutrient supply, and tissue differentiation, has been tested on and compared with animal experimental results published previously. The simulation results showed that, for a small and medium-sized fracture gap, the nutrient supply is sufficient for bone healing, for a large fracture gap, non-union may be induced either by deficient nutrient supply or inadequate mechanical conditions. The comparisons with experimental results demonstrated that the improved computational algorithm is able to simulate a broad spectrum of fracture healing cases and to predict and explain delayed unions and non-union induced by large gap sizes and different mechanical conditions. The new algorithm will allow the simulation of more realistic clinical fracture healing cases with various fracture gaps and geometries and may be helpful to optimise implants and methods for fracture fixation.

Establishment of nutrient management of citrus groves for high yield and superior crop quality is a need for efficient production. Limited phosphorus (P) availability of low fertility tropical soils in Brazil impairs citrus production since adequate P supply is important in the first years after field planting. Research has demonstrated that tree growth and fruit yield in response to P fertilization vary depending on rootstock varieties. Therefore, this study evaluated P uptake and redistribution by Pêra sweet orange on Rangpur lime or Cleopatra mandarin rootstocks initially grown in nutrient solution containing either deficient (0.005 mmol/L) or suficient(1.0 mmol/L) P levels. Each of these groups of plants was later half maintained in the deficient P whereas other half was changed to the suficient P solutions both labeled with 32P (14.8 MBq per 9.0 L pot). Plants were further grown for 50 days. Based on concentrations of P in plant parts derived from solution and P remobilized in plant, we observed that, despite variations on plant growth on different rootstocks, P taken up by those on Rangpur lime was superior confirming greater efficiency of nutrient uptake of this rootstock under a non mycorrhized condition. Estimates of P remobilized from plant reserve to young leaves suggested that the process was more marked for plants on Cleopatra mandarin irrespective to P treatments. These explained the fact that leaf visual symptoms of P deficiency are more frequent on trees on Cleopatra rootstock and presented the need to fine tune P fertilization recommendations.

Growing evidence of inorganic nutrient limitation on oceanic bacteria suggests a global dependence of bacterial activity and production on rates of nutrient supply. The present study examined whether surface bacterial abundance is significantly related to water column stability, and whether bacterial activity and growth rate are related to the rate of diffusive supply of inorganic nutrients to the mixed layer in the Central Atlantic during 2 meridional cruises. The 2 cruises were run under very different oceanic conditions, with relatively low values of bacterial activity in spring 1995 and relatively higher values in fall 1995. We obtained depth-resolved data in the second cruise and found that the integrated value of bacterial production was also related to the rate of nutrient supply, while integrated particulate primary production and chlorophyll concentration were not. There was also no relationship between particulate primary production and bacterial production. The relationship between nutrient supply and integrated bacterial production was tested with data from a mesocosm experiment showing a good fit to the pattern obtained in the Atlantic. Average bacterial production was ~21% of primary production in the Central Atlantic, with values ranging between 5 and 100%, and higher values in the tropical areas. The demonstration of a direct relationship between nutrient supply and bacterial activity helps to explain a relatively large bacterial biomass as compared to phytoplankton biomass, a low bacterial growth efficiency, and a high bacterial carbon demand relative to contemporaneous primary production often measured in the open ocean, as well as the accumulation of dissolved organic carbon (DOC) observed in nutrient-limited oligotrophic seas

The objetive of this work was to study if the addition of nutrients to the irrigation water modified ‘Manzanilla de Sevilla’ olive pulp and pit growth. The experiment was carried out during the 2003 fruitgrowth period in an irrigated orchard near Seville, southern Spain. Fruit samples were taken in July and September, at 12 and 21 weeks after full bloom(AFB) respectively, in trees irrigated with (T1) or without (T0) the addition of nutrients (N–P–K). The nutrient availability of T1 fruits increased the fruit fresh and dry weight, longitudinal and equatorial diameters, and the pulp-to-pit ratio, characteristics particularly appreciated for table olives. The balance of growth between the fruit mesocarp (pulp) and endocarp (pit) was modified because those two tissues were affected differently. Mesocarp fresh weight was significantly higher at both 12 and 21 weeks AFB in the fertilized treatment, as was mesocarp dry weight at 12 weeks AFB. Neither the endocarp fresh and dry weight nor shape (the ratio of the equatorial and longitudinal diameters) was altered at either of the two studied dates. These results emphasize the importance of an appropriate fertilization management in irrigated olive orchards, particularly for table olives, and also confirm the olive endocarp as a strong sink tissue that competes with the mesocarp during early development.

Ecologically important macroalgae with large thalli and complex structures are threatened worldwide due to anthropogenic activities such as pollution. In the northern Baltic Sea the salinity is very low; the only large algae producing complex structural habitats found there are the fucoid species Fucus radicans and F. vesiculosus. This thesis investigates the importance of these two species for the diversity of the faunal communities living in algal vegetation. The trophic effects of high nutrient supply and grazers on the survival, facilitation, and diversity of F. vesiculosus were also studied. Fucoid vegetation generally harboured a higher biomass and different composition of associated fauna m–2 than did vegetation types without fucoids. Through the occurrence of Pilayella littoralis, high nutrient supply had indirect negative effects on early stages of F. vesiculosus survival; these effects were exerted by both the presence of and exudates from P. littoralis. Another indirect effect of high nutrient supply was higher epiphytic load, but this did not have any impact on the growth of F. vesiculosus. Instead, grazers had a positive effect by reducing the biomass of fouling epiphytes, though the identity of the grazer species was crucial in this. Furthermore, when investigating the effect of grazers on the epiphyte biomass it became evident that only the presence of two species with complementary feeding habits effectively prevented overgrowth. The biodiversity of the epiphytes was affected by both nutrient level and grazing pressure, which indicates that the effect of grazers on algal diversity depends on resource supply. This thesis demonstrates that fucoids are important for hard bottom fauna, and that F. vesiculosus (particularly at early life stages, and to a lesser extent as adults) is sensitive to high nutrient loads. Furthermore, it was evident that specific species of grazers, i.e., Theodoxus fluviatilis, were able to facilitate the growth of this alga.

Personalised, genotype-based nutrition is a concept that links genotyping with specific nutritional advice in order to improve the prevention of nutrition-associated, chronic diseases. This review describes the current scientific basis of the concept and discusses its problems. There is convincing evidence that variant genes may indeed determine the biological response to nutrients. The effects of single-gene variants on risk or risk factor levels of a complex disease are, however, usually small and sometimes inconsistent. Thus, information on the effects of combinations of relevant gene variants appears to be required in order to improve the predictive precision of the genetic information. Furthermore, very few associations between genotype and response have been tested for causality in human intervention studies, and little is known about potential adverse effects of a genotype-derived intervention. These issues need to be addressed before genotyping can become an acceptable method to guide nutritional recommendations. © The Authors 2007.

The Northern Areas of Pakistan form a mountainous, semi-arid region in which subsistence mixed farming is the predominant economic activity for the majority of the population, which numbers around 1 million. Following a period of relative isolation, construction of the Karakoram Highway and the ensuing development activity have been catalysts for rapid infrastructural and social change over the last two decades. In the study reported here, feed resources for the livestock enterprise, which is largely made up of cattle, goats and sheep, were studied in detail over the course of a single winter feeding season. Productive outputs including liveweight change, milk production and reproductive performance were also quantified over a full year. The aim of the study was to provide a quantitative description of the system and to assess the extent to which proximity to a major highway influenced livestock husbandary. Six villages across the region were selected for study as part of a 2 × 3 factorial design with one village per cell of the study design. Factors consisted of two geographical transects and three agro-ecological zones. Transects were the Karakoram Highway (KKH) transect which enjoyed relatively good transport infrastructure and the Gilgit Ghizer Region (GGR) transect where infrastructure was more limited. Agro-ecological zones were the single, transitional and double cropping zones. One village per transect from each of the three main agro-ecological zones was chosen for study with 6–7 households within each village studied. Results showed that feed resources per household did not vary significantly according to transect or zone but cattle numbers per household were higher in the GGR transect than in the KKH transect indicating a heavier reliance on subsistence livestock production in this transect. Live weight and body condition of livestock in the Northern Areas changed markedly over the annual cycle. Losses of live weight were in the order of 10% over winter w

Author Posting. © National Research Council Canada, 2005. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 62 (2005): 1905-1919, doi:10.1139/F05-100., We predicted that substratum freezing and instability are major determinants of the variability of stream community structure in Arctic Alaska. Their effects were conceptualized as a two-dimensional habitat template that was assessed using a natural experiment based on five stream types (mountain-spring, tundra-spring, tundra, mountain, glacier). Detrended correspondence analysis (DCA) indicated distinct macroinvertebrate assemblages for each stream type. The contribution of functional feeding groups to assemblage biomass varied systematically among stream types, indicating that structure and function are linked. Assemblage position within a DCA biplot was used to assess factors controlling its structure. Springs separated from other stream types along a gradient of nutrient concentration and freezing probability. Glacier and mountain streams separated from springs and tundra streams along a gradient of substratum instability and freezing probability. Owing to differences in sources of discharge to streams, the effects of nutrients and substratum stability could not be separated from freezing. Although many factors likely contribute to the variability of Arctic stream communities, the major determinants may be conceptualized as a template structured by gradients in (i) nutrient supply and substratum freezing and (ii) substratum instability and substratum freezing. This template provides a basis for predicting the response of Arctic stream communities to climate change., Funding was provided by grants from the National Science Foundation (NSF DEB-9810222 and NSF OPP-9911278).

Author Posting. © National Research Council Canada, 2005. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 62 (2005): 1905-1919, doi:10.1139/F05-100., We predicted that substratum freezing and instability are major determinants of the variability of stream community structure in Arctic Alaska. Their effects were conceptualized as a two-dimensional habitat template that was assessed using a natural experiment based on five stream types (mountain-spring, tundra-spring, tundra, mountain, glacier). Detrended correspondence analysis (DCA) indicated distinct macroinvertebrate assemblages for each stream type. The contribution of functional feeding groups to assemblage biomass varied systematically among stream types, indicating that structure and function are linked. Assemblage position within a DCA biplot was used to assess factors controlling its structure. Springs separated from other stream types along a gradient of nutrient concentration and freezing probability. Glacier and mountain streams separated from springs and tundra streams along a gradient of substratum instability and freezing probability. Owing to differences in sources of discharge to streams, the effects of nutrients and substratum stability could not be separated from freezing. Although many factors likely contribute to the variability of Arctic stream communities, the major determinants may be conceptualized as a template structured by gradients in (i) nutrient supply and substratum freezing and (ii) substratum instability and substratum freezing. This template provides a basis for predicting the response of Arctic stream communities to climate change., Funding was provided by grants from the National Science Foundation (NSF DEB-9810222 and NSF OPP-9911278).

A 5-year study of the reforestation of a semiarid Mediterranean ecosystem with Pinus halepensis is presented. Reforestation of Mediterranean semiarid ecosystems is challenging as a result of harsh environmental conditions and historical human exploitation leading to degradation. New techniques have to be developed in order to increase survivorship and growth that integrates nursery and field treatments. A total of 60 treatments resulting from 12 site × 5 plant preparation techniques were tested. Plant preparation consists of mycorrhizing in nursery, extra fertilizing in nursery, planting in containers in the nursery, planting in the field with a polypropylene tube, and control plants (bred in plastic bags). Soil preparation consists of hole, subsoiling without amendment, subsoiling with composted organic amendment added in the surface or in the furrow of plantation and subsoiling with fresh organic amendment added in the surface or in the furrow of plantation. Each one of these treatments was tested with a hydrophilic acrylic copolymer and without it. Survivorship was very high (0.91) given the prevailing environmental conditions. Subsoiling promoted higher survival than holes, and plants bred in containers had lower levels of survivorship than control ones. Protecting seedlings with polypropylene tubes had no effect on survivorship. The most effective treatment for promoting growth was organic amendment, the effect of which increased until the fourth year. Protection with tubes was very effective in increasing height, although only in the short-term. Subsoiling also promoted faster growth than holes, although the effect was less noticeable after 3 years and was, in any case, less effective than organic amendment. Other treatments promoting faster growth were the use of fresh organic waste as opposed to composted waste and its incorporation in the plantation furrow rather than as a layer on the surface. The addition of hydrophilic acrylic copolymer reduced growth du

Upland rice (Oryza sativa L.) is mainly grown in Asia, Africa and Latin America. Yield potential of upland rice is quite low and invariably this crop is subjected to many environmental stresses. Further, when upland rice is grown in monoculture for more than two to three years on the same land, allelopathy or autotoxicity is frequently reported. Allelopathy involves complex plant and plant chemical interactions. The level of phytotoxicity of allelochemicals is influenced by abiotic and biotic soil factors. Adopting suitable management strategies in crop rotation can reduce or eliminate allelochemicals phytotoxicity. Rice yields can be improved by growing rice in rotation with other crop species. Allelochemicals of rice can be used for control of weeds in this crop as well as other crops that are grown in rotation with rice. This review highlights that present knowledge of allelopathy in upland rice is inadequate and fragmentary, and therefore, more controlled and field studies are needed to understand and to reduce the detrimental effects of allelopathy in the upland rice production.