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Mansilla A.,University of Magallanes | Mansilla A.,Institute of Ecology and Biodiversity | Avila M.,Arturo Prat University
Brazilian Journal of Pharmacognosy | Year: 2011

The exploitation of seaweeds in Chile has been carried out for more than 60 years. More recently, seaweeds have been used for the production of alginate, agar and carrageenan, agricultural fertilizers and industrial aquaculture (feed for abalone and sea urchins), increasing the added value of this natural resource. In the Magellan Region (56°S), the giant kelp Macrocystis pyrifera (L.) C. Agardh presents the most extensive kelp forest, reaching a biomass of approximately 12 kg.m-2. Recent studies have shown potential benefits from adding M. pyriferaderived flour to salmonid feed. Research is currently underway to evaluate the use of brown algae-derived products for marine aquaculture feed of Oncorhynchus mykiss in tanks. There was no apparent adverse effect on the evaluated parameters that can be attributed to the incorporation of M. pyrifera meal in the diets fed to salmonids. Even when the control diet had numerically the best performance in zootechnical terms, the analysis of variance of all parameters evaluated showed no significant differences with regard to diets containing M. pyrifera meal. These results demonstrated that seaweed meal has important benefits for animal health and nutrition that could be applied or tested in other marine organisms of commercial importance.

Rodriguez-Echeverria S.,University of Coimbra | Armas C.,CSIC - Estacion Experimental De Zonas Aridas | Armas C.,Institute of Ecology and Biodiversity | Armas C.,University of La Serena | And 4 more authors.
Journal of Ecology | Year: 2013

Plant-plant facilitation is an important driver of plant diversity, which in turn maintains ecosystem multifunctionality and can buffer some negative effects of climate change. Facilitation is classically attributed to the amelioration of environmental extremes and resource availability. Integrating below-ground biota into the positive plant interactions framework should provide a more realistic understanding of this process, enabling us to gain insights into the dynamics of below-above-ground communities. We tested the effect of below-ground biota on the performance of a plant community and of individual species using soil extracts from the understorey of a benefactor plant species and adjacent open spaces. Soil bacteria from extracts and experimental microcosms were analysed using pyrosequencing. Soil biota had a significant effect on the abundance, growth, functional traits and reproductive output of beneficiary plant species through processes that are independent of the direct influence of the benefactor species. Different soil bacterial communities were associated with the benefactor species, the individual beneficiary plant species and the plant community, revealing complex below-above-ground links between plants and soil microbiota. Synthesis. The below-ground biota cultivated by benefactor plant species play a fundamental role in positive interactions between plant species contributing to the preservation of diversity and the evolution of plant communities. © 2013 British Ecological Society.

Navarro N.P.,University of Magallanes | Navarro N.P.,University of Sao Paulo | Mansilla A.,University of Magallanes | Mansilla A.,Institute of Ecology and Biodiversity | Plastino E.M.,University of Sao Paulo
Journal of Applied Phycology | Year: 2010

The effects of UVB radiation on the different developmental stages of the carrageenan-producing red alga Iridaea cordata were evaluated considering: (1) carpospore and discoid germling mortality; (2) growth rates and morphology of young tetrasporophytes; and (3) growth rates and pigment content of field-collected plant fragments. Unialgal cultures were submitted to 0.17, 0.5, or 0.83W m-2 of UVB radiation for 3h per day. The general culture conditions were as follows: 12h light/12h dark cycles; irradiance of 55 μmol photon per square meter per second; temperature of 9 ± 1°C; and seawater enriched with Provasoli solution. All UVB irradiation treatments were harmful to carpospores (0.17 Wm-2 = 40.9 ± 6.9%, 0.5 Wm-2 = 59.8 ± 13.4%, 0.83 Wm-2 = 40 ± 17.4% mortality in 3days). Even though the mortality of all discoid germlings exposed to UVB radiation was unchanged when compared to the control, those germlings exposed to 0.5 and 0.83W m-2 treatments became paler and had smaller diameters than those cultivated under control treatment. Decreases in growth rates were observed in young tetrasporophytes, mainly in 0.5 and 0.83W m-2 treatments. Similar effects were only observed in fragments of adult plants cultivated at 0.83W m-2. Additionally, UVB radiation caused morphological changes in fragments of adult plants in the first week, while the young individuals only displayed this pattern during the third week. The verified morphological alterations in I. cordata could be interpreted as a defense against UVB by reducing the area exposed to radiation. However, a high level of radiation appears to produce irreparable damage, especially under long-term exposure. Our results suggest that the sensitivity to ultraviolet radiation decreases with increased algal age and that the various developmental stages have different responses when exposed to the same doses of UVB radiation. © 2009 Springer Science+Business Media B.V.

Driscoll D.A.,National Environmental Research Program Environmental Decisions Group | Driscoll D.A.,Australian National University | Catford J.A.,National Environmental Research Program Environmental Decisions Group | Catford J.A.,Australian National University | And 13 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

Agricultural intensification is critical to meet global food demand, but intensification threatens native species and degrades ecosystems. Sustainable intensification (SI) is heralded as a new approach for enabling growth in agriculture while minimizing environmental impacts. However, the SI literature has overlooked a major environmental risk. Using data from eight countries on six continents, we show that few governments regulate conventionally bred pasture taxa to limit threats to natural areas, even though most agribusinesses promote taxa with substantial weed risk. New pasture taxa (including species, subspecies, varieties, cultivars, and plant-endophyte combinations) are bred with characteristics typical of invasive species and environmental weeds. By introducing novel genetic and endophyte variation, pasture taxa are imbued with additional capacity for invasion and environmental impact. New strategies to prevent future problems are urgently needed. We highlight opportunities for researchers, agribusiness, and consumers to reduce environmental risks associated with new pasture taxa. We also emphasize four main approaches that governments could consider as they build new policies to limit weed risks, including (i) national lists of taxa that are prohibited based on environmental risk; (ii) a weed risk assessment for all new taxa; (iii) a program to rapidly detect and control new taxa that invade natural areas; and (iv) the polluter-pays principle, so that if a taxon becomes an environmental weed, industry pays for its management. There is mounting pressure to increase livestock production. With foresight and planning, growth in agriculture can be achieved sustainably provided that the scope of SI expands to encompass environmental weed risks.

Astorga-Espana M.S.,University of Magallanes | Mansilla A.,University of Magallanes | Mansilla A.,Institute of Ecology and Biodiversity
Journal of Applied Phycology | Year: 2013

In order to promote the use of sub-Antarctic macroalgae as food, four species of marine macroalgae: Macrocystis pyrifera, Durvillaea antarctica, Pyropia columbina, and Callophyllis variegata were studied for their nutritional value. They were collected monthly between October and December 2012 throughout the Strait of Magallanes, sub-Antarctic Chile. The chemical composition, including carbohydrates, proteins, lipids, and vitamins A and C, and the macronutrient, mineral, and fatty acid content were examined. Ash (15.1-34.1 %) and soluble fiber (26.5 to 40.3 %) were the most abundant in these species. Presence of protein was moderate (8.2-25.0 %), with red alga (C. variegata) having the highest value on dry weight (dw). All algal species had lipid contents of less than 5 % dw. Maximum carbohydrate content was observed in P. columbina (9.5 % dw). Potassium was the most abundant essential element found in M. pyrifera (8.51 % dw), while P. columbina was found to be richest in iron (305.5 ± 5.5 μg g-1 dw) and C. variegata showed the highest contents of Cu (17.4 ± 0.7 μg g-1 dw). The most abundant saturated fatty acids were palmitic (C16:0) and myristic acid (C14:0), with values ranging from 4.33 to 9.22 %. The most abundant monounsaturated fatty acid was oleic acid (C18:1ω9). The highest levels of polyunsaturated fatty acid were observed for arachidonic (20:4ω6) and eicosapentaenoic acid (C20:5ω3) or EPA. © 2013 Springer Science+Business Media Dordrecht.

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