UCN-CEAZA
Morphological, ultrastructural, and genetic characterization of coalescence in the intertidal and shallow subtidal kelps Lessonia spicata and L. berteroana (Laminariales, Heterokontophyta).
González, A., Borras-Chavez, R., Beltrán, J., Flores, V., Vásquez, J., & Santelices, B.
Coalescing macroalgae may fuse with conspecifics, forming genetically heterogeneous entities known as chimera. This process has been shown in taxa from roughly half the red algal orders and in the Codium species, a green alga. Field observations indicate that common and dominant kelps along central Chile exhibit a fused holdfast. We evaluated whether such fusions are true coalescence processes in Lessonia spicata and Lessonia berteroana. To this end, we characterized the ultrastructural event involved in holdfast fusion in the laboratory. Additionally, coalescence in natural populations was quantified by measuring the frequency of individuals with genetically heterogenic stipes within the same holdfast. Results indicate that coalescence appears as a frequent process in laboratory, mostly restricted to intraspecific fusions. During fusion, the meristodermatic cells located in the contact area modify their morphology and reduce the number of plastids, mitochondria, and cell inclusions. The cell wall becomes much thinner and develops plasmodesmata, enhancing communication with equivalent cells of the other coalescencing individual. Stipe genotyping indicates that there is a widespread occurrence of chimerism in both species and genetic heterogeneity is increasing directly with the increasing number of stipes. The combination of results suggests that kelp frequently coalesce in the field, and the histological response observed approaches that of red algae. Since kelps are part of the dominant vegetation in low intertidal and shallow subtidal beds, the adaptive values of coalescence in these species should be evaluated. It is concluded that coalescence and chimerism are evolutionary convergent processes, occurring in all three major groups of seaweeds.
Año: 2014
Palabras claves: Coalescence, Chimerism, Kelps, Lessonia, Microsatellites, Heterokontophyta.
Referencia APA: González, A., Borras-Chavez, R., Beltrán, J., Flores, V., Vásquez, J., & Santelices, B. (2014). Morphological, ultrastructural, and genetic characterization of coalescence in the intertidal and shallow subtidal kelps Lessonia spicata and L. berteroana (Laminariales, Heterokontophyta). J Appl Phycol, 26(2), 1107-1113.
Mass die-off of the cold-water coral Desmophyllum dianthus in the Chilean Patagonian fjord region.
Försterra, G., Häussermann, V., Laudien, J., Jantzen, C., Sellanes, J., & Muñoz, P.
In fjords and channels of the Chilean Patagonia, the solitary cold-water coral Desmophyllum dianthus (Esper, 1794) can be found in depths as shallow as 7 m as part of a deep-water emerging benthic community. In the Comau Fjord, one of three Chilean fjords where this species is forming large banks with multiple branched pseudo colonies on the steep rock walls, shallow water coral communities have been monitored for more than a decade. In 2012, a mass die-off was observed along 8.4 km of coast line and at least down to 70 m depth. Only specimens of D. dianthus were affected while other organisms, including two more scleractinian species, were not visibly damaged. The event coincides with exceptionally high efflux of methane and sulfide enriched water from cold vents in the rock walls at this site. Due to strongly increased salmon farming activity in the last decade, algae blooms have increased in frequency and intensity as a result of elevated primary production. We hypothesize and provide evidence that either harmful substances from the cold vents or hypoxia following an exceptionally strong algae bloom—or the synergistic effects of both—might have caused the mass mortality.
Año: 2014
Palabras claves:
Referencia APA: Försterra, G., Häussermann, V., Laudien, J., Jantzen, C., Sellanes, J., & Muñoz, P. (2014). Mass die-off of the cold-water coral Desmophyllum dianthus in the Chilean Patagonian fjord region. BMS, 90(3), 895-899.
Economic valuation of kelp forests in northern Chile: values of goods and services of the ecosystem.
Vásquez, J., Zuñiga, S., Tala, F., Piaget, N., Rodríguez, D., & Vega, J.
Kelp beds, besides being one of the most important benthic resources in northern Chile, provide a variety of environmental goods and services. In order to evaluate economically the wild kelp populations in northern Chile (26° to 32° S) more than simply their commercial value as a source of raw materials for alginate extraction, we used several economic indicators to holistically assess the value of a group of brown seaweeds of economic importance, Lessonia spp. and Macrocystis pyrifera: (1) market value of biomass as a source of raw material for extraction of alginic acid, (2) market value of associated species of economic importance, (3) value as a source of scientific information, (4) value as a climate buffer (CO2 capture and release of O2), (5) value of associated biodiversity (non-commercial species), (6) value as cultural heritage and (7) value as a reservoir of biodiversity. Existence values of kelp beds which estimate the willingness of citizens to pay and work without payment to preserve the ecosystem were calculated using the contingent valuation technique. The results indicate that kelp beds in northern Chile have a total value of US $540 million. Of this total, kelp fishery accounts for 75 % and associated-species fisheries account for 15 %. In this context, the economic value of Chilean kelp beds is mainly associated with the industry of alginate extraction. By contrast, existence value as a source of scientific information or environmental buffer for CO2 capture or O2 production represents only 9 % of the total value, representing a very low relative importance to society. The economic valuation of coastal resources and marine ecosystems is a complementary tool for decision making and implementation of public policies related to the conservation and sustainable exploitation of renewable resources and their ecosystems.
Año: 2014
Palabras claves: Kelp fishery, Phaeophyta, Administrative policies, Ecosystem goods and services, Conservation, Economic value.
Referencia APA: Vásquez, J., Zuñiga, S., Tala, F., Piaget, N., Rodríguez, D., & Vega, J. (2014). Economic valuation of kelp forests in northern Chile: values of goods and services of the ecosystem. J Appl Phycol, 26(2), 1081-1088.
Geochemistry of reduced fluids from shallow cold vents hosting chemosynthetic communities (Comau Fjord, Chilean Patagonia, ∼42°S).
Muñoz, P., Sellanes, J., Villalobos, K., Zapata-Hernández, G., Mayr, C., & Araya, K.
Reduced fluids from shallow-marine vents sustain chemosynthetic bacterial mats located at the base of the volcano Barranco Colorado in Comau Fjord (X-Huinay; 42°23.279′S, 72°27.635′W). We characterized the chemical environment in which these bacteria thrive. To this end, we analyzed CH4, ∑H2S, O2, DIC, and stable isotopes (δ13C, δ2H and δ18O) and compared them with readings taken at a control station (which lacks evidence of fluid venting and mat-forming bacteria). In addition, CTD measurements, chlorophyll-a, and nutrient analyses were performed. At depths of approximately 5–7 m, the water column exhibited a pycnocline that formed under the influence of fresh water discharges, especially during the summer season, which also affected the surface temperature. Bacterial mats and elemental sulfur flocs were observed in the vicinity of the vents (X-Huinay station), and higher concentrations of reduced compounds (CH4 and ∑H2S) were found in the vent fluids, in particular at a depth of 36 m. No significant differences in the temperatures of vent and ambient waters were detected. The bottom water close to the vents possessed notably low concentrations of reduced compounds, indicating a rapid and large-quantity dilution of the chemicals from vents. The surface water featured light isotopic values of δ2H and 18O due to the freshwater input from melting ice and precipitation. A linear mixing trend was observed between the freshwater (negative isotopic values) and the fjord bottom water (positive values) that was not influenced by vent fluid. This trend suggests that the venting water corresponds to the mixing among local meteoric water, spring water, and seawater. This result is relevant to understanding how freshwater and meteoric water influence the chemical composition of seawater and how this mixing could impact the marine biota in the vicinities of the vents.
Año: 2014
Palabras claves:
Referencia APA: Muñoz, P., Sellanes, J., Villalobos, K., Zapata-Hernández, G., Mayr, C., & Araya, K. (2014). Geochemistry of reduced fluids from shallow cold vents hosting chemosynthetic communities (Comau Fjord, Chilean Patagonia, ∼42°S). Progress In Oceanography, 129, 159-169.
Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus ) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny.
Baeza, J., Bauer, R., Okuno, J., & Thiel, M.
The Rhynchocinetidae (‘hinge-beak’ shrimps) is a family of marine caridean decapods with considerable variation in sexual dimorphism, male weaponry, mating tactics, and sexual systems. Thus, this group is an excellent model with which to analyse the evolution of these important characteristics, which are of interest not only in shrimps specifically but also in animal taxa in general. Yet, there exists no phylogenetic hypothesis, either molecular or morphological, for this taxon against which to test either the evolution of behavioural traits within the Rhynchocinetidae or its genealogical relationships with other caridean taxa. In this study, we tested (1) hypotheses on the phylogenetic relationships of rhynchocinetid shrimps, and (2) the efficacy of different (one-, two-, and three-phase) methods to generate a reliable phylogeny. Total genomic DNA was extracted from tissue samples taken from 17 species of Rhynchocinetidae and five other species currently or previously assigned to the same superfamily (Nematocarcinoidea); six species from other superfamilies were used as outgroups. Sequences from two nuclear genes (H3 and Enolase) and one mitochondrial gene (12S) were used to construct phylogenies. One-phase phylogenetic analyses (SATé-II) and classical two- and three-phase phylogenetic analyses were employed, using both maximum likelihood and Bayesian inference methods. Both a two-gene data set (H3 and Enolase) and a three-gene data set (H3, Enolase, 12S) were utilized to explore the relationships amongst the targeted species. These analyses showed that the superfamily Nematocarcinoidea, as currently accepted, is polyphyletic. Furthermore, the two major clades recognized by the SATé-II analysis are clearly concordant with the genera Rhynchocinetes and Cinetorhynchus, which are currently recognized in the morphological-based classification (implicit phylogeny) as composing the family Rhynchocinetidae. The SATé-II method is considered superior to the other phylogenetic analyses employed, which failed to recognize these two major clades. Studies using more genes and a more complete species data set are needed to test yet unresolved inter- and intrafamilial systematic and evolutionary questions about this remarkable clade of caridean shrimps. © 2014 The Linnean Society of London
Año: 2014
Palabras claves: Bayesian hypothesis testing; Crustacea; SATé-II.
Referencia APA: Baeza, J., Bauer, R., Okuno, J., & Thiel, M. (2014). Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny. Zool J Linn Soc, 172(2), 426-450.
Major consequences of minor damage: impacts of small grazers on fast-growing kelps.
Poore, A., Gutow, L., F. Pantoja, J., Tala, F., Jofré Madariaga, D., & Thiel, M.
Damage by small herbivores can have disproportionately large effects on the fitness of individual plants if damage is concentrated on valuable tissues or on select individuals within a population. In marine systems, the impact of tissue loss on the growth rates of habitat-forming algae is poorly understood. We quantified the grazing damage by an isopod Amphoroidea typa on two species of large kelps, Lessonia spicata and Macrocystis pyrifera, in temperate Chile to test whether non-lethal grazing damage could reduce kelp growth rates and photosynthetic efficiency. For L. spicata, grazing damage was widespread in the field, unevenly distributed on several spatial scales (among individuals and among tissue types) and negatively correlated with blade growth rates. In field experiments, feeding by A. typa reduced the concentration of photosynthetic pigments and led to large reductions (~80 %) in blade growth rates despite limited loss of kelp biomass (0.5 % per day). For M. pyrifera, rates of damage in the field were lower and high densities of grazers were unable to reduce growth rates in field experiments. These results demonstrate that even low per capita grazing rates can result in large reductions in the growth of a kelp, due the spatial clustering of herbivores in the field and the selective removal of photosynthetically active tissues. The impacts of small herbivores on plant performance are thus not easily predicted from consumption rates or abundance in the field, and vary with plant species due to variation in their ability to compensate for damage.
Año: 2014
Palabras claves: Grazing, Herbivory, Isopods, Lessonia, Mesograzers, Macroalgae, Macrocystis, Plant–herbivore interactions.
Referencia APA: Poore, A., Gutow, L., F. Pantoja, J., Tala, F., Jofré Madariaga, D., & Thiel, M. (2014). Major consequences of minor damage: impacts of small grazers on fast-growing kelps. Oecologia, 174(3), 789-801.
Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea.
Eriksen, M., Lebreton, L., Carson, H., Thiel, M., Moore, C., & Borerro, J. et al.
Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N = 680) and visual survey transects of large plastic debris (N = 891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.
Año: 2014
Palabras claves: Oceans, Density, Particle size, Pollution, Southern Hemisphere, Indian Ocean, Marine conservation, Mediterranean Sea.
Referencia APA: Eriksen, M., Lebreton, L., Carson, H., Thiel, M., Moore, C., & Borerro, J. et al. (2014). Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea. Plos ONE, 9(12), e111913.
Succession in intertidal mussel bed assemblages on different shores: species mobility matters.
Valdivia, N., Buschbaum, C., & Thiel, M.
Biogenic substrata such as epibenthic mussel aggregations are common in coastal regions worldwide and harbour diverse assemblages of sessile and mobile species. However, colonisation patterns on biogenic substrata are still not well understood. We tested whether succession develops as a linear sequence of temporal changes in the species richness and community structure of sessile and mobile assemblages associated with intertidal mussel beds of sedimentary and rocky shores in Germany and Chile, respectively. Because of their broad differences, these study sites were analysed separately to examine whether similar successional patterns occur under differing environmental conditions and species pools. At each study site, we conducted an experiment that separates the effects of successional age (deployment duration) and the time when settlement substrata are deployed (deployment timing). Colonisation dynamics differed between timings and between sessile and mobile species. In addition, timing effects were stronger at the sedimentary than at the rocky study site. For sessile organisms, for example, species richness increased steadily with successional age at both study sites, but at the sedimentary site, the magnitude of this increase varied between the different months of deployment. For mobile organisms, a high proportion of the total species pool colonised the settlement substrata within the first month of deployment at both sites. After this initial colonization peak, mobile species richness showed a minor but significant increase with successional age at both sites. We suggest that species dispersal ability at the local scale (mobility) mediates the response of species-rich assemblages to natural and anthropogenic disturbances.
Año: 2014
Palabras claves: Context-dependency, Determinism, Facilitation, Hard-bottom, Soft-bottom, Stochastic, Succession.
Referencia APA: Valdivia, N., Buschbaum, C., & Thiel, M. (2014). Succession in intertidal mussel bed assemblages on different shores: species mobility matters. Marine Ecology Progress Series, 497, 131-142
Phylogeographic Structure in Benthic Marine Invertebrates of the Southeast Pacific Coast of Chile with Differing Dispersal Potential.
Haye, P., Segovia, N., Muñoz-Herrera, N., Gálvez, F., Martínez, A., & Meynard, A. et al.
The role of dispersal potential on phylogeographic structure, evidenced by the degree of genetic structure and the presence of coincident genetic and biogeographic breaks, was evaluated in a macrogeographic comparative approach along the north-central coast of Chile, across the biogeographic transition zone at 30°S. Using 2,217 partial sequences of the mitochondrial Cytochrome Oxidase I gene of eight benthic invertebrate species along ca. 2,600 km of coast, we contrasted dispersal potential with genetic structure and determined the concordance between genetic divergence between biogeographic regions and the biogeographic transition zone at 30°S. Genetic diversity and differentiation highly differed between species with high and low dispersal potential. Dispersal potential, sometimes together with biogeographic region, was the factor that best explained the genetic structure of the eight species. The three low dispersal species, and one species assigned to the high dispersal category, had a phylogeographic discontinuity coincident with the biogeographic transition zone at 30°S. Furthermore, coalescent analyses based on the isolation-with-migration model validate that the split between biogeographic regions north and south of 30°S has a historic origin. The signatures of the historic break in high dispersers is parsimoniously explained by the homogenizing effects of gene flow that have erased the genetic signatures, if ever existed, in high dispersers. Of the four species with structure across the break, only two had significant albeit very low levels of asymmetric migration across the transition zone. Historic processes have led to the current biogeographic and phylogeographic structure of marine species with limited dispersal along the north-central coast of Chile, with a strong lasting impact in their genetic structure.
Año: 2014
Palabras claves: Phylogeography, Biogeography, Haplotypes, Population genetics, Chile (country), Gene flow, Larvae, Marine biology.
Referencia APA: Haye, P., Segovia, N., Muñoz-Herrera, N., Gálvez, F., Martínez, A., & Meynard, A. et al. (2014). Phylogeographic Structure in Benthic Marine Invertebrates of the Southeast Pacific Coast of Chile with Differing Dispersal Potential. Plos ONE, 9(2), e88613.
Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile.
Perreault, M., Borgeaud, I., & Gaymer, C.
The ability of sea urchins to destroy kelp forests, leaving large areas stripped of vegetation and covered by sparse calcareous algae is well known. The reduction in active predators of sea urchins combined with their broad diet makes them an important factor in the structuring of subtidal benthic marine systems. In central and northern Chile, the sea urchin Tetrapygus niger is known to reduce the spread of the subtidal kelp Lessonia trabeculata. However, its impact on the different development stages of L. trabeculata has never been quantified or compared to other possible causes of the loss of material. The objective of this study was to quantify the grazing impact of T. niger on L. trabeculata at different stages of development (recruits, juveniles and adults). An exclusion experiment was conducted to evaluate the grazing effect of T. niger on kelp recruitment within a kelp bed, and kelp transplant experiments were conducted to quantify T. niger's impact on the stipes and fronds of juvenile and adult L. trabeculata. Our results showed that under natural sea urchin densities (10 ind. m− 2), T. niger prevented the recruitment of L. trabeculata. Tetrapygus niger completely consumed juvenile plants but only attacked the stipes of adult plants. Tetrapygus niger seems to use different feeding strategies depending on the ontogeny of the plant. Lessonia trabeculata seems unable to defend itself against the impact of intensive grazing by sea urchins, which may be the primary source of mortality of recruits and juveniles of L. trabeculata. However, T. niger's impact on adult plants is limited and shared with other herbivores that graze the fronds, such as fishes and spider crabs.
Año: 2014
Palabras claves: Chile; Herbivory; Lessonia trabeculata; Rocky subtidal; Sea urchin–kelp interaction; Tetrapygus niger.
Referencia APA: Perreault, M., Borgeaud, I., & Gaymer, C. (2014). Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile. Journal Of Experimental Marine Biology And Ecology, 453, 22-27.
Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile.
Aburto, J., Stotz, W., & Cundill, G.
In Chile, a Territorial User Rights for Fisheries system was developed to manage benthic fisheries. This system is referred to as Management Areas for the Exploitation of Benthic Resources. Management areas involved a shift from top-down control by governments to comanagement. We have analyzed the effects of a highly variable fishery, characterized by boom-and-bust cycles, on the governance of local institutions designed for resource management. We focused on a case study in north central Chile, in which the surf clam fishery experienced high levels of variability when the fishery was in an open access system. The management areas were established for the fishery in 1999. As a result, a set of rules for the fishery were created and enforced by fishers and local fishery authorities. Despite intense efforts on the part of all stakeholders, the fishery collapsed after three years of management area policy. This approach has been shown to be an effective management option for other species; however, for resources with boom-and-bust cycles, it is important to understand the response pattern of users confronting this spatial and temporal variability before the establishment of territorial user rights. Defining the appropriate spatial scale of the territorial rights could allow fishers to switch among different surf clam beds to maintain their livelihood and support the sustainability of local institutions for resource management.
Año: 2014
Palabras claves: Governance; management area; small-scale fishery; social-ecological; TURF.
Referencia APA: Aburto, J., Stotz, W., & Cundill, G. (2014). Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile. Ecology And Society, 19(1).
Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation.
Cárcamo, P., Garay-Flühmann, R., & Gaymer, C.
Recent studies have shown that social networks and their properties are key in the search for explanations for the success in the governance and management of natural resources. We investigated the structure and properties of inter-organizational social networks involved in the use and management of natural resources in a coastal marine ecosystem in northern Chile proposed as a possible marine protected area. We explored two network configurations: i) relations of collaboration and ii) relations of transfer and exchange of scientific knowledge and information useful to the management of natural resources and the decision-making process involved. Both networks showed little cohesion, with low values of centralization and density indicating a low flow of collaborative and exchange relations among different stakeholders. The knowledge network achieved greater levels of centralization than the collaboration network. National government agencies and fishermen organizations were the most powerful stakeholders in the collaboration network. National government agencies and universities were the most powerful stakeholders in the knowledge network. We found a disconnected network when analyzing the flows of collaboration and knowledge between different administrative operation levels that potentially would hamper the governance of this area. On the other hand, we identified stakeholders that would help to connect the network (bridging stakeholders). Additional analysis of stakeholders using influence-capacity matrix allowed us to identify key stakeholders for planning and implementing the new marine protected area, compare results with the network analysis, and propose network interventions. We propose combining Social Network Analysis with other methods of stakeholder analysis to produce more practical and implementable results. Our results are relevant for future interventions aimed at improving or implementing management and governance of coastal areas.
Año: 2014
Palabras claves:
Referencia APA: Cárcamo, P., Garay-Flühmann, R., & Gaymer, C. (2014). Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation. Ocean & Coastal Management, 91, 5-16.