Efectos de la acuicultura sobre las condiciones físicas, químicas y biológicas del sedimento
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2018
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La acuicultura ha tenido un fuerte incremento en los últimos cincuenta años en todo el mundo. Sin embargo, esta actividad está generando impactos negativos debido a los desechos que libera al medio. Tanto los cultivos intensivos de peces como de mitílidos generan un incremento de Amonios, Nitrógeno y Fosfato en la columna de agua, esto se traduce finalmente en una eutrofización de la columna de agua y enriquecimiento orgánico del fondo marino. Esto aumenta la actividad de bacterias que producen metabolitos del amonio y sulfato, alterando el potencial Redox y disminuyendo el pH, los cuales terminan por alterar la estructura comunitaria del bentos. En el presente trabajo se busca evaluar el impacto de la acuicultura sobre las características físicas y químicas del sedimento, como también sobre la estructura comunitaria de la macrofauna. La zona de estudio fue en la Región de los Lagos la cual se dividió en seis sub-zonas: Seno de Reloncaví, Calbuco, Tenaún, Dalcahue, Chiloé Central y Quellón donde cada una de las sub-zonas menores posee distintas intensidades de producción de salmónidos y mitílidos. Los muestreos fueron realizados encada sub-zona puntos cercanos a centros de cultivo de salmónidos y/o mitílidos. Es importante destacar que el diseño y ejecución de los muestreos fue realizado por el Instituto de Fomento Pesquero (IFOP) quien realiza un monitoreo anual en la zona. La similitud de las variables físicas y químicas, así como la estructura comunitaria entre distintas sub-zonas se evaluó mediante análisis de escalamiento multidimensional (MDS) y un Análisis de Similaridad (ANOSIM). Finalmente se calculó el AMBI y se estudió la calidad del sedimento asociado a la abundancia y riqueza de especies de la macrofauna bentónica mediante un análisis de escalamiento multidimensional (MDS) con el objetivo de evaluar si las distintas intensidades de producción entre las sub-zonas están afectando a la estructura comunitaria. Entre los resultados se observó que para las estaciones de muestreo cercanas a centros que cultivan salmónidos y mitílidos, como también las estaciones cercanas a centros que solo producen mitílidos presentaron menor similitud entre las sub-zonas con respecto a los parámetros físico y químicos lo que podría significar un mayor impacto en las sub-zonas donde se presenta una mayor cantidad de productividad. Cabe destacar que la zona de Quellón fue la zona que presentó más estaciones cercanas a centros de salmónidos y mitílidos, en las cuales fue donde se presentaron los mayores niveles de materia orgánica. Es así como, con los presentes resultados, la intensidad de la acuicultura presentada podría impactar en las variables físicas y químicas del sedimento, como también generar cambios en la composición de la macrofauna bentónica. Sin embargo, la gran cantidad de variables ambientales podrían estar opacando los resultados.
Aquaculture has grown sharply over the last fifty years worldwide. However, this activity is generating negative impacts due to the waste it releases to the environment. Both intensive fish and mussels crops generate an increase of Nitrogen and Phosphate in the water column, this finally translates into a eutrophication of the water column of the increase of deposition of organic matter on the seafloor. This increases the activity of bacteria that produce ammonium and sulfate metabolites, altering the Redox potential and lowering the pH, which end up altering the community structure of bentos. In the present work, we intend to evaluate the impact of aquaculture with respect to the contribution of organic matter from the intensive activity, looking for changes in the physical and chemical characteristics of benthos, as well as in the community structure. The parameters such as Redox, pH and total organic matter, together with the community attributes and the AMBI index are the parameters used to evaluate the relationships between the sedimentological characteristics and the benthiccommunities respectively. The study area was divided into sixsubzones: Seno de Reloncaví, Calbuco, Tenaún, Dalcahue, Chiloé Central and Quellón where each of the smaller areas has different production intensities. Sampling was carried out at points closeto salmonid or mitrilid centers and, on the other hand, at points close to centers with salmonid and mitrilid production. It is highlighted that the design and execution of the sampling was carried out by the Institute of Fisheries Promotion (IFOP) that performs an annual monitoring in the area. The similarity of the physical and chemical variables as well as the community structure between different zones was evaluated by multidimensional scaling analysis (MDS) and a similarity analysis (ANOSIM). Finally,AMBI was calculated and the sediment quality associated with the abundance and species richness of the benthic macrofauna was studied through a multidimensional scaling analysis (MDS) in order to evaluate if the different intensities of production betweenthe zones are affecting the community structure.Among the results, it was observed that for sampling stations close to centers that grow salmonids and mithylids, as well as stations close to centers that produce mithylids showed less similarity between zones with respect to physical and chemical parameters, which could mean a greater impact in these zones product of the centers. It should be noted that the area of Quellón was the area that presented more stations near salmonid and musselscenters, in which it was where the highest levels of organic matter were presented.Thus, with the present results, the intensity of the aquaculture presented could impact the physical and chemical variables of the sediment, as well as generate changes in the composition of the benthic macrofauna. However, the large number of environmental variables could be overshadowing the results.
Aquaculture has grown sharply over the last fifty years worldwide. However, this activity is generating negative impacts due to the waste it releases to the environment. Both intensive fish and mussels crops generate an increase of Nitrogen and Phosphate in the water column, this finally translates into a eutrophication of the water column of the increase of deposition of organic matter on the seafloor. This increases the activity of bacteria that produce ammonium and sulfate metabolites, altering the Redox potential and lowering the pH, which end up altering the community structure of bentos. In the present work, we intend to evaluate the impact of aquaculture with respect to the contribution of organic matter from the intensive activity, looking for changes in the physical and chemical characteristics of benthos, as well as in the community structure. The parameters such as Redox, pH and total organic matter, together with the community attributes and the AMBI index are the parameters used to evaluate the relationships between the sedimentological characteristics and the benthiccommunities respectively. The study area was divided into sixsubzones: Seno de Reloncaví, Calbuco, Tenaún, Dalcahue, Chiloé Central and Quellón where each of the smaller areas has different production intensities. Sampling was carried out at points closeto salmonid or mitrilid centers and, on the other hand, at points close to centers with salmonid and mitrilid production. It is highlighted that the design and execution of the sampling was carried out by the Institute of Fisheries Promotion (IFOP) that performs an annual monitoring in the area. The similarity of the physical and chemical variables as well as the community structure between different zones was evaluated by multidimensional scaling analysis (MDS) and a similarity analysis (ANOSIM). Finally,AMBI was calculated and the sediment quality associated with the abundance and species richness of the benthic macrofauna was studied through a multidimensional scaling analysis (MDS) in order to evaluate if the different intensities of production betweenthe zones are affecting the community structure.Among the results, it was observed that for sampling stations close to centers that grow salmonids and mithylids, as well as stations close to centers that produce mithylids showed less similarity between zones with respect to physical and chemical parameters, which could mean a greater impact in these zones product of the centers. It should be noted that the area of Quellón was the area that presented more stations near salmonid and musselscenters, in which it was where the highest levels of organic matter were presented.Thus, with the present results, the intensity of the aquaculture presented could impact the physical and chemical variables of the sediment, as well as generate changes in the composition of the benthic macrofauna. However, the large number of environmental variables could be overshadowing the results.
Notas
Tesis (Biólogo Marino)
Palabras clave
Acuicultura, Aspectos Ambientales, Sedimentos Marinos, Investigaciones, Contaminación Marina