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bioRxiv · 10.1101/2020.08.19.257626

Planktonic diatom assemblage seasonal diversity used to assess environmental health in a coastal wetland of southern Chile

Rios Henriquez, C.·Tobar, C. N.·Rau, J. R.·Cruces, F.·Fuentes, N.
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Abstract

Although planktonic diatoms are one of the most abundant taxonomic groups in coastal wetlands, their assemblages have not been used to determine the environmental health of these ecosystems. Studies of ecosystem environmental health have been based on other taxonomic groups; we propose that diatom genera diversity represents a viable alternative for this purpose. Thus, our aim was to determine the alpha and beta diversities of the planktonic diatom assemblage present in Caulin Bay, Chiloe Island (41{degrees} 49S; 73{degrees} 38O), southern Chile, during the austral winter and spring of the years 2012 and 2014. Inasmuch Caulin Bay is an important site for aquatic bird observation and conservation, hunting is prohibited on a national scale and, internationally, the site has been declared an Important Bird and Biodiversity Area (IBA). Our results indicate different diversities between sampling stations, but not between the years studied. In total, we recorded 53 diatom genera, of which the most abundant were Coscinodiscus (21.99%) and Cocconeis (16.23%). The study area presented high genera diversity (i.e., H(log2) >3.74) and beta diversity indicated that Caulin presents a low level of heterogeneity and is a low genera replacement environment. Consequently, we infer that Caulin Bay is productive and environmentally stable ecosystem. This leads us to conclude that diatom diversity determination is a viable alternative to establish aquatic ecosystem environmental health and we recommend that future conservation strategies be established for Caulin Bay. RESUMENSi bien las diatomeas planctonicas son uno de los grupos taxonomicos mas abundantes de los humedales costeros, sus ensambles no se han utilizado para determinar el estado ambiental de estos ecosistemas. Aunque se han realizado estudios de la salud ambiental de un ecosistema utilizando otros grupos taxonomicos, nosotros proponemos que la diversidad de generos de diatomeas representa una alternativa viable. Por lo tanto, el objetivo de este estudio fue determinar las diversidades alfa y beta del ensamble de diatomeas planctonicas presentes en la Bahia de Caulin, Isla de Chiloe (41 {degrees} 49S; 73 {degrees} 38O), sur de Chile, durante las temporadas de invierno y primavera austral de los anos 2012 y 2014. Bahia Caulin es un sitio importante para la observacion y conservacion de aves acuaticas por lo que a nivel nacional se ha prohibido la caza y a nivel internacional fue decretada un Area Importante para la Conservacion de Aves, AICA. Los resultados de este estudio indicaron diferencias en las diversidades entre las estaciones de muestreo, pero no entre los anos estudiados. En total, se identificaron 53 generos de diatomeas; los mas abundantes fueron Coscinodiscus (21,99%) y Cocconeis (16,23%). El area de estudio presento una alta diversidad de generos (i.e., H(log2) >3.74) y la diversidad beta indico que Caulin presento bajo nivel de heterogeneidad y es un entorno con bajo reemplazo de generos. Asi, inferimos que Bahia Caulin es un ecosistema productivo y ambientalmente estable, por lo cual concluimos que la determinacion de las diversidades de diatomeas es una alternativa para establecer la salud ambiental de los ecosistemas acuaticos y recomendamos establecer futuras estrategias de conservacion para Bahia Caulin. PALABRAS CLAVE: diatomeas, diversidades ecologicas, plancton, humedales costeros, desembocadura

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Rios Henriquez, C., Tobar, C. N., Rau, J. R., Cruces, F., Fuentes, N.. 2020-08-20. Planktonic diatom assemblage seasonal diversity used to assess environmental health in a coastal wetland of southern Chile. https://doi.org/10.1101/2020.08.19.257626

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