Transferencia de contaminantes desde la matriz acuática al erizo de mar negro (Tetrapygus niger) con Macrocystis pyrifera como intermediario
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2021
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es
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Universidad Andrés Bello
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Los contaminantes como metales pesados (MPs) e hidrocarburos aromáticos
policíclicos (PAHs) se encuentran distribuidos a lo largo de los ecosistemas costeros, con
mayores concentraciones en las zonas con un alto impacto industrial. Estos pueden ser
transportados por medios naturales como las corrientes oceánicas, atmosféricas, por
organismos altamente migratorios y/o por la actividad antropogénica. La presencia de estos
contaminantes puede generar efectos negativos en los ecosistemas marinos. Tanto los MPs
como los PAHs pueden ser bioacumulados e incluso biomagnificarse a lo largo de la trama
trófica. Estos contaminantes pueden gatillar una sobreproducción de especies reactivas de
oxígeno (EROs) generando un estrés oxidativo, provocando la oxidación de biomoléculas y
estructuras celulares.
Entre los organismos capaces de bioacumular contaminantes, principalmente de MPs,
destaca el alga parda Macrocystis pyrifera, productor primario, categorizada como ingeniero
ecosistémico. Esta especie en particular al desprenderse del sustrato puede estar a la deriva
por meses, dispersándose por medio de las corrientes marinas. Durante este tiempo gran parte
del individuo es viable y hasta puede generar estructuras reproductivas. Al varar en la costa,
esta puede servir de alimento para los herbívoros en las playas otorgando subsidio trófico.
Uno de los organismos que preferentemente se alimenta de algas varadas en la playa, como
de M. pyrifera, es el erizo de mar Tetrapygus niger. Este equinodermo es una especie clave
para los ecosistemas costeros, modulando la composición algal.
Bajo este contexto este trabajo evaluó la capacidad de los individuos de M. pyrifera
provenientes de una zona con alto impacto industrial de ser una fuente potencial de
contaminantes a zonas con bajo impacto y los efectos en el herbívoro T. niger y su
descendencia. Para esto se cultivaron individuos adultos de M. pyrifera provenientes de
Algarrobo (NIZ) en la caleta de Horcón (HIZ) por 60 días. Transcurrido el tiempo de cultivo,
se analizó el tejido algal para PAHs, y además fue utilizado para alimentar individuos de T.
niger. Posteriormente, se extrajeron las gónadas de T. niger para su posterior análisis de
PAHs. Adicionalmente, se recolectaron individuos de M. pyrifera y T. niger desde las poblaciones naturales de NIZ y HIZ para el análisis de metales. Los resultados de los análisis
reportan que solo se detectó naftaleno (NAF) en M. pyrifera y presentó una mayor
concentración en HIZ con respecto a NIZ. Por otra parte, los MPs presentaron mayores
concentraciones en HIZ, exceptuando Pb, el que presentó mayores concentraciones en NIZ
tanto en el tejido algal como en las gónadas de erizo. Por último, tanto el factor de
concentración (FBC) y el factor de biomagnificación (FBM) fueron mayores principalmente
en HIZ con algunas excepciones (Pb y Cd). Estos resultados sugieren la transferencia de
desde la columna de agua a T. niger por medio de la dieta, lo cual no se evidenció para PAHs.
Para demonstrar los efectos negativos en T. niger al ser alimentado con algas
contaminadas, se realizó un seguimiento del consumo y el crecimiento durante el
experimento de alimentación y luego al realizar la liberación de gametos se calculó la
fertilidad para cada tratamiento experimental. Posteriormente, se realizó un seguimiento del
desarrollo temprano post fecundación. Los resultados evidencian que los erizos del
tratamiento HIZ presentaron un crecimiento y una fertilidad menor con respecto al
tratamiento NIZ. El tratamiento HIZ presentó un retraso en el desarrollo en comparación con
NIZ de dos días, explicado por la abundancia de larvas pluteo de 2 brazos malformadas (10-
15%) durante la mayor parte del cultivo. Las larvas de 4 brazos malformadas mostraron un
aumento constante llegando al 37% del cultivo. Así los contaminantes ingeridos por los
erizos pueden ser transferidos a su descendencia y causar efectos negativos en su desarrollo
temprano.
Por último, dado que los organismos están expuestos a una mezcla de contaminantes
en vez de un único tóxico, estos están sujetos a efectos combinados e interacciones entre los
contaminantes, las cuales pueden ser aditivas, sinérgicas o antagónicas, principalmente. Para
comprender estos efectos combinados, se expusieron individuos de M. pyrifera a Cu, Cd y
PAHs y se analizó su respuesta a nivel molecular, específicamente en el perfil de ácidos
grasos. Los resultados demuestran que M. pyrifera presenta una respuesta diferencial en el
perfil de ácidos grasos libres y derivados oxidados dependiendo de las mezclas de
contaminantes. Esto podría generar un efecto indirecto negativo de los contaminantes en
herbívoros por medio de un cambio cuantitativo y cualitativo de la composición en su dieta. Según los resultados obtenidos en esta investigación M. pyrifera podría formar parte
de los mecanismos de dispersión de contaminantes y estos pueden generan un efecto negativo
tanto directo como indirecto en herbívoros, en este caso en el erizo negro T. niger. Se sugieren
investigaciones más específicas en las dinámicas de transferencias de metales, como el
metabolismo de PAHs, para comprender a mayor cabalidad los efectos en los ecosistemas
marinos y sus implicancias en la salud humana.
Pollutants such as heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAH) are found throughout coastal ecosystems, with higher concentrations in urbanized areas and with a high industrial impact. These can be transported by natural mechanisms such as ocean currents, atmospheric currents, by highly migratory organisms and/or by anthropogenic activity. The presence of these pollutants may generate negative effects in marine ecosystems. Both HMs and PAHs can be bioaccumulated by organisms and even biomagnified throughout the trophic web. These pollutants can trigger an overproduction of reactive oxygen species (ROS) generating oxidative stress, causing the oxidation of biomolecules and cellular structures. Among the organisms capable to bioacumulate pollutans, mainly of HMs, the brown alga Macrocystis pyrifera stands out, primary producer and categorized as an ecosystem engineer. This species, when detached can drift for months, dispersed by marine currents. During this time, a large part of the individual is viable and can even generate reproductive structures. When it lands on a coast, it can serve as food for herbivores on the beaches, granting trophic subsidy. One of the organisms that prefers to feed on beach-washed algae, is the black sea urchin Tetrapygus niger. This echinoderm is a key species for coastal ecosystems, modulating the algal composition. Under this context, this work aims to evaluate the ability of M. pyrifera to be a potential source of pollutants in areas with low impact if it is detached from an area with a high load of toxic substances and the effects on the herbivore T. niger and their offspring. To Achieve this objective M. pyrifera individuals from Algarrobo (NIZ) were cultivated in Horcón (HIZ) for 60 days. After the cultivation time, the algal tissue was analyzed for PAHs, and it was also used to feed T. niger. Subsequently, the T. niger gonads were extracted for PAHs analysis. Additionally, M. pyrifera and T. niger individuals were collected from NIZ and HIZ natural population for heavy metal analysis. The results show that only naphtalene was detected in M. pyrifera and presented a higher concentration in HIZ in respect with NIZ. On the other hand, the MPs presented a higher concentration in HIZ, except for Pb, which presented higher concentrations in NIZ, both in the algal tissue and in the sea urchin gonads. Finally, both the bioconcentration factor (BCF) and the biomagnification factor (BMF) were higher mainly in HIZ with some exceptions (Pb and Cd). These results suggest the transfer of heavy metal from the water column to T. niger, from diet, which was not evidenced for PAHs. To demonstrate the negative effects on T. niger when fed with contaminated algae, consumption and growth were monitored during the feeding experiment and then, when the gametes were released, the fertility of each treatment was measured. Then, post-fertilization early development was followed. The results show that HIZ sea urchins had lower growth and fertility compared to the NIZ treatment. The HIZ treatment presented a delay in development compared to NIZ of two days, explained by the abundance of malformed 2-arm plutei larvae (10-15%) during most of the culture. The 4-arm malformed larvae showed a constant increase reaching 37% of the culture. Thus, the pollutants ingested by sea urchin can be transferred to their offspring and cause negative effects on their early development. Finally, since organisms are exposed to a mixture of pollutants instead of a single toxin, they are subject to combined effects and interaction between pollutants, which can be additive, synergistic, or antagonistic. To understand these combined effects, individuals of M. pyrifera were exposed to Cu, Cd and PAHs and their response was analyzed at a molecular level, specifically in the fatty acid profile. The result show that M. pyrifera presents a differential response in the profile of free fatty acids and oxidized derivatives depending on the mixture of pollutants. This could generate a negative indirect effect of the pollutants in herbivores Through a quantitative and qualitative change of the composition in their diet. According to the results obtained in this research, M. pyrifera could be part of the pollutant dispersal mechanisms and these can generate a negative effect both directly and indirectly in herbivores, in this case in the black hedgehog T. niger. More specific research on the dynamics of metal transfers, such as PAH metabolism, is suggested to better understand the effects on marine ecosystems and their implications for human health.
Pollutants such as heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAH) are found throughout coastal ecosystems, with higher concentrations in urbanized areas and with a high industrial impact. These can be transported by natural mechanisms such as ocean currents, atmospheric currents, by highly migratory organisms and/or by anthropogenic activity. The presence of these pollutants may generate negative effects in marine ecosystems. Both HMs and PAHs can be bioaccumulated by organisms and even biomagnified throughout the trophic web. These pollutants can trigger an overproduction of reactive oxygen species (ROS) generating oxidative stress, causing the oxidation of biomolecules and cellular structures. Among the organisms capable to bioacumulate pollutans, mainly of HMs, the brown alga Macrocystis pyrifera stands out, primary producer and categorized as an ecosystem engineer. This species, when detached can drift for months, dispersed by marine currents. During this time, a large part of the individual is viable and can even generate reproductive structures. When it lands on a coast, it can serve as food for herbivores on the beaches, granting trophic subsidy. One of the organisms that prefers to feed on beach-washed algae, is the black sea urchin Tetrapygus niger. This echinoderm is a key species for coastal ecosystems, modulating the algal composition. Under this context, this work aims to evaluate the ability of M. pyrifera to be a potential source of pollutants in areas with low impact if it is detached from an area with a high load of toxic substances and the effects on the herbivore T. niger and their offspring. To Achieve this objective M. pyrifera individuals from Algarrobo (NIZ) were cultivated in Horcón (HIZ) for 60 days. After the cultivation time, the algal tissue was analyzed for PAHs, and it was also used to feed T. niger. Subsequently, the T. niger gonads were extracted for PAHs analysis. Additionally, M. pyrifera and T. niger individuals were collected from NIZ and HIZ natural population for heavy metal analysis. The results show that only naphtalene was detected in M. pyrifera and presented a higher concentration in HIZ in respect with NIZ. On the other hand, the MPs presented a higher concentration in HIZ, except for Pb, which presented higher concentrations in NIZ, both in the algal tissue and in the sea urchin gonads. Finally, both the bioconcentration factor (BCF) and the biomagnification factor (BMF) were higher mainly in HIZ with some exceptions (Pb and Cd). These results suggest the transfer of heavy metal from the water column to T. niger, from diet, which was not evidenced for PAHs. To demonstrate the negative effects on T. niger when fed with contaminated algae, consumption and growth were monitored during the feeding experiment and then, when the gametes were released, the fertility of each treatment was measured. Then, post-fertilization early development was followed. The results show that HIZ sea urchins had lower growth and fertility compared to the NIZ treatment. The HIZ treatment presented a delay in development compared to NIZ of two days, explained by the abundance of malformed 2-arm plutei larvae (10-15%) during most of the culture. The 4-arm malformed larvae showed a constant increase reaching 37% of the culture. Thus, the pollutants ingested by sea urchin can be transferred to their offspring and cause negative effects on their early development. Finally, since organisms are exposed to a mixture of pollutants instead of a single toxin, they are subject to combined effects and interaction between pollutants, which can be additive, synergistic, or antagonistic. To understand these combined effects, individuals of M. pyrifera were exposed to Cu, Cd and PAHs and their response was analyzed at a molecular level, specifically in the fatty acid profile. The result show that M. pyrifera presents a differential response in the profile of free fatty acids and oxidized derivatives depending on the mixture of pollutants. This could generate a negative indirect effect of the pollutants in herbivores Through a quantitative and qualitative change of the composition in their diet. According to the results obtained in this research, M. pyrifera could be part of the pollutant dispersal mechanisms and these can generate a negative effect both directly and indirectly in herbivores, in this case in the black hedgehog T. niger. More specific research on the dynamics of metal transfers, such as PAH metabolism, is suggested to better understand the effects on marine ecosystems and their implications for human health.
Notas
Tesis (Doctor en Medicina de la Conservación)
Este trabajo fue financiado por FONDECYT N° 1170881, Research Initiation Project 2019 UNAB, ANID PIA/BASAL FB0002 y ANID Millennium Science Initiative Program ICN 2019_015.
Este trabajo fue financiado por FONDECYT N° 1170881, Research Initiation Project 2019 UNAB, ANID PIA/BASAL FB0002 y ANID Millennium Science Initiative Program ICN 2019_015.
Palabras clave
Contaminantes, Metales Pesados, Algas Marinas, Análisis, Erizos de Mar, Investigaciones