• Energy Research

An Olympus CKX41 inverted microscope connected to a digital camera (Motic 5.0) was used. Also, three electron microscopes were used: - Quanta FEG 250 (FEI, Hillsboro, Oregon, USA) in the laboratory of CIEN-UC, Facultad de Física, Pontificia Universidad Católica de Chile. - Quanta 250 (FEI, Hillsboro, Oregon, USA) in the laboratory of MEM, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile. - Quanta Inspect F50 (FEI, Hillsboro, Oregon, USA) in the laboratory of UICMA, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile. Images of main microplanktonic items (folders) obtained under inverted (mostly) and electronic microscope used to estimate biovolume and carbon biomass. Scale bar is shown on each picture and label of each image indicate the station ID (St.) and sampling depth (m). A table is provided with biovolume and equivalent spherical diameter calculations for each planktonic item.

An Olympus CKX41 inverted microscope connected to a digital camera (Motic 5.0) was used. Also, three electron microscopes were used: - Quanta FEG 250 (FEI, Hillsboro, Oregon, USA) in the laboratory of CIEN-UC, Facultad de Física, Pontificia Universidad Católica de Chile. - Quanta 250 (FEI, Hillsboro, Oregon, USA) in the laboratory of MEM, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile. - Quanta Inspect F50 (FEI, Hillsboro, Oregon, USA) in the laboratory of UICMA, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile. Images of main microplanktonic items (folders) obtained under inverted (mostly) and electronic microscope used to estimate biovolume and carbon biomass. Scale bar is shown on each picture and label of each image indicate the station ID (St.) and sampling depth (m). A table is provided with biovolume and equivalent spherical diameter calculations for each planktonic item.

AbstractThe ratio of inorganic nitrogen to phosphorus (NP) is projected to decrease in the Eastern Boundary Upwelling Systems (EBUS) due to warming of the surface waters. In an enclosure experiment, we employed two levels of NP ratios (10 and 5) for three distinct plankton communities collected along the coast of central Chile (33°S). The primary effect of the NP treatment was related to different concentrations of NO3, which directly influenced the biomass of phytoplankton. Additionally, low inorganic NP ratio reduced the seston NP and Chla-C ratios, and there were some effects on the plankton community composition, e.g. benefittingSynechococcusspp in some communities. One of the communities was clearly top down controlled and trophic transfer to grazers was up to 5.8% during the 12 day experiment. Overall, the initial plankton community composition was more important for seston stoichiometry and trophic transfer than the inorganic NP ratio. Any long term change in the plankton community structure will likely have greater impact than direct effects of a decreasing inorganic NP ratio on the Humboldt Current ecosystem.

AbstractThe ratio of inorganic nitrogen to phosphorus (NP) is projected to decrease in the Eastern Boundary Upwelling Systems (EBUS) due to warming of the surface waters. In an enclosure experiment, we employed two levels of NP ratios (10 and 5) for three distinct plankton communities collected along the coast of central Chile (33°S). The primary effect of the NP treatment was related to different concentrations of NO3, which directly influenced the biomass of phytoplankton. Additionally, low inorganic NP ratio reduced the seston NP and Chla-C ratios, and there were some effects on the plankton community composition, e.g. benefittingSynechococcusspp in some communities. One of the communities was clearly top down controlled and trophic transfer to grazers was up to 5.8% during the 12 day experiment. Overall, the initial plankton community composition was more important for seston stoichiometry and trophic transfer than the inorganic NP ratio. Any long term change in the plankton community structure will likely have greater impact than direct effects of a decreasing inorganic NP ratio on the Humboldt Current ecosystem.