Presentation Title

Diurnal Nutrient Cycling in Macrocystis pyrifera

Faculty Mentor

Adriane Jones, Diane Kim, Ignacio Navarette

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

CREVELING 23

Session

POSTER 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Our reliance on fossil fuels for energy is not sustainable. Using fossil fuels for energy emits high amounts of carbon dioxide into the environment, increasing global temperatures and promoting ocean acidification. Researchers are investigating the potential for the giant kelp Macrocystis pyrifera to be used as a renewable biofuel. Kelp growth is limited by two resources: sunlight and nutrients. To achieve maximum growth, researchers plan to create large kelp farms in the open oceans and physically cycle the kelp, so that they receive sunlight at the surface during the day and nutrients at depth during the night. The ability of M. pyrifera to uptake nutrients in the dark has not been widely studied, and this is variable that is most unknown in the project. Kelp was harvested from beaches in Santa Catalina Island, CA and the blades were designated to one of four treatments. The experiment occurred in an incubator at 13oC and a light intensity of 76 umol m2s-1 for 7 days. The nutrient rich treatment was amended with a nitrate concentration of 24 uM. Nitrate levels was measured daily using two methods. Results demonstrated that kelp blades kept in an environment with poor nutrients throughout a light dark cycle grew the most. Kelp in nutrient-poor conditions in the light and nutrient-rich conditions in the dark had the second greatest growth of all, suggesting kelp can, in fact, take up nutrients in the dark. Elevated nitrate and phosphate concentrations administered to the nutrient rich condition did not seem to affect growth of the individual blades. These results suggest that kelp might grow best at lower than expected levels of nutrients and may not need to be cycled to depths with high levels of nitrate. This could greatly improve the feasibility of constructing large ocean kelp farms in the future.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Diurnal Nutrient Cycling in Macrocystis pyrifera

CREVELING 23

Our reliance on fossil fuels for energy is not sustainable. Using fossil fuels for energy emits high amounts of carbon dioxide into the environment, increasing global temperatures and promoting ocean acidification. Researchers are investigating the potential for the giant kelp Macrocystis pyrifera to be used as a renewable biofuel. Kelp growth is limited by two resources: sunlight and nutrients. To achieve maximum growth, researchers plan to create large kelp farms in the open oceans and physically cycle the kelp, so that they receive sunlight at the surface during the day and nutrients at depth during the night. The ability of M. pyrifera to uptake nutrients in the dark has not been widely studied, and this is variable that is most unknown in the project. Kelp was harvested from beaches in Santa Catalina Island, CA and the blades were designated to one of four treatments. The experiment occurred in an incubator at 13oC and a light intensity of 76 umol m2s-1 for 7 days. The nutrient rich treatment was amended with a nitrate concentration of 24 uM. Nitrate levels was measured daily using two methods. Results demonstrated that kelp blades kept in an environment with poor nutrients throughout a light dark cycle grew the most. Kelp in nutrient-poor conditions in the light and nutrient-rich conditions in the dark had the second greatest growth of all, suggesting kelp can, in fact, take up nutrients in the dark. Elevated nitrate and phosphate concentrations administered to the nutrient rich condition did not seem to affect growth of the individual blades. These results suggest that kelp might grow best at lower than expected levels of nutrients and may not need to be cycled to depths with high levels of nitrate. This could greatly improve the feasibility of constructing large ocean kelp farms in the future.