Shannon Meseck | Northeast Fisheries Science Center, NOAA (original) (raw)
Papers by Shannon Meseck
Archives of Environmental Contamination and Toxicology, 2008
Juvenile bay scallops (7.2–26.4 mm) were exposed for 72 h to different concentrations of un-ioniz... more Juvenile bay scallops (7.2–26.4 mm) were exposed for 72 h to different concentrations of un-ionized ammonia, nitrite, or nitrate. Using the Trimmed Spearman Karber method, 50% lethal concentrations (LC50) and 95% confidence limits were calculated individually for each. Un-ionized ammonia concentrations above 1.0 mg N-NH3/L resulted in 100% scallop mortality within 72 h. The 72-h LC50 for un-ionized ammonia was calculated at 0.43 mg N/L. At nitrite concentrations of 800 mg N/L or higher 100% mortality was observed. The 72-h LC50 for nitrite was calculated at 345 mg N/L. Nitrate was the least toxic, with 100% mortality observed at a concentration of 5000 mg N/L. The calculated nitrate 72-h LC50 was 4453 mg N/L. Our results indicate that un-ionized ammonia is the most lethal nitrogenous waste component to bay scallops.
Aquaculture, 2007
In aquaculture, large volumes of phytoplankton are often grown outdoors to reduce costs. However,... more In aquaculture, large volumes of phytoplankton are often grown outdoors to reduce costs. However, growing microalgae in an environment not as well-controlled as in the laboratory can lead to unwanted phytoplankton, including cyanobacteria, contaminating a culture. A cyanobacterial contaminant was isolated from an outdoor culture of Tetraselmis chui (PLY429) at the Milford Laboratory. This study investigated the growth of PLY429 and the cyanobacterium in pure cultures and a mixed culture in a pH range of 6.5-9.5. The division of PLY429 was greater at a pH range of 7.0-8.0; whereas, for the cyanobacterium, higher growth was obtained at pH 8.0-9.0. Results from combined cultures of PLY429 and the cyanobacterium grown at various pHs indicated that maintaining pH near 7.1 yields higher growth of PLY429 than those of the cyanobacterium. These findings suggest that controlling pH may reduce the population of a cyanobacterial contaminant in an aquaculture feed culture. Published by Elsevier B.V.
Limnology and Oceanography, 2006
A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankto... more A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankton biomass, dissolved selenium concentrations (selenite, selenate, and organic selenide), and particulate selenium concentrations (selenite + selenate, elemental selenium, and organic selenide) in the San Francisco Bay estuary. Model-generated estuarine profiles of total dissolved selenium reproduced observed estuarine profiles at a confidence interval of 91-99% for 8 different years under various environmental conditions. The model accurately reproduced the observed dissolved speciation at confidence intervals of 81-98% for selenite, 72-91% for selenate, and 60-96% for organic selenide. For particulate selenium, model-simulated estuarine profiles duplicated the observed behavior of total particulate selenium (76-93%), elemental selenium (80-97%), selenite + selenate (77-82%), and organic selenide (70-83%). Discrepancies between model simulations and the observed data provided insights into the estuarine biogeochemical cycle of selenium that were largely unknown (e.g., adsorption/desorption). Forecasting simulations investigated how an increase in the discharge from the San Joaquin River and varying refinery inputs affect total dissolved and particulate selenium within the estuary. These model runs indicate that during high river flows the refinery signal is undetectable, but when river flow is low (70day residence time) total particle-associated selenium concentrations can increase to .2 mg g 21 . Increasing the San Joaquin River discharge could also increase the total particle-associated selenium concentrations to .1 mg g 21 . For both forecasting simulations, particle-associated selenium was predicted to be higher than current conditions and reached levels where selenium could accumulate in the estuarine food web.
Aquaculture, 2005
Light intensity, day length, and nutrient concentrations are important factors regulating the gro... more Light intensity, day length, and nutrient concentrations are important factors regulating the growth of phytoplankton. To reduce culturing costs, natural sunlight and greenhouses can be used to minimize the amount of artificial light needed for algal growth. However, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment. This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (strain PLY429)-an algal strain used widely as an aquaculture feed. PLY429 was grown aseptically for 28 days under three different light intensities (220, 110, and 73 AEinst. m À2 s À1 ) and four different light:dark cycles (24:0, 16:8; 12:12; 8:16). Growth and net nutrient-uptake rates for PLY429 were calculated for each treatment. Longer day length and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities. PLY429 cultures that were exposed to only 8 h of light had the slowest growth and utilization of nutrients. These findings suggest that day length is important in determining growth and nutrient uptake in PLY429; at a latitude of 418N, artificial light will need to be added to algal cultures in a greenhouse to increase both day length and total daily light input. D
Journal of Shellfish Research, 2007
Estuaries and Coasts, 2009
The enzyme-labeled fluorescence (ELF-97®) substrate produces an insoluble, fluorescent yellow-gre... more The enzyme-labeled fluorescence (ELF-97®) substrate produces an insoluble, fluorescent yellow-green product at the site of alkaline-phosphatase (AP) activity. Fifteen coastal phytoplankton species were tested to determine if AP activity could be detected in phosphate-depleted media. All species tested, except Synechococcus bacillaris, expressed AP activity. Subsequently, threshold concentrations of soluble reactive phosphate (SRP) at which AP activity could be detected by ELF-97® were determined for Chaetoceros neogracile, Chlorella autotrophica, Isochrysis sp., Prorocentrum minimum, and Tetraselmis chui. Microalgal species differed significantly in the SRP concentration at which AP activity was first detectable (10.1–16.4 µM), well above concentrations normally considered limiting for phytoplankton. P. minimum began to express AP activity at a higher SRP concentration than the other algal species; this may be attributable to a relatively high DNA/cell ratio in P. minimum, compared to the other phytoplankton. Thus, phytoplankton species may respond to phosphorus deficiency at high SRP concentrations.
Journal of Applied Phycology, 2007
Light, nutrients, temperature, pH, and salinity are important factors in controlling the growth o... more Light, nutrients, temperature, pH, and salinity are important factors in controlling the growth of phytoplankton and bacterioplankton. Supply of key nutrients to these communities can result in mutualistic or competitive relationships between bacterioplankton and phytoplankton. In this study, we investigated growth and uptake of nutrients by the marine prasinophyte flagellate Tetraselmis chui (strain PLY429) in the presence and absence of a community of bacterioplankton at two pH levels. Growth of PLY429 and total nutrient uptake were calculated for each treatment. The addition of bacterioplankton resulted in lower growth rates of PLY429, but the removal of ammonium was greater in those cultures with bacterioplankton present. The division rate of PLY429 was affected by pH; however, pH changes did not result in different uptake rates of nitrate, ammonium, or phosphate by the mixed algal and bacterial assemblage. These findings suggest that bacterioplankton and phytoplankton were competing for ammonium and that a lower pH resulted in more rapid algal growth.
Aquaculture, 2005
Light intensity, day length, and nutrient concentrations are important factors regulating the gro... more Light intensity, day length, and nutrient concentrations are important factors regulating the growth of phytoplankton. To reduce culturing costs, natural sunlight and greenhouses can be used to minimize the amount of artificial light needed for algal growth. However, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment. This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (strain PLY429)-an algal strain used widely as an aquaculture feed. PLY429 was grown aseptically for 28 days under three different light intensities (220, 110, and 73 AEinst. m À2 s À1 ) and four different light:dark cycles (24:0, 16:8; 12:12; 8:16). Growth and net nutrient-uptake rates for PLY429 were calculated for each treatment. Longer day length and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities. PLY429 cultures that were exposed to only 8 h of light had the slowest growth and utilization of nutrients. These findings suggest that day length is important in determining growth and nutrient uptake in PLY429; at a latitude of 418N, artificial light will need to be added to algal cultures in a greenhouse to increase both day length and total daily light input. D
Archives of Environmental Contamination and Toxicology, 2008
Juvenile bay scallops (7.2–26.4 mm) were exposed for 72 h to different concentrations of un-ioniz... more Juvenile bay scallops (7.2–26.4 mm) were exposed for 72 h to different concentrations of un-ionized ammonia, nitrite, or nitrate. Using the Trimmed Spearman Karber method, 50% lethal concentrations (LC50) and 95% confidence limits were calculated individually for each. Un-ionized ammonia concentrations above 1.0 mg N-NH3/L resulted in 100% scallop mortality within 72 h. The 72-h LC50 for un-ionized ammonia was calculated at 0.43 mg N/L. At nitrite concentrations of 800 mg N/L or higher 100% mortality was observed. The 72-h LC50 for nitrite was calculated at 345 mg N/L. Nitrate was the least toxic, with 100% mortality observed at a concentration of 5000 mg N/L. The calculated nitrate 72-h LC50 was 4453 mg N/L. Our results indicate that un-ionized ammonia is the most lethal nitrogenous waste component to bay scallops.
Aquaculture, 2007
In aquaculture, large volumes of phytoplankton are often grown outdoors to reduce costs. However,... more In aquaculture, large volumes of phytoplankton are often grown outdoors to reduce costs. However, growing microalgae in an environment not as well-controlled as in the laboratory can lead to unwanted phytoplankton, including cyanobacteria, contaminating a culture. A cyanobacterial contaminant was isolated from an outdoor culture of Tetraselmis chui (PLY429) at the Milford Laboratory. This study investigated the growth of PLY429 and the cyanobacterium in pure cultures and a mixed culture in a pH range of 6.5-9.5. The division of PLY429 was greater at a pH range of 7.0-8.0; whereas, for the cyanobacterium, higher growth was obtained at pH 8.0-9.0. Results from combined cultures of PLY429 and the cyanobacterium grown at various pHs indicated that maintaining pH near 7.1 yields higher growth of PLY429 than those of the cyanobacterium. These findings suggest that controlling pH may reduce the population of a cyanobacterial contaminant in an aquaculture feed culture. Published by Elsevier B.V.
Limnology and Oceanography, 2006
A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankto... more A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankton biomass, dissolved selenium concentrations (selenite, selenate, and organic selenide), and particulate selenium concentrations (selenite + selenate, elemental selenium, and organic selenide) in the San Francisco Bay estuary. Model-generated estuarine profiles of total dissolved selenium reproduced observed estuarine profiles at a confidence interval of 91-99% for 8 different years under various environmental conditions. The model accurately reproduced the observed dissolved speciation at confidence intervals of 81-98% for selenite, 72-91% for selenate, and 60-96% for organic selenide. For particulate selenium, model-simulated estuarine profiles duplicated the observed behavior of total particulate selenium (76-93%), elemental selenium (80-97%), selenite + selenate (77-82%), and organic selenide (70-83%). Discrepancies between model simulations and the observed data provided insights into the estuarine biogeochemical cycle of selenium that were largely unknown (e.g., adsorption/desorption). Forecasting simulations investigated how an increase in the discharge from the San Joaquin River and varying refinery inputs affect total dissolved and particulate selenium within the estuary. These model runs indicate that during high river flows the refinery signal is undetectable, but when river flow is low (70day residence time) total particle-associated selenium concentrations can increase to .2 mg g 21 . Increasing the San Joaquin River discharge could also increase the total particle-associated selenium concentrations to .1 mg g 21 . For both forecasting simulations, particle-associated selenium was predicted to be higher than current conditions and reached levels where selenium could accumulate in the estuarine food web.
Aquaculture, 2005
Light intensity, day length, and nutrient concentrations are important factors regulating the gro... more Light intensity, day length, and nutrient concentrations are important factors regulating the growth of phytoplankton. To reduce culturing costs, natural sunlight and greenhouses can be used to minimize the amount of artificial light needed for algal growth. However, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment. This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (strain PLY429)-an algal strain used widely as an aquaculture feed. PLY429 was grown aseptically for 28 days under three different light intensities (220, 110, and 73 AEinst. m À2 s À1 ) and four different light:dark cycles (24:0, 16:8; 12:12; 8:16). Growth and net nutrient-uptake rates for PLY429 were calculated for each treatment. Longer day length and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities. PLY429 cultures that were exposed to only 8 h of light had the slowest growth and utilization of nutrients. These findings suggest that day length is important in determining growth and nutrient uptake in PLY429; at a latitude of 418N, artificial light will need to be added to algal cultures in a greenhouse to increase both day length and total daily light input. D
Journal of Shellfish Research, 2007
Estuaries and Coasts, 2009
The enzyme-labeled fluorescence (ELF-97®) substrate produces an insoluble, fluorescent yellow-gre... more The enzyme-labeled fluorescence (ELF-97®) substrate produces an insoluble, fluorescent yellow-green product at the site of alkaline-phosphatase (AP) activity. Fifteen coastal phytoplankton species were tested to determine if AP activity could be detected in phosphate-depleted media. All species tested, except Synechococcus bacillaris, expressed AP activity. Subsequently, threshold concentrations of soluble reactive phosphate (SRP) at which AP activity could be detected by ELF-97® were determined for Chaetoceros neogracile, Chlorella autotrophica, Isochrysis sp., Prorocentrum minimum, and Tetraselmis chui. Microalgal species differed significantly in the SRP concentration at which AP activity was first detectable (10.1–16.4 µM), well above concentrations normally considered limiting for phytoplankton. P. minimum began to express AP activity at a higher SRP concentration than the other algal species; this may be attributable to a relatively high DNA/cell ratio in P. minimum, compared to the other phytoplankton. Thus, phytoplankton species may respond to phosphorus deficiency at high SRP concentrations.
Journal of Applied Phycology, 2007
Light, nutrients, temperature, pH, and salinity are important factors in controlling the growth o... more Light, nutrients, temperature, pH, and salinity are important factors in controlling the growth of phytoplankton and bacterioplankton. Supply of key nutrients to these communities can result in mutualistic or competitive relationships between bacterioplankton and phytoplankton. In this study, we investigated growth and uptake of nutrients by the marine prasinophyte flagellate Tetraselmis chui (strain PLY429) in the presence and absence of a community of bacterioplankton at two pH levels. Growth of PLY429 and total nutrient uptake were calculated for each treatment. The addition of bacterioplankton resulted in lower growth rates of PLY429, but the removal of ammonium was greater in those cultures with bacterioplankton present. The division rate of PLY429 was affected by pH; however, pH changes did not result in different uptake rates of nitrate, ammonium, or phosphate by the mixed algal and bacterial assemblage. These findings suggest that bacterioplankton and phytoplankton were competing for ammonium and that a lower pH resulted in more rapid algal growth.
Aquaculture, 2005
Light intensity, day length, and nutrient concentrations are important factors regulating the gro... more Light intensity, day length, and nutrient concentrations are important factors regulating the growth of phytoplankton. To reduce culturing costs, natural sunlight and greenhouses can be used to minimize the amount of artificial light needed for algal growth. However, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment. This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (strain PLY429)-an algal strain used widely as an aquaculture feed. PLY429 was grown aseptically for 28 days under three different light intensities (220, 110, and 73 AEinst. m À2 s À1 ) and four different light:dark cycles (24:0, 16:8; 12:12; 8:16). Growth and net nutrient-uptake rates for PLY429 were calculated for each treatment. Longer day length and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities. PLY429 cultures that were exposed to only 8 h of light had the slowest growth and utilization of nutrients. These findings suggest that day length is important in determining growth and nutrient uptake in PLY429; at a latitude of 418N, artificial light will need to be added to algal cultures in a greenhouse to increase both day length and total daily light input. D