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Seasonal Changes in Plankton Food Web Structure and Carbon Dioxide Flux from Southern California Reservoirs.

Adamczyk EM, Shurin JB - PLoS ONE (2015)

Bottom Line: We sampled three reservoirs in San Diego, California, weekly for one year.We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m(-2) day(-1). pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs.Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Sciences, Section of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, United States of America.

ABSTRACT
Reservoirs around the world contribute to cycling of carbon dioxide (CO2) with the atmosphere, but there is little information on how ecosystem processes determine the absorption or emission of CO2. Reservoirs are the most prevalent freshwater systems in the arid southwest of North America, yet it is unclear whether they sequester or release CO2 and therefore how water impoundment impacts global carbon cycling. We sampled three reservoirs in San Diego, California, weekly for one year. We measured seasonal variation in the abundances of bacteria, phytoplankton, and zooplankton, as well as water chemistry (pH, nutrients, ions, dissolved organic carbon [DOC]), which were used to estimate partial pressure of CO2 (pCO2), and CO2 flux. We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m(-2) day(-1). pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs. Abundances of microbes (bacteria) peaked in the winter along with pCO2, while phytoplankton, nutrients, zooplankton and DOC were all unrelated to pCO2. Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton.

No MeSH data available.


Twenty-four major reservoirs in San Diego County, California, USA http://www.sdcwa.org/san-diego-county-water-sources (http://www.sdcwa.org/reservoirs).Barret (BA); Cuyamaca (CU); Dixon (DI); El Capitan (CAP); Henshaw (HE); Hodges (HO); Jennings (JE); Loveland (LOV); Lower Otay (LO); Maerkle (MA); Miramar (MIR); Morena (MO); Murray (MUR); Olivenhain (OL); Poway (POW); Ramona (RA); Red Mountain (RD MO); San Dieguito (SN DG); San Vicente (SN VI); Sutherland (SL); Sweetwater (SW); Turner (TR); Upper Otay (UP OT); Wohlford (WF). The black points indicate the three reservoirs we sampled.
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pone.0140464.g001: Twenty-four major reservoirs in San Diego County, California, USA http://www.sdcwa.org/san-diego-county-water-sources (http://www.sdcwa.org/reservoirs).Barret (BA); Cuyamaca (CU); Dixon (DI); El Capitan (CAP); Henshaw (HE); Hodges (HO); Jennings (JE); Loveland (LOV); Lower Otay (LO); Maerkle (MA); Miramar (MIR); Morena (MO); Murray (MUR); Olivenhain (OL); Poway (POW); Ramona (RA); Red Mountain (RD MO); San Dieguito (SN DG); San Vicente (SN VI); Sutherland (SL); Sweetwater (SW); Turner (TR); Upper Otay (UP OT); Wohlford (WF). The black points indicate the three reservoirs we sampled.

Mentions: Reservoirs for water storage have been extensively constructed throughout the arid southwest of North America, and represent the largest area of freshwater ecosystems. In San Diego County, most of freshwater for human use is imported. From 2009 to 2013, the five-year average imported water supplies for San Diego County included 63% from the Colorado River, 20% from the Sacramento and San Joaquin rivers, and the last 17% from local supplies including runoff from seven watersheds, groundwater, and recycled waste water (http://www.sdcwa.org/imported-supplies). Twenty-four major reservoirs in the county (Fig 1) store water for human consumption and are used for recreational activities such as boating and fishing. There are no data on the CO2 budgets of these reservoirs. Additionally, no studies have investigated how the transport of water over great distances and its storage affects the carbon cycle in Southern California. With the enactment of California’s Assembly Bill 32 in 2006, many counties have been taking steps to reduce GHG emissions, including investigating the impacts of reservoirs on CO2 and CH4 [16]. As water demand increases with continued human population growth, resulting in more construction of dams, it is important to understand the impact of creating and maintaining reservoirs on the global carbon cycle.


Seasonal Changes in Plankton Food Web Structure and Carbon Dioxide Flux from Southern California Reservoirs.

Adamczyk EM, Shurin JB - PLoS ONE (2015)

Twenty-four major reservoirs in San Diego County, California, USA http://www.sdcwa.org/san-diego-county-water-sources (http://www.sdcwa.org/reservoirs).Barret (BA); Cuyamaca (CU); Dixon (DI); El Capitan (CAP); Henshaw (HE); Hodges (HO); Jennings (JE); Loveland (LOV); Lower Otay (LO); Maerkle (MA); Miramar (MIR); Morena (MO); Murray (MUR); Olivenhain (OL); Poway (POW); Ramona (RA); Red Mountain (RD MO); San Dieguito (SN DG); San Vicente (SN VI); Sutherland (SL); Sweetwater (SW); Turner (TR); Upper Otay (UP OT); Wohlford (WF). The black points indicate the three reservoirs we sampled.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608793&req=5

pone.0140464.g001: Twenty-four major reservoirs in San Diego County, California, USA http://www.sdcwa.org/san-diego-county-water-sources (http://www.sdcwa.org/reservoirs).Barret (BA); Cuyamaca (CU); Dixon (DI); El Capitan (CAP); Henshaw (HE); Hodges (HO); Jennings (JE); Loveland (LOV); Lower Otay (LO); Maerkle (MA); Miramar (MIR); Morena (MO); Murray (MUR); Olivenhain (OL); Poway (POW); Ramona (RA); Red Mountain (RD MO); San Dieguito (SN DG); San Vicente (SN VI); Sutherland (SL); Sweetwater (SW); Turner (TR); Upper Otay (UP OT); Wohlford (WF). The black points indicate the three reservoirs we sampled.
Mentions: Reservoirs for water storage have been extensively constructed throughout the arid southwest of North America, and represent the largest area of freshwater ecosystems. In San Diego County, most of freshwater for human use is imported. From 2009 to 2013, the five-year average imported water supplies for San Diego County included 63% from the Colorado River, 20% from the Sacramento and San Joaquin rivers, and the last 17% from local supplies including runoff from seven watersheds, groundwater, and recycled waste water (http://www.sdcwa.org/imported-supplies). Twenty-four major reservoirs in the county (Fig 1) store water for human consumption and are used for recreational activities such as boating and fishing. There are no data on the CO2 budgets of these reservoirs. Additionally, no studies have investigated how the transport of water over great distances and its storage affects the carbon cycle in Southern California. With the enactment of California’s Assembly Bill 32 in 2006, many counties have been taking steps to reduce GHG emissions, including investigating the impacts of reservoirs on CO2 and CH4 [16]. As water demand increases with continued human population growth, resulting in more construction of dams, it is important to understand the impact of creating and maintaining reservoirs on the global carbon cycle.

Bottom Line: We sampled three reservoirs in San Diego, California, weekly for one year.We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m(-2) day(-1). pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs.Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Sciences, Section of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, United States of America.

ABSTRACT
Reservoirs around the world contribute to cycling of carbon dioxide (CO2) with the atmosphere, but there is little information on how ecosystem processes determine the absorption or emission of CO2. Reservoirs are the most prevalent freshwater systems in the arid southwest of North America, yet it is unclear whether they sequester or release CO2 and therefore how water impoundment impacts global carbon cycling. We sampled three reservoirs in San Diego, California, weekly for one year. We measured seasonal variation in the abundances of bacteria, phytoplankton, and zooplankton, as well as water chemistry (pH, nutrients, ions, dissolved organic carbon [DOC]), which were used to estimate partial pressure of CO2 (pCO2), and CO2 flux. We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m(-2) day(-1). pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs. Abundances of microbes (bacteria) peaked in the winter along with pCO2, while phytoplankton, nutrients, zooplankton and DOC were all unrelated to pCO2. Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton.

No MeSH data available.