Nutrients and photosynthesis pigments were investigated in the western Arctic Ocean during the 3rd Chinese Arctic Research Expedition Cruise in summer 2008. The study area was divided into five provinces using the K- ...Nutrients and photosynthesis pigments were investigated in the western Arctic Ocean during the 3rd Chinese Arctic Research Expedition Cruise in summer 2008. The study area was divided into five provinces using the K- means clustering method based on the physical and chemical characteristics of the sea water, and to discuss the distribution of the phytoplankton community structure in these provinces. CHEMTAX software was performed using HPLC pigments to estimate the contributions of eight algal classes to the total chlorophyll a （TChl a）. The results showed that on the Chukchi Shelf, the Pacific Ocean inflow mainly controlled the Chl a biomass and phytoplankton communities by nutrient concentrations. The high nutrient Anadyr Water and Bering Shelf Water （AnW and BSW） controlled region have high Chl a levels and the diatom dominated community structure. In contrast, in the region occupied by low-nutrient like Alaska Coastal Water （ACW）, the Chl a biomass was low, with pico- and nano-phytoplankton as dominated species, such as prasinophytes, chrysophytes and cryptophytes. However, over the off-shelf, the ice cover condition which would affect the physical and nutrient concentrations of the water masses, in consequence had a greater impact on the phytoplankton community structure. Diatom dominated in ice cover region and its contribution to Chl a biomass was up to 75%. In the region dose to the Mendeleev Abyssal Plain （MAP）, controlled by sea-ice melt water with relatively high salinity （MW-HS）, higher nutrient and Chl a concentrations were found and the phytoplankton was dominated by pico- and nano-algae, while the diatom abundance reduced to 33%. In the southern Canada Basin, an ice-free basin （IfB） with the lowest nutrient concentrations and most freshened surface water, low Chl a biomass was a consequence of low nutrients. The ice retreating and a prolonged period of open ocean may not be beneficial to the carbon export efficiency due to reducing the Chl a biomass or intriguing smaller size algae growth.展开更多
We examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove（GWC） and Ardley Cove（AC）, near the Chinese Antarctic Great Wall Station, using measurements taken ...We examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove（GWC） and Ardley Cove（AC）, near the Chinese Antarctic Great Wall Station, using measurements taken in January 2013 and other recent data. Nutrient concentrations were high, with phosphate concentrations of 1.94（GWC） and 1.96（AC） μmol·L-1, DIN（dissolved inorganic nitrogen） concentrations of 26.36（GWC） and 25.94（AC） μmol·L-1 and silicate concentrations of 78.6（GWC） and 79.3（AC） μmol·L-1. However, average concentrations of chlorophyll a were low（1.29 μg·L-1, GWC and 1.08 μg·L-1, AC）, indicating that this region is a high-nutrient and low-chlorophyll（HNLC） area. Nutrient concentrations of freshwater（stream and snowmelt） discharge into GWC and AC in the austral summer are low, meaning freshwater discharge dilutes the nutrient concentrations in the two coves. Strong intrusion of nutrient-rich water from the Bransfield Current in the south was the main source of nutrients in GWC and AC. Low water temperature and strong wind-induced turbulence and instability in the upper layers of the water column were the two main factors that caused the low phytoplankton biomass during the austral summer.展开更多
Concentrations of chlorophyll-a（Chl-a）, particulate organic carbon（POC） and its stable carbon isotope composition（δ13C） were analyzed to investigate the biogeochemical characteristics and sources of POC in Grea...Concentrations of chlorophyll-a（Chl-a）, particulate organic carbon（POC） and its stable carbon isotope composition（δ13C） were analyzed to investigate the biogeochemical characteristics and sources of POC in Great Wall Cove（GWC） and Ardley Cove（AC） during the austral summer. POC concentrations ranged from 50.51 to 115.41 μg·L^-1（mean±1 standard deviation： 77.69±17.27 μg·L^-1） in GWC and from 63.42 to 101.79 μg·L^-1（82.67±11.83 μg·L^-1） in AC. The POC δ13C ranged from-30.83‰ to-26.12‰（-27.40‰±0.96‰） in GWC and from-28.21‰ to-26.65‰（-27.45‰±0.47‰） in AC. The temperature and salinity results showed distinct runoff signals in both GWC and AC, although the δ13C data and POC distribution indicate a negligible influence of land sources upon POC. The δ13C values suggest that POC is of predominantly marine origin. The POC/Chl-a ratio and the relationship between POC and Chl-a indicate that phytoplankton, organic detritus and heterotrophic organisms are significant contributors to POC in GWC and AC.展开更多
基金The National Natural Science Foundation of China under contract Nos 41276198,41506222 and 41406217Chinese Polar Environment Comprehensive Investigation and Assessment Programs under contract Nos Chinare-03-04 and Chinare-04-03+2 种基金Chinese Polar Science Strategy Research Foundation under contract No.20120104the Sino-German Joint Project of"Natural variability of Arctic sea ice and its significance for global climate change and organic carbon cycle"the Foundation from the China Scholarship Council under contract No.201404180012
文摘Nutrients and photosynthesis pigments were investigated in the western Arctic Ocean during the 3rd Chinese Arctic Research Expedition Cruise in summer 2008. The study area was divided into five provinces using the K- means clustering method based on the physical and chemical characteristics of the sea water, and to discuss the distribution of the phytoplankton community structure in these provinces. CHEMTAX software was performed using HPLC pigments to estimate the contributions of eight algal classes to the total chlorophyll a （TChl a）. The results showed that on the Chukchi Shelf, the Pacific Ocean inflow mainly controlled the Chl a biomass and phytoplankton communities by nutrient concentrations. The high nutrient Anadyr Water and Bering Shelf Water （AnW and BSW） controlled region have high Chl a levels and the diatom dominated community structure. In contrast, in the region occupied by low-nutrient like Alaska Coastal Water （ACW）, the Chl a biomass was low, with pico- and nano-phytoplankton as dominated species, such as prasinophytes, chrysophytes and cryptophytes. However, over the off-shelf, the ice cover condition which would affect the physical and nutrient concentrations of the water masses, in consequence had a greater impact on the phytoplankton community structure. Diatom dominated in ice cover region and its contribution to Chl a biomass was up to 75%. In the region dose to the Mendeleev Abyssal Plain （MAP）, controlled by sea-ice melt water with relatively high salinity （MW-HS）, higher nutrient and Chl a concentrations were found and the phytoplankton was dominated by pico- and nano-algae, while the diatom abundance reduced to 33%. In the southern Canada Basin, an ice-free basin （IfB） with the lowest nutrient concentrations and most freshened surface water, low Chl a biomass was a consequence of low nutrients. The ice retreating and a prolonged period of open ocean may not be beneficial to the carbon export efficiency due to reducing the Chl a biomass or intriguing smaller size algae growth.
基金supported by the Chinese Polar Environmental Comprehensive Investigation & Assessment Programs (Grant nos. CHINARE 2014-04-01-07, CHINARE 2014-02-01-05)the Chinese Polar Science Strategy Research Foundation (Grant no. 20120104)
文摘We examined the influences upon nutrient, temperature, salinity and chlorophyll a distributions in Great Wall Cove（GWC） and Ardley Cove（AC）, near the Chinese Antarctic Great Wall Station, using measurements taken in January 2013 and other recent data. Nutrient concentrations were high, with phosphate concentrations of 1.94（GWC） and 1.96（AC） μmol·L-1, DIN（dissolved inorganic nitrogen） concentrations of 26.36（GWC） and 25.94（AC） μmol·L-1 and silicate concentrations of 78.6（GWC） and 79.3（AC） μmol·L-1. However, average concentrations of chlorophyll a were low（1.29 μg·L-1, GWC and 1.08 μg·L-1, AC）, indicating that this region is a high-nutrient and low-chlorophyll（HNLC） area. Nutrient concentrations of freshwater（stream and snowmelt） discharge into GWC and AC in the austral summer are low, meaning freshwater discharge dilutes the nutrient concentrations in the two coves. Strong intrusion of nutrient-rich water from the Bransfield Current in the south was the main source of nutrients in GWC and AC. Low water temperature and strong wind-induced turbulence and instability in the upper layers of the water column were the two main factors that caused the low phytoplankton biomass during the austral summer.
基金supported by the Chinese Polar Environmental Comprehensive Investigation & Assessment Programs (Grant nos. CHINARE 2014-04-01-07, CHINARE 2014-02-01-05)the National Natural Science Foundation of China (Grant nos. 41276198, 41076135)Chinese Polar Science Strategy Research Foundation (Grant no. 20120104)
文摘Concentrations of chlorophyll-a（Chl-a）, particulate organic carbon（POC） and its stable carbon isotope composition（δ13C） were analyzed to investigate the biogeochemical characteristics and sources of POC in Great Wall Cove（GWC） and Ardley Cove（AC） during the austral summer. POC concentrations ranged from 50.51 to 115.41 μg·L^-1（mean±1 standard deviation： 77.69±17.27 μg·L^-1） in GWC and from 63.42 to 101.79 μg·L^-1（82.67±11.83 μg·L^-1） in AC. The POC δ13C ranged from-30.83‰ to-26.12‰（-27.40‰±0.96‰） in GWC and from-28.21‰ to-26.65‰（-27.45‰±0.47‰） in AC. The temperature and salinity results showed distinct runoff signals in both GWC and AC, although the δ13C data and POC distribution indicate a negligible influence of land sources upon POC. The δ13C values suggest that POC is of predominantly marine origin. The POC/Chl-a ratio and the relationship between POC and Chl-a indicate that phytoplankton, organic detritus and heterotrophic organisms are significant contributors to POC in GWC and AC.
