Phosphatase plays an important role in the microbial liberation of phosphorus in soil systems. In this study, alkaline phosphatase activity （APA） was investigated from tundra ornithogenic soil profiles in Antarctica...Phosphatase plays an important role in the microbial liberation of phosphorus in soil systems. In this study, alkaline phosphatase activity （APA） was investigated from tundra ornithogenic soil profiles in Antarctica and Arctic. The organic carbon （TOC）, total nitrogen （TN）, and phosphorus fractions and pH were also analyzed in these soils. The correlation between APA and soil chemical properties is discussed. In almost all the soil profiles, APA showed the same variation patterns. The maximum APA appeared in the surface layers, and decreased with soil depth. The APA ranged from 1.00 ppm to 1 403.5 ppm with an average of approximately 408.3 ppm. The APA showed a significant positive correlation with TOC （r =0.70, p 〈0.001）, TN （r =0.43, p =0.002）, total phosphorus （r =0.39, p 〈0.05）and inorganic phosphorus （r =0.40, p =0.037）, indicating that they were predominant factors affecting APA in the polar tundra soils. In addition, APA showed a significant negative correlation with Cu and Zn concentrations in the soils, indicating that Cu and Zn may inhibit APA. Our results showed that APA could be used as an important indicator for soil fertility in polar tundra ecosystems.展开更多
The Ps. georgianus （Pseudochaenichthys georgianus） were sampled in the summer between 1979 and 2009 at South Georgia Island, and at South Shetland Island. The otoliths ofPs. georgianus contained microincrements simi...The Ps. georgianus （Pseudochaenichthys georgianus） were sampled in the summer between 1979 and 2009 at South Georgia Island, and at South Shetland Island. The otoliths ofPs. georgianus contained microincrements similar to daily increments in the otoliths of fishes from temperate and tropical waters. The estimated age from microincrements was similar to that inferred from the body length distribution and otoliths mass： age （years） = 81.98 × Otolith Mass （g） - 0.483. Ps. georgianus like all Channichthyidae due to their adoption to cold water, attain rapidly large body in accordance with the parameters of the von Bertalanffy growth equation： L∞ （asymptotic length） = 66.1 cm; K （constant related to coefficient of catabolism） = 0.28; to （age of the fish at initial length） = 0.008 year; L0 （length of the fish at initial age） = 0.15 cm. That fast growth rate （despite the difference in hatching periods between regions at South Georgia Island, and at South Shetland Island） were not changed, confirming, that it is established to cold water by natural selection. Changes of the microincrements growth pattern are described that appear to be related to larval, hatching and metamorphosis, and have similar pattern to those ones previewed in C. aceratus （Chaenocephalus aceratus） and C. gunnarii （Champsocephalus gunnarii）. Larvaes and postlarvaes of that species have similar habitats during early life history, which is reflected in similar otoliths morphology. Width of their daily increments is： 0.0018-0.0028 mm for Ps. georgianus, 0.0015-0.0024 mm for C. gunnarii and 0.001-0.0016 mm for C. aceratus. The age and developments periods of South Georgia＇s icefish （common name and the abbreviation = SGI for Ps. georgianus as this species was found only there in the past） estimated from otolith was validated by their different geographical distribution depending on the currents and the presence of their food-krill in them. Postlarvae and early juvenile stages were concentrated at the south-western side of the island shelves deeper than 200 m, where currents are weaker in comparison to surface and where juvenes and small krill prevail. Older and mature fish, over 3 or 4 years old, were numerous on the north-eastern side of the islands shelves in regions of strong vortices that concentrate krill to high densities. As life in the currents needs greater ability to swimming as a large, mature and 4 years old fish had increased their ability to swim up to 4 times growing and developing from inshore larvae. During that, their otoliths become more flattened （up to 3 times） and elongated for better fulfil its functions in the higher swimming speed. However, similar species C. aceratus and C. gunnari have more flattened and elongated otoliths than Ps. georgianus and have larger geographical occurrence from Palmer Archipelago to Kerguelen. The least elongated means the highest otolith, which reflects the highest body of Ps. georgianus, which help this species to stay on the shelf during swimming. High body gives less drifting during swimming in the currents. Evolution of otolith shape is linked with a body shape to decrease resistance and achieve high speed of swimming. During development, Ps. georgianus use different currents and countercurrents to catch different krill stages. System of current is natural environment of life ofPs. georgianus.展开更多
基金supported by the National Natural Science Foundation of China (Grant no.41076124)the KnowledgeInnovation Project of Chinese Academy of Sciences (Grant no.KZCX2-YW-QN510)+1 种基金the Fundamental Research Funds for the Central Universities(Grant no. WK2060190007)the Open Research Foundation of SOA Key Laboratory for Polar Sciences (Grant no.KP2008004)
文摘Phosphatase plays an important role in the microbial liberation of phosphorus in soil systems. In this study, alkaline phosphatase activity （APA） was investigated from tundra ornithogenic soil profiles in Antarctica and Arctic. The organic carbon （TOC）, total nitrogen （TN）, and phosphorus fractions and pH were also analyzed in these soils. The correlation between APA and soil chemical properties is discussed. In almost all the soil profiles, APA showed the same variation patterns. The maximum APA appeared in the surface layers, and decreased with soil depth. The APA ranged from 1.00 ppm to 1 403.5 ppm with an average of approximately 408.3 ppm. The APA showed a significant positive correlation with TOC （r =0.70, p 〈0.001）, TN （r =0.43, p =0.002）, total phosphorus （r =0.39, p 〈0.05）and inorganic phosphorus （r =0.40, p =0.037）, indicating that they were predominant factors affecting APA in the polar tundra soils. In addition, APA showed a significant negative correlation with Cu and Zn concentrations in the soils, indicating that Cu and Zn may inhibit APA. Our results showed that APA could be used as an important indicator for soil fertility in polar tundra ecosystems.
文摘The Ps. georgianus （Pseudochaenichthys georgianus） were sampled in the summer between 1979 and 2009 at South Georgia Island, and at South Shetland Island. The otoliths ofPs. georgianus contained microincrements similar to daily increments in the otoliths of fishes from temperate and tropical waters. The estimated age from microincrements was similar to that inferred from the body length distribution and otoliths mass： age （years） = 81.98 × Otolith Mass （g） - 0.483. Ps. georgianus like all Channichthyidae due to their adoption to cold water, attain rapidly large body in accordance with the parameters of the von Bertalanffy growth equation： L∞ （asymptotic length） = 66.1 cm; K （constant related to coefficient of catabolism） = 0.28; to （age of the fish at initial length） = 0.008 year; L0 （length of the fish at initial age） = 0.15 cm. That fast growth rate （despite the difference in hatching periods between regions at South Georgia Island, and at South Shetland Island） were not changed, confirming, that it is established to cold water by natural selection. Changes of the microincrements growth pattern are described that appear to be related to larval, hatching and metamorphosis, and have similar pattern to those ones previewed in C. aceratus （Chaenocephalus aceratus） and C. gunnarii （Champsocephalus gunnarii）. Larvaes and postlarvaes of that species have similar habitats during early life history, which is reflected in similar otoliths morphology. Width of their daily increments is： 0.0018-0.0028 mm for Ps. georgianus, 0.0015-0.0024 mm for C. gunnarii and 0.001-0.0016 mm for C. aceratus. The age and developments periods of South Georgia＇s icefish （common name and the abbreviation = SGI for Ps. georgianus as this species was found only there in the past） estimated from otolith was validated by their different geographical distribution depending on the currents and the presence of their food-krill in them. Postlarvae and early juvenile stages were concentrated at the south-western side of the island shelves deeper than 200 m, where currents are weaker in comparison to surface and where juvenes and small krill prevail. Older and mature fish, over 3 or 4 years old, were numerous on the north-eastern side of the islands shelves in regions of strong vortices that concentrate krill to high densities. As life in the currents needs greater ability to swimming as a large, mature and 4 years old fish had increased their ability to swim up to 4 times growing and developing from inshore larvae. During that, their otoliths become more flattened （up to 3 times） and elongated for better fulfil its functions in the higher swimming speed. However, similar species C. aceratus and C. gunnari have more flattened and elongated otoliths than Ps. georgianus and have larger geographical occurrence from Palmer Archipelago to Kerguelen. The least elongated means the highest otolith, which reflects the highest body of Ps. georgianus, which help this species to stay on the shelf during swimming. High body gives less drifting during swimming in the currents. Evolution of otolith shape is linked with a body shape to decrease resistance and achieve high speed of swimming. During development, Ps. georgianus use different currents and countercurrents to catch different krill stages. System of current is natural environment of life ofPs. georgianus.
