Dataset for: Phosphorus accumulates faster than nitrogen globally in freshwater ecosystems under anthropogenic impacts
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Combined effects of cumulative nutrient inputs and biogeochemical processes that occur in freshwater under anthropogenic eutrophication could lead to myriad shifts in nitrogen (N):phosphorus (P) stoichiometry in global freshwater ecosystems, but this is not yet well-assessed. Here we evaluated the characteristics of N and P stoichiometries in bodies of freshwater and their herbaceous macrophytes across human-impact levels, regions and periods. Freshwater and its macrophytes had higher N and P concentrations and lower N:P ratios in heavily than lightly human-impacted environments, further evidenced by spatiotemporal comparisons across eutrophication gradients. N and P concentrations in freshwater ecosystems were positively correlated and N:P was negatively correlated with population density in China. These results indicate a faster accumulation of P than N in human-impacted freshwater ecosystems, which could have large effects on the trophic webs and biogeochemical cycles of estuaries and coastal areas by freshwater loadings, and reinforce the importance of rehabilitating these ecosystems.Keywords:
Freshwater ecosystem
Partial pressure
Vacuum induction melting
Nitrogen gas
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Freshwater ecosystem
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In order to develop the high nitrogen efficiency Catalpa bungei C.A.Mey clones,an experiment was carried out to observe nitrogen distribution characteristics and nitrogen efficiency of ten Catalpa bungei C.A.Mey clones treated with the high(+N) and low(-N) nitrogen.The results showed that more nitrogen distributed to the underground part(rootleafstem) under the low nitrogen treatment,while situations under the high nitrogen treatment was contrary(leafstemroot).There was no significant difference on nitrogen distribution between clones.Nitrogen efficiency of clones significantly higher under high nitrogen than low nitrogen,but variation degree among clones under low nitrogen was higher than that under high nitrogen.Variation degree of both of nitrogen absorption efficiency and nitrogen utilization efficiency was much higher under low nitrogen.Increasing nitrogen application rate could improve nitrogen absorption efficiency significantly,but declined nitrogen utilization efficiency.Based on the results of correlation analysis,nitrogen absorption efficiency contributed more to the nitrogen efficiency than nitrogen utilization efficiency.Nitrogen efficiency of 2-7 and 015-1 clones were higher than others under both high and low nitrogen treatments.
Absorption efficiency
Nitrogen deficiency
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Nitrogen is a critical nutrient linked to degradation of freshwater and marine ecosystems. The nitrogen inputs to terrestrial ecosys- tems and subsequent loadings to aquatic ecosystems have been doubled and changed the nitrogen cycle as population and hu- man activities increased over the past century. One of the consequences of human alter- nation of the nitrogen cycle is the eutrophication of marine and freshwater ecosystems. We tested if climate variability can change nitrogen loading from terrestrial to aquatic ecosystems. We used stream nitrogen concen- trations from 2,125 sites and climate data from 301 stations from 30 eco-regions across British Columbia, Canada, to test our ob- jective and to compare it with anthropogenic loading of nitrogen in the same regions. We show that elevated air temperature and associated precipitation resulted in increase in nitrogen loading from terrestrial to aquatic ecosystems. Furthermore, inorganic ni- trogen (IN) loading increased more rapidly than organic nitrogen (ON) with increasing air temperature. Each oC increment annu- al air temperature caused a 24% increase in nitrogen loading to aquatic ecosystems and a 22% increase in ratio of IN: ON concen- trations in stream water. We also show that the coastal mountains ecosystems seem to be more vulnerable to temperature induced nitrogen loss than the interior ecosystems. We suggest that cli- mate warming and elevated loading of nitrogen from terrestrial to aquatic ecosystems will have major implications for the quality of water in freshwater and coastal marine ecosystems.
Terrestrial ecosystem
Freshwater ecosystem
Marine ecosystem
Nitrogen Cycle
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Freshwater ecosystem
Marine ecosystem
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Effects of nitrogen application period on nitrogen accumulation,translocation and nitrogen use efficiency were studied.The main results as following: compared with CK,nitrogen application increased NHI and amounts of nitrogen accumulation in plants and grain.The amounts of nitrogen accumulation in ear increased quickly after silking,nitrogen translocation of stem and sheath happened mostly in early filling stage,nitrogen translocation of leaf happened mostly in middle and later filling stage.Nitrogen application made nitrogen physiological efficiency declined 16%,nitrogen fertilizer efficiency was no obvious difference among three treatments.The 60%-70% in total nitrogen accumulation amounts of plants was accumulated from silking to maturing stage,the nitrogen accumulation amounts and nitrogen use efficiency of T4 were highest,compared with T2 and T3,the NUE of T4 heightened 21.8 and 22.8 percent points.
Nitrogen deficiency
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Forty healthy growing laboratory rhesus monkeys were randomly divided into A and B group. According to calcium to phosphorus ratio (1.2:1,1.4:1,1.6:1,1.8:1 and 2.0:1) each group was divided into five groups (A 1 ,A2,A3,A4,A5 and B1 ,B2,B3,B4,B5 respectively), including 2 male and 2 female in each. The level of dietary calcium or phosphorus and calcium to phosphorus ratio were adjusted by CaCO3, CaHPO3and NaH2PO4. The result showed, that no effect of calcium to phosphorus ratio on its utilization in growing laboratory rhesus monkeys were observed in A groups (P0.05). Calcium and phosphorus utilization of B1 group were the highest in B groups (P0.01). The results suggested that the calcium to phosphorus ratio 1.2:1 with phosphorus level 0.89% in dietary was the best choice for calcium and phosphorus utilization in growing laboratory rhesus monkeys.
Phosphorus deficiency
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The relative analyses show that the correlation extents were different between various nitrogen forms and nitrogen absorption contents of maize in Albic soil of east regions of Heilongjiang Province.The N0 value,available nitrogen,hydrolizable nitrogen,amino acid-nitrogen and mineralizable nitrogen had very significant positive relation with nitrogen absorption contents of maize.Also,the total nitrogen,amino sugar nitrogen and ammonium nitrogen had significant positive relation with nitrogen absorption contents of maize.But the unidentified nitrogen,unhydrolizable nitrogen had no relation with the nitrogen adsorption contents of maize.
Nitrogen deficiency
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Nitrogen gas
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Abstract Nitrogen release values obtained by an incubation technique were closely correlated with yield responses of winter wheat to nitrogen on a wide range of soils over four seasons. On soils of low nitrogen status highest yields were obtained from early‐spring applications of nitrogen. On soils of high nitrogen status the highest yields were obtained from latespring applications of nitrogen.
Nitrogen deficiency
Winter wheat
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