| As the estuarine wetland,the Yellow River Delta(YRD)is very rare in the world.This wetland has the superior natural environmental conditions,which make it become an important habitat for birds in the world.Gelochelidon nilotica is one of the most common birds in the Yellow River Delta wetland.However,the severe environmental pollution situation in recent years has deeply affected the growth and reproduction of birds.Therefore,the contents of typical heavy metals in the feathers of Gull-billed Tern(adult,sub-adult and fledgling)and the egg shell of Gull-billed Tern with incubating success and failure,the egg shell membrane and contents were measured and contrasted,and the effects of heavy-metal pollution in the wetlands of the YRD on the hatching and reproduction of Gull-billed Tern were discussed.The research results are as follows.(1)The average content of Cd,Cr,Ni,Mn,Pb,Cu and Fe in the feather s of fledglings,adult,and sub-adult of Gull-billed Tern is 0.04,19.04,8.06,20.03,32.03,112.91 and 139.44 mg/kg;0.06,26.69,6.09,38.27,36.8,163.82 a nd 276.07 mg/kg;0.41,46.70,16.54,8.63,54.65,325.94 and 470.48 mg/kg.T herefore,the order of heavy metal content in the feathers of fledglings,adult,and sub-adult of Gull-billed Tern is Fe>Cu>Pb>Mn>Cr>Ni>Cd,Fe>Cu>Mn>P b>Cr>Ni>Cd,Fe>Cu>Pb>Cr>Ni>Mn>Cd.(2)The content of heavy metals in the feathers of the three growth stages of adult birds,sub-adult birds and fledglings is significantly different.The content of heavy metals in the feathers of sub-adult birds is significantly higher than that of the other two growth stages(Except Mn).And the content of heavy metals in the feathers of adult birds is obviously higher than that of fledglings(Except Ni).Therefore,the accumulation of feathers of Gull-billed Tern for heavy metals in the YRD wetland tends to increase in the beginning and then decrease during the growth process;while in the three growth periods,the contents of Fe,Cu and Pb are higher,and the contents of Ni and Cd are lower.Therefore,the enrichment level of Fe,Cu and Pb in the feathers of Gull-billed Tern is relatively high,while the enrichment ability of Ni and Cd is relatively low.(3)No significant correlations were found among the contents of heavy metals in the feather of Gull-billed Tern for different growth periods.In each growth period,significant correlations were showed for some elements,although the content of heavy metals was significantly different.For example,Cd and Ni,Pb and Fe were significantly positively correlated in the feather of young bird(P< 0.05);Mn and Ni,Pb and Cu were significantly positively correlated in the feathers of sub adult birds(P<0.05),Cd and Cr,Cr and Fe,Cd and Fe were extremely significantly positively correlated in the feathers of sub adult birds(P<0.01).Cr and Ni were significantly positively correlated in the feathers of adult birds(P<0.05).There was extremely significant positive correlation between Pb and Cu,Mn and Fe for adult birds(P< 0.01).Therefore,the influence of heavy metals in the YRD wetland on the feather of Gull-billed Tern is obviously different in the different growth periods.The pollution sources of heavy metals in Gull-billed Tern feather are different in each growth period.The influence of Fe and Mn on the content of heavy metals in the feather is not significant,and there is a mutual influence relationship between some heavy metals.(4)The average content of Cr,Ni,Mn,Pb,Cu and Fe in the eggshell of hatching success,hatching failure,content and eggshell membrane of Gull-billed Tern is 27.81,7.76,9.47,96.15,110.35 and 209.78 mg/kg;28.65,8.58,11.95,70.36,222.27 and 302.29 mg/kg;20.28,6.7,10.09,49.85,202.6 and 264.91 mg/kg;395.10,132.91,18.88,247.39,294.40 and 1136.5 mg/kg respectively.Therefore,the order of heavy metal content in the successful hatching of eggshells,hatching failed eggshells,contents and eggshell membranes of Gull-billed Tern is Fe>Cu>Pb>Cr>Mn>Ni,Fe>Cu>Pb>Cr>Mn>Ni,Fe>Cu>Pb>Cr>Mn>Ni and Fe>Cr>Cu>Pb>Ni>Mn.(5)The content of Fe,Cu and Pb in the eggshell of hatching success,hatching failure,content and eggshell membrane of Gull-billed Tern are higher than others,while Ni and Mn are lower.However,significant difference was observed among the contents of heavy metals.In particular,the content of heavy metals in the eggshell membrane is the highest.Therefore,the eggshell membrane has a strong enrichment capacity for heavy metals.In addition,the content of Pb,Cu,Fe in the hatching successful and failed eggshells was significantly different.The content of Cu in the hatched failed eggshells was significantly higher than that in the successful eggshells.Therefore,Cu pollution may be the important reason for the failure of hatching.(6)There was a significant positive correlation(P<0.05)between the contents of Pb and Cu,Mn and Ni(Pb),and a extremely significant positive correlation(P<0.01)between Cr and Ni,Mn,Pb in the eggshell of hatching success of Gull-billed Tern.There was a significant positive correlation(P<0.05)between Cr and Cu,Fe and Pb,Fe and Mn,and a extremely significant positive correlation(P<0.01)between Cr and Ni,Fe and Cr(Ni)in the egg shell of hatching failure.while a significant negative correlation between Fe and Pb,Mn and Cu.a extremely significant negative correlation between Ni and Pb.There was a significant positive correlation(P < 0.05)between Cr and Cu,Ni and Cu,Ni and Cr(Fe)in the egg contents,and a extremely significant positive correlation(P<0.01)between Cr and Ni,while a significant negative correlation between Ni and Pb,Mn and Cu.a extremely significant negative correlation between Ni and Mn.There was a significant positive correlation(P<0.05)between Cu and Pb in the eggshell membrane,and a extremely significant positive correlation(P<0.01)between Cr and Ni,Mn and Fe.Therefore,the selectivity and difference of heavy metal enrichment ability in the eggshell of hatching success,hatching failure,content and eggshell membrane of Gull-billed Tern.The contents of Fe and Mn have significant influence on the enrichment of other heavy metals,and some heavy metals may have interaction mechanism. |
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