| The specific geography of the Antarctic does not protect the region from the negative impacts of human activities.The influence of trace elements on the Antarctic is ubiquitous.Previously,the understanding of trace elements in the Antarctic was limited to lead（Pb）and copper（Cu）elements.Subsequent in-depth investigations have expanded the types of trace elements in the Antarctic,such as Chromium（Cr）,manganese（Mn）,zinc（Zn）and cadmium（Cd）elements.Atmospheric circulation,ocean currents,biological migration,human research and other activities have contributed greatly to the transport of trace elements to the Antarctic region.Abiotic environmental media（fresh and sea water,precipitation,glaciers,soil,etc.）,as well as all processes and phenomena（meteorological,geological,geochemical processes,etc.）associated with changes in individual elements of the environment,play an important role in the transport of trace elements in the Antarctic.In addition,because of the unique structure of the Antarctic ecosystem,relationships between different organisms are important in terms of element transfer.Trace metals in the ocean are closely related to proteins,vitamins and amino acids,which drive the transformation of enzymes and provide part of the energy needed by Marine organisms for life.The Southern Ocean is rich in Marine biological resources,from predominantly algae phytoplankton to predominantly krill zooplankton,composed of various kinds of fish in the middle nutrition level and even the penguins,seals and other senior nutrition level of the Southern Ocean food webs,trace element in maintaining has an indispensable role in the food web and stable operation.Although Euphausia superba is an important food source for most Marine organisms,the ecological role of Euphausia superba is particularly important if there are regional ecosystems in the Southern Ocean that are not entirely dependent on krill,or if the amount of krill in the Southern Ocean is low.According to statistics,there are at least 480 families of 23,350 species of fish in the world,while Antarctic fish account for only 1.3%.The Antarctic fishes are composed of Channichthyidae,Notothenidae,Gadidae,Harpagiferidae,Liparidae,Paralepididae and lantern fish,it is composed of 8 families including Myctophidae and Macrouridae,and has important status and scientific research value in the Marine ecosystem of the Southern Ocean.Among them,the mackerel icefish（Champsocephalus gunnari Lonnberg,1905）is of great ecological and commercial value.The mackerel icefish,belonging to the Channichthyidae,is mainly distributed in the low latitude area of the Antarctic.It is commonly found in the coastal waters of South Georgia Islands,South Shetland Islands,South Orkney Island,Elephant Island and Kerguelen Islands and the surrounding waters.C.gunnari is the most abundant in the Seasonal Pack-Ice Zone.Since 1970,the mackerel icefish has been heavily exploited by the commercial fishery and are the most common by-catch species in the Antarctic krill fishery.Although it has important ecological function and ecological value,the research on it is still limited,especially on trace elements.Limited data on this aspect hampered our understanding of the effects of natural variation and anthropogenic activities on fish species in the primitive region,as well as our ability to assess stocks and manage fisheries for this species.As proposals for the creation of Marine protected areas in Antarctica move forward,strengthening basic research on important fish species is crucial for better conservation of fishery resources.Therefore,this research aimed at determining levels of trace elements in specific tissues of C.gunnari of in the South Georgia and South Orkney Islands,on the basis of biology identification,including body length,body weight,sexual maturity,etc.,and its organizations,this determination,element analysis to determine the level of elements in the organization,analysis of different length of element concentration changes of individual differences,The distribution patterns of different trace elements in different tissues were discussed and regional differences was carried out.The relevant results can provide baseline data for bioaccumulation of elements in white blood ice fish,and enrich the research database of trace elements in C.gunnari,and provide scientific data for China to participate in the establishment of Antarctic Marine protected areas.The main conclusions of this study are as follows:（1）Quantitative analysis of Cu,Pb,Cd and Zn elements in muscle tissue of C.gunnari was carried out.The average contents of four elements were as follows:Zn(56.28±11.21μg g-1 dry weight)>Cu(0.91±0.72μg g-1 dry weight)>Cd(0.26±0.21μg g-1 dry weight)>Pb(0.13±0.05μg g-1 dry weight);except for Zn,varied in a range of2-3 times,and the concentrations of Cd were significantly correlated with the contents of Cu and Pb,and the concentration of Cu was significantly positively correlated with body length.（2）Quantitative analysis of Cu,Pb,Cd and Zn elements in muscle,liver,intestine,gill and skin of C.gunnari was carried out.The average concentration of four elements in each tissue was sorted as follows:Muscle:Zn(56.60±9.94μg g-1 dry weight)>Cu(0.70±0.85μg g-1 dry weight)>Cd(0.12±0.04μg g-1 dry weight)>Pb(0.23±0.18μg g-1 dry weight),skin:Zn(70.40±10.20μg g-1 dry weight)>Cu(1.81±0.62μg g-1 dry weight)>Cd(1.12±0.52μg g-1 dry weight)>Pb(0.46±0.22μg g-1 dry weight),intestines:Zn(65.90±15.20μg g-1 dry weight)>Cu(3.49±0.87μg g-1 dry weight)>Cd(1.13±0.29μg g-1 dry weight)>Pb(0.34±0.24μg g-1 dry weight),liver:Zn(99.80±23.90μg g-1 dry weight)>Cu(2.90±0.66μg g-1 dry weight)>Pb(1.18±0.64μg g-1dry weight)>Cd(0.83±0.38μg g-1 dry weight),gill:Zn(104±13.80μg g-1 dry weight)>Cu(2.32±0.14μg g-1 dry weight)>Cd(0.64±0.41μg g-1 dry weight)>Pb(0.42±0.23μg g-1 dry weight).The concentrations of Zn in the five tissues were significantly higher than those of the other three elements,while the concentrations of Cu,Cd and Pb remained the same order of magnitude.The distribution of elements in organisms was affected by the functional and metabolic differences of tissues in the C.gunnari.The four elements were lowest in muscle,but higher but different levels in the other four tissues.The content of Cd in gills was significantly lower than that in other tissues,but the content of Zn in gills was significantly higher than that in other tissues except intestinal tract.Cu concentrations in the skin are lower than in the gills,intestines and liver,but higher than in the muscles.The concentration of Pb in liver was significantly higher than that in the other four tissues.Different elements have significant correlation in different tissues.（3）The concentration of trace elements of C.gunnari from South Georgia Island is as follows:Zn(55.68±10.58μg g-1 dry weight)>Cu(1.05±0.52μg g-1 dry weight)>Cd(0.28±0.21μg g-1 dry weight)>Pb(0.13±0.06μg g-1 dry weight);The concentration of trace elements of C.gunnari from South Orkney Island was as follows:Zn(121.45±39.96μg g-1 dry weight)>Cu(5.01±1.68μg g-1 dry weight)>Pb(0.97±0.44μg g-1 dry weight)>Cd(0.53±0.23μg g-1 dry weight).The statistical results showed that the contents of four elements in the icefish from South Georgia Island were significantly lower than those from South Orkney Island,and the differences in biological characteristics and geographical location contributed to this result.Because physical and chemical factors such as temperature,salinity,pH and dissolved oxygen all affect the bioavailability of trace elements in the C.gunnari.At the same time,the correlation patterns of the four elements with body length and elements in the two regions were consistent,indicating that the accumulation pattern of elements in the organism is only related to its own regulatory mechanism,and may not be affected by the external environment. |
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