This work was funded, in part, by the Great Lakes Fishery Commission and the Annis Water Resources Institute. Use of trade, product, or firm names does not imply endorsement by the U. S. Government. This article is Contribution 1867 of the U. S. Geological Survey Great Lakes Science Center.

1 실험실 실험 <ol><li> 먹이 물고기를 구합니다 실험 기간 동안 포식자 물고기에 공급한다. 바람직하게는 이러한 먹이 물고기는 현장, 냉동에서 캡처, 약 -30 ° C에서 보관해야합니다. 먹이 물고기에 대한 잠재적 인 소스로 상업 낚시 작업을 고려하십시오. </li><li> 실험실 탱크에 포식자 물고기를 소개 실험에 사용한다. 15 포식자 물고기까지 870-L의 각 탱크에 도입되었으며, 30 포식자 물고기까지 이전의 연구 (16, 18)에서 2380-L 탱크에 각각 도입되었다. </li><li> 선택한 먹이 물고기의 다이어트 포식자 물고기를 적응. 적응되면, 포식자 물고기는 실험을 시작하기 전에 1-3개월이 다이어트에 남아 있어야합니다. </li><li> 무작위로 먹이 물고기의 배치에서 10-20 복합 샘플을 선택하여 먹이 물고기의 샘플을 따로 설정합니다. 복합 시료 물고기의 먹이의 수 먹이의 크기에 따라 3 ~ 100의 수물고기입니다. 각 복합 샘플은 냉동 팩에 넣어 약 -30 ° C에서 보관을 두 번해야한다. </li><li> 각 탱크에 물고기 30-50%을 희생하여 실험을 시작합니다. <ol><li> , 물고기를 안락사 큰 플라스틱 용기에 물 45 L로 Finquel의 8g을 혼합 한 후 Finquel 용액으로 용기에 물고기를 배치합니다. </li><li> 일단 안락사, 처리 시간까지 약 -30 ° C에서 가방, 두 번 가방, 저장에 한 탱크에서 희생 된 물고기를 모두 넣습니다. </li><li> 각 탱크 내에 남아있는 물고기의 각각의 무게를 측정하고, 가중치를 기록; 마취는 가능성이 무게를 수행 할 필요합니다. </li><li> , 물고기를 마취 큰 플라스틱 용기에 물 45 L로 Finquel의 4.6 g을 혼합 한 다음 Finquel 용액으로 용기에 물고기를 배치합니다. </li><li> 물고기를 계량하기 전에 적용하려면 마취에 대한 몇 분 정도 기다립니다. </li></ol></li><li> 각 실험 일에, 해동적절한 먹이 물고기의 양, 그리고 약 1 5g에 무게 조각으로 먹이 물고기를 잘라. 다음, 각 탱크에 배치되는 먹이 물고기의 양을 달아 각각의 탱크에 먹이 물고기 조각을 드롭하고 약 1 시간이 공급하는 포식자 물고기를 할 수 있습니다. 그런 다음, 모든 음식을 먹지 제거 약 20 분간 자연 건조 식품을하도록 한 다음 각 탱크에 먹다 남은 음식을 무게. 탱크에 넣고 음식의 양은 매일 탱크마다 먹지 음식의 양을 기록한다. 주 : 하나의 수유 기간 매일 18시 소모하는 것처럼 대표 실험, 호수 송어가 많은 음식으로 공급 하였다. 그러나, 포식자 물고기는 고정 식량 16, 19에 배치 될 수있다. </li><li> 각 탱크에 남은 포식자 물고기 모두 희생하여 실험을 종료. , 물고기를 안락사 큰 플라스틱 용기에 물 45 L로 Finquel의 8g을 혼합 한 후 Finquel 용액으로 용기에 물고기를 배치합니다. 기록 t희생 된 물고기의 각 그는 무게. 신뢰할 수있는 결과를 위해, 실험은 적어도 130일 대해 바람직하게는 최소 100 일 동안 실행한다. 처리 시간이 될 때까지 약 -30 ° C에 하나의 가방, 두 번 가방, 저장에 탱크에서 물고기를 모두 넣습니다. </li></ol> 2 물고기의 균질화 <ol><li> 포식자 물고기 및 / 또는 해동을위한 먹이 물고기 복합 세트를 선택합니다. 복합 부분적으로 해동 할 수 있습니다. 각 복합 균질화 0.5 시간 일에 필요할 수 있습니다. </li><li> 적합한 크기의 블렌더를 사용하여, 각 복합 재료의 균질화. 각 복합 들어, 세척, 아세톤 세척이라는 라벨을 병에 균질 (50~1백g) 샘플을 배치합니다. 그런 다음 항아리 모자와 처리 시간이 될 때까지 약 -30 ° C에서 항아리를 저장합니다. </li><li> 물고기를 균질화하는 데 사용되는 모든 장비를 세척 한 다음 제대로 샘플 사이의 증류수와 메탄올로 씻어냅니다. </li></ol> 3 추출 <ol><li> 20.0 g의 무게를의 200 ㎖의 비이커에 물고기 균질 조직을 해동. </li><li> 황산나트륨 약 40g을 넣고 주걱으로 잘 섞는다. </li><li> 추출물 20 겨 / ㎖의 최종 농도를 산출 농도 동족체 30, 61, 161, 및 166를 포함하는 대리 스파이크 스파이크 액을 합한다. </li><li> 매 20 분을 혼합하면서 샘플을 실온에서 건조하도록 허용합니다. </li><li> 샘플이 샘플 추출을위한 준비가되어있는 시점에서 마른 모래의 일관성을 도달 할 수 있습니다. </li><li> 테프론 종기 칩, 속 슬렛, 콘덴서를 포함하는 500 ㎖의 플라스크에 속 슬렛 추출 장치를 설정합니다. </li><li> 거친 프릿 디스크 바닥이나 종이 골무와 유리 골 무에 건어물 혼합물을 추가합니다. </li><li> 샘플 사용을 비커에 50 % 헥산과 50 %의 디클로로 메탄 150 mL를 넣고 주걱 비이커 벽을 긁어 동안 교반 하였다. </li><li> 속 슬렛을 통해에 사이클에 부착 된 플라스크 속 슬렛의 상단에 용매를 전송하고 그것을 허용플라스크. </li><li> 다시 150 mL를 두 번 반복합니다. </li><li> 가열 소자 상에 부착 된 플라스크에 속 슬렛를 놓고 콘덴서를 연결합니다. </li><li> 가열 소자를 켜고 부드러운 종기 용매를 가지고, 다음 16 시간 차가운 물이 콘덴서에 공급되어 있는지 확인하고 최소 압축을 풉니 다. </li><li> 용매를 식힌 다음 샘플 플라스크의 물을 포함하고 있는지 확인합니다. 물을 함유하는 플라스크를 들어 황산나트륨을 추가하고 물을 황산 나트륨에 의해 흡수 될 때까지 소용돌이 친다. </li><li> 질소 샘플 집중 또는 온수 욕조가있는 Kaderna 덴마크어 (KD) 유리 설치 프로그램을 사용하여 샘​​플을 집중. </li><li> 시료 2 이하 ㎖를 증발하고 5 ㎖의 메스 플라스크에 사용될 유리로부터 샘플을 전송할 헥산 작은 세정액을 사용하여 5 ㎖의 최종 부피로 나오게. </li><li> 10 ㎖의 유리 병에 전송하고 샘플 정보와 함께 레이블을 붙입니다. </li></ol><ol><li> 활성화 실리카 겔 100 g의 진한 황산 44g을 첨가하여 산성화시킨 실리카 겔을 준비한다. </li><li> 하단 유리솜의 작은 플러그를 함유하는 작은 크로마토 그래피 컬럼으로 산성화시키고 실리카 겔 10g을 추가한다. </li><li> 헥산 10 ㎖로 컬럼을 미리 세척 한 후, 컬럼에 시료 추출물 1 ㎖를 추가합니다. </li><li> 헥산 20 ㎖로 칼럼을 용출하고, 20 ㎖의 테이퍼 유리관에 모은다. </li><li> 질소 기류하에 질소 증발기 (N-VAP) 장치에 유리 튜브를 삽입하고 뜨거운 물에 침지. </li><li> 미만 1 ml의 증발하지만 건조하지. </li><li> N-VAP 장치에서 제거하고 헥산의 작은 세탁으로 1 mL 용량 플라스크에 전송합니다. </li><li> 1.8 ml의 오토 샘플러 바이알 샘플 정보로 표지에 전송합니다. </li><li> 유리 병에 내부 표준의 4 μl를 스파이크. 샘플은 지금 분석을위한 준비가되어 있습니다. </li></ol> 5 애널가스 크로마토 그래피에 의한 ysis은 - 질량 분석 네거티브 화학 이온화를 사용하여 <ol><li> 계측기를 교정 표준을 사용하여 표준이 잘​​ 분리 이성체의 그룹으로 구성된 혼합물에서 사용할 수 있습니다. 믹스 1-5 거의 Arochlors 1016, 1221, 1232, 1242, 1248, 1254에서 발견 이성체 모두로 구성하고, 1260 믹스 1은 멀티 레벨 교정 믹스로서 사용되며, 시스템의 선형성은 적어도 제조함으로써 확인된다 이 100 ng를 / ㎖ 사이 농도의 오 보정 레벨. 믹스 2-5은 각 동족체에 대한 단일 지점 교정으로 사용됩니다. </li><li> 반응물 가스 등의 캐리어 가스 (1 ㎖ / 분) 및 메탄 등의 수소와 네거티브 화학 이온화 모드에서 질량 분석 시스템 - 크로마토 그래피를 설정. </li><li> 분리를위한 0.25 μm의 막 두께에 DB-XLB로 코팅 된 융합 실리카, 캐 필러 리 컬럼 (0.25 mm 내경 × 60m)를 사용합니다. 26 다음 25 ° C / 분의 60에서 212 ° C에 프로그램 오븐 온도,0 ° 1 ° C / 분 C, 다음 4 분의 최종 대기 시간, 4 ° C / 분에서 280 ° C까지. 인젝터 및 전송 라인 온도는 280 ° C로 설정해야합니다. 비분 할 분사 모드를 이용하여 시료 1-2 μl를 주입한다. </li><li> 13 C 표지 decachlorobiphenyl를 사용하여 내부 표준 방법에 의해 모든 표준 및 샘플을 분석 할 수 있습니다. </li><li> 두번째 소스 표준 및 Aroclors 1242 및 1260을 실행하여 초기 교정에 대한 검사를 수행 한 다음이 검사 과정에서 관찰 된 양의 Aroclor의 동족체에 대한 예측 값을 비교. </li><li> 모든 샘플의 초기 교정 절차가 성공적으로 수행되면, 완전한 분석. 교정 초기 캘리브레이션으로부터 교정의 혼합물 중 하나를 사용하여 매 10 샘플 검사 실행. </li></ol> 순 영양 전송 효율의 6 계산 <ol><li> 각 조합에 대해 O, γ, 그물 영양 전사 효율을 계산다음 식을 이용하여 F 탱크와 PCB의 동족체 : <img alt="식 (1)" fo:content-width="2in" src="/files/ftp_upload/51496/51496eq1.jpg" /> [PCB 수 f] 실험 끝에 탱크 포식자 물고기의 평균 PCB의 동족체 농도이고, W의 f는, 실험의 끝에 탱크 포식자 물고기의 평균 중량이다 [PCB I] 전 실험의 시작에서 포식자 물고기의 평균 중량이고, 섭취 PCB의 동족체의 양의 중량을 지칭 W 실험의 시작에서 탱크 포식자 물고기의 평균 PCB의 동족체 농도이고, PCB 동족체는 실험 과정 동안 탱크 내의 각 송어로 평균적으로 섭취. </li><li> 탱크 지속에 포식자 물고기 당 먹을 먹이 물고기의 평균 양 (무게)에 의해 먹이 물고기 복합에서 PCB의 동종의 평균 농도를 곱하여 상기 식의 분모를 계산실험의 전체 과정을 보내고. </li></ol>

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P., DeSorcie, T. J., Stedman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ontogenic+and+spatial+patterns+in+diet+and+growth+of+lake+trout+in+Lake+Michigan.">Ontogenic and spatial patterns in diet and growth of lake trout in Lake Michigan.</a> Transactions of the American Fisheries Society. 127 (2), 236-252 (1998).</li><li>Paterson, G., Whittle, D. M., Drouillard, K. G., Haffner, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Declining+lake+trout+(Salvelinus+namaycush)+energy+density:+are+there+too+many+salmonid+predators+in+the+Great+Lakes?.">Declining lake trout (Salvelinus namaycush) energy density: are there too many salmonid predators in the Great Lakes?.</a> Canadian Journal of Fisheries and Aquatic Sciences. 66 (6), 919-932 (2009).</li><li>Madenjian, C. P., O&#8217;Connor, D. V., Nortrup, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+approach+toward+evaluation+of+fish+bioenergetics+models.">A new approach toward evaluation of fish bioenergetics models.</a> Canadian Journal of Fisheries and Aquatic Sciences. 57 (5), 1025-1032 (2000).</li><li>Madenjian, C. P., Pothoven, S. A., Kao, Y. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reevaluation+of+lake+trout+and+lake+whitefish+bioenergetics+models.">Reevaluation of lake trout and lake whitefish bioenergetics models.</a> Journal of Great Lakes Research. 39 (2), 358-364 (2013).</li><li>Madenjian, C. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+a+lake+whitefish+bioenergetics+model.">Evaluation of a lake whitefish bioenergetics model.</a> Transactions of the American Fisheries Society. 135 (1), 61-75 (2006).</li><li>Madenjian, C. P., O&#8217;Connor, D. V., Chernyak, S. M., Rediske, R. R., O&#8217;Keefe, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+a+chinook+salmon+(Oncorhynchus+tshawytscha)+bioenergetics+model.">Evaluation of a chinook salmon (Oncorhynchus tshawytscha) bioenergetics model.</a> Canadian Journal of Fisheries and Aquatic Sciences. 61 (4), 627-635 (2004).</li><li>Madenjian, C. P., David, S. R., Rediske, R. R., O&#8217;Keefe, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Net+trophic+transfer+efficiencies+of+polychlorinated+biphenyl+congeners+to+lake+trout+(Salvelinus+namaycush)+from+its+prey.">Net trophic transfer efficiencies of polychlorinated biphenyl congeners to lake trout (Salvelinus namaycush) from its prey.</a> Environmental Toxicology and Chemistry. 31 (12), 2821-2827 (2012).</li><li>Madenjian, C. P., O'Connor, D. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+evaluation+of+a+lake+trout+bioenergetics+model.">Laboratory evaluation of a lake trout bioenergetics model.</a> Transactions of the American Fisheries Society. 128 (5), 802-814 (1999).</li><li>Ballschmiter, K., Bacher, R., Mennel, A., Fischer, R., Riehle, U., Swerev, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+determination+of+chlorinated+biphenyls,+chlorinated+dibenzodioxins,+and+chlorinated+dibenzofurans+by+GC-MS.">The determination of chlorinated biphenyls, chlorinated dibenzodioxins, and chlorinated dibenzofurans by GC-MS.</a> HRC Journal of High Resolution Chromatography. 15 (4), 260-270 (1992).</li><li>Madenjian, C. P., David, S. R., Pothoven, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+activity+and+energy+budget+balancing+algorithm+on+laboratory+performance+of+a+fish+bioenergetics+model.">Effects of activity and energy budget balancing algorithm on laboratory performance of a fish bioenergetics model.</a> Transactions of the American Fisheries Society. 141 (5), 1328-1337 (2012).</li><li>Lieb, A. J., Bills, D. D., Sinnhuber, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accumulation+of+dietary+polychlorinated+biphenyls+(Aroclor+1254)+by+rainbow+trout.">Accumulation of dietary polychlorinated biphenyls (Aroclor 1254) by rainbow trout.</a> Journal of Agricultural and Food Chemistry. 22 (4), 638-642 (1974).</li><li>Niimi, A. J., Oliver, B. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+half-lives+of+polychlorinated+biphenyl+(PCB)+congeners+in+whole+fish+and+muscle+of+rainbow+trout+(Salmo+gairdneri).">Biological half-lives of polychlorinated biphenyl (PCB) congeners in whole fish and muscle of rainbow trout (Salmo gairdneri).</a> Canadian Journal of Fisheries and Aquatic Sciences. 40 (9), 1388-1394 (1983).</li><li>Gobas, F. A. P. C., Wilcockson, J. B., Russell, R. W., Haffner, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+biomagnification+in+fish+under+laboratory+and+field+conditions.">Mechanism of biomagnification in fish under laboratory and field conditions.</a> Environmental Science and Technology. 33 (1), 133-141 (1999).</li><li>Dmitrovic, J., Chan, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+polychlorinated+biphenyl+congeners+in+human+milk+by+gas+chromatography+&#8211;+negative+chemical+ionization+mass+spectrometry+after+sample+clean-up+by+solid-phase+extraction.">Determination of polychlorinated biphenyl congeners in human milk by gas chromatography &#8211; negative chemical ionization mass spectrometry after sample clean-up by solid-phase extraction.</a> Journal of Chromatography B. 778 (1-2), 147-155 (2002).</li><li>Zorn, M. E., Gibbons, R. D., Sonzogni, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Weighted+least-squares+approach+to+calculating+limits+of+detection+and+quantification+by+modeling+variability+as+a+function+of+concentration.">Weighted least-squares approach to calculating limits of detection and quantification by modeling variability as a function of concentration.</a> Analytical Chemistry. 69 (15), 3069-3075 (1997).</li></ol>

γ의 가장 정확한 추정치를 들어, 정확하게 실험자의 실험 과정에서 탱크 및 탱크의 각각에 먹지 음식의 양에 각각 배치 된 음식의 양 모두를 추적 할 수 있어야한다. 이를 달성하기 위해, 실험자는 탱크로부터 먹지 식품을 모두 제거하고 무게를 정확하게 판별 할 수 있어야한다. 실제로 포식자 물고기가 먹은 음식의 정확한 추적뿐만 아니라, γ의 정확한 추정은 실험의 충분한 기간에 따라 달라질 ...

Of all of the factors affecting the rate at which fish accumulate contaminants, the efficiency with which fish retain contaminants from the food that they eat is one of the most important1-3. Risk assessment models have been developed to predict future risks to both people and wildlife eating contaminated fish under various scenarios of environmental contamination, and the reliability of these predictions critically depends on the accuracy of the estimates of the efficiency at which fish retain contaminants from their food4.
The efficiency with which the contaminant in the food ingested by the predator is transported through the gut wall is known as gross trophic transfer efficiency5. A portion of the quantity of the contaminant transported through the gut wall of the predator may eventually be lost through depuration and/or metabolic transformation. The efficiency with which the contaminant in the food ingested by the predator is retained by the predator, including any losses due to elimination and metabolic transformation, is known as net trophic transfer efficiency6.
Gross trophic transfer efficiency of organic contaminants to fish from their prey appears to vary with the contaminant&#8217;s chemical properties, including lipid affiliation as measured by the octanol-water partition coefficient, Kow3,7. According to an empirical relationship developed by Thomann3, gross trophic transfer efficiency is relatively high when log Kow is equal to a value between 5 and 6. Gross trophic transfer efficiency declines exponentially at a rate of 50% per unit of log Kow as log Kow increases from 6 to 10, according to the Thomann3 relationship.
Nevertheless, the gross and net trophic transfer efficiencies of polychlorinated biphenyl (PCB) congeners to fish from their prey do not appear to follow the Thomann3 relationship in most cases. Although the trophic transfer efficiencies of PCB congeners to lake whitefish (Coregonus clupeaformis) from its food followed the relationship proposed by Thomann8, trophic transfer efficiencies of PCB congeners were either just weakly related or not related at all to log Kow for Atlantic salmon (Salmo salar)9, rainbow trout (Oncorhynchus mykiss)10, coho salmon (Oncorhynchus kisutch)11, and northern pike (Esox lucius)11.
The overall goal of this study was to present a laboratory technique for estimating the net trophic transfer efficiencies of PCB congeners to a piscivorous fish from its prey. Lake trout (Salvelinus namaycush) was chosen as the piscivorous fish for our experiment because lake trout are relatively easy to maintain in laboratory tanks. Bloater (Coregonus hoyi) was selected as the prey fish to be fed to the lake trout because bloater is eaten by lake trout in its natural setting12. In addition, we determined whether the net trophic transfer efficiencies for lake trout estimated from our laboratory experiment followed the Thomann3 relationship. We also determined whether the degree of activity by the lake trout had a significant effect on net trophic transfer efficiency (&#947;) of the PCB congeners. Activity by lake trout in the Laurentian Great Lakes is believed to have recently increased because changes in the food webs have caused lake trout to allocate more energy toward searching for food13. Lake trout were forced to exercise in one set of tanks by subjecting these lake trout to relatively high flow rates, whereas the other lake trout were permitted to remain relatively inactive by subjecting them to relatively low flow rates. Finally, the specific details of our laboratory procedure that need to be carefully followed to ensure the highest degree of accuracy in the &#947; estimates and to make the laboratory results applicable to the field are discussed, as well as future directions for research building on our laboratory technique. Net trophic transfer efficiency can be estimated both in the laboratory and in the field, and advantages and disadvantages are associated with both approaches. Accuracy in the estimate of &#947; depends on the accuracy of the estimate of food consumption. The amount of food eaten by fish in the laboratory can be accurately determined when proper protocols are followed, whereas the amount of food eaten by fish in the field is typically estimated via bioenergetics modeling. Use of bioenergetics modeling to derive the amount of food eaten has the potential to introduce a substantial amount of uncertainty into the estimates of food consumption. Fish bioenergetics models have been shown to estimate food consumption with no detectable bias for the case of lake trout14,15, but considerable bias in bioenergetics model estimates of food consumption has been detected for the case of lake whitefish15,16. On the other hand, estimates of net trophic transfer efficiency estimated in the laboratory may not be applicable to the field due to a difference in feeding rates between the laboratory and the field17. Evidence from both the laboratory and the field suggest that feeding rate can influence &#947;14,17.
The methodology used in the present study for estimating &#947; in the laboratory is applicable to situations where the predator fish is fed prey fish, and the amount of prey fish eaten by the predator can be accurately tracked. To accomplish this, the experimenter must weigh all of the food before placement in the tank; and the experimenter must be able to remove all of the uneaten food from the tank, and then weigh the uneaten food. In addition, an adequate suite of mixers and blenders should be available to obtain a sufficient degree of homogenization of the samples of both predator and prey fish. Finally, the gas chromatography &#8211; mass spectrometry instrumentation used to determine the PCB congener concentrations must be capable of detecting and quantifying individual PCB congeners at relatively low concentrations.

<table border="0" cellpadding="0" cellspacing="0" width="632">
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			<td height="21" style="height:21px;width:259px;">Name&#160;</td>
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			<td style="width:119px;">Catalog Number</td>
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			<td style="width:87px;">Cambridge Isotope Laboratories</td>
			<td style="width:119px;">EC-1410-1.2</td>
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</table>

laboratory estimation of net trophic transfer efficiencies of pcb congeners to lake trout (salvelinus namaycush) from its prey

먹이에서 물고기를 먹는 물고기 폴리 염화 비 페닐 (PCB) 이성체의 순 영양 전달 효율 (γ)의 실험실 추정하는 기술은 여기에 설명되어 있습니다. 135 일 실험실 실험 동안, 우리는 팔 실험실 탱크에 보관 부풀어 오른 송어 (Salvelinus의 namaycush)에 미시간 호수에서 잡은했다 (Coregonus hoyi)를 공급. 부풀어 오른 호수 송어 자연 먹이입니다. 탱크 사에서, 비교적 높은 유속은 낮은 유속이 다른 네 개의 탱크에 사용 된 반면, 낮은 송어 활동을 허용, 송어 의해 비교적 높은 활성을 확인하는 데 사용 하였다. 탱크 탱크 별 기준으로, 실험 하루에 송어 먹게 음식의 양을 기록 하였다. 각 송어은 실험의 시작과 끝에서 칭량 하였다. 팔 각 탱크에서 4 구에 송어은 실험의 시작에서 희생하고, 각 탱크에 남아있는 모든 10 송어는 euthan 하였다이었다실험의 끝에 집중식. 우리의 실험 끝에 송어에서, 실험의 개시시 송어 75 PCB의 이성체의 농도를 측정하고, 실험에 bloaters 동안 송어로 공급. 이러한 측정에 기초하여, γ는 팔 각 탱크의 PCB (75)의 동족체들 각각에 대해 계산 하였다. γ 활성 및 비활성 호수 송어 75 PCB의 동족체 각각에 대해 계산되었다 의미한다. 실험 8 개의 탱크에 복제 되었기 때문에,에 대한 표준 오차는 γ 추정 할 수 의미한다. 이런 유형의 실험 결과는 환경 오염의 다양한 시나리오에 따라 오염 된 물고기를 먹는 인간과 야생 동물에 대한 미래의 위험을 예측하는 위험 평가 모델에 유용하다.

초기 호수 송어 최종 호수 송어는 무게가 853에서 1천5백66그램 (표 1)였다 의미하는 동안 무게가 694-907g 원거리 의미로 호수 송어, 실험 기간 동안 성장의 상당한 양을 보여 주었다. 135 일간의 실험 과정에서 호수 송어에 의해 소비되는 음식의 평균 금액은 641에서 2천6백49g였다. 평균 PCB 동종 농도가 원거리로 평균 PCB 동종 농도가 0.03에서 원거리 동안 호수 송어에서 PCB의 동족체 농도 평?...

Watch this Scientific Journal Video about Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey at JoVE.com

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

먹이에서 물고기를 먹는 물고기 폴리 염화 비 페닐 (PCB) 이성체의 순 영양 전달 효율의 실험실 추정하는 기술이 제시된다. 필드로 실험 결과의 적용 가능성을 극대화하기 위해 물고기를 먹는 물고기는 일반적으로 현장에서 먹을 수 있습니다 먹이 물고기를 공급해야한다.

호수 송어에 PCB의 동족체의 순 영양 전송 효율의 실험실 평가 (<em&gt; Salvelinus namaycush</em&gt;) 먹이에서

A technique for laboratory estimation of net trophic transfer efficiency (&#947;) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from ...

laboratory-estimation-net-trophic-transfer-efficiencies-pcb-congeners

Research

JoVE Journal

Environment

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey

10.9K 조회수.  U. S. Geological Survey.  먹이에서 물고기를 먹는 물고기 폴리 염화 비 페닐 (PCB) 이성체의 순 영양 전달 효율의 실험실 추정하는 기술이 제시된다. 필드로 실험 결과의 적용 가능성을 극대화하기 위해 물고기를 먹는 물고기는 일반적으로 현장에서 먹을 수 있습니다 먹이 물고기를 공급해야한다. 

비디오: Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

호수 퇴적물에서 실험실 결정 인 플럭스 내부 인 로딩의 측정으로

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

연구

환경과학

A Fish-feeding Laboratory Bioassay to Assess the Antipredatory Activity of Secondary Metabolites from the Tissues of Marine Organisms

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with the goal of examining the ecological functions of secondary metabolites from the tissues of marine organisms. The result has been a progression of protocols that have increasingly refined the ecological relevance of the experimental approach. Here we present the most up-to-date version of a fish-feeding laboratory bioassay that enables investigators to assess the antipredatory activity of secondary metabolites from the tissues of marine organisms. Organic metabolites of all polarities are exhaustively extracted from the tissue of the target organism and reconstituted at natural concentrations in a nutritionally appropriate food matrix. Experimental food pellets are presented to a generalist predator in laboratory feeding assays to assess the antipredatory activity of the extract. The procedure described herein uses the bluehead, Thalassoma bifasciatum, to test the palatability of Caribbean marine invertebrates; however, the design may be readily adapted to other systems. Results obtained using this laboratory assay are an important prelude to field experiments that rely on the feeding responses of a full complement of potential predators. Additionally, this bioassay can be used to direct the isolation of feeding-deterrent metabolites through bioassay-guided fractionation. This feeding bioassay has advanced our understanding of the factors that control the distribution and abundance of marine invertebrates on Caribbean coral reefs and may inform investigations in diverse fields of inquiry, including pharmacology, biotechnology, and evolutionary ecology.

This bioassay employs a model predatory fish to assess the presence of feeding-deterrent metabolites from organic extracts of the tissues of marine organisms at natural concentrations using a nutritionally comparable food matrix.

물고기 먹이 실험 생물 검정은 해양 생물의 조직에서 이차 대사 산물의 Antipredatory 활동을 평가하기 위해

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with ...

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. 
In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

This manuscript describes an automated gel size selection approach for purifying DNA fragments for next-generation sequencing. The Ranger Technology provides complete automation of the entire process of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments allowing for high-throughput and high quality next-generation sequencing libraries.

자동 젤 사이즈 선택은 환경 물 샘플에서 준비 차세대 시퀀싱 라이브러리의 질을 향상시키기 위해

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA ...

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic&#160;however; this method could have a broader use assessing CuO-NP treatment in more neutral waters.

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

Production bleed water (PBW) was treated with cupric oxide nanoparticles (CuO-NPs) and cellular toxicity was assessed in cultured human cells. The goal of this protocol was to integrate the native environmental sample into a cell culture format assessing the changes in toxicity due to CuO-NP treatment.

우라늄에서 구리 산화물 나노 입자에 의한 미량 원소의 제거<em&gt; 현장에서</em&gt; 복구 블리드 물과 세포 생존에 미치는 영향

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted ...

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

선캄브리아 해양 용승 시스템 광합성 박테리아의 성장을 탐구하는이 풍부한 철 (II)의 실험실 시뮬레이션

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and screening for the selection of a fast-acting, highly virulent entomopathogenic fungus are important steps. Entomopathogenic fungi, such as Metarhizium, Beauveria, and Nomurea, which act by contact, are better suited than Bacillus thuringiensis or nucleopolyhedrosis virus (NPV), which must be ingested by the insect pest. In the present work, we isolated 68 Metarhizium strains from infected insects using a soil dilution and bait method. The isolates were identified by the amplification and sequencing of the ITS1-5.8S-ITS2 and 26S rDNA region. The most virulent strain of Metarhizium anisopliae was selected based on the median lethal concentration (LC50) and time (LT50) obtained in insect bioassays against III-instar larvae of Helicoverpa armigera. The mass production of spores by the selected strain was carried out with solid-state fermentation (SSF) using rice as a substrate for 14 days. Spores were extracted from the sporulated biomass using 0.1% tween-80, and different formulations of the spores were prepared. Field trials of the formulations for the control of an H. armigera infestation in pigeon peas were carried out by randomized block design. The infestation control levels obtained with oil and aqueous formulations (78.0% and 70.9%, respectively) were better than the 63.4% obtained with chemical pesticide.

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

Here, we report the different stages involved in the knowledge-based development of an effective mycoinsecticide, including the isolation, identification, screening, and selection of the "best-fit" entomopathogenic fungus, Metarhizium anisopliae, for the control of insect pests in agriculture.

개발<em&gt; 메타 리지 움 anisopliae</em&gt; Mycoinsecticide로서의 : 분리에서 현장 성능까지

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

산화 질소 가스와 해충에 대 한 훈 증 실험실의 절차

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell counts. Plant materials used include roots, sprouts, leaves, and cut fruits. The methods described are inexpensive, easy, and suitable for small sample sizes. Binding is measured in the laboratory and a variety of incubation media and conditions can be used. The effect of inhibitors can be determined. Situations that promote and inhibit binding can also be assessed. In some cases it is possible to distinguish whether various conditions alter binding primarily due to their effects on the plant or on the bacteria.

An easy method for measuring and characterizing bacterial adhesion to plants, particularly roots and sprouts, is described in this article.

공장 실험실에서 측정 하는 표면에 박테리아의 부착

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Ecosystem Fabrication (EcoFAB) Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microbe interactions. Here, a detailed description for ecosystem fabrication is presented, using widely available 3D printing technologies, to create controlled laboratory habitats (EcoFABs) for mechanistic studies of plant-microbe interactions within specific environmental conditions. Two sizes of EcoFABs are described that are suited for the investigation of microbial interactions with various plant species, including Arabidopsis thaliana, Brachypodium distachyon, and Panicum virgatum. These flow-through devices allow for controlled manipulation and sampling of root microbiomes, root chemistry as well as imaging of root morphology and microbial localization. This protocol includes the details for maintaining sterile conditions inside EcoFABs and mounting independent LED light systems onto EcoFABs. Detailed methods for addition of different forms of media, including soils, sand, and liquid growth media coupled to the characterization of these systems using imaging and metabolomics are described. Together, these systems enable dynamic and detailed investigation of plant and plant-microbial consortia including the manipulation of microbiome composition (including mutants), the monitoring of plant growth, root morphology, exudate composition, and microbial localization under controlled environmental conditions. We anticipate that these detailed protocols will serve as an important starting point for other researchers, ideally helping create standardized experimental systems for investigating plant-microbe interactions.

Ecosystem Fabrication EcoFAB Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

This article describes detailed protocols for ecosystem fabrication of devices (EcoFABs) that enable the studies of plants and plant-microbe interactions in highly controlled laboratory conditions.

식물-미생물 상호작용 연구 위한 실험실 생태계의 건설에 대 한 생태계 제조 (EcoFAB) 프로토콜

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A ...

Laboratory and Field Protocol for Estimating Sheet Erosion Rates from Dendrogeomorphology

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to severe environmental impacts. The understanding of sheet erosion is, consequently, a worldwide issue with implications for both environment and economies. However, the knowledge on how erosion evolves in space and time is still limited, as well as its effects on the environment. Below, we explain a new dendrogeomorphological protocol for deriving eroded soil thickness (Ex) by acquiring accurate microtopographic data using both terrestrial laser scanning (TLS) and microtopographic profile gauges. Additionally, standard dendrogeomorphic procedures, dependent on anatomical variations in root rings, are utilized to establish the timing of exposure. Both TLS and microtopographic profile gauges are used to obtain ground surface pro&#64257;les, from which Ex is estimated after the threshold distance (TD) is determined, i.e., the distance between the root and the sediment knickpoint, which allows de&#64257;ning the lowering of the ground surface caused by sheet erosion. For each profile, we measured the height between the topside of the root and a virtual plane tangential to the ground surface. In this way, we intended to avoid small-scale impacts of soil deformation, which may be due to pressures exerted by the root system, or by the arrangement of exposed roots. This may provoke small amounts of soil sedimentation or erosion depending on how they physically affect the surface runoff. We demonstrate that an adequate microtopographic characterization of exposed roots and their associated ground surface is very valuable to obtain accurate erosion rates. This finding could be utilized to develop the best management practices designed to eventually halt or perhaps, at least, lessen soil erosion, so that more sustainable management policies can be put into practice.

Characterizing erosion from dendrogeomorphology has usually focused on accurately finding the starting time of root exposure, by examining macroscopic or cell level changes caused by exposure. Here, we offer a detailed description of different novel techniques to obtain more precise erosion rates from highly accurate microtopographic data.

실험실 및 필드 Dendrogeomorphology에서 시트 침식 속도 추정을 위한 프로토콜

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to ...