Decomposition and release of elements from zooplankton debris
Decomposition and release of elements from zooplankton debris
复制标题
浮游动物残骸中元素的分解和释放
DOI：
10.3354/meps088117
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发表时间：
1992
影响因子：
2.5
通讯作者：
N. Fisher
中科院分区：
文献类型：
--
作者：
N. Fisher
在研究分解浮游动物残骸中微量元素保留的实验中，使用放射性示踪剂测量了放射性标记的桡足动物粪便颗粒和尸体中C的降解率和金属释放率长达1个月。在18℃和2℃下孵育的粪丸在30天后分别保留了35 - 40%和80%的I4C。在18℃和2℃条件下，18 d后胴体的碳含量分别仅为13 ~ 18%和28 ~ 38%。即使在没有微生物活动的情况下，从粪便颗粒和尸体中以D0I4C的形式浸出的14C约占14C损失的一半。粪球中颗粒反应性超铀元素2 - 41 ~ n - 1的释放不受微生物活性的影响，而粪球和粪球中75Se和65 ~ n的释放随微生物活性的增加而增加，并与I4C损失密切相关。随着时间的推移，所有元素的释放率呈指数下降，在前6 d内下降最明显，粪丸中24 1 ~ m的保留半衰期（t,,,，’~）为248 d。相比之下，锌在粪丸中的t， 12,12的范围为2.1 ~ 13.5 d，两者都有。在尸体中只有大约1个小时。这一结果有助于解释海洋学观察结果，即C. Se和Zn在地表水中被循环利用，而被清除的元素如Am在粪便颗粒中富集，并且在地表水中停留时间短。
In experiments examining the retention of trace elements in decomposing zooplankton debris, the rates of C degradation and metal release from radiolabeled copepod fecal pellets and carcasses were measured for up to 1 mo using radlotracers. Fecal pellets incubated at 18 and 2 "C retained 35 to 40 % and 80 % of their I4C, respectively, after 30 d . Carcasses retained only 13 to 18 % and 28 to 38 % of their 14C after 18 d at 18 and 2 "C, respectively. Leaching of 14C from fecal pellets and carcasses as D0I4C accounted for about half of the 14C loss, even in the absence of microbial activity. Proportionately more of the 14C from carcasses was mlcrobially oxidized to I4CO2 than "C from fecal pellets Release of the particle-reactlve transuranic element 2 4 1 ~ n 1 from fecal pellets was unaffected by microbial activity while release of 75Se and 6 5 ~ n from both fecal pellets and carcasses increased with microbial activity and closely followed I4C loss. Release rates of all elements decreased exponentially over time, wlth the most pronounced decreases occurnng wlthin the first 6 d Retention half-times (t,,,, '~) of 2 4 1 ~ m were 248 d in fecal pellets. By contrast, the t,,12's for "Zn ranged from 2.1 to 13.5 d in fecal pellets and both and had t,,,?'s of only about 1 d in carcasses. The results help explain oceanographic observations that C. Se and Zn are recycled in surface waters while scavenged elements like Am are enriched in fecal pellets and have short residence times in surface waters.