Progressive decoupling between phytoplankton growth and microzooplankton grazing during an iron-induced phytoplankton bloom in the Southern Ocean (EIFEX)
Progressive decoupling between phytoplankton growth and microzooplankton grazing during an iron-induced phytoplankton bloom in the Southern Ocean (EIFEX)
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南大洋铁诱导浮游植物大量繁殖期间浮游植物生长与微型浮游动物放牧之间的渐进脱钩（EIFEX）
DOI：
10.3354/meps10937
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发表时间：
2014
影响因子：
2.5
通讯作者：
V. Smetácek
中科院分区：
文献类型：
--
作者：
M. Latasa;Joachim Henjes;R. Scharek;P. Assmy;R. Röttgers;V. Smetácek
稀释实验进行量化的生长和死亡率的浮游植物群体（定义的色素标记）5周的铁诱导的浮游植物水华在欧洲铁施肥实验（EIFEX）在南大洋进行。率可以可靠地测量的2个主要群体，硅藻和prymnesiophytes。浮游植物的平均内禀生长率约为0.23 d-1，没有明显的时间趋势。然而，死亡率随着时间的推移而下降（从~0.3到~0.06 d1），导致浮游植物生长和微型浮游动物放牧之间的脱钩增加。放牧的减少与小型原浮游动物（<60 µm）浓度的减少有关。因此，在稀释实验中，净生长从大约0 d1增加到实验最后几天的0.13 d1，在最初的铁施肥后35 d。这种模式并没有反映出动态的净浮游植物积累的施肥补丁，增加，直到第24至27天，此后下降。实验和自然浮游植物净增长之间的差异是逃脱微型浮游动物放牧的生物量，而不是在表面混合层中积累，即进入更高营养级的生物量加上从混合层输出的生物量。它在整个EIFEX增加，并建议从主要回收系统转向更多的出口系统。
Dilution experiments were performed to quantify growth and mortality rates of phytoplankton groups (as defined by pigment markers) for 5 wk in an iron-induced phytoplankton bloom during the European Iron Fertilization Experiment (EIFEX) conducted in the Southern Ocean. Rates could be reliably measured for the 2 main groups, diatoms and prymnesiophytes. Mean phytoplankton intrinsic growth rates were around 0.23 d �1 , without a significant temporal trend. Mortality rates, however, decreased with time (from ~0.3 to ~0.06 d �1 ), leading to an increase in decoupling between phytoplankton growth and microzooplankton grazing. The decrease in grazing was correlated with the decrease in concentrations of small microprotozoo- plankton (<60 µm). As a consequence, net growth in the dilution experiments increased from around 0 d �1 up to 0.13 d �1 in the last days of the experiment, 35 d after the initial iron fertilization. This pattern did not reflect the dynamics of net phytoplankton accumulation in the fertilized patch, which increased until Days 24 to 27 and decreased thereafter. The difference between experimental and natural phytoplankton net growth is the biomass that escapes microzooplankton grazing and does not accumulate in the surface mixed layer, i.e. the biomass that went to higher trophic levels plus that exported out of the mixed layer. It increased throughout EIFEX and sug- gests a shift from a predominantly recycling system towards a more exporting one.
DOI：
10.1073/pnas.1309345110
发表时间：
2013-12-17
影响因子：
11.1
作者：
Assmy, Philipp;Smetacek, Victor;Wolf-Gladrow, Dieter
通讯作者：
Wolf-Gladrow, Dieter