Dynamics of phytoplankton and nutrient uptake following dust additions in the northwest Pacific
Dynamics of phytoplankton and nutrient uptake following dust additions in the northwest Pacific
复制标题
西北太平洋灰尘添加后浮游植物和养分吸收的动态
DOI：
10.1016/j.scitotenv.2020.139999
复制
发表时间：
2020
影响因子：
9.8
通讯作者：
Huiwang Gao
中科院分区：
文献类型：
--
作者：
Chao Zhang;Jingyi He;Xiaohong Yao;Yingchun Mu;Xinyu Guo;Xiaokun Ding;Yang Yu;Jinhui Shi;Huiwang Gao
灰尘沉积可以提供影响海洋浮游植物的营养物质，但海洋表层营养状态的变化增加了解释这一过程的复杂性。本研究在西北太平洋黑潮延伸区（KE）和黑潮-大屋潮过渡区（TR）分别进行了4个不同营养盐和沙尘的培养实验。营养盐添加实验表明，在营养盐池中，浮游植物受氮（N）限制，在营养盐池中，浮游植物受铁（Fe）限制或受铁、磷（P）共同限制。粉尘添加提供了相当数量的N和Fe，但可以忽略不计的P量，以刺激浮游植物的生长，叶绿素（Chla）浓度所示。在KE培养过程中，灰尘的加入促进了浮游植物尺寸结构从主要是微微尺寸（0.2-2 μm）的Chlato向更大细胞的转变，每个尺寸类别（即皮科，纳米：2-20 μm，微米：>20 μm）的贡献相当。的基础上的大型转变的大小结构对纳米或微型浮游植物在未经修正的控制处理在TR，粉尘添加进一步促进了转变对微型浮游植物成为主要贡献者的总叶绿素a。对两个区域实验数据的综合分析表明，随着营养盐（包括N、P和硅）吸收量的增加，浮游植物生长刺激的程度和向大型细胞的转移逐渐增强。浮游植物的营养盐吸收率收敛到雷德菲尔德比相比，在更广泛的范围内的营养盐比的灰尘修正的海水。这项研究表明，浮游植物的生长，大小结构的转变，营养吸收的动态增加粉尘后，在KE和TR，虽然营养状态和限制营养这两个地区之间的变化。
Dust deposition can supply nutrients that affect marine phytoplankton, but changing trophic statuses of the surface ocean increase the complexity of interpreting the process. In this study, four onboard incubation experiments amended with various nutrients and dust were performed in theKuroshioExtension (KE) andKuroshio–Oyashiotransition (TR) of the northwest Pacific (NWP), which are characterised by lower and higher trophic statuses, respectively. According to the nutrient-addition experiments, phytoplankton were limited by nitrogen (N) in the KE, and limited by iron (Fe) or co-limited by Fe and phosphorus (P) in the TR. Dust additions supplied a considerable amount of N and Fe but negligible amount of P to stimulate phytoplankton growth, as indicated by chlorophylla(Chla) concentration. In the KE incubations, dust additions enhanced the shift of phytoplankton size structure towards larger cells from dominantly pico-sized (0.2–2 μm) Chlato comparable contributions from each size class (i.e. pico-, nano-: 2–20 μm, micro-: >20 μm). On the basis of the large shift of size structure towards nano- or micro-phytoplankton in the unamended control treatments in the TR, dust additions furtherly promoted the shift towards micro-phytoplankton becoming the dominant contributor to the total Chla. The collective analysis of the data from experiments in both regions revealed that, the extent of phytoplankton growth stimulation and the shift towards larger cells were enhanced gradually with increasing amounts of nutrient uptake (including N, P, and silicon). The nutrient uptake ratios of phytoplankton converged towards the Redfield ratio in comparison to the wider range of nutrient ratios in the dust-amended seawater. This study suggested consistencies in the dynamic of phytoplankton growth, shift of size structure, and nutrient uptake following dust additions in the KE and TR, although the trophic status and limiting nutrient varied between these two regions.