Phytoplankton size diversity and ecosystem function relationships across oceanic regions

Trait diversity, a key component of biodiversity, mediates many essential ecosystem functions and services. However, the mechanisms behind such relationships at large spatial scales are not fully understood. Here we adopt the functional biogeography approach to investigate how the size composition of phytoplankton communities relates to primary production and export production along a broad latitudinal gradient. Using in situ phytoplankton size distribution data and a trait-based model, we find an increase in the average phytoplankton size, size diversity, primary production, and export when moving from low to high latitudes. Our analysis indicates that the interplay between spatiotemporal heterogeneities in environmental conditions and a trade-off between the high affinity for nutrients of smaller cells and the ability to avoid predation by larger cells are the main mechanisms driving the observed patterns. Our results also suggest that variations in size diversity alone do not directl...性状多样性（Trait diversity）作为生物多样性的核心组成部分，调控着诸多关键生态系统功能与服务。然而，在大空间尺度下，这种关联背后的机制尚未完全阐明。本研究采用功能生物地理学（functional biogeography）方法，探究沿宽广纬度梯度的浮游植物群落粒径组成与初级生产、碳输出生产之间的关联。本研究利用原位（in situ）浮游植物粒径分布数据与基于性状的模型（trait-based model），发现在从低纬度向高纬度过渡的过程中，浮游植物平均粒径、粒径多样性（size diversity）、初级生产与碳输出生产均呈上升趋势。分析结果表明，环境条件的时空异质性，与小型细胞对养分的高亲和性和大型细胞规避捕食的能力之间的权衡效应，共同构成了驱动上述观测模式的核心机制。本研究结果同时表明，仅靠粒径多样性的变化并不能直接...