Abstract Vertical mixing and stratification are among the most important physical processes controlling nutrient dynamics, the dominant category of primary producers and consequently the dominant types of food web, and are therefore important for the assessment of the marine ecosystem's response to global climate change. This study showed consistent short-term cyclic successions of the plankton food web types, governed by the dynamics of water column stability changes, occurring in generally oligotrophic, phosphate deficient surface waters of the open middle Adriatic Sea. The biogeochemical nitrogen cycle appeared as a key driving force responsible for the food web structure changes. The ‘herbivorous food web’ dominated during the nitrate-rich mixed water column period (winter) and gradually changed to ‘multivorous food web’ where large phytoplankton still constitute a significant fraction of phytoplankton. This intermediate type of food web lasted for a short time and quickly changed to the typical ‘microbial food web’, which then dominated during the stratified water column period (summer) and was characterised by a large proportion of picoplankton size-fraction organisms in total plankton biomass and production. Furthermore, at the very end of summer, the high bacterial carbon flux through the ‘microbial loop’ was established. The succession of food web types affects the mechanisms of bacterial control in a way that ‘bottom up’ control dominated during the mixed water column period and ‘top-down’ control prevailed during the stratified period. Since the ongoing global warming is expected to change water column stability dynamics and thereby significantly affect the supply of nutrients in surface waters, this study helps to understand the possible direction of changes in the plankton food webs of the Adriatic Sea, and consequent changes in marine nitrogen and carbon biogeochemical cycles.

中文翻译：

---

水柱稳定性动力学对亚得里亚海近海浮游生物食物网类型演替的影响

摘要 垂直混合和分层是控制养分动态的最重要物理过程之一，是初级生产者的主要类别，因此也是食物网的主要类型，因此对于评估海洋生态系统对全球气候变化的响应很重要。这项研究表明，浮游生物食物网类型的短期循环演替是一致的，受水柱稳定性变化的动力学控制，发生在开放的亚得里亚海中部一般贫营养、磷酸盐缺乏的地表水中。生物地球化学氮循环似乎是导致食物网结构变化的关键驱动力。“草食性食物网”在富含硝酸盐的混合水体时期（冬季）占主导地位，并逐渐转变为“多食性食物网”，其中大型浮游植物仍占浮游植物的很大一部分。这种中间类型的食物网持续时间很短，并迅速转变为典型的“微生物食物网”，然后在分层水柱时期（夏季）占主导地位，其特点是总体积较大的微型浮游生物大小分数生物浮游生物的生物量和产量。此外，在夏末，通过“微生物回路”建立了高细菌碳通量。食物网类型的演替以混合水体时期“自下而上”控制占优势，分层时期“自上而下”控制占优势的方式影响细菌控制机制。由于持续的全球变暖预计会改变水体稳定性动力学，从而显着影响地表水中营养物质的供应，这项研究有助于了解亚得里亚海浮游生物食物网变化的可能方向，以及随之而来的海洋变化。氮和碳生物地球化学循环。