title: Prey size diversity hinders biomass trophic transfer and predator size diversity promotes it in planktonic communities.
abstract: Body size exerts multiple effects on plankton food-web interactions. However, the influence of size structure on trophic transfer remains poorly quantified in the field. Here, we examine how the size diversity of prey (nano-microplankton) and predators (mesozooplankton) influence trophic transfer efficiency (using biomass ratio as a proxy) in natural marine ecosystems. Our results support previous studies on single trophic levels: transfer efficiency decreases with increasing prey size diversity and is enhanced with greater predator size diversity. We further show that communities with low nano-microplankton size diversity and high mesozooplankton size diversity tend to occur in warmer environments with low nutrient concentrations, thus promoting trophic transfer to higher trophic levels in those conditions. Moreover, we reveal an interactive effect of predator and prey size diversities: the positive effect of predator size diversity becomes influential when prey size diversity is high. Mechanistically, the negative effect of prey size diversity on trophic transfer may be explained by unicellular size-based metabolic constraints as well as trade-offs between growth and predation avoidance with size, whereas increasing predator size diversity may enhance diet niche partitioning and thus promote trophic transfer. These findings provide insights into size-based theories of ecosystem functioning, with implications for ecosystem predictive models.
authors: Institute of Oceanography, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan Marine Ecosystem Dynamics Research Group, Research and Development Center for Global Change, Japan Agency for Marine-Science and Technology (JAMSTEC), 3173-25, Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan carmencomas@gmail.com.
authors: Carmen
authors: C
authors: García-Comas
authors: Ocean Networks Canada, University of Victoria, Victoria, British Columbia, Canada.
authors: Akash R
authors: AR
authors: Sastri
authors: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan 430072, China.
authors: Lin
authors: L
authors: Ye
authors: Institute of Oceanography, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan.
authors: Chun-Yi
authors: CY
authors: Chang
authors: Institute of Oceanography, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan.
authors: Fan-Sian
authors: FS
authors: Lin
authors: Institute of Oceanography, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan.
authors: Min-Sian
authors: MS
authors: Su
authors: Institute of Marine Environment and Ecology and Center of Excellence for the Oceans, National Taiwan Ocean University, 2, Pei-Ning Road, Keelung 20224, Taiwan.
authors: Gwo-Ching
authors: GC
authors: Gong
authors: Institute of Oceanography, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan Institute of Ecology and Evolutionary Biology, National Taiwan University, No. 1, Sector 4, Roosevelt Road, Taipei 10617, Taiwan chsieh@ntu.edu.tw.
authors: Chih-Hao
authors: CH
authors: Hsieh
mesh_terms: D018533:Biomass; D020387:Food Chain; D010140:Pacific Ocean; D010933:Plankton / Q000502:physiology*; D013624:Taiwan
keywords: biodiversity–ecosystem functioning; body size; functional diversity; predator–prey dynamics; size diversity; trophic transfer efficiency