Physical and biological factors affect the vertical distribution of larvae of benthic gastropods in a shallow embayment

Marine Ecology Progress Series

Michelle J. Lloyd¹  Brad deYoung¹  Anna Metaxas¹ 

关键词: Vertical migration;    Temperature;    Fluorescence;    Lunar phase;    Diel period;    Tidal state;    Water column structure;    Stratification;   

DOI  :  10.3354/meps09872

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Marine gastropods form a diverse taxonomic group, yet little is known about the factors that affect their larval distribution and abundance. We investigated the larval vertical distribution and abundance of 9 meroplanktonic gastropod taxa (Margarites spp., Crepidula spp., Astyris lunata, Diaphana minuta, Littorinimorpha, Arrhoges occidentalis, Ilyanassa spp., Bittiolum alternatum and Nudibranchia), with similar morphology and swimming abilities, but different adult habitats and life-history strategies. We explored the role of physical (temperature, salinity, density, current velocities) and biological (fluorescence) factors, as well as periodic cycles (lunar phase, tidal state, diel period) in regulating larval vertical distribution. Using a pump, we collected plankton samples at 6 depths (3, 6, 9, 12, 18 and 24 m) at each tidal state, every 2 h over a 36 and a 26 h period, during a spring and neap tide, respectively, in St. George’s Bay, Nova Scotia. Concurrently, we measured temperature, salinity, density, fluorescence (as a proxy for chlorophyll, i.e. phytoplankton density), and current velocity. Larval abundance was most strongly related to temperature, except for Littorinimorpha and Crepidula spp., for which it was most strongly related to fluorescence. Margarites spp., A. lunata, Ilyanassa spp. and B. alternatum exhibited either diel or reverse-diel vertical migration during 1 or both lunar phases. For Crepidula spp., Littorinimorpha, A. occidentalis and Nudibranchia, larval vertical distribution differed between lunar phases. Only the larval vertical distribution of Margarites spp., D. minuta and Ilyanassa spp. varied with tidal state during 1 or both lunar phases. The key factors determining the vertical distribution of gastropod larvae were temperature, fluorescence, and light, although the importance of each factor varied among taxa. Differences in vertical distribution may enable these larvae to partition over a wide range of potential habitats for settlement.

【 授权许可】

Unknown