Data from: Patterns in vertical distribution and their potential effects on transport of larval benthic invertebrates in a shallow embayment

Measurements of larval vertical distributions at high temporal and spatial resolutions as well as larval behavioural responses to environmental characteristics are needed to parameterize bio-physical models of larval dispersal or transport. We studied larval vertical distribution for 7 taxonomic groups (gastropods, bivalves, polychaetes, bryozoans, asteroids, carideans and brachyurans), with different morphology, swimming abilities and life-history strategies, and examined whether these vary with physical or biological factors and periodic cycles (diel period and tidal state) in the field. Using a pump, we collected plankton samples at 6 depths (3, 6, 9, 12, 18 and 24 m), over a 36 and a 26 h period. Temperature, salinity, fluorescence and current velocity were measured concurrently. Larval vertical distribution varied among taxonomic groups, but 4 patterns could be distinguished: (1) larvae exclusively in the mixed layer (asteroids), (2) larvae predominantly below the thermocline, halocline and pycnocline (gastropods, bivalves, polychaetes), (3) larvae associated predominantly with the fluorescence maximum (bryozoans and carideans) and (4) larval distribution varying dielly (gastropods, polychaetes, carideans and brachyurans). Based on flow velocities and depending on distribution, asteroid larvae were likely to be transported farther than those of bryozoans and carideans, while direction and magnitude of transport varied for the other larvae. For most taxonomic groups, behaviour observed in the field agreed with measured laboratory responses to relevant cues. For asteroids and bivalves, simple behavioural parameters can be generated that can be utilized to improve the accuracy of biophysical models.

为实现幼虫扩散或输运相关生物物理模型（bio-physical models）的参数化，亟需获取高时空分辨率的幼虫垂直分布测量数据，以及幼虫对环境特征的行为响应。本研究针对7个分类类群的幼虫垂直分布展开研究，涵盖腹足类（gastropods）、双壳类（bivalves）、多毛类（polychaetes）、苔藓虫类（bryozoans）、海星类（asteroids）、真虾下目（carideans）与短尾下目（brachyurans），这些类群具有各异的形态特征、游泳能力与生活史策略；同时考察了幼虫垂直分布是否随野外的物理/生物因子以及周期性循环（昼夜周期与潮汐状态）发生变化。研究团队采用泵采集浮游生物样本，在36小时与26小时的观测周期内，于3、6、9、12、18及24米共6个水层开展采样，并同步测量水温、盐度、荧光值与水流速度。幼虫垂直分布在不同分类类群间存在显著差异，但可归纳为4种典型模式：（1）仅分布于混合层的幼虫（海星类）；（2）主要栖息于温跃层、盐跃层与密度跃层下方的幼虫（腹足类、双壳类、多毛类）；（3）主要与荧光最大值层相关联的幼虫（苔藓虫类与真虾下目）；（4）分布随昼夜周期发生显著变化的幼虫（腹足类、多毛类、真虾下目与短尾下目）。基于水流速度数据与幼虫分布模式，海星类幼虫的输运距离大概率大于苔藓虫类与真虾下目，而其余类群幼虫的输运方向与强度则存在明显差异。对于多数分类类群，野外观测到的行为与实验室中测得的相关环境线索响应结果具有一致性。针对海星类与双壳类，可构建简易行为参数，用于提升生物物理模型的预测精度。