Stratification and Tidal Current Effects on Larval Transport in the Eastern English Channel: Observations and 3D Modeling |
| |
Authors: | Alexei Sentchev Konstantin Korotenko |
| |
Institution: | 1. UMR 8013 Ecosystèmes Littoraux et C^otiers - ELICO, Université du Littoral, C?te d'Opale, 32 Av. Foch, 62930, Wimereux, France 2. P.P. Shirshov Institute of Oceanology, 36 Nakhimovsky, 117851, Moscow, Russia
|
| |
Abstract: | We study how the combination of tides and freshwater buoyancy affects the marine organisms accumulation and horizontal transport
in the ROFI system of the eastern English Channel. The Princeton Ocean Model coupled with a particle-tracking module is used
to study the migration of fish eggs and larvae under different forcing conditions. Results of modeling are validated against
observed concentrations of Flounder (Pleuronectes flesus) larvae. Numerical Lagrangian tracking experiments are performed with passive and active particles, representing sea-water
organisms. Passive particles are neutrally buoyant whereas active particles are able to exercise light dependent vertical
migrations equating to the swimming behavior of larvae. The experiments reveal that the strongest accumulation of particles
occurs along the French coast on the margin of the ROFI. This happens because the interaction between the turbulence, the
freshwater buoyancy input, and tidal dynamics, produces particle trapping and vertical spreading within the frontal convergence
zone. Tides and freshwater input induce net alongshore horizontal transport toward the North. Tidal currents modulate the
magnitude of horizontal transport whereas the fresh water input controls more the location of accumulation zones. Tracking
experiments with active particles indicate that the vertical migration leads to a significant departure from the passive particle
transport pattern. Differences lie in the shape of the particle transport pattern and the rate of the northward migration.
In particular, vertically migrating particles travel slower. To find possible Flounder migration pathways, particles are released
within the assumed spawning area of Flounder. The model predicts larvae drift routes and demonstrates that throughout the
entire particle-tracking period the horizontal structure of the particle distribution is consistent with the larvae concentrations
observed during the field experiments. |
| |
Keywords: | English Channel freshwater buoyancy larval transport particle tracking tides |
本文献已被 SpringerLink 等数据库收录! |
|