Numerical simulations of onshore transport of larvae and detritus to a steep pocket beach

Numerical simulations of onshore transport of larvae and detritus to a steep pocket beach

Fujimura, Atsushi G. (University of Guam; Rosenstiel School of Marine and Atmospheric Science)
Reniers, A.J.H.M. (TU Delft Environmental Fluid Mechanics; University of Miami)
Paris, Claire B. (University of Miami)
Shanks, Alan L. (University of Oregon)
MacMahan, Jamie H. (Naval Post Graduate School of Engineering and Applied Sciences)
Morgan, Steven G. (Davis)

2017-11-06

Larvae of intertidal invertebrates need to cross the surf zone to settle in their adult habitat. Onshore transport of invertebrate larvae and detritus at a steep beach was simulated with a biophysical larval tracking model. Hydrodynamic model calculations were performed for 24 h after a 24 h spin-up stage with bathymetry and averaged wave data obtained during the summer of 2011 at Carmel River State Beach, California, and with and without onshore wind. The physical model output was then transferred to a Lagrangian larval tracking model using several types of particles representing larvae. A southward alongshore current controlled particle distribution in the middle and north of the domain. At the southern shore, negatively buoyant particles were trapped by eddies generated between the alongshore current and shore, while positively buoyant particles were carried onshore by wind-driven surface currents. The concentration of modeled detritus in the surf zone was positively correlated with that of negatively buoyant larvae. Additionally, the concentrations of detritus and competent larvae within the surf zone were negatively correlated with wave height, consistent with the observations of the accompanying field study. Some eddies contributed to forming high particle concentration patches by trapping them in the surf zone. More small eddies were generated closer to the shore with smaller waves, leading to high larval and detrital concentration in the surf zone. As waves increased in size, fewer and larger eddies formed, predominantly outside the surf zone, and consequently fewer larvae and detritus particles entered or stayed in the surf zone.

Biophysical model
Competent larvae
Detritus
Eddies
Larval transport
Steep beach
Surf zone

http://resolver.tudelft.nl/uuid:ade6a8ee-424e-4d81-86e4-1ebc261e02dd

https://doi.org/10.3354/meps12331

0171-8630

Marine Ecology - Progress Series, 582, 33-43

Institutional Repository

journal article

© 2017 Atsushi G. Fujimura, A.J.H.M. Reniers, Claire B. Paris, Alan L. Shanks, Jamie H. MacMahan, Steven G. Morgan