Behavior Matters: A Bio-Physical Model for the Dispersal of Deep-Sea Larvae

Doreen McVeigh1; D.B. Eggleston1; R. He1; A. Todd1; C. Young2 1Marine, Earth, and Atmospheric Sciences, North Carolina State University; 2Oregon Institute of Marine Biology, University of Oregon

Background: Methods: Results: What are Methane Seeps? Model Domain and Particle Simulations How Does Larval Behavior Affect Dispersal?

Methane seeps are areas of the seafloor where methane, sulfide, and US East Model hydrocarbons seep into the surrounding . Fascinating creatures 700 no behavior can be found inhabiting seeps, such as tubeworms, mussels, clams, and behavior 600 crabs. Similar to hydrothermal vents, methane seeps host biological Model Specs: 500 communities that use chemical, not photosynthetic, processes to derive their • 7—10 km horizontal resolution 400 energy. • 36 vertical grid layers 300 200 Monthly Climatology Forcing: Distance Traveled (km) 100 0 AC BP FE BR CF • Seasonal Cycle Site • No inter-annual variability Effects of site and larval behavior (with vs without) on mean (+SE) distance travelled by • Run 10 consecutive cycles, and B. naticoidea over a 90-Day PLD. AC = Alaminos Canyon, BP = Pool, FE = Florida average last 5 for mean state Escarpment, BR = Blake Ridge, and CF = Cape Fear Diapir. Figure 3. US East model domain and the five methane seep particle release sites.

900 no behavior Results: 800 behavior Figure 1. Methane seep invertebrates (L-R): octopus, shrimp, snails, and tubeworms. 700 600 How Does Larval Behavior Affect Dispersal? 500 400 300 Why is Larval Behavior Important? Larval Dispersal Maps: 200

Distance Traveled (km) 100 The free swimming larval phase is the only opportunity for species to 30,000 particles were released per site. 0 AC BP FE BR CF find new, suitable habitat. Site Currents only (figure on the right) trajectories Effects of site and larval behavior (with vs without) on mean (+SE) distance travelled by illustrate the dispersal paths without behavior. A. muricola over a 186-Day PLD. AC = Alaminos Canyon, BP = Brine Pool, FE = Florida Escarpment, BR = Blake Ridge, and CF = Cape Fear Diapir. The following figures show species-specific trajectories with behavior.

300 no behavior Larvae no behavior behavior 250 600 behavior

500 200 400 150 Adults 300 100

A. Mussel B. Snail C. Shrimp D. Tubeworm 200 50 Distance Traveled (km)

Distance Traveled (km) 100 Figure 2. 0 0 AC BP FE A.Bathymodiolus childressi; 13 month Pelagic Larval Duration, Demersal drift AC BP FE BR CF Site B.Bathynerita naticoidea; 3 month Pelagic Larval Duration, Thermocline drift Site Effects of site and larval behavior (with vs without) on mean (+SE) distance travelled by C.Alvinocaris muricola; 6 month Pelagic Larval Duration, Surface drift L. luymesi over a 21-Day PLD. AC = Alaminos Canyon, BP = Brine Pool, and FE = Florida D.Lamellibrachia luymesi; 21 day Pelagic Larval Duration, Thermocline drift Effects of site and larval behavior (with vs without) on mean (+SE) distance travelled by Escarpment. B. childressi over a 395-Day PLD. AC = Alaminos Canyon, BP = Brine Pool, FE = Florida Escarpment, BR = Blake Ridge, and CF = Cape Fear Diapir.

Study Objectives Acknowledgements Summary

The goal of this study is to assess the effect of larval behavior on dispersal Dissertation Committee, Department of Marine, Earth, and Atmospheric Science, Marine Ecology and Computer models serve as useful tools to address knowledge gaps and Conservation Lab, Ocean Observing and Modeling Group, Oregon Institute of Marine Biology, Duke distance and pathways using species-specific biological parameters in a University Marine Lab, Crew of R/V Atlantis, Endeavor, Cape Hatteras, Pelican, and Walton Smith. understand potential levels of population connectivity across methane seeps in coupled biophysical model. the Western Atlantic. These four species, each with their own behaviors and PLDs, highlight the importance of incorporating biological parameters for more accurate results.