Functional Response of Larvae to Temperature

Changes

Tim Chaffey, Satoshi Mitarai, Brian Kinlan, Michael O’Donnell,

Mary O’Connor (UNC)

LARVAL TRAJECTORIES ON SST

• Larvae mostly move along SST contours, due to Geostrophic balance– Particle’s temperature

change should be mainly due to mixing and diffusion

• But, sometimes larvae cross temp contours– Geostrophic balance

does not always hold– Leads to significant jump

in temperature

TEMPERATURE CHANGE DURING PLD

Summer Winter(Temperature change that each settler undergoes during its PLD)

Temperature change during PLD (C) Temperature change during PLD (C)

1998-1999 Observed Temperature

Eight Year Annual Harmonic

Universal Relationship between PLD and Temperature

• From Brian’s talk last week --

ln(PLD) = B0 + 0.16*ln(T) - 0.28*(ln(T))2

• 0.16 and 0.28 are are derived by averaging all the data across species.

• B0 is calculated for each species using the PLD at 15oC.

ln(PLD) = B0 + .16*ln(T) - 0.28*(ln(T))2

Four Scenarios

• Constant - Constant PLD (20-40 days) derived from constant temperature (13oC)

• Start - Constant PLD derived from each particle’s starting temperature.

• Instant - Fluctuating PLD derived from particle’s present temperature.

• Avg. - Evolving PLD derived from a running mean of the temperature particle experiences.

Hypothetical PLD-Temperature Dependence

Extreme - Mean PLD defined by Mean PLD = -10*T+160

@ 10oC Mean PLD = 60 days (40-80 days)

@ 15oC Mean PLD = 10 days (13-6 days)

Histogram of Settler’s Initial Temperature

Histogram of All Particles Initial Temperature

Extreme

StartConstant

Settler’s Larval Duration

Constant Start Instant Avg.

Connectivity Matrix - 1

Constant Start Instant Avg.

Connectivity Matrix - 2

Constant Start

Instant Avg.

Dispersal Kernel - 2

Constant Start

Instant Avg.

Dispersal Kernel - 2

Extreme Case Refresh

• Compare the Constant case to an Extreme case.– Constant - Constant PLD range (20-40

day) derived from constant temperature (13oC)

– Extreme - Mean PLD defined by Mean PLD = -10*T+160

@ 10oC Mean PLD = 60 days (40-80 days) @ 15oC Mean PLD = 10 days (13-6 days)

Connectivity Matrix - 1 Revisited

Constant Extreme

Dispersal Kernel - 1 Revisited

Constant Extreme

Constant Extreme

Connectivity Matrix - 2 Revisited

Dispersal Kernel - 2 RevisitedConstant Extreme

Discussion

• Settling particles are being advected along same water parcel from start to settlement.

• If P

DispersalSurvival

Planktonic larval duration

TTLarval development(Metabolic rate)

EcologyEvolutionConservation

PLD = em*T b1+ b2*lnT