Black Band Disease Pathogenesis and Impacts in the Florida Keys

Joshua Voss, Daniel Rowan, and Sara EdgeRobertson Coral Reef Program, CIOERT

Regulation of Pathogenesis1) Invasion of infectious

bacteriaBacteria(agent)

Disease

Environment

3) Change in environment reduces coral defenses

A. via changes in coral physiology (zoox?)

B. via changes in resident bacteria abundance or physiology

2) Change in environment results in increased pathogen virulence

Coralholobiont

(host)EnvironmentEnvironment

CoralCoralholobiontholobiont

(host)(host)

Survey and Sampling LocationsRCRP FKNMS CDCURICIOERT

0123456789

10

01 02 03 04 05 06 07 08 09

Prolonged elevated temperature impacts coral bleaching and disease

• Maximum Degree Heating Weeks (DHW)

FL Keys

0%

2%

4%

6%

8%

10%

12%

2002 2003 2004 2005 2006 2007 2008 2009

BB

D P

reva

lenc

e RCRP and FKNMS Coral Health Cruise Data:BBD Prevalence among Susceptible Species

DHW

Colpophyllia natans

Siderastrea siderea

Montastraea spp

Years of Recurring Infection

Col

onie

s E

xper

ienc

ing

Tota

l Mor

talit

y (%

)Likelihood of total colony mortality due to BBD

0%

2%

4%

6%

8%

10%

12%

1 2 3 4 5 6

Effect of BBD on Coral Tissue Surface Area

Years from initial BBD observation

Colpophyllia natans

Siderastrea siderea

0100020003000400050006000700080009000

10000

1 2 3 4 5 6

Mea

n C

olon

y S.

A. (

cm2 )

Effect of nutrient enrichment on BBD migration in situ

0

5

10

15

20

25

30

0 5 10 15 20

nutrient dosed (n=10)

control (n=10)

days

band

mig

ratio

n (m

m)

Voss and Richardson 2006, Coral Reefs

1) progression rates of BBD2) composition of the bacterial communities of

the host coral mucus and BBD3) gene expression of coral and zooxanthellae4) immune activity of coral (Mydlarz)

Ex-situ experiment: temperature, light, and colony effects on BBD pathogenesis

Raceway A Raceway B Raceway C

12.5% (10m) 35% (2m)

LightInfectedControl

BBDAmb. (27-30 oC) Elev. (30-33 oC)

Temp

Ambient temp35% LightColony - C

0 mm 3 mm 6.8 mm

0 mm 9 mm 24.2 mm

BBD Progression

0 mm 3 mm 13.2 mm

Day 1 Day 4 Day 7

Ambient Temp35% LightColony - A

Elev Temp35% LightColony - A

0123456

1

BBD progression rates inlight and temperature treatments

12.5% lightAmbient temp

12.5% lightElev. temp

35% lightAmbient temp

35% light Elev. temp

Ave

rage

pro

gres

sion

(mm

/day

)

BBD Progression colony comparison

012345678

1

F = 9.94df = 4p < 0.01

A B C D EColonies

Ave

rage

pro

gres

sion

(mm

/day

)

Are Corals Tough Enough?

• Not just who…but why

• Are certain areas or coral populations more resistant to disease in the Florida Keys?

• Are particular coral or zooxanthellae genotypes more resistant to disease?

• Do resistant corals harbor different bacterial assemblages than susceptible corals?

• Do any of the above change when environmental conditions are altered?

Summary• Annual BBD recurrence common (20-55%) in FL

– increased coral tissue lost and an improved likelihood of total colony mortality

– excess nutrients exacerbate BBD infections

• Temperature experiment indicates upper threshold to BBD enhancement effects– severity vs. prevalence

• Coral disease susceptibility varies among colonies within and between species– Are these patterns predictable? – How might this impact restoration activities?

• Diagnostics and training to quantify coral health beyond measures of mortality

• Improved techniques to identify susceptible populations or regions

Acknowledgments

Dennis Hanisak – HBOI@FAUSara Edge – HBOI@FAUJohn Reed – HBOI@FAUDan Rowan - FAU

Erich Bartels - MoteCory Walter - MoteAshley Voss - USDA/ HBOI

Brian Keller - NOAALauri Maclaughlin - FKNMSScott Donahue – FKNMSErich Mueller - PIMSCDC Teams

Dee Mills - FIULaura Mydlarz – UTAGraham Forrester - URI

The Banbury Fund River Branch Foundation