Déjà Vu All Over Again: The Impact of Recent ... · % Killed 0 20 40 60 80 100 120 140 Spongia...
Transcript of Déjà Vu All Over Again: The Impact of Recent ... · % Killed 0 20 40 60 80 100 120 140 Spongia...
Mark ButlerOld Dominion University, Norfolk, Virginia
Don BehringerUniversity of Florida, Gainesville, Florida
Déjà Vu All Over Again: The Impact of Recent Cyanobacteria
Blooms on Hard-bottom Communities in Florida Bay and the Florida Keys
Nearly Two Decades Ago (1991-1992)A Cascade of Disturbances in Florida Bay
Changes inWater Quality
Seagrass Die-off
CyanobacteriaBloom
Sponge Die-off
Impacts onCrevice-dwelling
Fauna(e.g. Lobster)
• Documented changes in sponge community structure
• Documented changes in juvenile lobster population structure,shelter use, & recruitment
• Hypothesized ecological linkages: blooms → sponges → lobster
1991-1992 Sponge Die-off Studies by My Colleagues & I
Photo Credit: Rod Bertelsen
“ When one tugs at a single thing in nature,one finds it attached to the rest of the world.”
- John Muir
Monitoring of Hard-bottom
Sponge Research:• Population dynamics (growth, reproduction, recruitment)
• Tolerances for salinity, temperature& water quality correlations
• Filtration rates & particle selectivity• Sponge fishery effects
Modeling:• Salinity & bloom impacts on lobster recruitment and sponge/octocoral community structure
Our Subsequent Research on Hard-bottom
Déjà VuA Cascade of Disturbances in Florida Bay 2007
Changes in Water Quality
Seagrass Die-off
CyanobacteriaBloom
Sponge Die-off
Impacts onCrevice-dwelling
Fauna(e.g. Lobster)
Hard-bottom Monitoring: 2002 - 2007Sites• 132 sites in 2002; 32 -40 sites in 2003-2007
Methods• surveyed annually in June/July• 4 permanent 2 x 25m transects/site• 16 permanent 1m2 quadrats/site
Measurements• Abundance of 55 taxa (24 spp. sponge)• Size structure selected sponges & octocorals• Lobster population structure & disease
2002 - 20072002 Only
Pre-bloom & Post-bloom Surveys 2007 -2008
Survey locations
N
10 km
• 18 sites chosen from the central region of our hard-bottom monitoring program survey sites
• Hard-bottom surveys: July 2007 & Oct 2007• Lobster surveys: July 2007, Mar 2008, & July 2008
2007 Bloom Impacts on Sponges
Survey locations
N
10 km
Severe Impacts- 22 of 24 sponge species killed
Loggerhead sponges: ↓ 100%Vase sponges: ↓ 100%Commercial sponges: ↓ 100%Other sponges: ↓ 90%
2007 Bloom Impacts on Sponges
Survey locations
N
10 km
Moderate ImpactsSevere Impacts
Loggerhead sponges: ↓ 67%Vase sponges: ↓ 90%Commercial sponges: ↓ 95%Other sponges: ↓ 50%
2007 Bloom Impacts on Sponges
Survey locations
N
10 km
Moderate ImpactSevere Impact
Little or No Impact
% Killed0 20 40 60 80 100 120 140
Spongia barbaraSpongia cheris
Spongia gramineaIrcinia felix
Hippospongia lachneHytrios sp.
Anthosigmella variansAaptos sp.
Haliclona/GeodiaLissodendoryx sp.
Aplysinia sp.Halichondria melandocia
Ircinia campanaChondrilla nuclea
Tedania ignisTethya crypta
Adocia sp.Ircinia sp.
Speciospongia vespariaNiphates erecta
Cinachyra sp.
Mean+ 1sd
Vulnerability of Sponge Species(Percentage of each species killed on bloom-impacted sites)
MostTolerant
LeastTolerant
• Sponge filtration efficiency varies among seasons and species
• Sponge filtration efficiency declines precipitously at bloom cell densities(Peterson & Fourquerean)
Mechanism of Sponge Die-off?
% B
acte
ria R
emov
ed
0
20
40
60
80
100
GolfballLoggerhead
SheepswoolBranching
Yellow Vase Glove
SummerWinter
N = 5 - 20
• The more efficient sponge species are the least tolerant of blooms,especially in summer when blooms typically develop
% Killed0 20 40 60 80 100 120 140
Spongia barbaraSpongia cheris
Spongia gramineaIrcinia felix
Hippospongia lachneHytrios sp.
Anthosigmella variansAaptos sp.
Haliclona/GeodiaLissodendoryx sp.
Aplysinia sp.Halichondria melandocia
Ircinia campanaChondrilla nuclea
Tedania ignisTethya crypta
Adocia sp.Ircinia sp.
Speciospongia vespariaNiphates erecta
Cinachyra sp.
Mean+ 1sd
Least Tolerant
Most Tolerant
More EfficientLessEfficient
Mechanical Inhibition of Filtration?
Loss of Filtration Capacity in System• Sponges are largest & most abundant
(biomass) filter feeders in this ecosystem
Per hectare: 4410 large sponges (>20cm dia)289,000 small sponges
• Sponges efficient consumers bacteria-sized particles; often > 80% particle removal efficiency
Consequences of Sponge Die-off
Following the 1991 die-off:“... we calculated that prior to the sponge die-off the sponge community could filter thewater column every 3d. In contrast, it would now take 15d for the surviving sponge community to do the same.”
(Peterson et al 2006)
Loss of Sponge Infaunal Animal Communities
• Large sponges harbor within their internal canals a variety of macroinvertebrates
Consequences of Sponge Die-off
Photo credit: D. Rubensteinwww.biology-blog.com/images
Zuzalpheus spp.
• Some are obligate sponge-dwellers, including the only known eusocial marine animals (snapping shrimp)
Loss of Sponge Infaunal Animal Communities
• Change in hard-bottom community “sound-scape”
Consequences of Sponge Die-off
Unimpacted Sites
Sponge Die-off Sites
Loss of Shelter for Crevice-dwelling Animals (e.g., Juvenile Spiny Lobster)
Consequences of Sponge Die-off
• Shelter use & aggregation• Abundance• Nutritional condition• Disease
Juvenile lobsters sheltering under spongePhoto credit: Rod Bertelsen
Lobster hemocytes infected with PaV1 virusPhoto credit: Jeff Shields
Consequences of Sponge Die-off
Number of Lobsters / Den1 2 3 4 5 6 7 8 9 10 >10
Freq
uenc
y
0
10
20
30
40
50
Unimpacted Sites (n = 12)Impacted Sites (n = 13)
Lobster Den Occupancy Post Sponge Die-off
Aggregation of Juvenile Spiny Lobster• comparison of impacted & unimpacted sites after sponge die-off
Consequences of Sponge Die-offAggregation of Juvenile Spiny Lobster• time series at two sites before & after sponge die-off
Mea
n N
o. L
obst
ers
/ Den
0
2
4
6
8
July1999
May2000
April2001
June2001
Oct2007
Mar2008
July1999
May2000
April2001
June2001
Oct2007
Mar2008
Unimpacted Site: Burnt Point Impacted Site: KOA
SpongeDie-off
SpongeDie-off
Fewer sponges creates larger lobster aggregations …but does this also lead to higher prevalence of PaV1
disease due to increased contact transmission?
Freq
uenc
y
0
5
10
15
20
DiseasedLobster Alone
Diseased & HealthyTogether
N = 20
Shelter Competition Experiment: 1 Diseased Lobster3 Healthy Lobsters
2 shelters
Behringer, Butler & Shields Nature 2006
Sponge Die-Off Impacts on Lobster
% V
isib
ly D
isea
sed
(PaV
1)
0
5
10
15
20
25
Hem
olym
ph P
rote
in In
dex
0
5
10
15
20
% L
obst
ers
Inju
red
0
5
10
15
20
25
means + 1 sd
12 sites
13 sites
Num
ber o
f Lob
ster
s / S
helte
r
0
1
2
3
4
5
6
7
Lobs
ter A
bund
ance
(CPU
E)
0
10
20
30
Lobs
ter S
ize
(mm
CL)
0
10
20
30
40
50
60
13 sites12 sites
Unimpacted Impacted Unimpacted Impacted
Abundance
Den Sharing
Disease
Nutrition
Injuries
Size
Spatial Structure of Individual-Based Spiny
Lobster Recruitment Model
Individual-based Population Dynamics
MortalityMortalityMortalityMortality Shelter SelectionShelter SelectionShelter SelectionShelter Selection
GrowthGrowthGrowthGrowth EmigrationEmigrationEmigrationEmigrationSettlementSettlementSettlementSettlement
28 Day Loop Day Loop
PaV1 Disease
• empirically-basedprobability functions
• daily time step for eachindividual in model forspecified number of yrs
(e.g. ~ 10 million individualsin a 10 year simulation)
Spiny Lobster / SpongeSpatially Explicit IBM Model
Applications Thus Far:
• Everglades restoration: the effect of changing salinity on lobsters, sponges, & octocorals (in progress)
• Effect of a pathogenic virus and interactions with environmental change on lobster recruitment (in progress)
• Effect of spatial structure of nursery habitat • and postlarval supply on recruitment
• Effect of cyanobacteria blooms & sponge die-off on lobster recruitment
• Aggregation in juvenile lobsters: an examination of the group defense & guide-post hypotheses
Summary
• Impact of blooms on hard-bottom communities appears to be similar to that in 1991-1992, although bloom genesis is different
• Sponge die-off widespread in middle Florida Keys (~ 200 km2
area) and full recovery will take decades if no further blooms
• Sponge tolerance may be related to species-specific difference in filtration efficiencies?
• Ecosystem filtration capacity and habitat structure is greatly diminished in impacted areas, with a cascading loss of infaunal animals and crevice-dependent taxa, such as juvenile spiny lobster
• Lobster behavior appears to forestall increases in disease transmission expected in shelter-limited environment