community composition: A case

lameubiquityΜηχανική

21 Φεβ 2014 (πριν από 3 χρόνια και 8 μήνες)

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Sedimentation and coral reef
community composition: A case
study in Bocas del Toro,
Panamá



By Pete

Outline


Back Ground


Coral Reefs


Sedimentation and how it
effects corals


Bocas del Toro


Methods


Traps


Quadrates


Analysis


Results


Conclusion

Coral Reefs


Coral reefs are the most structurally complex and
taxonomically diverse marine ecosystems.


An estimated 58% of the world’s reefs are
threatened by human activities, resulting in a 30 to
60% reduction of reef species diversity


Excessive sedimentation is one of the most
prominent anthropogenic factors threatening reefs
globally

Sedimentation and Corals


Attenuates available light energy


At the individual level, sedimentation is associated
with;



less live coral,


lower coral growth rates,


greater abundance of branching forms,


decreased calcification,


decreased net productivity,


slower rates of reef accretion,


increased mucus production and an increase in
respiration

Sedimentation and Corals


Sedimentation can also have deleterious effects on
the population and community level of corals.


inhibiting population recruitment,


causing changes in the relative abundances of coral
species,


reducing substrate cover by live corals,


plummeting species richness and diversity


Sedimentation and eutrophication of tropical
coastal areas may contribute to fundamental
changes in community structure.

Methods

Gaubematic’ 3000 sediment

trap
trap



Depth of 13.5m

Buoy

Trap 1

Trap 2

Trap 3

2 Cinder Blocks

1.5m

0.3m

0.5m

0.49m

0.49m

0.49m

5m

5m

Surface of Water

Transects with Percent Cover
Quadrat

0m

Quadrat

Transect

5m

10m

Transects with Percent Cover
Quadrat

0m

40m

Quadrat

Transect

10m

Analysis


Averaged sedimentation rate with
corresponding community composition
data.


ANOVAs


OLS regressions



Results


Coral and Sedimentation Rate P=.048

Results


Algae and Sedimentation Rate P=.001

Results


Sponge and Sedimentation Rate P > .05

Conclusion


Sedimentation, along with other environmental
factors acts as a constraint on the coverage of
structure building corals, algae and sponge
complexes.


This is the first study that investigated the effects
of sedimentation on other taxa closely associated
with coral reefs, which can help us to disentangle
the complex interactions that drive species
richness, biodiversity and abundance on coral
reefs.

What now?



Submit paper to STRI and OTS,


Submit paper to “Journal of experimental
marine biology and ecology.”


Acknowledgments



Funded by STRI and OTS


Field Assistants


E. Salas


‘Sea’ McKean


K. Chrisler


Analysis and Write
-
up


A. Kerkhoff


B. Enquist


M. Weiser