Funded by Sea Grant Evaluation of the Effects of Sedimentation and Nutrients on Coral and the Long Term Monitoring of Recovery after Environmental Stress Wilson R. Ramírez 1 Jack Morelock 2 1 Department of Geology University of Puerto Rico at Mayagüez 2 Department of Marine Sciences University of Puerto Rico at Mayagüez Marine Sciences (Preliminary Report) (Preliminary Report)
Evaluation of the Effects of Sedimentation and Nutrients on Coral and the Long Term Monitoring of Recovery after Environmental Stress. (Preliminary Report). Wilson R. Ramírez 1 Jack Morelock 2. 1 Department of Geology University of Puerto Rico at Mayagüez - PowerPoint PPT Presentation
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Funded by Sea Grant
Evaluation of the Effects of Sedimentation and Nutrients on Coral
and the Long Term Monitoring of Recovery after Environmental Stress
Wilson R. Ramírez 1 Jack Morelock 2
1 Department of Geology University of Puerto Rico at Mayagüez
2 Department of Marine Sciences University of Puerto Rico at Mayagüez
Marine Sciences
(Preliminary Report)(Preliminary Report)
Questions :o How can we quantify the effects of terrigenous
sediment and nutrient stress on corals in their natural environment ?
o Is it worth to establish more strict regulations ($$$) on sedimentation / nutrient inputs to reefs ?
o Can reefs recover from the terrigenous sediment and nutrient stress they have been exposed to ?
Possible alternatives to answer these questions :
1. Study and compare reef systems in impacted vs. non-impacted areas.
2. Develop and apply better regulations for land development and sewage management to study how reef systems respond.
3. Move impacted corals to clean areas and monitor their responses.
Objectives :
• Measure recovery of coral cover after reduction in sediment/nutrient stress.
• Measure the impact on “healthy” corals moved into stress conditions.
• Determine which species are the more and less resistant to and nutrient sediment stress.
• Produce information that will lead to better ability to manage reef systems.
MethodologyThe Mayagüez-Añasco watershed was selected due to the high sedimentation and nutrient impact present in the area.
MethodologyThe physiography, bathymetry, sediment texture and composition, and sedimentary facies in the area were characterized.
Methodology
Characterization of reef areas
Methodology
Methodology
Total Coral Cover
Coral coverby species
Methodology:A set of locations in Mayagüez and Añasco bays were chosen to provide a variety of conditions consistent with the goals of thisproject.
Species were selected base on their coral cover and number of colonies present.
Coral Transplantation
Cementing coral to slab
Finished slab & monitor stake
Coral from Escollo Negro are transplanted to:
Manchas northSewer reefAlgarrobo
Control slab transplant at Escollo Negro
MNMN
MIMI
ALAL
ENEN
Transplant pattern:Healthy environment changed to impacted
environment
MNMN
MIMI
ALAL
ENEN
Transplant pattern:Sediment & Nutrient stressed corals are given clean water environment. The environment has been “cleaned up.”
Manchas NorteManchas InterioresAlgarrobo
corals transplanted to Escollo Negro
From Manchas North slab ID - EN 92From Manchas North slab ID - EN 47
From Manchas Interiores 8 slab ID - EN 50From Manchas Interiores 8 slab ID - EN 62
From Algarrobo slab ID - EN 88From Algarrobo slab ID - EN 83
Escollo Negro control - slab ID - EN 189Escollo Negro control - slab ID - EN 188Escollo Negro control - slab ID - EN 69Escollo Negro control - slab ID - EN 49
To Manchas North slab ID - MN 45To Manchas North slab ID - MN 95To Manchas North slab ID - MN 73To Manchas North slab ID – MN 65
To Manchas Interiores 8 slab ID - MI 26To Manchas Interiores 8 slab ID - MI 187To Manchas Interiores 8 slab ID - MI 80To Manchas Interiores 8 slab ID - MI 16
To Algarrobo slab ID - AL 55To Algarrobo slab ID - AL 77To Algarrobo slab ID - AL 31To Algarrobo slab ID - AL 66
Total of Transplants
“clean” to “stressed”“stressed” to “clean”
Average: 12 colonies per slab
Time Line added to each Transplanted Coral
All corals stained with Alizarin Red-S at the time of transplantation
Measurements of Sedimentation Inputs
Sediment traps were place in all locations
Load-Texture-Composition
Measurements of water temperature
Thermometers were place in all locations
Bi-monthly Monitoring for two years
Photographs and notes describing the status of the corals.
Sediments in traps collected bi-monthly.
Continuous (every 2 hours) temperature measurements for two years.
Monitoring:Every coral in each slab inspected bi-monthly
EN 50EN 50From Manchas Interiores 8 to Escollo Negro.
From: Feb. 2002To: Oct. 2002
Monitoring:Changes in coral growth and health recorded
Al 55From Escollo Negro to Algarrobo
Harvesting:• After two years samples of the transplanted
corals were collected to measure:Coral growth rate before and after transplantationTrace elements and stable isotopes in skeletonsOther…
A minimum number of corals were sacrificed. Most samples consisted of 20% of the mass of the coral skeleton.
SUMARY of Results: Coral Mortality
SITE SLAB Transplanted CFCF Remain LOSTManchas North 45 12 12 0
2020 colonies died during the next two years colonies died during the next two years((mostly because of algal overgrowthmostly because of algal overgrowth))
49 49 coral colonies transplanted as “control” :coral colonies transplanted as “control” :
33 colonies lost by concrete failure colonies lost by concrete failure22 colonies lost during the next two years colonies lost during the next two years (coral grazers)
SUMARY of Results: Coral Mortality
SITE SLAB Transplanted CF Remain LOST % Site %FromManchas 47 12 1 7 4 36Norte 92 12 2 10 83 61
From MI-8 50 12 1 11 0 062 12 12 0 0 0
From Algarrobo 83 11 11 0 088 12 11 1 8 4
Impacted sites to clean site (EN): “stressed” to “clean”
48 48 coral colonies transplanted to the “clean” site :coral colonies transplanted to the “clean” site :1 1 colony lost by concrete failure colony lost by concrete failure 11 colony died during the next two years colony died during the next two years
Manchas Norte samples Manchas Norte samples INVALIDATEDINVALIDATED due to changes in the transplantation procedure. due to changes in the transplantation procedure.
General Conclusions on Slab Monitoring
• Concrete slabs were quickly covered with turf algae mats at the stressed sites.
• Most of the coral loss at these sites seemed to be due to overgrowth of the coral colonies by turf algae.
• Most loss of coral colonies was within the first few months then reduction of living colonies remaining was slow.
General conclusions on Slab Monitoring
• Porites asteroides and Montastrea cavernosa showed significant growth when moved from “stress” into a “clean” environment.
• Montastraea cavernosa colonies also showed active budding when moved from “stress” into “clean” environment.
EN 83
EN 62
General Conclusions on Slab Monitoring
• Montastrea annularis can keep a slow growing rate in sediment-stressed reefs.
Porites asteroides and Siderastrea sidere, showed more growth than Montastrea cavernosa when moved “stress” into “clean” environment.
Coral Growth Rates• Alizarin Red-S Line was identified in the coral slabs.
• This line represent the time 0 or the time of the transplantation.
Coral Growth Rates• X-rays were taken of each slab.
12 species At least two species per site (replicates)
Coral Growth Rates• X-rays were scanned and digitally manipulated to
enhance high and low density variations and measure the coral bands.
Coral Growth Rates• Bands are measured before and after
transplantation using the Alizarin Red-S line as a reference.
• A set of 2 bands (high & low density) represent 1 year.
• 4 years measured (2 years before and 2 years after transplantation)
Coral Growth Rates• Bands are measured before and after
transplantation using the Alizarin Red-S line as a reference.
• A set of 2 bands (high & low density) represent 1 year.
• 4 years measured (2 years before and 2 years after transplantation)