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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.

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Presentation on theme: "Funded by Sea Grant Evaluation of the Effects of Sedimentation and Nutrients on Coral and the Long Term Monitoring of Recovery after Environmental Stress."— Presentation transcript:

1 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)

2 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 ?

3 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.

4 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.

5 Methodology The Mayagüez-Añasco watershed was selected due to the high sedimentation and nutrient impact present in the area.

6 Methodology The physiography, bathymetry, sediment texture and composition, and sedimentary facies in the area were characterized.

7 Methodology Characterization of reef areas

8 Methodology

9

10 Total Coral Cover

11 Coral cover by species

12 Methodology: A set of locations in Mayagüez and Añasco bays were chosen to provide a variety of conditions consistent with the goals of this project. MN MI AL EN

13 Coral Transplantation Thirteen coral species were studied. Colcophyllia natans (Cln) Dichocoenia stokessi (Dis) Diploria labyrinthiformis (Dpl) Diploria strigosa (Dps) Dendrogyra cylindrus (Dyc) Madracis decactis (Mad) Meandrina meandrites (Mem) Montastrea annularis (Mna) Montastrea cavernosa (Mnc) Porites asteroides (Pra) Porites porites (Prp) Siderastrea sideria (Sds) Undaria (Agaricia) agaricites (Aga) Species were selected base on their coral cover and number of colonies present.

14 Coral Transplantation Cementing coral to slab Finished slab & monitor stake

15 Coral from Escollo Negro are transplanted to: Manchas north Sewer reef Algarrobo Control slab transplant at Escollo Negro MN MI AL EN Transplant pattern: Healthy environment changed to impacted environment

16 MN MI AL EN Transplant pattern: Sediment & Nutrient stressed corals are given clean water environment. The environment has been “cleaned up.” Manchas Norte Manchas Interiores Algarrobo corals transplanted to Escollo Negro

17 From Manchas North slab ID - EN 92 From Manchas North slab ID - EN 47 From Manchas Interiores 8 slab ID - EN 50 From Manchas Interiores 8 slab ID - EN 62 From Algarrobo slab ID - EN 88 From Algarrobo slab ID - EN 83 Escollo Negro control - slab ID - EN 189 Escollo Negro control - slab ID - EN 188 Escollo Negro control - slab ID - EN 69 Escollo Negro control - slab ID - EN 49 To Manchas North slab ID - MN 45 To Manchas North slab ID - MN 95 To Manchas North slab ID - MN 73 To Manchas North slab ID – MN 65 To Manchas Interiores 8 slab ID - MI 26 To Manchas Interiores 8 slab ID - MI 187 To Manchas Interiores 8 slab ID - MI 80 To Manchas Interiores 8 slab ID - MI 16 To Algarrobo slab ID - AL 55 To Algarrobo slab ID - AL 77 To Algarrobo slab ID - AL 31 To Algarrobo slab ID - AL 66 Total of Transplants “clean” to “stressed” “stressed” to “clean” Average: 12 colonies per slab

18 Time Line added to each Transplanted Coral All corals stained with Alizarin Red-S at the time of transplantation

19 Measurements of Sedimentation Inputs Sediment traps were place in all locations Load-Texture-Composition

20 Measurements of water temperature Thermometers were place in all locations

21 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.

22 Monitoring: Every coral in each slab inspected bi-monthly EN 50 From Manchas Interiores 8 to Escollo Negro. From: Feb To: Oct. 2002

23 Monitoring: Changes in coral growth and health recorded Al 55 From Escollo Negro to Algarrobo

24 Harvesting: After two years samples of the transplanted corals were collected to measure: Coral growth rate before and after transplantation Trace elements and stable isotopes in skeletons Other… A minimum number of corals were sacrificed. Most samples consisted of 20% of the mass of the coral skeleton.

25 SUMARY of Results: Coral Mortality CF SITE SLAB Transplanted CF Remain LOST Manchas North MI Algarrobo Clean site (EN) to impacted sites: “clean” to “stressed” From: 139 coral colonies transplanted : 11 colonies lost by concrete failure

26 SUMARY of Results: Coral Mortality CF SITE SLAB Transplanted CF Remain LOST % Site % Manchas North MI Algarrobo Clean site (EN) to impacted sites: “clean” to “stressed” From: 139 coral colonies transplanted : 20 colonies died during the next two years (mostly because of algal overgrowth)

27 SUMARY of Results: Coral Mortality Siderastrea siderea Montastrea cavernosa Colpophyllia natans Porites asteroides Porites porites From: 139 coral colonies transplanted 9 colonies had measurable increase in size From Clean site (EN) to impacted sites: “clean” to “stressed”

28 SUMARY of Results: Coral Mortality SITE SLAB Transplanted CF Remain LOST % Site % Control “Clean” site to “clean” site (EN): CONTROL 49 coral colonies transplanted as “control” : 3 colonies lost by concrete failure 2 colonies lost during the next two years (coral grazers)

29 SUMARY of Results: Coral Mortality SITE SLAB Transplanted CF Remain LOST % Site % From Manchas Norte From MI From Algarrobo Impacted sites to clean site (EN): “stressed” to “clean” 48 coral colonies transplanted to the “clean” site : 1 colony lost by concrete failure 1 colony died during the next two years Manchas Norte samples INVALIDATED due to changes in the transplantation procedure.

30 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.

31 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

32 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.

33 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.

34 Coral Growth Rates X-rays were taken of each slab. 12 species At least two species per site (replicates)

35 Coral Growth Rates X-rays were scanned and digitally manipulated to enhance high and low density variations and measure the coral bands.

36 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)

37 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)

38 Coral Growth Gates (cm/yr) Mna 0.5 Mnc 0.3 Sds 0.5 Pra 0.5 Mna 0.6 Mnc 0.4 Sds 0.3 Pra 0.4 Mna 0.6 Mnc 0.5 Sds 0.4 Pra 0.3 Mna 0.6 Mnc 0.5 Sds 0.5 Pra 0.3 MN MI AL EN

39 Coral Growth Rates EN188 From EN to EN - Control Slab Porites porites Transplantation did not caused significant changes in the coral growth rate. cm TRANSPLANTATION time

40 Coral Growth Rates “Clean” to “stressed” sites Montastrea cavernosa TRANSPLANTATION EN EN to EN Control Growth rate either remain the same or increased !

41 Coral Growth Rates “Clean” to “stressed” sites Porites asteroides TRANSPLANTATION EN EN to EN Control Growth rate decreased.

42 Coral Growth Rates “Stressed” to “Clean” sites Montastrea annularis No significant changes visible From AL to En rate increased slightly ? TRANSPLANTATION From EN “ Controls”From ALFrom MI 8From MN

43 Coral Growth Rates “Stressed” to “Clean” sites Montastrea cavernosa No significant changes visible From MI-8 to En rate increased slightly ? From EN “ Controls”From ALFrom MI 8From MN

44 Sediment Traps Laboratory analyses XRD analysis (minerals, pesticides, chemicals) Composition analysis (organics, carbonate, terrigenous) Grain size distribution Average (yearly and monthly) sediment collection

45 Sediment Traps Laboratory analyses XRD analysis (minerals, pesticides, chemicals) Composition analysis (organics, carbonate, terrigenous) Grain size distribution Average (yearly and monthly) sediment collection

46 Sediment Traps Laboratory analyses XRD analysis (minerals, pesticides, chemicals) Composition analysis (organics, carbonate, terrigenous) Grain size distribution Average (yearly and monthly) sediment collection Grain Size Analysis for Escollo Negro

47 Sediment Traps Laboratory analyses XRD analysis (minerals, pesticides, chemicals) Composition analysis (organics, carbonate, terrigenous) Grain size distribution Average (yearly and monthly) sediment collection Suspended Sediment concentration -Surface Suspended Sediment concentration -Deep Total weight of sediment collected

48 Still to do: Thermometry in Corals (Calibrations) Temperature records Trace elements (Sr/Ca U/Ca Mg/Ca Ba/Ca) Stable Isotopes (O and C)

49 Conclusions: (Preliminary) Significant differences in coral cover between impacted vs. non impacted sites (up to 10%). Successful transplantation (7% loss by concrete failure). Significant loss of colonies moved to impacted sites (14 -18%). 4% of the colonies moved to non-impacted sites died (coral grazers, transplantation procedure ?). Most of the coral loss at impacted sites were primarily affected by overgrowth by turf algae. Siderastrea siderea, Montastrea cavernosa, Colpophyllia natans, Porites asteroides, and Porites porites showed resistance to stress.

50 Conclusions: (Preliminary) Similar coral growth rates between impacted vs. non- impacted areas. Transplantation procedure did not influenced the growth rates (control colonies). Statistics needed to explore differences in growth rate between sites and before and after transplantations. Seasonal variability in terrigenous vs. carbonate sedimentation at Escollo Negro. Seasonal and event driven variability in sedimentation input into the bay (redistribution). More to come ……..

51 Wilson R. Ramírez, 1 Jack Morelock, 2 Further information on the development of the results will be available at: PREGUNTAS ? QUESTIONS ? 1 Geology Department University of Puerto Rico at Mayagüez, P.O. Box 9017, Mayagüez, PR Department of Marine Sciences University of Puerto Rico at Mayagüez, P.O. Box 908, Lajas, PR Evaluation of the Effects of Sedimentation and Nutrients on Coral and the Long Term Monitoring of Recovery after Environmental Stress


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