An Examination of Hurricane Joaquin’s Impact on the Red...
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ABSTRACT INTRODUCTION CONCLUSIONS REFERENCES An Examination of Hurricane Joaquin’s Impact on the Red Mangrove Prop Root Biota of Oyster Pond in San Salvador Lauren Dunn, Ashlyn Pack, Alex Schwartz, Emily Sherman Dr. Dawn Ford and Jalana Abernathy B.S. METHODS RESULTS Observed Species Pre Hurricane Ford and Abernathy Post Hurricane Group Observations 2014 Average Percent Coverage Post Hurricane 2016 Isognomon alatus X X 9% Pinctada longisquamosa X X 10.3% Acetabularia calyculus X X 48.7% Batophora oerstedii X 60.7% Acetabularia crenulata X X 48.7% Eggsacks X 10% unknown hydroid X X 12.5% Cladophoropsis macromeres X Microdictyon marinum X Spyridia spp. X Batillaria minima X 2.5% Figure 1 Table 1 Acetabularia calyculus Acetabularia crenulata Figure 2 Figure 4 Figure 3 Black Mangrove Oysters Scaly Pearl Oysters Our research was conducted in Oyster Pond on San Salvador Island, Bahamas, to study Hurricane Joaquin’s impact on the biota of red mangrove (Rhizophora mangle) prop roots, with a focus on macroalgae and invertebrates. We hypothesized that there would be a decrease in the number and variety of organisms attached to the mangrove prop roots. Two transect lines were used to observe 16 samples using a 0.25 m2 quadrat to study the biota. Surface water grab samples were also collected to analyze water chemistry. Previous data for pH, salinity, and nutrients (nitrate, nitrite, and ammonia) showed little to no change in water chemistry 6 months after the hurricane. The dominant invertebrate species found on the prop roots was the black mangrove oyster (Isognonzen alatus) which contrasts with previous studies reporting the burnt mussel (Brachiodontes exastas) as the dominant species. Dominant macroalgae on the prop roots were Batophora oerstedii and Acetabularia (crenulata and calyculus), and previous studies reported a larger variety of macroalgae with a more even distribution. This study provides evidence that the red mangrove prop root biota is recovering, and is currently less diverse and less abundant than pre-hurricane conditions. San Salvador is a small outer island (See Figure 1) that was devastated by Hurricane Joaquin in October 2015. When a hurricane advances over an island, severe damage occurs to the terrestrial ecosystems and coastal communities. The results of hurricane damage depend on the hurricane’s intensity, velocity, diameter, and protection provided by topographical features (Tanner et al., 1991). Although there has been little research done on San Salvador’s interior ponds regarding the red mangroves, Doyle et al. (1992) found that a plethora of studies document hurricane effects on other islands and land masses. They state that mangrove species are susceptible and vulnerable to hurricane disturbances. The hurricane effects are what inspired our research in San Salvador. The objective of our study was to compare Rhizophora mangle prop roots pre- and post-hurricane Joaquin to see if there was a change in biota. Using measuring tape, Ziploc bags, a 0.25m 2 quadrat, orange flagging tape, and a GoPro, our group used transects to survey the red mangrove prop roots. We flagged off every 5 meters along the edge of the pond for 40 meters from each side of the entrance (Figure 5), and took a visual survey of the species present on the roots, took photographs for reference, and collected samples of the visible algae. This process was done for each flag , giving us 16 total samples. As part of our visual survey we determined the percent coverage of each species (algae and invertebrates). Figure 5 Our observations noted that there was less variety in macroalgae, and the roots were more dominated by Scaly Pearl Oysters and Black Mangrove Oysters (see Figure 3). The overall coverage of each observed root (or set of roots) was lower than the previous observations recounted to us by Dr. Ford and Jalana Abernathy. Table 1 demonstrates a visual comparison between our observations and the observations of Dr. Ford and Jalana Abernathy as well as the average percent coverage of each species observed/documented in our 2016 study. Pictured below is also a visual comparison of the two observed species of Acetabularia (Figure 2). Our observations determined no major changes in the number of species observed; however, we found that there was a significant change in the bivalve species as Black Mangrove Oysters heavily dominated while no Burnt Mussels were observed. This contrasts with data found in 2005-2007 by Cole et al. where Oyster Pond was dominated by Burnt Mussels. The algae species varied slightly, but the change was not significant in this study. Our data shows some parallels with the observations of Cole et al. where they found smaller changes in the biota of Oyster Pond post-hurricane when compared to the massive changes in other ponds like Little Granny Pond. It is hypothesized that Oyster Pond has some natural protection from the hurricane’s damaging effects, and more research could be done in the future on the biota of other sections of prop-roots in the pond. Pictured below are some photographs of the visual changes of the pond (Figure 4). The before photos are courtesy of Dr. Ford and Jalana Abernathy while the after photos were taken by Alex Schwartz during our research of the pond. Cole, Eric et al. 2005-2007. “The Effect of Hurricane Activity on Scaly Pearl Oysters, Pinctada longisquamosa, in Two Dissimilar Island Marine Ponds on San Salvador Island, Bahamas.” Proceedings of the Eleventh Symposium on the Natural History of the Bahamas. 79-79. Doyle, T. W. et al. 1995. “Wind Damage Effects of Hurricane Andrew on Mangrove Communities Along the Southwest Coast of Florida, USA.” Journal of Coastal Research, 159–168. Ford, Dawn and Jalana Abernathy. 2014-2015. “Biotic Survey of Reckley Hill, Crescent, and Oyster Ponds: Preliminary Findings.” Littler, Diane et al. 1989. “Marine Plants of the Caribbean: A Field Guide from Florida to Brazil.” Smithsonian Institution Press. Rothfus, Erin A. 2012. “Water Quality Monitoring of San Salvadorian Inland Lakes.” Proceedings of the Eleventh Symposium on the Natural History of the Bahamas and Other Carbonate Regions. Tanner, E. V. et al. 1991. “Hurricane Effects on Forest Ecosystems in the Caribbean.” Biotropica 23(4): 513–521.
Transcript of An Examination of Hurricane Joaquin’s Impact on the Red...
ABSTRACT
INTRODUCTION
CONCLUSIONS
REFERENCES
An Examination of Hurricane Joaquin’s Impact on the Red Mangrove Prop Root Biota of Oyster Pond in San Salvador
Lauren Dunn, Ashlyn Pack, Alex Schwartz, Emily Sherman
Dr. Dawn Ford and Jalana Abernathy B.S.
METHODS
RESULTS
Observed Species Pre Hurricane
Ford and Abernathy
Post Hurricane Group Observations
2014
Average Percent Coverage Post
Hurricane 2016
Isognomon alatus X X 9%
Pinctada longisquamosa X X 10.3%
Acetabularia calyculus X X 48.7%
Batophora oerstedii X 60.7%
Acetabularia crenulata X X 48.7%
Eggsacks X 10%
unknown hydroid X X 12.5%
Cladophoropsis macromeres X
Microdictyon marinum X
Spyridia spp. X
Batillaria minima X 2.5%
Batophera
oerstedii
Figure 1
Table 1
Acetabularia
calyculus
Acetabularia
crenulata
Figure 2
Figure 4
Figure 3
Black Mangrove Oysters
Scaly Pearl Oysters
Our research was conducted in Oyster Pond on San Salvador Island, Bahamas, to study Hurricane Joaquin’s impact on the biota of red mangrove (Rhizophora mangle) prop roots, with a focus on macroalgae and invertebrates. We hypothesized that there would be a decrease in the number and variety of organisms attached to the mangrove prop roots. Two transect lines were used to observe 16 samples using a 0.25 m2 quadrat to study the biota. Surface water grab samples were also collected to analyze water chemistry. Previous data for pH, salinity, and nutrients (nitrate, nitrite, and ammonia) showed little to no change in water chemistry 6 months after the hurricane. The dominant invertebrate species found on the prop roots was the black mangrove oyster (Isognonzen alatus) which contrasts with previous studies reporting the burnt mussel (Brachiodontes exastas) as the dominant species. Dominant macroalgae on the prop roots were Batophora oerstedii and Acetabularia (crenulata and calyculus), and previous studies reported a larger variety of macroalgae with a more even distribution. This study provides evidence that the red mangrove prop root biota is recovering, and is currently less diverse and less abundant than pre-hurricane conditions.
San Salvador is a small outer island (See Figure 1) that was devastated by Hurricane Joaquin in October 2015. When a hurricane advances over an island, severe damage occurs to the terrestrial ecosystems and coastal communities. The results of hurricane damage depend on the hurricane’s intensity, velocity, diameter, and protection provided by topographical features (Tanner et al., 1991). Although there has been little research done on San Salvador’s interior ponds regarding the red mangroves, Doyle et al. (1992) found that a plethora of studies document hurricane effects on other islands and land masses. They state that mangrove species are susceptible and vulnerable to hurricane disturbances. The hurricane effects are what inspired our research in San Salvador. The objective of our study was to compare Rhizophora mangle prop roots pre- and post-hurricane Joaquin to see if there was a change in biota.
Using measuring tape, Ziploc bags, a 0.25m2 quadrat, orange flagging tape, and a GoPro, our group used transects to survey the red mangrove prop roots. We flagged off every 5 meters along the edge of the pond for 40 meters from each side of the entrance (Figure 5), and took a visual survey of the species present on the roots, took photographs for reference, and collected samples of the visible algae. This process was done for each flag , giving us 16 total samples. As part of our visual survey we determined the percent coverage of each species (algae and invertebrates).
Figure 5
Our observations noted that there was less variety in macroalgae, and the roots were more dominated by Scaly Pearl Oysters and Black Mangrove Oysters (see Figure 3). The overall coverage of each observed root (or set of roots) was lower than the
previous observations recounted to us by Dr. Ford and Jalana Abernathy. Table 1 demonstrates a visual comparison between our observations and the observations of Dr. Ford and Jalana Abernathy as well as the average percent coverage of
each species observed/documented in our 2016 study. Pictured below is also a visual comparison of the two observed species of Acetabularia (Figure 2).
Our observations determined no major changes in the number of species observed; however, we found that there was a significant change in the bivalve species as Black Mangrove Oysters heavily dominated while no Burnt Mussels were observed. This contrasts with data found in 2005-2007 by Cole et al. where Oyster Pond was dominated by Burnt Mussels. The algae species varied slightly, but the change was not significant in this study. Our data shows some parallels with the observations of Cole et al. where they found smaller changes in the biota of Oyster Pond post-hurricane when compared to the massive changes in other ponds like Little Granny Pond. It is hypothesized that Oyster Pond has some natural protection from the hurricane’s damaging effects, and more research could be done in the future on the biota of other sections of prop-roots in the pond. Pictured below are some photographs of the visual changes of the pond (Figure 4). The before photos are courtesy of Dr. Ford and Jalana Abernathy while the after photos were taken by Alex Schwartz during our research of the pond.
Cole, Eric et al. 2005-2007. “The Effect of Hurricane Activity on Scaly Pearl Oysters, Pinctada longisquamosa, in Two Dissimilar Island Marine Ponds on San Salvador Island, Bahamas.” Proceedings of the Eleventh Symposium on the Natural History of the Bahamas. 79-79. Doyle, T. W. et al. 1995. “Wind Damage Effects of Hurricane Andrew on Mangrove Communities Along the Southwest Coast of Florida, USA.” Journal of Coastal Research, 159–168. Ford, Dawn and Jalana Abernathy. 2014-2015. “Biotic Survey of Reckley Hill, Crescent, and Oyster Ponds: Preliminary Findings.” Littler, Diane et al. 1989. “Marine Plants of the Caribbean: A Field Guide from Florida to Brazil.” Smithsonian Institution Press. Rothfus, Erin A. 2012. “Water Quality Monitoring of San Salvadorian Inland Lakes.” Proceedings of the Eleventh Symposium on the Natural History of the Bahamas and Other Carbonate Regions. Tanner, E. V. et al. 1991. “Hurricane Effects on Forest Ecosystems in the Caribbean.” Biotropica 23(4): 513–521.
