Journal of Toxicology and Environmental Health, Part A, 2013
The BP Deepwater Horizon oil spill has great potential to negatively affect estuarine fish popula... more The BP Deepwater Horizon oil spill has great potential to negatively affect estuarine fish populations. In order to assess possible impacts of this event, a series of sublethal lab experiments were performed, using the economically and ecologically important species spotted seatrout (Cynoscion nebulosus). Larval and juvenile spotted seatrout were exposed to sublethal concentrations of high energy water accommodated fraction (HEWAF), chemically enhanced water accommodated fraction (CEWAF), or dispersant alone in an acute exposure. Response to exposure was evaluated with quantative polymerase chain reaction (qPCR) to examine expression of cytochrome P-4501A (CYP1A). Growth of larvae and juveniles over the duration of the experiment was measured as an index of physiological response. Our data showed that the different life stages respond differently to crude and dispersed oil, with larval spotted seatrout affected most by CEWAF, while juvenile spotted seatrout were affected to a greater extent by HEWAF. In both cases, the treatment with the highest CYP1A levels resulted in the greatest reductions in growth.
Effluent from septic systems can pollute groundwater and surface waters in coastal watersheds. Th... more Effluent from septic systems can pollute groundwater and surface waters in coastal watersheds. These effects are unknown for the highly urbanized central Indian River Lagoon (CIRL), Florida, where septic systems represent > 50% of wastewater disposal. To better understand these impacts, water quality was assessed along both canals and a tributary that drain into the CIRL. Dissolved nutrient concentrations were higher near septic systems than in natural areas. δ15N values of groundwater (+7.2‰), surface water (+5.5‰), and macrophytes (+9.7‰) were within the range for wastewater (>+3‰), as were surface water concentrations of the artificial sweetener sucralose (100 to 1700 ng/L) and fecal indicator bacteria density. These results indicate that septic systems are promoting eutrophication in the CIRL by contributing nutrient pollution to surface water via groundwater. This study demonstrates the need to reduce reliance on septic systems in urbanized coastal communities to improve water quality and subsequently mitigate harmful algal blooms.
Historically, extensive seagrass meadows were common throughout the Indian River Lagoon (IRL) in ... more Historically, extensive seagrass meadows were common throughout the Indian River Lagoon (IRL) in east central Florida, USA. Between 2011 and 2017, widespread catastrophic seagrass losses (~95%) occurred in the IRL following unprecedented harmful algal blooms (HABs), including persistent brown tides (Aureoumbra lagunensis). Little is known about how dissolved nutrients and chlorophyll a are related to light limitation or how biochemical factors, such as the elemental composition(C:N:P) and stable isotope signatures (d13C, d15N), of seagrasses within the IRL relate to coverage. Accordingly, we conducted a survey from2013 to 2015 at 20 sites to better understand these relationships. Results showed a negative correlation between DIN and salinity, indicating freshwater inputs as a DIN source. Seawater N:P ratios and chlorophyll a concentrations were higher in the urbanized, poorly-flushed northern IRL segments. Kd values were higher in the wet season and often exceeded seagrass light requirements (0.8 m1) for restoration, demonstrating light limitation.Species distribution varied by location. Halodule wrightii was ubiquitous, whereas Syringodium filiforme was not found in the northernmost segments. Thalassia testudinum was only present in the two southernmost segments that had the lowest TDN and highest light availability (Kd). Blade %N and %P also frequently exceeded critical values of 1.8% and 0.2%, respectively, especially in the northern segments. Further, d15N was positively correlated with ammonium, suggesting wastewater as a major N source. The d13C values indicated a trend of increasing light limitation from south to north, which helps explain the recent catastrophic loss of seagrasses in the northern IRL. Overall, elemental composition reflected high N-availability and seagrass species distributions were relatable to spatial trends in N and light limitation. For effective restoration, resource managers must reduce N-loading to the IRL to diminish HABs and increase light availability. Regular biochemical monitoring of seagrass tissue should also be implemented during restoration efforts.
Increased loadings of nitrogen (N) from fertilizers, top soil, sewage, and atmospheric deposition... more Increased loadings of nitrogen (N) from fertilizers, top soil, sewage, and atmospheric deposition are important drivers of eutrophication in coastal waters globally. Monitoring seawater and macroalgae can reveal long-term changes in N and phosphorus (P) availability and N:P stoichiometry that are critical to understanding the global crisis of coral reef decline. Analysis of a unique 3-decade data set for Looe Key reef, located offshore the lower Florida Keys, showed increased dissolved inorganic nitrogen (DIN), chlorophyll a, DIN:soluble reactive phosphorus (SRP) ratios, as well as higher tissue C:P and N:P ratios in macroalgae during the early 1990s. These data, combined with remote sensing and nutrient monitoring between the Everglades and Looe Key, indicated that the significant DIN enrichment between 1991 and 1995 at Looe Key coincided with increased Everglades runoff, which drains agricultural and urban areas extending north to Orlando, Florida. This resulted in increased P limitation of reef primary producers that can cause metabolic stress in stony corals. Outbreaks of stony coral disease, bleaching, and mortality between 1995 and 2000 followed DIN enrichment, algal blooms, and increased DIN:SRP ratios, suggesting that eutrophication interacted with other factors causing coral reef decline at Looe Key. Although water temperatures at Looe Key exceeded the 30.5 °C bleaching threshold repeatedly over the 3-decade study, the three mass bleaching events occurred only when DIN:SRP ratios increased following heavy rainfall and increased Everglades runoff. These results suggest that Everglades discharges, in conjunction with local nutrient sources, contributed to DIN enrichment, eutrophication, and increased N:P ratios at Looe Key, exacerbating P limitation, coral stress and decline. Improved management of water quality at the local and regional levels could moderate N inputs and maintain more balanced N:P stoichiometry, thereby reducing the risk of coral bleaching, disease, and mortality under the current level of temperature stress.
Energy exploration in the Gulf of Mexico (hereafter, Gulf) has resulted in the addition of numero... more Energy exploration in the Gulf of Mexico (hereafter, Gulf) has resulted in the addition of numerous oil and gas production platforms that create structurally complex habitat in an area otherwise dominated by barren mud/sand bottom. How these artificial structures affect fish populations is largely unknown, and there is ongoing debate regarding their value as surrogate habitats for ecologically and economically important reef fish species. Thus, the purpose of this study was to characterize trends in Red Snapper Lutjanus campechanus reproductive potential in the western Gulf at oil and gas platform reefs relative to reproductive potential at natural banks. Red Snapper (n = 1,585) were collected during 2013-2015 from standing platforms, decommissioned platform artificial reefs, and natural banks by using standardized vertical line gear. Comparisons of gonadosomatic index, male : female ratios, batch fecundity, annual fecundity, spawning frequency, and number of spawning-capable individuals indicated that Red Snapper reproductive biology was similar among natural bank, standing platform, and artificial reef habitats. These results suggest that in terms of reproductive output, fish inhabiting artificial reefs are functionally similar to similar-aged fish on natural banks. This work can be used to make informed management decisions and suggests that there are benefits to converting decommissioned platforms into designated artificial reefs. Future studies should consider site-specific characteristics, such as depth, vertical relief, and proximity to other structures, to elucidate how habitat characteristics may influence reproduction, ultimately improving future artificial reef deployments for fisheries enhancement in the western Gulf.
ABSTRACT The April 2010 Deepwater Horizon oil spill impacted shoreline marshes and estuaries in t... more ABSTRACT The April 2010 Deepwater Horizon oil spill impacted shoreline marshes and estuaries in the northern Gulf of Mexico (GOM). Spotted seatrout (Cynoscion nebulosus) are an estuarine resident, spring-summer spawning species in the GOM; thus, both adult and young-of-the-year fish were potentially exposed to oiled waters during 2010. We compared historical data on reproductive parameters of spotted seatrout from Barataria Bay Louisiana (1995 data) and the Mississippi Gulf coast (1999 data) to data collected from the same locations one year post-spill (2011). The Gonadosomatic Index of females from both areas was significantly lower in 2011 than pre-spill values. In 2011, delayed ovarian development and a lower percentage of fish in the actively spawning sub-phase were seen in Mississippi, and a higher percentage of non-reproductive fish was seen in Louisiana compared to pre-spill data. The prevalence of atretic vitellogenic oocytes was significantly higher in Mississippi and Louisiana fish in 2011, and spawning frequency was significantly reduced from every 4-5 days to every 13-38 days post-spill in both areas. These results indicate that relatively short-term, low level exposure to oiled waters can significantly impair fish reproductive parameters a year after the oil spill, which has population-level implications for many GOM fish species.
Journal of Toxicology and Environmental Health, Part A, 2013
The BP Deepwater Horizon oil spill has great potential to negatively affect estuarine fish popula... more The BP Deepwater Horizon oil spill has great potential to negatively affect estuarine fish populations. In order to assess possible impacts of this event, a series of sublethal lab experiments were performed, using the economically and ecologically important species spotted seatrout (Cynoscion nebulosus). Larval and juvenile spotted seatrout were exposed to sublethal concentrations of high energy water accommodated fraction (HEWAF), chemically enhanced water accommodated fraction (CEWAF), or dispersant alone in an acute exposure. Response to exposure was evaluated with quantative polymerase chain reaction (qPCR) to examine expression of cytochrome P-4501A (CYP1A). Growth of larvae and juveniles over the duration of the experiment was measured as an index of physiological response. Our data showed that the different life stages respond differently to crude and dispersed oil, with larval spotted seatrout affected most by CEWAF, while juvenile spotted seatrout were affected to a greater extent by HEWAF. In both cases, the treatment with the highest CYP1A levels resulted in the greatest reductions in growth.
Effluent from septic systems can pollute groundwater and surface waters in coastal watersheds. Th... more Effluent from septic systems can pollute groundwater and surface waters in coastal watersheds. These effects are unknown for the highly urbanized central Indian River Lagoon (CIRL), Florida, where septic systems represent > 50% of wastewater disposal. To better understand these impacts, water quality was assessed along both canals and a tributary that drain into the CIRL. Dissolved nutrient concentrations were higher near septic systems than in natural areas. δ15N values of groundwater (+7.2‰), surface water (+5.5‰), and macrophytes (+9.7‰) were within the range for wastewater (>+3‰), as were surface water concentrations of the artificial sweetener sucralose (100 to 1700 ng/L) and fecal indicator bacteria density. These results indicate that septic systems are promoting eutrophication in the CIRL by contributing nutrient pollution to surface water via groundwater. This study demonstrates the need to reduce reliance on septic systems in urbanized coastal communities to improve water quality and subsequently mitigate harmful algal blooms.
Historically, extensive seagrass meadows were common throughout the Indian River Lagoon (IRL) in ... more Historically, extensive seagrass meadows were common throughout the Indian River Lagoon (IRL) in east central Florida, USA. Between 2011 and 2017, widespread catastrophic seagrass losses (~95%) occurred in the IRL following unprecedented harmful algal blooms (HABs), including persistent brown tides (Aureoumbra lagunensis). Little is known about how dissolved nutrients and chlorophyll a are related to light limitation or how biochemical factors, such as the elemental composition(C:N:P) and stable isotope signatures (d13C, d15N), of seagrasses within the IRL relate to coverage. Accordingly, we conducted a survey from2013 to 2015 at 20 sites to better understand these relationships. Results showed a negative correlation between DIN and salinity, indicating freshwater inputs as a DIN source. Seawater N:P ratios and chlorophyll a concentrations were higher in the urbanized, poorly-flushed northern IRL segments. Kd values were higher in the wet season and often exceeded seagrass light requirements (0.8 m1) for restoration, demonstrating light limitation.Species distribution varied by location. Halodule wrightii was ubiquitous, whereas Syringodium filiforme was not found in the northernmost segments. Thalassia testudinum was only present in the two southernmost segments that had the lowest TDN and highest light availability (Kd). Blade %N and %P also frequently exceeded critical values of 1.8% and 0.2%, respectively, especially in the northern segments. Further, d15N was positively correlated with ammonium, suggesting wastewater as a major N source. The d13C values indicated a trend of increasing light limitation from south to north, which helps explain the recent catastrophic loss of seagrasses in the northern IRL. Overall, elemental composition reflected high N-availability and seagrass species distributions were relatable to spatial trends in N and light limitation. For effective restoration, resource managers must reduce N-loading to the IRL to diminish HABs and increase light availability. Regular biochemical monitoring of seagrass tissue should also be implemented during restoration efforts.
Increased loadings of nitrogen (N) from fertilizers, top soil, sewage, and atmospheric deposition... more Increased loadings of nitrogen (N) from fertilizers, top soil, sewage, and atmospheric deposition are important drivers of eutrophication in coastal waters globally. Monitoring seawater and macroalgae can reveal long-term changes in N and phosphorus (P) availability and N:P stoichiometry that are critical to understanding the global crisis of coral reef decline. Analysis of a unique 3-decade data set for Looe Key reef, located offshore the lower Florida Keys, showed increased dissolved inorganic nitrogen (DIN), chlorophyll a, DIN:soluble reactive phosphorus (SRP) ratios, as well as higher tissue C:P and N:P ratios in macroalgae during the early 1990s. These data, combined with remote sensing and nutrient monitoring between the Everglades and Looe Key, indicated that the significant DIN enrichment between 1991 and 1995 at Looe Key coincided with increased Everglades runoff, which drains agricultural and urban areas extending north to Orlando, Florida. This resulted in increased P limitation of reef primary producers that can cause metabolic stress in stony corals. Outbreaks of stony coral disease, bleaching, and mortality between 1995 and 2000 followed DIN enrichment, algal blooms, and increased DIN:SRP ratios, suggesting that eutrophication interacted with other factors causing coral reef decline at Looe Key. Although water temperatures at Looe Key exceeded the 30.5 °C bleaching threshold repeatedly over the 3-decade study, the three mass bleaching events occurred only when DIN:SRP ratios increased following heavy rainfall and increased Everglades runoff. These results suggest that Everglades discharges, in conjunction with local nutrient sources, contributed to DIN enrichment, eutrophication, and increased N:P ratios at Looe Key, exacerbating P limitation, coral stress and decline. Improved management of water quality at the local and regional levels could moderate N inputs and maintain more balanced N:P stoichiometry, thereby reducing the risk of coral bleaching, disease, and mortality under the current level of temperature stress.
Energy exploration in the Gulf of Mexico (hereafter, Gulf) has resulted in the addition of numero... more Energy exploration in the Gulf of Mexico (hereafter, Gulf) has resulted in the addition of numerous oil and gas production platforms that create structurally complex habitat in an area otherwise dominated by barren mud/sand bottom. How these artificial structures affect fish populations is largely unknown, and there is ongoing debate regarding their value as surrogate habitats for ecologically and economically important reef fish species. Thus, the purpose of this study was to characterize trends in Red Snapper Lutjanus campechanus reproductive potential in the western Gulf at oil and gas platform reefs relative to reproductive potential at natural banks. Red Snapper (n = 1,585) were collected during 2013-2015 from standing platforms, decommissioned platform artificial reefs, and natural banks by using standardized vertical line gear. Comparisons of gonadosomatic index, male : female ratios, batch fecundity, annual fecundity, spawning frequency, and number of spawning-capable individuals indicated that Red Snapper reproductive biology was similar among natural bank, standing platform, and artificial reef habitats. These results suggest that in terms of reproductive output, fish inhabiting artificial reefs are functionally similar to similar-aged fish on natural banks. This work can be used to make informed management decisions and suggests that there are benefits to converting decommissioned platforms into designated artificial reefs. Future studies should consider site-specific characteristics, such as depth, vertical relief, and proximity to other structures, to elucidate how habitat characteristics may influence reproduction, ultimately improving future artificial reef deployments for fisheries enhancement in the western Gulf.
ABSTRACT The April 2010 Deepwater Horizon oil spill impacted shoreline marshes and estuaries in t... more ABSTRACT The April 2010 Deepwater Horizon oil spill impacted shoreline marshes and estuaries in the northern Gulf of Mexico (GOM). Spotted seatrout (Cynoscion nebulosus) are an estuarine resident, spring-summer spawning species in the GOM; thus, both adult and young-of-the-year fish were potentially exposed to oiled waters during 2010. We compared historical data on reproductive parameters of spotted seatrout from Barataria Bay Louisiana (1995 data) and the Mississippi Gulf coast (1999 data) to data collected from the same locations one year post-spill (2011). The Gonadosomatic Index of females from both areas was significantly lower in 2011 than pre-spill values. In 2011, delayed ovarian development and a lower percentage of fish in the actively spawning sub-phase were seen in Mississippi, and a higher percentage of non-reproductive fish was seen in Louisiana compared to pre-spill data. The prevalence of atretic vitellogenic oocytes was significantly higher in Mississippi and Louisiana fish in 2011, and spawning frequency was significantly reduced from every 4-5 days to every 13-38 days post-spill in both areas. These results indicate that relatively short-term, low level exposure to oiled waters can significantly impair fish reproductive parameters a year after the oil spill, which has population-level implications for many GOM fish species.
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