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Description:
Title:
Use of sucralose and caffeine as tracers of human waste in a coral reef ecosystem
Author(s):
Whitall, D.
Curtis, M.
Mason, A.
Dates of Publication:
2021
Abstract:
Over the past ten years, divers have noted a decrease in healthy coral cover and an increase in benthic algae in Vatia Bay, on the island of Tutuila, American Samoa. The cause for this is unknown, but one hypothesis is that nutrient pollution from the local village may be driving the coral decline. Excess nutrients (especially nitrogen and phosphorus) can impact corals directly by lowering fertilization success, and reducing both photosynthesis and calcification rates, or indirectly such as through stimulation of the growth of benthic algae. Declining coral health adversely affects the biodiversity of the Bay and likely decreases ecosystem services. The objectives of this study were to determine the nutrient status of Vatia Bay (i.e. are levels elevated) and attempt to use caffeine and sucralose as tracers to assess the potential importance of human waste to the nutrient budget of the system. Water samples were collected monthly at sixteen sites, selected using a stratified random design, for analysis of nitrate, nitrite, ammonium, urea, total nitrogen, orthophosphorus, total phosphorus, silica and salinity. These data confirm that nutrient concentrations are elevated in the Bay, when compared to territorial water quality standards (total nitrogen < 0.15 mg N/L; total phosphorus < 0.02 mg P/L). Land based contributions of phosphorus and reactive nitrogen can enter the environment from a variety of sources, but in Vatia the most likely sources are piggeries and septic systems. Analysis of water samples for tracers of human waste (caffeine and sucralose) confirmed that human derived nutrients are contributing to the nutrient budget of the Bay. Caffeine was detected in 82% of samples and sucralose was detected in 51% of samples, definitively confirming that human waste is reaching the Bay. Additionally, sucralose concentrations are significantly correlated with some nutrient constituents, including urea, a major component of waste. These data are useful not only to enhance the understanding of the role that anthropogenic nutrients play in the biodiversity and ecosystem health of the Bay, but also serve as an important “baseline” against which to measure future change.
Keywords:
Caffeine
Coral reef ecology
Coral reefs and islands
Corals
Nutrient pollution of water
Sucralose
Water quality
Local Corporate Name:
NOS (National Ocean Service)
NCCOS (National Centers for Coastal Ocean Science)
Format:
PDF
Type of Resource:
Journal Article
Note:
Over the past ten years, divers have noted a decrease in healthy coral cover and an increase in benthic algae in Vatia Bay, on the island of Tutuila, American Samoa. The cause for this is unknown, but one hypothesis is that nutrient pollution from the local village may be driving the coral decline. Excess nutrients (especially nitrogen and phosphorus) can impact corals directly by lowering fertilization success, and reducing both photosynthesis and calcification rates, or indirectly such as through stimulation of the growth of benthic algae. Declining coral health adversely affects the biodiversity of the Bay and likely decreases ecosystem services. The objectives of this study were to determine the nutrient status of Vatia Bay (i.e. are levels elevated) and attempt to use caffeine and sucralose as tracers to assess the potential importance of human waste to the nutrient budget of the system. Water samples were collected monthly at sixteen sites, selected using a stratified random design, for analysis of nitrate, nitrite, ammonium, urea, total nitrogen, orthophosphorus, total phosphorus, silica and salinity. These data confirm that nutrient concentrations are elevated in the Bay, when compared to territorial water quality standards (total nitrogen < 0.15 mg N/L; total phosphorus < 0.02 mg P/L). Land based contributions of phosphorus and reactive nitrogen can enter the environment from a variety of sources, but in Vatia the most likely sources are piggeries and septic systems. Analysis of water samples for tracers of human waste (caffeine and sucralose) confirmed that human derived nutrients are contributing to the nutrient budget of the Bay. Caffeine was detected in 82% of samples and sucralose was detected in 51% of samples, definitively confirming that human waste is reaching the Bay. Additionally, sucralose concentrations are significantly correlated with some nutrient constituents, including urea, a major component of waste. These data are useful not only to enhance the understanding of the role that anthropogenic nutrients play in the biodiversity and ecosystem health of the Bay, but also serve as an important “baseline” against which to measure future change.
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DOI:
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