Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities

Renee K. Gruber, Ryan J. Lowe, James L. Falter

    Research output: Contribution to journalArticle

    Abstract

    Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing, including local hydrodynamics and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterized as having circulation that is predominantly tidally forced, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated reef platform with a spring tidal range exceeding 8 m. Nutrient fluxes were estimated using a one-dimensional control volume approach, combining flow measurements with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released 2.3 mmol m(-2) d(-1) of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on timescales of similar to minutes-hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.

    Original languageEnglish
    Pages (from-to)1921-1935
    Number of pages15
    JournalBiogeosciences
    Volume16
    Issue number9
    DOIs
    Publication statusPublished - 13 May 2019

    Cite this

    Gruber, Renee K. ; Lowe, Ryan J. ; Falter, James L. / Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities. In: Biogeosciences. 2019 ; Vol. 16, No. 9. pp. 1921-1935.
    @article{5e26691872ce47d0be3f78b1941287ee,
    title = "Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities",
    abstract = "Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing, including local hydrodynamics and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterized as having circulation that is predominantly tidally forced, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated reef platform with a spring tidal range exceeding 8 m. Nutrient fluxes were estimated using a one-dimensional control volume approach, combining flow measurements with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released 2.3 mmol m(-2) d(-1) of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on timescales of similar to minutes-hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.",
    keywords = "FREE AMINO-ACIDS, CORAL-REEF, ORGANIC NITROGEN, MASS-TRANSFER, INORGANIC NITROGEN, WATER VELOCITY, FLOW, PHOSPHORUS, LAGOON, FLAT",
    author = "Gruber, {Renee K.} and Lowe, {Ryan J.} and Falter, {James L.}",
    year = "2019",
    month = "5",
    day = "13",
    doi = "10.5194/bg-16-1921-2019",
    language = "English",
    volume = "16",
    pages = "1921--1935",
    journal = "Biogeosciences",
    issn = "1726-4170",
    publisher = "Copernicus Gesellschaft mbH",
    number = "9",

    }

    Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities. / Gruber, Renee K.; Lowe, Ryan J.; Falter, James L.

    In: Biogeosciences, Vol. 16, No. 9, 13.05.2019, p. 1921-1935.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities

    AU - Gruber, Renee K.

    AU - Lowe, Ryan J.

    AU - Falter, James L.

    PY - 2019/5/13

    Y1 - 2019/5/13

    N2 - Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing, including local hydrodynamics and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterized as having circulation that is predominantly tidally forced, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated reef platform with a spring tidal range exceeding 8 m. Nutrient fluxes were estimated using a one-dimensional control volume approach, combining flow measurements with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released 2.3 mmol m(-2) d(-1) of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on timescales of similar to minutes-hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.

    AB - Benthic fluxes of dissolved nutrients in reef communities are controlled by oceanographic forcing, including local hydrodynamics and seasonal changes in oceanic nutrient supply. Up to a third of reefs worldwide can be characterized as having circulation that is predominantly tidally forced, yet almost all previous research on reef nutrient fluxes has focused on systems with wave-driven circulation. Fluxes of dissolved nitrogen and phosphorus were measured on a strongly tide-dominated reef platform with a spring tidal range exceeding 8 m. Nutrient fluxes were estimated using a one-dimensional control volume approach, combining flow measurements with modified Eulerian sampling of waters traversing the reef. Measured fluxes were compared to theoretical mass-transfer-limited uptake rates derived from flow speeds. Reef communities released 2.3 mmol m(-2) d(-1) of nitrate, potentially derived from the remineralization of phytoplankton and dissolved organic nitrogen. Nutrient concentrations and flow speeds varied between the major benthic communities (coral reef and seagrass), resulting in spatial variability in estimated nitrate uptake rates. Rapid changes in flow speed and water depth are key characteristics of tide-dominated reefs, which caused mass-transfer-limited nutrient uptake rates to vary by an order of magnitude on timescales of similar to minutes-hours. Seasonal nutrient supply was also a strong control on reef mass-transfer-limited uptake rates, and increases in offshore dissolved inorganic nitrogen concentrations during the wet season caused an estimated twofold increase in uptake.

    KW - FREE AMINO-ACIDS

    KW - CORAL-REEF

    KW - ORGANIC NITROGEN

    KW - MASS-TRANSFER

    KW - INORGANIC NITROGEN

    KW - WATER VELOCITY

    KW - FLOW

    KW - PHOSPHORUS

    KW - LAGOON

    KW - FLAT

    U2 - 10.5194/bg-16-1921-2019

    DO - 10.5194/bg-16-1921-2019

    M3 - Article

    VL - 16

    SP - 1921

    EP - 1935

    JO - Biogeosciences

    JF - Biogeosciences

    SN - 1726-4170

    IS - 9

    ER -