Distribution of nutrients and chlorophyll across an equatorial reef region: Insights on coastal gradients
Hortência de Sousa Barroso
Isabelle de Oliveira Lima
Antonia Diana Alves Bezerra
Tatiane Martins Garcia
Tallita Cruz Lopes Tavares
Ravena Santiago Alves
Edmilson Ferreira de Souza Junior
Carlos Eduardo Peres Teixeira
Michael Barbosa Viana
Marcelo de Oliveira Soares
Abstract
We evaluate how the concentrations of inorganic nutrients and chlorophyll a vary in a heterogeneous area (Equatorial SW Atlantic), covering a gradient from stations closer to the coast to others more distant associated or not with turbid-zone reefs. Vertical temperature (27.9 ± 0.10 °C; mean ± standard deviation) and salinity (36.2 ± 0.14) profles showed that the water column is well mixed (0-30 m depth). The oligotrophic condition was marked by low concentrations of phosphate (0.30 ± 0.22 µM) and dissolved inorganic nitrogen (0.64 ± 0.74 µM). Moreover, dissolved reactive silicon (DSi) was low in most samples (< 2.0 µM), but higher (>10 µM) in nearshore stations, probably related to continental runoff and/or resuspension of the bottom sediments. The pelagic phytoplankton biomass indicated that chlorophyll a (0.25 ± 0.08 µg L-1) was low, positively correlated with light and negatively correlated with nutrients, indicating possible phytoplankton uptake. Chlorophyll a concentrations were lower in stations closer to the coast and higher in some stations near the reefs, indicating that the latter could be more prone to phytoplankton development and depletion of nutrients, especially DSi. Therefore, although oligotrophy is present along this coast, we found some unexpected heterogeneity of nutrient and chlorophyll a distributions, which were probably infuenced by benthic-pelagic coupling due to the presence of extensive reefs, sponge gardens (18-30 m depth), and the proximity to the coast. These results highlight the importance of understanding the heterogeneity of ocean productivity, especially in lesser known low-latitude areas, which showed distinct nutrient and chlorophyll a levels related to the occurrence of tropical reefs that are capable of supporting important fsh stocks and unique biological communities.
Barroso H.d.S., Lima I.d.O., Bezerra A.D.A., Garcia T.M., Tavares T.C.L., Alves R.S., Souza Junior E.F.d., Teixeira C.E.P., Viana M.B. and Soares M.d.O. (2022) Distribution of nutrients and chlorophyll across an equatorial reef region: Insights on coastal gradients. Ocean and Coastal Research 71(suppl 2): e23002. 10.1590/2675-2824071.22016hdsb
@article{Barroso2022,
Title = {Distribution of nutrients and chlorophyll across an equatorial reef region: Insights on coastal gradients},
Author = {Barroso, Hortência de Sousa and Lima, Isabelle de Oliveira and Bezerra, Antonia Diana Alves and Garcia, Tatiane Martins and Tavares, Tallita Cruz Lopes and Alves, Ravena Santiago and Souza Junior, Edmilson Ferreira de and Teixeira, Carlos Eduardo Peres and Viana, Michael Barbosa and Soares, Marcelo de Oliveira},
Editor = {},
Journal = {Ocean and Coastal Research},
Year = {2022},
Pages = {e23002},
Volume = {71},
Doi = {10.1590/2675-2824071.22016hdsb},
Abstract = {We evaluate how the concentrations of inorganic nutrients and chlorophyll a vary in a heterogeneous area (Equatorial SW Atlantic), covering a gradient from stations closer to the coast to others more distant associated or not with turbid-zone reefs. Vertical temperature (27.9 ± 0.10 °C; mean ± standard deviation) and salinity (36.2 ± 0.14) profles showed that the water column is well mixed (0-30 m depth). The oligotrophic condition was marked by low concentrations of phosphate (0.30 ± 0.22 µM) and dissolved inorganic nitrogen (0.64 ± 0.74 µM). Moreover, dissolved reactive silicon (DSi) was low in most samples (< 2.0 µM), but higher (>10 µM) in nearshore stations, probably related to continental runoff and/or resuspension of the bottom sediments. The pelagic phytoplankton biomass indicated that chlorophyll a (0.25 ± 0.08 µg L-1) was low, positively correlated with light and negatively correlated with nutrients, indicating possible phytoplankton uptake. Chlorophyll a concentrations were lower in stations closer to the coast and higher in some stations near the reefs, indicating that the latter could be more prone to phytoplankton development and depletion of nutrients, especially DSi. Therefore, although oligotrophy is present along this coast, we found some unexpected heterogeneity of nutrient and chlorophyll a distributions, which were probably infuenced by benthic-pelagic coupling due to the presence of extensive reefs, sponge gardens (18-30 m depth), and the proximity to the coast. These results highlight the importance of understanding the heterogeneity of ocean productivity, especially in lesser known low-latitude areas, which showed distinct nutrient and chlorophyll a levels related to the occurrence of tropical reefs that are capable of supporting important fsh stocks and unique biological communities.},
}
TY - JOUR
AU - Barroso, Hortência de Sousa
AU - Lima, Isabelle de Oliveira
AU - Bezerra, Antonia Diana Alves
AU - Garcia, Tatiane Martins
AU - Tavares, Tallita Cruz Lopes
AU - Alves, Ravena Santiago
AU - Souza Junior, Edmilson Ferreira de
AU - Teixeira, Carlos Eduardo Peres
AU - Viana, Michael Barbosa
AU - Soares, Marcelo de Oliveira
TI - Distribution of nutrients and chlorophyll across an equatorial reef region: Insights on coastal gradients
T2 - Ocean and Coastal Research
PY - 2022
SP - e23002
VL - 71
DO - 10.1590/2675-2824071.22016hdsb
AB - We evaluate how the concentrations of inorganic nutrients and chlorophyll a vary in a heterogeneous area (Equatorial SW Atlantic), covering a gradient from stations closer to the coast to others more distant associated or not with turbid-zone reefs. Vertical temperature (27.9 ± 0.10 °C; mean ± standard deviation) and salinity (36.2 ± 0.14) profles showed that the water column is well mixed (0-30 m depth). The oligotrophic condition was marked by low concentrations of phosphate (0.30 ± 0.22 µM) and dissolved inorganic nitrogen (0.64 ± 0.74 µM). Moreover, dissolved reactive silicon (DSi) was low in most samples (< 2.0 µM), but higher (>10 µM) in nearshore stations, probably related to continental runoff and/or resuspension of the bottom sediments. The pelagic phytoplankton biomass indicated that chlorophyll a (0.25 ± 0.08 µg L-1) was low, positively correlated with light and negatively correlated with nutrients, indicating possible phytoplankton uptake. Chlorophyll a concentrations were lower in stations closer to the coast and higher in some stations near the reefs, indicating that the latter could be more prone to phytoplankton development and depletion of nutrients, especially DSi. Therefore, although oligotrophy is present along this coast, we found some unexpected heterogeneity of nutrient and chlorophyll a distributions, which were probably infuenced by benthic-pelagic coupling due to the presence of extensive reefs, sponge gardens (18-30 m depth), and the proximity to the coast. These results highlight the importance of understanding the heterogeneity of ocean productivity, especially in lesser known low-latitude areas, which showed distinct nutrient and chlorophyll a levels related to the occurrence of tropical reefs that are capable of supporting important fsh stocks and unique biological communities.
ER -
