Dissolved aluminium cycling in the northern, equatorial and subtropical gyre region of the Indian Ocean

Santos

et al. 2021

RICA

A zona portuária de Belém, situada no estuário Guajarino, abriga os portos de Belém, Terminal Petroquímico de Miramar e Porto de Outeiro. Neste sentido, este estudo buscou criar indicadores de qualidade da água, através da análise fatorial que reflitam as peculiaridades e a dinâmica da zona portuária de Belém. Foram feitas amostragens mensais de água ao longo dos anos de 2014 e 2016, em toda zona portuária, englobando os três. Os resultados foram submetidos a análise fatorial (AF) para criação do Indicador de Avaliação Padronizado (IAP), que classificou a qualidade das águas amostradas nas faixas péssima, ruim, regular, boa e ótima. Os resultados mostraram que 46,03% e 42,85% das amostras do porto de Belém ficaram classificadas como péssimas e ruins, respectivamente. O terminal de Miramar apresentou classificação péssima para 46,98% das amostras, e o porto de Belém concentrou 45,98% dessas amostras analisadas na faixa de qualidade ruim; por fim, o Porto de Outeiro também mostrou uma qualidade péssima para 52,58% das amostras. A AF possibilitou uma visão integrada dos dados, mostrando como os efeitos das atividades desenvolvidas ao longo da zona portuária de Belém influenciam a qualidade da água.

Section: Resultsunclassified

Indicador da qualidade da água através de análise fatorial: um estudo de caso na zona portuária de Belém, Amazônia, Brasil

Santos

et al. 2021

RICA

Deep Sea Research Part I: Oceanographic Research Papers

“…Other analysts have found consistently elevated Al values for the low nM level GEOTRACES standards (e.g. Resing et al, 2015;Singh et al, 2020). Daily precision for standards was on average 3.4% relative standard deviation (RSD) at 1 nM and 2.2% RSD at 20 nM.…”

Section: Methodsmentioning

confidence: 99%

Constraining the Solomon Sea as a source of Al and Mn to the Equatorial Undercurrent

Michael

Lacan²,

Buck³

et al. 2021

HighlightsAl and Mn are not significantly enriched during transit through the Solomon Sea.Fluxes of Al and Mn into and out of the Solomon Sea are almost equal.Al and Mn are elevated near continental shelves and margins in the Solomon Sea.Local enrichments must be balanced by boundary exchange and scavenging processes.Water exiting the Solomon Sea accounts for ca. half the flux of Al and Mn in the EUC.

“…Signatures of elevated Al due to sedimentary contribution is seen in ship-borne measurements (Grand et al, 2015;Singh et al, 2020). In fact, such measurements have shown that the South Equatorial Current separates DFe-rich oxygen-poor water of the northern IO from the DFe-poor oxygen-rich water of the southern tropical IO (Grand et al, 2015).…”

Section: Contribution Of Multiple Iron Sourcesmentioning

confidence: 97%

Importance of multiple sources of iron for the upper ocean biogeochemistry over the northern Indian Ocean

Banerjee

2022

Preprint

Abstract. Although the northern Indian Ocean (IO) is globally one of the most productive regions and receives dissolved iron (DFe) from multiple sources, there is no comprehensive understanding of how these different sources of DFe can impact upper ocean biogeochemical dynamics. Using an Earth system model with an ocean biogeochemistry component this study shows that atmospheric deposition is the most important source of DFe to the upper 100 m of the northern IO, contributing more than 50 % of the annual DFe concentration. Sedimentary sources are locally important in the vicinity of the continental shelves and over the southern tropical IO, away from high atmospheric depositions. While atmospheric deposition contributes to more than 10 % (35 %) to 0–100 m (surface level) chlorophyll concentrations over large parts of the northern IO, sedimentary sources have similar contribution to chlorophyll concentrations over the southern tropical IO. Such increases in chlorophyll are primarily driven by an increase in diatom population over most of the northern IO. The regions that are susceptible to chlorophyll enhancement following external DFe additions are where low levels of background DFe and high background NO3:DFe values are observed. Analysis of DFe budget over selected biophysical regimes over the northern IO points to vertical mixing as most important for DFe supply, while the importance of advection (horizontal and vertical) varies seasonally. Apart from removal of surface DFe by phytoplankton uptake, subsurface balance between DFe scavenging and regeneration is crucial in replenishing DFe pool to be made available to surface layer by physical processes.