Manganese in the eastern Atlantic Ocean: processes influencing deep and surface water distributions

Statham, Peter J.; Yeats, P. A.; Landing, William M.

doi:10.1016/s0304-4203(98)00007-3

Cited by 71 publications

(40 citation statements)

References 36 publications

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“…The concentrations of DFe in deep waters are typical for the North Atlantic (Wu et al, 2001). The concentrations of DMn were also in the range reported in the literature for surface and deep waters of the Atlantic Ocean (Statham and Burton, 1986;Statham et al, 1998;Landing et al, 1995). Therefore, at station 44, no clear impact of the continental slope or shelf was observed for DFe and DMn.…”

Section: Distributions Of Dfe and Dmnsupporting

confidence: 74%

Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay

Laës-Huon¹,

Blain

Laan

et al. 2007

Biogeosciences

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Abstract. Dissolved iron (DFe; <0.2 µm) and dissolved manganese (DMn; <0.2 µm) concentrations were determined in the water column of the Bay of Biscay (eastern North Atlantic Ocean) in March 2002. The samples were collected along a transect traversing from the European continental shelf over the continental slope. The highest DFe and DMn concentrations (2.39 nM and 6.10 nM, respectively) were observed in the bottom waters on the shelf at stations closest to the coast. The release of trace metal from resuspended particles and the diffusion from pore waters were probably at the origin of elevated DFe and DMn concentrations in the Bottom Boundary Layer (BBL). In the slope region, the highest total dissolvable iron (TDFe), DFe and DMn values (24.6 nM, 1.58 nM and 2.12 nM, respectively) were observed close to the bottom at depth of ca. 600-700 m. Internal wave activity and slope circulation are thought to be at the origin of this phenomenon. These processes were also very likely the cause of elevated concentrations (DFe: 1.27 nM, DMn: 2.34 nM) measured in surface waters of stations located in the same area. At stations off the continental slope, the vertical distribution of both metals were typical of open ocean conditions, indicating that inputs from the continental margin did not impact the metal distributions in the offshore waters.

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Section: Distributions Of Dfe and Dmnsupporting

confidence: 74%

Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay

Laës-Huon¹,

Blain

Laan

et al. 2007

Biogeosciences

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“…While this surface maximum is typical of manganese profiles from tropical and subtropical regions, its uniformity across the region is perhaps surprising. Aeolian deposition is often invoked as a primary source of manganese to the surface ocean (Statham et al 1998). Given the low dust deposition predicted for this region (Fig.…”

Section: Discussionmentioning

confidence: 99%

Basin‐scale inputs of cobalt, iron, and manganese from the Benguela‐Angola front to the South Atlantic Ocean

Noble

Lamborg

Ohnemus

et al. 2012

Limnology & Oceanography

144

193

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We present full-depth zonal sections of total dissolved cobalt, iron, manganese, and labile cobalt from the South Atlantic Ocean. A basin-scale plume from the African coast appeared to be a major source of dissolved metals to this region, with high cobalt concentrations in the oxygen minimum zone of the Angola Dome and extending 2500 km into the subtropical gyre. Metal concentrations were elevated along the coastal shelf, likely due to reductive dissolution and resuspension of particulate matter. Linear relationships between cobalt, N 2 O, and O 2 , as well as low surface aluminum supported a coastal rather than atmospheric cobalt source. Lateral advection coupled with upwelling, biological uptake, and remineralization delivered these metals to the basin, as evident in two zonal transects with distinct physical processes that exhibited different metal distributions. Scavenging rates within the coastal plume differed for the three metals; iron was removed fastest, manganese removal was 2.5 times slower, and cobalt scavenging could not be discerned from water mass mixing. Because scavenging, biological utilization, and export constantly deplete the oceanic inventories of these three hybrid-type metals, point sources of the scale observed here likely serve as vital drivers of their oceanic cycles. Manganese concentrations were elevated in surface waters across the basin, likely due to coupled redox processes acting to concentrate the dissolved species there. These observations of basin-scale hybrid metal plumes combined with the recent projections of expanding oxygen minimum zones suggest a potential mechanism for effects on ocean primary production and nitrogen fixation via increases in trace metal source inputs.

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“…In particular, Gallego-Torres et al (2014) suggest that site GeoB7926-2 was under the influence of Antarctic Bottom Water (AABW) during the LGM. AABW contains lower Mn concentrations relative to North Atlantic water masses (Statham et al, 1998;Idrus, 2013). Mn is scavenged from AABW as it flows north, and thus when reaching site GeoB7926-2 is Mn-impoverished.…”

Section: Late Mis3-late Lgm (35-19 Ka)mentioning

confidence: 99%

A comparison of benthic foraminiferal Mn / Ca and sedimentary Mn / Al as proxies of relative bottom-water oxygenation in the low-latitude NE Atlantic upwelling system

et al. 2015

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Abstract. Trace element incorporation into foraminiferal shells (tests) is governed by physical and chemical conditions of the surrounding marine environment, and therefore foraminiferal geochemistry provides a means of palaeooceanographic reconstructions. With the availability of high-spatial-resolution instrumentation with high precision, foraminiferal geochemistry has become a major research topic over recent years. However, reconstructions of past bottom-water oxygenation using foraminiferal tests remain in their infancy. In this study we explore the potential of using Mn / Ca determined by secondary ion mass spectrometry (SIMS) as well as by flow-through inductively coupled plasma optical emission spectroscopy (FT-ICP-OES) in the benthic foraminiferal species Eubuliminella exilis as a proxy for recording changes in bottom-water oxygen conditions in the low-latitude NE Atlantic upwelling system. Furthermore, we compare the SIMS and FT-ICP-OES results with published Mn sediment bulk measurements from the same sediment core. This is the first time that benthic foraminiferal Mn / Ca is directly compared with Mn bulk measurements, which largely agree on the former oxygen conditions. Samples were selected to include different productivity regimes related to Marine Isotope Stage 3 (35-28 ka), the Last Glacial Maximum (28-19 ka), Heinrich Event 1 (18-15.5 ka), Bølling Allerød (15.5-13.5 ka) and the Younger Dryas (13.5-11.5 ka). Foraminiferal Mn / Ca determined by SIMS and FT-ICP-OES is comparable. Mn / Ca was higher during periods with high primary productivity, such as during the Younger Dryas, which indicates lowoxygen conditions. This is further supported by the benthic foraminiferal faunal composition. Our results highlight the proxy potential of Mn / Ca in benthic foraminifera from upwelling systems for reconstructing past variations in oxygen conditions of the sea floor environment as well as the need to use it in combination with other proxy records such as faunal assemblage data.

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Manganese in the eastern Atlantic Ocean: processes influencing deep and surface water distributions

Cited by 71 publications

References 36 publications

Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay

Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay

Basin‐scale inputs of cobalt, iron, and manganese from the Benguela‐Angola front to the South Atlantic Ocean

A comparison of benthic foraminiferal Mn / Ca and sedimentary Mn / Al as proxies of relative bottom-water oxygenation in the low-latitude NE Atlantic upwelling system

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