ORCID Profile
0000-0003-3859-2112
Current Organisation
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
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Publisher: Frontiers Media SA
Date: 09-01-2023
DOI: 10.3389/FMARS.2022.1075155
Abstract: Tropical peat sw s are essential ecosystems, which provide numerous services, and also serve as a rich source of dissolved organic carbon (DOC), hydrogen ions and trace elements to peat draining rivers. However, not much is known about trace element export from tropical peat sw s. We investigated trace element dynamics in rivers and estuaries draining tropical peat sw s on Borneo, and examined the influence of estuarine processes as well as dissolved organic carbon (DOC) on the distribution and concentration of trace elements. Our results indicate acidic conditions (pH = 3.3) and high DOC concentration (3500 µmol L −1 ) at salinities& . We observed an initial release of trace elements at low salinity (0.05& S& 0.5), followed by scavenging to particles at intermediate salinities (0.5& S& ) due to an increasing ionic strength and pH. Peak concentrations (µmol kg −1 ) of Al (24.9), Si (96.2), Mn (4.9), Cu (0.035) and Ni (0.047) were observed during the dry season (July), and Fe concentrations (43.2) were highest during the wet season (December). We used the NICA-Donnan model to investigate the combined impact of DOC and pH on the formation of solid iron hydroxide (Fe(OH) 3 (s)). The Maludam river was predicted to be supersaturated for Fe hydroxides and the results affirmed our model prediction. The output showed Fe and Cu had a strong affinity for DOC and to a lesser extent Al and Ni in the conditions prevailing at the study sites. Statistical analyses also indicated strong correlation between Cu and Ni (r 2 = 0.97, 0.94 and 0.82) in Maludam, Sebuyau and Belait rivers and estuaries, respectively. The results obtained in this study are comparable to values published for southeast Asia and other continents for pristine peat draining rivers.
Publisher: Inter-Research Science Center
Date: 30-05-2013
DOI: 10.3354/MEPS10367
Publisher: Copernicus GmbH
Date: 19-03-2010
Abstract: Abstract. Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas.
Publisher: Wiley
Date: 23-09-2021
DOI: 10.1002/LOL2.10210
Abstract: Lateral fluxes (i.e., outwelling) of dissolved organic (DOC) and inorganic (DIC) carbon and total alkalinity were estimated using radium isotopes at the groundwater, mangrove creek, and continental shelf scales in the Amazon region. Observations of salinity and radium isotopes in the creek indicated tidally driven groundwater exchange as the main source of carbon. Radium‐derived transport rates indicate that mangrove carbon is exported out of the continental shelf on timescales of 22 ± 7 d. Bicarbonate was the main form (82% ± 11%) of total dissolved carbon in all s les, followed by DOC (13% ± 12%) and CO 2 (5% ± 4%). DIC (18.7 ± 15.7 mmol m −2 d −1 ) exceeded DOC (3.0 ± 4.1 mmol m −2 d −1 ) outwelling at all spatial scales. The interpretation of outwelling across the mangrove‐ocean continuum is related to the spatial and temporal scales investigated. At all scales, outwelling represented a major coastal carbon pathway driving bicarbonate storage in the ocean.
Publisher: Frontiers Media SA
Date: 2013
Publisher: American Geophysical Union (AGU)
Date: 23-03-2018
DOI: 10.1002/2017GL076825
Publisher: Frontiers Media SA
Date: 10-04-2018
Location: Brazil
Location: No location found
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Martha Gledhill.