Dr. Imelda Velasquez (PostDoc until 03/2021)

Research Interests:

  • Siderophore and organic binding ligand chemistry
  • Nutrient and trace metal chemistry in coastal and open oceans

Research Project: 

Interactions of trace metals, dissolved organic matter and particles in the Amazon estuary as key processes for metal fluxes into the Atlantic (Amazon Estuary – M147 Cruise)

Amazon Estuary – M147 Cruise project is an official part of the international GEOTRACES Program. The program was established to conduct a global study of the marine biogeochemical cycles of trace elements and their isotopes in the major ocean basins in the world. The M147 cruise corresponds to GEOTRACES cruise GApr11.

The Amazon River is a major source of dissolved organic matter (DOM) and trace elements in the ocean because it has the largest average discharge in the world. Significant amount of particulate matter load from the river partly settles in the estuary thereby affecting complex geochemical reactions and processes in the water column. The global importance of the Amazon riverine input into the ocean prompts an urgent profound investigation of the interactions, dispersion patterns and variability over space and time (high discharge versus low discharge period) of trace metals and DOM in the Amazon estuary and freshwater plume. Hence, the main research topic is to determine detailed distribution and speciation of trace elements along the salinity gradients in the mixing zone of the Amazon estuary and its freshwater plume, in order to quantify their biogeochemical cycling, the riverine contribution to open ocean metal budgets and their interaction with DOM and particulate matter. The scientific goals are (a) to assess the role of the Amazon as a source of trace metals and DOM into the Atlantic and (b) to understand the interactions between trace metals and DOM.

Projects worked on:

2016 – 2020 Amazon-Geotraces (DFG)

RV METEOR (M147) research cruise to the Amazon Estuary, May 2018

Related Publications:

Book Chapter

San Diego-McGlone, M.L., Jacinto, G.S., Padayao, D.O. and Velasquez, I.B. (2008): Eutrophication and its cause/consequences: The case of the Philippines. In Asia-Pacific Coast and Their Management (States of Environment). Series: Coastal Systems and Continental Margins. Vol 11. Mimura, Nobuo (Ed). Springer (ISBN:n978-1-4020-3626-2).

Jacinto, G.S., Velasquez, I.B., San Diego-McGlone, M.L., Villanoy, C.L. and  Siringan, F.P. (2006): Biophysical environment of Manila Bay – then and now, Chapter 18. In The Environment in Asia Pacific Harbours. Wolanski, Eric (Ed.). Springer (ISBN: 1-4020-3654-X).

Jacinto, G.S., Azanza, R.V., Velasquez, I.B., and Siringan, F.P. (2006): Manila Bay: environmental challenges and opportunities, Chapter 19. In The Environment in Asia Pacific Harbours. Wolanski, Eric (Ed.). Springer (ISBN: 1-4020-3654-X).

San Diego-McGlone, M.L. S., Jacinto, G.S., Velasquez, I.B. and Padayao, D.O. (2003): Status of water quality in Philippine coastal and marine waters, p. 96-108. In DA-BFAR (Department of Agriculture-Bureau of Fisheries and Aquatic Resources) Philippine marine capture fisheries profile. Coastal Resource Management Project, Cebu City, Philippines. 378 p.

Journal articles

Velasquez, I.B., Ibisanmi, E., Maas, E.W., Boyd, P.W.,  Nodder, S. and Sander, S.G. (2016): Ferrioxamine siderophores amongst iron binding ligands produced during the remineralization of marine particles. Frontiers in Marine Science 3, 172.

Cabrera, O.C., Villanoy, C.L., Jacinto, G.S., Bernardo, L.B.,  Ferrera, C., Velasquez, I.B. and Azanza, R.V. (2014): Salt-plug estuarine circulation in Malampaya Sound, Palawan, Philippines. Phil. Sci. Lett 7, 428-437.

Velasquez, I.B., Nunn, B. L., Ibisanmi, E., Goodlett, D. R., Hunter, K. A., Sander, S. G. (2011): Detection of hydroxamate siderophores in coastal and Sub-Antarctic waters off the South Eastern Coast of New Zealand. doi:10.1016/j.marchem.2011.04.003.

Poorvin, L., Sander, S. G., Velasquez, I.B., Ibisanmi, E., LeCleir, G. R., Wilhelm, S.W. (2011): A comparison of Fe bioavailability and binding of a catecholate siderophore with virus-mediated lysates from the marine bacterium Vibrio alginolyticus PWH3a.  Journal of Experimental Marine Biology and Ecology 399 (1). 43-47. doi:10.1016/j.jembe.2011.01.016

McMillan, D.G.G., Velasquez, I.B.,  Nunn, B.L., Goodlett, D.R., Hunter, K.A., Lamont, I., Sander, S. G., Cook, G.M. (2010): Acquisition of Iron by Alkaliphilic Bacillus Species. Appl. Environ. Microbiol. 76(20), 6955–6961.

Velasquez, I.B., Jacinto, G.S. and Valera, F.S. (2002): The speciation of dissolved copper, cadmium and zinc in Manila Bay, Philippines. Marine Pollution Bulletin, 45(1-12), 210-217.

Cheevaporn, V., Velasquez, I.B. and Menasveta, P. (2000): Amplification of mercury concentrations in the marine food chain of the East Coast of Thailand. Thammasat Int. J. Sc. Tech. 5(2).