Earth Sciences
Welcome to Stellenbosch University

​​​​​​​​​​Dr. Susanne Fietzdsc_5725.jpg

Senior Lecturer

Department of Earth Sciences,
Stellenbosch University, South Africa
tel +27-21-808-3117
email: sfietz at sun.ac.za

https://susannefietz.wordpress.com/

https://southernoceanfe.wordpress.com/


Research theme: Biogeochemistry in aquatic systems, Environmental Geochemistry, Paleoenvironment, Global Change

Research profile:

My research aims to study modern aquatic systems and sedimentary archives as well as sedimentation processes to help interpretation. This approach provides essential information on past and present environmental conditions for those predicting future local and global changes.

We currently have a major ongoing project on the Southern Ocean: Studying biogeochemical cycles to help evaluate potential tools for climate mitigation. Almost all life on Earth depends somehow on photosynthesis fueled by energy from the sun. Growth, which translates into carbon fixation and thus atmospheric CO2 reduction, however, further depends on the availability of macro- and trace nutrients. One of the most famous quotes of early awareness of climate changes and potential mitigation strategies is from John Martin (Moss Landing Marine Laboratories, US, 1988) "Give me half a ship load of iron...I could give you an ice age". In 2013, there is still no scientific consensus, what the consequences of this type of geo-engineering are. We aim to investigate how phytoplankton, acclimatized to current conditions of light and trace metal availability, will most likely respond to predicted future global warming and thus ocean structure changes. 

Dr ​Fietz seeks students for the following topics

      • Methylmercury in the Southern Ocean. This project is only available to students wishing to pursue at least into M.Sc. A strong interest in interdisciplinary and international work is requested for these projects as it is a collaborative work with Mediterranean Institute of Oceanography, Marseille, France.
      • Southern African dust aerosols: sources, trajectories and impact. This involves analyising their general geochemistry and trace metal composition, and their dissolution kinetics, which leads to study their potential fertilisation and/or inhibitory effects after deposition. A student with an interest in atmospheric sciences is required for this project. The student will work closely with PhD candidate Ismael Kanngueehi. 
      • Algae community composition and adaptation, driving factors and the impact on biogeochemical cycles (including carbon and its impact on the global climate), and/or on marine sediment formation (siliceous ooze, vs. calcareous ooze, for instance). A strong interest in interdisciplinary work, including biological sciences, is requested for this project. 
      • This project includes a component on the toxic and/or inhibitory impacts of selected trace metals on primary producers
      • Another field of studies relates to paleo-geochemistry and climate reconstructions and establishing or improving tools for paleo-reconstructions. We use organic molecules to reconstruct the climate of the past, understand natural variability to disentangle the current anthropogenic impact. This, in turn, helps to improve the projections of the future. 
      • In collaboration with Iziko Museum (Dr Eugene Bergh), a project on Miocene to Recent biostratigraphy and marine palaeoenvironments of South Africa is offered. A part of this is also to investigate if we can record the Plio-Pleistocene marine extinction on our margin. 
      • We also seek support for our study on river pollution and the impact of rainfall events on Western Cape's river water quality. A study conducted in 2016-2018 has revealed interesting trends in the Eerste River and Lourens River and we will extend this study to other rivers of the Western Cape..​


Ongoing or accomplished PhD, MSc and Honours theses at Stellenbosch University:

2021, Liam Quinlan: "Assessing benefits for on-campus phytoplankton pigment analysis"

2021-2022Jayde Bromwhich: "Summer and winter phytoplankton composition in the Atlantic adn Indian sectors of the Southern Ocean"

2021-2022, Emtia Wium: "Impact of potentially toxic trace metals on phytoplankton in waters south of South Africa"​​

2020, Ireland Allisaib: "Natural vs. Anthropogenic dust characteristics and potential impacts"

2019/2020 Sunnette Vos (Uni Pretoria): "Effects of hydrocarbon contamination on virus-host interactions​"

2019, Warrick Daws: "Pollution in Saldanha Bay, Western Cape"​

2019, Herman Boock: "Impact of metal contaminants on marine microorganisms"

2018 + 2019/2020, Raya Stavreva: "Paleo-proxies in sediments of Lake Baikal, Siberia" & "Constraining Barium as paleoproxy"

2016 + 2017/2018 + 2019-2021, Johan Viljoen: “Phytoplankton community composition in the Southern Ocean”

2015 + 2016/2017 + 2018-2020, Ismael Kangueehi: “Composition and impact of Southern African dust”

2018, Sean Househam: "Metal load in water and sediments of False Bay, Western Cape" 

2018, Dylan McLeod: "Nutrient retention in streams of the Western Cape"

2018/2019, Zandria Jordaan: "Driving factors of del13POC in the Atlantic Southern Ocean" 

2018-2020, Asmita Singh: "​​Southern Ocean phytoplankton ecophysiological response to iron availability​" 

2017/2018, Ian Weir: "Testing the Silicate Leakage Hypothesis in the Southern Ocean"

2016 + 2017/2018, Reuben Lazarus: "Urban river pollution in the Western Cape, South Africa"

2017, Jodie Pieterse: "Bacterial and archael community composition in the Atlantic sector of the​ Southern Ocean".

2017, Zahné Pienaar: "changes in deltaC13 across the Southern Ocean and in iron fertilisation experiments"

2017, Patrick Prestele: "Reconstruction of paleo-temperature in Mfabeni peats, SA"

2017, Marcel Labuschagne: "Characterisation of aerosols in the Western Cape, SA"

2017, Gustav Rezelman: "Self-purification potential of Kuilsriver and Stenbras River, Western Cape, SA"

2015, Mari Scott: “Photosynthetic response of Southern Ocean phytoplankton to dust bulk fertilization”

2015, Gillian Trollope: “Establishing a new paleotemperature proxy in the Southern Ocean”

2013-2015, Natasha van Horsten: "Photosynthetic response of Southern Ocean phytoplankton under iron and light limitations"

2013, Ryno Roux: "The applicability of Hydroxy Isoprenoidal -GDGTs as a possible molecular paleoclimate proxy in the Southern Ocean"

List of publications:

  • ​Singh A., Thomalla S., Fietz S., Ryan-Keogh T., Drivers of spatial and temporal variability in Atlantic Southern Ocean phytoplankton photophysiology. (in review, 2021)
  • Fietz S., Baker A., Miller C.S. , Naafs B.D.A., Peterse F., Finch J., Humphries M., Schefuß E, Roychoudhury A.N., Routh J. Terrestrial temperature evolution of southern Africa during the Late Pleistocene and Holocene: evidence from the Mfabeni Peatland (in review, 2021).​
  • Viljoen J.J., Fietz S. Phytoplankton in unique environments in the Atlantic Southern Ocean: fronts, ice and Subantarctic islands (in review, 2021).
  • Kangueehi K., Eckardt F. D., Toesie R., Ravenscroft G. , Fietz S*. Origin, solubility and ocean impact of trace metal aerosols collected over a major iron ore port (in review, 2021).
  • Loock J.C., Cloete R., Mtshali T., Fietz S., Roychoudhury A.N. The biogeochemistry of Cd in the Southern Ocean, Atlantic Sector: lessons learned from a seasonal reoccupation of the ACC (2021, in review).
​2021
  • DATA SET: Fietz, Susanne; Baker, Andrea; Miller, Charlotte S; Naafs, Bernhard David A; Peterse, Francien; Finch, Jemma M; Humphries, Marc; Roychoudhury, Alakendra; Routh, Joyanto; Schefuß, Enno (2021): Late Pleistocene to Holocene GDGT data in Mfabeni peat, South Africa. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.935696
  • DATA SET: Viljoen, Johannes J; Fietz, Susanne (2021): Surface summer phytoplankton pigment concentrations measured by HPLC during the SANAE-56 cruise in the Atlantic Southern Ocean between December 2016 and February 2017. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.932769
  • Cloete R., J.C. Loock, N.R. van Horsten, J-L. Menzel Barraqueta, S. Fietz, T.N. Mtshali, H. Planquette, M.I. García-Ibáñez, A.N. Roychoudhury. Winter dissolved and particulate zinc in the Indian Sector of the Southern Ocean: Distribution and relation to major nutrients (GEOTRACES GIpr07 transect). Marine Chemistry, 2021.​ https://doi.o​rg/10.1016/j.marchem.2021.104031
  • Cloete R, Loock JC, van Horsten N, Fietz S, Mtshali TN,  Planquette H, Roychoudhury AN. Winter biogeochemical cycling of dissolved and particulate cadmium in the Indian sector of the Southern Ocean (GEOTRACES GIpr07 transect). Front. Mar. Sci. 8:656321.​ https://doi.org/10.3389/fmars.2021.656321
  • Kalpana MS, Routh J, Fietz S, Lone MA, and Mangini A (2021) Sources, Distribution and Paleoenvironmental Application of Fatty Acids in Speleothem Deposits From Krem Mawmluh, Northeast India. Front. Earth Sci. 9:687376. https://doi.org/10.3389/feart.2021.687376​​​
  • Farmer J, Hertzberg J, Cardinal D, Fietz S, Hendry K, Jaccard S, Paytan A, Rafter P, Ren H, Somes C, Sutton J., GEOTRACES-PAGES Biological Productivity Working Group Members. Assessment of C, N and Si isotopes as tracers of past ocean nutrient and carbon cycling. Global Biogeochemical Cycles, e2020GB006775 (2021), https://doi.org/10.1029/2020GB006775
    also see the companion paper: Horner et al. Bioactive trace metals and their isotopes  as paleoproductivity proxies: An assessment using GEOTRACES-era data. Global Biogeochemical Cycles, e2020GB006814 (2021). https://doi.org/10.1029/2020GB006814
2020
  • Weir I, Fawcett S, Smith S, Walker D, Bornmann T, Fietz S*. Winter biogenic silica and diatom distributions in the Indian Sector of the Southern Ocean. Deep Sea Research Part I, 103421 (2020). https://doi.org/10.1016/j.dsr.2020.103421
  • Fietz S*, Ho SL, Huguet C, Archaeal membrane lipid-based paleothermometry for applications in polar oceans, Oceanography 33, 104-114, https://doi.org/10.5670/oceanog.2020.207​.
2019
  • Viljoen J, Weir I, Fietz S*, Cloete R, Loock J,​ Philibert R, Roychoudhury AN. Links between phytoplankton community composition and trace metal distribution in the surface waters of the Atlantic Southern Ocean. Frontiers in Marine Science, 6:295, https://doi.org/10.3389/fmars.2019.00295
  • Grand MM, Laes-Huon A, Fietz S, Resing JA, Obata H, Luther GW, Tagliabue A, Achterberg EP, Middag R, Tovar-Sanchez A, Bowie A (2019) Developing autonomous observing systems for micronutrient trace metals. Frontiers in Marine Science 6:35, https://doi.org/10.3389/fmars.2019.00035
  • Cloete R, Loock JC, Mtshali TN, Fietz S, Roychoudhury​ AN. (2019)​ Winter and summer distributions of Copper, Zinc and Nickel along the International GEOTRACES section GIPY05: Insights into deep winter mixing.​ Chemical Geology 511, 342-357https://doi.org/10.1016/j.chemgeo.2018.10.023
2018
  • Viljoen JJ, Philibert R, van Horsten N, Mtshali TN, Roychoudhury A, Thomalla S, Fietz S(2018)​ Response of phytoplankton in growth, community structure and photophysiology to iron and light addition in the Polar Frontal and Antarctic Waters of the Southern Ocean. Deep Sea research I, 141, 118-129  https://www.sciencedirect.com/science/article/pii/S0967063718301420​
  • Huguet C, Routh J, Fietz S, Mahjoor AL, et al. (2018) Temperature and Monsoon Tango in a Tropical Stalagmite: Last Glacial-Interglacial Climate Dynamics​. Scientific Reports, 8, 5386,  doi:10.1038/s41598-018-23606-w​​
2017
​2016
  • Fietz S, Ho S-L, Huguet C, Rosell-Melé A, Martínez-García A (2016​). Appraising GDGT-based seawater temperature indices in the Southern Ocean. Organic Geochemistry, 102C, 93-105. http://dx.doi.org/10.1016/j.orggeochem.2016.10.003.
  • Baker AR, Landing WM , Bucciarelli E, Cheize M, Fietz S, Hayes CT, Kadko D, Morton PL , Rogan N, Sarthou G, Shelley RU , Shi Z, Shiller A, van Hulten MMP (2016). Trace Element and Isotope Deposition across the Air – Sea Interface: Progress and Research Needs. Philosophical Transactions of the Royal Society A.374, 20160190. http://rsta.royalsocietypublishing.org/content/374/2081/20160190​
​up to 2015​