Helena Frazão

Expertise

My research is characterised by a highly interdisciplinary approach within observational oceanography. My main interests are interactions between physical and biogeochemical processes across multiple temporal and spatial scales, using diverse observational platforms; carbon cycle dynamics in the mixed layer; ocean acidification; and, more recently, optical oceanography. All my research involves extensive sea-going activities.

CV

Since 2025: Postdoctoral research at Leibniz Institute for Baltic Sea Research Warnemünde, Germany
                       Marine Observations Department
                       Project: ISOLUME - IndicatorS Of changing Lightscapes in Underwater Marine Ecosystems

2023 - 2025:  Postdoctoral research at Scripps Institution of Oceanography, University of California, San Diego, USA
                      Climate, Atmospheric Sciences, and Physical Oceanography Department - Ocean Time Series Lab

2022:             Guest Scientist at Scripps Institution of Oceanography, University of California, San Diego, USA

2018 - 2022:  PhD (Dr.rer.nat) at the University of Rostock, carried out at Leibniz Institute for Baltic Sea Research Warnemünde, Germany
                      Marine Chemistry Department - Bio-physical interactions group
                      Title: Spatial and temporal variability in the Northeast Atlantic Subtropical gyre and implications for the biogeochemistry of the region. Supervision: Prof. Dr. Joanna J.  Waniek [link]

2017 - 2018:   Postgraduation in Data Science, Faculty of Sciences, University of Lisbon, Portugal

2016 - 2018:   Researcher scholarship at Marine Environmental Science Centre, Lisbon, Portugal
                      Project: TROANTE

2014 - 2016:   Master's in Marine Science, specialisation in Physical Oceanography at the Faculty of Sciences, University of Lisbon, Portugal
                      Title: Hydrological features of Submarine Groundwater Discharges along the Algarve coast (Portuguese). [link]

2012 - 2014:   Bachelor's in Meteorology, Oceanography and Geophysics at the Faculty of Sciences, University of Lisbon, Portugal
                      Title: Application of an autonomous tool, FUZZYUPWELL, on satellite images from the West coast of Portugal (in the summer of 1996, 1997, 2003-2006)

Publications

2026

• Frazão, H. C, Waniek, J.J. (2026). Century-Scale Variability of Chlorophyll a Concentration in the North Atlantic Subtropical Gyre. Accepted in Environmental Research Communications, doi: 10.1088/2515-7620/ae603f

2025

• Song, R., T. DeVries, R. Li, A. Sutton, U. Send, H. C. Frazão (2025). High-frequency correlations between winds and pCO₂ change the California coastal upwelling system from a CO₂ sink to a source. Geophysical Research Letters 52, e2025GL115470, doi: 10.1029/2025GL115470
• Frazão, H. C., U. Send, A. J. Sutton, M. D. Ohman, T. R. Martz, M. Lankhorst, J. Sevadjian (2025). Open Ocean vs Upwelling Regimes: Air-sea CO₂ Fluxes and pCO₂ Inter-annual Variability in the Southern California Current System. Journal of Geophysical Research: Oceans 130, e2024JC022126. doi: 10.1029/2024JC022126
• Waniek, J. J., H. Osterholz, H. C. Frazão (2025). A Global Inventory of Natural and Synthetic Estrogens in Aquatic Systems. Annual Reviews of Marine Science 17, 511–536. doi: 10.1146/annurev-marine-032123-025855

2024

• Gaye, B., N. Lahajnar, H. C. Frazão, M. Metzke, C. Perkuhn, R. D. Prien, S. Tian, J. J. Waniek (2024). Amino Acids as Indicators of Organic Matter Sources and Degradation in Suspended Matter off the Pearl River: Indications for Resuspension in the Northern South China Sea. Journal of Geophysical Research: Oceans 129, e2024JC021519. doi: 10.1029/2024JC021519

2023

• Dellwig, O., A. Köhler, F. Kurzweil, M. Schönke, A. Wegwerth, S. Krüger, R. Mars, S. Plewe, I. Schuffenhauer, R. Zhang, H. C. Frazão, J. J. Waniek, H. W. Arz (2023). Behaviors of redox-sensitive tungsten and molybdenum in the northern South China Sea: From the Pearl River to the continental slope. Estuarine, Coastal and Shelf Science 292, 108485. doi: 10.1016/j.ecss.2023.108485
• Pachiadaki, M., F. Jansen, M. Carreiro-Silva, T. Morato, G. P. Carreira, H. C. Frazão, P. Heimbach, I. Iglesias, F. E. Muller-Karger, M. Santos, L. M. Smith, M. F. Vardaro, F. Visser, J. J. Waniek, A.-C. Zinkann, A Colaço (2023). Co-designing a multi-disciplinary deep-ocean observing program at the Mid-Atlantic Ridge in the Azores region: A blueprint for synergy in deep ocean research and conservation. ICES Journal of Marine Science 80, 352–254. doi: 10.1093/icesjms/fsac189

2022

• Frazão, H. C., R. D. Prien, D. E. Schulz-Bull, D. Seidov, J. J. Waniek (2022). The Forgotten Azores Current: a long-term perspective. Frontiers in Marine Science 9:842251. doi: 10.3389/fmars.2022.842251

2021

• Kuss, J., H. C. Frazão, Y. Zhong, Y. Gao, J. J. Waniek (2021). The impact of Typhoon “Mangkhut” on Surface Water Nutrient and Chlorophyll Inventories of the South China Sea in September 2018. Journal of Geophysical Research: Biogeosciences 126, e2021JG006546. doi: 10.1029/2021JG006546
• Osterholz, H., C. Burmeister, S. Busch, M. Dierken, H. C. Frazão, R. Hansen, J. Jeschek, A. Kremp, L. Kreuzer, B. Sadkowiak, J. J. Waniek, D. E. Schulz-Bull (2021). Nearshore dissolved and particulate organic matter dynamics in the southwestern Baltic Sea: environmental drivers and time series analysis (2010-2020). Frontiers in Marine Science 8:795028. doi: 10.3389/fmars.2021.795028
• Frazão, H. C., J. J. Waniek (2021). Mediterranean Water properties at the eastern limit of the North Atlantic Subtropical Gyre since 1981. Oceans 2(1), 266-280. doi: 10.3390/oceans2010016
• Frazão, H. C., R. D. Prien, T. J. Müller, D. E. Schulz-Bull, J. J. Waniek (2021). 30 years of temporal variability of temperature and currents below the main thermocline between 1980-2009 in the subtropical Northeast Atlantic (Kiel 276, 33°N, 22°W). Journal of Marine Systems 217, 103517. doi: 10.1016/j.jmarsys.2021.103517
• Deich, C., H. C. Frazão, J.-S. Appelt, W. Li, T. Pohlmann, J. J. Waniek (2021). Occurrence and distribution of estrogenic substances in the northern South China Sea. Science of Total Environment 770, 145239. doi: 10.1016/j.scitotenv.2021.145239