Publications by category
Journal articles
Brewin RJW, Sun X, Aurin DA, Viljoen JJ, Walsh C, Sathyendranath S (2024). Superyachts could support satellite ocean colour validation.
Frontiers in Remote Sensing,
5Abstract:
Superyachts could support satellite ocean colour validation
Visible spectral radiometry of seawater, often referred to as ocean colour, from space, provides a synoptic view of surface phytoplankton, and other optically-active constituents, at high temporal resolution, that is unsurpassed by any other technology. Yet, in-situ observations of ocean colour are critical to the success of the satellite, tracking the calibration of the radiometers and validating atmospheric correction algorithms. Owing to the high cost of commercial field radiometers, as well as the high costs associated with ocean-based field work, ocean colour scientists are plagued by a sparsity of high quality in-situ radiometric observations, particularly in remote regions. In this perspective article, we highlight potential to increase the number of in-situ observations of ocean colour by harnessing superyachts. Using openly-available data processing software, we show that automated ocean colour data collected using a superyacht can be used for the validation of an ocean colour satellite, with comparable results to traditional validation studies. Reaching out to wealthy citizen scientists may help fill gaps in our ability to monitor the colour of the ocean.
Abstract.
Barlow R, Lamont T, Viljoen J, Airs R, Brewin R, Tilstone G, Aiken J, Woodward E, Harris C (2023). Latitudinal variability and adaptation of phytoplankton in the Atlantic Ocean. Journal of Marine Systems, 239, 103844-103844.
Viljoen JJ, Weir I, Fietz S, Cloete R, Loock J, Philibert R, Roychoudhury AN (2019). Links Between the Phytoplankton Community Composition and Trace Metal Distribution in Summer Surface Waters of the Atlantic Southern Ocean.
FRONTIERS IN MARINE SCIENCE,
6 Author URL.
Viljoen JJ, Philibert R, Van Horsten N, Mtshali T, Roychoudhury AN, Thomalla S, Fietz S (2018). Phytoplankton response in growth, photophysiology and community structure to iron and light in the Polar Frontal Zone and Antarctic waters.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS,
141, 118-129.
Author URL.
Conferences
Menzel Barraqueta J-L, Samanta S, Loock J, Cloete R, Viljoen JJ, Mahieu L, Krisch S, Kaukurauee K, Bernhard W, Fietz S, et al (2020). Winter and Spring Trace Metals at the Antarctic Marginal Sea Ice Interfaces. Goldschmidt Abstracts.
Publications by year
2024
Viljoen J, Sun X, Brewin R (2024). Climate variability shifts the vertical structure of phytoplankton in the Sargasso Sea.
Abstract:
Climate variability shifts the vertical structure of phytoplankton in the Sargasso Sea
Abstract
. Marine phytoplankton are essential to ocean biogeochemical cycles. Yet, how climate variability is impacting phytoplankton vertical structure remains unclear. Here, we apply a conceptual model that partitions a profile of phytoplankton into two communities – one in the surface mixed layer and one in the subsurface below – to 33 years of data in the Sargasso Sea. Seasonally, the surface community alters their carbon-to-chlorophyll ratio without changing their carbon biomass, whereas the chlorophyll-a and carbon of the subsurface community covaries with no change in their carbon-to-chlorophyll ratio. At the multidecadal scale, climate variability influences these two communities differently. Over the last decade, subsurface phytoplankton biomass has increased in response to warming. In contrast, the surface phytoplankton has altered their carbon-to-chlorophyll without modifying their carbon biomass. Given that satellites can only view the surface ocean, sustained subsurface monitoring is required to understand fully how phytoplankton are responding to climate change.
Abstract.
Brewin RJW, Sun X, Aurin DA, Viljoen JJ, Walsh C, Sathyendranath S (2024). Superyachts could support satellite ocean colour validation.
Frontiers in Remote Sensing,
5Abstract:
Superyachts could support satellite ocean colour validation
Visible spectral radiometry of seawater, often referred to as ocean colour, from space, provides a synoptic view of surface phytoplankton, and other optically-active constituents, at high temporal resolution, that is unsurpassed by any other technology. Yet, in-situ observations of ocean colour are critical to the success of the satellite, tracking the calibration of the radiometers and validating atmospheric correction algorithms. Owing to the high cost of commercial field radiometers, as well as the high costs associated with ocean-based field work, ocean colour scientists are plagued by a sparsity of high quality in-situ radiometric observations, particularly in remote regions. In this perspective article, we highlight potential to increase the number of in-situ observations of ocean colour by harnessing superyachts. Using openly-available data processing software, we show that automated ocean colour data collected using a superyacht can be used for the validation of an ocean colour satellite, with comparable results to traditional validation studies. Reaching out to wealthy citizen scientists may help fill gaps in our ability to monitor the colour of the ocean.
Abstract.
2023
Barlow R, Lamont T, Viljoen J, Airs R, Brewin R, Tilstone G, Aiken J, Woodward E, Harris C (2023). Latitudinal variability and adaptation of phytoplankton in the Atlantic Ocean. Journal of Marine Systems, 239, 103844-103844.
2020
Menzel Barraqueta J-L, Samanta S, Loock J, Cloete R, Viljoen JJ, Mahieu L, Krisch S, Kaukurauee K, Bernhard W, Fietz S, et al (2020). Winter and Spring Trace Metals at the Antarctic Marginal Sea Ice Interfaces. Goldschmidt Abstracts.
2019
Viljoen JJ, Weir I, Fietz S, Cloete R, Loock J, Philibert R, Roychoudhury AN (2019). Links Between the Phytoplankton Community Composition and Trace Metal Distribution in Summer Surface Waters of the Atlantic Southern Ocean.
FRONTIERS IN MARINE SCIENCE,
6 Author URL.
2018
Viljoen JJ, Philibert R, Van Horsten N, Mtshali T, Roychoudhury AN, Thomalla S, Fietz S (2018). Phytoplankton response in growth, photophysiology and community structure to iron and light in the Polar Frontal Zone and Antarctic waters.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS,
141, 118-129.
Author URL.
