I study the diverse kingdom of marine particles -- the living and the non-living, organic or mineral -- from optical sensors on satellite and in situ platforms. As an optical oceanographer, I aim to reveal their abundance and identity by studying how they scatter and absorb light, and thus change the colour of the ocean. I have harnessed my skills to tackle a wide variety of science questions, ranging from theoretical problems in marine optics to impacts of climate change on phytoplankton.
My research themes and projects revolve around: (1) optical characterization of marine particles, (2) optical remote sensing of marine particles, (3) autonomous observations of marine particles, and (4) applications in marine sciences (see below).
Optical characterization of marine particles
Understanding how marine particles scatter and absorb light is fundamental to optical oceanography and determines the capacity to retrieve quantitative information on the nature and concentration of marine particles from in situ and remote optical sensors. This can be achieved by analyzing conjunct measurements of optical properties and characteristics of marine particle populations in the laboratory or in situ, and/or by optical modeling.
My research contributions to this effort include:
PROJECTS: Belcolour-2, Icescape, Malina, GreenEdge, and WhiteShift. |
Remote sensing of marine particles:
Development and applications in coastal water quality and climate change
Optical satellites detect the solar radiation reflected from the Earth's surface at visible and near infrared wavelengths. Some optical satellites are specifically designed to detect the colour of the ocean, thus named ocean colour satellites. They now provide a twenty-year continuous record of global observations of phytoplankton stocks and water quality. Recent technological advances include increased spatial, temporal, and spectral resolution, enabling to study processes at an increasing level of detail and at increasingly finer spatio-temporal scales.
I studied turbid waters resulting for example from high concentrations of suspended sediments in coastal waters or coccolithophore blooms in the open ocean. These bright waters have the advantage that they can also be studied from optical remote sensors other than ocean colour satellites:
PROJECTS: Belcolour-2, Geocolour, and WhiteShift.
I studied turbid waters resulting for example from high concentrations of suspended sediments in coastal waters or coccolithophore blooms in the open ocean. These bright waters have the advantage that they can also be studied from optical remote sensors other than ocean colour satellites:
- During my PhD, I provided the first space-based observations of tidal dynamics of suspended sediments in the North Sea, a proof-of-concept for ocean colour remote sensing from geostationary satellite platforms. The retrieval of a marine signal from an optical meteorological sensor was remarkable. The European Organisation for the Exploitation of Meteorological Satellites, EUMETSAT, now plans to provide operational water quality products based on my study. My work was considered as a precursor for future geostationary missions with dedicated ocean colour sensors and provided input for an international report, which is studied by all major space agencies with interest in designing future geostationary ocean colour sensors.
- For the WhiteShift project I studied bright waters resulting from intense coccolithophore blooms using the optical meteorological sensor AVHRR which offers global imagery since the early 1980s. This sensor thus offers a unique dataset of long-term observations which allows to investigate the impact of climate change on coccolithophore blooms. By combining remote sensing observations of blooms with remotely sensed or modeled environmental parameters such as sea surface temperature of mixed-layer depth, I showed that phytoplankton blooms of Emiliania huxleyi, a coccolithophore typically associated with temperate waters, are rapidly progressing into the Arctic due to increased inflow and warming of Atlantic waters (see Publications).
PROJECTS: Belcolour-2, Geocolour, and WhiteShift.
Observing marine particles from autonomous ocean profilers
Applications in marine biogeochemistry
Optical measurements can be acquired from increasingly smaller low-power instruments which can be mounted on autonomous in situ platforms such as gliders and profiling floats. These technological developments have led to the birth of Biogeochemical Argo (BGC-Argo) floats, a growing global network of robotic biogeochemical measurements, which typically profile the upper 1000 meters of the ocean at sub-weekly temporal resolution. This has already fuelled new discoveries of environmental control of phytoplankton growth and of the workings of the ocean biological carbon pump. My Marie Sklodowska-Curie project WhiteShift investigated the role of coccolithophore blooms in sinking carbon throughout the twilight zone using BGC-Argo floats.
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My ERC-funded project, CarbOcean (2021-2026), will employ a novel integrative approach to unravel the ocean's biological carbon pump.
The ocean’s biological carbon pump plays a crucial role in storing atmospheric CO2 in the deep ocean, thereby isolating carbon from the atmosphere for decades to centuries. Yet, its capacity to do so is under-constrained and its mechanisms poorly understood.
The CarbOcean team, led by Griet Neukermans, will develop a mechanistic and quantitative understanding of the biological carbon pump using a novel integrative approach that accounts for its two component pumps: (1) the organic carbon pump driven by the photosynthetic production of particulate organic carbon (POC), and (2) the carbonate pump driven by the production of particulate inorganic carbon (PIC). The CarbOcean team will develop a new optical sensor for autonomous quantification of PIC. This technological breakthrough will in turn empower a unique robotic approach to quantify the two key components of the biological carbon pump, which together determine the net transfer of CO2 to the deep ocean and the fate of carbon in the ocean twilight zone. The robotic ocean profilers will be deployed in a wide variety of ocean environments to gather carbon observations and environmental parameters from the well-lit surface ocean through the underlying twilight zone at high spatiotemporal resolution. The observations collected by CarbOcean’s robotic profilers will then fuel hypothesis-driven research on the transformations and fate of carbon in the twilight zone, and facilitate improved representations of the biological carbon pump in biogeochemical models. |
Copyright © 2020. Design by: Griet N.
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