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Daniel Warren Koestner

Postdoctoral Fellow, SEAS Postdoctoral Research Fellow
  • E-maildaniel.koestner@uib.no
  • Visitor Address
    Allégaten 55
    5007 Bergen
  • Postal Address
    Postboks 7803
    5020 Bergen

My current research interests relate to the development and evaluation of optical proxies for characterizing natural assemblages of marine particles. This mainly involves experimental assessment of the inherent optical properties (i.e., absorption and scattering properties) of water samples which have been additionally characterized in terms of particle size distribution and composition. My work has been concentrated in complex coastal environments, including those in the Arctic, and increasingly relates to the use of optical measurement systems on autonomous platforms (e.g., BGC-Argo floats and gliders) to quantify aspects of the biological carbon pump.

Academic article
  • Show author(s) (2024). Measurements of the inherent optical properties of aqueous suspensions of microplastics. Limnology and Oceanography Letters.
  • Show author(s) (2023). Optical Insight Into Riverine Influences on Dissolved and Particulate Organic Carbon in a Coastal Arctic Lagoon System. Journal of Geophysical Research (JGR): Oceans.
  • Show author(s) (2023). On the Potential for Optical Detection of Microplastics in the Ocean. Oceanography. 49-51.
  • Show author(s) (2023). Neural network approach for correction of multiple scattering errors in the LISST-VSF instrument. Optics Express. 32737-32751.
  • Show author(s) (2023). Improved multivariable algorithms for estimating oceanic particulate organic carbon concentration from optical backscattering and chlorophyll-a measurements. Frontiers in Marine Science.
  • Show author(s) (2022). A Multivariable Empirical Algorithm for Estimating Particulate Organic Carbon Concentration in Marine Environments From Optical Backscattering and Chlorophyll-a Measurements. Frontiers in Marine Science.
Academic lecture
  • Show author(s) (2022). Underwater optical communications and contribution from forward scattered light.
  • Show author(s) (2022). UNDERWATER OPTICAL COMMUNICATIONS AND CONTRIBUTION FROM FORWARD SCATTERED LIGHT.

More information in national current research information system (CRIStin)

Improving the capabilities of autonomous platforms in marine science with optical sensors

I have been selected for a postdoctoral fellowship in Optical Ocean Technology as part of the Shaping European Research Leaders for Marine Sustainability (SEAS) program. My research project seeks to advance methodical approaches for the evaluation of particle composition using optical techniques, and to specifically develop and apply approaches for the estimation of particulate organic carbon with autonomous platforms which actively monitor the ocean currently. The work is focused on BGC-Argo floats and gliders which survey the Nordic Seas, in particular the Lofoten Basin. The research project also puts emphasis on guiding the development of the next generation of affordable sensors for use on autonomous platforms using polarized light scattering measurements.

 

Optical properties of aqueous suspensions of microplastics

Currently, quantification of marine microplastics is limited by manual collection and counting resulting in an incomplete assessment of global stocks of marine microplastics. Optical methods can provide a means to circumnavigate these spatial and temporal limitations for global analyses. This research project is focused on the collection of comprehensive measurements of the absorption and scattering properties of microplastic suspensions generated from commonly utilized plastics. These measurements are crucial for the development of optical methods for detection of microplastics and we are working on exploring the potential for satellite or above-water remote sensing of microplastics suspended in seawater.

 

Counting and sizing of marine snow using remotely operated vehicles

Marine snow is the continuous shower of organic material which falls from the upper layers of the ocean. These large sinking particles feed marine life and importantly transfer considerable amounts of carbon from the productive surface layer to the deep ocean. In this project, I am supervising a Master's student to develop real-time systems to count and size marine snow particles using available technology on Remotely Operated Vehicles which explore the Deep Sea. This technology has potential to be used to understand spatial distributions of marine snow which are currently rarely counted and sized, but often observed during typical ROV missions in the Deep Sea.

 

Meditations on the Deep Sea

Public-facing portrayals of the Deep Sea are few and far between; as a result, many people feel disconnected or even fearful of deep-sea environments. On the rare occasions that deep-sea environments are presented, they are invariably saturated with political, environmental, or social narratives laden with strong preconceptions. In this ongoing audio-visual outreach project, we are dedicated to the creation of immersive intimate experiences, connecting us with this unique environment through the narrative power of music.

 

Journey into the Ocean's Colour!

Phytoplankton are the microscopic plants in the ocean producing over half of the oxygen we breathe. At the same time, they play an important role in regulating atmospheric CO2 levels. Just like plants on land, phytoplankton need light to produce energy and transform CO2 into organic carbon situated as the base of marine food webs. The ocean’s colour holds clues to what is living in the ocean and in our research, we study how light interacts with seawater. One of the many amazing tools we use are optical sensors on profiling robots in the ocean called Argo floats. This outreach project focuses on the development of an interactive audio-visual experience using real input of optical information from Argo floats to generate unique sound- and light-scapes to approximate what it is like to sink deep into the ocean as a marine plankton.