June 2025 | Oceanography
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only nighttime fluorescence data should be used for post-
calibration, while daytime values should be corrected for NPQ
(Carberry et al., 2019). In our case, we show that the NPQ effect
is negligible for our post-calibration. Using discrete data, we
show that the relatively high variance in our calibration is likely
due to the inclusion of both daytime and nighttime data.
Students also engaged with the importance of clarifying what
an instrument measures and what the measurement represents.
The concept of C:Chl ratios is fundamental in biomass assess
ments in oceanographic studies and plays a key role in student
learning outcomes by highlighting how data or model estimates
are influenced by the conversion factors used. We encourage
educators to engage students in discussions on the deep Chl-a
maximum (DCM) in oligotrophic waters and the effects of
photoacclimation on cellular Chl-a content. The DCM has often
been interpreted in scientific literature and textbooks as a bio
mass maximum. However, it primarily reflects photoacclima
tion processes and variations in the C:Chl-a ratio (Mignot et al.,
2014; Cullen, 2015; Maranon et al., 2021). This serves as a crucial
example of why Chl-a should be used with caution as a proxy for
phytoplankton biomass.
Lastly, and this is our central topic, our goal was to empower
students with the formal tools of data science, data manage
ment, and FAIR practices. A career in data science and man
agement can represent a career pathway in itself or a bridge to
other professional opportunities for students. Expertise in data
science is highly transferable and can be applied across a wide
range of professional fields, within sciences and beyond. A nota
ble example is Amanda Herbst, a coauthor of this study, who
after completing a summer internship using the skills covered
here, pursued a Master of Environmental Data Science degree
at the Bren School of Environmental Science and Management
at the University of California, Santa Barbara, and who recently
accepted a position as Environmental Analyst for the New
England Interstate Water Pollution Control Commission
(NEIWPCC) and will be working at the New York State
Department of Environmental Conservation.
Students are exposed to the vast universe of freely available
data and how to handle them. When sourced from data portals
with rigorous quality control procedures and well-documented
metadata, these datasets can be valuable resources for research
and analyses at minimal cost. Many students, researchers, and
institutions face financial constraints when conducting field
studies, which often require expensive platforms (e.g., research
vessels) and instrumentation (e.g., biogeochemical sensors).
By increasing awareness of existing high-quality, open-access
datasets, the oceanographic community could make signifi
cant advancements. In fact, some long-term observational data
sets remain underutilized despite being collected, processed,
and stored following state-of-the-art standards (e.g., NSF Dear
Colleague Letters 2024). Leveraging these resources could
greatly enhance our understanding of oceanographic processes.
CONCLUDING REMARKS
The main goal of this contribution to Oceanography’s Ocean
Education article category is to emphasize to students the
importance of proper handling and sharing of post-calibrated
data by publishing it in open-access data portals. All the data
used in this hands-on activity are openly available, allowing
researchers worldwide to access and utilize them. However,
as demonstrated, interpreting raw Chl-a fluorescence has lim
itations. Therefore, providing the scientific community with
high-quality post-calibrated Chl-a fluorescence data is essential
for advancing research.
An important aspect of sharing high-quality data in open-
access repositories is to include all information necessary for
understanding how the data were acquired and analyzed. This
additional information, known as metadata, includes intel
ligible and descriptive data product names, precise tempo
ral and spatial coverage, accurate and complete lists of science
keywords, and concise yet readable descriptions of the data
products. Instrument calibration documentation (e.g., man
ufacturer calibration) and data analysis workflows are also
crucial metadata components. Publishing open-access data
packages following FAIR principles ensures that the science
is open, transparent, accessible, inclusive, and reproducible
(Wilkinson et al., 2016).
In our case, we created an EDI data package that compiles
post-calibrated underway fluorescence data for six NES-LTER
cruises, spanning from summer 2019 to summer 2021, as part of
coauthor Amanda Herbst’s summer 2021 REU project. The REU
research project included all aspects of the research this exer
cise drew on, including cruise participation to acquire calibra
tion data. The NES-LTER Information Management team sup
ported us in the creation of this data package (Menden-Deuer
et al., 2022). Essential steps in creating a data package include a
clear description of the methods used to process the data, data
quality checks, and additional metadata to improve findability.
These steps benefited greatly from the experience of data man
agers, who play an essential role in modern research projects.
Please note that publishing the data package is not included in
this activity, as all sample data are already published, and multi
ple publications of the same data package are not desirable.
SUPPLEMENTARY MATERIALS
The supplementary materials are available online at https://doi.org/10.5670/
oceanog.2025.314.
REFERENCES
Carberry, L., C. Roesler, and S. Drapeau. 2019. Correcting in situ chlorophyll fluores
cence time-series observations for nonphotochemical quenching and tidal vari
ability reveals nonconservative phytoplankton variability in coastal waters.
Limnology & Oceanography: Methods 17:462–473, https://doi.org/10.1002/
lom3.10325.
Cullen, J.J. 1982. The deep chlorophyll maximum: Comparing verti
cal profiles of chlorophyll a. Canadian Journal of Fisheries and Aquatic
Sciences 39(5):791–803, https://doi.org/10.1139/f82-108.
Cullen, J.J. 2015. Subsurface chlorophyll maximum layers: Enduring enigma or
mystery solved? Annual Review of Marine Science 7:207–239, https://doi.org/
10.1146/annurev-marine-010213-135111.