Fig. 1) an open page of the Munsell Soil-Color Chart book

The Munsell Color Chart has been the national standard and official color system for soil research in the U.S. since the 1930s. For nearly 100 years, geologists and soil scientists have taken these color chip pages into the field to better understand the Earth they are studying, so it comes as no surprise that it is the standard for recording ocean cores brought up by the JOIDES Resolution.

Upon first glance, these charts may look like a page of free paint sample strips you can find at your local hardware store, but they are critical to classifying sediment and understanding the environments they came from and can cost several hundred dollars. The Munsell Color System is a method of numerically describing colors. It specifies colors based on hue, value, and chroma and measures them in a three dimensional space. Hue refers to the dominant color of the soil, value is the lightness of the color (scaled 0-10; 0 being black and 10 being white), and chroma is the intensity or saturation of the color.

Fig. 2) A 3D model representation of the Munsell Color System

There are five primary hues, red, yellow, green, blue, and purple, and five intermediate hues, which are a combination of primary hues such as yellow-red (YR) or green-yellow (GY). The hue of a color is represented as a ring and as the rings go up and down a vertical axis, the value of the color changes. As the color moves horizontally from the vertical axis, chroma or saturation becomes stronger or weaker. A color is specified by listing the three numbers or letters for hue, value, and chroma in that order. In the soil color chart, these number letter combinations correspond with a color. For instance, in figure 1, a 7.5YR 5/6 is also called “strong brown” (seen on the left page, bottom right). The names of colors used in weekly expedition reports are not arbitrary or subjective, they are specific and can be easily and accurately charted by anyone with a Munsell Chart reading the report.

Useful or Just Tradition?

The Munsell Color System has limitations. There are a distinct number of samples and the spacing between colors are large, making it difficult to measure thresholds. This inspired new color measuring methods to develop like CIELAB. Read more about CIELAB and what it means here (blog post “Color Science and Ocean Cores”). Changes to the Munsell system were made, doubling the number of hues in Munsell’s original book from 20 to 40, but CIELAB was already on its way to mainstream.

However, it’s still true that Munsell has been the soil color standard for nearly 100 years. That’s 100 years of geological and earth science research using this method of recording color. If scientists were to change to a system like CIELAB, it would mean having to constantly convert units when comparing previous research. Scientists compare and reference previous work all the time. Comparing sediment core colors from different sites can help support their own scientific findings. So switching to a different color recording method would mean converting all previous research. But is that a good enough reason to stick to tradition?

CIELAB creates a standard observer, which is an averaging of color matching that helps set a base value for recordings. This helps create the most accurate color reading on something such as an ocean core. Using color charts opens up the possibility for disagreements as no two human eyes see colors the same. And this really happens! In 2024 while aboard the JOIDES Resolution, EXP401 sedimentologists held long discussions about shades of grey they were recording differently.

Fig. 3) Photos of “The Great Grey Debate” on EXP401 by Dr. Patty Standring

Machines can record accurately and consistently, so why not switch to CIELAB? Well, expensive machines that use CIELAB, like the Section Half Multi-Sensor Logger (SHMSL) take anywhere from seven minutes to hours, recording only one core at a time. When on a two month cruise, pulling up hundreds of meters of core, time is crucial. Cores dry out and potentially change color as they dry, so it’s important to record fresh colors.

The color of a core can tell scientists so much information so quickly.

“Gradual color changes helped us to identify where we saw facies changes on a larger scale. There were very obvious cyclical color changes at Site U1385 that helped establish that the cores preserved a really good orbitally-driven sediment record. Color differences are also really useful when looking at different grain sizes that help identify turbidites and other sedimentary structures, and burrows from bioturbating organisms,” (Standring)

It’s important that scientists record these fresh colors as quickly and efficiently as possible. Although debates about the color grey can happen, these color discussions and international collaborations are what scientific research is all about. After 100 years, Munsell will stay the golden standard, not because it’s what we’ve always done, but because it’s still the best.

Written by Kellan Moss

Thank you to Dr. Patty Standring and Natacha Fabregas for help with this research

Sources:

Berns, R. S. (2016). Color science and the visual arts a guide for conservators, curators, and the curious. Los Angeles Getty Conservation Institute.

EXP 401 Sedimentologists: Dr. Patty Standring ad Natacha Fabregas

Featured Image: MerlinOne Archive

Fig. 1 Image: Here

Fig. 2 Image: Here

Fig. 3 Images: Dr. Patty Standring from EXP401

Color Traditions with Munsell Soil-Color Charts

In early July at Kerteminde, most of the individuals I observed were longer than 10 cm, including one close to 15 cm. Their size, and their timing, deserve immediate attention.

One out of many large speciments I got from Kerteminde (Javidpour, July 2026)

It does not matter whether you call it ribbegople in Danish, Rippenqualle in German or comb jelly in English. The species is the same: Mnemiopsis leidyi. And what I have observed in Kerteminde this summer should concern us. During our current summer field course at the Marine Research Centre, I have repeatedly seen unusually large individuals of M. leidyi around the pier. Most of the animals I observed were longer than 10 cm, even bigger than the one I photographed.

Yes, yes, a pier observation is not a formal population survey….I know. We still need systematic sampling to determine the abundance, distribution and size structure of the population. Nevertheless, the observation is striking because both the size of the animals and the timing of their appearance are unusual, said by someone who is studying this species for the last 20 years.

This is happening earlier than expected

In previous years, the maximum population size of M. leidyi generally occurred several weeks later, mainly during August and early September. Our previous research, including work based on daily sampling, showed a clear seasonal development of the population. The timing varies among years and is influenced by environmental conditions, including winter temperature. Temperature is particularly important because it strongly affects the metabolism of M. leidyi. At warmer temperatures, individuals use their carbon reserves much faster and therefore require more food to maintain themselves and grow. This year, however, the pattern appears to be different. We are seeing very large individuals already in early July. We do not yet know whether this is a local aggregation, an unusually early bloom, transport from another area, particularly favourable feeding conditions or a combination of these factors. But it is a signal that deserves attention.

What does it take to grow by one centimetre?

It is tempting to ask how much energy an individual needs to add one centimetre to its body. The answer is not straightforward because one centimetre of length is not a fixed amount of biomass. Growing from 5 to 6 cm is not the same as growing from 14 to 15 cm…OK? However, we can make a rough carbon-budget calculation using a published relationship between the length and body-carbon content of M. leidyi:

Body carbon in milligrams = 0.0017 × body length in millimetres²·⁰¹³⁸

According to this relationship, an individual measuring 10 cm contains approximately 18.1 mg of carbon. At 11 cm, it contains about 21.9 mg. Adding this single centimetre therefore represents an increase of approximately 3.8 mg of body carbon. If we assume that the animal assimilates approximately 40% of the carbon it consumes, it would need to ingest at least ~10 mg of prey carbon to produce this additional tissue. Using an approximate value of 1 micrograms of carbon for a small copepod, this would correspond to more than 10,000 copepods.

For an already large individual growing from 14 to 15 cm, the estimated increase is approximately 5.3 mg of body carbon. At the same assimilation efficiency, that would require at least 13.3 mg of prey carbon: the equivalent of roughly 15,000 small copepods.

These calculations are only rough, conservative estimates. They are not complete energy budgets. They do not include the food needed for respiration, movement, reproduction, mucus production, excretion or unsuccessful feeding. The real prey requirement would therefore be considerably higher. The important point is that an individual measuring 15 cm represents a substantial transfer of material from the surrounding planktonic food web into gelatinous biomass. One additional centimetre is not “just” one centimetre.

Our students are tracing the food web

The timing of these observations coincides with our summer field course. The students are now collecting M. leidyi, fish, other gelatinous organisms and potential prey for stable-isotope analysis. By comparing carbon and nitrogen isotope values, we hope to obtain a rough picture of the relationships within the local food web. Carbon isotopes can help us trace the original sources of the material entering the food web, while nitrogen isotopes can provide information about relative trophic position.

This will not give us a direct photograph of one organism eating another. Stable-isotope values represent assimilated food over time, and their interpretation depends on appropriate baselines and turnover rates. Nevertheless, combined with information about size, abundance, prey availability and experimental feeding, they can help us understand where M. leidyi is obtaining its biomass and which organisms may be affected. …In simple terms, we are trying to determine who might be eating whom, and where this unusually large population fits into the food web.

Competition with fish is only part of the problem

The concern is not limited to competition for zooplankton. Mnemiopsis leidyi consumes copepods and other small planktonic animals that are also important food for pelagic fish. When the ctenophores are abundant, they can therefore compete directly with fish for prey. Our experiments have also demonstrated that M. leidyi can potentially feed directly on the early life stages of fish. In the study by my previous PhD student, the ctenophores captured and digested Baltic herring yolk-sac larvae. Predation was related to ctenophore size and was not simply eliminated when alternative copepod prey were available. This means that M. leidyi may/can affect fish populations in two ways: by consuming the food needed by fish and by consuming fish eggs or larvae directly.

A recent study by Lucila Sobrero and colleagues in Argentina, within the native range of M. leidyi, found a similar pattern. Their experiments showed size-dependent predation on fish eggs and larvae. Larger ctenophores consumed more eggs. Some eggs were later regurgitated, but many were no longer viable, while fish larvae were retained and digested. These findings are particularly relevant to what we are observing in Kerteminde. The size of an individual is not merely an interesting measurement. It can influence what that individual is capable of capturing and how strongly it affects the surrounding ecosystem. A population consisting of fewer but much larger individuals may still exert substantial pressure on zooplankton, fish eggs and fish larvae.

We need to investigate use, not only control

For several years, I have tried to obtain funding to investigate innovative approaches to this invasive species.

Once M. leidyi is well established, we may not be able to control its regional spread or completely prevent its blooms. But that does not mean that we have no options. We should investigate whether at least part of this recurring biomass can be collected and converted into something useful.

This is not a proposal for a miracle solution. Any utilisation strategy would have to be tested carefully. It must not encourage the further spread of the species, create damaging bycatch or provide an economic incentive to maintain an invasive population. We also need to understand the environmental costs of collection, transport and processing.

But these are exactly the questions that research funding should allow us to answer.

So far, my attempts to secure support for this work have been unsuccessful. Funding agencies do not seem to sense the urgency of studying approaches whose benefits may not be immediate or easily visible. and EPAs do not have any resource to invest in this part. The contrast with events on land is striking. This week, the oak processionary moth, the so-called “larva from hell”, has attracted considerable attention in Odense. Its microscopic hairs can cause rashes and allergic reactions, residents have reported serious discomfort, and a kindergarten has reportedly had to close temporarily. Those concerns are real and deserve a response.

But the case also illustrates how differently we react to environmental threats.

When the impact appears visibly on human skin, the urgency is immediately understood. When ecological damage develops below the surface of the sea, in the form of disappearing zooplankton, altered food webs, consumed fish eggs or reduced larval survival, it is much easier to overlook.

Marine ecosystem changes are often gradual, underwater and largely invisible to the public. By the time their consequences become obvious, the opportunity for early and relatively inexpensive action may already have passed.

Concern does not mean panic

One photograph and a series of observations from one pier do not prove that an ecological crisis is underway. I am not suggesting that they do. But science should not have to wait for undeniable damage before investigation becomes urgent.

The unusually large M. leidyi appearing in Kerteminde this July give us an opportunity to act early. We need systematic monitoring of their abundance and size distribution. We need to measure the available prey field. We need to determine their trophic position and investigate possible consequences for fish recruitment. And we need to explore whether biomass that we may be unable to prevent could be collected and used responsibly.

Whatever language we use and whatever name we give it, the message is the same:

We should measure early, investigate early and support innovative solutions while the warning is still only a warning, not after it has become a crisis.

Relevant publications

Javidpour, J. et al. (2009). “Seasonal changes and population dynamics of the ctenophore Mnemiopsis leidyi after its first year of invasion in the Kiel Fjord, Western Baltic Sea.” Biological Invasions.

Javidpour, J. et al. (2020). “Cannibalism makes invasive comb jelly, Mnemiopsis leidyi, resilient to unfavourable conditions.” Communications Biology.

Stoltenberg, I. et al. (2024). “Predation on Baltic Sea yolk-sac herring larvae (Clupea harengus) by the invasive ctenophore Mnemiopsis leidyi.” Fisheries Research.

Sobrero, L. et al. (2025). “Predatory impact on ichthyoplankton by Mnemiopsis leidyi is size-dependent: an experimental approach.” Marine Ecology Progress Series.

Ribbegople, Rippenqualle or Comb Jelly: Whatever You Call Mnemiopsis leidyi, You Should Be Concerned

Hello from Wales, more precisely, from the Isle of Anglesey in the north of Wales. Here lies the School of Ocean Sciences (SOS) directly at the Menai Strait, where the ocean changes direction by 180 degrees four times a day. My name is Agnes, and I study Environmental Engineering in Munich and have decided to explore a new scientific topic with the GAME project. For someone like me, who is strongly interested in marine biology, it was quite a piece of luck to end up in a place with this high marine biodiversity. Every day, it seems like the sea breathes in and out – but mostly out as it is quite windy here, like a fresh salty breeze going through your hair.

Before arriving here, I never imagined that the nature in North Wales is such a mysterious beauty. It does welcome you to sit in the forests and watch the wind weave its way through the trees, rustling the leaves and casting shifting patches of sunlight across the moss and undergrowth. Sometimes you can hear the calls of birds echoing above, and the scent of damp earth and pine is carried through the air. Or you might walk across rolling green fields speckled with grazing sheep and wildflowers, then reach the rocky coastline where the sound of waves crashing against cliffs rises to meet you. Within minutes, you can watch the deep blue sea stretching below or observe the silver shimmer of sunlight on the water. If you want to experience some lonely time in nature, that’s your place to be. When the deep-hanging clouds allow it, you can even see the mountains with their peaks often veiled in mist, waiting for your visit. There is a certain calmness to the landscape that envelops you, encourages you to be mindful. But let’s take a break from my romantic view of non-cultured nature and give you some information about the life and work here.

Now, I live in Bangor, right next to a natural reservoir, perfect for running or just a slow walk to say goodnight to the sun and the cows who live there. But be careful, it is hilly in Bangor, even though I love to have a walk, the walk up the hill from the city back home takes a while. With the wind and respect to the hilly topography, I sometimes think about what it would be like to be a bird. It seems a perfect place for it.

Many people asked me about the weather before I came here. Wales has a reputation for rain, wind and clouds, but so far, the reality I experienced has been quite different. April and May had been surprisingly sunny and somehow dry. However, locals keep reminding me that summer is still coming. During a hike, one colleague quoted her mother saying, “There is no bad weather, rain just makes the hike more atmospheric.” As a German, I can only agree to this philosophy.

The people at the School of Ocean Sciences are just as welcoming as you can expect from the British. Everyone is willing to help, answer questions, and share ideas. The technical staff, Pete, Aled, and Steve, already provided invaluable support to me while I was planning and building the experimental mesh cylinder. Alice, a marine biologist who volunteers on the project, has also become a great help. Her expertise in identifying marine organisms perfectly complements my background in environmental engineering. My main supervisor, Svenja, and I meet regularly to discuss the progress of my work and solve the inevitable challenges that arise during a field experiment.

Speaking of challenges, I need to mention that, for me, this year’s GAME project is slightly different from the other participants’, as I do not have a team partner. This year’s project examines how underwater soundscapes, such as boat noise, or natural habitat sounds influence the species composition and abundance of sessile marine invertebrates. Each of the two active sound treatment levels plays at a specific temporal rhythm for 2 or 3 months, depending on site-specific restrictions. If there are two team members, then each chooses one of those treatment levels for their experiment. For comparison, there is always an additional treatment level, the ambient control. To ensure the project is feasible while maintaining research quality, I chose to focus on only two sound treatment levels: anthropogenic noise and the ambient background soundscape as the control. Hence, over the next three months, I will use underwater speakers to play back boat noise to simulate exposure to an anthropogenic soundscape at one of my two study sites. At the other site, no additional sound will be added to the existing ambient soundscape.

This experimental design allows me to examine whether differences in underwater sound conditions influence the settlement and growth of marine sessile organisms that attach to hard surfaces such as rocks or, as a substitute, settlement panels. My two experimental sites are located 500 meters apart to ensure acoustic isolation, meaning that the boat-noise playback will not influence colonisation at the Site of the Control Frame (Raft). However, as I am investigating whether boat noise influences community composition, it is essential to ensure that the two experimental sites do not differ substantially in their initial species pool. To assess this, I deployed larval-pool test panels for two weeks before the start of the experiment and identified the species that colonised them. Statistical analyses of these communities, together with information from previous studies conducted at the same locations and accounting for the unique tidal dynamics of the Menai Strait, enabled me to evaluate whether both sites experience comparable environmental conditions and larval supply.

The Menai Strait itself is shaping the local environment and is influencing the practical aspects of my research. Functioning as a channel that separates Anglesey from mainland Wales, it features tidal reversal. During these tidal shifts, water flows in opposing directions at different times, so that as the tide comes in, some water moves toward the strait’s central point. In contrast, simultaneously, other water recedes in the opposite direction as the tide goes out. This situation is comparable to a river that changes direction several times per day in response to the tides. But instead of being one river, the Menai Strait is more like two rivers that meet in the middle of the strait. Furthermore, the Menai Strait experiences some of the largest tidal ranges in the world, with a difference of up to 8 meters between low and high tide. On a personal level, I learned that misjudging the tidal schedule can make it difficult, or even impossible, to retrieve equipment, underscoring how closely the natural dynamics of the Menai Strait are intertwined with the day-to-day realities of conducting fieldwork here.

Alongside the sound experiment, I am deploying additional recruitment panels, which are replaced with empty panels every two weeks. The retrieved panels are transported to the laboratory, where Alice and I identify the newly arrived species. This tracks which colonisers are present in the water column at different times during the experiment, and it is always a surprise which new species are on the panels. One of the most rewarding aspects of the project is the opportunity to see ecological processes unfold over time. Looking at the small, settled organisms through the microscope is like peeking into another world. So far, the panels are full of tiny hydrozoans, barnacles, bryozoans and tunicates.

Being responsible for the experiment in Wales on my own gives me many opportunities to learn and grow as a scientist. I have gained experience in logistics planning, organising fieldwork around tidal cycles, constructing equipment, processing samples, and managing acoustic and biological datasets. I never thought there would be so much planning required for a single site-specific experiment, especially since the theoretical preparation had already been completed during the course in Kiel. Nevertheless, this experience has left me with a long to-do list and many opportunities for further learning. One advantage is the opportunity to work closely with other team members on the GAME project and engage in meaningful exchanges. Whether discussing similar or contrasting challenges, finding solutions, or sharing personal experiences, it is important to both offer advice and share your experience working on an international project, just as much as you receive guidance from others.

At the moment, the experiment is fully underway. The mesh cylinders are in the water, the sound playback is running, and the first settlement panels have been analysed. Over the next few months, I will analyse species, check the sound system, and try to start writing my master’s thesis. Wish me and my little invertebrate’s luck!

I am enjoying life in Wales, learning some new things every day, about British history and environment, and trying to make it up Bangor’s hill. Between the strong tides, the endless shades of green and the ever-changing skies, it is hard not to enjoy the nature of the north of Wales.

To Settle or Not to Settle: Can Boat Noise Tip the Balance?