Not all snow falls from the sky – oceanbites

Chawarski, J., Coté, D., Stranne, C., Jakobsson, M., Mayer, L., Cohen, J. H., Geoffroy, M. Distribution of marine snow and copepods range between two Arctic fjords with contrasting ice cowl and stratification regimes. Front. Mar. Sci. 13, 1516750. (2026). https://doi.org/10.3389/fmars.2026.1516750

Snow Below the Surface

Snow in the Arctic may call to mind blizzards and icy landscapes, however the ocean has its own model of snow. It’s referred to as marine snow, and as an alternative of falling from the sky, it rains down by the water. These particles typically appear like smooth, white flakes, which is how they bought their title.

After bursts of organic exercise at the ocean’s floor, tiny bits of natural materials start to sink. This contains useless plants and animals, fecal pellets, microbes, and different particles. As they fall, they feed organisms residing in deeper waters and transfer carbon dioxide from the ambiance to the seafloor. Among the creatures that rely on this falling food are copepods, a sort of zooplankton, or tiny drifting animal, that play a key function in the ocean food web. In flip, copepods are eaten by fish, seabirds, and even whales. In short, marine snow connects floor life to the deep ocean and helps hyperlink microscopic life and bigger animals.

The Ocean Has Layers

The ocean just isn’t one uniform physique of water, fairly it’s more like a layered system. A easy method to image that is a French dressing salad dressing: oil floats on prime whereas vinegar settles beneath. Even should you shake it, the layers separate again. The ocean behaves equally. Ocean water separates into layers based mostly on temperature and saltiness, the place hotter and fewer salty water stays close to the floor and colder and saltier water sinks. This layering known as stratification, and it makes it more durable for the ocean to combine. These layers matter as a result of they control how heat strikes, how vitamins attain marine life, the place organisms can survive, and how particles like marine snow sink.

An Extra Arctic Ocean Twist

Stratification occurs all over the world, however in the Arctic, sea ice provides one other layer of complexity. Sea ice shapes the place and when life can grow, influences how carbon strikes by the ocean, acts as a habitat for a lot of organisms, and impacts how water layers type and blend. Then, when sea ice and stratification work together, they’ll affect how marine snow types, what varieties of particles develop, how fast they sink, the place they travel, and how they clump collectively.

Understanding the Connections

To discover these relationships, the analysis staff studied two fjords during the 2019 Ryder Glacier expedition in Greenland utilizing optics, acoustics, and traditional sampling nets:

Peterman Fjord

Home to the marine terminating Petermann Glacier that drains into Nares Strait, which exports glacial ice
More open water
Less stratified (more mixing)
Greater sea ice export out of fjord

Sherard Osborn Fjord

Home to the marine terminating Ryder Glacier that drains to Lincoln Sea, which accumulates thick multi-year sea ice
Frequently experiences ice damming, the place sea ice acts as a barrier trapping water inside the fjord
More stratified (stronger layering)
Sea ice stays all through a lot of summer time

Their purpose was to find out how stratification and sea ice circumstances would have an effect on major manufacturing, marine snow, and zooplankton communities. The researchers anticipated that stronger stratification in Sherard Osborn Fjord would restrict floor organic exercise and change each marine snow and zooplankton communities.

Figure 1. Study space and sampling websites in NW Greenland. Inset exhibits Northwest Greenland, with the pink box outlining the research area (Petermann and Sherard Osborn Fjords). Colored dots show the places of optical and acoustic sampling utilizing the CTD-rosette, and pink diamonds show the places of multinet sampling websites. All sampling was carried out between August 5 – September tenth, 2019 as half of the Ryder Glacier expedition. Image and caption from Chawarski et al. (2026).

What Did They Find?

With satellite tv for pc imagery, the staff confirmed very completely different sea ice circumstances between the two fjords. Petermann Fjord had misplaced its sea ice by August 14^th whereas Sherard Osborn Fjord remained ice-covered the complete summer time season on account of ice damming (Figure 2). This led to stronger stratification in Sherard Osborn Fjord.

Figure 2. Satellite imagery displaying the seasonal development of ice-break up and formation in the area surrounding Petermann and Sherard Osborn Fjords during cloud-free days. Red-dashed traces point out the fjord boundaries, with areas past the boundary coated by a floating ice tongue. Image and caption from Chawarski et al. (2026).

Life in the Two Different Fjords

The researchers discovered clear, stark variations in the marine snow and zooplankton between the two fjords (Figure 3).

Peterman Fjord (well-mixed)

Greater abundance of all marine snow particle varieties
Primary marine snow sort: darkish combine
More balanced copepod sizes
Higher numbers of copepods, together with juveniles
Copepods unfold deeper in the water

Sherard Osborn Fjord (stratified)

Less marine snow
Primary marine snow sort: flake and darkish combine with small spherical particles in higher layers
Fewer copepod juveniles
More small copepod species
Copepods concentrated nearer to floor

Figure 3. Schematic of the oceanographic circumstances, marine snow and zooplankton abundance and distribution in the prime 100 m of Sherard Osborn Fjord and Petermann Fjord. The pink shade signifies hotter temperatures, and the blue shade signifies colder temperatures. The arrows point out mixing depths. Marine snow and copepod juveniles (nauplii) had been much less plentiful and copepods had been concentrated nearer to the floor in the ice-covered stratified Sherard Osborn Fjord than in the ice-free and combined Petermann Fjord. Image from Chawarski et al. (2026).

The Impact and Future

In open fjords, like Petermann, winds can stir the ocean, bringing vitamins up to the floor and fueling life. But in ice-restricted fjords which can be strongly stratified, like Sherard Osborn, mixing is decreased, vitamins keep trapped beneath, and floor organic exercise declines. This in the end impacts the complete food web, from the microscopic particles to zooplankton and past.

It is unclear which of these two fjord eventualities will turn into more common in the future. Climate change is predicted to increase stratification, which might create eventualities like Sherard Osborn. On the different hand, a discount in sea ice cowl could cut back the probabilities of ice damming, which might produce a Petermann Fjord situation. This signifies that each eventualities on this research may turn into more common elsewhere. To disentangle additional, scientists will need more research connecting physics, ice, and life in the quickly altering Arctic.

Cover image is a copepod (species Calanus finmarchicus), which is a zooplankton generally present in the Arctic. Photograph was taken by Russ Hopcroft and obtained from the NOAA Public Domain Library.

I’m a Ph.D. Candidate at the University of Connecticut–Avery Point finding out the marine carbonate system in the Arctic Ocean. My analysis focuses on biogeochemical modifications occurring within sea ice as the Arctic continues to heat. Outside of my analysis, I take pleasure in climbing, operating, aerial gymnastics, paddleboarding, touring, and spending time with household and buddies.

Article Reference and Inspiration

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