Okhotsk Drift-Ice Seal Floes

Mombetsu & Shiretoko, Hokkaido, Japan · Arctic & Subarctic · polar

About this place

Examine Amur River freshwater stratification driving 44°N sea ice and Phoca largha lanugo pup thermoregulation.

For kids: Visit the southernmost winter sea ice in the northern half of Earth, where fluffy white seal pups ride ice rafts!

Ryuhyo drift-ice floes — Amur halocline seasonal pack ice. Centre the seasonal drift-ice floes advected southward by the East Sakhalin Current
Spotted seal nursery zone — Phoca largha lanugo pupping ice. Locate the pack-ice margin used by spotted seal triads
Steller's sea eagle coastal perch — Haliaeetus pelagicus wintering coast. Scan the coastal headlands used by wintering Steller's sea eagles

Source: Ohshima et al. (2013), Nature Geoscience & Trukhin (2009) — Amur halocline sea-ice conveyor & Phoca largha breeding ecology.

Ask together: Hokkaido is at the same latitude as sunny southern France—why does ocean ice float all the way down here?

Kids' question: Why do spotted seal pups grow up so fast on winter drift ice?

Answer

Mom's super-creamy milk is half rich fat!

Adults' question: Which oceanographic feature enables sea ice to form in the Sea of Okhotsk at 44°N?

Low-salinity surface stratification from Amur River inflow plus Siberian katabatic winds
Submarine permafrost vents freezing the seabed
Antarctic icebergs drifting across the equator
Absence of ocean tides

Answer

Low-salinity surface stratification from Amur River inflow plus Siberian katabatic winds

360° photo: jenspeterhansen, CC BY-SA 4.0

By day: Spotted seals (larga) & ringed seals basking, floating vertically, & diving Tokkari (from Ainu 'tukari' meaning seal) rehabilitates stranded Sea of Okhotsk ice seals; observe nostril valve closure on every dive.
By night: Seals sleeping underwater & surfacing quietly every few minutes to breathe Phocid seals suppress metabolic rate and heart rate during sleep apneas lasting several minutes underwater.

Other language: Русский