Ice Ages and the Genetic Legacy of the Oceans

Sea change
Published in
2 min readNov 26, 2019


Photo by Jonatan Pie on Unsplash

How Ice Ages and Climate Change Shaped the Seas

Did you know our oceans haven’t always looked the same? Turns out, the coming and going of massive ice ages — especially the Last Glacial Maximum — have dramatically shifted where sea creatures live.

The Last Glacial Maximum was a harsh time. Giant ice sheets pushed many cold-loving species far south. Think of it like a massive game of ocean-wide musical chairs. As the climate warmed, some populations that survived found their way back north, but things had permanently changed.

Genetic Footprints of the Past

These changes left marks in the very DNA of marine species. Areas where critters held out during those icy times show a lot of genetic diversity — it’s like a super-rich gene pool of possibilities. Areas newly colonized, well, they tend to be a bit less diverse.

A Study on Seaweed Tells a Story

In a recent study, researcher dug into the story of Fucus vesiculosus, a type of brown seaweed. They used fancy computer models to map where this seaweed likely lived in the past vs. where we find it today. The results were super cool! It turns out, today’s areas with the most seaweed genetic diversity were spots it likely hung tough during colder times. That matches an idea called niche conservatism — basically, that species like the conditions they’ve always known. The study also showed that areas gained by seaweed as ice retreated hold distinct genetic profiles.

Fucus vesiculosus, a brown large algae capable of structuring importante marine forests.

The unfortunate part? This research suggests that as our climate warms again, we might lose unique seaweed populations along the southern edge of their range. That means losing precious genetic diversity.

Why This Matters

Stories like this show us that climate change isn’t just about temperatures. The way it reshuffles entire ecosystems leaves a lasting mark on the very building blocks of ocean life.

Let me know if you’d like any part of this made more conversational or if you want more focus on specific points!



Sea change

Hi!! I’m Jorge Assis, a Data Scientist, Marine Ecologist, Climate Change Analyst, R and Python Developer based in Portugal []