Living on Earth: Warm Water and Small Sea Creatures (phytoplankton)

Warm Water and Small Sea Creatures

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WILTSHIRE: Yeah, exactly, it's the phytoplankton. Those are the ones that we're looking at very closely here because they're at the bottom of the food chain, it's what basically everyone feeds on. So if something changes at the bottom, you can expect an upward cascading effect. So that's why we look at it everyday.

RYAN: Marine biologists have been monitoring changes in the waters around Helgoland everyday since 1962. And the biggest change they've noticed has been the temperature, which has gone up 1.5 degrees Celsius in the last fifty years. And even more dramatically, the winter temperatures alone have increased by four degrees. As a result, fish like Cod, which like cold water, have moved north. And near Helgoland, researchers have seen an influx of warm water fish like Red Mullets and a diverse array of jellies and little crustaceans. Karen Wiltshire says that warmer water has also had a profound effect on the ocean's microalgae, the phytoplankton.

WILTSHIRE: Well what we see is that the timing of the spring bloom is very much affected by how warm it is in winter. It's just like on land, you end up having the plants starting to grow in early spring and here it's the same in the sea. You've got microalgae, which will start to grow and then things feed on it and then everything starts to get going. And if that timing is changed you have shifts in the whole food chain structure.

RYAN: She says that if it's warm in winter then the algae are prematurely eaten away. That means they don't have time to build up biomass. And then other organisms who rely on them for food suffer. Some researchers say that those changes even have an effect on the largest animals in our world's oceans: the whales.

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