Home / Summaries / Class notes - Climate Change Ecology / species-communities-fossil

Chapters - Past marine ecosystem changes

6 important questions on Chapters - Past marine ecosystem changes

How come that Antarctic communities are currently dominated by invertebrates even at higher trophic levels?

When global cooling set in approximately 3.5millionyears ago, crabs, sharks, and many predatory fish were lost from Antarctic communities.

Where did benthic communities find refuge when temperatures droped?

In past benthic communities, cold-water species have found refuge in deep waters during times of warming, recolonizing shallower waters when temperatures drop.

What is the evidence that marine fauna has responded to "flickers" in the past?

Some species currently found only north of Santa Barbara are found in the same fossil beds with species that are currently found only south of Ensenada. The best explanation for this may be that the warm-water species established farther north during the warm interglacial, which was then interrupted by a millennial-scale cold snap that brought in the more northern, cold-water species. This change was so sudden that the shells became preserved in the same fossil layer.