Monday, July 31, 2006

"Sentinels Under Attack"

Part 2 on Altered Oceans

Toxic algae that poison the brain have caused strandings and mass die-offs of marine mammals — barometers of the sea's health.

Neuschwander (a California sea lion) was exhibiting the classic symptoms of domoic acid poisoning, a condition that scrambles the brains of marine mammals and causes them to wash ashore in California as predictably as the spring tides.

They pick up the acid by eating anchovies and sardines that have fed on toxic algae. Although the algae have been around for eons, they have bloomed with extraordinary intensity along the Pacific coast for the last eight years.

The blooms are part of a worldwide pattern of oceanic changes that scientists attribute to warming waters, excessive fishing, and a torrent of nutrients unleashed by farming, deforestation and urban development.


More bad news. Seagulls are having problems, also - mostly with starvation.

link: Warmer Waters Disrupt Pacific Food Chain


On these craggy, remote islands west of San Francisco, the largest seabird colony in the contiguous United States throbs with life. Seagulls swarm so thick that visitors must yell to be heard above their cries. Pelicans glide.

But the steep decline of one bird species for the second straight year has rekindled scientists' fears that global warming could be undermining the coastal food supply, threatening not just the Farallones but entire marine ecosystems.

...But not this year. Almost none of the 20,000 pairs of Cassin's auklets nesting in the Farallones will raise a chick that lives more than a few days, a repeat of last year's "unprecedented" breeding failure, according to Russ Bradley, a seabird biologist with the Point Reyes Bird Observatory who monitors the birds on the islands.

Scientists blame changes in West Coast climate patterns for a delay in the seasonal upwelling of cold, nutrient-rich waters from the ocean's depths for the second year in a row. Weak winds and faltering currents have left the Gulf of the Farallones without krill, on which Cassin's auklets and a variety of other seabirds, fish and mammals depend for food.

"The seas are warmer. And the number of krill being produced is lower," said Bradley as he held a Cassin's auklet chick, the only one from a study of 400 nests he expected to survive.

"Normally we would have hundreds," he said.

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