May 27, 2011
I remember an analogy from one of my marine science classes, that studying the ocean is sometimes like trying to study a forest by dropping a bucket from a helicopter. It explains why we know comparatively little about ocean ecosystems, even when they’re situated close to populous areas of land, like the forests of giant kelp (Macrocystis pyrifera) in the Santa Barbara Channel off California. These kelp ecosystems are important because they provide food and habitat for a variety of fish and other species. And now a group of scientists led by the University of California, Santa Barbara found a new way to study the kelp, which enabled them to look at long-term changes in this ecosystem for the first time. (Their results appear in Marine Ecology Progress Series.)
The scientists were able to use images of the area made by the Landsat 5 satellite from 1984 through 2009. (Scientists were not previously able to use the extensive collection of imagery because of the cost; in 2009, Landsat images were made freely available.) “Giant kelp forms a dense floating canopy at the sea surface that’s distinctive when viewed from above,” the researchers wrote. They used the imagery to document the changes in the kelp forests over time and found that, during most years, the forests go through an annual cycle, rapidly growing in spring and summer and dying back during the winter. In some regions, huge waves limit the kelp’s growth, while in others they are held back by a lack of nutrients.
“We know from scuba observations that individual kelp plants are fast-growing and short-lived,” says study co-author Kyle Cavanaugh of UCSB. “The new data show the patterns of variability that are also present within and among years at much larger spatial scales. Entire kelp forests can be wiped out in days, then recover in a matter of months.”
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August 30, 2010
Last week, Bruckner Chase of Santa Cruz set out to become the second person ever to swim across Monterey Bay. He intended to use the publicity surrounding the 14-hour slog to raise awareness about ocean issues.
But then the ocean did a little awareness raising of its own. Thirty minutes into the swim, jellyfish—whose swelling numbers are considered by many to be a symptom of unhealthy seas—began to swarm.
“I’m like, ‘Come on guys, I’m trying to help here,’” Chase said later.
The jellies could not be reasoned with—Chase was soon being stung everywhere, even inside his mouth. He made it through the swim by putting on a wet suit after about two hours, at his wife’s insistence. (She was beside him in an escort boat.) Jellies stopped a California woman attempting the same swim the week before, reportedly stinging her hundreds of times. But even in the wet suit—which protected all but Chase’s face and extremities—conditions were less than pleasant.
“During the last mile,” one news account said, “Chase felt (the jellyfish) oozing through his hands with every stroke and realized ‘that had I not been in a wetsuit, I would not have been able to physically survive.’”
Ah, memories. I spent a chunk of the spring reading stories like this one while researching jellyfish for our 40th anniversary issue, and this summer I haven’t been able to resist keeping up with the latest jelly current events (although I did chicken out of my colleagues’ jellyfish-eating expedition). As usual, the jellies have been up to no good:
- The Mediterranean is jelly soup this summer. Mauve stingers (a creepy glow-in-the-dark variety) shut down several Spanish beaches, and exotic species—like blue buttons and cigar jellies—have been spotted around Malta. A few days ago, a 69-year-old woman was stung by a Portuguese man o’ war (which is technically not a jellyfish) on the Sardinian coast. She went into anaphylactic shock and died.
- Closer to home, black sea nettles have made unwelcome visits to San Diego, another jelly species is plaguing Atlantic City, and at least 10,000 people have been stung near an island off of Georgia (compared to 1,370 in 2006). Lifeguards attribute the stinging streak in part to an unusually robust population of lion’s mane jellies. They’ve been treating the wounds with a product called Jellyfish Squish.
- In New Hampshire, an unwitting lifeguard likely aided the enemy when he tried to remove a dead jellyfish from the beach with a pitchfork. The body broke into floating pieces, stinging more than 100 bathers.
On the bright side, though, scientists have been studying a fish that actually seems to thrive in the jellyfish-infested waters off of Namibia, where most fish species have been pushed out. Cute little bearded gobies are immune to jelly stings and even have a taste for jellies, which make up a third of their diet.
Abigail Tucker is the magazine’s staff writer.
May 21, 2010
The results of Smithsonian‘s 7th Annual Photo Contest were announced earlier this week. The winner in the Natural World category, Hidden frog (above), was taken last September by Laurie McAndish King of Novato, California:
King was experimenting with a new camera in a local Mendocino County garden when a frog paused for a moment on the leaves of a nearby plant. She snapped; it hopped. “I’ve gone halfway around the world looking for new experiences,” she says. “This photo will always remind me of the beauty in my own backyard.”
It’s an important lesson—you don’t need to go very far to find fantastic things—and one that plays out in the photo that won the Grand Prize, Young monks from Myanmar. For the photographer, Kyaw Kyaw Winn, from Yangon, Myanmar, monks are a common sight, but he found something particularly special.
Keep looking around. If you find something interesting and manage to capture it in a photo, consider sending it in. Our 8th Annual Photo Contest runs until December 1.
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May 4, 2010
Bald eagles have made a remarkable comeback. They were nearly wiped out in the mid-twentieth century due to DDT (the chemical causes female birds to lay eggs with thin shells), but following the 1970s ban on the chemical, the birds have recovered so well they were taken off the Endangered Species List in 2007. But that doesn’t mean that they have managed to return to their previous population numbers or to everywhere they once lived. Quite the contrary.
On California’s Channel Islands, researchers have attempted to re-introduce the eagles to the islands since 1980, with varied success. High levels of DDT remain in the marine ecosystem and though chicks have hatched, there have been abnormally high rates of egg failure. And it gets more complicated: a new study, published this week in PNAS, suggests that if the eagles manage to establish themselves in sufficient numbers, the consequences for other threatened and endangered species could be dire.
The favorite food for bald eagles is fish, either marine or fresh, but they are “opportunistic generalists” that will eat a wide range of creatures, either hunting and killing it themselves, scavenging carcasses or stealing from others. In the new study, the biologists analyzed chemical isotopes in bone collagen and feather keratin from a historic nest on San Miguel Island and also material from paleontological sites and other historical sites throughout the Channel Islands to figure out what the birds ate. The scientists determined that seabirds were important prey for the eagles for thousands of years, and after humans introduced sheep to the islands in the 1840s and 1850s, the eagles fed sheep meat to their chicks (I’m assuming they were scavenging sheep carcasses, but I could be wrong).
These findings have important implications for the reintroduction of the eagles to the Channel Islands. The sheep and feral pigs have been removed from the islands, and many seabirds have declined in numbers. The biologists suggest that without these species, the eagles may turn to pinnipeds, which are abundant in the area, or endangered island foxes.
The foxes are the bigger concern. Golden eagles were removed from the islands after they began to prey on the foxes, to prevent their extirpation, but what happens if bald eagles start to kill foxes? Would people support removing bald eagles? And that brings up a larger question: When looking at the natural world as a whole, how do we decide what to save?
March 25, 2010
Marine biologists need your help. The next time you go to the beach, keep a lookout for the creatures that have washed up onto the sand. And if you find a jellyfish, squid or other kind of unusual marine life, including a red tide bloom, please, please report your sighting to Jellywatch.
Jellywatch is the creation of the aptly-named marine biologist Steve Haddock, from the Monterey Bay Aquarium Research Institute. The web site harnesses social networking to create a database of sightings of marine life so scientists can track what is happening in our oceans around the world.
Visitors to Jellywatch can upload information about their sightings, including images, and keep track of what they’ve previously found. They can also compare their sightings with those of other beachcombers from around the world. Already the database has information about a recent red tide off Cornwall, England; pygmy killer whales seen near Hawaii and Humboldt squid near Vancouver Island.
What strange things will you find this summer?
(Hat tip: Helen Fields)