Thursday, August 27, 2009

The Aral Sea Is Gone

Via NASA's Earth Observatory, an image of the (former) Aral Sea, this August:

Near the dry harbor of Aral, Kazakhstan. Via Wikipedia.
The Aral Sea used to straddle the border between Uzbekistan and Kakakhstan as the world's fourth-largest saltwater lake. A Soviet industrialization program in the 1940s diverted most of its source water to irrigation projects for thirsty cotton farms in the desert. By the 1960s, most of the sea's water supplies had been diverted, and it began to shrink.

As the sea evaporated, a new desert, known locally as the Aralkum, took its place. The desert's soils consist of fine marine deposits mixed with highly polluted runoff from the former industrial cotton farms that used to surround it. Massive dust storms have blown this soil and its pollutants all over the world. The disappearance of the Sea has also removed a tempering influence on the regional climate: winters are now colder, summers are hotter, and there's less rainfall. Ironically, these problems haven't helped the industrial cotton farms that continue to divert water from the former sea's source rivers.

The Aral Sea seen from space in 1985. Via Wikipedia.
At the same time, as the lake shrank, its waters became increasingly saline. The water that remains in the disappearing southern lagoon is now three times saltier than typical ocean water.

The Kazakh government has undertaken a number of projects to restore the northern part of the sea, where water levels have recently stabilized and a fishing industry has even been able to re-establish itself. But the much larger southern portion has been written off as a lost cause, and continues to shrink at rapid rates.

Pretty amazing: in roughly half a century, a sea that was once the size of Missouri has essentially disappeared.

So long, Aral Sea.
We hardly knew ye.

Monday, August 24, 2009

A Field Guide to North American Seafood Menus

The Monterey Bay Aquarium has put together a consumers' guide to sustainable seafoods. The idea is to encourage grocery shoppers and restaurant patrons to support responsible fisheries, like wild Alaskan salmon, and to avoid fisheries that are environmentally harmful or near collapse, like farm-raised Atlantic salmon.

Snapper, Red

Rating: Avoid

Red snapper is in decline worldwide, and fishing pressure on this species remains excessive. Red snapper should therefore be avoided.

Market Names:
Mule Sow, Rat, Tai, American Red Snapper
The guides started as printable pocket versions that you could fold into your wallet and consult at the supermarket. But now there's an even better, more discreet version for mobile phones, accessible at (part of the mobile-phone webpage about Red Snapper, a species that's in serious decline, is shown at right). Or, if you prefer, get the iPhone app. There's even a guide tailored for sushi restaurants that translates common Japanese fish names.

These guides are meant to accompany your menu at the restaurant, but I find them pretty fascinating in their own right. For instance, the Aquarium's guide for the Northeast region endorses Pacific halibut as "best choices," but we're advised to "avoid" Atlantic halibut and flounder caught here in the Gulf of Maine.

Clams (both farmed clams and wild steamers) are also endorsed as a "best choice." Which is good news, as long there's no red tide.

And Monterey is lukewarm about Maine lobster, a fishery that's long been hailed for its socially-driven sustainable management techniques. Maine lobster ranks as merely as a "good alternative," not as one of the "best choices," since the "current population status is considered weak or unknown" and there are concerns about right whales getting trapped in the buoys and lines attached to traps. Haddock also falls into the middling "good alternatives" category, with the caveat that "the majority of U.S. Atlantic haddock is caught using bottom trawl gear [which causes] considerable habitat damage to seafloor habitats."

So maybe I'll switch my preferred clam-shack order from fried haddock with tartar sauce to fried clams, and just opt for salad during red tides or after big rainstorms.

If you're a chef looking for sustainable-fisheries cred, Monterey Bay and a number of other marine research institutions also recently launched, a tool for restaurants and other commercial seafood buyers.

Wednesday, August 19, 2009

Why I Lately Haven't Been Blogging As Much As Usual

In a couple short months, when it's 36 degrees and freezing-raining and you leave work in the dark at 4:30, are you going to be saying to yourself, "I can't believe I didn't go to the beach after work that day while the water in the ocean was twice as warm as it is outside right now."

OR would you rather say to yourself, "Look at this tan I still have, even in November!"

Carpe diem, buddies.

Sunday, August 02, 2009

Beneath the corn, the husks of ancient Venice

This is a farm field near the small village of Altino, Italy, about two miles northeast of the Venice airport, and a mile from the northern edge of the Venetian lagoon:

Look carefully at this aerial view and you can see lines of darker and lighter vegetation slicing across the crop rows. This week's issue of Science magazine features an article by Paolo Mozzi, an Italian geomorphologist who surveyed this same field with infrared cameras during the severe drought of 2007 to analyze subtle variations in plant hydration.

He was looking for crop marks, an archaeological technique that looks at variations in plant health on the surface as a way to discover ancient walls and building foundations that have since been buried beneath three feet of soil. At right is a sketch from Wikipedia that shows how it works: a stone wall just below the surface (on the left side of this sketch) limits the amount of topsoil and stunts the growth of the plants growing above, while an old ditch (on the right) helps the plants above it grow taller with extra topsoil.

Here's what Mozzi's infrared survey found:

This is the ancient Roman city of Altinum, a place that became an important strategic and commercial center thanks to its position at the edge of the Venetian lagoon and at the crossroads of the empire's Via Annia and Via Claudia Augusta. In the fifth century C.E., it and several other Roman cities nearby were conquered and burned by Attilla the Hun, and subsequent barbarian invasions from the north forced the Romans to retreat from the mainland cities to the marshy islands of the lagoon.

Altinum was abandoned completely by the 11th century, but its island refugee settlements grew in size and prosperity to eventually become the city of Venice.

The Roman historian Strabo wrote that "Altinum too is in a marsh... and hence subject to inundations"(see note below). The engineering behind the canals of Venice was pioneered in Altinum, where the Romans built a network of canals to drain the marshes and carry the water away from their buildings. One of the canals is clearly visible in the infrared image above, and, if you know where to look, it's also visible as a slightly darker band of green in the aerial view at the top of this post. When the Romans left, the canals filled in and the marshes took over once again, until the nineteenth century, when the land was reclaimed for farms.

This makes Altinum one of the few Roman cities that wasn't subsequently buried underneath more modern settlements. Instead, it sank into the marshes, only to be re-discovered a thousand years later as a shadow cast over an unwitting farmer's agricultural yield.

Note: Here's the translated source text from "The Geography of Strabo." Strabo calls Altinum similar to the nearby city of Ravenna, which sounds even more like modern Venice: he calls it "a city built entirely of wood [another possible translation is "built on piles"] and coursed by rivers, and it is provided with thoroughfares by means of bridges and ferries. At the tides the city receives no small portion of the sea, so that, since the filth is all washed out by these as well as the rivers, the city is relieved of foul air."