Читать книгу Mountains and Marshes - David Rains Wallace - Страница 13
ОглавлениеADJECTIVES FOR A SUPERORGANISM
Crossing San Francisco Bay in an inflatable boat is surprising when you’re used to crossing on bridges. It isn’t simply that you see more of the Bay that way. You have to see more. Otherwise, the Bay will bounce you around. You learn to watch for waves that can fling loose objects skyward; in fact, you learn what it is to be such an object as your shoes say good-bye to the deck and your binoculars wind themselves around your neck. You find that the Bay is more than a stretch of water for building bridges over, that it has palpable rhythms and moods that make it (as far as you in your inflatable boat are concerned) alive.
I discovered these things one May morning as the guest of an excursion company, San Francisco Bay Adventures. We set out from Sausalito and ran up Richardson Bay off Marin County to the Audubon sanctuary there. Michael Herz, a senior research scientist at Tiburon’s Center for Environmental Studies, wanted to look at a harbor seal gathering spot nearby. But new building apparently had scared off the seals, so we turned around and headed toward the Golden Gate. I wasn’t too impressed with the Bay up to that point. Walled with condominiums and houseboats, it seemed inert and opaque.
The Bay corrected my impression south of Sausalito. Within a few yards, air and water changed from smoggy suburban to sparkling marine as we approached the Gate. The boat jounced through a line of waves that had me holding on to my notebook with my toes, then broke into a simmering turbulence like a gigantic whirlpool bath. Terns and pelicans didn’t just fly over, they sailed. Looking eastward, I saw a broad stretch of white water, as though a school of fish or a rocky shoal were breaking the surface. Michael Herz said that the incoming and outgoing tides were meeting there, and he pointed out veins of foam that showed interfaces of salt- and freshwater. During winter floods, he added, river water roaring out of the Gate can move the interface with ocean water as far offshore as the Farallon Islands.
Even during normal outgoing tides, several times more water flows through the Golden Gate than through the Mississippi’s mouth. The Bay’s power and exuberance reminded me of gray whales I’d seen spouting at Half Moon Bay. In a sense, I was watching the Bay spout—breathe—as I watched the tides swirl past, because tides and rivers are what keep the Bay alive just as air keeps whales alive. Yet I still felt confused about the Bay’s functioning. Big as whales are, they are easier to comprehend than a 435-square-mile bay. I didn’t understand the sudden intensity of the change from Richardson Bay to the Golden Gate.
When I stopped at the Army Corps of Engineers’ Bay Model in Sausalito on the way home, I began to understand. With its gray concrete surface and computerized voice ticking off the lunar days, the thirty-year-old model gives little sense of the Bay’s vitality. It does give a very graphic sense of the contrast between most of the Bay’s flat, shallow bottom and the huge underwater canyon that tides and floods have carved through the Golden Gate. Even in the model, where the canyon is three feet deep, its bottom is invisible. I was surprised to realize what an abyss I’d been floating, or rather bouncing, over.
Likening the Golden Gate to a gray whale’s spout may seem farfetched, but many other analogies between the Bay and a living organism are possible. Like a gray whale, the Bay has a life span, an anatomy, and a physiology. It’s just that they are so extended in time and space that we have trouble perceiving them.
THE AGING, RENEWING BAY
San Francisco Bay has existed for at least ten thousand years, since melting ice sheets flooded its basin by raising ocean levels. Because the basin has existed much longer, as sideways movements of the Pacific and North American tectonic plates cracked and tilted California into mountains and valleys, the Bay has had ancestors at various times during the past few million years. A new bay would form when ocean levels were high during interglacial periods, then gradually silt in and revert to land when ocean waters receded.
The rise of California’s mountains did more than form the Bay’s basin. The barrier of the Coast Range forced most of the state’s main rivers to drain into the Pacific through the single outlet of the Golden Gate. Thus the Bay became not only an inland arm of the Pacific but a maritime extension of the Sacramento and San Joaquin river systems—a great estuary where most of the runoff from the Sierra Nevada and southern Cascades meets the ocean. Someday, the rivers will end this Bay’s natural life span by filling it with silt and sand eroded from the mountains. It may already be half full of sediments. They lie three hundred feet deep in places, and average water depth is only twenty feet.
Ocean and rivers shape the Bay’s anatomy. Sea level determines its extent, while rivers deposit marshy flats of silt and sand that divide open water from land. Tidal flows carve sloughs that carry water into brackish and salt marshes, while rivers and creeks cut deltaic channels and backwaters lined with freshwater marshes and riparian woodlands. Tides and streams together cut deep underwater channels that circulate throughout the Bay and converge eventually on the Gate.
Ocean and rivers regulate the Bay’s physiology. Tides that move water in and out of marshes and mudflats twice a day bring food and oxygen to organisms and carry off waste. Rivers transport vast amounts of mineral and organic nutrients into the Bay to be cycled through wetlands, mudflats, and open waters. Storms can increase rivers’ winter and spring flows sixfold. The Bay could no more stay alive without these circulating fluids than a gray whale could live without its blood. Fresh nutrients and water must continually replenish the Bay or it will be starved and poisoned. When upriver water users say that freshwater allowed to run through the Bay to the ocean is wasted, it makes as much biological sense as saying that a whale’s blood is wasted in the whale.
Estuarine wetlands such as the Bay’s are earth’s most productive habitats, fabricating four times as much green plant matter from the raw materials of sunlight, water, and silt as agribusiness cornfields. Warm waters swarming with bacterial action quickly transfer nutrients from silt to photosynthetic cells, and burgeoning algae and marsh plants form primary links in thousands of food chains. Reduced by bacteria to protein-rich detritus, they nourish vast swarms of tiny animals that drift in and out of marshes with the tide, including the young of many larger species—crabs, shrimps, fish, worms, oysters, and clams. The small drifters feed masses of other slightly larger predators that inhabit the Bay or pass through it at some stage in their lives, as with salmon and striped bass. From there, food chains ramify in myriad directions that lead eventually to egrets, cormorants, pelicans, grebes, and diving ducks; to six Bay shark species, one of which may grow to over fifteen feet in length; to hundreds of other fish species; to harbor seals, sea lions, and gray whales.
The Bay is like an enormous turbine, spinning and generating energy as organisms feed, are fed upon, and pass their nutrients along. Far from dissipating this energy, the Bay recycles it with endless ingenuity. A carbon atom carried into the delta by the Sacramento or San Joaquin might make hundreds of passages through the turbine before escaping through the Gate. At first, the atom would ride above the tides flowing in through Carquinez Strait, since freshwater is lighter than salt. It might get pushed up a slough that feeds a delta marsh, enter the roots of a tule sedge, become part of a leaf’s photosynthetic factory, then drift downstream to San Pablo Bay as detritus. There, a bay shrimp might ingest it or the tide might push it up another slough, into a salt marsh, where it would undergo the process of incorporation and decay in a pickleweed. Mixed with the Bay’s saltier waters, it then might sink to the bottom to be consumed by a worm, then by a sand dab. It might stay on the sand through generations of bottom organisms and their predators before tidal flows move it again, and when they do, they might push it back up Suisun Bay instead of pulling it down the final rocky chute of the Golden Gate. Or it might stay in the Bay sediments, an organic speck in the silica matrix of future sandstone.
Understanding the Bay system’s intricacies might require a brain as big as the Bay. But there is a more intuitive way of perceiving its vitality. Like a gray whale, the Bay is beautiful, and while this quality can’t be experienced whole, except perhaps from an orbiting satellite, it can be in hundreds of parts: on a fall afternoon at China Camp State Park, when wooded islands float in a haze above salt marshes and thousands of blackbirds flock on the horizon . . . on a winter evening at San Pablo Bay National Wildlife Refuge, when hundreds of shorebirds rest on mudflats the color of the setting sun . . . on a spring morning at San Francisco Bay National Wildlife Refuge, when orange parasitic plants called dodder growing on pickleweed glow like fire in the green matrix.
The Bay is beautiful—that is, where it is reasonably healthy, which raises another characteristic of living organisms. They can die from injury or disease as well as old age. San Francisco Bay has suffered more than its share of injury in the past two centuries, as silt from Mother Lode mining has smothered its bottom and landfill for urban growth has obliterated more than a third of its original acreage. Indeed, various growth schemes would have filled most of it if the Save the Bay movement hadn’t begun in the 1960s. Jack Foster succeeded in dumping 1.5 million truckloads of rubble into the Bay to make Foster City in 1962. A decade later, David Rockefeller failed to cut off the top of San Bruno Mountain to make a Manhattan-sized Bay island.
Unfortunately, stopping the Bay’s physical obliteration is not enough to save it. Growth has diseased as well as injured it by destroying more than 90 percent of its wetlands, diverting more than 60 percent of its river flows, decimating its biota, and contaminating waters, wetlands, and wildlife with sewage, refinery wastes, pesticide residues, and many other things—an alphabet soup of toxic elements, from arsenic to zinc.
None of the professional Bay-watchers (a research scientist, an environmentalist, a Coast Guard licensed operator, and a boating entrepreneur) who went with me on the inflatable excursion to the Golden Gate doubted for a minute that the Bay was sick and getting sicker. The licensed operator, salty-looking Captain Joshua Mills, saw some improvement in water quality from past decades, when “the water was so black in places you could drop a ham sandwich in it and even a gull wouldn’t touch it.” But he expressed amazement that the Bay had lasted as long as it had, given the pressures on it.
“Improved water quality won’t help the Bay in the long run if all the habitat is lost to development,” said environmentalist John Amodio of the Bay-Delta Preservation Trust.
“Cleaning up sewage and factory discharges won’t even improve water quality if agribusiness keeps diverting more water,” said scientist Michael Herz. “I wouldn’t eat a striped bass out of the Bay now, even if the population wasn’t down 80 percent from the 1960s.”
“I’m afraid the Bay is finished as a commercial fishery,” said recreation entrepreneur Jerry Cadagan, president of San Francisco Bay Adventures. “The San Joaquin River has become a toxic drain. And what’s so frustrating about this is that further water diversion for irrigation isn’t even going to help agribusiness in the long run. It’s just letting them grow crops that are already in surplus while they poison their soil with salt and selenium.”
“The Bay Area is supposed to be environmentally enlightened,” said Amodio, “but there hasn’t been a concerted effort to manage the Bay as an integrated ecosystem. Government bodies have concentrated on their own little fiefdoms, and the conservation community has been trapped responding to political fragmentation. They’re doing better back east in places like Chesapeake Bay. They had a Year of the Bay there. When have we ever had a Year of the Bay? It’s embarrassing.”
“It’s truly awesome just how much has been wrecked,” said Joshua Mills. There wasn’t much to say after that. We finished our sandwiches in the hot sun of a Sausalito deck restaurant and went home.
THE ENDANGERED, ETERNAL BAY
The Bay-watchers’ words had the ring to truth, but, coming from four directions, they caused something of the confusion I’d felt at the Golden Gate. Threats to the Bay are numbingly diverse. I wondered if it might clarify things to consult some kind of human Bay Model, one individual with official authority, scientific knowledge, environmental concern, and practical day-to-day experience on the Bay. It sounded a little like Superman, but I headed to San Francisco Bay National Wildlife Refuge’s new visitor center in Fremont to see what I could find.
I began to think I’d come to the right place when wildlife biologist Tom Harvey listed the things he dealt with on his job. I managed to scribble “water quality, salt ponds, seasonal wetlands, endangered species, diving ducks, colonial nesting birds, the Army Corps of Engineers, the Coast Guard, developers, conservation groups, the Leslie Salt Company, oil spills, wildlife disease epidemics” in my notebook, but others got past me.
“We’re spread kind of thin here,” said Harvey, a thirty-three-year-old with outdoorsy good looks. He’d had the job for five years but has lived near the Bay all his life. “My parents had a house on the estuary at Alameda,” he said, “so the Bay was in the backyard. I remember as a kid being turned on by the richness of life just on a piling or under a rock.”
When I asked him if he thought of the Bay as a living organism, Harvey hesitated, apparently a little surprised by the question. It did sound like deep ecology woo-woo philosophizing in the mundane context of the refuge headquarters’ meeting room, with regulations manuals and memos on the bulletin board, and people in tan uniforms busy at desks next door.
“Yeah, I think I do,” he finally said. “Particularly in the sense of trying to maintain it in a state of health. You have to consider the whole thing to do that.
“I didn’t really start out seeing it that way. My degree is in ornithology, so originally I was just studying birds. When I got this job, there were so many outside influences on the Bay that I had to develop a sense of the whole. We can’t just worry about what’s inside the refuge boundaries or we’ll lose that too, eventually.”
I asked him if he thought the Bay was getting sicker. His response was unhesitating. “Absolutely. I’ve seen it become a less vital place just in my lifetime. The water quality picture is bleak, especially in the South Bay here. There just isn’t enough water coming in to flush out the increasing contaminant levels from all the new development. It isn’t just sewage and factory wastes. A lot of it is grease and oil washing off roads into storm drains.
“We’re still losing habitat that refuge wildlife needs. When it was established in the early 1970s, the planners concentrated on saving the mudflats, salt marshes, and salt ponds because those were considered the sensitive areas, the ones the waterfowl, shorebirds, shellfish, and endangered species needed. Now we’re finding that seasonal marshes inshore from the tidal areas are important too. We used to think the salt marsh harvest mouse [a federally endangered species] was mostly in the tidal marshes, but we’ve discovered that the largest populations are in the seasonal marshes, and the seasonal marshes are going under to development. We’re protecting one part of the Bay and letting another deteriorate. It’s like somebody quitting smoking but taking snuff.”
I knew what Harvey meant by growth pressures. When I’d started going to places like Coyote Hills Regional Park in the early 1970s, much of the South Bay had been in open fields inhabited by ring-necked pheasants and burrowing owls. Driving to my interview with Harvey, I’d passed exactly two open spaces, one with a big Realtor’s sign on it, the other part of the Ardenwood Technology Park, which proclaimed its presence with an outdoor fountain and floral display. The fountain seemed ironic in light of Harvey’s talk of water scarcity, throwing gallons into the air beside a freeway where gridlocked commuters were unlikely to enjoy it.
“The freshwater input from the delta is really critical,” Harvey continued, “particularly down here where the pollution concentrates. If we lose more of that . . . It’s hard not to pessimistic.”
Harvey hesitated again when I asked him if he thought the Bay would survive. It’s the kind of anthropomorphic question that scientists, especially government ones, may not like, but Harvey did his best to answer it.
“There’ll be some kind of bay here. In fact, the Bay will probably grow in the next century because the greenhouse effect is expected to raise ocean levels. It will flood a lot of the present wetlands, so if we don’t save more open space around the Bay now, there may not be any wetlands in the future, just open water next to houses and factories. That will mean even less wildlife. If river inflow keeps decreasing, the Bay will become more of a marine environment—that is, if increased contamination doesn’t cause some truly awesome disaster.
“The threats to the refuge are so diverse that there’s a temptation to get cynical, to say, ‘This place is dying: who cares. I’ll go to Alaska or Oregon.’ But then you go out in the field and see something that reminds you why you keep wading through the paperwork and the meetings. A while ago I was in Richmond looking for California clapper rails [another endangered species]. After three days, I finally found a nest in an area that stank of oil refineries, was covered with landfills and junkyards, and had packs of dogs roaming around. All signs of the high value we’ve placed on wetlands. But then there was this beautiful bird nesting in the middle of this stuff. I was struck by the tenacity. It was sad. But it was a testimonial to something.”
I walked around the visitor center’s nature trail after talking to Harvey. Salt ponds separated the trail from the Bay, and it seemed another irony that we consider them wildlife habitat now, since they replaced natural marshes and were used to produce industrial chemicals. Still, there was wildlife. Black-necked stilts waded daintily in the brine, probing with their slightly upturned bills and complaining raucously as I approached. Swallows skimmed around nests on an old duck-hunting shack. When I stopped to examine some unpleasant-looking blotches in the ponds, I saw that even they were alive, containing thousands of tiny red brine shrimp.
THE WALLED-IN, UNTAMABLE BAY
It was clear from what Tom Harvey had said that the less urbanized North Bay and delta are crucial to the Bay-as-organism, so I headed in that direction one hot, smoggy October day. I’d long wanted to see Suisun Marsh, the largest single estuarine marsh in the continental United States, but somehow never had, despite driving past it many times on I-80. The sprawl around Fairfield hadn’t promised much in the way of open space.
I got a pleasant surprise after negotiating the raw housing tracts and malls around Suisun City. From Peytonia Slough Ecological Reserve at its northern end, Suisun Marsh stretched south toward the Contra Costa hills, with only a solitary barge crane to hint at industrial activity. It was about as close as I’d come to seeing California lowland in a truly wild state, a sweep of tule rushes, cattails, sedges, and wild grasses extending to the horizon. Asters and marsh grindelia added blue, white, and yellow to the marsh plants’ bright green. White-crowned sparrows whistled, marsh wrens chattered, a loggerhead shrike rasped, and an unseen bird, perhaps one of Tom Harvey’s rails, clucked from the tule sedges.
I was even more surprised when a river otter surfaced in the slough. I’d never seen one so close to a town. It stuck its nose in the air and chewed on a small fish like a dog enjoying a succulent bone. When it saw me, it dove and resurfaced behind a clump of rushes, but it wasn’t really alarmed, and I watched it eat two more fish, turning on its back to chew them corncob style. Sweltering in the 90-degree, hydrocarbon-laced air, I envied it.
When I drove southeast to Grizzly Island, I found more open spaces. Early-arriving migratory waterfowl dotted ponds, and the brushy levees and roadsides at the state wildlife area produced many squawking cock pheasants. Two black-shouldered kites, showy white raptors that specialize in marshy, grassy terrain, watched me from a coyote bush, flying away only when I was a few yards from them.
Yet there was a difference between Grizzly Island and the Peytonia Reserve that implied some doubts about the future health of marsh and delta. Although by no means pristine (much of Suisun Marsh was drained and farmed in the 1920s and ’30s), the marsh around Peytonia Reserve is natural, maintained by the interaction of river flows and tidal action that has regulated Bay wetlands for millennia. What I saw of Grizzly Island, on the other hand, is heavily managed for agriculture or to produce game and fish for sport consumption. Rather than allowing wetlands to operate according to a natural water regimen, managers flood or drain the land to optimize crop or game production. The state wildlife area is plowed and bulldozed into squares that might as well be farm fields, except that they aren’t (I hope) laced with pesticides.
There’s nothing wrong with managing duck habitat, especially at a time when waterfowl populations are dwindling alarmingly, but increased emphasis on artificial management showed its ominous side as I talked to people concerned about the future. Under current policies, only diked marshes managed by hunting clubs or the state are assured of dependable freshwater supplies. As more water is diverted from the delta, saltwater creeps into the natural, open marshes. Brackish marshes of rushes and brass buttons turn into salt marshes of pickleweed and cordgrass, habitats less favorable to many wildlife species. Eventually, such places may become so salty as to be almost sterilized.
The state Department of Water Resources proposes various engineering solutions to salt intrusion, such as the massive dam and floodgates it is building near the mouth of Montezuma Slough, Suisun Marsh’s main source of Sacramento River water. The gates are supposed to let freshwater into the marsh and keep saltwater out. But an environmentalist I talked to, Bay Institute founder Bill Davoren, likened such engineering solutions to putting Band-Aids on a failing kidney. Like kidneys, brackish marshes filter pollutants and toxins out of water that ends up in faucets as well as in wildlife habitat. If the 85,500-acre “kidney” of Suisun Marsh should fail, it’s hard to imagine a dialysis that could replace its filtering function in any permanent way.
After leaving Grizzly Island, I went to the Sacramento River at Rio Vista, heading east on Route 12 over miles of parched rangeland that seemed as unlike Suisun Marsh as the Kansas Plains. The river looked like a lot of water by the time I reached it. But appearances can be deceptive. In the drought year of 1931, delta water got so salty that residents couldn’t drink it or irrigate with it. River flow had become so low that saltwater had moved upstream to replace it. Freshwater flow acts as a barrier to saltwater intrusion, the only one that has proven effective.
Driving along the Sacramento’s levee was more comfortable than crossing the Golden Gate in an inflatable boat. Yet, even walled behind levees, the river had a slightly disturbing grandeur that recalled the Gate’s powerful tidal surge. This has to do with the fact that the river’s surface is higher than the fields and orchards bordering it. Peaty delta soils subside when drained for agriculture, while sedimentation raises the levee-contained riverbed’s level above the surrounding land. Engineers say the river is “tamed,” but “caged” might be a better adjective. If it gets out of the levees, it won’t be tame.
River and Golden Gate both had an incalculable look, perhaps because they are the Bay’s main links with the biosphere. The rivers link it to the mountains; the Gate to the ocean. Looking into the Sacramento’s swift flow, I didn’t feel that I understood much of what was going on down there, for all the paper and talk I’d waded through. I didn’t know as much as the big chinook salmon that were cruising off the Gate. They’d know from the river’s taste or smell when the Sacramento was right for them to swim up to spawn, and some would manage it despite everything civilization has put in their way: gill nets, salt intrusion, aqueduct pumping stations, dams, log jams, silted spawning streams. A lot fewer manage it now than even a few years ago, but somehow some still do. My facts and figures seemed thin compared to their knowledge.
Sometimes it seems that our ignorance makes a mockery of even our well-meaning attempts to protect the Bay. Its life can be frustratingly indifferent to our concern, as with Tom Harvey’s clapper rail nesting in a landfill instead of the refuges we’ve made for it. But people keep trying, driven by that “something” Harvey mentioned. It might be a clapper rail or a salmon run or a day’s sailing inside the Gate, but I think it amounts in the end to a recognition that the Bay’s health reflects our own, that we can’t draw a line between living integrity and mere exploitable matter without sooner or later finding ourselves on the wrong side of the line.
—Image magazine, San Francisco Examiner, December 6, 1987
