Just northwest of Juneau lies an ecological mother lode.
Berners Bay draws so many wild predators to its banquet of sea life that some scientists say its spring spawning runs are a cornerstone for the region's coastal ecosystems.
But with plans to exploit its other riches - a significant gold deposit - and rim its shores with a highway, the bay's future is murky.
Berners Bay is a year-round nursery for millions, if not billions, of larval and juvenile fish.
In late spring, thousands of predators feast on its spawning runs of hooligan, a type of smelt, and the northern Panhandle's remnant stock of herring.
Scientists believe the bay is important for healthy coho salmon fisheries in upper Lynn Canal, successful breeding by sea lions on the outer coast and the tenuous existence of Lynn Canal's depleted herring stock.
State and federal regulators are hashing out ways to safeguard the bay's marine life and abundant bears, moose and mountain goats as plans are made for the Kensington gold mine, its ferry docks and a proposed road skirting the bay.
But Juneau environmentalists are convinced that these development projects will mute, if not destroy, the bay's annual explosion of life in spring.
"On one hand, I want to say, look at the Lower 48 and what has been lost there. Here we have an intact ecosystem," said John Hudson, a member of the Friends of Berners Bay conservation group.
"It's an ecosystem that includes people," Hudson added. "It's where people in Juneau go to experience the wildness of Alaska."
Operators of the Kensington Mine would investigate and deal with any unintended consequences of its operations in the bay, said Luke Russell, director of environmental affairs for parent company Coeur d'Alene Mines Corp.
"We'll change, learn and adapt as we go through the process. We're confident that the mine can be operated and closed successfully to protect wildlife," Russell said.
To an extent, the ecological and emotional significance of the bay to Juneau residents is heightened by its proximity to town - it's a short boat ride or kayak trip from the Echo Cove dock.
State officials don't deny the proposed projects will alter Berners Bay.
"It's going to change the nature of the bay," said Reuben Yost, an engineer with the Alaska Department of Transportation.
But Yost said that putting a road through it will allow more visitation. "For people who don't have access to it now, it would be a positive change."
There's no denying that the bay has an important role now for the region's wildlife.
To some scientists, the bay is a valuable place to study a few of the most tantalizing questions about Alaska's vibrant marine life and its puzzling declines.
Here, a lucky observer can watch a cooperative feeding tactic by Steller sea lions that hasn't been scientifically documented elsewhere in the world.
Researchers such as Andrew Eller, a University of Alaska Fairbanks graduate student, are trying to deduce the early life patterns of hooligan, which are part of the diverse diet of Southeast Alaska's sea lions.
Not only do hooligan spawn in the bay's rivers, but "they are definitely using the bay as a nursery," Eller says.
The apex of this ecological system is a chain of events that begins in spring, when the water warms up and the estuary turns murky from algal blooms.
In a matter of weeks, the bay lays out a feast enjoyed by eagles, shore and sea birds, sea lions, seals and whales.
The event draws boatloads of bird watchers and a constant procession of kayakers. The Berners Bay Cabin, maintained by the U.S. Forest Service, is booked months in advance.
If a road is built from Juneau to Skagway, cars will zoom approximately 400 feet from the Berners Bay Cabin, which could be made road- and handicapped-accessible.
As soon as they receive final permits, mining firm Coeur Alaska and Native corporation Goldbelt Corp. plan to develop the bay as a ferry corridor for workers at the proposed Kensington gold mine.
The mine will bring in hundreds of jobs and new tax dollars to the city of Juneau, according to the company.
The mine's proposed ferry traffic and docks would pose some new risks for marine life, such as spawning herring and foraging sea lions and whales, aid Carl Schrader, a habitat biologist for the Alaska Department of Natural Resources.
If the state proceeds with its controversial Juneau Access road, the bay will be bridged and rimmed by part of the 68.5-mile project connecting the capital to the continental highway grid at Skagway.
The highway would bring greater access to Juneau. It will also increase public pressure on the bay's dense but finite resources of salmon, steelhead, bears and moose, biologists say.
State regulators are considering a project to put radio collar on bears in Berners Bay to track their movements in relation to the road route.
"It will help (us) learn if there are areas where we want to keep people out or protect habitat," Yost said.
The effort to safeguard the bay's unique ecology is taking regulators into uncharted territory, Schrader said.
The fact that it is an estuary, a nutrient-rich intertidal zone where salt and fresh water mix, "is one of the reasons that it Berners Bay is so important biologically," Schrader said.
But there isn't a lot of science to show regulators how much disturbance the bay's marine or terrestrial species can tolerate, he said.
"If there's any uncertainty, it's over the degree (of harm)," responded Bruce Baker, a former state biologist and board chairman of the Southeast Alaska Conservation Council.
One of the biggest threats is fuel or oil spills in the bay, which could damage rearing and spawning areas for herring and other fish species.
"That's why, on this project, we're really paying a lot of attention to oil spills" and fueling, said Schrader, of the Department of Natural Resources.
But the conservation council accuses state and federal regulators of running a piecemeal review of the projects in the bay, ignoring their cumulative harm.
The National Marine Fisheries Service has opined that the mine's marine traffic in the bay will likely disrupt sea lions, perhaps causing them to leave the area, but the disruption would not endanger the entire eastern Alaska population of sea lions.
"It raises the question, how many individuals do you have to impact before you put the population at jeopardy?" Baker said.
It was only over the last few decades that local scientists such as Mary Willson began to document the bay's complex web of life.
Between 1996 and 1998, Willson led a survey team that counted animals in the bay. Hundreds of sea lions and bald eagles. Tens of thousands of gulls. Small pods of whales.
The animals, most of them, came there for the hooligan - a seasonal prey for sea lions, seals and other animals.
It's hard to predict how the development will affect the overall ecology of Berners Bay, said Stanley "Jeep" Rice, habitat program manager for the National Marine Fisheries Service's Auke Bay Lab.
In 2004, the lab began a long-term project to monitor the bay's ecological health - before and after mineral extraction, ferry docks and the new road.
"It's a very clean environment right now. We want to watch how it changes over 20 to 30 years," Rice said.
With so many types of wildlife using the bay, it isn't an easy job to predict the fallout from an accident or disruptions.
"What's the weak link in any life history change?" Rice said.
"Up here in Alaska, a lot of the time, survival means how you get through the winter. You have to yolk up eggs and avoid predators. In the spring, you have to reproduce," he said.
Now that his federal lab is committed to monitoring the bay, Rice said he hopes future generations will have "a better read" on the consequences of its development.
"We're looking at it more holistically now," Rice said.