The Golden Gate transmits a vast volume of water back and forth from the Bay twice each day, regular as clockwork but in a much more complex rhythm. Photo by Andrew Alden.

These days, most people in the San Francisco Bay Area arrange their daily lives around the clock. But in former times it was the sun, moon and tides that governed the rhythm of our days. Nowadays the sun and moon attract notice only on the rare occasions when they have eclipses. But the tides still matter.

The twice-daily ebb and flow of the tides is not just a factor for ships navigating the San Francisco Bay shallows, although that is important. The tides are how the Bay breathes. The Bay's windpipe is the Golden Gate, a deep channel that enables seawater to spread nutrients and oxygenation to its lungs—wetlands as far away as the Central Valley. In turn, sediment from nearly half of California's surface area is exhaled to the Pacific where it piles up in a great furrowed berm just off the Golden Gate.

Tides arise from the interactions of the sun and moon with our planet; they are where the heavens most truly move the Earth. While mariners always had a good sense of the patterns of the tides, it took science to make them predictable. When Isaac Newton first grasped that the motions of heaven and Earth fit the same mathematical laws, in the mid-1600s, he saw that one very practical application would be in precisely describing—in modern terms, modeling—the tides.

Newton's tantalizing task is considered fairly well solved today, but it has taken centuries to arrive at this point. (Wikipedia has a good introduction.) Today Bay Area tides are monitored and forecasted by the National Oceanographic and Atmospheric Administration; NOAA's Tides and Currents website will serve you official tide data for many stations (like San Francisco's station at Crissy Field).

But even the most exacting mathematics gives us only a partial picture. Weather and climate both matter, too. As weather fronts and storms and winds impinge on the Bay's water, they can change the tides by as much as two feet. Semi-annual climatic cycles like El Niños add their slower influence. And sea-level rise adds its inexorable direction over the scale of a lifetime. For the best view of the day's exact coastal conditions, I look to surfers and the surf-forecast.com site. The tide is important for beach geologizers, too.

The other big influence on the tides in any given place is bathymetry—underwater topography. Mathematical modelers can treat the different parts of the Bay as giant bathtubs, each sloshing back and forth in its own rhythm and spilling into its neighbors, but that analytical approach has limits. For serious analysis of things like stormwater surges, major shoreline construction and channel dredging, the old-fashioned scale model—the Army Corps of Engineers' Bay Model in Sausalito—still matters.

Bay Model in Sausalito photo by hairygrumpy of Flickr under Creative Commons license

It's a painstakingly calibrated replica, one-thousandth true size or about one and a half acres, whose pumps and sumps produce realistic versions of the Bay's complicated breathing. (Unfortunately it's being renovated as I write this, but the Visitor Center is still open to help you learn about the Bay in other ways.)

 Watching the Tides Educator Guide

Ocean tides rise and fall twice a day, influenced by the gravitational forces of the sun and moon. Studying tides' rhythmic movements helps us understand both the ocean and the cosmos. Astronomer Ben Burress explains how tides work, and QUEST visits Crissy Field in San Francisco to see the oldest continually operating tidal gauge in the Western Hemisphere.

Sittin' on the dock of the bay, watchin' the tides roll away.

This is important because the bay and ocean currents flooding in and out of the Golden Gate are notoriously treacherous.  The US Government realized early on the importance of San Francisco Bay and the need to better understand the movements of the water for navigation.  Soon after California became a State, American surveyors were sent to San Francisco to study the water conditions of the great port.  And the work has continued non-stop ever since.  For over 150 years the San Francisco Tide Station, now operated by NOAA, has produced a continuous recording of water levels and other vital maritime information.

Today the tide station uses state of the art equipment to measure the water movement of San Francisco Bay. The water gauges are connected to the NOAA Physical Oceanographic Real-Time System (PORTS), and measure nearly real-time water levels, surface and sub-surface currents and other information such as winds, weather and climate data.  This information is available to the public so sailors know the best times to cast off, make transits, load or unload cargo, or when to ride the tides in or out of the bay.  According to a report written by Captain Albert E. Theberge, NOAA (Ret.), “This information is critically important considering that there is an average of 261 deep-draft vessels entering San Francisco Bay each month and there are approximately 85,000 registered pleasure boats using approximately 100 yacht clubs in the Bay system.”

“The historical record from the tide station at San Francisco transcends the maritime history of the San Francisco Bay,” according to Captain Theberge.  “From the days when clipper ships relied upon tide predictions provided by the station to navigate the dynamic waters of the Golden Gate, to the modern day mariner that obtains real-time water levels so that the huge ship and crane barge operators can tell if they have enough depth in the channels and enough clearance under the bridges.”

In the process of collecting data to insure safe passage in and out of the bay, the San Francisco Tide Station has been instrumental in collecting a long and continuous stream of scientific data that has advanced our knowledge of the oceans and the earth. This data has benefited meteorologists, oceanographers and climatologists alike.  As we look to the future and attempt to better understand the changing climate and what that will mean to things such as sea level rise, the current and long-term data collected at this small station will become increasingly more important.  “San Francisco is an amazing city in terms of its heritage,” says Mary Jane Schramm, “ The human heritage as well as the magic and mystique of the great Golden Gate.  It’s a portal for exploration.  We are explorers and by virtue of having this facility here helps foster that process along.”

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Producer Chris Bauer filming over the Gulf of the Farallones National Marine Sanctuary in NOAA's Twin Sea Otter plane.

Much of the ocean waters off the coast of California, from Bodega Head to Cambria, have been set aside as national marine sanctuaries. The primary objective of the sanctuaries is to protect our delicate ocean resources while allowing people to use the areas in a sustainable way. While most recreation, commercial fishing, and shipping are still allowed within sanctuary waters, some activities are now strictly regulated or prohibited.

But how do you manage such an enormous area? And how do you keep tabs on what is going on out there? QUEST producers Lauren Sommer, Jenny Oh and I hitched a ride to find out.

On the windswept tarmac of the Sonoma County Airport, a team from the National Oceanic and Atmospheric Administration takes to the skies to patrol large portions of the Cordell Bank, Gulf of the Farallones and Monterey Bay National Marine Sanctuaries.

The mission of our Twin Otter flight crew, pilots Bradley Fritzler and Jason Mansour from NOAA Corps, along with sanctuary observers Sage Tezak and Michael Carver, is to conduct abundance surveys of users in the sanctuaries, counting boats and recording what they are doing and where.

We start out crossing Bodega Bay, flying multiple transects, back and forth, across the rolling seas of Cordell Bank. The engine noise is deafening in the unpressurized cabin. We scan the whitecaps from a mere 1000 feet, going only about 90 knots. The rugged aircraft bucks in the turbulent wind coming off the water. Flying this low and slow would give some pilots the jitters but for the Twin Otter flight crew it’s just a walk in the park. As we reach the Farallon Islands, I pop the back window to get a better camera angle of the “Devil’s Teeth,” and in the process pray our camera doesn’t get sucked out into the abyss. From the Farallones we bank south and head to Ana Nuevo Island. From there we’ll circle back up the coast, past Half Moon Bay and San Francisco, over Pt Reyes National Seashore and return to Sonoma County. Total flight time: 3 hours. In addition to surveying boat use in the sanctuaries, the observers and flight crew will document any other sightings, such as whales and keep a look out for maritime violations.

California has recently established new marine protected areas along the coast. These MPAs will have strict restrictions and some will essentially be closed off to all major use, including fishing. While the State is in charge of enforcing the new regulations, coordination between government agencies may provide additional help with an eye in the sky.

As much as the folks at NOAA might chafe at this description, it’s easy to think of these Twin Otter Survey Flights over the marine sanctuaries as a kind of “cop on the beat.” They’re not out there actively tracking down bad guys as much as they are a presence, keeping an eye on things and making sure everybody is on the up and up. And in that role, they don’t need to be flying everyday combing the ocean, monitoring everyone and every thing, every minute of every day. They may only survey the sanctuaries once every couple weeks. But knowing that today might be the day they are flying over, may help keep users of the marine sanctuaries in line. “Nothing to see here, move along.”

We’ve crossed these waters many times before for QUEST, but always traveling out into the deep blue on small, sea-sick inducing boats. I can tell you for certain, flying over the rough seas and into the wild blue, is a lot more pleasant and efficient. And seeing the Farallones from the birds eye view was clearly inspiring.

Watch the Marine Sanctuary Patrol Flight television story online.

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But even though it's in our own backyard, this place remains mostly unknown… probably due to its chilly temperatures. Let's face it, most of us are not donning our masks and snorkels and swimming in the hypothermic Pacific Ocean off our coast.

Lucky for us, some intrepid scientists and students are diving into this amazing place. Their job is to monitor how the ecosystems are responding to the new restrictions and protections taking place in the Marine Protected Areas. They gave us an amazing opportunity to see the natural world beneath the surface. And the world they shared with QUEST is truly inspiring. Playful harbor seals tease the divers while they weave through the gently swaying kelp forests. Fish dart through the rays of sunshine that cascades down to where starfish slowly go about their day. Through the eyes of these scientists, we witness the undersea life in bloom. They clearly have one of the best offices to go to work to each day.

Watch the Underwater Wilderness: Creating Marine Protected Areas television story report online.

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