Western Ecology Division

Around the Water Cooler: Tour of a King Tide

By Chris Janousek, PhD

Video taken during a king tide event shows a variety of tidal habitats in a forested estuarine valley in the Pacific Northwest. Marshes and rarer tidal swamp and scrub-shrub wetlands are shown. (Note: the video contains only background sounds; no narration or closed captions are included.)

For many years, one of my favorite activities as a marine scientist has been catching the early morning low tides along the rocky shores of the Pacific coast. The crisp salty air and the almost overwhelming diversity of intertidal marine life (not the 4 or 5 AM alarm clock) would inevitably make me glad I made the trip.

At EPA, my research has focused on the other end of the tidal range—the very highest parts of the intertidal zone where salt marshes and tidal swamps create a complex transition zone between truly terrestrial ecosystems and marine habitats like seagrass meadows. With other scientists at EPA’s Western Ecology Division lab, my work focuses on potential sea-level rise effects on coastal wetlands. Integral to understanding sea-level rise is studying high tide events.

Depending on location, North American coastlines have 1-2 high and 1-2 low tides per day. The most extreme high and low tides occur twice a month when the sun and moon are aligned linearly with the Earth. Tidal amplitudes also vary seasonally.

In the Pacific Northwest, the highest tides occur in the winter and can be up to a half meter higher than summer high tides. These are the king tides. In December 2012, we caught one of this winter’s king tides by boat while collecting water quality data in a tributary to one of Oregon’s largest coastal estuaries.

High water levels can be stressful to wetland organisms and humans alike. For organisms more adapted to life on dry land – plants and insects, for example – flooding may bring salt water, reduce soil oxygen and displace animals.

Excessive water levels also threaten developed land. The presence of wetlands in the high intertidal zone, however, creates a natural buffer protecting coastlines from damage by attenuating incoming wave energy. It is also during high tides that inorganic sediments are trapped by wetland vegetation, a process that helps these habitats maintain their elevation. Protecting and restoring such natural buffers along our coastlines may be especially valuable when high tides coincide with storm surges.

Data from both satellites and tide gauges show that sea-level has been gradually rising over the last several decades in step with other changes to the global climate. The magnitude of future sea-level change is still uncertain, but rising seas and king tides will continue to shape America’s coastal communities – both biological and human built.

About the Author: Chris Janousek, PhD is a coastal ecologist at EPA’s Western Ecology Division.

To learn more:

NOAA information about tides

Recent on-line scientific paper on vegetation’s role in attenuating coastal wave energy

EPA information on Sea Level Rise as a climate change indicator

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Science Wednesday: Ready for Takeoff

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

While I’ve come to expect extra scrutiny when flying, I was momentarily flustered when the pilot needed to know my weight so he could compute his preflight plans. (155 pounds.)

This morning I joined Eric Vance, EPA’s chief photographer, EPA scientist Steve Klein,  and U.S. Fish and Wildlife Service pilot V. Ray Bentley aboard a four-seat, single-engine plane for a flight over the Willamette River Valley in western Oregon.

arial view of winding riverThe landscape we flew over is the subject of the Willamette Ecosystem Services Project (WESP), an ambitious, large-scale, integrated, and multi-disciplinary research effort to quantify the benefits people derive from the environment. The study also focuses on exploring how human activities stress those benefits. The overall goal is to provide decision makers, stakeholders, and others across the Willamette River Valley with rigorous scientific information they can use to assess current conditions and plan for the future of their community.

All told, the Willamette River Valley Ecosystem includes some 7.5 million acres. To get a better picture of what’s happening across such a large area, it helps to get a bird’s eye view.

Time to fly.

arial view over trees and winding riverOur flight took us over the Willamette River as it winds from Corvallis to the suburbs of Eugene, a diverse and productive landscape. Over the drone of the engine and intermittent blasts of cool air that roared into cockpit when Eric opened his window to take pictures, Steve explained what he was seeing from a scientist’s perspective: how the flow and course of the river has been shaped by human forces, the patterns and types of forest and other natural habitats, what types of crops where growing in the large agricultural fields below, and the shifting boundaries between agriculture, forest, and what he referred to as “the built environment” (homes, roads, and industry, including the massive paper mill we could not only see, but smell—a thick, burnt-syrup kind of aroma).

My flight was just one of the many excellent experiences I’ve had this week visiting with scientists in EPA’s Western Ecology Division. I’ve learned about research projects as diverse as the 7.5-million-acre WESP, to plans to investigate the potential environmental impacts of things as tiny as those used in nanotechnology.

It’s been a great week and I’ll have lots to think about on the flight back to Washington. I won’t even flinch if the pilot asks me how much I weigh.

About the Author: Aaron Ferster is the chief science writer in EPA’s Office of Research and Development. He is the Science Wednesday editor, and a regular contributor.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.