cq v12n4 ches quart-2004 rev - chesapeake quarterly · n october 2003, a little-known think tank in...

CHESAPEAKEQUARTERLYCHESAPEAKEQUARTERLY

MARYLAND SEA GRANT COLLEGE • VOLUME 12, NUMBER 4

Digging into the Bay’s Ancient Past

In October 2003, a little-known thinktank in the Department of Defensequietly released a report warning that

climate change could happen suddenly —so suddenly it could pose a major threatto our country’s national security.

The title of the Pentagon report was amouthful: An Abrupt Climate ChangeScenario and its Implications for United StatesNational Security. Those implicationsincluded rising seas, flooded coastal cities,at least one drowned country, droughts,food shortages, failed states and fortressstates. The report was never designed as ascientific prediction. It was a speculativeeffort by defense strategists to dramatizeall the security threats the country wouldface if the climate suddenly shifted.

Why was the Pentagon suddenlyworried about abrupt climate change?Because new evidence from Greenlandshowed it had happened before.

On June 2, 2003, a French vessel designedfor deep-ocean research entered theChesapeake Bay, an estuary noted for itsshallow waters. On board were a dozenAmerican scientists, most of them geolo-gists or geophysicists who were hoping topunch coring tubes down into the bot-tom of the Bay and bring up sedimentsburied there before the estuary formed.

CHESAPEAKEQUARTERLYChesapeake Quarterly explores scientific, environ-mental, and cultural issues relevant to the ChesapeakeBay and its watershed.

This magazine is produced and funded by theMaryland Sea Grant College Program, whichreceives support from the National Oceanic andAtmospheric Administration and the state ofMaryland. Editors, Michael W. Fincham and JeffreyBrainard; Science Writer, Daniel Strain; ProductionEditor and Art Director, Sandy Rodgers. Send itemsfor the magazine to:

Maryland Sea Grant College4321 Hartwick Road, Suite 300University System of MarylandCollege Park, Maryland 20740301.405.7500, fax 301.314.5780e-mail: [email protected] www.chesapeakequarterly.net

contents2 The Day Before Yesterday

What happened when abrupt climate change came to the Bay?

8 The Chesapeake’s Excellent FossilsCliff finds yield insights into prehis-toric creatures, including whales.

14 Saving Calvert CliffsEfforts to control erosion may threaten the cliffs’ unique geology.

Cover photo: On board the RV MarionDufresne, a French research vessel, a deckworker gets ready to drop the giant Calypsocorer, a sampling device that can drive deepinto the bottom of the Chesapeake Bay.PHO TO GRAPH, JENNEY HALL

December 2013

Volume 12, Number 4

When abrupt climate changecame to the Chesapeake Bay

Michael W. Fincham

THE DAY BEFOREYESTERDAY

The American scientists had questionsabout past climate changes and the sedi-ments might hold answers — or at leastclues. “We were trying to learn moreabout the long-term history of theChesapeake Bay,” says Debra Willard ofthe U.S. Geological Service. Sediments, ifyou know how to read them, have a storyto tell: they catch and hold the remnantsof whatever washed into the Bay onceupon a time or blew into the Bay orlived and died in these waters. One ques-tion the scientists were asking: how hasclimate change shaped the evolution ofthis estuary?

To answer their questions, theAmerican scientists had chartered theRV Marion Dufresne for 48 hours ofround-the-clock coring work. The shipwas big, 395 feet long, and it offered five-course French cuisine complete withwaiters, wine, cheese plates, and pastries. Italso carried the gear and staff that couldtake very deep core samples. Managed bythe Institute Polaire Paul Emile Victor(IPEV), the ship had two key missions: tocarry supplies to French research stations near Antarctica and to mount expeditionsaround the world to uncover evidence ofclimate change.

“It was the only ship that had thecapability to get long continuous cores,”

says Willard. A research geologist withexpertise in buried pollen, she coordi-nated the expedition for the cadre ofAmerican scientists, most of them fromthe U.S. Geological Survey (USGS) andthe Naval Research Laboratory. The RVMarion Dufresne came equipped with sci-ence laboratories, high-end computerworkstations, and huge cranes, but itssecret weapon was the Calypso corer, oneof the longest, heaviest coring samplers inthe world.

With all that gear, the Americansplanned to capture the deepest sedimentsamples ever taken in the history of

Chesapeake Bay science, evidence thatcould hold clues about earlier climatechange in the Chesapeake.

Ten years ago the specter of abruptclimate change seemed to invade theAmerican mind-set rather abruptly.Perhaps it was a reflection of post-9/11fears about how fast the future could turngrim, but a lot of serious people weresuddenly talking about it.

The Pentagon report on abruptclimate change was commissioned byAndrew Marshall, long-time director of athink tank called the Office of Net

Assessment. Press reports usually calledMarshall the “Yoda” of the Penta gon, andForeign Policy magazine in 2012 called himone of the world’s top global thinkers.Now 92 years old, Marshall is still on thejob, and a big part of his job is still thesame: thinking about the unthinkable andreporting his thoughts directly to his boss,the secre tary of defense. In 2003 one ofhis thoughts was that the country shouldnow take seriously the possibility ofabrupt climate change.

He had this thought because he knewthat many scientists were beginning totake the idea more seriously. Only the

Volume 12, Number 4 • 3

Age (Thousand years before present)

Tem

pera

ture

ove

r G

reen

land

(°F

)

-20

-30

-40

-50

-6015 10 5 0

Medieval Warm Period

Little Ice Age8,200-Year Event

Holocene Epoch

Thomas Cronin, a research geologist, (above) collaborated with colleagues at the U.S. Geological Survey, who analyzed sediment cores from theChesa peake Bay and found evidence of abrupt climate change during the early evolution of the estuary. Ice core indicators (above) show that the Holocene,our current interglacial epoch, began some 11,000 years ago and brought a time of stable temperatures, interrupted by a cool-down 8,200 years ago andlater by the Medieval Warm Period and the Little Ice Age. PHO TO GRAPH, MICHAEL W . FINCHAM; GRAPH, ADAPTED FRO M RICHARD B. ALLEY , THE TWO-MILE TIME MACHINE

year before, the National ResearchCouncil had released a 2002 study warn-ing that climate change could occurquickly, within decades, especially ifsomething happened to slow down orshut down the Atlantic MeridionalOverturning Circulation, the ocean con-veyor belt that, among other missions, car-ries heat from the tropics up into theNorth Atlantic. After Marshall read thescientific study, he commissioned his ownstudy and hired Peter Schwartz and DougRandall, two self-described futurists, towork out a geopolitical scenario.

Hollywood producers were also skim-ming those science reports, skipping anyinconvenient details about the speed ofclimate change. In 2004 they created theirown vivid version of abrupt climatechange by releasing a 125-million-dollarmovie, The Day After Tomorrow. For geolo-gists, abrupt change usually took severaldecades, for filmmakers it only took sev-eral days. Unleashing the power of digitalspecial effects, they showed New YorkCity succumbing to a new ice age in thespace of three weeks, a climate change soabrupt and so devastating it sent the U.S.government decamping to Mexico.

What was the scientific evidence for“abrupt climate change” in the past? The

Pentagon modeled its nightmare scenarioon a specific episode that struck theplanet some 8,200 years ago. The earthwas well into our current interglacial era,an age of warming oceans and melting icesheets, when a major cool-down suddenlyarrived. It’s called the 8.2 kiloyear event— or the 8.2 ka event in scientific short-hand. It dropped temperature averages inGreenland 38 degrees Fahrenheit in lessthan 20 years and it altered ocean cur-rents, atmospheric circulation, andweather patterns around most of theplanet. In geological time scales, that’sabrupt.

The first evidence for the 8.2 kiloyearcooling was found in ice cores inGreenland, but on board the MarionDufresne Tom Cronin and Debra Willardsuspected there might also be evidenceburied in sediments below theChesapeake Bay.

As the French ship dropped anchorfor its first coring site, Cronin found aspot along the high walkways that hangabove the stern deck so he could watchthe work crew below prepare the sam-pling gear. Tall and fit with graying hairand strong opinions, Cronin is a researchgeologist who joined the USGS in 1978

and has been publishing prolifically eversince on climate change, sea level rise,estuary formation, and ocean circulation.Gathered to watch with him along thewalkways were most of the American sci-entists. Each “core drop” from this kindof ship represented a rare opportunity forgathering deeper sediments and deeperinsights into the evolution of the estuary.

The heavy lifting on this ship washandled not by the American or theFrench scientists, but by a crew of 20Malagasians recruited from the island ofMadagascar, a former French colony.Working the deck in hard hats, theyhooked together several pipes into oneextended tube, craned it up to the coringplatform, and dangled it over the side likea long ice pick. There they could top loadthe ice pick with weight, up to 10 tons ofweight if needed. On deep-ocean drops,all that weight has driven long tubes 230feet beneath the ocean floor.

Their hopes for a deep drop took a hit

4 • Chesapeake Quarterly

The deck crew of the Marion Dufresne raises the Calypso corer that captured the longest contin-uous sediment samples ever taken in the Chesapeake Bay. A researcher (right) withdraws a sample toanalyze the chemistry of pore water trapped in long-buried sediments. Debra Willard (opposite page),the research geologist who coordinated the research cruise, has analyzed sediment cores like this tochart changes in forest populations and the arrival of major drought eras during our current inter-glacial epoch. PHO TO GRAPHS: ABO VE AND RIGHT , FRENCH PO LAR INST ITUTE IPEV ; O PPO SITE PAGE, MICHAEL W . FINCHAM

at the first site. The coring pipe drove intothe bottom and smacked against a barrierof hard sand. When the Malagasian crewwinched it back up and laid it on deck,the American geologists found a badlybent core pipe, holding only a short stubof sand. That hurt. Willard and Croninhoped an ice pick in that spot would jaball the way down into sediments buriedduring the last ice age.

Deep cores, however, are hard to comeby in the Chesapeake Bay. To drive veryfar into bottom sediments, a coring tubeneeds a lot of deep water. And that’s theproblem: a shallow-water estuary requiresshorter coring tubes and shorter drops.On this trip, three more core pipes wouldcome up holding short stubs with 2.7feet, 2.9 feet, and 8.1 feet of sediment.

“Coring the Bay is very much likefishing,” said Peter Vogt, a marine geo-physicist with the Naval ResearchLaboratory who helped pick out coringspots. When the Marion Dufresne kept fish-ing, casting 10 coring pipes in all intoChesapeake waters, the crew eventuallylanded some big catches: a 42-foot corealong the eastern side of the lower Bay,

then a 52-footer nearby, a 55-footer off the Patuxent River,two 60-footers off the mouth ofthe Potomac, and along KentIsland, they raised an 80-footsediment core, the longest sedi-ment core ever landed in theChesapeake Bay.

For Cronin, the third coredrop was the charm. In the bluetwilight of an overcast eveningthe ship dropped anchor alongthe eastern side of the lower Bay,and at 10:05 p.m. the core pipesplashed down into dark waters.This would not prove thelongest core drop at 52.5 feet,but it hauled up strong evidencethat the 8.2 kiloyear coolingonce came to the Chesapeake.

With this core Cronin andcolleagues would insert a newchapter into the oft-told storyabout the origins of the Chesa -peake Bay. According to the

accepted account, the Bay was coming tolife as the last glacier era was dying out.When the great ice sheets began meltingsome 15,000 years ago, sea levels beganrising, creeping across the continentalshelf, steadily drowning the lower rivervalley of the ancient Susquehanna River.Roughly 10,000 years ago, the oceanreached the area we now call Norfolk,and pushing north the seawater beganturning the lower river into a brackish-water estuary. By 3,000 years ago theestuary reached 190 miles north to Havrede Grace, Maryland.

The new chapter in this story is the8.2 ka cooling. It came early in thisprocess, and evidence of its abrupt arrivalcan be seen in the ups and downs ofmarsh growth in the evolving estuary. Asbrackish waters began pushing north,marshes were accreting steadily along theborders of the new estuary, keeping pacewith rising sea levels. Around 9,000 yearsago, however, sea level rise accelerated,and many marshes, unable to keep up,began drowning. It would take the abruptonset of the 8.2 ka cooling to slow therate of sea level rise and revive marsh

growth. Marsh accretion could once againkeep pace with the rising water.

That’s the story Cronin and Willardand their colleagues were able to extractfrom the sediments in core MD03-2656.They carbon-dated key sections of thecore and probed its mud for microfossilsof plants and animals. They were lookingfor large groupings and large gaps in pop-ulation numbers, evidence that would tellthem when certain plants and animalsflourished and when they faded. Willardfocused on pollen, Cronin on animals.Knowing the salinities and temperatureranges for their microfossils, they coulduse these groupings as indicators forchanges in rainfall, salinities, temperatures,and sea level rise.

When saltwater protozoa suddenlyflourished, for example, and certain sedgegrasses suddenly faded, they could say sealevel was rising fast and marshes were dis-appearing. When the signs reversed, whenprotozoa numbers dropped and sedgegrasses reappeared, “we interpret that as aslowdown in the rate of sea level rise,allowing marshes to grow,” says Cronin.And the cause for the slowdown: the bigcooling, the 8.2 kiloyear event.

What could bring on such an abrupt cli-mate change? It’s easy to see how thesudden onset of the 8.2 ka cooling couldlead to the Pentagon’s nightmare sce-nario. It could also, perhaps, inspire yetanother Hollywood film, let’s call it TheDay Before Yesterday. It would open withan aerial shot gliding over a huge lakethat once covered much of America’sGreat Plains and parts of Canada (see lakemap, p. 7). Some 9,000 years ago, LakeAgassiz was sitting in a depression leftbehind by the retreat of the Lauren tideice sheet that once stood two miles high,mashing down parts of the United Statesand all of Canada.

That depression was now brimmingwith meltwater from the retreating icefield, eventually holding a small ocean offresh water, some of which leaked southalong the Mississippi River basin.Rimming the lakes on the north andeast, however, were the ramparts of the


retreating Laurentide. They stood like agreat white dam, holding back all thatfresh water.

In a still-warming world, that dam hadto burst. And sometime well before 8,200years ago, it did, probably several timesand in several places. That dam breakkicks off Act II in our movie: icy waterrushes through the breaches, hugeamounts of water, something like 50Amazon Rivers, according to Cronin. It’sprobably headed out through HudsonBay, the St. Lawrence River, and theMackenzie Straits.

Scientists call this a “catastrophicrelease.” When this huge flood of freshwater hit the saltwater oceans of theNorth Atlantic, it caused a catastrophe: itcollapsed the Atlantic Meridional Over -turn ing Circulation (AMOC), the greatconveyor belt that carries warm and coldwater around the globe. The conveyorusually pumps warm, salty waters out ofthe tropics into northern regions wherethe water cools off, increases in density,and sinks, pushing cold water southwardsin deep, cold underwater currents. This“overturning” system not only circulatesheat around the globe: it also drivesatmospheric circulation that largely con-trols weather patterns.

What happens to this conveyor whena tsunami of meltwater arrives? “You areflowing a lot of warm water up north,”says Cronin, “and all of a sudden youthrow this fresh water on top, and youlower the salinity and the density.” Waterthat is less salty gains buoyancy and losesdensity. It doesn’t sink as easily. In effect, itturns off one of the heat pumps for theplanet.

The result: less Gulf Stream heatreached the high latitudes, atmosphericcirculation was altered, sea level riseslowed down, and effects were felt aroundmuch of the globe. For the movie, it’s theperfect Act III plot reversal: the warmingof the planet unleashes the cooling of theplanet.

And there were more plot twists onthe way. The glacier lakes finally drainedout, the Atlantic Meridional OverturningCirculation (AMOC) recovered and stabi-

lized, heat flowed again to the NorthernHemisphere, the big 8.2 ka cooling beganto wane, and sea levels began to rise again.In the Chesapeake, marshes began drown-ing for a second time.

There was a happy ending, of sorts,and not just for marsh lovers. Sea levelrise began to slow down and stabilizearound 7,000 years ago, enabling marshgrowth to flourish again in the Chesa -peake and setting the stage for a majortransition in human history. According toscientists like John Day of Louisiana StateUniversity, the rise of urban, state-gov-erned societies began in coastal villagesand cities that located alongside estuariesand the lower flood plains of major rivers.Think the Tigris-Euphrates in Iraq, theNile in Egypt, the Yellow River in China.The rich biological productivity of newlystable coastal areas, says Day, helpedunleash the social productivity behind theemergence of early civilization.

What would be the fate of our currentversion of civilization if a climate changeas abrupt as the 8.2 kiloyear coolingarrived sometime soon? The question washard to answer 10 years ago whenAndrew Marshall commissioned hisPentagon scenario. In 2002 the NationalResearch Council (NRC) said there wasvirtually no research on the economicand ecological impacts of abrupt climatechange. A year later a report published bythe Royal Society of London came to thesame conclusion.

The authors of the Pentagon reportwere, in effect, “first in the field” to con-sider the social and political impacts ofsudden climate change. But they wereoffering informed speculation rather thanscientific research. Their goal was to createa geopolitical scenario chock-full ofwhat-if speculations — all designed tospur new thinking about threats toAmerican society and security.

What if, for example, the ocean con-veyor belt were to collapse in the nearfuture as it did in the not-too-distant past?The climate effects would include tem-perature drops in North America, Europe,and Asia, coupled with some temperature

rises in Australia, South America, andSouth Africa. Europe could become likeSiberia. Coastal cities like The Haguecould be flooded out, and countries likeBangladesh could become uninhabitable.China could have less predictable mon-soon cycles, colder winters, hottersummers , and food shortages leading tofamine. The United States could faceshorter, less productive growing seasonsand suffer larger floods, especially inmountain regions, and more intense forestfires. Southern countries could suffer less.Australia, for example, could remain amajor food exporter.

The geopolitical upheavals wouldinclude food and water shortages, massemigrations, wars for resources, andrealignments among “have” and “have-not” nations. Would Australia and theUnited States become “fortress nations?”Would the U.S. and Canada eventuallymorph into one nation to better controltheir borders?

The main point of all these specula-tions was a “shock and awe” attack on the“gradual change view,” the belief thatclimate change would come slowly. Thatnations could adapt.That they would havetime to increase food production.Thatthey would find technological solutionsfor water shortages.

In the last 10 years, the “abruptchange view” has been drawing moreattention from the American scientificcommunity. The 2002 report by theNational Research Council was fol-lowed by a 2008 report by the U.S.Climate Change Science Program, andmost recently the NRC weighed inagain with a study released in December2013. The new study goes by the title,Abrupt Impacts of Climate Change:Anticipating Surprises, and it calls for theU.S. government to create an earlywarning system that would carefullymonitor key earth systems for subtlesigns of “tipping points” that couldunleash sudden climate changes.

This latest NRC report claims to bethe first to examine the research onhuman, social, and economic impacts. Thestudy was developed in collaboration with


the U.S. intelligence community and itconcurs with many of the non-scientificspeculations in the earlier Pentagonreport. Food scarcity and famines, epi-demics and pandemics, mass migrations,political instability and wars could allensue in the aftermath of a sudden cli-mate shift. The national security chal-lenges would be daunting, and the NRCrecommended the “excellent discussion”of those challenges found in the DefenseDepartment report ordered up a decadeearlier by a “Yoda of the Pentagon” whowanted to spark new thinking.

What were the lessons of the long coresthat came out of the bottom of the Bay?

In 2003 the Marion Dufresne ended itsChesapeake cruise at a dock in Baltimorewhere the French staff threw a wine-and-cheese party for the American scientists.The next day the Malagasian crew lifteddozens of core samples out of the ship’shold and loaded them on trucks destinedfor the Reston laboratories of the U.S.Geological Survey.

Out of those cores is coming a revisedaccount of the evolution of the estuary,

one that includes better dating of keyevents, more details, and a new chapter onthe arrival of the 8.2 kiloyear cooling inthe Chesapeake. With their pollen studies,Willard and her colleagues outlined theshifts in forest communities that camewith earlier shifts in temperatures and sealevels. They also identified five majordroughts, each lasting several centuries,that struck the region over the last 8,200years.

Findings like these also undercut thegradual change view that seemed tounderlie earlier stories about the Bay’sevolution. “The rate of sea level rise in theChesapeake was not constant as the Baywas flooding,” says Cronin. “It was kind ofstaccato” with several “oscillations andhiccups.” Some of those oscillationsarrived gradually. The 8.2 kiloyear cool-ing, the big hiccup, arrived abruptly.

The evidence of past climate changein the Chesapeake and in other parts ofthe planet is sketching a dicey picture ofour current interglacial epoch. TheHolocene has endured episodes of climatevariability kicked off not by humaninputs, but by natural forces, by interlock-ing shifts in ocean dynamics and atmos-pheric circulations and solar inputs.According to Cronin, “the interglacial thatwe live in, that we perturb with CO2,wasn’t nearly as stable as some peopleused to think.”

And the odds are the future may notbe so stable either. The good news isthat the latest NRC report downgradedthe chances that the ocean conveyorbelt would collapse anytime soon. Theworrisome news is that it also elevatedthe odds that other abrupt changescould be in the works. The Laurentideice sheet is gone, but the glaciers inGreen land and the ice sheets inAntarctica are still here and they arehuge and they are melting.

How fast they are melting is a trickyquestion that scientists are struggling toanswer. It seems the meltwater they holdcould unleash a climate hiccup not seensince that long-ago 8.2 kiloyear eventsuddenly cooled off a warming world.

— [email protected]


ANTARCTICA

AUSTRALIA

ASIAEUROPE

NORTHAMERICA

NORTHAMERICA

SOUTHAMERICA

AFRICAPACIFICOCEAN

PACIFICOCEAN

ATLANTICOCEAN

SOUTHERN OCEAN

SOUTHERN OCEAN

INDIANOCEAN

Norwegian-Greenland Sea

ARCTIC OCEAN(covered by winter ice)

GULF STREA

MARCTIC CIRCLEARCTIC CIRCLE

Sinking Cold,Salty Water

Sea to AirHeat Transfer

Global Ocean Conveyor Belt

What Caused Abrupt Climate Change?

The great ocean conveyorbelt is driven by density differ-ences created by temperatureand salinity. Warm, saltywaters flow out of the tropicsalong the surface, pumpingheat into the atmosphere innorthern latitudes. As the sur-face waters cool, densityincreases, and these waters sinkinto bottom currents that movesouth towards Antarctica. Thatconveyor belt seems to haveslowed several times in thepast, as North Atlantic waterswere suddenly flooded withfresh, low-salt, low-densitymeltwater that was too buoyant to sink. The water came from great inland glacial lakes likeLake Agassiz that probably released meltwater through Hudson Bay, the Saint Lawrence River,the Mississippi River, and the MacKenzie Straits. MAP ILLUSTRAT IO NS: GLO BAL O CEAN CO NVEYO R BELT ,

SMITH SO NIAN INST ITU T IO N; LAKE AGASSIZ, CO URTESY O F MICHAEL LEWIS AND JO HN SHAW, GEO LO GICAL SURVEY O F

CANADA ATLANTIC , DARTMO UTH NS, CANADA

LAKEAGASSIZ

Ice cap melting8,200

yrs. ago

Discoveries in Bay cliffformations are yielding

new insights intoprehistoric creatures,

including ancient whales

Daniel Strain

THECHESAPEAKE’S

EXCELLENTFOSSILS

Nearly 14 million years ago off the Atlantic Coast, an ances-tor of today’s whales died. It might have been attacked bya predator or simply succumbed to old age and disease.

Either way, the whale sank 100 feet or more to the sea floor below.There, it provided a feast for scavenging sharks and microbes.

Over time, mud and sand trickled down to the sea floor, bury-ing the whale from head to fluke. It wouldn’t be seen again untilJuly 2013, when an amateur fossil hunter spotted what looked likea jawbone poking out of a cliff face on the shores of the PotomacRiver.

Stratford Cliffs straddle the Potomac along a short stretch ofVirginia’s Northern Neck. At their peak, they rise to more than100 feet high. Jon Bachman had been searching for sharks’ teethand other fossils on the beaches below those cliffs when he stum-bled across the fossilized bone. The large mandible was just visiblein the tan cliff face.

Fortunately, not far away lived a paleontologist with a long-timeinterest in the cliffs, and he knew what to do next. StephenGodfrey, the curator of paleontology at the Calvert MarineMuseum in Solomons, Maryland, began the excavation of the jaw-bone — which turned out to be much more. Over several weeks,the team, which included a host of volunteers, unearthed from thecliff face an entire whale skull, measuring six feet from front toback. Along with it came many other bones: vertebrae, pieces ofribs, a humerus from right below the whale’s shoulder, and part ofa flipper bone. For paleontologists, to find so many fossilized piecesof a single whale in one place constituted a bonanza.

The leviathan’s remains may seem like an unusual thing to dis-cover around the Chesapeake Bay, but the region has long beenknown for producing plentiful fossils of marine life, includingwhales. Most have come from the Calvert Cliffs, located inMaryland about 25 miles northeast of the Stratford features.

Part of the same geologic formation as the Stratford features,Calvert Cliffs run 30 miles down the Bay’s western shore, beginningnear the town of Chesapeake Beach and ending by Drum Point onthe Patuxent River. The cliffs — which turn golden during sunrise— and their surrounding beaches in Calvert County are known forfossilized sharks’ teeth and other prehistoric remains. Look closely,and you’ll find an explosion of life recorded in stone: whale fossils,yes, but also ancient sand dollars, pecten scallops, and twisting shellsfrom sea snails. These animals all lived during a geologic epochcalled the Miocene, which lasted from about 23 to five million yearsago. It was an important period in the evolution of whales.

Many people might consider those leavings mere souvenirs, butfor paleontologists, the cliffs along the Chesapeake rank among themost important research sites in the Mid-Atlantic region. Fossilsfound here have certainly contributed much of what we knowtoday about the planet’s Miocene seas. For generations, scientistshave walked the cliffs, building a better and better picture of whatthose ancient oceans would have looked like: what creaturesplumbed the oceans millions of years ago, and how did they live?The evidence there has even helped scientists understand whysome modern whales lack a sense of smell.

Calvert Cliffs, seen here risingfrom the Chesapeake Bay by Rocky

Point, are a scenic landmark.PHOTOGRAPH COURTESY OF STEPHEN GODFREY,

CALVERT MARINE MUSEUM


“Okay, that was a good day,” says scientist Stephen Godfrey(top), holding a fossilized whale backbone that’s been wrapped inplaster. He spent much of his morning carefully digging around thisfossil (middle), which was found at the base of Stratford Cliffs inVirginia. This fossil, like others found along Stratford or CalvertCliffs, dates back to the Miocene epoch (see time scale above). Thisgeologic epoch was important in the evolution of whales. PHO TO GRAPHS,

DANIEL STRA IN; T IME SCALE ADAPTED FRO M A USGS GRAPHIC

When it comes to the history of life on earth, the Chesapeake’scliffs are “particularly good at telling part of that story,” Godfrey says,“allowing us to get a really good picture of the diversity of organismsand what they looked like.”

Amazing Objects

On a sunny October morning, the beach where Bachman discoveredthe latest of the Bay’s famous fossils this past summer is quiet. OnlyGodfrey and a volunteer, a long-time fossil hobbyist named MarcoGulotta, are working here today. The two have returned to this sandyspot in Virginia to dig for parts of the whale that had been left behindwhen the skull was originally removed.

The nearby Potomac River is as smooth as gelatin. Godfrey, wear-ing waterproof waders and a flannel shirt, is crouching down in frontof a waist-high hole in the sand-colored cliff face. He and Gulottahad recently carved out this small cave, using a gardening hoe andscrewdrivers to chip away at the soft, clayey sediment.

“Now at the back of the hole, you can see the brown bone backthere. That’s a vertebra,” Godfrey says. “That’s our goal for the day.”

The backbone, which is about the width of a basketball, lookssolid now, but Godfrey will need to be careful getting it out. Afterhaving been buried under sediment for millions of years, fossils likethis one often fall apart into many pieces when picked up, Godfreyexplains. To avoid that, he will scrape gingerly around the fossil,exposing all of its sides. Then, he’ll cover it in bandages coated withplaster — the same bandages that doctors use to mold plaster casts forbroken bones. That should keep the vertebra together.

For Godfrey, the work of extracting this bone — and the patienceit will require — are worth it. “For me, at the heart of this is anamazing object,” Godfrey says. “I want to know what it is, and I wantto extract as much information as I can.”

In that sense, he’s far from alone: Calvert and Stratford cliffs havelong been a valuable resource for scientists hoping to extract informa-tion about the planet’s prehistoric seas. The first fossil from here topop up in the scientific literature was the shell of a sea snail, illustratedin a 1770 natural history tome, according to the Maryland GeologicalSurvey. And as the catalog of fossils collected from the cliffs grew overthe centuries that followed, scientists gained a more complete under-standing of life during the Miocene epoch.

The span of time may lack the cultural cachet of other periodslike the Jurassic when dinosaurs roamed the earth. But the more sci-entists learn about the Miocene, the more they are able to grasp itsimportance in the evolution of many marine organisms.

Those organisms would have swum or rested in salt water thatwas much warmer than are today’s oceans, scientists say. Because ofhigh sea levels, a stretch of the Atlantic Ocean, called the SalisburyEmbayment, extended far inland over the East Coast, all the way towhere Washington, D.C., currently stands. Crocodiles, dolphins,and sharks the size of school buses flourished in this muggyenvironment .

New species of whales emerged during this period, marking thetransition of the species from animals that had one “fin” on land andthe other in the water to true ocean mammals. Biologists use the

Geological Time ScaleEra Period Epoch Duration

CenozoicAge of

Mammals

QuaternaryHolocene

11,700 yrs ± 99

2.588 million yrs

5.332 million yrs ±0.005







251.0 million yrs ± 0.4


Pleistocene

Tertiary

Pliocene

Miocene

Oligocene

Eocene

Paleocene

MesozoicAge of

Reptiles

Cretaceous

Jurassic

Triassic

Paleozoic

Proterozoic

term “radiation event” to describe therapid appearance of several new speciesfrom one or more ancestors.

“You’re right on the cusp of whereyou went from Archaeocetes, those aresome of the very early whales,” saysRalph Eshelman, a paleontologist and thefounding director of the Calvert MarineMuseum. “And you begin to have thisvast radiation where you’re getting intothe kinds of whales that you have today.”

Much of that life is captured inCalvert Cliffs. To date, paleontologists,working for more than a century alongthe cliffs, have catalogued and namedmore than 600 fossil species of all types,including mollusks, sharks, birds, and ofcourse, whales.

The journey of those remains fromocean to museum display case was a longone: like the Stratford whale, these organ-isms died and sank to the bottom of theSalisbury Embayment during theMiocene. As temperatures cooled towardthe end of that epoch, sea levels aroundthe globe fell, and the ancient embay-ment shrank away.

Over time, however, waters rushingover the area where the Chesapeake isnow cut their way into that old sea floor,forming what became Calvert Cliffs.Today, this erosion continues to eat awayat the precipices, causing the cliffs torecede at a steady clip. While that erosionpresents perils to people who live nearby(see Saving Calvert Cliffs, p. 14), it alsocontinuously unearths new specimens forfossil hunters to find and catalog.

The cliffs, then, provide scientistswith the means to look back throughtime, helping them understand how fos-silized organisms from the Miocene fitinto the broader history of life on earth.

The key to doing that lies in the cliffs’geology.

If you look closely at the faces of theCalvert Cliffs, you can see distinct bands,or strata, bearing sediments in differentcolors running across the surface — PeterVogt, a retired geologist who lives inCalvert County, likens the cliffs to a“layer cake.”Those layers, in turn, alsofunction like a sort of timeline.

It works like this: through decades ofstudy, researchers have roughly estimatedthe age of the various strata in theChesapeake’s cliffs. They’ve done thatmostly by searching through the cliff lay-ers to find “index fossils.” In general,these fossils, which are often types ofmollusks or single-celled organisms, areknown to have flourished at only onepoint in the history of life on earth. Thatmakes them a shortcut for dating geo-

logic strata: if you find the right indexfossil at a certain point in your cliffs, forinstance, then you can roughly estimatethe age of the whale skull sitting nearby.

Scientists have split the geology ofCalvert Cliffs into three main groups oflayers, or formations: the Calvert, Chop -tank, and St. Marys formations. The oldestof the three, the Calvert Forma tion, sits atthe base of the cliffs. That’s about whereJon Bachman found his whale. These lay-ers reach back to about 18 million yearsago and represent the Miocene at itswarmest. Temperatures then were aroundsix degrees Fahrenheit warmer than theyare today.

By the time you reach the St. MarysFormation, the youngest of the bunch, theMiocene oceans had begun to cool. Thoselayers, found at the top of the cliffs, stoparound eight million years ago, coinciding

A fertile habitat for dolphins, sharks, and manatee-like mammals called dugongs, the SalisburyEmbayment (above left), part of the Atlantic Ocean, covered whole portions of modern-day Marylandduring much of the Miocene. The sediments that lay at the bottom of the ancient embay ment nowmake up the geologic formations visible in Calvert Cliffs (above right), shown here in a generic cross-section of the outcrops. The cliffs are split into bands, or strata, made up of different types of sediment.Within each formation is evidence of fluctuations in climate. You tend to see more sands duringcooler periods and more clay and silt during warmer ones. ILLUSTRAT IO NS ABO VE, REDRAWN BY SANDY

RO DGERS FRO M FIGURES IN CLARK ET AL. 2004; MAP O N O PPO SITE PAGE, ISTO CKPHO TO .CO M/UNIVERSITY O F TEXAS MAP LIBRARY


silty finesand

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with the disappearance of many warm-weather-loving organisms from Maryland— why, perhaps, you don’t see crocodilesaround the Bay anymore.

Worldwide, there are few locales thatcarry such a long-running record ofmarine organisms in the Miocene, scien-tists say. In addition to the Calvert Cliffsregion, paleontologists have also dug uprich veins of marine fossils in sea cliffsaround Antwerp, Belgium and a set ofdesert outcrops in Peru. But Marylandscientists argue that their paleontologicalsites are the best: fossils found here havetended to be older than those from Peruand in better condition than fossils fromBelgium. The cliff chain “really deservesbeing considered one of the most impor-tant geological localities on the East Coastof the United States,” Eshelman says.

David Bohaska, a collections managerfor vertebrate paleontology at theSmith sonian Institution’s NationalMuseum of Natural History, agrees. Hefirst encountered the fossils of CalvertCliffs on a seventh-grade field trip. “As akid, reading about dinosaurs and such,you always think of the Gobi Desert orexpeditions out west,” says Bohaska, whogrew up in the Towson area. “I’m aproud Mary lan der. It’s kind of neat thatmy home state is, in fact, famous forsome of its fossils.”

The First Museum

Stephen Godfrey, who joined the CalvertMarine Museum in 1998, has probablydone more than anyone in recent yearsto find new information about thosefamous fossils. And just as his fossilsundertook a long journey before reachingthe museum, so did he.

Today the modest scientist works outof an office near the museum’s mainexhibit hall by the water in Solomons.The room is a testament to his love ofnatural history. On the walls and shelvesare paintings of melting glaciers and amodel of a Brachiosaurus skull — all piecesmade by the scientist, who moonlights asan amateur artist and sculptor. On his wayin, he affectionately pats the head of amodel of a baby duck-billed dinosaur

that’s knee-high and painted green. “Thiswas my first,” he says.

That love of piecing together animalsstarted early. As a child, Godfrey becametaken with the idea of founding his ownmuseum.

“My bedroom was transformed into amuseum: seashells, insects, anything.Fungi, whatever I could collect,” Godfreysays. “I would label all these things. Myroom, I kid you not — I had things hang-ing from the ceiling.”

He particularly liked skeletons, findingthe raw materials he needed to build hisown from road-kill specimens: raccoons,dogs, and other assorted animals. Usingglue and wire, plus a textbook of animalanatomy loaned to him by his uncle,Godfrey would meticulously rebuild theanimals’ injured skeletons — bringing thecreatures back to life. Sort of.

But the budding scientist’s upbringinginitially steered him away from a career inpaleontology. Godfrey, whose parents weredevout Christians, was raised as a young-earth creationist. For much of his youth,he believed that the world was only a fewthousand years old and rejected the sci-ence of evolution. When he became agraduate student in paleontology, it wasn’t

to dig up dinosaurs but to evaluate forhimself whether the evidence presentedfor evolution in textbooks had merit.

But Godfrey got lucky: as a student, hewas invited on a paleontological expedi-tion to a quarry in Kansas. There, mem-bers of the expedition uncovered numer-ous slabs of rock that still bore the foot-prints of prehistoric lizards that livedduring the time of the dinosaurs. “Wecame upon these little imprints, and, forme, it was just earth-shattering,” he says.

The scientist, who now talks passion-ately about the deep history of life, stillkeeps one of those rock slabs in a filecabinet in his office. He takes it out andtraces the imprints, no bigger than what apigeon would leave behind, with his fin-gers. “You can see the little toes,” he says.“Front foot, back foot.”

Oceans of Whales

These days, the former creationist isn’tdabbling in dino footprints. But his workaround Calvert Cliffs has given him thechance to help build on what scientistsknow about the history of life on earth— albeit a small bit of it.

He’s thrown himself especially intothe study of whales. And for good reason:near the middle of the Miocene, therewere more species of whales alive than atany other time, including the present. Thecreatures’ success likely comes down towarm ocean temperatures, says OlivierLambert, a paleontologist specializing inwhales at the Royal Belgian Institute ofNatural Sciences in Brussels. The balmyconditions seen during the Miocenewould have supported huge schools offish and other whale food.

And at the time, new species ofwhales were emerging, while older oneswere drifting toward extinction. Long-snouted dolphins, small whales withunusually long snouts, for instance, can befound in Calvert Cliffs’ older layers. Butas you move forward in time, they slowlydwindle, then disappear entirely for rea-sons that are still unclear.

On the flip side, most of the modernfamilies of whales that we see today aroseduring the Miocene. The epoch saw the


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first relatives of modern dolphins, por-poises, beaked whales, and narwhals. TheRorquals, a family that today includesblue whales, and right whales also cameinto existence around this time.

In all, scientists have catalogued andnamed 28 species of fossil whales found atCalvert Cliffs, marking different periodsin the evolution of these creatures. Today,only around 80 species of whales swimthe seas worldwide.

Now, one of the challenges facingGodfrey and his colleagues is to identify asingle fossilized whale — the one foundby Jon Bachman in Virginia.

For now that specimen — owned bythe foundation behind Stratford Hall, thehistoric estate where the whale was found— is being kept at the Calvert MarineMuseum. Having run out of space in hislab, Godfrey installed the skull in one ofthe museum’s exhibit halls. It’s next to awall-sized display illustrating the entirehistory of life on earth.

The skull is lying upside down, withthe roof of its large maw visible to guestspassing by. In life, this whale might havestretched out to around 25 feet long. Thatputs it at about the same size as a mod-ern-day minke whale. At this point in theMiocene, Godfrey says, whales had yet tohit the mammoth sizes of species alivetoday like blue whales. Shrimpish or not,the skeleton is remarkable, in large partbecause of its completeness. Usually, whenwhales die, their bones are scattered acrossthe sea floor, making them difficult to digup in one piece. The find isn’t the mostcomplete of Godfrey’s career. But it’sclose.

Volunteers at the museum havealready begun the painstaking process of“prepping” what’s left of it. Using paint

brushes and dental scalers, they willslowly dust and scrape the mud and clayaway from the animal’s skull, leaving onlythe coffee-colored fossil behind.

As the skull emerges from the muck,Godfrey’s work will begin. “As we prepthe skull, the initial task will be [to ask]what kind of whale will it be,” he says.“It’s probably a known form, but we don’tknow that for sure. There’s a slim chancethat this is a new kind of extinct whale.”

Even without a name, Godfrey canstill glean valuable information abouthow this animal might fit into the evolu-tion of whales. Based on where it wasfound in the cliffs, for instance, Godfrey’steam estimates that this specimen is about14 million years old. It was also a“baleen” whale, a group of animals thatexist today and include blue, humpback,and gray whales.

These creatures are known for takinga diverse approach to eating, Godfrey says.Some, like blue and minke whales, feedby way of their gaping mouths. As theyswim, they open up, capturing schools ofkrill and other small organisms. Graywhales, on the other hand, go for crea-

tures living in the mud. Using their toughheads, they rake the ocean bottom, slurp-ing up a host of burrowing organisms.

Based on the anatomy of its skull,however, the Virginia whale doesn’t seemto fit cleanly into either category, Godfreysays. He suspects that this animal mayrepresent a mid-way point in the evolu-tion of whale dining. The members ofthis species were “a little bit like graywhales, but they were heading towardwhat blue whales were doing,” he says.

For a paleontologist with a deep loveof evolution, knowing how ancient ani-mals lived is a big part of the fun.

“If you can describe a fossil, name it,that’s fun. But if you can tell more of thestory, that’s kind of the bonus,” Godfreysays. “Who doesn’t like a good story?”

A Nose for Whales Right now, there’s a whole story laid outaround his office. This one has to do witha less well-known piece of the evolutionof whales — how some lost their abilityto smell.

To tell that story, Godfrey points to aseries of animal skulls around his office.


Some of the skulls are from fossil animals,but others came from modern ones.There’s a cow skull, one from a moose,and another from a modern bottlenosedolphin.

Godfrey picks up one of the items.This skull, taken from a deer, has beensliced right behind where the creature’snostrils would have been. The cut lets youlook back into the animal’s nasal passages.“You can see the turbinates,” Godfreysays, poking his ballpoint pen into thedeer’s nose, “very thin, scroll-like bones.”

And, indeed, jammed behind the nose,there’s a collection of twirling bones.End-on, they look a bit like old parch-ments stacked on a shelf. These fragile-looking structures were critical to thedeer’s sense of smell, Godfrey says. Afterinhaling, odors would have pooled aroundthese bones, allowing the animal to pickup the smells.

You might not think that whales,which spend most of their lives underwa-ter, can smell at all. But some livingwhales, Godfrey notes, have similar struc-tures inside their own nasal passages. Thatindicates that they can also smell the salty

sea air. In particular, it’s the baleen whales,like the species collected from Virginia,that seem to be able to take a good sniff.

But another group, called toothedwhales, can’t smell. They don’t need to.Unlike baleen whales, these mammals,which include dolphins, sperm whales,and narwhals, hunt fish and squid usingthe equivalent of sonar — they listen tohow noises bounce around in the envi-ronment. That trait, shared by bats, iscalled echolocation.

To explore when toothed whales losttheir ability to smell, Godfrey came upwith a new technique for using a CTscanner to measure various structures inthe skulls of fossil whales. To start off, heexamined the skull of a roughly 16-mil-lion-year-old toothed whale — called aSqualodon — that had been found high upin Calvert Cliffs. The creature, it turnsout, still had the remnants of turbinatesburied in its nasal passages, Godfrey says.And that suggests that it, too, could takein aromas.

By the time bottlenose dolphinsemerged around the globe in relativelymodern times, however, those structures

had disappearedentirely. “In theMiocene, we actuallysee the loss of thesense of smell intoothed whales,” hesays.

Baleen whales, onthe other hand,never lost their abil-ity to smell, Godfreysays. In fact, accord-ing to his research,the structuresinvolved in theirsense of smellremained largelyunchanged over tensof millions of yearsof evolution. Thefact that these whaleshung onto theirsmell structures forso long suggests thatthey needed that

anatomy to survive, Godfrey says. Andthey’re likely still putting their sense ofsmell to good use today.

Scientists working with modernwhales have reasoned that these animalsmay be using their noses to follow schoolsof krill and other organisms. These stinkycrustaceans are known to give off a slightodor — it is part of the smell that mostpeople associate with the ocean, saysGodfrey. “Just like a wild animal, a rac-coon, opossum, a dog, can follow ascent. . . baleen whales seem to be doingthe same thing,” he says.

The paleontologist and his colleaguespublished their findings on whale smell intwo papers in 2013 in the journals TheAnatomical Record and Comptes RendusPalevol.

Olivier Lambert, the Belgian paleon-tologist, notes that scientists had longknown about the diverging senses of smellin baleen and toothed whales, “but whatStephen did is he tried to quantify this,”he says. “And this is a nice advance in thefield.”

Growing a Backbone

Back on the beach in Virginia, Godfrey isalmost done extracting the whale verte-bra. Stowed in its plaster “field jacket,” thefind should be safe to move now. Givinga grunt, the paleontologist rolls it out ofits hole, all in one piece.

Godfrey’s day of digging may be over,but he knows that paleontology aroundthe Chesapeake’s cliffs will continue fordecades. Long after Godfrey is retired,researchers will continue to improve thepicture of how animals like whalesevolved during this one period in prehis-tory, fossil by fossil. “If we keep findingnew stuff, keep finding new fossils,” hesays, “then we have a much better chanceof . . . moving paleontology forward anddescribing in greater detail the diversityof animals that were here before us.”

On his way out, the paleontologisthoists the heavy fossil into his knapsack,then heads down the beach, carrying iton his own back — one more small pieceof a much, much bigger story.



A collector’s dream, the Chesapeake’s eroding cliffs have unearthed avariety of ancient species, as these examples show. What looks like atrough of dirt (opposite page, top) is actually a “field jacket” containing afossilized whale skull found earlier this year in Stratford Cliffs. Curatorsare slowly cleaning the skull. Other species include a crocodile (oppositepage, bottom left) and a now-extinct long-snouted dolphin (above). Nocreature has captured the imagination of non-scientists quite so much asthe megalodon, a hulking shark that could grow up to about 60 feet long.Lucky fossil hunters can still find the shark’s teeth (opposite page, bottomright). On the small end of the scale is the sea snail belonging to thegenus Ecphora (opposite page, bottom middle). PHO TO GRAPHS CO URTESY O F

STEPHEN GO DFREY, CALVERT MARINE MUSEUM


T housands of yearsago, naturalprocesses began to

form Calvert Cliffs, whichloom over the ChesapeakeBay as a natural and scien-tific marvel.

Erosion was the chiefengineer that built thesecliffs. Over millennia, windand waves steadily weath-ered away the Bay’s westernshore, exposing the tower-ing structures, among thetallest cliffs along the Mid-Atlantic. Those processescontinue today, presentingrewards and risks, depend-ing on your point of view.

Scientists are drawn tothese rock faces, whichextend along some 30 milesof shoreline in CalvertCounty, Maryland, because that sameerosion has helped to expose a panoplyof fossils. They include the remains ofancient whales and other sea creatures.Such discoveries have helped researchersbetter understand the evolution ofmarine organisms worldwide (see TheChesapeake’s Excellent Fossils, p. 8).

But for those who have chosen to buyhomes along the cliffs’ top, erosion hasbeen a mixed blessing. Yes, it created the100-foot walls where residents can lookout over the Bay and the ships passing by.But erosion has also caused the edge ofthese cliffs to recede toward nearbyhouses, by up to three feet a year in someplaces. Many homes are now at risk oftumbling down to the beaches below.

Some residents who live near thesteep cliffs have worked for decades to

slow the steady collapse that threatenstheir homes. These efforts, however, canhave unintended consequences. In thiscase, humans risk permanently alteringthe appearance of the cliffs, a local land-mark, and may make them useless as ascientific resource. As homeowners livingelsewhere beside the Bay have discovered,controlling erosion can be a challengethat has no easy solutions.

The Classroom

Peter Vogt, a geologist, places a highvalue on Calvert Cliffs as a teachingtool. He lives in Scientists’ Cliffs, a rusticcommunity about midway along thechain of outcrops. He thinks of thebeach below his home as a classroom.Vogt often guides field trips from localschools to the beach so that students can

get a firsthand look at theregion’s special geology andfossil specimens .

On a windy day, the sci-entist takes a walk down thesandy strip to show off thelocal geology. He reaches abare patch of cliff face,which he calls his black-board. Like a math teacherstanding in front of a chalk-board filled with equations,Vogt points to interestingevents in the planet’s historythat have been recorded inthis gray surface. “It’s likeour local equivalent of theGrand Canyon,” says Vogt,who retired years ago fromthe U.S. Naval ResearchLaboratory near ChesapeakeBeach.

And like that nationallandmark, these cliffs owe their existenceto erosion. Millions of years ago, the sedi-ment contained in the outcrops made upan ancient sea floor. Then, as ages passed,sea levels rose and fell over and over againaround the area where the Chesapeakenow sits — driven by a series of ice agesand warmer periods that occurred acrossthe globe. As waters curved around whatis now known as Maryland’s westernshore, they slowly carved away at theancient sediments there. Eventually, thesteep cliffs that you see today wereformed.

Or as Vogt puts it, spectacular geologyand erosion often go hand in hand. “Mostof our national monuments are due toerosion,” he says.

Erosion can occur along the cliffs fora number of reasons, he explains. Water

Efforts to control erosion may threaten unique geologyDaniel Strain

SAVING CALVERT CLIFFS

On the beach below his home in Scientists’ Cliffs, retired geologist Peter Vogtpoints to his “blackboard.” He removed the moss and ivy from this bare patch ofcliff face the day before to prepare for a school group that he’s leading to explorethe local geology. Erosion-control efforts could slow the retreat of the cliffs but alsoblock access to these unique formations. PHO TO GRAPH, DANIEL STRA IN

lapping at the base of the cliffs under-mines the outcrops, causing them to col-lapse. And as ice freezes and thaws on thecliff face, it also weakens the features. Thismelting causes soft, moisture-rich chunksof sediment to slip off the cliff face andslide down to the beach.

Over long time periods, the cliffs byVogt’s house recede by less than a foot ofland per year on average, according torough estimates reported by the MarylandDepartment of Natural Resources CoastalAtlas program. Elsewhere, the cliffs canrecede much faster. At spots north ofCove Point toward the south end of thecounty, for instance, Calvert Cliffs arepushed back annually by nearly threefeet on average.

That high rate of erosion — muchfaster than what you would see byrocky cliffs — hinges on the sedimenttrapped in the cliffs: many portions ofthe cliff chain are made up ofloosely bound sands, silts, andclays. For waves in the Bay, that’slike cutting through butter.

Vogt’s home sits about250 yards from the cliffs’edge, so he doesn’t have toworry much about thaterosion. But many of hisneighbors aren’t so lucky.

Gary Loew is anotherhomeowner in Scientists’Cliffs who is very familiarwith this erosion. Recentlyretired from an administra-tive position at the U.S.Army Corps of Engineers,Loew grew up in Scientists’Cliffs in the 1950s and 60s.The community was founded in 1935and today encompasses nearly 250 homesowned by a mix of retirees, professionals,and seasonal residents.

When Loew was a child, only a nar-row strip of front yard separated his par-ents’ house from the cliff face — and asteep drop. Today, there’s nothing left ofthat waterfront cabin.

That is because in 2011, the CalvertCounty government applied for a grantthrough the Federal Emergency

Management Agency to buy 10 privatelyowned homes along the cliffs. Thehouses, located at the edge of the out-crops, were in imminent danger of beinglost to erosion. And two of them, includ-ing the old Loew house, were part ofScientists’ Cliffs. All but one of the 10homes have since been demolished.

“It was very sad,” Loew says. “I mean,

it was not only my childhood home. Myfather built it.”

In order to prevent such losses, theCalvert County government adoptedregulations in the 1980s to limit develop-ment near to the cliffs’ edge. But plentyof homes were built before and remainstanding today. As of 2011, more than 230houses sat within 100 feet of the cliffs’edge, according to data kept by theCalvert County government. Roughlyone-third of those were within 20 feet.

“If you can see the sea, then the seacan see you,” says Kenneth Rasmussen, ageologist at the Northern VirginiaCommunity College who lives a shortwalk away from Brownie’s Beach at thenorth end of the cliff chain. “And it’sgoing to get you eventually.”

Slowing the Inevitable

On his walk, Vogt points out a remedythat may help homeowners to get aheadof the sea — if only for a little while.

By one stretch of beach, the cliff faceis covered at its base with a line of meshcages filled with heavy rocks. The cagesare stacked on top of each other, addingup to about three feet high. Called

gabions, these contraptions stretch downthe cliffs for more than 100 feet. Theycompletely block from view the

cliffs’ oldest and arguably mostinteresting layers, Vogt says.“They’re destroying my black-

board,” he says.This small stretch of

gabions is just the begin-ning. Over the next several

years, residents ofScientists’ Cliffs plan toput in around 1,600 feetof gabions up anddown the beacheshere. In all, the projectwill cost the commu-nity around $40 to$45 per linear foot ofgabions installed,estimates NormanPrince, a local home-owner who chairs theBeach and Cliffs

Committee for the residents of Scientists’Cliffs.

But for him and many of his neigh-bors, the gabions will be worth it: thesestructures — which perform a similarrole to rip-rap, or large boulders that havebeen stacked on top of each other —should protect the cliffs from waves. And,engineers say, that should help to slowerosion.

Such ventures aren’t unheard oflocally: most of the length of Calvert


Cliff Collapse(no erosion control)

Cliff Stabilization and Slope Formation(with erosion control)

wave action undercuts cliff base

gabion wall protects cliff base

cliff top continues to erode

cliff maintains a steep angle of about 70°, causing rapid erosion

with protection, cliff is stabilized as a more gradual slope with an angle in the 25-37° range, slowing erosion

cliff collapses as its base erodes

erosion debris accumulates

Erosion can get you in two ways on Calvert Cliffs, scientists have shown.Naturally eroding cliffs maintain a steep slope as they recede. Cliffs protected byerosion-stabilization efforts — like gabions — ideally, recede more slowly, becominggentle slopes. Either way, houses that are too close to the edge may come tumblingdown . ILLUSTRAT IO NS, ADAPTED BY SANDY RO DGERS FRO M FIGURES IN CLARK ET AL. 2004

Cliffs falls inside privately-ownedland. A large cliffside developmentto the south of Scientists’ Cliffs,called Chesapeake Ranch Estates,for instance, also recently obtainedpermits to similarly protect its cliffs.

Vogt, however, contends thatefforts like these merely trade oneproblem for another. Erosion maybe a hazard for homeowners, butit’s also the key to Calvert Cliffs, hesays. When the cliffs are allowed toerode naturally, as they have donefor millennia, they recede. And as theyrecede, they retain the steep, vertical dropthat the features are known for. It’s a bitlike cutting a piece out of a cake.

But when humans slow that erosionfrom happening, the cliffs don’t stay cake-like: the base of the cliffs remains stable,but the top continues to crumble away.Before long, what was once a steep cliffbecomes a gently curving hill that is sooncovered in moss, ivy, and, eventually, trees.

The consequences of that transforma-tion for scientists like Vogt would be dire:as the cliffs form into hills, the features’geologic strata — his teaching surfaces —would become buried under layers ofdirt, making them all but invisible.Without erosion, the supply of fossils thatpaleontologists also love so much wouldbe effectively cut off, too.

A 2004 report by a research team ledby the U.S. Geological Survey concluded

that Calvert Cliffs could be transformedthis way in 35 to 40 years or even lessfollowing the installation of structureslike gabions.

That seems to leave the Bay’s cliffdwellers with a difficult choice: lose thecliffs or lose your homes. Vogt isn’t theonly scientist who has argued for savingthe cliffs.

“If Calvert Cliffs are unique, which Itruly believe they are, why do we want todestroy that uniqueness?” asks RalphEshelman, a paleontologist who served asthe founding director for the CalvertMarine Museum in Solomons. “Why dowe want the shores of the ChesapeakeBay to look like the shores along the restof the East Coast?”

Living with Erosion

In the end, erosion will eventually swal-low some homes on Calvert Cliffs no

matter what steps are taken tocontrol it, scientists say. Whetherthe cliffs collapse from below orerode from the top and formslopes, houses close to the edgewill still be undermined.Homeowners , in other words,can’t escape the Bay forever.

It’s a reality that the residentsof Scientists’ Cliffs are aware of,says Norman Prince. “We’re notdoing this with the idea that weare going to preserve in perpetu-

ity the houses that are presently on thecliff face,” he says. “We are doing this toslow the process down.”

Despite the risk, Gary Loew, whosaw his old family home lost to erosion,wanted to spend his retirement there.He and his wife purchased a house abouta year ago around 50 feet from the cliffedge. Loew says they did so because theylove the community . They’ve formedtight bonds with their neighbors , anderosion or no, the view is a beauty.

He also thinks that he will haveenough time to get the most out ofhis home before the eroding cliff facedraws too close. “It’s a calculated risk,”he says. “I’m retired. I’m older. I figurewe’ve got 10 or 15 years in this housebefore we have to downsize, so I thinkI’m good.”


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A long line of gabions (metal cages containing large rocks) wasinstalled in fall 2013 to protect this cliff base in Scientists’ Cliffs.Erosion along the length of the cliffs threatens to overtake severalhomes, dumping them into the surf. PHO TO GRAPHS: LEFT , DANIEL STRA IN;

RIGHT , DAV ID BRO WNLEE

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