Story and Photos by Chris Linder
When winter winds began rattling the storm windows last autumn, Andrey Shcherbina and Glen Gawarkiewicz shook the mothballs out of their cold-weather exposure suits and dusted off their sea boots. For the second consecutive winter, the two physical oceanographers at Woods Hole Oceanographic Institution (WHOI) and their small team braved rowdy seas to study how winter storms affect the shallow current flowing south through our coastal back yard—parallel to Cape Cod’s extended forearm, from Provincetown to Chatham.
Andrey and Glen aren’t the only ones interested in how the coastal current changes in winter. Ted Ligenza, a Chatham hook fisherman, also wants to know. The cod he chases with his longlines have an affinity for well-mixed winter water. Ted monitored the results of our experiment last winter—in particular, how offshore water temperatures changed from surface to seafloor—by watching our project’s website. Shellfish farmers and state health officials are also keenly interested, because the coastal current controls the movement of dangerous red tide algae around the Cape.
Like the atmosphere with its ever-moving high- and low-pressure systems, the oceans have the equivalent of “undersea weather.” The oceans have masses of relatively colder or saltier water that are denser and sink, or warmer or fresher waters that are more buoyant and rise. These masses continually move and interact to produce a highly energetic environment. Many factors influence the undersea weather. Cold winter air cools the sea surface; precipitation adds fresh water; tides and winds mix things up. Winter storms may do all three, but not many scientists have measured it directly because winter oceanography can be both difficult and costly, involving large ships, long cruises, and big fuel bills.
Our mission is to reveal how the Outer Cape water masses’ temperature, salinity, and currents change during the winter. Funded by the WHOI Coastal Ocean Institute and the Woods Hole Sea Grant program, we used a combination of inexpensive, lightweight moored instruments and a sophisticated autonomous swimming vehicle called the REMUS (Remote Environmental Monitoring UnitS). Both were deployed from small, fast boats—when the weather allowed.
Oct. 10, 2005A
blustery late October morning finds Andrey Shcherbina, Glen
Gawarkiewicz, and me at an empty boat landing in Eastham. We’re waiting
for Dawson Farber, the harbormaster. He’s going to be taking us out in
his boat for a REMUS mission.
Problem is, there are no boats in
the water. He arrives right on time with his smaller-than-expected
skiff on a trailer. He’s a tall guy, built like a Navy SEAL, wearing a
big orange-and-black mustang suit. “Brought your foul-weather gear I
hope!” he grins as he loads gear into the tiny open cockpit boat.
take a look at the skydark clouds on the horizon are promising some
fun. We suit up and launch the boat. Andrey programs the mission into
the REMUS as we glide through the calm waters of Nauset Harbor.
Oct. 10, 2005At
the shallow break separating bay from open ocean, we hit a wall of
heavy swell. After a few minutes of bouncing on the waves, we arrive at
the deployment site. We quickly lower the REMUS over the side and send
the start signal. Off it goes on its predetermined route eastward,
undulating from the surface down to 90 meters (300 feet) to capture a
cross-section of temperature, salinity, and current speed and direction.
we follow the REMUS, the clouds turn a shade more menacing. Dawson
keeps checking his gas gauge and his watch, which makes me nervous.
Once the clouds start spitting their first raindrops, we send the abort
command. We grab the REMUS and beat back to safety with water sheeting
over the rails and a storm kicking up all around us.
to the skin when we pull back in to Eastham, but overall, it was a
great start to this winter’s worka nice late fall data section at a
fraction of the cost of a day aboard the research vessel Oceanus.
And, we’re back at WHOI in time to make the afternoon seminar.
|Dec. 19. 2005Mooring
deployment day finds me shoveling down cereal in the predawn darkness
at my house. I grab my thermos, pack up my bags, and drive down to the
pier. Today we’re in the hands of Ken Houtler (left), captain of WHOI’s
coastal research vessel Tioga, and crewman Ian Hanley. We load up the equipment by the glow of the Tioga’s
floodlights. A frosty wind tears at our faces, so I put on the
foul-weather "mustang" suit before we even leave the pier. We slip away
into black waves before 7 a.m. It’s a three-hour transit to our working
area east of Cape Cod. On the way there, I try to get some sleep
in one of the bunks but am getting serious air time with every wave we
hit. Not super relaxing.|
Dec. 19. 2005WHOI
Engineer Craig Marquette (hands), Andrey (left), Glen, Ian (right), and
I assemble the small moorings on the heaving fantail, pay them out the
back, and push them into the cold water. We tie-wrapped the tiny
temperature-measuring loggers on the lines at WHOI beforehand. Craig
says it best: “Now it’s all grunt work.” Attach float to mooring line.
Throw float over the side. Pay out line. Pay out chain. Push over the
I do most of the work on my knees so that I can
better maintain my balance. By 3 p.m., the sun is sinking low on the
horizon. All of the mooringssix lightweight temperature logger strings
and two bottom-mounted instrument cagesare safely at sea with no
mishaps; a very good day.
Everyone keeps asking where I got my tan. I think it’s actually windburn.
Dec. 21, 2005Winter
solstice, the shortest day of the year. It’s pitch black when we pull
into the parking lot and load the coffin-sized REMUS case onto Tioga.
The light from Nobska Lighthouse winks goodbye as we accelerate away
from Woods Hole. When we arrive at the mission’s start point, the
sun has just broken the horizon. Dripping seawater has frozen into
icicles on the anchor chain.
The REMUS collects data while we
hunker down out of the wind behind the pilot house. The sun is back
down before we hit the pier. We’re the science vampiresleaving in the
dark, returning in the dark, carrying a heavy coffin full of data
sucked from the sea.
|Jan. 20, 2006The
holidays have passed and with them a few more storms. We have returned
for more data to add to our picture of the evolving winter oceanography.|
a weather window for our work has been a challenge. We watch the
forecast, trying to guess how it will change before we arrive at the
pier. Waiting for acceptable conditionswinds at or below 15 knots and
seas under 6 feethas been frustrating. After a hurried meeting, Glen
makes the call: “Marginal is better than nothing, let’s go for it.” On
this particular January day, the light aluminum Tioga bobs corklike on the northeasterly swell.
I can see the exhaustion written on everyone’s faces. We deploy the
REMUS and turn on the acoustic tracking. Our routine is now familiar:
We take turns lowering the small fishlike tracking device into the
water, then we wait for the vehicle to send us its status. After
confirming the vehicle is on track, we pull the “fish” back onboard and
head off to the next location.
We’re battered and bruised from
trying (unsuccessfully) to keep our footing on the pitching deck. The
seasickness medication makes me a walking zombie. By midday, we’re all
catnapping on the transits, lulled by the throbbing bass of Tioga’s engines. Rainbowsprobably the last thing I’d expect to see on a day like thisform in the white water flying over the rail.
Feb. 21, 2006The
weather looks great in this photoclear blue skiesbut the mustang
suits tell the real story. The air is freezing and the cold water from
the wet mooring lines has soaked through my gloves. We can see
our breath when the wind isn’t ripping it out of our lungs. The
physical labor keeps our minds from seasickness.
winter two entire mooring chains were mysteriously lost, so it is a
relief when we find that all six of the temperature moorings are right
where we left them three months ago. Only two moorings, the
bottom-mounted cages, remain.
Feb. 21, 2006“OK,
one more time,” Craig signals to Andrey to lower the acoustic
transponder over the side. It sends a coded acoustic signal to the
bottom-mounted moorings with an Acoustical Doppler Current Profiler
(ADCP). The moorings are programmed to release a float attached to a
line. Then we haul the line and instruments aboard. The problem is, one
of the moorings isn’t answering. After circling the spot for an hour
with no communication from the mooring, we give up for the day.
Feb. 21, 2006Andrey
unclips the temperature loggers from the mooring lines while Ian pulls
them up with the winch. Only the uppermost loggers have been lost.
“Must have been some abrasion with the surface float,” Andrey
speculates as he unclips another logger.
Feb. 21, 2006Andrey
drops loggers full of data into a bucket. Each one of the precious
loggers holds a winter’s worth of data on water temperatures. We
thought we were suffering, but the moorings weathered some real storms
while we were back in the office.
March 24, 2006Andrey
is on the phone with Greg Packard, REMUS expert from the WHOI Applied
Ocean Physics and Engineering Department, getting some technical advice
at sea. Glen (center) and Jen Hua Tai, a visiting student from Taiwan
(blue jacket) watch expectantly to see if data from a sidescan sonar
will reveal the location of the missing ADCP mooring. “Wave ripples,
sandy bottom,” Andrey declares as he scans the images. Of the lost
mooring, there isn’t a trace.
March 24, 2006WHOI
Engineer Tito Collasius drives the controls on a remotely operated
vehicle, panning around with the vehicle's camera to look for the
missing mooring. Craig (left) watches the monitor. Jonathan Borden of
the U.S. Geological Survey is in the background.
current is too strong to anchor. I’ll have to keep her in position
using the engines,” Captain Ken Houtler explains. After a full day of
searching, we give up on the missing mooring. It’s possible that a
scallop trawler snagged it and dragged it far out to sea.
As I was typing the last caption for this article, Craig Marquette
received an unexpected phone call. It was Henrique Franco, the skipper
of the fishing vessel Mary K, calling to say that he had caught a large yellow object in his nets while fishing off Chatham on July 8. Once the Mary K
pulled into port, Andrey and I drove over to New Bedford to retrieve
our missing mooring. While only a portion of the data could be
recovered from the cod-scented instruments, it was still a relief to
get them back. This summer we will be piecing together the story of
winter beneath the waves and drying out the survival suits for next
Posted: July 27, 2006