Special Issue on the
Ocean Observatories Initiative
Oceanography
THE OFFICIAL MAGAZINE OF THE OCEANOGRAPHY SOCIETY
VOL.31, NO.1, MARCH 2018
VOL. 31, NO. 1, MARCH 2018
Ian Walsh, Ph.D., Director of Science
Nutrient and Estuarine Processes Driven by Hurricane Irma Recorded by
the Indian River Lagoon Observatory Network of Environmental Sensors
Friday, February 16, 2018; 3:36-3:48 PM, Oregon Convention Center, F151
Measuring Calibration and Field Variance Scales in Oceanographic
Optical Instrumentation Data for Quality Assurance
Tuesday, February 13, 2018; 4:00-6:00 PM, Oregon Convention Center, Poster Hall
Charles W. Branham, Ph.D., Senior Chemist
Field Validation of ISFET Based Ocean pH Sensors
Wednesday February 14, 2018; 4:00-6:00 PM, Oregon Convention Center, Poster Hall
Kim Martini, Ph.D., Senior Oceanographer
Dynamic Corrections for Sea-Bird Surface Temperature Salinity
Sensors (STS) on ARGO Profiling Floats
Monday, February 12, 2018; 4:00-6:00 PM, Oregon Convention Center, Poster Hall
David J. Murphy, MS, Director of Science
Determination of Conductivity Cell Compressibility for Argo
Program CTDs and MicroCATs
Tuesday, February 13, 2018; 4:00-6:00 PM, Oregon Convention Center, Poster Hall
+1 425 643 9866 | seabird@seabird.com | seabird.com
Sea-Bird Scientific Presentations at the
2018 Ocean Sciences Meeting
See Us at Booth 113
Oceanography | March 2018
2.2
2.2
2.0
2.0
1.8
1.8
1.6
1.6
1.4
1.2
1.2
1.0
1.0
104
~10 times water depth
contents
VOL. 31, NO. 1, MARCH 2018
12
FROM THE GUEST EDITORS. Introduction to the Special Issue on
the Ocean Observatories Initiative
By L.M. Smith, T.J. Cowles, R.D. Vaillancourt, and S. Yelisetti
16
The Ocean Observatories Initiative
By L.M. Smith, J.A. Barth, D.S. Kelley, A. Plueddemann, I. Rodero, G.A. Ulses,
M.F. Vardaro, and R. Weller
36
Sidebar > Accessing OOI Data
By M.F. Vardaro and J. McDonnell
38
On the Relationship Between the Global Ocean Observing System and
the Ocean Observatories Initiative
By E. Lindstrom
42
The North Atlantic Biological Pump: Insights from the Ocean Observatories
Initiative Irminger Sea Array
By H.I. Palevsky and D.P. Nicholson
50
Deep Convection in the Irminger Sea Observed with a Dense Mooring Array
By M.F. de Jong, M. Oltmanns, J. Karstensen, and L. de Steur
60
The Changing Nature of Shelf-Break Exchange Revealed by the
OOI Pioneer Array
By G. Gawarkiewicz, R.E. Todd, W. Zhang, J. Partida, A. Gangopadhyay, M.-U.-H. Monim,
P. Fratantoni, A. Malek Mercer, and M. Dent
71
Sidebar > SeaView: Bringing Together an Ocean of Data
By K. Stocks, S. Diggs, C. Olson, A. Pham, R. Arko, A. Shepherd, and D. Kinkade
72
Atmospheric and Offshore Forcing of Temperature Variability at the
Shelf Break: Observations from the OOI Pioneer Array
By K. Chen, G. Gawarkiewicz, and A. Plueddemann
80
Temporal and Spatial Dynamics of Physical and Biological Properties
along the Endurance Array of the California Current Ecosystem
By F. Henderikx Freitas, G.S. Saldías, M. Goñi, R.K. Shearman, and A.E. White
90
Warm Blobs, Low-Oxygen Events, and an Eclipse: The Ocean Observatories
Initiative Endurance Array Captures Them All
By J.A. Barth, J.P. Fram, E.P. Dever, C.M. Risien, C.E. Wingard, R.W. Collier,
and T.D. Kearney
98
Power from Benthic Microbial Fuel Cells Drives Autonomous Sensors
and Acoustic Modems
By C.E. Reimers and M. Wolf
104 The Role of the Ocean Observatories Initiative in Monitoring the Offshore
Earthquake Activity of the Cascadia Subduction Zone
By A.M. Tréhu, W.S.D. Wilcock, R. Hilmo, P. Bodin, J. Connolly, E.C. Roland,
and J. Braunmiller
SPECIAL ISSUE ON
The Ocean Observatories Initiative
16
60
90
Oceanography | March 2018
Oceanography | Vol.31, No.1
CONTACT US
The Oceanography Society
1 Research Court, Suite 450
Rockville, MD 20850 USA
t: (1) 301-251-7708
f: (1) 301-251-7709
info@tos.org
HAVE YOU MOVED?
Send changes of address to info@tos.org
or go to https://tosmc.memberclicks.net,
click on Login, and update your profile.
ADVERTISING INFO
Please send advertising inquiries to
info@tos.org or go to https://tos.org/
oceanography/advertise.
CORRECTIONS
Please send corrections to magazine@tos.org.
Corrections will be printed in the next issue
of Oceanography.
SPECIAL ISSUE SPONSOR
Production of this issue of Oceanography
was supported by the Consortium for
Ocean Leadership through National Science
Foundation Cooperative Support Agreement
OCE-1026342.
SPECIAL ISSUE GUEST EDITORS
• LESLIE M. SMITH
Consortium for Ocean Leadership
• TIMOTHY J. COWLES
Oregon State University (emeritus)
• ROBERT D. VAILLANCOURT
Millersville University
• SUBBARAO YELISETTI
Texas A&M University-Kingsville
ON THE COVER
The Ocean Observatories Initiative (OOI) is a National Science Foundation
major research facility operated as a community resource, providing con-
tinuous delivery of ocean and seafloor data from the coast to the open
ocean in the Atlantic and the Pacific. The map shows the locations of the
seven OOI arrays (image credit: OOI Cabled Array program & the Center
for Environmental Visualization, University of Washington). Inset photos
show infrastructure from the Coastal, Global, and Cabled Arrays (clockwise
from top): deployment of a Pioneer Array Coastal Surface Mooring from
R/V Atlantis (credit: OOI Pioneer Array Program, WHOI); Irminger Sea
Global Surface Mooring waits on the deck of R/V Knorr for deployment
(credit: OOI Global Array Program, WHOI); Endurance Array Coastal
Surface Mooring components await deployment (credit: OOI Global Array
Program, OSU); digital still camera deployed on Axial Seamount captures
the El Gordo hydrothermal vent and attached OOI Cabled Array instru-
mentation (credit: NSF-OOI/UW/ISS; Dive R1839; V15).
114
114
The Recent Volcanic History of Axial Seamount: Geophysical
Insights into Past Eruption Dynamics with an Eye Toward Enhanced
Observations of Future Eruptions
By W.S.D. Wilcock, R.P. Dziak, M. Tolstoy, W.W. Chadwick Jr., S.L. Nooner,
D.R. Bohnenstiehl, J. Caplan-Auerbach, F. Waldhauser, A.F. Arnulf, C. Baillard,
T.-K. Lau, J.H. Haxel, Y.J. Tan, C. Garcia, S. Levy, and M.E. Mann
124 A Tale of Two Eruptions: How Data from Axial Seamount Led to
a Discovery on the East Pacific Rise
By M. Tolstoy, W.S.D. Wilcock, Y.J. Tan, and F. Waldhauser
127 Sidebar > Axial Seamount Biology Catalog
By K. Bigham
128 Deep-Sea Volcanic Eruptions Create Unique Chemical and
Biological Linkages Between the Subsurface Lithosphere and the
Oceanic Hydrosphere
By R.L. Spietz, D.A. Butterfield, N.J. Buck, B.I. Larson, W.W. Chadwick Jr., S.L. Walker,
D.S. Kelley, and R.M. Morris
136 Sidebar > Get Engaged with the Ocean Observatories Initiative
By G.A. Ulses, L.M. Smith, and T.J. Cowles
138 Education and Public Engagement in OOI: Lessons Learned
from the Field
By J. McDonnell, A. deCharon, C.S. Lichtenwalner, K. Hunter-Thomson, C. Halversen,
O. Schofield, S. Glenn, C. Ferraro, C. Lauter, and J. Hewlett
147 Sidebar > Seastate: Experiential C-STEM Learning Through Environmental
Sensor Building
By D.S. Kelley and D. Grünbaum
DEPARTMENTS
05
QUARTERDECK. The Squirrelly Thing About Knowledge
By E.S. Kappel
07
FROM THE PRESIDENT. On Mentoring of Graduate Students
By A.C. Mix
08
RIPPLE MARKS. Icon of Chesapeake Winter Still Graces the Bay
By C.L. Dybas
148 THE OCEANOGRAPHY CLASSROOM. Are You a Marine Major or Minor?
By S. Boxall
150 CAREER PROFILES. Heather Havens, Vice President, Program Develop-
ment, National Defense Industrial Association • Andreas Krupke,
Scientist III, Verification & Validation Department, Thermo Fisher Scientific
Oceanography | Vol.31, No.1
Oceanography | March 2018
EDITOR
Ellen S. Kappel
Geosciences Professional Services Inc.
5610 Gloster Road
Bethesda, MD 20816 USA
t: (1) 301-229-2709
ekappel@geo-prose.com
ASSISTANT EDITOR
Vicky Cullen
PO Box 687
West Falmouth, MA 02574 USA
t: (1) 508-548-1027
vcullen@whoi.edu
CONTRIBUTING WRITER
Cheryl Lyn Dybas
cheryl.lyn.dybas@gmail.com
DESIGN/PRODUCTION
Johanna Adams
johanna-adams@cox.net
Oceanography
https://tos.org/oceanography
Oceanography contains peer-reviewed articles that chronicle all aspects of
ocean science and its applications. The journal presents significant research,
noteworthy achievements, exciting new technology, and articles that address
public policy and education and how they are affected by science and technol-
ogy. The overall goal of Oceanography is cross-disciplinary communication in
the ocean sciences.
Oceanography (ISSN 1042-8275) is published by The Oceanography
Society, 1 Research Court, Suite 450, Rockville, MD 20850 USA. ©2018 The
Oceanography Society Inc. All rights reserved. Permission is granted for indi-
viduals to copy articles from this magazine for personal use in teaching and
research, and to use figures, tables, and short quotes from the magazine for
republication in scientific books and journals. There is no charge for any of
these uses, but the material must be cited appropriately.
Republication, systemic reproduction, or collective redistribution of any mate-
rial in Oceanography is permitted only with the approval of The Oceanography
Society. Please contact Jennifer Ramarui at info@tos.org.
ASSOCIATE EDITORS
Margaret L. (Peggy) Delaney
University of California, Santa Cruz
delaney@ucsc.edu
Charles H. Greene
Cornell University
chg2@cornell.edu
Kiyoshi Suyehiro
Yokohama Institute for Earth
Sciences, JAMSTEC
suyehiro@jamstec.go.jp
Peter Wadhams
University of Cambridge
p.wadhams@damtp.cam.ac.uk
The Oceanography Society was founded in 1988
to advance oceanographic research, technology,
and education, and to disseminate knowledge of
oceanography and its application through research
and education. TOS promotes the broad under-
standing of oceanography, facilitates consensus
building across all the disciplines of the field, and
informs the public about ocean research, innova-
tive technology, and educational opportunities
throughout the spectrum of oceanographic inquiry.
OFFICERS
PRESIDENT: Alan Mix
PRESIDENT-ELECT: Martin Visbeck
PAST-PRESIDENT: Susan Lozier
SECRETARY: Susan Cook
TREASURER: Susan Banahan
COUNCILLORS
AT-LARGE: Dennis McGillicuddy
APPLIED TECHNOLOGY: James Girton
BIOLOGICAL OCEANOGRAPHY: Charles H. Greene
CHEMICAL OCEANOGRAPHY: Peter Sedwick
EDUCATION: Carolyn Scheurle
GEOLOGY AND GEOPHYSICS: Richard Murray
PHYSICAL OCEANOGRAPHY: Magdalena Andres
STUDENT REPRESENTATIVE: Stefanie Mack
EXECUTIVE DIRECTOR
Jennifer Ramarui
CORPORATE AND INSTITUTIONAL
MEMBERS
BAKER DONELSON
» https://www.bakerdonelson.com
SEA-BIRD SCIENTIFIC
» https://sea-birdscientific.com
TELEDYNE RD INSTRUMENTS
» http://www.teledynemarine.com/rdi
CONTACT INFO
The Oceanography Society
1 Research Court, Suite 450
Rockville, MD 20850 USA
t: (1) 301-251-7708
f: (1) 301-251-7709
email: info@tos.org
https://tos.org
tos.org
Oceanography | March 2018
Oceanography | Vol.31, No.1
tos.org
https://tos.org/career-profiles
Check Out Our Career Profiles Page!
Do you have suggestions
on who to profile?
Please send their
contact information to
ekappel@geo-prose.com.
Self-nominations
are accepted.
In each issue, Oceanography magazine publishes “career profiles” of marine
scientists who have pursued successful and fulfilling careers outside of aca-
demia. These profiles are intended to advise ocean sciences graduate stu-
dents about career options other than teaching and/or research in a univer-
sity setting. They also include wisdom on how to go about the job search.
We have over 50 profiles of ocean scientists on our web page.
Check them out!
Visit The Oceanography Classroom
https://tos.org/classroom
Oceanography’s education columnists share their wisdom and insight in
The Oceanography Classroom each issue. Go to https://tos.org/classroom
where you can find all published columns.
Looking for Insight
on education?
Interested in Undergraduate
and Graduate Education?
Check out Oceanography’s Hands-On
Oceanography page https://tos.org/
hands-on-oceanography that contains
peer-reviewed activities that will help you
teach fundamental oceanography concepts
in undergraduate and graduate classrooms.
Hands-On
Oceanography
https://tos.org/
hands-on-oceanography
Oceanography | March 2018
On this gray winter day, I look out my family room window at the suet
feeder I just filled. Although I set this wintertime feeder out for the birds—
and even make my own suet (please contact me if you’d like the recipe)—I
know that the main beneficiaries of the food are the squirrels. With that
knowledge, I devise my own pitiful defenses against these clever and dex-
terous rodents, using twist-ties to prevent the squirrels from opening the
feeder, and slathering hot-pepper-infused shortening on the line from
which the feeder hangs to provide a lasting mouthful of fire. In the end, the
birds and I are the losers. The squirrels always prevail.
Watching the birds and squirrels leads to thoughts about observation
and experimentation. Those tools are the basis of conducting science, but
non-scientists use those same skills in solving everyday problems at work
and at home. A driver looks at the fuel gauge that is near empty and calcu-
lates whether she can make it to the next gas station. A shopper compares
prices and features on a new refrigerator to decide which one to purchase.
A vacationer checks the weather at his destination to know what clothes
to pack. A cook finds substitutes for missing ingredients when preparing a
recipe. A homeowner investigates the source of a leak when she sees a stain
on the ceiling. And yet, the same people who solve problems every day in
their work and home lives somehow reject the results of the same process of
observation and experimentation when those results are generated by uni-
versities, government agencies, and other components of Big Science. Why?
One of the great challenges of our time is educating the public that they
are scientists and mathematicians and engineers each and every day, and
that academic and government scientists aren’t strange people who pos-
sess some set of magical skills and work in secret laboratories. Along with
that understanding may come less fear and more appreciation of science
and less resistance to policy solutions that may involve short-term sacri-
fice for the sake of the long-term health of our planet. If people saw them-
selves as problem solvers, and saw scientists as fellow citizens who are just
trying to determine, on a larger scale, whether the fuel gauge is nearing
empty, we might be able to tackle pressing social and environmental issues
in a more congenial manner. Perhaps we can start by together solving that
knotty problem of keeping squirrels away from bird feeders, and then con-
tinue our collaborations on thornier issues.
Ellen S. Kappel, Editor
QUARTERDECK
The
Squirrelly
Thing
About
Knowledge
June 2018
Ocean Warming
September 2018 — Double Issue
1. Mathematical Aspects of Physical
Oceanography
2. Gulf of San Jorge, Patagonia, Argentina
December 2018
Scientific Ocean Drilling:
Looking to the Future (tentative)
In addition to the special issues articles,
Oceanography solicits and publishes:
• Peer-reviewed articles that chronicle
all aspects of ocean science and its
applications
• News and information, meeting reports,
hands-on laboratory exercises, career
profiles, and book reviews
• Editor-reviewed articles that address
public policy and education and how they
are affected by science and technology
• Breaking Waves articles that describe
novel approaches to multidisciplinary
problems in ocean science
Special Issues
Call for Submissions
https://tos.org/oceanography
Oceanography
UPCOMING IN
Oceanography | Vol.31, No.1
The origins of The Oceanography Society are rooted in
bringing together and recognizing individuals from all
fields of oceanography, representing the broad interests
of members in research, engineering, industry, policy, and
education, and the diversity and international nature of the
society. TOS members from all areas of oceanography will
be considered for the Fellows Program. A recommenda-
tion for advancement to TOS Fellow is appropriate after an
individual has been a TOS member for at least three years,
depending on his or her contributions to the field.
The main criteria for being elected a TOS Fellow are out-
standing and sustained contributions, and devotion to
the broad field of oceanography, commensurate with the
founding principles of the Society.
Nominations Deadline » October 31, 2018
Learn More » https://tos.org/tos-fellows
Recognizing Individuals Who Have Attained Eminence in Oceanography Through
Their Outstanding Contributions to the Field of Oceanography or Its Applications
CALL FOR NOMINATIONS
tos.org
TOS Fellows Program https://tos.org/tos-fellows
Help TOS Fulfill Its Mission!
Recognizing excellence, disseminating knowledge,
promoting communication
The Oceanography Society welcomes financial contributions of any size to
help support the Society’s mission of disseminating knowledge of ocean-
ography and its application through research and education, promoting
communication among oceanographers, and providing a constituency for
consensus-building across all the disciplines of the field. Contributions are
welcome in one or more of the following areas:
• COSTARS: Career Opportunity/Student Travel and Research
Support – Supporting travel for graduate students to conferences and
other institutions and organizations
• Student Fund – Supporting programs such as the TOS Mentoring
Program
• Early Career Fund – Supporting participation in career-enhancing
activities
• TOS General Fund – Used for greatest needs, as recommended by the
TOS Council
To contribute go to https://tos.networkforgood.com
tos.org
Oceanography | March 2018
Last year, The Oceanography Society started a mentoring pro-
gram to provide guidance to graduate students on how to
survive graduate school and find a satisfying career path-
way. Academic “elders” paired with co-mentors from indus-
try and government conduct monthly teleconferences with
small groups of students. Susan Lozier initiated this TOS pro-
gram following her term as president, building on her experi-
ence with the Mentoring Physical Oceanography Women to
Increase Retention (MPOWIR) program (http://mpowir.org),
which addresses some of the “leaky pipeline” issues for women
in physical oceanography. (You can read more about MPOWIR
and its positive impact on the field as a whole in previous issues
of Oceanography, e.g., Lozier 2005, 2009; Coles et al., 2011;
Clem et al., 2014.)
Using MPOWIR as model, TOS began its own prototype pro-
gram with two mixed-gender mentoring groups whose mem-
bers span all the fields of ocean science and technology and are
drawn from a wide range of universities across the United States.
In the future, we hope to expand the program internationally.
By combining participants from many institutions, we hope to
foster networks of young scientists who will build the future
of ocean sciences. As one of the participating members, here I
share some early results of this experiment.
The initial premise of the TOS program is that the mentors
will provide sage advice to the graduate students about career
pathways, among other topics. Certainly, we’ve done some of
that. We have had some interesting discussions about network-
ing, and have read some practical guidebooks on productive
networking. We’ve talked a bit about writing and speaking and
how to use storytelling techniques to get a message across. We’ve
addressed time management, and of course we’ve talked about
concerns regarding finding satisfying employment after gradu-
ate school. But it is also true that the students are mentoring the
mentors, teaching us about what they need. It is far too easy for
academic faculty to forget what it was like to be a graduate stu-
dent, but hearing the students’ concerns is enlightening. While a
graduate school experience can be good if an advisor is patient,
fair, thoughtful, and responsive to students, not every advisor
provides students with the training necessary for future success
as a faculty member, such as how to deal with graduate students
or how to teach effectively.
Some universities now have mentoring programs, but cer-
tainly not all. I recently reviewed the web pages of most of the
oceanographic programs in the United States and a few abroad,
and found several programs that have senior faculty serve as
mentors for junior faculty. These programs are a great start, but
these same pages offer relatively little about best practices in
mentoring graduate students, or training the students to become
future mentors. Despite promotion and tenure dossiers that
require applicants to write about their philosophy of education
related to teaching and mentoring, these web pages lack any state-
ments about institutional philosophies or practices. This is odd.
There is no single way to be a good mentor—we all have
unique strengths and personalities that we bring to the task—
but some attention paid to this most important (most joyful,
most frustrating, and most rewarding) faculty task will go a
long way toward improving our programs. For faculty members
who might like to start exploring some of these general mento-
ring issues, I recommend the MPOWIR Handbook (Clem et al.,
2016). Within TOS, we plan to build on our prototype program.
Over the next few years, we anticipate producing some gen-
eral materials on best practices in mentoring of graduate stu-
dents. I hope that our institutions will use, adapt, or build on
these guidelines. As we develop TOS guidelines for mentoring in
ocean sciences, I welcome input from faculty members and pro-
grams that have addressed mentoring issues. Perhaps a start in
shining a light on mentoring would be for TOS to initiate some
mechanisms to reward high-quality mentoring; my own institu-
tion has a student-administered award for mentoring that is one
of the highest honors a faculty member can receive.
For me, participating in the TOS mentoring program is reas-
suring in that it reinforces my view that the future of ocean sci-
ences will be in great hands as the young generation of students
and early career scientists steps up and takes the reins. I look for-
ward to learning more as the TOS program continues.
Alan C. Mix, TOS President
REFERENCES
Clem, S., S. Legg, S. Lozier, and C. Mouw. 2014. The impact of MPOWIR:
A decade of investing in mentoring women in physical oceanography.
Oceanography 27(4) supplement:39–48, https://doi.org/10.5670/oceanog.
2014.113.
Clem, S., C. Mouw, and S. Legg. 2016. MPOWIR Handbook. Available at:
http://mpowir.org/wp-content/uploads/2017/01/MPOWIR-Handbook.pdf.
Coles, V., L. Gerber, S. Legg, and S. Lozier. 2011. Commentary: Mentoring
groups— A non-exit strategy for women in physical oceanography.
Oceanography 24(2):17–20, https://doi.org/10.5670/oceanog.2011.43.
Lozier, M.S. 2005. A community effort toward the retention of women in phys-
ical oceanography. Oceanography 18(1):35–38, https://doi.org/10.5670/
oceanog.2005.68.
Lozier, M.S. 2009. Conference report: A successful first Pattullo Conference.
Oceanography 22(1):224–225, https://doi.org/10.5670/oceanog.2009.25.
On Mentoring of Graduate Students
FROM THE PRESIDENT
Oceanography | Vol.31, No.1
RIPPLE MARKS: THE STORY BEHIND THE STORY
Icon of Chesapeake Winter
Still Graces the Bay
“They came back. This winter.” Biologist Donald Webster’s voice has a wistful note, won-
dering if the king of ducks, as the beautiful, crimson-headed canvasback is known, will
return to rule Chesapeake Bay in future seasons.
Bundled in parka, gloves, and hat, Webster, waterfowl coordinator for the Maryland
Department of Natural Resources, raises his binoculars near a seawall at the confluence
of the Chesapeake and the Choptank River in Cambridge, Maryland. The overlook is
a mecca for wintering canvasbacks and other ducks. Chesapeake Bay is the largest
estuary in the United States and one of the most productive water bodies in the world,
attracting myriad waterfowl species.
“Canvasbacks, the ducks everyone comes to see, are usually here in force by
Christmas, sometimes by Thanksgiving,” Webster says. “They stay through early to mid-
March, then they’re gone, heading north to nesting grounds.”
Chesapeake skies fill with migrating
ducks—canvasbacks, buffleheads, greater
and lesser scaup, and many others—from
December through March. The bay is the
Atlantic Coast’s most important water-
fowl migration and wintering area. The
Chesapeake and its 19 major tributaries
offer refuge to 24 species of ducks as well
as Canada geese, greater snow geese,
and tundra swans.
“Long-term worsening of the bay’s
water quality, however, and loss of habitat,
especially the grasses so many of these
birds depend upon, have contributed to
declines in wintering waterfowl popula-
tions,” says Webster.
SEESAWING GRASS ESTIMATES
An estimated 97,433 acres (400 km2)
of submerged aquatic vegetation (SAV)
remained in the bay and its tributaries in
2016, down from historic levels that may
have reached more than 600,000 acres
(2,500 km2).
There’s good news, however, in the
2016 estimate. It’s an 8% increase over
2015, and more than twice the SAV in the
bay in 2013.
In 2011, the Chesapeake’s SAV declined
to 48,195 acres (195 km2), a result of the
effects of Hurricane Irene and Tropical
Storm Lee. The storms sent a flood of
sediment cascading down rivers and into
the bay. After 2011, conditions became
relatively dry, reducing the flow of
grass-smothering sand and mud. More
sunlight reached submerged grasses,
allowing them to rebound. In return,
the SAV filtered runoff, helping keep
Chesapeake waters clear.
Forty years ago, SAV reached what
may be its lowest point in parts of the
bay. Another major storm, Tropical Storm
Agnes in 1972, nearly wiped out the SAV
at Susquehanna Flats, an expansive bed
of grasses where the Susquehanna River
Oceanography | Vol.31, No.1
BY CHERYL LYN DYBAS
PHOTOS BY ILYA RASKIN
SKEINS OF WATERFOWL
On this late January morning with calm
winds and temperatures that hover just
above freezing, the canvasbacks’ red
heads stand out in quiet, winter-dark
waters. The ducks glide near the sea-
wall, where a dozen photographers jostle
for the quintessential shot of an iconic
Chesapeake species. “This place is known
as the ‘wall of shame,’” laughs Webster,
“because it’s almost too easy to get great
canvasback pictures here.”
After the warm winter of 2015–2016
and its low numbers of canvasbacks,
they’ve arrived in large flocks this season
(2016–2017).