NOAA Teacher at Sea
Trevor Hance
Aboard R/V Hugh R. Sharp
June 12 – 24, 2015
Mission: Sea Scallop Survey
Geographical area: New England/Georges Bank
Date: June 17, 2015
Science and Technology Log
We’re now at the half-way point of this journey and things continue to run well, although the weather has picked up a bit. I mentioned to one of my fellow crew members that the cloud cover and cool weather reminded me of “football and gumbo” and he said, “Yeah… around here, we just call it ‘June’.” Touché, my friend.
I am continually impressed by both the ship’s crew and the science party’s ability to identify work that needs to be done and set a course towards continued, uninterrupted success of the mission. The depth and breadth of knowledge required to navigate (all puns intended!) extended scientific expeditions requires professional dedication matched with a healthy sense of humor, and it is truly an honor to be invited to participate in this unique opportunity for teachers. I am learning volumes each day and will forever treasure this wonderful adventure. Thanks again, NOAA!
Science and Math
My instructional path is rooted in constructivist learning theory, and I work diligently to secure resources for my students to have authentic, project-based learning experiences where they determine budgets, necessary tools and physically build things that we use on our campus.
Most recently, my math class designed and built some raised mobile garden beds that will be used by the youngest students on our campus as well as those with unique mobility challenges. Through these hands-on learning experiences, I expect my students to develop a solid working-level of mathematic and scientific literacy, and I’m proud of the fact that when I present a new concept, my students never ask “When am I going to have to use this in real life?”
I believe fifth grade students can understand any science concept, and I am seeing additional opportunities to test that idea using what I learn out here, so thought I’d share a few examples of some of the things I’ve learned as they will be presented in my G5 classroom starting this fall.
With a basic understanding of the objective for this survey presented in the last blog, I’ll explore some of the geographic and hydrodynamic concepts associated with this part of the world in this post. In the next blog, I’ll dive deeper into a specific study of scallops and lobsters, and in the fourth post I’ll talk more about the effects of current marine/fisheries management practices, with particular focus on those relating to closed areas (somewhat akin to the Balcones Preserve behind our campus.)
Georges Bank…water, water everywhere, time for a bath(ology)
We all know that water is central to our survival, and “playing” with water provides a strong anchoring point (am I pushing the puns too far?) for understanding systems relationships as students progress through their educational path. For the past couple of years, I have been accepted to participate in a “Scientist in Residence” program offered through the University of Texas’ Environmental Science Institute, which pairs local teachers with a graduate level scientist for an entire school year. In my first year, I was paired with (recently graduated) Dr. Kevin Befus, whose work focuses on hydrology. Through my work with Kevin (note to students: I can call him Kevin, you call him Dr. – he’s earned it!), I learned much about water and the importance of “flow,” and when you understand some of the “flow” relating the world’s most productive fishery, Georges Bank, I think you’ll agree with me.
Georges Bank is an oval shaped shoal, which is essentially a submerged island that lies about 60 miles off the coast of Cape Cod, and covers nearly 150 square miles. “The Bank,” or “Georges,” as many people aboard the vessel refer to it, is only recently submerged (i.e. – within the last 100,000 years). As recently as ten years ago scientists found mastodon tusks on the Bank, and legend holds that in the early 1900s, fishing vessels would stop on an island in Georges Bank (now submerged to about 10m) and play baseball (note: I have yet to find a bat and ball aboard the Sharp, but hope remains!)
Just like good soil helps support plant life, good water helps support marine life, and the key to the abundant life along Georges Bank lies in the nutrient rich water that is pushed towards the surface as it approaches Georges from the north and south. On three sides of Georges Bank, the sea floor drops dramatically. To the north sits the Gulf of Maine, which drops to approximately 1000m deep, and to the east and south, the Atlantic Ocean quickly reaches depths of over 2500m.
Almost all water enters Georges Bank from the north via the Gulf of Maine. The Gulf of Maine is fed via natural river discharges (including those from the Damariscotta and Merrimack Rivers) and the Labrador Currents that hug the coastline south around Nova Scotia before turning west into the Gulf of Maine. Water also enters the Gulf of Maine through The North Channel on the east side of Maine from the Gulf Stream and that very salty, warm water is important, particularly when it comes to the biology of Georges Bank (as we’ll look at more in the next blog entry.)
Much of the water exiting the Gulf of Maine enters The Great South Channel, which is something like a “river in the ocean” that runs between Cape Cod and Georges Bank. Deep within the Channel is a “sill,” which is a type of landform barrier, similar to a fence that doesn’t reach up to the surface. The sill rises quickly from the sea floor and extends across the Great South Channel, effectively blocking the deepest, densest water, resulting in strong, deep, cold currents that are pushed east around the outer edge of Georges Bank before returning towards the United States’ east coast in a clockwise path, resembling “from 11 until 7” on a clock’s face. Yes students, I do mean an analog clock!
After the deep currents make their way back to southern Massachusetts, they head south on the Longshore Coastal Current, which is like a “jet” of water that sprints southbound right along the eastern United States coastline (note: those of us from the Gulf Coast frequently hear friends wonder why the Atlantic Ocean is so cold when they visit Florida, and this is partly why!)
At this point, I’m going to take a moment and speak directly to my students: Just as the water flows into and mixes at Georges Bank from different directions, I’m hopeful that your thoughts are starting to swirl as you recognize the connection to concepts we have studied relating to energy, weather and climate, mixtures and solutions, salinity (and conductivity/resisitivity) and density (and buoyancy) – they are all evident and part of this story! And YES — this WILL be on the test!
While the deep-water currents that circle around Georges Bank’s edges exist year-round, in the winter there isn’t tremendous difference in the three primary water measurements (“Conductivity, Temperature and Density,” or “CTD”) between the water in The Great South Channel versus that sitting atop Georges Bank. As you might recognize, in normal conditions, there shouldn’t be much cause for warm or fresh water to be added to the area during the cold winter months, as our part of the world seems to slow down and a goodly amount of water freezes. In the spring, however, the northern hemisphere warms and ice melts, adding lots of warmer-and-fresh water to the Labrador Current and river discharges I mentioned above, ultimately sending that water south towards Georges Bank. At this point, things get really interesting…
The new, warmer water is less dense than the deeper water. The warm and cold water ultimately completely decouple and become fully stratified (i.e. – there are two distinct layers of water sitting one on top of the other.) The stratified layers move in separate currents: the deeper, colder, more-dense layer continues its clockwise, circular path along the outer edge of the Bank before heading south; and the top, “lighter” layer gets “trapped” in a clockwise “gyre,” which is the formal word for a swirling “racetrack” of a current that sits on the Bank. This gyre goes full-circle atop Georges Bank approximately 2.5 to 3 times per summer season.
Bigelow and Bumpus: Going with the Flow
The stratified/gyre relationship was confirmed almost 90 years ago by Henry Bigelow (note: those familiar with NOAA will no doubt recognize his name for several reasons, including the fact that a ship in the NOAA fleet is named after him). Essentially, Bigelow used a type of “weighted-kite-and-floating-buoy” system to observe and confirm the two layers. Bigelow’s “floating-buoy” was tied to the “weighted-kite” (actually called a drogue) and set at various depths, with each depth tested as an independent variable. Once set, Bigelow drogued the water, chasing after the floats-and-kites, ultimately confirming that the stratified currents did in fact exist. When you look at our dry lab here on the Sharp, complete with dozens of computers constantly monitoring hundreds of variables, Bigelow’s paper-and-pencil study aboard a 3-masted schooner is pretty awesome, and makes me feel a little lazy!
In a different study conducted later in the 1900s that perhaps might evoke romantic images of the sea, physical oceanographer Dean Bumpus performed a study similar to Bigelow’s, but in a slightly different fashion. Over the course of a few years, Bumpus put notes in over 3,000,000 test-tubes and set them adrift from Georges Bank. The notes provided instructions on how to contact Bumpus if found, and he used the returned notes to determine things like current speed and direction. While I’m not sure if Bumpus also used this methodology to find true love, the experiment did reinforce the idea of the currents that exist around Georges Bank!
Yep, it’s pretty cool to hear stories of those old-school scientists getting their names in the history books by just going with the flow.
Gulf Coast Style Kicking It Up North
One other unique hydrologic influence on Georges Bank relates to “meanderings” by the Gulf Stream. Normally, as the Longshore Coastal Current sprints southbound along the east coast faster than a recent retiree snowbirding to Florida, a little further offshore, the Gulf Stream is heading north, bringing with it warm water. As the water moves towards Georges Bank, the bank does its thing, acting as a berm (my BMX students might better identify with that term), and pushes that water off towards the east. The warm water ultimately reaches England, and when mixed with the cool air there, causes the cloudy conditions and fog we frequently associate with life in the U.K.
The unique aspect of this relationship occurs when, from time to time, the Gulf Stream misses the turn and a “slice” of the Gulf Stream breaks away. When this happen, the split portion spins in a counter clockwise fashion and breaks into Georges Bank, bringing with it warm water — and all the chemistry and biology that comes with it. More on that later…
Water Summary
So, in a nutshell, that’s the system. The coldest water at the headwaters of rivers in Maine and that in the arctic freezes and becomes ice. Deep water doesn’t have access to the warm sunlight, so it stays colder than the warm, less dense water at the surface that is hoping for the chance to boil over and soar up into the skies as water vapor. Newton tells us that things like to stay still, but will stay in motion once they get started. Things like sills and submerged islands get in the way of flowing water (yeah, more Newton here), resulting in mixtures and unique current patterns.
From a biological standpoint, the traditional currents associated with Georges Bank bring the deep, nutrient rich waters to the surface. As that water is pushed to the surface, algae and phytoplankton grow in great numbers. Phytoplankton attracts zooplankton, fish larvae eat the zooplankton, and eventually, “circle gets a square,” the trophic pyramid is complete, and nature finds its equilibrium.
If only it was that easy, right?
Unfortunately, the frequency of warmer weather over the past century has had an impact on the ecology of Georges Bank. Scientists have noticed more warm water from the north as ice continues to melt and increased frequency of the Gulf Stream meandering from the south. I’m told that 20 years ago, Red Hake were rare here, but I’ve noticed very few of our dredges where Red Hake weren’t at least the plurality, if not majority, of fish we caught. As Mr. Dylan says, “the times, they are a changin’.”
Okay. That’s it! Congratulations students! You have passed Oceanography: Hydrodynamics Short Course 101 and it is time to move on to Oceanography: Shellfish Biology 101, which we will cover in the next blog.
Lagniappe: Dr. Scott Gallager
My students and friends know that I am continually working to learn new things. I am surrounded by experts on this cruise and I need to go ahead and admit it: I feel sorry for these folks because they are trapped and can’t escape the questions I’ll wind up asking them about their incredibly interesting work!
As I mentioned earlier, depth of knowledge is important to success of these missions, but, breadth is equally important. Addressing challenges and solving problems from different perspectives is essential, and it sure would be nice to have a Boy Scout out here. Oh wait, we actually have a long time Scout Master among us, Dr. Scott Gallagher. There, I feel better already…
Scott is a scientist at the Woods Hole Oceanographic Institution (“WHOI”), where his work focuses on biological and physical interactions in oceanography, which can perhaps be a little better explained as “working to understand the physical properties and processes of the ocean that impact biological abundance and populations (aka – distributions).” In other words, “where are the scallops, how many are there, and why are they there and at that number?”
From a scientific perspective, there are three primary controls to analyze when studying shellfish populations: the total amount of larvae spawned; the transportation, or “delivery”, of the larvae through the water column to the place where they settle; and, post-settlement predatory relationships (aka – the sea stars, crabs, and humans all out to feast on these delicious creatures)… Seems like an easy-peasy career, right? (I kid. I kid.)
Scott cut his teeth as an undergrad at Cornell, starting off in electrical engineering, and ultimately earning degrees in both pre-med and environmental science (see, I told you he could see things from a variety of perspectives!). In his environmental science courses, Scott studied the Seneca and Cayuga Lakes, and after graduating from Alfred University/Cornell University, moved on and earned a master’s degree in Marine Biology at the University of Long Island. Over the next several years, he worked at Woods Hole as a research assistant, first working in bivalve (shellfish) ecology, and quickly moving up through the ranks to research specialist. After a couple of years at WHOI, the magnitude and awesome wonder of the life in our oceans presented Scott with more questions than answers, and he realized it was time to return to school and obtain his PhD so he could start answering some of the questions swimming around in his head (okay, no more puns, I promise).
In our discussion, Scott described the challenge of decoupling the biological processes of the ocean as a fascinating mystery novel that never ends, and never allows you to put the book down or stop turning the pages to see what comes next. After only a week out here with these good folks, it is evident that passion and curiosity exists in each of them, and it is really cool to feel their continued excitement about their work.
Aboard the ship, I’ve been fortunate to spend some time working with Scott in the wet-lab, where he helps conduct a more intensive study of a sample of 5-7 scallops from each dredge, according to survey protocol: taking photos, measuring the scallop size and weight, and recording whether it is male or female.
While the survey work is the mission of this cruise, it was the development and operational support for the HabCam that really got Scott working aboard these cruises, and members of his team are aboard each of the three legs every summer to participate in the survey work and provide technical assistance for the HabCam. I think of my time driving the HabCam of what it must be like to explore Mars with Curiosity.
In addition to his mission-specific field-work, Scott has set up an onboard live aquarium in one part of the deck, using nothing more than an air hose, fresh sea water, and a tote. The aquarium is a temporary home for many of the unique species we’ve caught on our dredge. Most species are only kept long enough for me to nerd-out and take some photos, and it has been very interesting to see the interaction of the animals in the confined habitat that would normally only be seen on the sea floor.
Photoblog:
Dredge playlist: Metallica, Dierks Bentley, Spoon, The National
Special thanks to Dr. Gallager for his help with this one.
Okay, that’s it, class dismissed…
Mr. Hance
