Kimberly Scantlebury: It’s All About the Little Things, May 8, 2017

NOAA Teacher at Sea

Kimberly Scantlebury

Aboard NOAA Ship Pisces

May 1-May 12, 2017

Mission: SEAMAP Reef Fish Survey

Geographic Area of Cruise: Gulf of Mexico

Date: May 8, 2017

Weather Data from the Bridge

Time: 18:00

Latitude: 2755.757 N, Longitude: 9200.0239 W

Wind Speed: 14.21  knots, Barometric Pressure: 1015.3 hPa

Air Temperature: 24.56  C, Water Temperature: 24.4  C

Salinity: 36.37  PSU, Conditions: 50% cloud cover, light wind, seas 2-4 feet

Science and Technology Log

IMG_2969

The CTD

The CTD (conductivity, temperature, depth) array is another important tool. It goes down at each station, which means data is captured ten-twelve times a day. It drops 50 m/min so it only takes minutes to reach the bottom where other winch/device systems can take an hour to do the same. This array scans eight times per second for the following environmental factors:

  • Depth (m)
  • Conductivity (converts to salinity in ppt)
  • Temperature (C)
  • Dissolved oxygen (mg/mL)
  • Transmissivity (%)
  • Fluorescence (mg/m^3)
  • Descent rate (m/sec)
  • Sound velocity (m/sec)
  • Density (kg/m^3)

There are two sensors for most readings and the difference between them is shown in real time and recorded. For example, the dissolved oxygen sensor is most apt to have calibration issues. If the two sensors are off each other by 0.1 mg/L then something needs to be done.

Software programs filter the data to cut out superfluous numbers such as when the CTD is acclimating in the water for three minutes prior to diving. Another program aligns the readings when the water is working through the sensors. Since a portion of water will reach one sensor first, then another, then another, and so on, the data from each exact portion of water is aligned with each environmental factor. There are many other sophisticated software programs that clean up the data for use besides these two.

These readings are uploaded to the Navy every twelve hours, which provides almost real-time data of the Gulf. The military uses this environmental data to determine how sound will travel through sound channels by locating thermoclines as well as identifying submarines. NOAA describes a thermocline as, “the transition layer between warmer mixed water at the ocean’s surface and cooler deep water below.” Sound channels are how whales are able to communicate over long distances.

NOAA Ocean Explorer: Sound in the Sea 2001

This “channeling” of sound occurs because of the properties of sound and the temperature and pressure differences at different depths in the ocean. (NOAA)

The transmissometer measures the optical properties of the water, which allows scientists to track particulates in the water. Many of these are clay particles suspended in the water column. Atmospheric scientists are interested in particulates in the air and measure 400 m. In the water, 0.5 m is recorded since too many particulate affects visibility very quickly. This affects the cameras since light reflecting off the clay can further reduce visibility.   

Fluorescence allows scientists to measure chlorophyll A in the water. The chlorophyll molecule is what absorbs energy in photosynthetic plants, algae, and bacteria. Therefore, it is an indicator of the concentration of organisms that make up the base of food chains. In an ecosystem, it’s all about the little things! Oxygen, salinity, clay particles, photosynthetic organisms, and more (most we can not actually see), create a foundation that affects the fish we catch more than those fish affect the little things.  

The relationship between abiotic (nonliving) and biotic (living) factors is fascinating. Oxygen is a great example. When nitrates and phosphates wash down the Mississippi River from the breadbasket of America, it flows into the Gulf of Mexico. These nutrients can make algae go crazy and lead to algae blooms. The algae then use up the oxygen, creating dead zones. Fish can move higher up the water column or away from the area, but organisms fixed to the substrate (of which there are many in a reef system) can not. Over time, too many algae blooms can affect the productivity of an area.

Salt domes were created millions of years ago when an ancient sea dried up prior to reflooding into what we have today. Some salt domes melted and pressurized into super saline water, which sinks and pools. These areas create unique microclimates suitable to species like some mussels. A microclimate is a small or restricted area with a climate unique to what surrounds it.

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The ship’s sonar revealing a granite spire a camera array was deployed on.

Another great example is how geology affects biology. Some of these salt domes collapsed leaving granite spires 30-35 meters tall and 10 meters across. These solid substrates create a magical biological trickle down effect. The algae and coral attach to the hard rock, and soon bigger and bigger organisms populate this microclimate. Similar microclimates are created in the Gulf of Mexico from oil rigs and other hard surfaces humans add to the water.

Jillian’s net also takes a ride with the CTD. She is a PhD student at Texas A&M University studying the abundance and distribution of zooplankton in the northern Gulf of Mexico because it is the primary food source of some commercially important larval fish species. Her net is sized to capture the hundreds of different zooplankton species that may be populating the area. The term zooplankton comes from the Greek zoo (animal) and planktos (wanderer/drifter). Many are microscopic, but Jillian’s samples reveal some translucent critters you can see with the naked eye. Her work and the work of others like her ensures we will have a deeper understanding of the ocean.   

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Personal Log

Prior to this I had never been to the Gulf of Mexico other than on a cruise ship (not exactly the place to learn a lot of science). It has been unexpected to see differences and parallels between the Gulf of Mexico and Gulf of Maine, which I am more familiar. NOAA scientist, John, described the Gulf to me as, “a big bathtub.” In both, the geology of the area, which was formed millions of years ago, affects that way these ecosystems run.   

Quote of the Day:
Jillian: “Joey, are we fishing at this station?”
Joey: “I dunno. I haven’t had my coffee yet.”
Jillian: “It’s 3:30 in the afternoon!”

Did You Know?

Zooplankton in the Gulf of Mexico are smaller than zooplankton in the Gulf of Maine. Larger species are found in colder water.  

why_zoo

Zooplankton under microscope (NOAA)

Michael Wing: Introduction to El Niño, July 22, 2015

NOAA Teacher at Sea
Michael Wing
Aboard R/V Fulmar
July 17 – 25, 2015

Mission: 2015 July ACCESS Cruise
Geographical Area of Cruise: Pacific Ocean west of Bodega Bay, California
Date: July 22, 2015

Weather Data from the Bridge: Northwest wind 15-25 knots, wind waves 3’-5’, northwest swell 4’ – 6’ at eight seconds, overcast.

Science and Technology Log

UC Davis graduate student and Point Blue Conservation Science intern Kate Davis took some plankton we collected to the Bodega Marine lab in Bodega Bay. She said she is seeing “tropical” species of plankton. A fellow graduate student who is from Brazil peeked into the microscope and said the plankton looked like what she sees at home in Brazil. The flying fish we saw is also anomalous, as is the number of molas (ocean sunfish) we are seeing. Plankton can’t swim, so some of our water must have come from a warm place south or west of us.

Farallones

The Farallon Islands are warmer this year

The surface water is several degrees warmer than it normally is this time of year. NOAA maintains a weather buoy near Bodega Bay, California that shows this really dramatically. Click on this link – it shows the average temperature in blue, one standard deviation in gray (that represents a “normal” variation in temperatures) and the actual daily temperature in red.

NOAA buoy data

Surface seawater temperatures from a NOAA buoy near Bodega Bay, California

http://bml.ucdavis.edu/boon/climatology.html

As you can see, the daily temperatures were warm last winter and basically normal in the spring. Then in late June they shot up several degrees, in a few days and have stayed there throughout this month. El Niño? Climate change? The scientists I am with say it’s complicated, but at least part of what is going on is due to El Niño.

Ryan at flying bridge

San Francisco State University student and Point Blue intern Ryan Hartnett watches El Nino

So what exactly is El Niño?

My students from last year know that the trade winds normally push the surface waters of the world’s tropical oceans downwind. In the Pacific, that means towards Asia. Water wells up from the depths to take its place on the west coasts of the continents, which means that places like Peru have cold water, lots of fog, and good fishing. The fishing is good because that deep water has lots of nutrients for phytoplankton growth like nitrate and phosphate (fertilizer, basically) and when it hits the sunlight lots of plankton grow. Zooplankton eat the phytoplankton; fish eat the zooplankton, big fish eat little fish and so on.

During an El Niño event, the trade winds off the coast of Peru start to weaken and that surface water bounces back towards South America. This is called a Kelvin wave. Instead of flowing towards Asia, the surface water in the ocean sits there in the sunlight and it gets warmer. There must be some sort of feedback mechanism that keeps the trade winds weak, but the truth is that nobody really understands how El Niño gets started. We just know the signs, which are (1) trade winds in the South Pacific get weak (2) surface water temperatures in the eastern tropical pacific rise, (3) the eastern Pacific Ocean and its associated lands get wet and rainy, (4) the western Pacific and places like Australia, Indonesia, and the Indian Ocean get sunny and dry.

This happens every two to seven years, but most of the time the effect is weak. The last time we had a really strong El Niño was 1997-1998, which is when our current cohort of high school seniors was born. That year it rained 100 inches in my yard, and averaged over an inch a day in February! So, even though California is not in the tropics we feel its effects too.

Sausalito sunset

Sunset from the waterfront in Sausalito, California

We are in an El Niño event now and NOAA is currently forecasting an excellent chance of a very strong El Niño this winter.

NOAA map

Sea surface temperature anomalies Summer 2015. Expect more red this winter.

What about climate change and global warming? How is that related to El Niño? There is no consensus on that; we’ve always had El Niño events and we’ll continue to have them in a warmer world but it is possible they might be stronger or more frequent.

Personal Log

So, is El Niño a good thing? That’s not a useful question. It’s a part of our climate. It does make life hard for the seabirds and whales because that layer of warm water at the surface separates the nutrients like nitrate and phosphate, which are down deep, from the sunlight. Fewer phytoplankton grow, fewer zooplankton eat them, there’s less krill and fish for the birds and whales to eat. However, it might help us out on land. California’s drought, which has lasted for several years now, may end this winter if the 2015 El Niño is as strong as expected.

Golden Gate Bridge

Rain will come again to California

Did You Know? El Niño means “the boy” in Spanish. It refers to the Christ child; the first signs of El Niño usually become evident in Peru around Christmas, which is summer in the southern hemisphere. The Spanish in colonial times were very fond of naming things after religious holidays. You can see that in our local place names. For instance, Marin County’s Point Reyes is named after the Feast of the Three Kings, an ecclesiastical holy day that coincided with its discovery by the Spanish. There are many other examples, from Año Nuevo on the San Mateo County coast to Easter Island in Chile.

Window selfie

Michael Wing takes a selfie in his reflection in the boat’s window

Michael Wing: How to Sample the Sea, July 20, 2015

NOAA Teacher at Sea
Michael Wing
Aboard R/V Fulmar
July 17 – 25, 2015

Mission: 2015 July ACCESS Cruise
Geographical Area of Cruise: Pacific Ocean west of Marin County, California
Date: July 20, 2015

Weather Data from the Bridge: 15 knot winds gusting to 20 knots, wind waves 3-5’ and a northwest swell 3-4’ four seconds apart.

Science and Technology Log

On the even-numbered “lines” we don’t just survey birds and mammals. We do a lot of sampling of the water and plankton.

Wing on Fulmar

Wing at rail of the R/V Fulmar

We use a CTD (Conductivity – Temperature – Depth profiler) at every place we stop. We hook it to a cable, turn it on, and lower to down until it comes within 5-10 meters of the bottom. When we pull it back up, it has a continuous and digital record of water conductivity (a proxy for salinity, since salty water conducts electricity better), temperature, dissolved oxygen, fluorescence (a proxy for chlorophyll, basically phytoplankton), all as a function of depth.

CTD

Kate and Danielle deploy the CTD

We also have a Niskin bottle attached to the CTD cable. This is a sturdy plastic tube with stoppers at both ends. The tube is lowered into the water with both ends cocked open. When it is at the depth you want, you clip a “messenger” to the cable. The messenger is basically a heavy metal bead. You let go, it slides down the cable, and when it strikes a trigger on the Niskin bottle the stoppers on both ends snap shut. You can feel a slight twitch on the ship’s cable when this happens. You pull it back up and decant the seawater that was trapped at that depth into sample bottles to measure nitrate, phosphate, alkalinity, and other chemical parameters back in the lab.

Niskin bottle

Niskin bottle

When we want surface water, we just use a bucket on a rope of course.

We use a hoop net to collect krill and other zooplankton. We tow it behind the boat at a depth of about 50 meters, haul it back in, and wash the contents into a sieve, then put them in sample bottles with a little preservative for later study. We also have a couple of smaller plankton nets for special projects, like the University of California at Davis graduate student Kate Davis’s project on ocean acidification, and the plankton samples we send to the California Department of Health. They are checking for red tides.

Hoop net

Hoop net

We use a Tucker Trawl once a day on even numbered lines. This is a heavy and complicated rig that has three plankton nets, each towed at a different depth. It takes about an hour to deploy and retrieve this one; that’s why we don’t use it each time we stop. The Tucker trawl is to catch krill; which are like very small shrimp.  During the day they are down deep; they come up at night.

Tucker trawl

Part of the Tucker trawl

 

krill

A mass of krill we collected. The black dots are their eyes.

What happens to these samples? The plankton from the hoop net gets sent to a lab where a subsample is taken and each species in the subsample is counted very precisely. The CTD casts are shared by all the groups here – NOAA, Point Blue Conservation Science, the University of California at Davis, San Francisco State University. The state health department gets its sample. San Francisco State student Ryan Hartnett has some water samples he will analyze for nitrate, phosphate and silicate. All the data, including the bird and mammal sightings, goes into a big database that’s been kept since 2004. That’s how we know what’s going on in the California Current. When things change, we’ll recognize the changes.

Personal Log

They told me “wear waterproof pants and rubber boots on the back deck, you’ll get wet.” I thought, how wet could it be? Now I understand. It’s not that some water drips on you when you lift a net up over the stern of the boat – although it does. It’s not that waves splash you, although that happens too. It’s that you use a salt water hose to help wash all of the plankton from the net into a sieve, and then into a container, and to fill wash bottles and to wash off the net, sieve, basins, funnel, etc. before you arrive at the next station and do it all again. It takes time, because you have to wash ALL of the plankton from the end of the net into the bottle, not just some of it. You spend a lot of time hosing things down. It’s like working at a car wash except with salty water and the deck is pitching like a continuous earthquake.

The weather has gone back to “normal”, which today means 15 knot winds gusting to 20 knots, wind waves 3-5’ and a northwest swell 3-4’ only four seconds apart. Do the math, and you’ll see that occasionally a wind wave adds to a swell and you get slapped by something eight feet high. We were going to go to Bodega Bay today; we had to return to Sausalito instead because it’s downwind.

sea state

The sea state today. Some waves were pretty big.

We saw a lot of humpback whales breaching again and again, and slapping the water with their tails. No, we don’t know why they do it although it just looks like fun. No, I didn’t get pictures. They do it too fast.

Did You Know? No biologist or birder uses the word “seagull.” They are “gulls”, and there are a lot of different species such as Western gulls, California gulls, Sabine’s gulls and others. Yes, it is possible to tell them apart.

DJ Kast, Interview with Megan Switzer and the Basics of the CTD/ Rosette, May 28, 2015

NOAA Teacher at Sea
Dieuwertje “DJ” Kast
Aboard NOAA Ship Henry B. Bigelow
May 19 – June 3, 2015

Mission: Ecosystem Monitoring Survey
Geographical area of cruise:
Gulf of Maine
Date: May 28, 2015, Day 11 of Voyage

Interview with Student Megan Switzer

Megan Switzer and her sampling collecting. Photo by: DJ Kast

Megan Switzer and her sampling collecting. Photo by: DJ Kast

Chief Scientists Jerry Prezioso and graduate oceanography student Megan Switzer

Chief Scientist Jerry Prezioso and graduate oceanography student Megan Switzer

Megan Switzer is a Masters student at the University of Maine in Orono. She works in Dave Townsend’s lab in the oceanography department. Her research focuses on interannual nutrient dynamics in the Gulf of Maine. On this research cruise, she is collecting water samples from Gulf of Maine, as well as from Georges Bank, Southern New England (SNE), and the Mid Atlantic Bight (MAB). She is examining the relationship between dissolved nutrients (like nitrate and silicate) and phytoplankton blooms. This is Megan’s first research cruise!

In the generic ocean food chain, phytoplankton are the primary producers because they photosynthesize. They equate to plants on land. Zooplankton are the primary consumers because they eat the phytoplankton. There are so many of both kinds in the ocean. Megan is focusing on a particular phytoplankton called a diatom; it is the most common type of phytoplankton found in our oceans and is estimated to contribute up to 45% of the total oceanic primary production (Yool & Tyrrel 2003). Diatoms are unicellular for the most part, and a unique feature of diatom cells is that they are enclosed within a cell wall made of silica called a frustule.

Diatom Frustules. Photo by:  3-diatom-assortment-sems-steve-gschmeissner

Diatom Frustules. Photo by: Steve Schmeissner

Diatoms! PHOTO BY:

Diatoms! Photo by: Micrographia

The frustules are almost bilaterally symmetrical which is why they are called di (2)-atoms. Diatoms are microscopic and they are approximately 2 microns to about 500 microns (0.5 mm) in length, or about the width of a human hair. The most common species of diatoms are: Pseudonitzchia, Chaetocerous, Rhizosolenia, Thalassiosira, Coschinodiscus and Navicula.

Pseudonitzchia. Photo by National Ocean Service

Pseudonitzchia. Photo by National Ocean Service

Thalassiosira. Photo by: Department of Energy Joint Genome Institute

Thalassiosira. Photo by: Department of Energy Joint Genome Institute

Photo of Coscinodiscus by:

Photo of Coscinodiscus

Diatoms also have ranges and tolerances for environmental variables, including nutrient concentration, suspended sediment, and flow regime.  As a result, diatoms are used extensively in environmental assessment and monitoring. Furthermore, because the silica cell walls are inorganic substances that take a long time to dissolve, diatoms in marine and lake sediments can be used to interpret conditions in the past.

In the Gulf of Maine, the seafloor sediment is constantly being re-suspended by tidal currents, bottom trawling, and storm events, and throughout most of the region there is a layer of re-suspended sediment at the bottom called the Bottom Nepheloid Layer. This layer is approximately 5-30 meters thick, and this can be identified with light attenuation and turbidity data. Megan uses a transmissometer, which is an instrument that tells her how clear the water is by measuring how much light can pass through it. Light attenuation, or the degree to which a beam of light is absorbed by stuff in the water, sharply increases within the bottom nepheloid layer since there are a lot more particles there to block the path of the light. She also takes a water sample from the Benthic Nepheloid Layer to take back to the lab.

Marine Silica Cycle by Sarmiento and Gruber 2006

Marine Silica Cycle by Sarmiento and Gruber 2006

Megan also uses a fluorometer to measure the turbidity at various depths. Turbidity is a measure of how cloudy the water is. The water gets cloudy when sediment gets stirred up into it. A fluorometer measures the degree to which light is reflected and scattered by suspended particles in the water. Taken together, the data from the fluorometer and the transmissometer will help Megan determine the amount of suspended particulate material at each station. She also takes a water sample from the Benthic Nepheloid layer to take back to the lab. There, she can analyze the suspended particles and determine how many of them are made out of the silica based frustules of sinking diatoms.

 This instrument is a Fluorometer and is used to measure the turbidity at various depths. Photo by: DJ Kast

This instrument is a Fluorometer and is used to measure the turbidity at various depths. Photo by: DJ Kast

She collects water at depth on each of the CTD/ Rosette casts.

Rosette with the 12 Niskin Bottles and the CTD. Photo by DJ Kast

Rosette with the 12 Niskin Bottles and the CTD. Photo by DJ Kast

Rosette with the 12 Niskin Bottles and the CTD. Photo by DJ Kast

Rosette with the 12 Niskin Bottles and the CTD. Photo by DJ Kast

Up close shot of the water sampling. Photo by DJ Kast

Up close shot of the water sampling. Photo by DJ Kast

CTD, Rosette, and Niskin Bottle basics.

The CTD or (conductivity, temperature, and depth) is an instrument that contains a cluster of sensors, which measure conductivity, temperature, and pressure/ depth.

Here is a video of a CTD being retrieved.

Depth measurements are derived from measurement of hydrostatic pressure, and salinity is measured from electrical conductivity. Sensors are arranged inside a metal housing, the metal used for the housing determining the depth to which the CTD can be lowered. Other sensors may be added to the cluster, including some that measure chemical or biological parameters, such as dissolved oxygen and chlorophyll fluorescence. Chlorophyll fluorescence measures how many microscopic photosynthetic organisms (phytoplankton) are in the water. The most commonly used water sampler is known as a rosette. It is a framework with 12 to 36 sampling Niskin bottles (typically ranging from 1.7- to 30-liter capacity) clustered around a central cylinder, where a CTD or other sensor package can be attached. The Niskin bottle is actually a tube, which is usually plastic to minimize contamination of the sample, and open to the water at both ends. It has a vent knob that can be opened to drain the water sample from a spigot on the bottom of the tube to remove the water sample. The scientists all rinse their bottles three times and wear nitrile or nitrogen free gloves to prevent contamination to the samples.

On NOAA ship Henry B. Bigelow the rosette is deployed  from the starboard deck, from a section called the side sampling station of this research vessel.

The instrument is lowered into the water with a winch operated by either Adrian (Chief Boatswain- in charge of deck department) or John (Lead Fishermen- second in command of deck department). When the CTD/Rosette is lowered into the water it is called the downcast and it will travel to a determined depth or to a few meters above the ocean floor. There is a conducting wire cable is attached to the CTD frame connecting the CTD to an on board computer in the dry lab, and it allows instantaneous uploading and real time visualization of the collected data on the computer screen.

 

CTD data on the computer screen. Photo by: DJ Kast

CTD data on the computer screen. Photo by: DJ Kast

The water column profile of the downcast is used to determine the depths at which the rosette will be stopped on its way back to the surface (the upcast) to collect the water samples using the attached bottles.

Niskin Bottles:

Messenger- The manual way to trigger the bottle is with a weight called a messenger. This is sent down a wire to a bottle at depth and hits a trigger button. The trigger is connected to two lanyards attached to caps on both ends of the bottle.  When the messenger hits the trigger, elastic tubing inside the bottle closes it at the specified depth.

Todd with the manually operated Niskin Bottle. Photo by: DJ Kast

Todd holding a messenger to trigger the manually operated Niskin Bottle. Photo by: DJ Kast

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Todd with the manually operated Niskin Bottle. Photo by: DJ Kast

Todd with the manually operated Niskin Bottle. Photo by: DJ Kast

Manual CTD fully cocked and ready to deploy. Photo by DJ Kast

Manual CTD fully cocked and ready to deploy. Photo by DJ Kast

Here is a video of how the manual niskin bottle closes: https://www.youtube.com/watch?v=qrqXWtbUc74

The other way to trigger Niskin bottles is electronically. The same mechanism is in place but an electronic signal is sent down the wire through insulated and conductive sea cables (to prevent salt from interfering with conductivity) to trigger the mechanism.

Here is a video of how it closes electronically: https://www.youtube.com/watch?v=YJF1QVe6AK8

Conductive Wire to CTD. Photo by DJ Kast

Conductive Wire to CTD. Photo by DJ Kast

Photo of the top of the CTD. Photo by DJ Kast

Photo of the top of the CTD showing the trigger mechanism in the center. Photo by DJ Kast

Top of the Niskin Bottles to show how the white wires are connected to the top.

Top of the Niskin Bottles shows how the lanyards are connected to the top. Photo by DJ Kast

The pin on the bottom is activated when an electronic signal is sent through the conductive sea cables. Photo by DJ Kast

The pin on the bottom is activated when an electronic signal is sent through the conductive sea cables. Photo by DJ Kast

Using the Niskin bottles, Megan collects water samples at various depths. She then filters water samples for her small bottles with a syringe and a filter and the filter takes out the phytoplankton, zooplankton and any particulate matter. She does this so that there is nothing living in the water sample, because if there is there will be respiration and it will change the nutrient content of the water sample.

Filtering out only the water using a syringe filter. Photo by DJ Kast

Filtering out only the water using a syringe filter. Photo by DJ Kast

Photo by: DJ Kast

Syringe with a filter on it. Photo by: DJ Kast

This is part of the reason why we freeze the sample in the -80 C fridge right after they have been processed so that bacteria decomposing can’t change the nutrient content either.

Diatoms dominate the spring phytoplankton bloom in the Gulf of Maine. They take up nitrate and silicate in roughly equal proportions, but both nutrients vary in concentrations from year to year. Silicate is almost always the limiting nutrient for diatom production in this region (Townsend et. al., 2010). Diatoms cannot grow without silicate, so when this nutrient is used up, diatom production comes to a halt. The deep offshore waters that supply the greatest source of dissolved nutrients to the Gulf of Maine are richer in nitrate than silicate, which means that silicate will be used up first by the diatoms with some nitrate left over. The amount of nitrate left over each year will affect the species composition of the other kinds of phytoplankton in the area (Townsend et. al., 2010).

The silica in the frustules of the diatom are hard to breakdown and consequently these structures are likely to sink out of the euphotic zone and down to the seafloor before dissolving. If they get buried on the seafloor, then the silicate is taken out of the system. If they dissolve, then the dissolved silicate here might be a source of silicate to new production if it fluxes back to the top of the water column where the phytoplankton grow.

Below are five images called depth slices. These indicate the silicate concentration (rainbow gradient) over a geographical area (Gulf of Maine) with depth (in meters) latitude and longitude on the x and y axis.

Depth slices of nitrate and silicate. Photo by:  This is the type of data Megan is hoping to process from this cruise.

Depth slices of nitrate and silicate. Photo by:  GOMTOX at the University of Maine
This is the type of data Megan is hoping to process from this cruise.

DJ Kast, Interview with Jessica Lueders-Dumont, May 22, 2015

NOAA Teacher at Sea
Dieuwertje “DJ” Kast
Aboard NOAA Ship Henry B. Bigelow
May 19 – June 3, 2015

Mission: Ecosystem Monitoring Survey
Geographical area of cruise: East Coast

Date: May 22, 2015, Day 4 of Voyage

 

Interview with Jessica Lueders-Dumont

Who are you as a scientist?

Jessica Lueders-Dumont is a graduate student at Princeton University and has two primary components of her PhD — nitrogen biogeochemistry and historical ecology of the Gulf of Maine.

Jessica Lueders- Dumont, graduate student at Princeton cleaning a mini bongo plankton net for her sample.

Jessica Lueders- Dumont, graduate student at Princeton cleaning a mini bongo plankton net for her sample. Photo by: DJ Kast

 What research are you doing?

Her two projects are, respectively,

A) Nitrogen cycling in the North Atlantic (specifically focused on the Gulf of Maine and on Georges Bank but interested in gradients along the entire eastern seaboard)

B) Changes in trophic level of Atlantic cod in the Gulf of Maine and on Georges Bank over the history of fishing in the region. The surprising way in which these two seemingly disparate projects are related is that part A effectively sets the baseline for understanding part B!

She is co-advised by Danny Sigman and Bess Ward. Danny’s research group focuses on investigating climate change through deep time, primarily by assessing changes in the global nitrogen cycle which are inextricably tied to the strength of the biological pump (i.e. biological-mediated carbon export and storage in the ocean). Bess’s lab focuses on the functional diversity of marine phytoplankton and bacteria and the contributions of these groups to various nitrogen cycling processes in the modern ocean, specifically as pertains to oxygen minimum zones (OMZs). She is also advised by a Olaf Jensen, a fisheries scientist at Rutgers University.

In both of these biogeochemistry labs,  nitrogen isotopes (referred to as d15N, the ratio of the heavy 15N nuclide to the lighter 14N nuclide in a sample compared to that of a known standard) are used to track nitrogen cycling processes. The d15N of a water mass is a result of the relative proportions of different nitrogen cycling processes — nitrogen fixation, nitrogen assimilation, the rate of supply, the extent of nutrient utilization, etc. These can either be constrained directly via 15N tracer studies or can be inferred from “natural abundance” nitrogen isotopic composition, the latter of which will be used as a tool for this project.

Nitrogen Cycle in the Ocean. Photo credit to: https://wordsinmocean.files.wordpress.com/2012/02/n-cycle.png

Nitrogen Cycle in the Ocean. Photo credit to: https://wordsinmocean.files.wordpress.com/2012/02/n-cycle.png

On this cruise she has 3 sample types — phytoplankton, zooplankton, and seawater nitrate — and two overarching questions that these samples will address: How variable is “baseline d15N” along the entire eastern seaboard, and does this isotopic signal propagate to higher trophic levels? Each sample type gives us a different “timescale” of N cycling on the U.S. continental shelf. She will be filtering phytoplankton from various depths onto filters, she will be collecting seawater for subsequent analysis in the lab, and she will be collecting zooplankton samples — all of which will be analyzed for nitrogen isotopic composition (d15N).

Biogeochemistry background: 

Biogeochemists look at everything on an integrated scale. We like to look at the box model, which looks at the surface ocean and the deep ocean and the things that exchange between the two.

The surface layer of the ocean: euphotic zone (approximately 0-150 m-but this range depends on depth and location and is essentially the sunlit layer); nutrients are scarce here.

When the top zone animals die they sink below the euphotic zone and into the aphotic zone (150 m-4000m), and the bacteria break down the organic matter into inorganic matter (nitrate (NO3), phosphate (PO4) and silicate (Si(OH)3.). In terms of climate, an important nutrient that gets cycled is carbon dioxide.We look at the nitrate, phosphate, and silicate as limiting factors for biological activity for carbon dioxide, we are essentially calculating these three nutrients to see how much carbon dioxide is being removed from the atmosphere and “pumped” into the deep sea.  This is called the biological pump. Additionally, the particulate matter that falls to the deep sea is called Marine Snow, which is tiny organic matter from the euphotic zone that fuels the deep sea environments; it is orders of magnitude less at the bottom compared to the top.

Cycling

Visual Representation of the aphotic and euphotic zones and the nutrients that cycle through them. Photo by: Patricia Sharpley

 

Did you know that the “Deep sea is really acidic, holds a lot of CO2 and is the biggest reservoir of C02 in the world?” – From Jessica Lueders- Demont, graduate student at Princeton.

One of the most important limiting factors for phytoplankton is nitrogen, which is not readily available in many parts of the global ocean. “A limiting nutrient is a chemical necessary for plant growth, but available in quantities smaller than needed for algae and other primary producers to increase their abundance. Organisms can grow and reproduce only when they have sufficient nutrients. For algae, the carbon source is CO2and this, at least in the surface water, has a constant value and is not limiting their growth. The limiting nutrients are minerals (such as Fe+2), nitrogen, and phosphorus compounds” (Patricia Sharpley 2010).

Conversely, phosphorus is the limiting factor on land. The most common nitrogen is molecular nitrogen or N2, which has a strong bond to break and biologically it is very expensive to fix from the atmosphere. 

Biological, chemical, and physical oceanography all work together in this biogeochemistry world and are needed to have a productive ocean. For example, we need the physical oceanography to upwell them to the surface so that the life in the euphotic zone can use them.

Activities on the ship that I am assisting Jessica with:

  • Zooplankton collected using mini bongos with a 165 micron mesh and then further filtered at meshes: 1000, 500, and ends with 250 microns, this takes out all of the big plankton that she is not studying and leaves only her own in her size range which is 165-200 microns.
  • She is collecting zooplankton water samples because it puts the phytoplankton that she is focusing on into perspective.
The last of the mesh buckets that's filtering for phytoplankton. Photo by: DJ Kast

The last of the mesh buckets that’s filtering for phytoplankton. Photo by: DJ Kast

    • Aspirator pump sucks out all of the water so that the zooplankton are left on a glass fiber filter (GFFs) on the filtration rack.

 

  • Aspirator pump that is on the side sucks out all of the air so that the plankton get stuck on the filters at the bottom of the cups seen here. Photo by: DJ Kast

    Aspirator pump that is on the side sucks out all of the air so that the plankton get stuck on the filters at the bottom of the cups seen here. Photo by: DJ Kast

  • Bottom of the cup after all the water has been sucked through. Photo by: DJ Kast

    Bottom of the cup after all the water has been sucked through. Photo by: DJ Kast

  • Jessica removing the filter with sterilized tweezers to place into a labeled petridish. Photo by: DJ Kast

    Jessica removing the filter with sterilized tweezers to place into a labeled petri dish. Photo by: DJ Kast

    Labeled petri dish with GFF of phytoplankton on it. Photo by: DJ Kast

    Labeled petri dish with GFF of phytoplankton on it. Photo by: DJ Kast

Video of this happening:

Phytoplankton filtering:

Jessica collecting her water sample from the Niskin bottle in the Rosette. Photo by DJ Kast

Jessica collecting her water sample from the Niskin bottle in the Rosette. Photo by DJ Kast

Up close shot of the spigot that releases water from Niskin bottle in the Rosette. Photo by DJ Kast

Up close shot of the spigot that releases water from Niskin bottle in the Rosette. Photo by DJ Kast

DJ Kast helping Jessica collect her 4 L of seawater from the Niskin bottle in the Rosette. Photo by Jerry P.

DJ Kast helping Jessica collect her 4 L of seawater from the Niskin bottle in the Rosette. Photo by Jerry P.

DJ and Jessica collect her 4 L of seawater from the Niskin bottle in the Rosette. Photo by Jerry P.

DJ and Jessica collect her 4 L of seawater from the Niskin bottle in the Rosette. Photo by Jerry P.

Chief Scientist Jerry Prezioso and Megan Switzer next to the CTD and Rosette

Chief Scientist Jerry Prezioso and Megan Switzer next to the CTD and Rosette Photo by: DJ Kast

 

May 21, 14:00 hours: Phytoplankton filtering with Jessica.

In addition to the small bottles Jessica needs, we filled 4 L bottles with water at the 6 different depths (100, 50, 30, 20, 10, 3 m) as well.

We then brought all the 4 L jugs into the chemistry lab to process them. The setup includes water draining through the tubing coming from the 4 L jugs into the filters with the GFFs in it. Each 4 L jug is filtered by 2 of these filter setups preferably at an equal rate. The deepest depth 100 m was finished the quickest because it had the least amount of phytoplankton that would block the GFF and then a second jug was collected to try and increase the concentration of phytoplankton on the GFF.

Phytoplankton filtration setup. Photo by DJ Kast

Phytoplankton filtration setup. Photo by DJ Kast

The filter and pump setup up close. Photo by DJ Kast

The filter and pump setup up close. Photo by DJ Kast

Up close shot of the GFF within the filtration unit.

Up close shot of the GFF within the filtration unit. Photo by DJ Kast

Jessica keeping an eye on her filtration system to make sure nothing is leaking and that there are no air bubbles restricting water flow

Jessica keeping an eye on her filtration system to make sure nothing is leaking and that there are no air bubbles restricting water flow. Photo by DJ Kast

Here I am helping Jessica setup the filtration unit.

Here I am helping Jessica setup the filtration unit.Photo by Jessica Lueders- Dumont

The GFF with the phytoplankton (green stuff) on it.

The GFF with the phytoplankton (green stuff) on it. Photo by: DJ Kast

There are 2 filters for each depth, and since she has 12 filtration bottles total, then she would be collecting data from 6 depths. She collects 2 filters so that she has replicates for each depth.

Here they are all laid out to show the differences in phytoplankton concentration.

The 6 depths worth of GFFs. See how the 30 m is the darkest. Thats evidence for the chlorophyll max. Photo by: DJ Kast

The 6 depths worth of GFFs. See how the 30 m is the darkest. Thats evidence for the chlorophyll max. Photo by: DJ Kast

She will fold the GFF in half in aluminum foil and store it at -80C until back in the lab at Princeton. There, the GFF’s are combusted in an elemental analyzer and the resulting gases run through a mass spectrometer looking for concentrations of N2 and CO2. The 30 m GFF was the most concentrated and that was because of a chlorophyll maximum at this depth.

Chlorophyll maximum layers are common features of vertically stratified water columns. There is a subsurface maximum or layer of chlorophyll concentration. These are found throughout oceans, lakes, and estuaries around the world at varying depths, thicknesses, intensities, composition, and time of year.

Julia West: This Is What Drives Us, April 1, 2015

NOAA Teacher at Sea
Julia West
Aboard NOAA ship Gordon Gunter
March 17 – April 2, 2015

Mission:  Winter Plankton Survey
Geographic area of cruise: Gulf of Mexico
Date: April 1, 2015

Weather Data from the Bridge

Date: 3/31/2015; Time 2000; clouds 25%, cumulus and cirrus; Wind 205° (SSW), 15 knots; waves 1-2 ft; swells 1-2 ft; sea temp 23°C; air temp 23°C

Science and Technology Log

You’re not going to believe what we caught in our neuston net yesterday – a giant squid! We were able to get it on board and it was 23 feet long! Here’s a picture from after we released it:

giand squid

Giant Squid!

April Fools! (sorry, couldn’t resist) The biggest squid we’ve caught are about a half inch long. Image from http://www.factzoo.com/.

Let’s talk about something just as exciting – navigation. I visit the bridge often and find it all very interesting, so I got a 30 minute crash course on navigation. We joked that with 30 minutes of training, yes, we would be crashing!

From the bridge, you can see a long way in any direction. The visible range of a human eye in good conditions is 10 miles. Because the earth is curved, we can’t see that far. There is a cool little formula to figure out how far you can see. You take the square root of your “height of eye” above sea level, and multiply that by 1.17. That gives you the nautical miles that you can see.

So the bridge is 36 feet up. “Really?” I asked Dave. He said, “Here, I’ll show you,” and took out a tape measure.

Dave measuring height

ENS Dave Wang measuring the height of the bridge above sea level.

OK, 36 feet it is, to the rail. Add a couple of feet to get to eye level. 38 feet. Square root of 38 x 1.17, and there we have it: 7.2 nautical miles. That is 8.3 statute miles (the “mile” we are used to using). That’s assuming you are looking at something right at sea level – say, a giant squid at the surface. If something is sticking up from sea level, like a boat, that changes everything. And believe me, there are tables and charts to figure all that out. Last night the bridge watch saw a ship’s light that was 26 miles away! The light on our ship is at 76 feet, so they might have been able to see us as well.

Challenge Yourself

If you can see 7.2 nautical miles in any direction, what is the total area of the field of view? It’s a really amazing number!

Back to navigation

Below are some photos of the navigation charts. They can be zoomed in or out, and the officers use the computer to chart the course. You can see us on the chart – the little green boat.

navigation chart

This is a chart zoomed in. The green boat (center) is us, and the blue line and dot is our heading.

In the chart above, you’ll see that we seem to be off course. Why? Most likely because of that other ship that is headed our direction. We talk to them over the radio to get their intentions, and reroute our course accordingly.

navigation chart 2

Notice the left side, where it says “dump site (discontinued) organochlorine waste. There are a lot of these type dump sites in the Gulf. Just part of the huge impact humans have had on our oceans.

When we get close to a station, as in the first picture above, the bridge watch team sets up a circle with a one mile radius around the location of the station. See the circle, upper center? We need to stay within that circle the whole time we are collecting our samples. With the bongos and the neuston net, the ship is moving slowly, and with the CTD the ship tries maintain a stationary position. However, wind and current can affect the position. These factors are taken into account before we start the station. The officer on the bridge plans out where to start so that we stay within the circle, and our gear that is deployed doesn’t get pushed into or under the boat. It’s really a matter of lining up vectors to figure it all out – math and physics at work. But what is physics but an extension of common sense? Here’s a close-up:

setting up for station

Here is the setup for the station. The plan is that we will be moving south, probably into the wind, during the sampling. See the north-south line?

How do those other ships appear on the chart? This is through input from the AIS (Automated Information System), through which we can know all about other ships. It broadcasts their information over VHF radio waves. We know their name, purpose, size, direction, speed, etc. Using this and the radar system, we can plan which heading to take to give the one-mile distance that is required according to ship rules.

As a backup to the computer navigation system, every half hour, our coordinates are written on the (real paper) navigation chart, by hand.

Pete charting our course

ENS Pete Gleichauf is writing our coordinates on the paper navigation chart.

There are drawers full of charts for everywhere the Gunter travels!

Melissa and the nav charts

ENS Melissa Mathes showing me where all the navigation charts are kept. Remember, these are just backups!

Below is our radar screen. There are 3 other ships on the screen right now. The radar computer tells us the other vessels’ bearing and speed, and how close they will get to us if we both maintain our course and speed.

radar screen

The other vessels in the area, and their bearing, show up on the radar.

If the radar goes down, the officers know how to plot all this on paper.

maneuvering board

On this maneuvering board, officers are trained to plot relative positions just like the radar computer does.

Below is Dave showing me the rudder controls. The rudder is set to correct course automatically. It has a weather adjustment knob on it. If the weather is rough (wind, waves, current), the knob can allow for more rudder correction to stay on course. So when do they touch the wheel? To make big adjustments when at station, or doing course changes.

rudder controls

Dave’s arm – showing me the rudder controls.

These are the propulsion control throttles – one for each propeller. They control the propeller speed (in other words, the ship’s speed).

propeller speed throttles

Here are the throttles that control the engine power, which translates to propeller speed.

bow thruster control

This controls the bow thruster, which is never used except in really tight situations, such as in port. It moves the bow either direction.

And below is the Global Maritime Distress and Safety System (GMDSS). It prints out any nautical distress signal that is happening anywhere in the world!

GMDSS

Global Marine Distress and Safety System

And then, of course, there is a regular computer, which is usually showing the ships stats, and is connected to the network of computers throughout the ship.

checking the weather

ENS Kristin Johns checking the weather system coming our way.

In my post of March 17, I described the gyrocompass. That is what we use to determine direction, and here is a rather non-exciting picture of this very important tool.

gyrocompass

This is the gyrocompass, which uses the rotation of the Earth to determine true north.

As you can see, we have two gyrocompasses, but since knowing our heading is probably the most important thing on the ship, there are backup plans in place. With every watch (every 4 hours), the gyro compass is aligned the magnetic compass to determine our declination from true north. Also, once per trip, the “gyro error” is calculated, using this nifty device:

alidade

This is called the alidade. Using the position of the sun as it rises or sets, the gyro error can be computed and used to keep our heading perfectly accurate.

The reading off of the alidade, combined with the exact time, coordinates, and some fancy math, will determine the gyro error. (Click on a picture to see full captions and full size pictures.)

You can see that we have manual backups for everything having to do with navigation. We won’t get lost, and we’ll always know where we are!

driving the ship

Here I am, “driving” the ship! Watch out! Photo by ENS Pete Gleichauf

Back to Plankton!

These past two days, we have been in transit, so no sampling has been done. But here are a couple more cool micrographs of plankton that Pam shared with me.

invertebrate plankton

This picture shows several invertebrates, along with fish eggs. Madalyn and Andy, who are invertebrate people, got excited at this collection. The fat one, top left is a Doliolid. The U-shaped one is a Lucifer shrimp, the long one in center is an amphipod, at the bottom is a mycid, etc. There are crabs in different stages of development, and the multiple little cylinders are copepods! You can also see the baby fish inside the eggs. Photo credit Pamela Bond/NOAA

red snapper larvae

These are larval red snapper, a fall spawning fish species of economic interest. Notice the scale! You have to admit baby fish are awfully cute. Photo credit: Pamela Bond/NOAA

Interesting Fish Facts

Our main fish of interest in the winter plankton sampling are the groupers. There are two main species: gag groupers and red groupers. You can learn all about them on the NOAA FishWatch Website. Groupers grow slowly and live a long time. Interestingly, some change from female to male after about seven years – they are protogynous hermaphrodites.

red grouper

Red grouper. Image credit: NOAA

In the spring plankton research cruise, which goes out for all of May, the main species of interest is the Atlantic bluefin tuna. This species can reach 13 feet long and 2000 lbs, and females produce 10 million eggs a year!

school of bluefin tuna

School of Atlantic bluefin tuna. Photo credit: NOAA

The fall plankton research focuses on red snapper. These grow up to about 50 pounds and live a long time. You can see from the map of their habitat that it is right along the continental shelf where the sampling stations are.

red snapper

Red snapper in Gray’s Reef National Marine Sanctuary. Image credit: NOAA

The NOAA FishWatch website is a fantastic resource, not only to learn about the biology, but about how they are managed and the history of each fishery. I encourage you to look around. You can see that all three of these fish groups have been overfished, and because of careful management, and research such as what we are doing, the stocks are recovering – still a long way from what they were 50 years ago, but improving.

I had a good question come in: how long before the fish larvae are adults? Well, fish are interesting creatures; they are dependent on the conditions of their environment to grow. Unlike us, fish will grow throughout their life! Have you ever kept goldfish in an aquarium or goldfish bowl? They only grow an inch or two long, right? If you put them in an outdoor pond, you’ll see that they will grow much larger, about six inches! It all depends on the environment (combined with genetics).

“Adult” generally means that they are old enough to reproduce. That will vary by species, but with groupers, it is around 4 years. They spawn in the winter, and will remain larvae for much longer than other fish, because of the cooler water.

Personal Log

I’ve used up my space in this post, and didn’t even get to tell you about our scientists! I will save that for next time. For now, I want to share just a few more pictures of the ship. (Again, click on one to get a slide show.)

 

Terms to Learn

What is the difference between a nautical mile and a statute mile? How about a knot?

Do you know what I mean when I say “invertebrate?” It is an animal without a backbone. Shrimp and crabs, are invertebrates; we are vertebrates!

Julia West: Science Is About the Details, March 29, 2015

NOAA Teacher at Sea
Julia West
Aboard NOAA ship Gordon Gunter
March 17 – April 2, 2015

Mission: Winter Plankton Survey
Geographic area of cruise: Gulf of Mexico
Date: March 29, 2015

Weather Data from the Bridge

Time 1600; clouds 35%, cumulus; wind 170 (S), 18 knots; waves 5-6 ft; sea temp 24°C; air temp 23°C

Science and Technology Log

We have completed our stations in the western Gulf! Now we are steaming back to the east to pick up some stations they had to skip in the last leg of the research cruise, because of bad weather. It’s going to be a rough couple of days back, with a strong south wind, hence the odd course we’re taking (dotted line). Here’s the updated map:

sampling stations 3/29/15

Here’s where we are as of the afternoon of 3/29 (the end of the solid red line. We’ve connected all the dots!

 

I had a question come up: How many types of plankton are there? Well, that depends what you call a “type.” This brings up a discussion on taxonomy and Latin (scientific) names. The scientists on board, especially the invertebrate scientists, often don’t even know the common name for an organism. Scientific names are a common language used everywhere in the world. A brief look into taxonomic categories will help explain. When we are talking about numbers, are we talking the number of families? Genera? Species? Sometimes all that is of interest are the family names, and we don’t need to get more detailed for the purposes of this research. Sometimes specific species are of interest; this is true for fish and invertebrates (shrimp and crabs) that we eat. Suffice it to say, there are many, many types of plankton!

Another question asks what the plankton do at night, without sunlight. Phytoplankton (algae, diatoms, dinoflagellates – think of them like the plants of the sea) are the organisms that need sunlight to grow, and they don’t migrate much. The larval fish are visual feeders. In a previous post I explained that they haven’t developed their lateral line system yet, so they need to see to eat. They will stay where they can see their food. Many zooplankton migrate vertically to feed during the night when it is safer, to avoid predators. There are other reasons for vertical migration, such as metabolic reasons, potential UV light damage, etc.

Vertical migration plays a really important role in nutrient cycling. Zooplankton come up and eat large amounts of food at night, and return to the depths during the day, where they defecate “fecal pellets.” These fecal pellets wouldn’t get to the deep ocean nearly as fast if they weren’t transported by migrating zooplankton. Thus, migration is a very important process in the transport of nutrients to the deep ocean. In fact, one of the most voracious plankton feeders are salps, and we just happened to catch one! Salps will sink 800 meters after feeding at night!

Salp

Salp caught in the neuston sample. Salps are a colony of tunicates (invertebrate chordates for you biology students – more closely related to humans than shrimp are!)

Now it’s time to go back into the dry lab and talk about what happens in there. I’ll start with the chlorophyll analysis. In the last post I described fluorescence as being an indicator of chlorophyll content. What exactly is fluorescence? It is the absorption and subsequent emission of light (usually of a different wavelength) by living or nonliving things. You may have heard the term phosphorescence, or better yet, seen the waves light up with a beautiful mysterious light at night. Fluorescence and phosphorescence are similar, but fluorescence happens simultaneously with the light absorption. If it happens after there is no light input (like at night), it’s called phosphorescence.

phosphorescence

An example of phosphorescence. We haven’t seen it yet, but I hope to! (From eco-adventureholidays.co.uk)

Well, it is not just phytoplankton that fluoresce – other things do also, so to get a more accurate assessment of the amount of phytoplankton, we measure the chlorophyll-a in our niskin bottle samples. Chlorophyll-a is the most abundant type of chlorophyll.

We put the samples in dark bottles. Light allows photosynthesis, and when phytoplankton (or plants) can photosynthesize, they can grow. We don’t want our samples to change after we collect them. For this same reason, we also process the samples in a dark room. I won’t be able to get pictures of the work in action, but here are some photos of where we do this.

chlorophyll lab

This is the room where we do the chlorophyll readings.

We filter the chlorophyll out of the samples using this vacuum filter:

chlorophyll filter

Each of these funnels filters the sea water through a very fine filter paper to capture the chlorophyll.

The filter papers are placed in test tubes with methanol, and refrigerated for 24 hours or so. Then the test tubes are put in a centrifuge to separate the chlorophyll from the filter paper.

filter paper for chlorophyll

Some of the test tubes for chlorophyll readings, and the filter paper. This box costs about $100!

The chlorophyll values are read in this fancy machine. Hopefully the values will be similar to those values obtained during the CTD scan. I’ll describe that next.

Fluorometer

This fluorometer reads chlorophyll levels.

While the nets and CTD are being deployed and recovered, one person in the team is monitoring and controlling the whole event on the computer. I got to be this person a few times, and while you are learning, it is stressful! You don’t want to forget a step. Telling the winch operator to stop the bongos or CTD just above the bottom (and not hit bottom) is challenging, as is capturing the “chlorophyll max” by stopping the CTD at just the right place in the water column.

Bongo graph

This is the graph that comes back from the SeaCAT on the bongo. We are interested in the green line, which shows depth as it goes down and comes back up.

The dry lab

Here I am trying my hand at the computers. The monitor on the left is the live video of what is happening on deck (see the neuston net?). Photo by A.L. VanCampen

 

CTD scan

This is the CTD graph after it has been completed. The left (magenta) line is the chlorophyll, and the horizontal red lines are where we have fired a bottle and collected a sample. Notice the little spike partway down. That is the chlorophyll max, and we try to capture that when bringing it back up. The colored chart shows columns of continuous data coming in.

Here’s another micrograph of larval fish. Notice the tongue fish, the big one on the right. It is a flatfish, related to flounder. See the two eyes on one side of its head? Flatfish lie on the bottom, and have no need for an eye facing the bottom. When they are juveniles, they have an eye on each side, and one of the eyes migrates to the other side, so they have two eyes on one side! Be sure to take the challenge in the caption!

Larval fish 2

There is a cutlass fish just right of center. Can you find the other one? How about the lizard fish? Hint – look back at the picture in the last post. Photo credit Pamela Bond/NOAA

Personal Log

It’s time to introduce our intrepid leader, Commanding Officer Donn Pratt, known as CO around here. CO lives (when not aboard the Gunter) in Bellingham, WA. He got his start in boats as a kid, starting early working on crab boats. He spent 9 years with the US Coast Guard, where he had a variety of assignments. In 2001, CO transferred to NOAA, while simultaneously serving in the US Navy Reserve. CO is not a commissioned NOAA officer; he went about his training in a different way, and is one of two US Merchant Marine Officers in the NOAA fleet. He worked as XO for about seven years on various ships, and last year he became CO of the Gordon Gunter.

CO is well known on the Gunter for having strong opinions, especially about food and music. He loves being captain for fish research, but will not eat fish (nor sweet potatoes for that matter). A common theme of meal conversations is music; CO plays drums and guitar and is a self-described “music snob.” We have fun talking about various bands, new and old.

CO Donn Pratt

CO Don Pratt on the bridge.

One of the most experienced and highly respected of our crew is Jerome Taylor, our Chief Boatswain (pronounced “bosun”). Jerome is the leader of the deck crew. He keeps things running smoothly. As I watch Jerome walk around in his cheerful and hardworking manner, he is always looking, always checking every little thing. Each nut and bolt, each patch of rust that needs attention – Jerome doesn’t miss a thing. He knows this ship inside and out. He is a master of safety. As he teaches the newer guys how to run the winch, his mannerism is one of mutual respect, fun and serious at the same time.

Jerome has been with NOAA for 30 years now, and on the Gunter since NOAA acquired the ship in 1998. He lives right in Pascagoula, MS. I’ve only been here less than two weeks, but I can see what a great leader he is. When I grow up, I want to be like Jerome!

Jerome Taylor

Chief Bosun Jerome Taylor, refusing to look at the camera. No, he’s not grilling steaks; he’s operating the winch!

 

Challenge Yourself!

OK, y’all (yes, I’m in the south), I have a math problem for you! Remember, in the post where I described the bongos, I showed the flowmeter, and described how the volume of water filtered can be calculated? Let’s practice. The volume of water filtered is the area of the opening x the “length” of the stream of water flowing through the bongo.

V = area x length.

Remember how to calculate the area of a circle? I’ll let you review that on your own. The diameter (not radius) of a bongo net is 60 cm. We need the area in square meters, not cm. Can you make the conversion? (Hint: convert the radius to meters before you calculate.)

Now, that flow meter is just a counter that ticks off numbers as it spins. In order to make that a usable number, we need to know how much distance each “click” is. So we have R, the rotor constant. It is .02687m.

R = .02687m

Here’s the formula:

Volume(m3) = Area(m2) x R(Fe – Fs) m

Fe = Ending flowmeter value; Fs = Starting flowmeter value

The right bongo net on one of the stations this morning had a starting flowmeter value of 031002. The ending flowmeter value was 068242.

You take it from here! What is the volume of water that went through the right bongo net this morning? If you get it right, I’ll buy you an ice cream cone next time I see you! 🙂

sunset

Sunset from the Gordon Gunter as we are heading east.