Mary Anne Pella-Donnelly, September 15, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 15, 2008

Weather Data from the Bridge 
Latitude: 3720.718 N Longitude: 12230.301
Wind Direction: 69 (compass reading) NW
Wind Speed: 12.0 knots
Surface Temperature: 15.056

Computer generated images showing acoustic scattering during the day
Computer generated images showing acoustic scattering during the day

Science and Technology Log 

A lot of physical science is involved in oceanographic research.  An understanding of wave mechanics is utilized to obtain sonar readings. This means that sound waves of certain frequencies are emitted from a source.  The concepts to understand in order to utilize acoustic readings are:

  1. Sound and electromagnetic waves travel in a straight line from their source and are reflected when they contact an object they cannot pass through.
  2. Frequency is defined as the number of waves that pass a given point per second (or another set period of time).  The faster the wave travels, the greater the number of waves that go past a point in that time. Waves with a high frequency are moving faster than those with a low frequency. Those waves travel out in a straight line until they contact an object of a density that causes them to reflect back.
  3. The speed with which the waves return, along with the wavelength they were sent at, gives a ‘shadow’ of how dense the object is that reflected the wave, and gives an indication of the distance that object is from the wave source (echo sounder). As jellyfish, zooplankton and other organisms are brought up either with the bongo net or the trawl net, examinations of the acoustic readings are done to begin to match the readings with organisms in the area at the time of the readings.  On the first leg of the survey, there were acoustic patterns that appeared to match conditions that are known to be favorable to jellyfish.  Turtle researchers have, for years, observed certain characteristics of stretches of ocean water that have been associated with sea nettle, ocean sunfish and leatherbacks. Now, by combining acoustic readings, salinity, temperature and chlorophyll measurements, scientists can determine what the exact oceanographic features are that make up ‘turtle water’.
Computer generated images showing acoustic scattering at night.
Computer images of acoustic scattering at night.

Acoustic data, consisting of the returns of pulses of sound from targets in the water column, is now used routinely to determine fish distribution and abundance, for commercial fishing and scientific research. This type of data has begun to be used to quantify the biomass and distribution of zooplankton and micronekton. Sound waves are continuously emitted from the ship down to the ocean floor. Four frequencies of waves are transmitted from the echo-sounder.  The data is retrieved and converted into computerized images. Both photo 1 and photo 2 give the acoustic readings. The “Y” axis is depth down to different depths, depending on the location.  The frequencies shown are as follows for the four charts on the computer screen; top left is 38kHz, bottom left is 70 kHz, top right is 120kHz and bottom right is 200 kHz.  In general the higher frequencies will pick up the smallest particles (organisms) while the lowest reflect off the largest objects. Photo 1 shows a deep-water set of images, with small organisms near the surface. This matches the fact that zooplankton rise close to the surface at night.  Photo 2 gives a daylight reading.

A Leach’s storm petrel rests on the trawl net container.
A Leach’s storm petrel rests on the trawl net container.

It is more difficult to interpret.  The upper one-fourth is the acoustic reading and the first distinct horizontal line from the top represents the ocean floor.  Images below that line are the result of the waves bouncing back and forth, giving a shadow reading.  But the team here was very excited: for this set of images shows an abundance of organisms very near the surface. And the trawl that was deployed at that time resulted in lots and lots of jellyfish.  They matched.  Periodically, as the acoustic data is collected, samples are also collected at various depths to ‘ground truth’ the readings.  This also allows the scientists to refine their interpretations of the measurements.  The technology now can give estimates of size, movement and acoustic properties of individual planktonic organisms, along with those of fish and marine mammals.  Acoustic data is used to map the distribution of jellyfish and estimate the abundance in this region. By examining many acoustic readings and jellyfish netted, the scientists will be able to identify the acoustic pattern from jellyfish.

Karin releases a petrel from nets he flew into.
Karin releases a petrel from nets he flew into.

The sensor for the acoustic equipment is mounted into the hull, with readings taken continually.  Background noise from the ship must be accounted for, along with other types of background noise. Some events observed on board, such as a school of dolphins being sighted, can be correlated (matched) to acoustic readings aboard the ship.  Since it is assumed that only a portion of the dolphins in a pod are actually sighted, with the remaining under the surface, the acoustic correlation gives an indication of population size in the pod.  The goal of continued acoustic analysis is to be able to monitor long term changes in zooplankton or micronekton biomass. This monitoring can then lead to understanding the migration, feeding strategies and monitor changes in populations of marine species.

A Wilson’s warbler rests on the flying deck.
A Wilson’s warbler rests on the flying deck.

Personal Log 

Several small birds have stopped in over the week, taking refuge on the Jordan. Many bird species make long migrations, often at high altitude, along the Pacific flyway.  Some will die of exhaustion along the way, or starvation, and some get blown off their original course.  Most ships out at sea appear to be an island, a refuge for tired birds to land on.  They may stay for a day, a week, or longer. Their preferred food source may not be available however, and some do not survive on board.  Some die because they are just too tired, or perhaps ill, or for unknown reasons. We have had a few birds, and some have disappeared after two days.  We hope they took off to finish their trip. Since we were in site of land all day today, it could be the dark junco headed to shore. ‘Our’ common redpoll did not survive, so he was ‘buried at sea’, with a little ceremony.  About half an hour ago, a stormy petrel came aboard.  He did not seem well, but after a bit of rest, we watched him take off.  We wish him well.

Words of the Day 

Acoustic data: sound waves (sonar) of certain frequencies that are sent out and bounce off objects, with the speed of return an indication of the objects distance from the origin; Echo sounder: device that emits sonar or acoustic waves Dense or density: how highly packed an object is  measured as mass/volume; Distribution: the number and kind of organisms in an area; Biomass:  the combined mass of a sample of living organisms; Micronekton: free swimming small organisms; Zooplankton: small organisms that move with the current; Pacific flyway: a general area over and next to the Pacific ocean that some species of birds migrate along.

Animals Seen Today 
Leach’s Storm-petrel Oceanodroma leucorhoa
Herring gull Larus argentatus
Heermann’s gull  Larus heermanni
Common murr  Uria aalge
Humpback whale  Megapterea novaeangliae
California sea lion Zalophus californianus
Sooty shearwater Puffinus griseus
Brown pelican Pelecanus occidentalis
Harbor seal Phoca vitulina
Sea nettle jellies Chrysaora fuscescens
Moon jellies Aurelia aurita
Egg yolk jellies Phacellophora camtschatica 

Questions of the Day 
Try this experiment to test sound waves.  Get two bricks or two, 4 inch pieces of 2 x 4 wood blocks. Stand 50 ft opposite a classroom wall, and clap the boards together. Have others stand at the wall so they can see when you clap. Listen for an echo.  Keep moving away and periodically clap again. At some distance, the sound of the clap will hit their ears after you actually finish clapping. With enough distance, the clap will actually be heard after your hands have been brought back out after coming together.

  1. Can you calculate the speed of the sound wave that you generated?
  2. Under what conditions might that speed be changed?
  3. Would weather conditions, which might change the amount of moisture in the air, change the speed? 

Mary Anne Pella-Donnelly, September 13, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 13, 2008

Weather Data from the Bridge 
Latitude: 3645.9407 N Longitude: 12501.4783 W
Wind Direction: 344(compass reading) NE
Wind Speed: 13.5 knots
Surface Temperature: 14.197

Computer generated map of sampling area using satellite and in situ data. The satellite image on the right includes land (white) on the right edge, of the area between San Francisco and San Luis Obispo.
Computer generated map of sampling area using satellite and in situ data. The satellite image on the right includes land (white) on the right edge, of the area between San Francisco and San Luis Obispo.

Science and Technology Log 

As the scientific team conducts its research locating areas where jellyfish congregate, they have determined that samples need to be taken along both sides of a warm water/cold water boundary.  The charts below comprise a computer-generated chart of water temperature in the area we are focusing on. The chart on the right was created from remotely sensed data obtained from a satellite, and a small square of that is enlarged on the left. The chart on the left is produced from a computer model that smoothes out the lines and includes data taken continuously from the ship and integrated into the chart. Although hard to read at this resolution, the legend shows where CTD’s have been deployed, along with XBT’s, which record temperature. It also marks where upcoming deployments will take place. Net trawls were also deployed to collect samples of jellyfish that might be in the region. The quest is on for good turtle habitat.

After examining these charts above, please answer the following questions:

  1. What can you tell about the temperature of the water just off the coastline for most of that area of California?
  2. What range temperature of water does it appear that the LUTH survey is currently sampling in?
  3. Would you expect to find the same organisms in each of the samples? Why or why not?
  4. What might cause temperatures to be different in some parts of the ocean?

The Expendable Bathy Thermograph (XBT), consists of a long copper wire shot into the water down to 760 m.  When kept in the water for 2 minutes, the cable registers a signal to a dedicated computer, giving temperature readings along the wire, which are immediately plotted onto a graph.

After looking at this graph, answer the following questions:

  1. What temperature is measured at the surface?
  2. At what depth below the surface does the temperature start to drop dramatically? How many degrees Celsius is the drop?
  3. How many more degrees does the temperature drop, after the initial quick decrease? In how many meters does this gradual drop occur?

The LUTH survey is very interested in finding out whether jellyfish are found in the colder water (yellow and green), and how the distribution changes through the changing temperature of the water. Their questions surround what conditions would allow leatherbacks to travel along certain routes to and from the California coast, and how to identify areas of productivity so that commercial fishing can occur without harming protected species. Every jellyfish caught, either by the net trawls or the bongo net, and oceanographic data collected at the same time, provides more insight into where favorable conditions might exist.

Personal Log 

Computer generated graph of XBT data from 8/28/08 at 18:15:30 (6:15 pm)
Computer generated graph of XBT data from 8/28/08 at 18:15:30 (6:15 pm)

It is a very different lifestyle to have a profession that involves living for periods of time aboard a ship. Most of us land-based folks get up, wander through the house, eventually rounding up food and heading off to school or work.  For me, after a day full of movement all over Chico Junior High’s large school grounds, I may go to the store, run errands and then return home to read the paper, clean house, and prepare dinner.  My family will eventually arrive home and we will go over the day’s events.  Here, the crew spends up to 23 days in this home, office and recreational area, away from their families.  Two cooks prepare, serve buffet-style and clean up after all meals; serving at 7am, 11am and 5pm.  During off hours, I have observed T.V. or movie watching, card games in action and some gym use.

Many people have iPods and in some areas music is broadcast. Personal computers with satellite internet capabilities are used, I assume, to communicate with friends and family on land.  It is interesting that the ‘living room’, which is also the mess hall, may have 10 colleagues in it sometimes watching a show. I am used to cooking when I choose, or just making cookies if I want or heading outside to jog with my dog after school. No such activities like that happen here.  Every one in the crew seems to get along, is extremely polite to each other, and is also very pleasant.  It takes a very flexible person to enjoy living on a ship and a certainly love for the ocean.  I am enjoying this very different way of living, and will also enjoy when I can run a few miles through the park again.

Animals Seen Today 
Sea nettle jellies Chrysaora fuscescens
Comb jellies Kiyohimea spp.
Sea gooseberry Pleurobrachia bachei
Common dolphins Delphinus delphis
Jack mackerel Trachurus symmetricus
Wilson’s warbler Wilsonia citrine
Yellow-rumped warbler Dendroica coronata 

Questions for the Day 
1. What part of your regular pattern would be easiest to give up, if you were to live aboard a ship?  Which parts would be hardest?

Mary Anne Pella-Donnelly, September 11, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 11, 2008

Weather Data from the Bridge 
Latitude: 3647.6130W Longitude: 12353.1622 N
Wind Direction: 56 (compass reading) NE
Wind Speed: 25.7 knots
Surface Temperature: 15.295

Bongo net being deployed to collect specimens
Bongo net being deployed to collect specimens

Science and Technology Log 

One oceanographic phenomena of interest is the deep scattering layer (DSL). This is a zooplankton and micronekton rich layer that is found below the depth that light penetrates to in the daytime. After sunset, this DSL layer migrates up closer to the surface.  In some locations the daytime DSL may be at a depth of 225-250 m depth in this area of the California current ecosystem, and 0-100 m during the night. It is hypothesized that the organisms stay deeper down during the daytime to avoid predation, and move up toward the surface at night when it is safer from predators.  Oceanographers take advantage of this information. Every evening, two hours after sunset, bongo nets are deployed to a depth of 200m and then slowly brought to the surface to get a sample of the entire water column.  The purpose is to collect samples of those organisms that are found in the DSL. During the day these organisms would be much deeper down below the surface, but at night they are much closer.

Chart that converts wire length and angle to depth
Chart that converts wire length and angle to depth

The process begins with opening up the large plankton nets and attaching a weight in between the loops of the frame.  The frame is hooked to a cable that is maneuvered by a winch operator.  After the bongo net is swung out from the ship, a large protractor, an inclinometer, is attached. This is used to give the Officer of the Deck (OOD) driving on the bridge an indication of speed needed to deploy the net at. The OOD adjusts the speed of the ship to maintain the required angle, which allows the net to remain open for collection and reach the desired depth. Looking at the chart above, you can see that the angle the wire is deployed at, along with the amount of wire paid out, can be converted to a given depth. Trigonometry at work. There is also a flow meter attached inside each of the bongo loops. The readings from this give an indication of the volume of water that passed through the nets. When the bongo is retrieved, before the end is detached, each net is rinsed with salt water from a hose in order to retrieve as much of the sample as possible in the cod end. This end is detached and brought into the lab.  One of the samples is examined in the lab, for relative types, while the other sample is preserved in formaldehyde and sodium borate for later examination and identification.

Stateroom on the Jordan
Stateroom on the Jordan

Personal Log 

It is very interesting being rocked to sleep each night.  Being on the top bunk, I am about 2 feet from the ceiling, with several pipes suspended from the ceiling.  Once settled in bed, there is little opportunity to move around much.  But being slowly rocked from side to side is a very interesting sensation, and is relaxing.  It is becoming easier to tell how calm the water is that the ship is moving through, or a little about the weather, since sometimes we rock up and down, instead of from side to side. We were told that when it gets really rough it is a good idea to place a life jacket under the edge of the mattress to keep us from falling out.  Each bed has a dark curtain edging it, since many of the crew and scientists may have opposite shifts. Since there is no porthole in my stateroom, when the lights are out and the curtain is closed, it is very dark. It would be impossible to tell night from day, except by an internal clock or a timepiece.  It has been comfortable sleeping.  Getting up is the only difficult part, maneuvering in the small space of the bunk and being careful not to disturb my bunkmate, Liz.  Her schedule varies from mine, due to her bongo net responsibilities and CTD expertise.  So far the sleeping arrangement has worked out well.

Words of the Day 

 Stateroom dresser aboard the Jordan
Stateroom dresser aboard the Jordan

Distribution: the local species and numbers of organisms in an area; Biomass: the combined mass of a sample of living organisms; Micronekton: free swimming small organisms; Zooplankton: small organisms that move with the current; Predation: the process of organisms eating other organisms to survive; Inclinometer: protractor designed to measure altitude from the horizon.

Questions of the Day 

  1. What organisms do you know of that change their feeding strategy at different times of the day?
  2. In the local creek, river, or lake near you, are there both micronekton and zooplankton?  How could you find out?

Mary Anne Pella-Donnelly, September 10, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 10, 2008

Weather Data from the Bridge 
Latitude: 3736.6398 N Longitude: 12336.2210 W
Wind Direction: 220 (compass reading) SW
Wind Speed: 11.3 knots
Surface Temperature: 14.638

This moon jelly was captured with the mid-water net.  Its bell was 35.5 cm wide.   The purplish pattern represents the gonads, which the turtles love to eat.
This moon jelly was captured with the mid-water net. Its bell was 35.5 cm wide. The purplish pattern represents the gonads, which the turtles love to eat.

Science and Technology Log

The mid-water net was just deployed.  This is a new net for the research team to use.  On the trip north, during the first part of this cruise, the last net became mangled during use.  A new, larger net was obtained and the crew is working out how best to deploy it.  After three tries, they seem to have determined the best way to lay it out, release it, and winch it back in. The David Starr Jordan is now heading over to the off shore area outside of Point Reyes, where the plan will be to deploy it for only one to two minutes.

The jellyfish there are usually so numerous that they will fill the net immediately.  Leatherbacks eat jellyfish of many kinds, but they love the types in the Pelagiidae family.  These are the types with long hanging arms, which the turtles snack on until they get up into the body cavity. The jellyfish are then eaten from the insides, with a soft-bodied bell left behind. The bell-shaped body of this family can be as large as 55 cm.    The favorite of leatherback, so the one we will hope to find in abundance, is the Sea nettle, Chrysaora fuscescens. These are most numerous in August and September in specific locations off the California coast, so it can be anticipated that leatherbacks will also be found there.  The predictability of this occurrence is the reason leatherbacks have evolved to travel the Pacific Ocean from Asia every year. 

Unidentified songbird, hopping a ride aboard the Jordan.
Unidentified songbird, hopping a ride aboard the Jordan.

The ship, David Starr Jordan, was built in 1965, so is among the oldest of the fleet of NOAA research ships.  The age can be found in the cabinet design, the flooring material and little features. Never the less, it has been built for sustained trips at sea for up to 23 days in length. There is a steward on board who creates elaborate lunches and dinners daily. Last night’s dinner included Filet Mignon, shrimp in butter sauce, two soups, sautéed vegetables, and at least four other hot dishes. There is always a salad bar set up and 24-hour hot beverages, cereal, toast, ice cream, yogurts and fruit. Everyone eats well.

In the crew’s lounge, drawers of over 200 current films are stored, including new releases. They have been converted to 8 mm tape to accommodate the video system on board.  There is also a small gym with a treadmill, stationary bicycle and bow-flex machine.  A laundry room completes the ‘home’ environment. At least three showers are available.  The ship has a system to desalinate water, which is a slow process, so water conservation is suggested.  This means:  wet yourself down, turn off the water, soap up and scrub, then turn the water on and rinse off.  Repeat if necessary. There are no water police, but we all have an interest in enough water being available.

Although the food has looked great, I have found that until I get my ‘sea legs’ I need to stay away from most food.  Yesterday evening, I discovered that the lunch and dinner I ate; did not look as good coming out as it did going down.  Today is better, but I will stick to yogurt, oatmeal, and tea for a bit.

Animals Sighted Today 
Sea nettle jellies Chrysaora fuscescens
Moon jellies Aurelia aurita
Egg yolk jellies Phacellophora camtschatica
Ocean sunfish Mole mole
Humpback whale Megapterea novaeangliae
Blue whale Balaenoptera musculus
Common murre Uria aalge
Black phoebe Sayornis nigricans
Red phalarope Phalaropus fulicaria
Buller’s shearwater Puffinus bulleri
Sooty shearwater Puffinus griseus
Brown pelican Pelecanus occidentalis
Brandt’s cormorant Phalacrocorax penicillatus
Dall’s porpoise Phocoenoides dalli 

Questions of the Day 

  1. What type of data is considered ‘oceanographic’ data?
  2. What types of organisms produce chlorophyll in the ocean?

Mary Anne Pella-Donnelly, September 10, 2008

NOAA Teacher at Sea
Mary Anne Pella-Donnelly
Onboard NOAA Ship David Jordan Starr
September 8-22, 2008

Mission: Leatherback Use of Temperate Habitats (LUTH) Survey
Geographical Area: Pacific Ocean –San Francisco to San Diego
Date: September 10, 2008

Weather Data from the Bridge 
Latitude: 3737.3158 N Longitude: 12337.1670 W
Wind Direction: 234 (compass reading) SW
Wind Speed: 9.7 knots
Surface Temperature: 14.638

Deck crew setting up the mid-water net to be deployed off the back deck.
Deck crew setting up the mid-water net to be deployed off the back deck.

Science and Technology Log 

Two consistent methods of data collection on the survey include netting and collecting oceanographic data. Up to three times a day a mid-water net is carefully dropped off the back, and towed at the surface. The last two times the net has been pulled in one or two moon jellies have been caught. Each specimen is weighed and measured, then tossed back. Every evening, two hours after sunset, a bongo net is deployed off the side of the boat. With weights added, it is designed to drop as far as 300 m below the surface. Since there are two nets collecting, the scientists are able to retrieve and preserve the contents of one, to be analyzed for species composition later, and examine the second here on the boat.  This is done two hours after sunset since many organisms come much closer to the surface after dark, when their predators are less likely to find them.

Another important tool that is used to collect oceanographic data is the CTD.  This CTD has eight chambers and can collect samples from eight different water depths.  It is carefully dropped down to 500 m (or more if needed), and then a chamber is opened at intervals determined by the scientist collecting the samples. Every waking hour the temperature of the ocean is sampled using a XBT “gun” that shoots out a 760 meter long copper wire. XBT stands for Expendable Bathy thermograph. The weighted wire is kept in the ocean until a stable reading is obtained.  This gives an indication of the temperature gradient from the surface down to 760 meters in the immediate area. 

Personal Log 

Two Dall’s porpoise gliding next to the ship.
Two Dall’s porpoise gliding next to the ship.

The first 24 hours were smooth sailing through overcast but calm seas.  We have had two visits by common dolphins who have seen the boat, told their 4 or 5 best buddies, and come over to ‘ride the bow.’ They glide under the surface, leap up through the waves and glide some more.  They are having a blast. The second time was less convenient for the research, since the mid-water net could not be deployed with marine mammals in the area. And the dolphins wouldn’t leave!! So deployments had to wait 45 minutes for the dolphins to get tired and go find another playground. Yesterday a net drop deployment was almost postponed again, for a large pod of white-sided dolphins spotted behind the boat. They swam perpendicular to the ship however, and stayed a good distance away. It was estimated that there were

180 of them! That was it for yesterday. The first afternoon, we saw one humpback whale spouting and then it showed its fluke as it went under.  Another four were seen in the distance. We are all looking forward to more sightings.  The primary job that I and another ship visitor have, is to act as observers up on the flying bridge, one half hour before the net is scheduled to be dropped, and stay until the net is retrieved.  Because of the Marine Mammal Protection Act, all activity that could put these animals at risk must not be done if any marine mammals are in the area. So I sit up on the highest deck, and watch.  There is a walkie-talkie next to me, a computer set to log any sightings of interest, including jellies that float by and high-powered binoculars to scan the surface.  With snacks and beverages always handy in the mess hall, I can be quite cozy.

Animals Seen So Far 
Humpback whale Megapterea novaeangliae
Common dolphin Delphinus delphis
Pacific white-sided dolphin Lagenorhynchus olbiquidens
California Sea lion Zalophus californianus
Moon jelly Aurelia labiata
Egg yolk jelly Phacellophora camtschatica
Sooty shearwater Puffinus griseus
Buller’s Shearwater Puffinus bulleri  

We also have a few lost, confused song birds on board-who are happily eating up insects for us Western tanager Piranga ludoviciana Townsend’s warbler Dendroica townsendi 

Questions of the Day 

  1. What is the purpose of scientific names in international research?
  2. To become a marine scientist, what fields of science are required as background?