Category: 2008

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Beth Lancaster, April 9, 2008

NOAA Teacher at Sea
Beth Lancaster
Onboard NOAA Ship McArthur II
April 6 – 14, 2008

Mission: Examine the spatial and temporal relationships between zooplankton, top predators, and oceanographic processes
Geographical area of cruise: Cordell Bank Nat’l Marine Sanctuary & Farallones Escarpment, CA
Date: April 9, 2008

Weather Data from the Bridge 
Wind – Northwest 20 – 35 knots
Swell Waves – 4-12 feet
Sea Water Temp – 9.4 – 10.5oC

A 24-hour forecast of sea conditions for April 7, 2008 off the West Coast of the United States. The red section indicates swells that range from 12 to 15 feet.
A 24-hour forecast of sea conditions for April 7, 2008 off the West Coast of the United States. The red section indicates swells 12 to 15 feet.
Reported sea surface temperatures from April 7, 2008 for coastal California from satellite data. The coastal wind did in fact cause an upwelling and cooling of water along the coast. The purple area indicates temperatures 8-8.5oC and the blue 8.6-10oC.
Today’s reported sea surface temperatures for coastal California from satellite data. The coastal wind did in fact cause an upwelling and cooling of water along the coast. The purple area indicates temperatures 8-8.5 degrees C.

The weather reports collected from the bridge of the McARTHUR II reported that the waters traveled over the course of the day did in fact reach 12 feet.  The winds from the northwest cause an upwelling effect, which brings deep, nutrient-rich cooler waters to the continental shelf area off the coast of California. This nutrient-rich water plays a large role in the food web of the area, increasing primary productivity, which will then result in large numbers of marine mammals and birds due to the availability of prey items.  This period of upwelling in the area of Cordell Bank and Gulf of the Farallones National Marine Sanctuaries marks the beginning of a productive time of year.

Science and Technology Log 

Part of the mission on this cruise is to gather oceanographic processes data to look at the relationship between biotic (living) and abiotic (nonliving) factors within the study area.  While many samples are being collected through observation and survey equipment outside of the ship, there is just as much being collected in the laboratory onboard the McArthur II. The ship is equipped with several pieces of equipment that report physical features and measurements throughout the day.  This information is recorded for scientists onboard to utilize in their data analysis.  The following is a list of equipment, and their functions being used to measure oceanic processes:

Thermosalinograph (TSG) – Surface water is pumped from the ocean through a hose to this piece of equipment which measures temperature and salinity.  There is an additional probe that measures CO2. All information collected during the course of the cruise will be given to researchers to use in data analysis.

Scientific Echosounder – Sends a sound wave into the water column.  If there is anything in the water column this sound wave will reflect back to the ship. The longer it takes for the reflected wave to get back to the ship the farther away the target is.  Comparing three different frequencies emitted by the echosounder allow scientists to identify different types of plankton in the water column, and set sampling sites.

Navigation Software – Allows researchers to track where they have been and where they are going. Because nets and other equipment are being deployed from the ship this computer software allows scientists to view the charted underwater topography to determine placement and depth of equipment.  By marking sample sites using the software, scientists can look at the relationship between the ocean’s topography and living organisms collected.

NOAA Teacher at Sea Beth Lancaster (left) and NOAA Chief scientist Dr. Lisa Etherington (right) view sampling areas using navigation software in the McARTHUR II’s dry lab.
NOAA TAS Beth Lancaster (left) and NOAA Chief scientist Dr. Lisa Etherington (right) view sampling areas using navigation software in the McARTHUR II’s dry lab.

Personal Log 

Pteropod collected from a hoop net.
Pteropod collected from a hoop net.

I have been onboard the McARTHUR II for four days, and have enjoyed every minute of helping out with the research project. Scientists have been so patient and willing to answer all of my questions. The crewmembers onboard the McARTHUR II are very friendly and helpful. I now have a much better understanding of the marine physical environment than I did upon my arrival!  I am enjoying living at sea, even the small bunks!  The ship is actually very large you would never know there were more than twenty people onboard!

Animals Seen Today

Black-footed Albatross, Pteropod, Pigeon Guillemot, Copepods, Brandt’s Cormorant,  Ctenophore, Sooty Shearwater, Krill, Northern Fulmar, Microscopic Plankton, Black-legged Kittiwake, California Gull, Western Gull, Common Murre, Cassin’s Auklet, Rhinoceros, Auklet, and Bonaparte’s Gull.

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Beth Lancaster, April 7, 2008

NOAA Teacher at Sea
Beth Lancaster
Onboard NOAA Ship McArthur II
April 6 – 14, 2008

Mission: Examine the spatial and temporal relationships between zooplankton, top predators, and oceanographic processes
Geographical area of cruise: Cordell Bank Nat’l Marine Sanctuary & Farallones Escarpment, CA
Date: April 7, 2008

Beth Lancaster (right) preserves a plankton sample collected using a hoop net.
NOAA Teacher at Sea Beth Lancaster bottles a surface water sample that will be tested for the presence of nutrients.

Science and Technology Log 

Today was the first full daytime operations.  We began shortly after 7:00 a.m., and covered a 90 kilometer transect throughout the course of the day ending at 6:00 p.m.  At each sampling point along the transect a series of measurements and observations were made to look at relationships between the physical ocean environment, and abundance of living organisms that are observed and collected to gain a better understanding of the physical and biological features of the area, and how they interact. The daytime crew was divided into two groups: the marine mammal and bird observers, and a second group that was responsible for collecting water and plankton samples as well as other various physical measurements of the water.  I worked with the second group, and will share what sampling I assisted with.

At each sampling point we used the CTD, which is a piece of equipment that has several probes on it, to collect a vertical sample of the water column.  When the CTD is deployed into the water it is sent down 200 meters below the surface and collects water conductivity (used to calculate salinity), temperature, depth, and turbidity. There is also a fluorometer attached to the CTD that measures the fluorescence of chlorophyll-a, which approximates the abundance of phytoplankton.  The CTD collects all this data, and can then be downloaded onto a computer.  Surface water samples were also collected at each sampling point, and will be tested for the presence of nutrients which would also have a direct impact on the abundance of organisms in the area.

Beth Lancaster (right) preserves a plankton sample collected using a hoop net.
Beth Lancaster (right) preserves a plankton
sample collected using a hoop net.

To gather information on the living organisms present at each site, a hoop net was used to collect samples of plankton.  The net was sent down approximately 50 meters, and collected all of the tiny living organisms (zooplankton) on a screen as the net was pulled through the water column. When the hoop net was brought back onboard, the cod end of the net (where the sample is collected) was transferred to a sample bottle, and preserved for further investigations in the laboratory. In addition to the living organisms collected in the hoop net, marine mammal and bird observations are being made from the flying bridge of the ship. That would be the highest point on the boat, and not the location for people who are afraid of heights. Due to rough sea conditions (10-12 foot swells), sightings were few and far between today.  Springtime within Cordell Bank National Marine Sanctuary is a time where strong winds cause upwelling of deeper waters towards the surface near the coast.  This upwelled water is colder and has higher nutrient concentrations.

Sample of krill caught in the daytime with a hoop net.
Sample of krill caught in the daytime with a hoop net.

This influx in nutrients means the ecosystem becomes very productive. Given this high influx of nutrients, prey items for birds and mammals are readily available. The food of choice for a lot of these organisms is krill (a shrimplike zooplankton.)  We did collect some krill in the hoop net during the day, but the abundance of krill in shallower water is much greater in the evening, when krill migrate from deep depths towards the surface.  The night crew is collecting krill using a tucker trawl, which has three separate nets that are opened and closed at different depths. Krill play a vital role in the ecosystem scientists are currently studying. They provide nourishment for resident and migratory birds as well as marine mammals.  There is sufficient nutrient availability for primary producers which are then food for primary consumers such as krill, and therefore food availability for secondary consumers such as fish and tertiary consumers such as whales and dolphins.

Black-footed Albatross
Black-footed Albatross

Throughout the week the same measurements will be taken at different sights along the continental shelf and continental slope in the region of Cordell Bank National Marine Sanctuary and the Farallones Escarpment (within Gulf of the Farallones National Marine Sanctuary). This information will allow scientists to better understand the dynamic relationship between zooplankton, top predators, and oceanographic processes.  Data gathered will also be used in conservation planning of the marine sanctuaries.

Some Animal Sightings 
Black-footed Albatross, Ancient Murrelet, Northern Fulmar, Laysan Albatross, and Pacific White-sided Dolphin.

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Robert Lovely, April 5, 2008

NOAA Teacher at Sea
Robert Lovely
Onboard NOAA Ship Gordon Gunter
March 31 – April 12, 2008

Mission: Reef Fish Ecological Survey
Geographical area of cruise: Pulley Ridge and the West Florida Shelf, Gulf of Mexico
Date: April 5, 2008

This sea anemone was part of a remarkably diverse community found on Pulley Ridge at a depth of about 212 feet.
This sea anemone was part of a remarkably diverse community on Pulley Ridge at about 212 feet.

Weather Data from the Bridge 
Visibility: 7-8 miles
Wind Direction:  140 degrees (SE)
Wind Speed:  13 knots
Sea Wave Height:  1-2 feet
Swell Wave Height:  2-3 feet
Seawater Temp.: 24.7 degrees C.
Present Weather:  Clear

Science and Technology Log 

Today we made three two-hour ROV dives on Pulley Ridge.  We documented an impressive amount of biodiversity along three transects at depths that ranged from about 190 to 225 feet. Downward still images of the bottom were taken at regular four minute intervals; forward facing still shots were taken whenever something of interest presented itself; and a continuous forward-looking video recording was made of the entire transect.

Agaricia sp., a hermatypic (reef-building) coral we found at about 215 feet.
Agaricia sp., reef-building coral we found at 215 feet.

The ideal cruising speed for the ROV video recording is a very slow one-half knot, which presents significant challenges for the people on the bridge. In fact the Commanding Officer, LCDR Brian Parker, remarked on how good a training exercise this cruise is for his team.  Upon our return to port, and for weeks afterwards, fishery biologist Stacey Harter will analyze the video to derive density estimates for the fishes observed.  She will determine the area covered by each video transect and count individuals of each species that intercepted our transect line.  Abundance estimates then can be extrapolated per unit area.  Others will use similar techniques to determine the aerial extent of living corals.  These data, in turn, will be useful to authorities responsible for managing the fisheries. Pulley Ridge is a drowned barrier island system that formed about 14,000 years ago, when sea levels were lower because a larger portion of the Earth’s water was locked up in glacial ice. While the presence of photosynthetic corals, such as Agaricia spp. was patchy on our dives, we did encounter large fields of green algae in relatively high densities.

The green algae, Anadyomene menziesii, dominated large areas in the southern portion of Pulley Ridge.
The green algae, Anadyomene menziesii, dominated large areas in the southern portion of Pulley Ridge.

This species no doubt is the Anadyomene menziesii described by Robert Halley and his group at the USGS. These striking seascapes resembled large fields of lettuce.  At the southern end of Pulley Ridge this green algae dominated the seabed.  As we moved northward from station to station, however, it occurred in much lower densities, and we began to see higher proportions of the calcareous green algae Halimeda spp. Various species of red coralline algae were also common on Pulley Ridge. Apart from the abundance of Anadyomene menziesii, the other striking observation one makes on this deep coral reef is the presence of conical-shaped mounds and pits.  These structures are almost certainly constructed by fish, such as the sand tilefish (Malacanthus plumieri) and red grouper (Epinephelus morio). Sand tilefish in particular burrow into the coral rubble and pile it up for cover. Red grouper are also industrious excavators.

A red grouper (Epinephelus morio) at rest in a small pit on Pulley Ridge.

A red grouper at rest in a small pit on Pulley Ridge.

The mounds and pits introduce an element of topographic relief into an otherwise flat seascape along the top of Pulley Ridge.  Because so many other species of fish are attracted to these structures, I would suggest that (at least among the fish) sand tilefish and red grouper represent keystone species in this unique ecosystem.  The removal of these two species would have a significant impact on the rest of the community. Other fauna we observed today were typical of what one might encounter on a shallow-water reef, including sponges, tunicates, lobsters, bryozoans, amberjacks, angelfish, reef butterflyfish, snapper, barracuda, and a loggerhead turtle.

Personal Log 

My favorite place on the ship is the boatswain’s chair way up on the bow. No one else seems to know about it, for I have yet to find it occupied when I want to use it.  It is the quietest, most scenic spot on the ship.  Whenever I get a chance, I sneak up there to watch the flying fish. They are flushed by the ship, and some of them can remain in flight for long periods, perhaps 20 seconds or more. If I am especially lucky, I also get to watch dolphins riding our bow. This is a real treat because they seem so playful.

Our ROV disturbs the nap of a loggerhead turtle (Caretta caretta).
Our ROV disturbs the nap of a loggerhead turtle (Caretta caretta).
A pod of dolphins bow-riding the GORDON GUNTER.
A pod of dolphins bow-riding the ship. 
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Robert Lovely, April 4, 2008

NOAA Teacher at Sea
Robert Lovely
Onboard NOAA Ship Gordon Gunter
March 31 – April 12, 2008

Mission: Reef Fish Ecological Survey
Geographical area of cruise: Pulley Ridge and the West Florida Shelf, Gulf of Mexico
Date: April 4, 2008

A “rosette” is used to hold the instrumentation for the CTD. Here we see the rosette being lowered down into the water column by way of a crane mounted on the GORDON GUNTER.
A “rosette” is used to hold the instrumentation for the CTD. Here it is lowered down into the water by way of a crane.

Weather Data from the Bridge 
Visibility:  12 miles
Wind Direction:  150° (SE)
Wind Speed:  18 knots
Sea Wave Height:  2-3 foot
Swell Wave Height:  1-2 foot
Seawater Temp: 24.4 degrees C.
Present Weather:  Clear

Science and Technology Log 

We begin and end each day by making a CTD profile of the water column at our sampling site.  CTD refers to conductivity, temperature, and depth, but other parameters, such as dissolved oxygen (DO), also may be measured.  Conductivity is an expression of salinity, which at our location on Pulley Ridge is pretty uniform throughout the water column.  As we see from the graph below, however, both DO and water temperature do vary with depth. Temperature is uniform in the top layer of water and then begins to drop steadily with increasing depth from about 20 meters down.  This portion of the water column, where temperature declines rapidly with depth, is called the thermocline.  The temperature profile on our graph shows that a subtle thermocline extends nearly to the bottom at Pulley Ridge. This may help explain why certain shallow-water organisms are able to survive in this relatively deep water. In other locations the same depth may be well below the thermocline and therefore in water too cold for shallow-water species to live.

Above is a graph of the CTD profiles generated at Pulley Ridge on April 4, 2008. Software linked to the CTD instrumentation on the rosette generates salinity, temperature, depth and oxygen profiles of the water column. Note that the double lines on the graph result from the roundtrip made by the rosette down to the bottom and back.
Graph of the CTD profiles from Pulley Ridge. Software linked to the CTD instrumentation on the rosette generates salinity, temperature, depth and oxygen profiles of the water. The double lines on the graph result from the roundtrip down to the bottom and back.

Dissolved oxygen is normally high at the surface due to the mixing effect of wave action. But oxygen concentrations can be high in the deeper thermocline as well simply because cold water can hold more oxygen than warm water.  Our graph above illustrates this relationship by exhibiting an increase in dissolved oxygen concentrations at depths between 20-45 meters.

This remotely operated vehicle (ROV) carries both a video camera and a still camera. The yellow umbilical shown in the foreground supplies power and control signals from the GORDON GUNTER.
This remotely operated vehicle (ROV) carries both a video camera and a still camera. The yellow umbilical shown in the foreground supplies power and control signals

Marine scientists employ different types of underwater vehicles to collect data on deep coral reefs, and the different vehicle types may seem a bit confusing at first.  Three important underwater vehicles are Submersibles, AUVs, and ROVs.  Submersibles typically refer to human-occupied vehicles, where a pilot climbs inside and drives the vehicle around like a small submarine.  The most famous example is Alvin, a submarine operated by the Woods Hole Oceanographic Institution. AUVs, in contrast, are Autonomous Underwater Vehicles that are programmed to perform specific functions, such as bathymetric mapping.  AUVs are robotic— they are completely independent, having no wires to the surface.  Finally, ROVs are Remotely Operated Vehicles, which are tethered to the ship by means of a cable and umbilical.  The ROV captures video and still images, and is driven by a pilot from a control room onboard the ship.  While utilizing bathymetric charts created during earlier cruises, our mission on Pulley Ridge and the West Florida Shelf employs only the ROV.

Rob finds out that it’s interesting, but difficult, driving the ROV.
Rob finds out that it’s interesting, but difficult, driving the ROV.

Today we made three video transects (dives) with the ROV, each lasting about two hours.  Each dive followed a predetermined course, as we began working our way north along Pulley Ridge.  The depth of our dives normally ranged between 200-230 feet, with the ROV gliding about three feet above the reef. The ship towed the ROV at speeds that typically ranged from .5 to 1.3 knots.  However, because of the slack in the tether, the ROV itself had a remarkable range of speeds. In fact, skilled pilots can bring the ROV to a dead stop (while the ship continues to move) in order to pause for nice steady close-up shots of bottom organisms.  I was very impressed by this flexibility of motion and the freedom it offered the pilot to search around the reef for organisms hiding in nooks and crannies.

Personal Log 

I was given the opportunity to take the helm of the ROV during one of our video transects. I found this experience to be fun and somewhat akin to playing a video game.  However, I also found driving the ROV to be much more difficult than it looks.  It gave me a greater appreciation for the skill of our veteran pilots, Lance Horn and Glenn Taylor. 

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Robert Lovely, April 2, 2008

NOAA Teacher at Sea
Robert Lovely
Onboard NOAA Ship Gordon Gunter
March 31 – April 12, 2008

Mission: Reef Fish Ecological Survey
Geographical area of cruise: Pulley Ridge and the West Florida Shelf, Gulf of Mexico
Date: April 2, 2008

NOAA ship GORDON GUNTER at the dock in its home port of Pascagoula, MS.
NOAA ship GORDON GUNTER at the dock in its home port of Pascagoula, MS.

Weather Data from the Bridge 
Visibility:  10-12 miles
Wind Direction:  East (080)
Wind Speed:  10 knots
Sea Wave Height:  1-2 foot
Swell Wave Height:  1-2 foot
Seawater Temperature: 23.93 C.
Present Weather Conditions:  Partly cloudy

Science and Technology Log 

After spinning around in circles in the harbor area so that a specialist could synchronize all the compasses onboard the ship, we left the Port of Pascagoula at about 10 a.m. on Monday, March 31. We would have two full days and nights of transit to our first station at Pulley Ridge, which lies about 54 nautical miles west of the Dry Tortugas (see map above).  The weather was cold, cloudy, and windy on the first day, and the waves ranged from four to six feet high.  This set the stage for a very rocky first day at sea. On day two, however, the seas flattened out, and the weather was beautiful, with a clear blue sky and only light winds. I could see for miles in every direction, but there was no land in sight. 

Southern Florida
Southern Florida

One of the main objectives of our mission is to identify the extent of live stony corals (order: scleractinia) on Pulley Ridge.  This approximately 20-mile long three-mile wide undersea ridge has been designated as a habitat area of particular concern, and consequently carries certain fishing restrictions.  Trawling gear, in particular, may not be used.  Moreover, fishers are not allowed to drop anchor, use long lines, bottom traps and other equipment that is apt to kill or damage the coral. Because the corals serve as prime breeding habitat for many commercially-important species of fish, it is in the long-term interest of the commercial fisheries to protect areas such as Pulley Ridge. Apart from its importance as fish habitat, though, Pulley Ridge also is unique because it contains the deepest known photosynthetic coral reefs on the U.S. continental shelf.  Scleractinian corals, such as Agaricia spp., thrive along with sponges and common species of reef algae in water some 250-feet deep.

Pulley Ridge dive sites. The red dots indicate start and stop points for individual dive transects. Map by Marta Ribera.
Pulley Ridge dive sites. The red dots indicate start and stop points for individual dive transects.

Because the Pulley Ridge reefs lie well below the safe-diving limit of 130 feet, the most practical and efficient way to explore these unique habitats is by means of a remotely-operated vehicle (ROV) equipped with digital still and video cameras.  When deployed, the ROV is tethered to the ship by means of a long umbilical and driven by an operator in the control room.  The umbilical delivers electric power and control signals to the ROV. From the control room the ROV pilot watches a video monitor and steers the unit much like one would play a video game.  Video of the sea bottom is recorded continuously, while high resolution digital still frames are recorded at specific time intervals, such as every two minutes.  The scientific field party on this mission consists of six individuals, two of whom are dedicated to the operation and maintenance of the ROV.  The rest are biologists.  The ship itself carries a crew of 18. Long before we left port, Andrew David, the chief scientist, developed a cruise plan, which called for the ROV to make dives along specific transects. We reached our station for the first transect at about 7:30 this morning.

ROV team Lance Horn (left) and Glenn Taylor prepare the ROV for deployment.
ROV team Lance Horn and Glenn Taylor prepare the ROV for deployment.

After considerable setup, the ROV was deployed and lowered down to the bottom, about 300 feet below the surface.  ROV pilot Lance Horn drove the unit about a meter or two above the bottom, recording video continuously and taking digital still images at two-minute intervals.  Biologist Stacey Harter added narration to the video by identifying the different fishes and bottom conditions she saw on the monitors. Everything ran quite smoothly for the first half of the transect. But then the video light flooded and popped a breaker, causing the ROV to lose power. The unit had to be brought back onboard the ship for repairs.  That was it for the day. “The deep sea bottom is such an extreme environment,” said Andrew David, “that equipment break-downs like today’s are practically a routine part of doing science at sea.”

Personal Log 

While watching today’s operations, I couldn’t help but think how easy I have it when I take a class of students out onto Wisconsin lakes to do basic limnology.  We work from a small, easyto-maneuver pontoon boat.  None of our equipment is too heavy for a student to lift over the side and drop in. Our depths rarely exceed 20 meters.  Finally, we collect a considerable amount of data in just a three-hour lab period.

Chief scientist Andrew David feeds out the ROV’s umbilical during deployment.
Chief scientist Andrew David feeds out the ROV’s umbilical during deployment.
The ROV is lowered into the water.
The ROV is lowered into the water.
The ship’s dry lab serves as a control room for the ROV. From left to right: Marta Ribera (GIS specialist), ROV pilot Lance Horn, and Stacey Harter (fish biologist).
The ship’s dry lab serves as a control room for the ROV. From left to right: Marta Ribera (GIS specialist), ROV pilot Lance Horn, and Stacey Harter (fish biologist).