NOAA Teacher at Sea
Tiffany Risch
Onboard NOAA Ship Delaware II July 28 – August 8, 2008
Mission: Clam and Quahog Survey Geographical Area: South of Long Island, NY Date: August 5, 2008
Tiffany uses a measuring board to obtain quahog lengths.
Weather Data from the Bridge
Partly to mostly cloudy, with patchy a.m. fog
Surface winds: West-Northwest 10-15 knots
Waves: Swells 3-5 feet
Water temperature: 16o Celsius
Visibility: 7 nautical miles
Science and Technology Log
We’ve almost completed the entire research cruise here on the DELAWARE II. With a few more stations to cover, it is amazing how so many clams can be processed in only a week and a half at sea. Here on the DELAWARE II, scientists use digital recording devices such as scales and measuring boards to obtain accurate records. They also use computer programs that are specialized for the research being done.
When a tow is completed and the catch sorted, each surf clam or quahog goes through a series of measurements. Each bushel of clams is massed, and then each one is digitally measured. With sometimes over 2,000 clams to process, this technique is helpful because we can complete a station in as little as 30 minutes. The computer program used for this purpose asks the measurer to select the species, and then it automatically records whatever the clam measures width wise on the measuring board.
There are only about twelve stations left to go before we arrive in Woods Hole, Massachusetts. Most stations turn up a moderate number of surf clams and quahogs. Tonight, we ended up hitting an area that contained a lot of rocks. All of them must be cleared from the dredge by the crew before the next tow can be performed. This sometimes can take as long as an hour, depending on what is collected. Scientists then sometimes question whether there could be surf clams and quahogs in this specific area, so they’ll prepare to do a set-up. A set-up involves towing the region five times with intervals of 200 yards separating each tow. This allows scientists to examine what exactly could be=2 0in a specific area, and if it was just chance that allowed so many rocks to be brought up in one specific tow. Also in the future, this clam survey will be done by commercial vessels; therefore a calibration needs to be done using the current dredge versus a commercial one. Set-ups help with this process.
Something else found in a recent tow: Scallops!
Personal Log
I am very happy that I had this experience as a Teacher At Sea. In the past two weeks, I have gained a wealth of knowledge regarding surf clams and quahogs, bur also what life at sea is like, and who the people are that conduct research to hopefully understand more about populations dynamics. I also have not been as tired before as I have been on this trip! Getting used to a time change by working through the night, and conducting so m any tows in a twelve hour period leaves your body fatigued. At 1:00pm when I’m finished with lunch, all I can think about is sleep.
When tows are brought to the surface, a neat variety of other things are often brought up as well. I have significantly contributed to my seashell collection by finding lots of different whelk, scallop, and snail shells, along with some sand dollars. I also kept a surf clam and a quahog shell as a reminder of my trip. Because each shell has its matching other half, they are each known as a clapper. I can’t wait to share all of my interesting stories, pictures, and experiences with my students back in Coventry, Rhode Island when I return. I could only hope that people who truly have an interest in science could experience something like this one day!
NOAA Teacher at Sea
Lisbeth Uribe
Onboard NOAA Ship Delaware II July 28 – August 8, 2008
Mission: Surfclam and quahog survey Geographical Area: Southern New England and Georges Bank Date: August 5, 2008
Chief Scientist Vic Nordahl, Chief Boatswain Jon Forgione and Chief Engineer Patrick Murphy discussing the best way to reattach the pump power cable to the dredge.
Ship Log
In the last 48 hours the engineers, crew and scientists have had to re-attach the power cable to the dredge (see photograph), fix the cracked face plate of the pump, replace the blade and blade assembly, change the pipe nozzles that direct the flow of water into the cage, and work on the dredge survey sensor package (SSP). Dredging is hard on the equipment, so some mechanical problems are to be expected. The main concern is for lost time and running out of critical spare parts. So far we have had great success with making the repairs quickly and safely.
Science and Technology Log
Collecting Tow Event and Sensor Information for the Clam Survey
Over the weekend I was moved up to the bridge during the towing of the dredge. I was responsible for logging the events of each tow and recording information about the ship and weather in a computerized system called SCS (Scientific Computer System). I listened carefully to the radio as the lab, bridge (captain) and crane operator worked together to maneuver the dredge off the deck and into the water, turn on the pumps, tow the dredge on the seafloor bottom, haul the dredge up, turn off the pump and bring the clam-filled dredge back on deck. It is important that each step of the tow is carefully timed and recorded in order to check that the tows are as identical as possible. The recording of the events is then matched to the sensor data that is collected during dredge deployment. As soon as the dredge is on deck I come downstairs to help clean out the cage and sort and shuck the clams.
Lisbeth is working on the bridge logging the events of each tow into the computer system.
My next job assignment was to initialize and attach to both the inside and outside of the dredge the two mini-logger sensors before each tow. Once the dredge was back on deck I removed both mini-loggers and downloaded the sensor data into the computers. Both sensors collect pressure and temperature readings every 10 seconds during each tow. Other sensors are held in the Survey Sensor Package (SSP), a unit that communicates with onboard computers wirelessly. Housed on the dredge, the SSP collects information about the dredge tilt, roll, both manifold and ambient pressure & temperature and power voltage every second. The manifold holds the six-inch pipe nozzles that direct the jets of water into the dredge. Ideally the same pump pressure is provided at all depths of dredge operation. In addition to the clam survey, NOAA scientists are collecting other specimens and data during this cruise.
Two small black tubes (~3 inches long), called miniloggers, are attached to the dredge. The miniloggers measure the manifold (inside) and ambient (outside) pressure and temperature during the tow.
NOAA Plankton Diversity Study
FDA and University of Maryland Student Intern Ben Broder-Oldasch is collecting plankton from daily tows. The plankton tows take place at noon, when single-celled plants called phytoplankton are higher in the water column. Plankton rise and fall according to the light. Plankton is collected in a long funnel-shaped net towed slowly by the ship for 5 minutes at a depth of 20 meters. Information is collected from a flow meter suspended within the center of the top of the net to get a sense of how much water flowed through the net during the tow. Plankton is caught in the net and then falls into the collecting jar at the bottom of the net. In the most recent tow, the bottle was filled with a large mass of clear jellied organisms called salps. Ben then filters the sample to sort the plankton by size. The samples will be brought back to the lab for study under the microscope to get a sense of plankton species diversity on the Georges Bank.
An easy way to collect plankton at home or school is to make a net out of one leg of a pair of nylons. Attach the larger end of the leg to a circular loop made from a metal clothes hanger. Cut a small hole at the toe of the nylon and attach a plastic jar to the nylon by wrapping a rubber band tightly around the nylon and neck of the jar. Drag the net through water and then view your sample under a microscope as soon as possible.
Biological Toxin Studies
NOAA Scientist Amy Nau hauls the plankton net out of the water using the A-frame. (Upper insert: flow meter; lower insert: plankton in the collection bottle after the tow).
Scientists from NOAA and the Food & Drug Administration (FDA) are working together to monitor clams for biological toxins. Clams and other bi-valves such as oysters and mussels, feed on phytoplankton. Some species of phytoplankton make biological toxins that, when ingested, are stored in the clam’s neck, gills, digestive systems, muscles and gonadal tissues. If non-aquatic animals consume the contaminated clams, the stored toxin can be very harmful, even fatal. The toxin affects the gastrointestinal and neurological systems. The rate at which the toxins leave the clams, also known as depuration rate, varies depending on the toxin type, level of contamination, time of year, species, and age of the bivalve. Unfortunately, freezing or cooking shellfish has no effect on the toxicity of the clam. The scientists on the Delaware II are collecting and testing specimens for the two biological toxins that cause Amnesia Shellfish Poisoning (ASP) and Paralytic Shellfish Poisoning (PSP).
NOAA Amnesia Shellfish Poisoning (ASP) Study
A group of naturally occurring diatoms, called Pseudo-nitzschia, manufacture a biological toxin called Domoic Acid (DA) that causes Amnesia Shellfish Poisoning (ASP) in humans. Diatoms, among the most common organisms found in the ocean, are single-celled plankton that usually float and drift near the ocean surface. NOAA scientist Amy Nau collects samples of ocean water from the surface each day at noon. By taking water samples and counting the numbers of plankton cells, in particular the Pseudo-nitzschia diatoms, scientists can better determine if a “bloom” (period of rapid growth of algae) is in progress. She filters the sample to separate the cells, places the filter paper in a test tube with water, adds a fixative to the tube and sets it aside for further study in her lab in Beaufort, NC.
Scientist Amy Nau filters seawater for ASP causing dinoflagellates.
FDA Paralytic Shellfish Poisoning (PSP) Study
Scientists aboard the Delaware II are also collecting meat samples from clams for an FDA study on the toxin that causes paralytic shellfish poisoning. When clams ingest the naturally occurring dinoflagellate called Alexandrium catenella, they accumulate the toxin in their internal organs. When ingested by humans, the toxin blocks sodium channels and causes paralysis. In the lab, testing for the toxin causing PSP is a lengthy process that involves injecting a mouse with extracts from shellfish tissue. If the mouse dies, scientists know the toxin is present. The FDA is testing the accuracy of a new quick test for the toxin called the Jellet Test Kit. After measuring and weighing a dozen clams from each station on the Georges Bank, Ben and Amy remove and freeze the meat (internal organs and flesh) from the clams to save for further testing by scientists back on land. At the same time, they also puree a portion of the sample and test it using the Jellet strips for a quicker positive or negative PSP result.
Personal Log
Pilot whales sighted off the bow!
The problems that we have experienced with regard to the dredge over the past few days are an important reminder of the need for the scientists and crew to not only be well prepared but also flexible when engaged in fieldwork. All manner of events, including poor weather and mechanical difficulties, can and do delay the gathering of data. The Chief Scientist, Vic Nordahl, is constantly checking for inconsistencies or unusual patterns, particularly from the dredge sensor readings, that might need to be addressed in order to ensure that the survey data is consistent and accurate. The time required to repair the dredge meant I was able to do a load of laundry. Dredging is very dirty work! Good thing I am using old shirts and shorts. I also caught up on a few emails using the onboard computers. Though the Internet service can be slow at times it is such a luxury to be able to stay in touch with friends and family on land. I still have two very special experiences that I wish to share before ending my log.
Late in the evening a couple of days ago, as we steamed toward our next tow station, I was invited to peer over the bow. The turbulence in the water was causing a dinoflagellate called Noctiluca to sparkle and glow with a greenish-blue light in the ocean spray. The ability of Noctiluca and a few other species of plankton and some deep-sea fish to emit light is called bioluminesense. A few days later we had the great fortune to see five pilot whales about 100 meters away, gliding together, their black dorsal fins slicing through the water, occasional plumes of air bursting upward through their blowholes (nostrils located on the tops of their heads).
Answers to the previous log’s questions:
1. What is the depth and name of the deepest part of the ocean? The Mariana Trench in the Pacific Ocean is 10,852 meters deep, (deeper than Mount Everest is tall – 8,850 meters). Speaking of tall mountains, the tallest mountain in the world is not Mount Everest, but the volcano Mauna Kea (Hawaii). It reaches 4,200 meters above sea level, but its base on the sea floor is 5,800 meters below sea level. Its total height (above base) is therefore 10, 000 meters!
2.What is the longest-lived animal on record? In 2007, an ocean quahog was dredged off the Icelandic coast. By drilling through and counting the growth rings on its shell, scientists determined it was between 405 and 410 years old. Unfortunately it did not survive the examination, so we do not know how much longer it would have lived if left undisturbed. This ancient clam was slightly less than 6 inches in width.
NOAA Teacher at Sea
Tiffany Risch
Onboard NOAA Ship Delaware II July 28 – August 8, 2008
Mission: Clam and Quahog Survey Geographical Area: South of Long Island, NY Date: August 2, 2008
Weather Data from the Bridge
Mostly cloudy with isolated showers
Surface winds: 5 to 10 knots
Waves: Swells 2-4 feet
Water temperature: 23o Celsius
Visibility: 7 nautical miles
The dredge being brought back up onto the ship after being deployed
Science and Technology Log
As I began my shift, I noticed on the map hanging in the dry lab that we are working our way towards an area southeast of Nantucket called Georges Bank. Georges Bank is a shallow rise underwater where a variety of sea life can be found. Before long, we were called to the deck for our first station of the morning. We set the dredge, hauled it back, sorted the catch, measured and recorded data, and moved on to the next station. Recording data and sorting are two of my favorite things to do, especially when it involves shucking the clams for the meat to be measured! My watch seemed to be on a record pace, as we managed to complete seven hauls all before breakfast at 5:00am. This process happens around the clock on the DELAWARE II, maximizing the amount of data we collect while at sea for two weeks.
Later in the day, the winch that is used to haul the dredge back from the water suffered a power problem. I and the person controlling the dredge noticed this right away, as one of my jobs is to switch the power on to the pump that the dredge uses. I alerted my watch chief, and also the chief scientist for this cruise who quickly began to assess the situation. Over the next hour or so, things became very busy on the back deck as the captain, engineers, and scientists tried to solve the problem. They did manage to get the power back to the winch again, which enabled the dredge to be brought back onboard the ship. The amount of talent exhibited by so many people on this ship continues to amaze me. They always have answers for everything, and Plan B for any situation is always on their minds!
Collecting and sorting the variety of marine life that we find. Here, TAS Risch holds up some sea stars.
Personal Log
Today was a really exciting day of sorting, as my watch found a variety of different organisms. I actually saw a live scallop clapping in the bucket after it was hauled up! Other interesting creatures included a Little Skate (Raja erinacea), which is a fish made of cartilage and is closely related to rays and sharks, a sea robin, sea squirts, hermit crabs, some sea stars, and even a few flounders. One of the more unusual characters that we encountered onboard was called a Yellow boring sponge, otherwise known as a Sulfur sponge or “Monkey Dung”. We take measurements of all of these things and quickly return them to their home in the ocean. Very early this morning, around 1:00am I visited the bridge, or the area where the captain controls and steers the ship from, to see what everything looks like at night. Crew member Claire Surrey was on the bridge tonight, making sure the ship stayed on its course. The area was very quiet and dimly lit by the various monitors that broadcast
information back to the officer in charge. The ocean was pitch black, and I could only see faint lights of a few other ships bobbing up and down in the waves very far away. What a cool experience to see the ocean at night, with a starry sky, and know that all types of instruments are guiding my voyage through the sea!
New Words/Terms Learned
Min-logs: sense temperature, depth, and pressure underwater on the dredge, and are brought back to the surface and recorded via computer.
NOAA Teacher at Sea
Lisbeth Uribe
Onboard NOAA Ship Delaware II July 28 – August 8, 2008
Mission: Surfclam and quahog survey Geographical Area: Southern New England and Georges Bank Date: July 31, 2008
“Bob” the Man Overboard Victim
Ship Log
Man Overboard Drill
Just as the day watch started our shift we heard three short blasts of the ship’s horn, signaling a “Man Overboard” drill. While the crew was on deck (both on the bow (front of the ship) and stern (back), the Chief Boatswains Jon Forgione and Leno Luis put on life vests and safety helmets and were lowered into the water in a rigid haul inflatable boat (RHIB). When those on board the ship sighted the dummy victim, we raised our arms and pointed in its direction. The rescuers then headed in the direction the crew were pointing. At the same time, the Operations Officer and Medical Person in Charge (MPIC) Claire Surrey readied her gear to perform life saving measures once the victim was safely brought on the deck. Rescue protocols are taken very seriously as they are designed to keep all members of the crew safe. Once the MPIC determined the dummy victim was breathing on their own and required no further medical assistance, the drill was over and the crew returned to their stations or berths (sleeping rooms).
Scuba Divers to the Rescue!
Not long after the man overboard drill, the dredge rolled when it was being hauled from the sea floor, wrapping the hawser (floating tow line) underneath the cage. To make matters worse, as the dredge was being lifted up the ramp on deck, the hawser became caught in the ship’s rudder. Our three NOAA Working Divers, Executive Officer (XO) Monty Spencer, Chief Steward (chef), MPIC Jonathan Rockwell and MPIC Claire Surrey suited up in scuba suits for a dive to untangle the rudder. NOAA Working Divers must complete a 3-week training course. They are skilled at ship husbandry, such as working on the rudder, propellers, zincs (metal zinc objects that are placed on the hull of a ship to attract corrosion), and the bow thruster (a tunnel through the ship with a propeller to help direct the bow when docking).
Chief Steward Jonathan Rockwell preparing to dive below the ship to untangle the hawser line from the rudder.
The diver breathes air through a mouthpiece, called a regulator, from a scuba tank of compressed air that is strapped to the diver’s back. The regulator, connected by a hose to the tank, adjusts the air in the tank to the correct pressure that a diver can safely breathe at any given depth. Originally called the “aqua-lung”, “scuba” stands for self-contained underwater breathing apparatus. Scuba gear has helped scientists explore the ocean, however, the equipment does have limitations. The deepest dive that can be made by a NOAA scuba diver is about 40 meters, but the average depth of the ocean is about 3,800 meters. The increased water pressure of the dive limits the depth of the descent of a scuba diver.
As Monty and Jonathan plunged into the ocean, the rigid haul inflatable boat (RHIB) was deployed with General Vessel Assistant (GVA) Adam Fishbein and Chief Boatswains, Jon Forgione at the tiller arm, to assist in diver rescue operations if needed. On standby in full scuba gear was MPIC Claire Surrey in case the divers ran into any trouble. In no time at all the divers freed the tangled hawser from the rudder and were back on board. At each step of the job, great care was taken to check all gear and ensure the safety of the crew.
Question: What is the depth and name of the deepest part of the ocean?
Mature Atlantic Surf Clam and Ocean Quahog
Science and Technology Log
As I mentioned in my first log, we are targeting two species of clams during our survey, the Atlantic Surf clams (Spissula solidissima) and Ocean Quahogs (Arctica islandica). They are very easy to tell apart, as the surf clam is much larger (about 18 cm in width) and lighter in color. “Quahog” (pronounced “koh-hawg”) originated from the Narrangansett tribe that lived in Rhode Island and portions of Connecticut and Massachusetts. Atlantic surf clams are a productive species, in that they are faster growing, with a lifespan of about 15 years, with variable recruitment (reproductive cycles). They are much smaller and typically found in more shallow waters (<50 meters) from Cape Hatteras to Newfoundland than the ocean quahog. The Quahog lives in depths of 50-100 meters in US waters (from Cape Hatteras up to the north Atlantic (Iceland), and also in the Mediterranean). Quahogs grow slowly, and typically live for more than 100 years, with infrequent and regional recruitment.
There is a great variety of material, both organic and inorganic that is collected by the dredge providing a snapshot of the habitat below. At times it is sandy, sometimes the sediment is the consistency of thick clay, in which case we must re-submerge the dredge for a few minutes to clean the cage. At other times large rocks and boulders are captured.
Live clams, shells and other material collected in the dredge. All the material is sorted, weighed and measured as part of the survey.
Atlantic Surf Clams and Ocean Quahogs live in a part of the ocean called the subtidal zone. Their habitat is the sandy, muddy area that is affected by underwater turbulence but beyond heavy wave impact. In addition to clams, our dredge is capturing a variety of organisms perfectly adapted to this environment, such as sponges, marine snails and sea stars that are able to cling to hard materials to protect them from being swept away by ocean currents and waves. Marine snails and hermit crabs are also able to cling to surfaces. Like the clam, many organisms have flattened bodies, thereby reducing their exposure to the pull of waves and currents. We find flat fish, such as flounder and skate, which avoid turbulence and their enemies by burying themselves in the sand. Flounder prey on sand dollars, another flat organism living in the subtidal zone. In many hauls of the dredge, the cage is filled with sand dollars. We have collected lots of other interesting animals, such as hermit crabs, worms, sea jellies, sea mice and, less often, crabs and sea urchins. The Sea Mouse is plump, about 10 cm in length, segmented and covered in a large number of grey brown bristles that give it a furry appearance.
Question: What is the longest-lived animal on record?
Personal Log
The main difficulty I have with writing this log is choosing what to cover. Each day is filled with new and interesting experiences. I am learning so much, not only about the science behind the clam survey, but also about the ship itself and the skills necessary to operate the ship and conduct a marine survey. Everyone has been extremely generous with sharing his or her knowledge and experience with me. While cleaning the inside of the dredge last night one of the wires made a small tear in the seat of my waterproof overalls. Now I know to pack a bike inner tube repair kit if I am lucky enough to be invited to join another survey cruise! One of those small rubber patches would have been the perfect for the job. I was able to find a sewing kit and in short order sewed the tear and sealed it with a layer of duct tape. Now I am ready to get back to work!
NOAA Teacher at Sea
Tiffany Risch
Onboard NOAA Ship Delaware II July 28 – August 8, 2008
Mission: Clam and Quahog Survey Geographical Area: South of Long Island, NY Date: July 30, 2008
Weather Data from the Bridge
Hazy in the morning with less than 6 miles visibility
Calm seas with little cloud cover
Wind speed = 5 knots
Waves = Wind drives waves < 1 foot
Water temperature: 23o Celsius
Tiffany uses a measuring board to obtain quahog lengths.
Science and Technology Log
Today started with an early morning shift, working from 12:00 am to 12:00 pm. As my watch took over, the DELAWARE II began steaming towards the first station of the day to conduct a survey of the surf clam and quahog size and abundance inhabiting this specific area. In order to complete a survey of the area, a dredge is used to capture any surf clams or quahogs that are pushed out of the bottom sediment. On the top of the dredge are hoses that push pressurized water onto the bottom to loosen up any bivalves. A bivalve is an organism that has shells consisting of two halves, such as in a clam or a scallop. The dredge is towed behind the DELAWARE II for five minutes at a speed of 1.5 nautical miles per hour. Attached to the dredge are sensors which transmit dredge performance information back to scientists in the dry lab to record and analyze. The accuracy of the survey depends greatly on the credibility of the sensor data, and therefore, scientists must monitor variability of the dredge. After the dredge is brought back to the surface, the load must be sorted, measured, and then discarded.
After listening to a presentation by Larry Jacobson, I learned a lot of new facts about both Atlantic sufclams (Spissula solidissima) and Ocean quahogs. Surf clams live only about 15 years, grow very fast, and can inhabit ocean waters stretching from Cape Hatteras in North Carolina to Newfoundland. These bivalves are found in waters less than 50 meters of water. Ocean quahogs on the other hand can live for greater than 100 years, are very slow growing, and are found in ocean waters between 50 and 100 meters deep from Cape Hatteras, around the North Atlantic to the Mediterranean.
Giving power to the hydraulic pump.
Scientists on this cruise are also interested in studying other aspects of the clam populations, such as a condition called Paralytic Shellfish Poisoning. Because bivalves are filter feeders, they eat by filtering food out of the waters around them. Sometimes, algae can contaminate clams using a toxin that is harmful to humans. When this happens and humans eat the shellfish, they themselves can become quite sick. Samples of clam meats are being taken during this research cruise to be studied back at a lab and determine what exactly is happening in regards to Paralytic Shellfish Poisoning.
Personal Log
Today has been quite interesting, as I moved through the many stations that are involved with conducting this survey. I was trained on how to measure clams in the wet lab, how to apply the power to the dredge in the dry lab, and even how to shuck a clam to retrieve the meat which is also measured. I was also quite amazed regarding how efficient everyone is on the ship, as we all have a job to do, and it all gets done before we arrive at the next station.
One of my highlights today was overcoming my sea sickness and finally getting my sea legs! Everyone is so supportive, from the officers, to the scientists, and to the volunteers who are all so nice and helpful. I’m looking forward to my next eight days at sea and learning more about the research being conducted.
