Monthly Archives: May 2013

Photos from Andvord Bay

Here are some more photo updates from our crew in Antarctica!

Rich is helping prepare the mega core.  This device can recover small sections of bottom sediment and the water just above it.  It is important to sample both the bottom and the water to see what is happening at the boundary.

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Jeremy and Mackenzie are getting ready to deploy the camera system. They are both ship technicians that help us deploy and recover equipment.  Most importantly they make sure everything we do is safe.

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Another amazing sunset looking north from Andvord Bay.

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Julie is getting ready to bring the CTD on board the ship through the Baltic room door.  The Baltic room is heated to keep the water samples from freezing in the cold outside air.

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Julie is peeking out of the Baltic room waiting for the CTD to reach the surface.

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These are sample images from the FlowCam instrument.  This instrument takes pictures of tiny plankton that are in a concentrated water sample.  The water is pumped through the instrument in the lab on the ship.  The camera can see things ranging in size from 10 microns to 250 microns.  10 microns is about 0.00039 inches.

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The winds chased us out of Andvord Bay and brought in some impressive clouds.

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Categories: Life at Sea, Musings of an Oceanographer | Leave a comment

Single-Celled Predators!

When we think of predators, pumas, hawks, and killer whales may come to mind.  But, predators exist on the single-cell scale as well.  Here’s a picture of a single-celled predator called a tintinid, who’s trying to eat a large algal cell, the spikey diatom corethron.

tintinid

One mission on the cruise is to identify who’s eating whom in this Antarctic food web.  We’re looking directly at what the krill are eating, but we can also try to capture the feeding of even tinier predators.  Single-celled organisms that can be seen through a microscope are predators to one another, and to the algae in the water.  These tiny predators are known as zooplankton.  Using these bottles, incubated in seawater constantly flowing through large on-deck tanks, we measure the grazing of single-celled predators on the marine algae.  Basically, we’re testing whether or not the zooplankton are eating their veggies!

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We capture the signal of zooplankton grazing by incubating water over 24 hours, and measuring the growth of algae with and without grazers present.

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Grazing experiments are conducted in these large tanks, which maintain the temperature of the seawater (cold!  around -1.9 degrees Celsius!).  The sewater is constantly flowing through the tanks to maintain temperature, and prevent ice from forming.

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Magnificent Microbes

They’re small and mighty, the bottom of the food chain, and fuel for the ecosystem. Here are some pictures from under the microscope.  We’ve been cataloging the small stuff, because it’s important!  The algae (phytoplankton) that are featured in the pictures below use photosynthesis to fix carbon (food and energy!) using sunlight.  But the light is so low, with sunrise and sunset only about 5 hours apart.  This means that these single-celled energy powerhouses are true survivors, tolerant to low light levels and very cold temperatures.

Their morphology, or cell shape, reflects adaptations that allow them to find the sweet spot in the water column associated with the optimum level of sunlight.  The spikes and spines on some of these cells may also be used to avoid predation.

centric corethron radiolarian rhizo2 spiney2

 

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More pictures from Antarctica!

A recent trawl along the bottom brought back a few different animals that live on the seafloor.  This octopus is about 3 inches wide. It is hanging out on the side of a five gallon bucket.  We let it go after a few hours, and quite a few photos.

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All our meals are served in the mess.  The schedule is: breakfast 7:30-8:30, lunch 11:30-12:30, dinner 17:30-18:30 and mid-rats 23:30-:00:30.  Mid-rats is a second midnight dinner.  Some people get a bite to eat before going to bed, and others are just getting up to work all night long.  The ship runs 24 hours a day.  There are always people awake and working.

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We have been catching a lot of krill and somebody decided to make krill pancakes.  They taste like shrimp, and are an acquired taste.

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In the mess you pick up a plate and serve yourself in the food line.  So far we’ve had great salads and fruit.  There is always plenty to choose from.

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We had a sunny morning with lots of light streaming in the portholes.

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This is high noon.  For most of the day the sun is behind the mountains and hardly gets high enough to shine above them.  When the sun comes out the views can be pretty spectacular.

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It is very hard to judge the scale of Andvord Bay.  The edge of the water in this photo is about 2 miles away.  The mountain is 3500 feet tall.  The air is very dry and clear.  The mountains look a lot closer than they actually are.

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Live camera captures krill and seafloor

This is a photomosaic of the seafloor taken in about 500 meters of water. The complete image is made by combining many smaller overlapping photos. Underwater you can’t take a single large image. You can see the corners of the original images. Chris’s student Dave made this image. Dave is working on this type of image processing for his masters degree.

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This is a single image of the seafloor. We have been looking at the bottom to see if there are krill on the bottom.

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This is typical image showing a few krill swimming in front of the camera system.

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This is a krill swarm close to the bottom.

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This image shows a swarm of krill very close to the bottom. You can see the bottom in the background of the image and a lot of krill in a tight swarm on the right side. We are not sure what the krill are doing on the bottom.

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When no signal is a good signal

A sample of our krill catch.  Krill krill everywhere...but what are they eating?

A sample of our krill catch. Krill krill everywhere…but what are they eating?

A basic question of our project is how krill survive in low/no food conditions. What do krill do to survive the long, dark winter in the Antarctic? Do they reduce their activity and ‘hibernate’? Do they find a food source we do not know about? So, while winter in the Antarctic may not be a very attractive time to visit, we came here to observe krill in conditions of low food, and that just happens to be in late fall and winter. Measuring plant pigments in the water is one way to measure how much plant-like food may be available to krill. When we took samples at many depths today, we found there is almost no pigment anywhere. A little bit at the surface and less than little at the bottom. A normal concentration in our home estuary of Narragansett Bay may be around 3-4 and up to 25. The concentration we are measuring here is 0.1. So, while making such a small measurement is not satisfying to the mind who wants to detect and discover, the result is telling us that we have found exactly the conditions we are looking for. Now, we are off to see what the krill do under these ‘stressful’ conditions. Are they stressed, or more likely, do they have ways to cope?

-Susanne Menden-Deuer

Our filter manifold.  Water is poured into each cup, and filtered to capture the plant pigments in the water.

Our filter manifold. Water is poured into each cup, and filtered to capture the plant pigments in the water.

Categories: Musings of an Oceanographer, Science Updates! | Leave a comment

Scientist Profile: Kerry Whittaker

Kerry

Kerry Whittaker

Kerry is getting her PhD at URI in the laboratory of Dr. Tatiana Rynearson.  Kerry studies diatoms, single celled algae that are photosynthetic and are a great food source for krill.  Kerry uses genetic methods to follow populations of diatoms and these are similar methods that geneticists use to follow human populations and family relationships.  On this cruise, Kerry is collecting samples so that we can determine what kind of organisms the krill might be eating. To determine where to obtain her samples, Kerry profiles the water at every sampling station from surface to the bottom using an instrument package called a CTD-that’s short for temperature, conductivity (salinity) and depth.  There is also an instrument that measures autofluorescence from organisms containing chlorophyll and instrument that measures how light travels through the surface ocean.

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Kerry at the CTD data window following the downwater profiles of light, fluorescence, salinty, temperature and depth

These instruments are lowered into the water on the bottom of a large sampling frame that also hosts a rosette of bottles called Niskin bottles that are used to collect water at discreet depths.  The rosette and instruments are deployed via a very large winch and are cabled to monitors on the ship that show data in real time as it is lowered.  Scientists like Kerry watch the data as the instruments head down into the water toward the bottom and use this data to make decisions about where to capture water samples on the return trip on the way toward the surface.   For example, for diatoms which make carbon molecules from sunlight and oxygen, it is useful to know the depth of light penetration and depths where there may be a maximal signature of chlorophyll fluorescence.

Kerry collecting water

Kerry sampling water collected in the Niskin bottles

The water bottles on the rosette are held open with a spring loaded system that is also electronically wired to the cable on the winch that lowers it.  On the descent, the water flushes through the bottles and on the ascent once depths for water sampling are selected,  an electronic signal is sent to an individual bottle that releases the spring holding the bottle open. This snaps the bottle shut and traps water at a specific depth. Bottles are fired from the deepest depths to the shallowest depths.

Once aboard the ship, the water is collected via spigots at the ends of each bottle.  Each scientist is assigned specific bottles for sample collection.  Kerry filters water from each sampling depth onto filters that have specific pore sizes that select for different organisms.  Since diatoms are small the filters have pores that pass water through no bigger than thousandths of a millimeter.   Kerry uses a pressurized pump system to filter water and then she flash freezes the filters holding the diatoms (and other organisms that are trapped on the filters) in liquid nitrogen.  This cryogenically preserves her samples so she can extract DNA from the organisms trapped on the filters back in her laboratory at URI.

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Andvord Bay

Sunrise in Andvord Bay

Sunrise in Andvord Bay

The glaciers, the ice bergs, the icy mountains, whales and seals, they all came out for sunrise this morning in Andvord Bay.  At 9am the N.B. Palmer squeezed through a iceberg scattered channel into Andvord, just in time for sunrise.  This will be our second bay in which to conduct our krill studies.  On our first sunny morning of the cruise, we put down our pipettes and our nets to enjoy the transit into this impossibly beautiful location.  The reflections of cold mountains and blue glaciers reflected clear and deep into the ice-scattered water.  We were greeted by seals and whales almost everywhere we looked.  Here are some pictures that attempt to capture the beauty of this Antarctic morning.

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Leopard seal catching some rays

Leopard seal catching some rays

Oh, and because the sun sets at about 2:40PM, we also watched the moon rising over the bay.  Just as stunning.

Moonrise over Andvord

Moonrise over Andvord

Categories: Musings of an Oceanographer | 1 Comment

KISS

Rachel Greene:

The Kiss Method for sizing krill!

The Kiss Method for sizing krill!

I would like to briefly explain the research I’m conducting onboard the N.B. Palmer.  The main piece of equipment I am using is the MOCNESS, which stands for multiple opening and closing net system, which does exactly what it sounds like.   There are a series of nine large nets held around a ring, and a marine scientist controls the deployment from inside while collaborating with the marine techs on the back deck.  The marine scientist is able to see the instrument go down on the computer screens and can ‘fire’ a net at any time, which will close a sample of organisms at a specific desired depth.  So when the MOCNESS returns, each of the 9 available nets has a sample from the desired depths.  This instrument is used to collect organisms only (a similar machine called the rosette is used to collect water in the same fashion).  The nets are then emptied into numbered buckets and quickly brought to the lab where I will take a random sample of around 200 individual krill per net.  I then use the very simple but effective KIS, which is the krill imaging sizing system I made (although Meng takes credit for the acronym).  I then preserve the krill in formalin and lay them on a board, take a picture, and upload it to my computer.  I mastered this process down to four minutes!  I then take the image and upload it to a ruler board, where I can size the 200 individuals in about 5 minutes instead of perhaps the hours it would take to do it individually.  I do this for 200 krill per net.  Eventually I will compare this data to the ADCP, which is the Acoustic Doppler Current Profiler.  This instrument sends out sound, which hits a solid thing and bounces back.  Ergo it uses backscattering to see what’s in the water by the sound it sends back.  I this works, krill size, distribution, and biomass can be more properly determined just from the ADCP feedback.  So far, it seems that the larger krill are in the middle of the aggregation and the smaller guys are left out and remain on the outside of the swarm.  However, it will take more data and more MOCNESS tows to tell for sure!

Categories: Life at Sea | 1 Comment

Let the Sampling Begin!

Here in Wilhelmina Bay, it’s not all whale watching and penguin gazing. We’re out here to explore the science behind these amazing organisms–mostly, the small and abundant animals and marine algae supplying the food and energy for the “charismatic megafauna.”  We’ve been pulling out all of the stops, deploying all of our instruments into the water to sample the krill, phytoplankton, and even the sediment at the bottom of the ocean, in order to get a clear sense of the food web dynamics in this amazing ecosystem.

One of our krill experts on the ship, Meng, has estimated the abundance of krill in this single Antarctic bay to be 3.7 million tons!!!  3.7 MILLION TONS! This information is based on extensive surveys of the area that can detect the acoustic reflectance of krill swarms using ADCP, or Acoustic Doppler Current Profiler.

We know who’s eating the krill (our whale and penguin friends), but we want to know: what are all of these krill eating?!

Here’s a first glimpse at some of the ways that we’ve been sampling the environment in order to answer this question:

We use nets.  LOTS of nets!  By deploying these off of the ship, we can catch everything from krill to the phytoplankton that they feed on.  Here’s an example of one type of net that is used for sampling the Antarctic water column.

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We also use something called a MOCNESS–basically, a series of nets that allow us to sample krill at different depths.

We’ve also been sampling the sediment.  It has been suggested that, during times of the year when phytoplankton are less abundant, the krill may feed on sediment rich in nutrients. This sampling is fun…and VERY muddy!  Here’s a picture of our sediment “MEGA CORE”!

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This instrument is put over the side, and dropped to the bottom of the ocean (here, about 520 meters), where it sinks into the sediment to collect large columns of mud, bringing an intact sample to the surface.

We use a CTD (conductivity, temperature, depth) that can measure important properties of the water, and collect water samples at different depths, bringing the water to the surface for the scientists on board to analyze.

Once on board, we can use this water to conduct experiments that examine rates of algal growth, and the grazing of single-celled predators.  We use these on-deck incubators to conduct our experiments, while keeping the organisms cool.

on-deck incubator

We’ve also been conducting some REALLY COOL filming of the krill in the water!  We’ll update more on that later.  Also, stay tuned for an update on some krill experiments in progress–these involve tethering the krill (putting them on a leash!) and filming their response to different prey items.

This is a first glimpse at some of the cool sampling that we’ve been conducting.  Stay tuned for more pictures and updates as our findings emerge.

And, don’t worry Mom, we’re always wearing our hard hats on the back deck 🙂

always wear your hard hat!

Categories: Science Updates! | 1 Comment

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