Friday, August 31, 2012

Pteropod Videos

Here are a couple of pteropod videos that I put together.  The first is of Limacina helicina.  While watching, notice the shape of the spiral, the number of whorls, the presence of striations on the largest whorl and the beating heart.  On which side of the shell is the opening when the point is on top?  Most gastropods open on the right (dextral) but pteropods open on the left (sinistral).  These animals are about 1 - 2 mm in diameter. 

video

Limacina helicina 

At one station, many of the Limacina were laying eggs, shown in some of the photos below.

                
Limacina helicina. top one has egg strand still attached.
Egg chain of Limacina helicina

The second video is of Clio pyramidata.  These pteropods are quite a bit larger, up to a centimeter long.  Their bodies are not coiled like typical snails but stretched out and flared at the opening.  Look for the beating heart, the dark gut, and two yellow spots that I think look like eyes.
  video
Juvenile Clio pyramidata, enlarged ~ 50x

Larger Clio pyramidata, enlarged 12x
Nancy Copley

Thursday, August 30, 2012

Streaming the Wire

An essential part of the work at sea is deploying various pieces of equipment over the side of the ship to sample the ocean water column. On this cruise the gear going over the side of the ship are the Reeve Net for collecting live animals, the CTD Rosette for measuring physical, chemical, and biological parameters (temperature, salinity, oxygen, fluorescence, light transmittance), the HammarHead to measure broad-band acoustical backscattering, and the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) to capture zooplankton from 1000 m to the sea surface.

The trawl Winch Drum (right) and Traction Module (left) on the 0-1 deck of the New Horizon. This winch is used to tow the MOCNESS.
 
All over the side deployments with sampling to depth require a winch and wire on which the sampler is attached. The winches are sophisticated devices that hold thousands of meters of cable that can be paid out and hauled in at speeds typically ranging from a meter or two per minute up to 60 meters per minute. On the base of the drum there is usually a Lebus groove designed for the specific cable diameter to provide a perfect wrap of the first layer of wire on the drum.  Paying out the wire is usually not a problem, but hauling in requires a precision levelwind to lay the cable on the drum wrap after wrap and layer after layer with no gaps or cross-overs. A trawl winch with 0.68" conducting cable is being used to tow the MOCNESS off the stern of the New Horizon. In addition to a drum and levelwind, this winch also has a traction module to keep the wire spooling onto the winch at a constant tension.

The 0.68" cable being streamed over the stern of the New Horizon through the sheave on the A-frame.

At the beginning of this cruise, the first two MOCNESS tows to 1000 m encountered difficulties with the wire on the trawl winch not being properly laid down on the drum while hauling in. The ship's engineeers had to make manual adjustments to get the cable to lay properly, which involved intervals of stopping the winch and sometimes paying the wire back out before hauling in again. This resulted in a less than optimal MOCNESS tow where the object is to sample the water column uniformly as the system is hauled from its maximum depth to the surface while opening and closing nets. Making adjustments to fix the problem while the tow is in progress is difficult and it is even more difficult in port where operating the winch is not possible without extra shore side support. So on the way out to station with the ship steaming at 9 kts, we streamed the wire with just a weight on the end of the cable to allow the engineers the time to make adjustments to the winch tension device and levelwind. We paid out more than 1800 meters of wire and then the process of making adjustments to the traction module and the levelwind started as the wire was being hauled in. Time will tell if the problems were fixed and the towing of the MOCNESS will go smoothly for the rest of the cruise.

The Res Tech Meghan Donohue, Chief Engineer Tom Schuller, and oiler William Bouvier making adjustments to the trawl winch.
The Res Tech Meghan Donohue bringing in the cable termination and weight at the end of streaming the cable.
The winch display as seen inside the main lab. The graph at the bottom shows the tension (in lbs) experienced by the winch during the time over which the cable was being streamed.
Peter Wiebe (text and photos)


Wednesday, August 29, 2012

She Studies Seashells

G'day! or should I say Bonjour?!

My name's Liza Roger, and I'm a new addition this year to the Ocean Acidification Pteropod Study team. I am currently doing research for my PhD at the University of Western Australia in Perth, under the supervision of Dr Malcolm McCulloch and Dr Julie Trotter at the School of Earth and Environment. I performed part of my undergrad studies in France (I'm French) and finished in Australia. After I graduated, for my Master's degree I studied changes in modern pteropod shells (size, thickness and porosity) collected from regions off the northwest and northeast coasts of Australia over a 45-year-period.

Map of Australia showing my Master's sampling locations (Scott Reef, Rowley Shoals, Browse Island, North West Cape, Lizard Island, Whitsunday Islands, and Heron Island)

My research results suggested that pteropods off Northern Australia (tropical pteropods!) may have been influenced by changes in seawater chemistry over the past few decades, particularly a decrease in the availability of the carbonate ion that pteropods need to produce their aragonitic shells (i.e., a decline in the aragonite saturation state). While most pteropod studies concentrate on polar and sub-polar species I seem to be the 'odd-one' studying tropical pteropods. Pteropods are distributed circumglobally in all the world's oceans though and I strongly belive tropical pteropods should not be over-looked.

Soooo....
 
What am I doing in the Northeast Pacific then?

I met part of the OAPS team in 2011 at a zooplankton conference in Chile and our common interest in pteropods brought us together again when they invited me to join them on this research cruise. The team/lab (ARC Centre of Excellence for Coral Reef Studies) I am part of back in Australia focuses on calcification and concentrates on developing new analytical methods intended to improve the understanding of the impacts of global climate change on the marine environment. Most people in my lab work on corals and calcifying algae so, again, I am the 'odd-one' working on planktonic molluscs!

High magnification images of pteropod shells made with a Scanning Electron Microscope. Top image is of a fracture along the surface of the shell of a specimen of Creseis acicula showing how the shell is made of two crossed lamellae (i.e., layers). Bottom image is of the dorsal surface of the shell of a Diacavolinia longirostris showing the ribbed growth-line patterns.

So, here I am, on the R/V New Horizon, collecting pteropods to study their calcification. Up until now, scientists have studied the dissolution of pteropod shells under different environmental conditions but the actual production of the shells (i.e., calcification) seems to have been a little neglected; I hope to shed some light on the topic...

Here are a few of the questions I am trying to answer:
  • What is the chemical composition of pteropod calcium carbonate shells?
  • Do pteropods regulate the pH of the fluid  they use to calcify their shells (internal or extra-cellular fluid)?
  • If so, do they up-regulate pH? Down-regulate? Or something else?
  • In terms of shell calcification, are there differences between species? Ocean basins? Polar vs tropical?
A Limacina helicina shell, dried and ready for analysis back home. Photo L. Roger.

So far we have already caught abundant Limacina helicina in our Reeve net and I have preserved a number of them to analyze once I'm back home in Australia. On that note, I hope to get back to you later in the cruise with some answers and in the mean time we steam towards new horizons...

Liza Roger

Tuesday, August 28, 2012

Newport, Oregon: Rocky Intertidal

Hi, Amy and Leo here,

Since we had some due dates and timelines to meet, we had to work the few days we had on land and stay in the vicinity of Newport, but we still had some time to visit the beautiful and rich intertidal of the Oregon coast.

The Oregon coast is part of the California-Oregon Upwelling System, driven by the California Current, which makes it one of the most productive areas in the world. This high productivity supports a large and diverse amount of fauna.  Currents bring deep water up to the surface with a lot of nutrients and this lets phytoplankton (the food of the sea) grow. With a lot of food around you get a lot of animal life too! The downside of upwelling, particularly in the northern part of this system, is that sometimes the deep water is low in oxygen and high in carbon dioxide. This region is thus another system that seems to be particularly vulnerable to climate change, but that question is for another day and another expedition. For the meanwhile we were just enjoying the beauty of the system.
Yaquina Head cliffs and rocky shore.
The high cliffs, on top of the rocky intertidal zones, are the habitat of the California Ground Squirrel

California Ground Squirrel warming up on the asphalt on the path to Quarry Cove, Yaquina Head. Photo: A. Maas

From the top of the cliffs it is easy to spot Harbor Seals resting on the rocks, and large colonies of cormorants.

Photos: A. Maas

Diversity in rocky intertidal zones is particularly high due to the small patches of different habitats we can find just within a few feet from the water’s edge. From regions exposed to the waves fronts, dominated by gooseneck barnacles, several species of acorn barnacles, and California mussels, you move on to the more protected internal pools full of calcareous tubeworms, anemones, limpets, chitons, seastars, sea-urchins and many others.

Exposed to the wave action, the frontal areas are dominated by strongly adhered sessile fauna, like barnacles, mussels and gooseneck barnacles. Photo: A. Maas

Depending on the amount of time that a particular pool is exposed to the air between tides, there is variability in the range of temperature and salinity levels (saltiness) that the animals experience. This creates a range in the distribution of both fauna and algae depending on their tolerance to drastic changes in their environmental conditions. This ranges from big changes in the higher pools, that suffer more contrasting levels of temperature and salinity, to the lower ones, were the conditions are more constant and are only exposed to slight changes during strong tidal events.

Intertidal rocky shore under Cape Perpetua. Upper pools are more protected from the mechanical stress of the waves, but they are exposed longer to the air temperature and evaporation, making them a highly variable environment. Lower pools are subject to less stress due to more constant temperature and salinity conditions. Photo: A. Maas

 Scorpion fish in a tidal pool in Quarry Cove, Yaquina Head. Photo: A. Maas
Purple sea urchins in a protected pool in the surroundings of Cape Perpetua. Photo: A. Maas
Green sea anemones near Cape Perpetua. These anemones have unicellular green algae living on their tissues in a symbiotic relationship. Photo: A. Maas
Chiton on Yaquina Head. These mollusks have eight plates protecting their back. Photo: A. Maas
This rich area also has large colonies of sea lions. More comfortable with close interaction with humans than seals, sea lions have no problems occupying human-made structures like harbor jetties and piers or, like in this case, resting under a human-crowded tourist pier on the Newport Waterfront. Photo: A. Maas
All of this diverse natural life supports a strong fishing community which, as a result, ended in some wonderful meals for us. In combination, the lovely views and good food make it a fantastic place to spend a few days. (Note: there are also some really nice espresso drive-throughs).
Amy and Leo at Cape Perpetua enjoying the windy clifside. Photo: L. Blanco-Bercial

Monday, August 27, 2012

What We Did On Our Summer Vacation

by Nancy Copley

As a result of the generator breakdown on the R/V New Horizon, the science party unexpectedly found itself with 5 days on land before setting off again for another 23 days at sea.  This was the perfect opportunity to re-energize and explore the area.  Oregon is a beautiful state with many natural and cultural attractions.

Here’s how we spent our time:

Portland, OR, stock photo
VooDoo Doughnuts  Photo: S. Chu
After dropping off several people at the airport, a group – Sophie, Kelly, Nick - explored Portland and found its highlights to be the breweries, music stores, VooDoo donuts, and Powell’s Bookstore.


From there, they proceeded to Crater Lake for a quick swim in its bracing waters. Photo: A. Bergan




Another group – Nancy, Katherine, Britta - headed for REI in Eugene where they rented camping gear and proceeded to Crater Lake for several days of hiking and roughing it.  Upon their return, the cabin bunks looked fairly luxurious!


 
Others – Aleck, Amy, Leo - explored closer to Newport where the intertidal zone is especially diverse. More on this in a blog post coming soon. Photos: A. Wang


Staying in a nearby hotel felt pretty pleasant and the fast internet made getting work done a breeze. Photo: L. Blanco-Bercial


Drift Creek Falls  Photo:P.Wiebe
Suspension bridge over Drift Creek Falls.  Photo: A. Bergan
We returned from our various escapes with a day and a half to spare so many of the group went on a hike over a suspension bridge to Drift Creek Falls. 
… followed by a visit to a local winery.  Photo: N. Copley

Now we're ready to head back to sea.  Check back soon to see what we find in our night time surface plankton tows.