CORSACS: Controls on Ross Sea Algal Community Structure
2005:
A Research Cruise to the Ross Sea to Study What Controls the Phytoplankton DynamicsQuestions
from Mason Preparatory School, South Carolina, USA January 25, 2006
Hey Mrs. Sessions, Unfortunately, our cruise ends tomorrow so there is no
time for any more email correspondence. We are currently 7 miles outside
of McMurdo and our ship is stuck in some very thick ice. Last night we had all
4 engines running and we could only move 500 feet during 8 hours of backing and
ramming into the ice. The Russian icebreaker Krasin (that NSF had leased for the
season) has broken a propeller while trying to clear the channel of ice. NSF has
dispatched the Coast Guard icebreaker Polar Star and it is now en route from Seattle.
It will not be here for another 7-10 days. Meanwhile a dive team is trying to
repair the propeller of the Krasin at McMurdo. We are scheduled to fly out of
McMurdo tomorrow. Helicopters will arrive here today at 3 pm to start taking our
luggage and samples to the airfield. The helo's will come back tomorrow to pick
up the scientists getting off and take us to the airfield. All of this, of course,
is dependent on the weather. Yesterday afternoon a low pressure system developed
and we had "white-out" conditions. Temperatures were -25 degrees C with
winds blowing at 35-45 knots. It was also snowing very hard. Obviously, there
are no flights possible under those conditions. Next November we will probably
encounter those types of conditions regularly. OK, I have to go package
all our samples up for shipping as the helo is coming to get them... All
the best,
jack January 10, 2006 Hi Mrs. Sessions, Nice
to hear from you all. I'll try and get some new pictures up tomorrow....cheers,
jack
Have you been able to take a lot of samples? - John
Yes
John, we are taking thousands of samples every day. We do about 4 CTD's ever day.
There are 24 bottles on the CTD that collect water at different depths. Every
group takes samples for different measurements. For instance, the group from Stanford
takes samples to measure oxygen and carbon dioxide levels in the seawater. Our
group measures algal pigments and the gas DMS. The Delaware group is taking samples
for phosphorus and for DNA measurements. The group from VIMS measures nutrients
in the water and the photosynthetic rate. Then there is the group from Woods Hole
studying the concentrations of trace metals such as cobalt, zinc and cadmium.
The group from Bermuda is studying iron concentrations. I'll try to send along
a picture of these chemists measuring iron.
Is the water temperature
warmer than the air temperature? - Elliot
It depends on the day Elliot.
Some days are very cold especially when we are in the ice or near the Ross Ice
shelf. Today it's pretty close with an air temperature of -1.7 degrees Celsius
and a water temperature of + 0.5 degrees C. But we are now headed toward McMurdo
Sound where there is a lot of ice. We are going into the ice there to get supplies
that a helicopter will deliver to us. I will put pictures up to show the helo
operations tomorrow.
Does the algae stick to the ship (grow on the
ship while you are there)? Alex
Not really Alex. Usually the ship is
moving so fast that there is very little time for anything to attach to the ship.
Stuff that sticks to a ship is called bio-fouling. Paint on the hull of a ship
has an anti-bio-fouling agent that is specially designed to prevent exactly that
from happening.
Do humans affect the growth of phytoplankton and
algae? - MaryClaire
Good question Mary Claire! That's one of main questions
we're out here to try and figure out. Remember that it is humans who have put
large amounts of carbon dioxide in the atmosphere by burning gasoline, coal and
oil. We know that most of the carbon dioxide that man puts in the atmosphere goes
into the ocean. So the question is how will phytoplankton respond to increasing
amounts of carbon dioxide in the ocean in the future. We know that it will make
the oceans more acidic. We are performing tests to see how phytoplankton composition
and photosynthetic rates change with respect to different carbon dioxide levels.
Hopefully, we will have some results soon on that question. Does the
depth of the water affect the growth rate of the algae? - Elise Yes
Elise, it does. When particles (like phytoplankton) fall from near the surface
to the deep ocean they are broken down and turned back into nutrients by bacteria.
It's the same thing that happens when leaves from a tree hit the soil. Bacteria
will break down the leaf litter to release carbon dioxide into the air and nutrients
back into the soil. In the deep ocean these nutrients will remain for a long time
as currents will move them around it will be along time before they ever reach
the surface. If the particles fall into shallow areas then wind mixing the ocean
surfaces waters will bring those nutrients back to the surface where phytoplankton
can use them to grow.
January 9, 2006
Dear Mrs
Sessions, Hope you all had a good weekend. Glad to hear the students are
interested....Here are some answers to their questions. Have you seen
whales? If so, can you send any pictures? By Hunter Yes Hunter, we have
seen some whales but not as many as we usually see. I've attached a of the Antarctic
Minke whale that came to visit us. Minke whales are baleen whales. It actually
spyhopped next to the ship. Spyhopping is when they stick their head vertically
out of the water. Killer whales (also known as Orcas) usually also do lot of spyhopping
around the ice edge, maybe to see where there are penguins or seals that they
can eat. But most likely whales spyhop when they are in the ice because they are
afraid of becoming trapped in the ice. Remember they are mammals and need air
to breathe. So they spyhop to search for a way out of the ice. Because underwater
visibility is so poor during the late summer algal bloom, it may be easier to
see areas of open water from the surface than from below. Unfortunately, the Minke
surprised us all so nobody got a picture of it spyhopping.
How is
the growth of phytoplankton and algae in Antarctica compared with
the same
species here? By Julian
How fast does the algae grow and how thick
can it get?
By Kendall Good questions Julian and Kendall. Scientists
are still trying to understand that. The main difference, of course, between waters
off of South Carolina and those here is the temperature of the water. Temperature
has a big effect on phytoplankton growth rates. The water temperature here is
about 0 degrees C in the summer and -2 degrees C in the winter. Seawater freezes
at about -2 degrees C because the salt in the water lowers the freezing point
of water. Seawater near South Carolina is relatively warm. In August, the water
on Folly Beach reaches near 30 degrees C. Phytoplankton at warm temperatures can
divide and grow maybe 2 times a day in very warm temperatures. In cold temperatures
in Antarctica, phytoplankton will divide about only once every 2 days. That means
that if we have 2 cells that are healthy and dividing can you figure out the number
of cells that there would be in both places after 6 days? There are other differences
as well such as different species of phytoplankton present and the amount of nutrients
in the water. For instance there is not much iron dissolved in the seawater near
Antarctica so phytoplankton growth is limited by iron. In warmer waters, such
as off of South Carolina, nitrogen or phosphorus is more likely to be limiting
phytoplankton growth. Off course, during the winter in Antarctica there is no
sunlight so algae cannot grow. On the other hand, as you know there is plenty
of sunshine in South Carolina for algae to grow in the winter time. The
thickness of ice algae varies and depends on thickness of the ice, light and nutrients
in the water. If the ice is thick and there is alot of snow on top of the ice
then there is only a little light that will get through and so the ice algae thickness
at the bottom of the ice will be small. But if the snow cover is not too great
then the thickness of the ice algae can be thicker, maybe 6-12 inches thick. In
the water, algae usually can grow quite well as long as there is at least 1% of
sunlight that reaches them. In the Ross Sea that may only be at about 20 meters
depth. The waters around Antarctica are rich with nutrients, except iron.
Is
the volcano still active and does it affect the algae?
By Kelly
Yes
Kelly, Mt. Erebus is still an active volcano in Antarctica. It's about 12,444
feet high and last erupted in the early 1980's. When it is not cloudy near Ross
Island we can see the steam coming out of the top of Mt. Erebus. Recently, active
volcanos were discovered under the ice! The lava and steam can melt some of the
ice. That makes some of the remaining ice start to slide. This is called an ice
stream. If these volcanoes become much more active, giant pieces of ice could
slide off Antarctica. There is so much ice in Antarctica that if many large pieces
ever do slide off, the sea level of the ocean would rise and the world's climate
would change. We also know that large volcanic eruptions can affect algae
in another way as well. A big eruption like the one in the Philippines that happened
in 1991 on Mt Pinatubo sent so much dust and ash into the atmosphere that it blocked
some of the sunlight reaching the earth and oceans. So less sunlight reaching
the oceans meant that algal species that grow better at low light were at an advantage
compared to those that like to grow at higher light levels. This dust and ash
stayed in the atmosphere for almost two years and affected climate all around
the world. It may also have had an effect on phytoplankton species composition
in the ocean because some of the dust and ash may have alot of iron associated
with it. As I mentioned earlier iron can stimulate phytoplankton growth in seawater
around Antarctica. Questions from Mason Preparatory School January
5, 2006 Hi Mrs. Sessions and all the 5th graders at Mason Prep, Nice
to hear from you and greetings from the Ross Sea. Here are the answers to your
questions: Has the stormy weather passed? by Logan Logan, we've
have been very lucky with the weather so far. Luckily we haven't really had a
bad storm . The wind was blowing at about 25 knots the other day and that caused
some good sized waves. But our ship (we call it the Natty B) is great and does
not rock very much even with 6 to 8 foot waves. It is very stable because it is
so heavy for its size. It is 308 feet long and weighs 6200 tons. WOW, that's alot!
The weather today has calmed to just 5-10 knot winds and we're getting some snow
flurries.
Has anyone fallen in during the trip? by Nicholas
Nicholas,
nobody has fallen overboard. We attach lines to a belt that we wear if we are
working near the water. If anyone ever did fall into the ocean down here, they
most certainly would not live for more than 5 minutes in the water. The water
is so cold ( minus 2 degrees C) that you would pass out after just a couple of
minutes. I once sailed with a Captain from the Australian icebreaker "Aurora
australis" who said "In my 30 years of going to sea in Antarctica, three
men have fallen overboard, two of them were recovered dead, the other one was
not recovered at all". Is ice algae everywhere under the ice in
Antarctica? by Rachael Rachel, good question. After all ice is ice right?
Wrong! In Antarctica, ice comes in many forms. After all, Antarctica has 90% of
the world's ice, and that's 70% of the world's fresh water. Here's a quick description
of the different types of Antarctic ice: Ice Sheets: are formed by falling
snow, so they are made of fresh water. The ice sheets cover most of Antarctica's
land. Glaciers and Ice Streams: are actually frozen rivers of ice that come
from the ice sheets. They move slowly toward the sea. Ice Shelves: are made
of glacier ice that is attached to the land. But the shelves are actually floating
on the surface of the sea. Ice shelves can be hundreds of feet thick. We are very
close to the Ross Sea Ice Shelf down here. It is as big as the country of France. Icebergs:
are glacier ice that have broken loose from Antarctica. Bergs drift north to warmer
seas and melt. Sea Ice: is frozen seawater. It almost never gets thicker
than about 10 feet. There are many types of sea ice. "Fast ice" is sea
ice attached to the shore. "Pack ice" is sea ice that forms in the ocean
and has broken into pieces. Sometimes the pieces look like pancakes-this type
of ice is called "pancake ice". If we see any of that I will take a
picture for you. Sea ice algae need nutrients to grow just like land plants.
That's why we mostly find ice algae at the bottom of sea ice. There they can absorb
nutrients from the water. When our ship breaks through some sea ice the pieces
can flip over and we can see the ice algae on the bottom of the ice floes. Sometimes
there is so much ice algae on the bottom of the sea ice that it turns the ice
to a brown color. Ice algae is very patchy and sometimes we don't see any at all
under the ice. If the ice is very thick then there is very little sunlight that
can reach the ice algae and so they are unable to grow. If there is alot of snow
on top of the ice that also makes it hard for sunlight to get down to the bottom
of the ice. Scientists are still not sure just how much sea ice there is surrounding
Antarctica. We do know that every winter about 8 million square miles of sea ice
surrounds Antarctica, but during summer only about 1 million square miles of ice
is left after it melts. What was Christmas like on the ship? by Stephen Stephen,
our Christmas was very nice but also very different than the one you had. The
best thing about our Christmas was that we hit the pack ice on Christmas Day.
It was beautiful to see all the snow and ice. It also started snowing during the
day and we got to see some penguins and seals on the ice. We also had a "secret
santa" gift swap. That's when one person buys a secret present for one other
person on the ship. I received a nice book about the Norwegian explorer, Amundsen.
He led the first expedition to reach the South Pole in 1911. They left from the
Bay of Whales on the Ross Sea Ice Shelf. We are actually only about 120 miles
from that spot right now. We certainly do eat alot better now than those old Antarctic
explorers. Our Christmas lunch was delicious. We had turkey and ham with mashed
potatoes and all the other fixings. For Christmas dinner they barbecued some beef
tenderloin outside on the deck. We still worked on Christmas Day, though. Also,
have a look at the entries by Carol and Brian under the "Life at Sea"
section. Bye 4 now,
jd
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