WINTER IN ANTARCTICA...
NIGHT LASTS 6 MONTHS OF WINDY, FREEZING DARKNESS...
THEN COMES ANTARCTIC SPRING AND SUMMER-6 MONTHS OF DAY... AND NEW LIFE.
THE PACK ICE BEGINS TO BREAK UP...
LIGHT COMES BACK TO THE SOUTHERN OCEAN.
MICROSCOPIC PLANT LIFE BLOOMS.
BILLIONS OF TINY CREATURES FEED ON THE PLANTS.
PENGUINS FEAST ON THE NEW ABUNDANCE... BRINGING IT HOME TO HUNGRY CHICKS.
IN TURN, SKUAS SWOOP DOWN ON ADELIE CHICKS, AND LEOPARD SEALS FEAST ON UNLUCKY PENGUINS.
HUMPBACKS GORGE ON TINY PLANKTON... AND KILLER WHALES STALK PENGUINS.
titles: The Antarctic Food Web
IN THIS VIDEO, WE'LL EXPLORE THE ANTARCTIC FOOD WEB, FROM SMALL TO LARGE, IN THE AIR AND IN THE OCEAN.
titles: Studying the Marine Ecosystem:
AND WE'LL SEE HOW RESEARCHERS USE COMPUTERS AND CALIPERS, TO STUDY PLANKTON, PENGUINS, AND PETRELS… ALL AMAZING EXAMPLES OF THE ANNUAL CYCLE OF LIFE IN THE MOST EXTREME ENVIRONMENT ON EARTH.
***
titles: program 3
Life in Extreme Environments
The Antarctic Food Web
title: The Antarctic Food Web
THE ANTARCTIC FOOD WEB-ONE OF THE MOST INTRIGUING EXAMPLES OF THE TRANSFER OF ENERGY AND THE RECYCLING OF MATTER THROUGH AN ECOSYSTEM...
PARTICIPANTS IN THE UNITED STATES ANTARCTIC PROGRAM REFER TO THE CONTINENT AS... "THE ICE." RIGHTLY SO--ABOUT 90% OF ALL EARTH'S ICE IS FOUND IN ANTARCTICA.
EACH ANTARCTIC WINTER FROZEN OCEAN WATERS DOUBLE THE SURFACE AREA OF THE CONTINENT.
THIS ANNUAL EXPANSION AND CONTRACTION OF THE ICE CHANGES THE ENVIRONMENT OF ALL THE CREATURES WHO LIVE ...ON ...IN ...OVER AND UNDER IT.
IN THE HEART OF THE CONTINENT, AROUND THE POLE, "THE ICE" IS RELATIVELY LIFE-LESS--WITH JUST MICROBES AND HARDY HUMANS ABLE TO SURVIVE.
BUT AROUND THE CONTINENT, OVER AND UNDER THE ICE AND OCEAN SURFACE, THIS CHILLY DESERT BLOOMS.
super graphics on screen:
Land temperatures
-70 degrees
Ocean temperatures
1-2 degrees
ON LAND TEMPERATURES CAN DIP TO MINUS 70 DEGREES CELSIUS, WITH FIERCE WINDS OF OVER 100 MILES AN HOUR...
BUT UNDER THE OCEAN, IT'S A CONSTANT ONE TO TWO DEGREES.
LIFE HERE HAS ADAPTED TO THE CHILL, AND THESE POLAR WATERS ARE EVEN MORE PRODUCTIVE THAN THOSE OF THE TROPICS!
ALL YOU NEED TO SET THE ENGINE OF THIS RICH MARINE ECOSYSTEM RUNNING IS SUNLIGHT TO DRIVE PHOTOSYNTHESIS, THE CHEMICAL PROCESS THAT PROVIDES ENERGY FOR PLANTS AND, IN TURN, THE CREATURES WHO LIVE ON PLANTS.
BUT IN ANTARCTICA, UNLIKE THE TROPICS, SUNLIGHT IS NOT AN EVERYDAY PHENOMENON.
MONTHS OF COMPLETE DARKNESS FOLLOW MONTHS OF DAY, AND SO ALL LIFE HERE HAS ADAPTED BODY SYSTEMS AND BEHAVIOR TO THIS ANNUAL "PULSE" OF ALL IMPORTANT ENERGY.
WITH THE RETURN OF SUNLIGHT, THE SEA-ICE BEGINS TO BREAK UP.
titles for each of these creatures/steps in the chain?
"Ice algae"
ALGAE LIVING IN THE ICE ITSELF FALL DOWN INTO THE WATER, A GIFT FROM ABOVE FOR HUNGRY CRITTERS COMING BACK TO ACTIVE LIFE.
title: "phytoplankton"
DOWN IN THE WATER, MICROSCOPIC PLANTS, CALLED "PHYTOPLANKTON", BLOOM.
title: "krill"
IN THE ANTARCTIC SUMMER A HOST OF CREATURES GRAZE ON THESE PLANTS.
MOST IMPORTANT FOR LIFE IN ANTARCTICA IS KRILL, A TYPE OF SHRIMP, GROWING TO 1 TO 2 INCHES IN LENGTH.
ON THE SURFACE, GIANT HUMPBACK WHALES OPEN THEIR GAPING MOUTHS AND FILTER VAST AMOUNTS OF WATER TO COLLECT THE KRILL.
title: "Adelie penguins"
ADELIE PENGUINS, WHO HAVE LIVED ALL WINTER OUT ON THE PACK ICE, NOW BUILD NESTS OF ROCK ON THE ISLANDS AROUND THE ANTARCTIC PENINSULA.
PENGUIN PARENTS TAKE TURNS INCUBATING THEIR EGGS, AND THEN CARING FOR THE NEWBORN CHICKS.
KRILL IS THEIR FAVORITE FOOD, AND ADELIE COLONIES ARE STAINED RED WITH SMELLY LEFT-OVERS.
title: "Brown skua"
ADELIE CHICKS, IN TURN, ARE PREY FOR AGGRESSIVE BROWN SKUAS, WHO OFTEN MAKE THEIR NESTS CLOSE TO PENGUIN COLONIES, SWOOPING DOWN TO GRAB EGGS OR SMALL CHICKS.
title: "Leopard seal"
OUT IN THE OCEANS PENGUINS FORAGING FOR KRILL ARE THEMSELVES PREY FOR LEOPARD SEALS.
THESE SLEEK AND POWERFUL PREDATORS ALSO EAT KRILL, BUT PENGUINS ARE AN IMPORTANT PART OF THEIR DIET.
title: "Fur seal"
KRILL IS ALSO ON THE MENU FOR ANTARCTIC FUR SEALS, WITH THEIR DISTINCTIVE FLIPPERS, FINE WHISKERS AND RICH COATS.
ELEPHANT SEALS, NAMED FOR THEIR DISTINCTIVE, TRUNK-LIKE PROBOSCES, ARE THE LARGEST SPECIES OF SEAL TO BE FOUND ON THE ICE.
MALES CAN GROW TO MORE THAN 20 FEET IN LENGTH.
ALONG WITH SQUID AND FISH THEY TOO EAT--GUESS WHAT???--KRILL!
ONCE HUMANS INVADED THIS ECOSYSTEM, HUNTING WHALES, FUR SEALS AND ELEPHANT SEALS CLOSE TO EXTINCTION.
TODAY RESEARCHERS NOT HUNTERS CREW THE BOATS... AND SCIENTISTS RECOGNIZE THAT THIS RICH WEB OF RELATIONSHIPS, FROM PLANKTON TO KRILL TO PENGUINS, SEALS AND WHALES IS PERHAPS THE LARGEST MARINE ECOSYSTEM IN THE WORLD.
THAT'S WHY, EACH SEASON, MEMBERS OF THE UNITED STATES ANTARCTIC PROGRAM HEAD SOUTH TO INVESTIGATE SEASONAL AND YEARLY VARIATIONS IN THE AMOUNT OF ICE, AND KRILL.
THEIR MISSION? TO STUDY HOW LIFE IN THE MOST EXTREME CONDITIONS ON EARTH RESPONDS TO CHANGES IN THE ENVIRONMENT.
title: Studying the Marine Ecosystem
title: LTER
ROBIN ROSS IS CHIEF SCIENTIST FOR THE MARINE COMPONENT OF "LTER"--A LONG-TERM ECOLOGICAL RESEARCH PROJECT, DESIGNED TO STUDY THE INTERACTION OF ORGANISMS AND THE ENVIRONMENT ON AND AROUND THE ANTARCTIC PENINSULA.
THIS IS HOW SHE AND HER COLLEAGUES STUDY THE ANTARCTIC FOOD WEB... AND THE TECHNIQUES THEY USE.
Robin Ross:
So we have a series of stations that we visit repeatedly, every single year, throughout this area that's about 400 kilometers by 200 kilometers, so a pretty big area. We come to a station and we do the same things at every station. There are three of these things...
TITLE TO ID BOPS
One of them is with an instrument called BOPS, which stands for Bio-Optical Profiling System, and that's a big mouthful, but basically this is the workhorse of our program, and BOPS is critical not only for understanding the characteristics of the water column, but it also is the instrument that brings the water up that everybody uses in order to understand the plants, the microbes that are growing within the water column.
titles:
"BOPS" MEASURES OCEAN TEMPERATURE AT DIFFERENT DEPTHS...
SALINITY, OR SALT CONTENT OF THE WATER...
HOW LIGHT OR DARK IT IS AT DIFFERENT DEPTHS...
AND SOMETHING CALLED "FLUORESCENCE"...
Robin Ross:
What the fluorescence measures is actually one of the pigments that is in the plants, it kind-of tells us how much plant material is in the water column.
When the BOPS comes back on deck, there are a series of water bottles on them, and those water bottles have closed at different depths, so the BOPS is bringing water up from 500 meters, from 400 meters, and then from the whole series of depths, close to the surface, in the lighted area, where all of the production is going on.
And different people come out and they take samples from the BOPS and they go back and they measure the gases-whether there's a lot of oxygen in that water.
...and they're also going to be measuring nutrients, so they'll tell you whether there's a lot of phosphate, or nitrate, in the water.
AT THE BOTTOM OF THE ANTARCTIC FOOD CHAIN ARE THE MICRO-SCOPIC, FREE-FLOATING PLANTS KNOWN AS "PHYTOPLANKTON."
Robin Ross:
The phytoplankton are really the grasses in the oceans, they do wax and wane just as grasses grow well in the summertime, and they don't grow so well in the wintertime. And some of the same factors that control the growth of the grasses on your lawn actually control the growth of the phytoplankton in the ocean, and in the Southern Ocean, one of the major factors in going to be light, because in the southern ocean there's darkness for about six months of the year.
ANOTHER PART OF THE LTER STUDY IS TO ANALYZE MINERALS AND ORGANIC MATERIALS DEPOSITED INTO THE OCEAN.
FOR THAT RESEARCHER DAVE KARL, FROM THE UNIVERSITY OF HAWAII, USES "SEDIMENT TRAPS."
BUT IN >THESE< WATERS, THAT'S EASIER SAID THAN DONE!
WORKING WITH SLIPPERY ROPES AND CHAINS WHEN THE OCEAN'S KICKING UP AND YOUR RESEARCH VESSEL IS PITCHING WILDLY REMINDS YOU THAT YOU'RE DOING SCIENCE IN THE MOST EXTREME ENVIRONMENT ON EARTH.
ONCE YOU KNOW WHAT THE PLANTS ARE ABSORBING FROM THE OCEAN, YOU'RE READY TO MOVE UP THE FOOD CHAIN AND SURVEY SOME OF THE SMALL BUT ALL-IMPORTANT CREATURES WHO EAT THE OCEAN "GRASSES"... KRILL.
RR:
...there are numerous animals in the southern ocean, including Antarctic krill, that are grazers, so you might think of them as the cows of the ocean, they're eating the plants, so they're eating the grasses of the ocean, and these animals tune their reproductive cycles and their life cycles so they can take advantage of these pulses of primary production.
So what you see is a pulse of both primary production, and of reproduction of the animals, that occurs in that spring and summer period.
KRILL ARE PRETTY SMALL, BUT SOME RESEARCHERS THINK THERE MAY BE MORE KRILL THAN ANY OTHER CREATURE ON EARTH!
AND THEY HAVE AN IMPORTANCE TO THE ANTARCTIC MARINE ECOSYSTEM BEYOND THEIR SIMPLE NUMBERS.
RR:
...The Antarctic krill really are the food, the major food, the dominant prey item, for a vast majority of the seabirds and of the seals and of the whales.
So if you think of this in building terms, a "keystone" is the part of an arch, that if you take that keystone out, the arch collapses. So you need to think of krill as being the keystone, that if you remove krill from the ecosystem, then the food, the major food for many animals, would disappear and the life cycles of those animals would also probably crash.
IN ADDITION TO "BOPS", ROSS'S TEAM USES AN INSTRUMENT THEY CALL-FOR OBVIOUS REASONS-A "BIO-FISH."
STABILIZED BY TAIL FINS, THIS METAL FISH SENDS OUT PINGS OF SOUND PULSES THROUGH THE WATER. WHEN THEY BOUNCE BACK FROM SOMETHING SOLID, ROBIN KNOWS THERE'S "KRILL DOWN BELOW!"
BUT ROBIN AND COLLEAGUES NEED TO KNOW MORE DETAIL ABOUT THE KRILL THAN THEY CAN DISCOVER JUST BY ECHOES.
FOR THAT THEY USE A GOOD, OLD-FASHIONED NET.
Robin Ross:
We want to know a lot more about the physiology of krill, we want to know how well they're doing, Is this a good year for them? Are they able to produce a lot of eggs? Are they able to grow a lot that year? Are they fat, or are they skinny? What's happening with them? Is this a good year for this population, or is this a bad year for this population?
WHEN KRILL DO WELL, THE RESEARCHERS THINK, ALL OTHER CREATURES IN THE ANTARCTIC FOOD WEB ALSO THRIVE.
IN YEARS WHEN KRILL ARE ABUNDANT, ADELIE PARENTS CAN FIND ADEQUATE SUPPLIES CLOSE TO THEIR NESTS, AND SO CAN RETURN QUICKLY TO RELIEVE THEIR MATES, AND PROTECT THEIR HUNGRY CHICKS AGAINST MARAUDING SKUAS.
RESEARCHERS BILL FRASER AND DONNA PATTERSON, WHO HEAD UP THE SEA-BIRD PORTION OF THE LTER, ARE MEASURING HOW FAR ADELIES HAVE TO TRAVEL IN SEARCH OF FOOD, BY PLACING RADIO TRANSMITTERS ON THEM.
Bill Fraser:
...we measure the amount of time that the birds spend at sea. Foraging trip durations are supposed to be a very sensitive indicator of the amount of food that is available in the foraging environment of Adelie penguins, and specifically we're interested in krill, that's obviously the item that's at the base of the food web in the Antarctic ...and our long-term data do in fact indicate that foraging trip durations increase or decrease in a very sensitive way depending on how many, on the abundance of krill within, say, 50 kilometers of Palmer Station.
AT THE VERY END OF THE FOOD CHAIN, GIANT PETRELS MAKE THEIR LIVING OFF THE LEFT-OVERS OF OTHER CREATURES.
THEY FLY VAST DISTANCES IN SEARCH OF FOOD, AND RETURNING TO NURTURE THEIR SINGLE LARGE CHICK FOR CLOSE TO A YEAR, UNTIL IT'S READY TO LEAVE THE NEST.
Donna Patterson:
These guys will go out and scavenge, so they can scavenge locally, they can scavenge at quite a distance. Australia, South Africa, New Zealand, and they go, they cover that ground between May and July.
The female for this nest, which I haven't seen for a few days, she could be off the coast of Chile right now. Or she could be eating a dead whale by Rothera, we just have no way of knowing that. So they'll forage wherever the food supply is.
My goal is to get satellite transmitters on them so that we know exactly where they're going, what they're doing, how long they're going for, and how their range changes throughout the breeding season. And what kind of impacts are these chicks feeling, these pairs that are breeding around Palmer, where are they getting their food. At this point it's still quite a mystery where they go.
FOR ALL THESE CREATURES, THE INTER-ANNUAL VARIABILITY OF THE ICE IS KEY TO WHO WILL THRIVE AND WHO WILL DIE EACH SEASON.
Bill Fraser:
If you could imagine the Southern Oceans as an engine, we're looking at sea ice as a fuel that runs that engine. The advance and retreat of the sea ice has been linked to increases or decreases of krill abundance, increases and decreases in phytoplankton. And so you would naturally expect that birds, which are dependent on these food resources, would also respond to sea ice, by showing increases or decrease depending upon what's going on with sea ice dynamics in any particular year.
TO SUPPLY >OUR< GROWING POPULATION, WE HUMANS HAVE INCREASINGLY BEGUN TO HARVEST KRILL-FOOD FOR SO MANY CREATURES IN THE ANTARCTIC FOOD WEB.
HUNTING ALMOST MADE MANY SPECIES OF WHALES AND SEALS EXTINCT...
BUT PERHAPS STUDIES LIKE THOSE OF ROBIN ROSS AND HER COLLEAGUES CAN HELP US AVOID ONCE AGAIN ENDANGERING THIS AWESOME AND INTRICATELY-CONNECTED MARINE ECOSYSTEM...
