Newsgroups: lter.ced Path: LTERnet!news From: bph@virginia.edu Subject: CED 2.10 Message-ID: <1993Dec3.235518.10378@lternet.washington.edu> Sender: news@lternet.washington.edu Organization: Long Term Ecological Research Date: Fri, 3 Dec 1993 19:05:38 GMT ***************************************************************** ***************************************************************** *** *** *** *********** *********** ********** *** *** * * * * *** *** * * * * *** *** * * * * *** *** * ********* * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** * * * * *** *** *********** *********** ********** *** *** *** ***************************************************************** ***************************************************************** Vol.2 No.10 :::::: file name:CED2.10 :::::: December 1, 1993 ***************************************************************** ***************************************************************** CED METADATA ---- CED is the Climate/Ecosystem Dynamics bulletin board ofthe LTER network. In CED, you will find exchanges of ideas, information, data, bibliographies, literature discussions, and a place to find experts withinthe LTER community. We are interested in both climate controls on ecosystems and ecosystem controls on climate. As this is an inter-disciplinaryactivity, we hope to provide things that you might not come across in your work atyour LTER site. CED is a product of the LTER climate committee and contributions to CED for general e-mail release may be sent to either David Greenland of Andrews LTER [Greenlan@oregon.uoregon.edu] or to Bruce Hayden of the Virginia Coast Reserve LTER [bph@envsci.evsc.virginia.edu]. We expect that the scope of CED will evolve and reflect the interests of the contributors and users of this service. CED will be issued as the preparation work gets done (usually monthly). Back-issus of CED may be requested from Daniel Pommert [daniel@lternet.washington.edu] by the file name given in the masthead. Daniel can also add people to the CED mailing list. Feedback on CED from LTER scientists is welcome (non-$$$$ contributions also welcome.) For example, please forward citations of climate & ecosystem publications on your site. We are keeping a LTER wide bibliography on Climate/Ecosystem Dynamics that we pass on via E-mail. ***************************************************************** ***************************************************************** *** *** *** *** *** PLEASANTLY DEMENTED *** *** *** *** *** ***************************************************************** ***************************************************************** CED gets its share of e-mail mail. Many provide ideas for CED. My thanks for them all. Some send appreciations and complements. Most of these I enjoy and file them away for as bad-day tonic. Every once in a while, one comes along that has seven complements in a row. These beauties need to be shared CED readers because because they speak volumes about the joy of research both funded and never-could-be-funded. Here it is. "I got a kick out of your fathead/pinhead data set; clearly you are either: (1) tenured, (2) not funded by NSF, (3) immune from prosecution, (4) too old to give a damn, (5) under-employed with too much time on your hands, (6) pleasantly demented, or (7) some multifactorial combination of the preceding ; I suspect the latter.... Whatever the explanation, I'm delighted with the result. I chuckled the whole day -- and I needed that!" Cheers, --Jeff Kennedy Jeff also sent along some great stuff on "ice flowers" from ESA's Ecolog-L. The January issue will cover than and make some additions to ice flower formation problem. ***************************************************************** ***************************************************************** *** *** *** *** *** OXYGEN CLIMATE AND ROAST DINOSAUR *** *** *** *** *** ***************************************************************** ***************************************************************** The extinction of the dinosaur extinction problem is a problem. It just won't go extinct. Just a few weeks ago the asteroid that foul-tipped off Yucatan was up graded in size and fire-power when the crater was found to be bigger than first thought. The bigger the asteroic the deader the dinosaurs. Now, at the Geological Society of America meeting in Boston (10/26/93), comes word from USGS's Gary Landis (That's Landis not Larson. Larson is another dinosaur extinction speculator.) that the dinosaurs were respiratory-system challenged and that when the oxygen in the atmosphere fell from 35% to 28% they had no Jurassic Park sanatorium as a retreat.I think oxygen in the movie was only an air passage sufficating 20%. The 28% was curtains for them. Landis contends that 2/3 of the dinosaurs were gone before the foul-tip off Yucatan. The fall in oxygen from 35 to 28% took some 300,000 to 500,000 years and was complete by 65 million years ago. Richard Hengst, Purdue physiologist, says "There were some serious problems with trying to get air into [a brontosaurus]." His choice of words suggest a mouth-to-mouth respiration. I think Richard means that the small, horse-sized nostrils of the brontosaurus and others just were not up to the job. What a big sucking-sound there must have been. At 35% oxygen, I am not so sure that any but the most agile dinosaurs would last long at all. Lovelock in Gaia states that the probability of a lightning flash started fire increase 70% for each 1% rise in oxygen concentration above 21%. Above 25% most terrestrial areas would be like LA with brush fires with Santa Anna winds. Lovelock's numbers are based on lab work by a colleague, Andrew Watson of Reading University. LTER forest-pyro types might brief CED readers regarding oxygen climate and fires. Anyway it would look like the dinos would have to hang around 50% fuel moisture habitats or become roast dinosaur. Like the DNA in Jurassic Park, Landis' oxygen data comes from gas trapped amber, Minnesota amber. Landis notes that for the dinosaurs the drop from 35% to 28% is like going from sea level to 7,000 feet. I am from a sea level LTER and the oxygen quality of the air Estes Park provides me with great sympathy for the brontosaurus with horse-sized nostrils. I was thinking back to the residents of Estes Park, the ones that I remember, the cafeteria staff. Did they have unusually flared nostrils. Even if they had had obviously large nostrils I would probably have attributed it to the aromas from the roasting dinosaurs. I think that is what Tom Callahan said we were eating; something about Aunt Erma's Saturday night special. As you know I was rather busy with the cranium and had not paid much attention to nostrils. Looking back on it, it would have been possible to use the conical ear plugs that John Vandicastle provided as a measuring device. I could have put a scale on them with a ball point pen and surveyed nostril diameters. It is my good fortune that we will not hold the next All Scientist Meeting at Estes Park. ***************************************************************** ***************************************************************** *** *** *** *** *** AMBER WAVES OF GRAIN *** *** *** *** *** ***************************************************************** ***************************************************************** Wheat, oats, barley, rye, rice and prairies on breezy days have a striking resemblance to ocean waves. In very light winds we see, what the sailors call cat's paws on the water surface. Even these slight winds can propel a small sail boat. You can see the cat's paws working their way across the water surface. Sitting on your green and yellow automatic combine you can see cat's paws turn and twist the grain heads and the field begins to undulate. In strong winds, the sea turns into a maelstrom and the wheat field rolls and boils and large areas of blow-downs often result. At these speeds even the forest canopy looks like the sea with it superimposed waves. So, where is all this leading? Climate Dynamics (1933) 8:277-285 has a nice little article with answers to the question: What if we increased the waves at sea, would it affect the climate of the air? CED readers can quickly scan back through back issues on surface roughness and we see that CED has been pre-timely in addressing this feedback between the surface and the atmosphere. Anyway, the article is by Ulbrich, Bu[umlout], Schriever, von Storch, Weber and Gchmitz (yep, German colleagues) is titled "The effect of a regional increase in ocean surface roughness on the tropospheric circulation: a GCM experiment." Well, now you know what they did. They made a regional patch of ocean rougher by commanding that the waves on the surface of the sea be bigger than they are on the average;and, then run a big GCM with this roughed-up surface and see what happens. Everything is the same expect one variable is changed and that is why they call it an experiment. They did their wind commandment to the Southern and Indian Oceans south of 40S. The models were run as permanent July. That means there was no annual cycle. It is always July in the model. They increased the surface roughness (Zo) of the ocean by about 3 mm. They made the waves bigger than this but the calculated Zo change was +3 mm. You get about this much change on land if you switch from steppe to prairie. So you can think of this GCM experiment in these fanciful terms: The Southern Oceans are not covered with water but are all wonderful CPR quality steppes and then you change them to tall grass prairie and ask would that change our climate? Well, here is what they found. The rougher surface "significantly modifies the tropospheric circulation in the Southern Hemisphere." Tropospheric (surface to higher than the jets fly) winds decline by 10% or 2 m/s or 4.5 mph. That is not peanuts when you consider that average wind speed around the good old USofA run from 9 to 13 mph! But that is not the end of it. "The poleward eddy momentum flux is reduced in the upper troposphere and the meridional eddy sensible heat flux is reduced in the lower troposphere. Zonal and mean and eddy kinetic energy are consistently reduced." TRANSLATION PLEASE! The eddies they are talking about are whirls and swirls the size of synoptic weather system [storms]. It is a less stormy Southern Hemisphere, less heat and momentum are transported from low latitudes of surplus to the high latitudes where thee quantities are in short supply. And. The winds aloft don't blow as fast. CED readers should remember that I have written on the subject of a global equilibrium between how big and rough the vegetation is and how strong the winds are. In this article, they made-up a rougher sea and the hemispheric winds slowed down. Now slower winds make less-big waves at sea. Now, you must remember that this is a computer experiment. I know of no way that the waves a sea can get bigger except by making the winds stronger! Stronger winds make bigger a sea which now make slower winds. This is a negative feedback. On the other hand man is rather good at transforming the terrestrial landscape roughness on the order of changing from steppe to prairie or forest to field, or steppe to desert. Changes in these surfaces should change climate. Make the surface rougher and the winds slow down. Make the surface smoother and the winds speed up. Now, when winds get stronger plants, especially woody plants, get rougher (sturdier) and offer more drag to the wind. So, in addition to land use change changes in surface roughness, we also have a vegetation feedback to worry about. Rough vegetation gets rougher when the wind speed picks up. Rougher surface makes slower winds so the vegetation does not have to get so rough. ***************************************************************** ***************************************************************** *** *** *** *** *** LEAFING OUT, LEAF FALL, ROUGHNESS *** *** & CONTROLS ON CLIMATE *** *** *** ***************************************************************** ***************************************************************** My library delivered a nice companion article to my amber waves of grain item. It was in the journal Boundary Layer Meteorology. On the off chance that you don't read each issue, I will relate the part that most interests me. The article basically says that when the leaves are off the tree, the tree is a rather rough sort and when the leaves are on, the canopy gets smoother and less rough. So, in the leafed-out season the roughness of the canopy changes about he same amount as in the ocean waves experiment above. All else being equal, they never are, the winds should be faster in summer than in winter for the same pressure gradient because you loose less mechanical energy to the canopy. Unfortunately the pressure gradients are usually stronger in winter than in summer. Now there are some real howlers in summer, thunderstorms, tornados and hurricanes. ***************************************************************** ***************************************************************** *** *** *** *** *** DON'T ASK, DON'T TELL *** *** *** *** *** ***************************************************************** ***************************************************************** I am easily impressed with the modern lexicon of Gerganesk-wordsmithy for capturing ideas in a minimalistic fashion. In search of modernity, my CED "Don't Ask, Don't Tell Award" for 1993 goes to John Hobbie and the Arctic Lakes LTER for their succinct hypothesis statement: "Top Down, Bottom Up." So, where is this little offering going? A student came to my office on November 14 and asked "How do trees loose their leaves?" I went into a soliloquy on the abcsission layer. Like a leaf, I was cut off short. "No. No. I mean in what order do trees loose their leaves," he asked. I naturally thought of white oak first and said, "Top Down, Outside In." Even with the thrill of Hobbiesk hypothesis coining, I was sure I was right about white oaks. I asked the student what was his observation. He said he had seen the white oak and was impressed. However, the tulip poplar was Bottom Up for sure. He wanted to know why some trees were Top Down and others Bottom Up. The Top Down screamed "logarithmic wind profile" to me. It is windy up there in the tree tops. Winds have their leaf-ripping ways first at the top of the tree. A physiologist might say "more sunlight higher up, more starch storage and delayed abcsission layer formation. The Bottom Up to me seem to whispers nocturnal inversion, low minimum temperatures at the surface, early leaf death. Well, I told the student I would look around at some trees and see what I could discover. Most of our fine Virginia trees were near the terminus of their leaf fall but not all were. The sugar maples were Top Down, Sun Side Last, i.e. Wind Blasted and Sun Challenged. On a quick drive to Richmond, and about 50 mileseast of Charlottesville, sweet gum trees start to show up. I saw sweet gums of all sizes and they were clearly Bottom Up. Both the sweet gum and the sugar maple were Yellow Leaves First, Red Leaves Last. Something physiological here! Are sugar bound red pigments involved? Physiologists write that starches in the petiole delay leaf fall. Close inspection proved that the Bottom Up tulip tree and the Bottom Up sweet gum were greenest at the top and the top-down sugar maples, beech and willow oaks were greenest at the bottom. Keep Green, Last Longer. As best I can tell, free standing sycamore youth of some 25 feet or so are Bottom Up and the adults All At Once. I think green ash is All At Once and Fast while dogwoods are All At Once but Slow. Red, black and scarlet Oaks so far look Top Down but the process will not be complete for months as they hold some leaves until spring. More on that a bit later on. The dieceous Ginko provided an additional twist. The female ginko pregnant with putrid, gray drupe-like fruit had not a leaf anywhere. The proud, non-odoriferous, male trees had just turned bright yellow leaves. Leaf-fall was just beginning. Ladies before Gentlemen or a titanic-life-boat Women and Children First. The best female ginko at UVa are at the library bus stop. Lingering at this bus stop in mid- to late-November is minimal. You even see the occasional backpack with the typical caustic white stain. I used to think it was the birds but the stench is unmistakable. ***************************************************************** ***************************************************************** *** *** *** *** *** LEAF ABSCISSION AND THE DEATH OF SIEGFRIED *** *** *** *** *** ***************************************************************** ***************************************************************** Siegfried of Nibelungen-lied fame became "almost" invulnerable to his enemies because he bathed in the blood of the dragon Fafnir. The "almost" was unfortunate for Siegfried. When he took his Fafnir blood bath and abscised linden leaf fell on his back and prevented Fafnir's blood from touching that spot. Siegfried's leaf spot is akin to Achilles heel! Anyway Siegfried's enemy, Hagen, located the spot and dispatched Siegfried. The other old timer who needs mention when it comes to the whys of leaf fall is Theophrastus (285 BC). He, in addition to collecting weather lore, noted that trees keep their leaves longer if moisture is available and shed earlier if the soil is dry. He also noted that a younger tree keeps its leaves longer than an old one. Some plants develop and keep a fine living abscission layer for each leaf when the leaf opens in spring. Other species build the abscission layer when the day length dwindles in the fall. It is the destruction of the abscission layer that sets the stage for leaf fall. When the balance between the abscission hormone ABA exceeds retardation hormones like IAA, GA and GK, the cells of the abscission "turn to a jelly like" consistency as the pectins get converted to pectic acid and then to the water soluble form. This happens when starch levels in the petiole are low. And if this process is fast, then soon each leaf is only held to the plant by the vascular tissue (xylem and phloem) in the petiole. Snap that life-line and the leaves flutter to the ground. Wind is a good snapper! Now the winds do do something else. Experiments with shaking, in the privacy of a greenhouse, was shown to have the following sequential effect: shake the tree, leave calm for some minutes, and like magic leaf fall begins. It is suggested that the mechanical damage of shaking initiates a chemical process that further weaken the abscission layer and fall begins. Some plants start the development of an abscission layer. The chlorophyll dies off, other pigments display themselves, the leaf reaches full death, except for cells in the abscission layer. Winter begins and the leaves do not fall. Spring comes. Physiological processes return and the continued development of the abscission layer progresses until the leaf is only attached by the xylem elements and then leaf fall can take place. The leaves that do fall in the fall and winter, usually due to strong winds, fall because the petiole broke at some other place than the abscission layer. These retarded leaf-droppers are termed "marcescent." Drop the term marcescent at your next cocktail party and see the heads turn. Marcescent species here in the good US-of-A include Quercus coccinea, Q. velutina, Q. marilandica, Q. rubra, Fagus grandifolia, Ostrya virginiana, and Acer Saccharum. Each of these differ a lot in how easy it is for the winds to break their petioles during winter. American marcescent oaks are more marcescent as youth than as an adults. When you hew a tree in summer the leaves die before the abscission layer is finished and the leaves stay on the downed tree for a rather long time. I call this necrotic marscescence at cocktail parties. Low light levels brings on abscission and if light is high enough to promote starch accumulation, abscission is put off for a while. Photoperiod is often involved. Acer saccharum kept in 16 hours of light keep their leaves up to 5 months longer. In potted plants, high soil nitrogen led to high petiole auxin and low rates of leaf fall. ***************************************************************** ***************************************************************** *** *** *** *** *** BUTONIC AND HEXANOIC FATTY ACIDS *** *** A FEW MORE WORDS ON THE GINKO *** *** *** ***************************************************************** ***************************************************************** The fame of the Ginko is 1) it is so old a species it has "outlived" the pests that once pestered, and 2) the stench of its pre-germinated offsprings. Fruit of this broad-leafed, diecious gymnosperm contains a fertilized egg that does not do its mitotic thing until the process of germination begins. The "outlived" pests folklore was transmitted to me in my first botany class (1960). I always thought this lore came from the near perfect leaves that persist up to the aspen-yellow day of abscission and leaf fall. As noted above, the drupe-like children fall after the leaves fall from the female tree. These fruits are little butanoic and hexanoic fatty acid bomblets. They plop on the ground and wait for well shod readers and diners to grind them into the pavement to release aromas for all to enjoy. If you don't have ginkos near by get some old romano cheese and let it get real rancid, capture the butanoic and hexanoic fatty acids, concentrate about 300 times and take a sniff. That is what a ripe, ginko fruit is like. The buff-colored pit in the fruit is prized in Asian cooking. Okoshi, a Washington DC harvester uses rubber gloves on his hands and trash bags over his shoes and scoops up 3 or 4 pounds per year. Preparation: slice one end of the "nut"; remove husk and you have something that looks like a lima bean (baby lima size); boil 5 minutes with touch of baking soda; remove the skin of what you got; and, saute quickly in a little salted oil and use in chawanmushi. This good-chow idea comes from the Washington Post. Enjoy! DC has ginkos of all sexes and mid-November they gets as much attention and discussion as the weather. Now just why the male ginko keeps its leaves green until the fruit start to fall from the female edition and turn yellow during the height of the bombardment is beyond my ken. Someone in the LTER network must know such things! Please speak up. ***************************************************************** ***************************************************************** *** *** *** *** *** THE ELECTORATE HAVE RULED *** *** *** *** *** ***************************************************************** ***************************************************************** On global warming, Energy Secretary Hazel O'Leary on the MacNeil-Lehrer Report said, "The Administration came to grips with this issue when we were standing for election ... and to reargue or relitigate the science, I think, is a waste of our time." It is so nice to know that we can resolve scientific differences during our quadrennial contest for the Oval Office. I have been in the climate change business from Lyndon's first and only term. I see a trend. Johnson asked the Army War College to poll scientists on a new ice age a-coming. Ice age was the worry of the 1970s. "Consensus" Lyndon's way. Gallup-with-margin-of-error polling of scientists at national meetings began in the 1980s. Now, we have this little moo-er from Ms. O'Leary to mark the way of the 1990s. I look forward to the future when negative campaigning pits scientist against scientist. Beware, you may be some Pol's Willie Horton in 96 election or at the start of the next millennium. It is not clear to me that we as scientists, let alone ecosystem scientists, are up to the rough stuff of politics. ----------------------------------------------------- | Bruce P. Hayden | | VRIGINIA COAST RESERVE LTER | | 101 Clark Hall | | Department of Environmental Sciences | | University of Virginia | | Charlottesville, VA 22903 | | (804) 924-0545 | | bph@viginiia.edu | | bph@lternet.edu | | CED| ------------------------------------------------------ .....................................................