The Ice Ages Matter (Even Today)

A very large percentage of the earth’s land masses were covered by glacial ice during the last glaciation. Right now it is about 10%, but during the Ice Age it was much more. Enough of the earth’s water was trapped in this glacial ice that the oceans were about 120 to 150 meters lower than they are now. The thicker ice sheets were one or two kilometers thick, and they tended to slide around quite a bit, grinding down the surface of the earth and turning bedrock into dust and cobbles.

ResearchBlogging.orgThen the ice went away, but the effects of the ice having been there are still being felt. A paper coming out next week in Nature explores the effects of deglaciation on the oceans. We can see the effects of the ice in the flooding going on right now in the Red River Valley on the North Dakota-Minnesota border. The lack of native worms in the northern regions of North America, and the survival of a number of rare plants is related to the deglaciation process. The effects of the great ice sheet and it’s subsequent melting have shaped the landscapes and cityscapes of many regions.

South Minneapolis is the largest part of the city in terms of both land area and population size. Minneapolis is called the City of Lakes (and thus, our basketball team is “The Lakers” ( … or did they move somewhere else, can’t remember … ), because of the lakes in west side of the city. If you look at a map of Minneapolis and surrounding areas, you’ll see that you can connect these lakes together between two roughly parallel lines, and that these lines indicate the outer limits of an ancient river channel. The river channel is still very much in place, and if you get down on the ground you can see where the sides of this channel are even where there are no lakes. The lakes are simply spots within the channel that were filled with more ice than sediment as the glaciers melted away. When the ice melted, a depression was left behind, and that depression is now a lake.

This explains why most of the lakes around here, most of which were formed from ice melted in the glacial ’till’ (as the stuff is called) are round. Imagine a concentration of big chunks of ice of any shape in one area below the ground. Maybe they are 30 feet to 200 feet below the present surface. It takes them forever to melt, but eventually they do and even if the void left behind is filled with water, the sediment collapses into the void. Now, think of this void as the lower part of an hour glass. as the sediment from above sifts and pours down into the void, the space that is above the passage way into the void is more or less unformly empties of its sediment, which means that an odd shaped void down deep is displaced and becomes a globular (round, from the top) shaped void above. A rounded circular depression in the landscape, which in turn becomes a lake.

If you take a broader view of the region, you can see that there are segments of ancient river channels all over the place, and if you start connecting them together, you will see that there is no way that these channels can be matched up to be the single channel of some ancient river. Rather there is a web-like network of channels everywhere. At any given time in prehistory, one or two rivers meandered across this region using some subset of channels.

If you remove all the glacial sediment and leave only the channels, what you would actually get is a landscape consisting of buttes and mesas separated by u-shaped valleys. It would look roughly like the badlands of the Dakotas.

One of these ancient channels (as discussed here) is the large recent course of the Warren River, and it is the nature of this valley’s formation that contributes to the modern day flooding we see in the Red River Valley, which occupies part of this ancient water route.

Getting back to the peer reviewed paper at hand.

This is the abstract from the paper, and I’d like this abstract to serve two purposes:

Rivers are the dominant source of many elements and isotopes to the ocean. But this input from the continents is not balanced by the loss of the elements and isotopes through hydrothermal and sedimentary exchange with the oceanic crust, or by temporal changes in the marine inventory for elements that are demonstrably not in steady state. To resolve the problem of the observed imbalance in marine geochemical budgets, attention has been focused on uncertainties in the hydrothermal and sedimentary fluxes. In recent Earth history, temporally dynamic chemical weathering fluxes from the continents are an inevitable consequence of periodic glaciations. Chemical weathering rates on modern Earth are likely to remain far from equilibrium owing to the physical production of finely ground material at glacial terminations that acts as a fertile substrate for chemical weathering. Here we explore the implications of temporal changes in the riverine chemical weathering flux for oceanic geochemical budgets. We contend that the riverine flux obtained from observations of modern rivers is broadly accurate, but not representative of timescales appropriate for elements with oceanic residence longer than Quaternary glacial-interglacial cycles. We suggest that the pulse of rapid chemical weathering initiated at the last deglaciation has not yet decayed away and that weathering rates remain about two to three times the average for an entire late Quaternary glacial cycle. Taking into account the effect of the suggested non-steady-state process on the silicate weathering flux helps to reconcile the modelled marine strontium isotope budget with available data. Overall, we conclude that consideration of the temporal variability in riverine fluxes largely ameliorates long-standing problems with chemical and isotopic mass balances in the ocean.

If you read that, your head probably hurts because it is a typical scientific abstract written to not be understood by the average person. First, I want to tell you briefly what it means, then I want to pick out a few sentences and hold them up as reasons that that authors who wrote this and the editors who let it pass should be flogged. (Flogging is British, right? This is Nature. So, right, flogged.)

What it means is this: The elements that are dissolved in the ocean change over time more than we would expect if this was simply a matter of the hard parts of the continents slowly eroding into the ocean, and the ocean getting rid of some of these elements when they settle to the bottom of the ocean or go somewhere else. It turns out that after a glacial period is over and the ice goes away, there is extra chemical stuff eroding into the ocean because the glaciers ground up more of the rock than would normally be eroded to contribute chemicals to the ocean. Interesting. Simple. Important. Not hard to understand.

But this is hard to understand:

In recent Earth history, temporally dynamic chemical weathering fluxes from the continents are an inevitable consequence of periodic glaciations.

Let’s break it down.

“In recent Earth History..”

This is a paper about the earth. And history. That this is Earth history and recent tells us nothing but adds mystery. This is nota mystery paper. Give dates. Such as, “During the last two to five million years” ..

“temporally dynamic chemical weathering fluxes”

OMG give me a break. Temporally = over time. Dynamic = changing, variable. Fluxes = changes. The word “chemical” in a paper about “elements and isotopes” means nothing. Oh, and by the way, isotopes are elements… no need to use the extra words.

Try: “Over time, changes in weathering”

“are an inevitable consequence of periodic glaciations.”

That’s OK, but it is really just hoiti toiti language. So, this:

In recent Earth history, temporally dynamic chemical weathering fluxes from the continents are an inevitable consequence of periodic glaciations.

… would be readable and more literate if it was dynamically fluxuated into this:

During the last 2-5 million years, changes in weathering from the continents happened because of periodic glaciations.

Is that so hard?

Here’s a half dozen more bits of the abstract.

… To resolve the problem of the observed imbalance in marine geochemical budgets, attention has been focused on uncertainties in the hydrothermal and sedimentary fluxes.

… the physical production of finely ground material at glacial terminations that acts as a fertile substrate for chemical weathering.

… we explore the implications of temporal changes in the riverine chemical weathering flux for oceanic geochemical budgets.

We contend that the riverine flux obtained from observations of modern rivers is broadly accurate, but not representative of timescales appropriate for elements with oceanic residence longer than Quaternary glacial-interglacial cycles.

… Taking into account the effect of the suggested non-steady-state process on the silicate weathering flux

…we conclude that consideration of the temporal variability in riverine fluxes largely ameliorates long-standing problems with chemical and isotopic mass balances in the ocean.

How would you rewrite these?

Vance, D., Teagle, D., & Foster, G. (2009). Variable Quaternary chemical weathering fluxes and imbalances in marine geochemical budgets Nature, 458 (7237), 493-496 DOI: 10.1038/nature07828

Comments

  1. #1 Stephanie Z
    April 4, 2009

    As an editor? With a match.

    Then I’d tell them to explain it to their teenage child, get the kid to go into another room to write it down and send that to me, in txt if necessary. That would be less painful to rewrite.

  2. #2 Mike Haubrich, FCD
    April 4, 2009

    I found a cool picture of what the glacial plain looks like on the Red River Valley when photographed through the air. Streaks remain even after all the soil was turned over from prairie to tilled soil. It’s embedded in this page.

  3. #3 Darren
    April 4, 2009

    Because the range of 2-5 million years is accurate right?

    I’m detecting a theme here. You get worked up over things that most people could care less about. Most normal people discount poorly researched articles and fill in the gaps themselves and don’t get in a tizzy over it.

  4. #4 Greg Laden
    April 4, 2009

    Darren: Thanks for visiting. Are you questioning 2-5 million years? Let’s hear your alternative ideas. Have you read the paper? Are you suggesting a longer time range or a shorter time range?

    Also, read the original post more carefully. I know reading is hard, but you can do it. Nowhere do I suggest that the research is poor.

  5. #5 Wayne Conrad
    April 4, 2009

    I’m with Greg here. There’s no need to use two words when one will do, or a ten dollar word when a nickle word gets the meaning across. It’s a bad habit that cuts across disciplines: academia, business, newsertainment. It’s why business people utilize something instead of just using it. It’s why the traffic ‘copter warns us of an “accident situation” instead of just telling us that there is an accident. At least we know what those minor foibles mean. This paper is a doozie!

  6. #6 Katkinkate
    April 4, 2009

    It’s like the writers just bought a new thesaurus and felt they had to get their money’s worth. Or alternatively, one of the key writers is a bureaucrat and has swallowed the ‘policy-speak’ or ‘military-speak’ language meme (always keep your sentences sufficiently blurry to allow multiple interpretations and use lots of in-words like ‘paradigm’) and tried to translate it into ‘science-speak’.

  7. #7 Doug Alder
    April 4, 2009

    As a former English major I have to say that was simply painful to read. Aside from that, when you mentioned the drop in sea level Greg it made me curious regarding the effect the resultant increased salinity had on sea life, and if it caused and large extinctions of species that could not handle the increased salinity. That’s a lot of water to remove so salinity must have increased considerably during the ice ages. Ah well off to Google to look into this :)

  8. #8 Larry Ayers
    April 4, 2009

    Great deconstruction of a jargon-laden abstract, Greg! William Zinsser’s “On Writing Well” deals with many of the issues you raise.

    “With a match.” I loved your succinct reaction, Stephanie!

    I’m an amateur student of English writing styles. I enjoy seeing bad writers being taken to task for their crimes against the language!

  9. #9 Greg Laden
    April 4, 2009

    I don’t think the salinity increase was very large. It sounds like a lot of water taken out of the ocean, but it was a small percentage of what was in there.

  10. #10 Doug Alder
    April 4, 2009

    Greg – I realize that the amount of fresh water removed is but a drop in the ocean (G) nevertheless It must have altered the salinity somewhat and I wonder if that had an effect on the NADW thermohaline pump. this is a look at some of that. Still trying, as a non-scientist, to work my way through that page but it’s interesting ( not well composed though)

  11. #11 Mikewot
    April 5, 2009

    A guide on how to write good:

    1. Always avoid alliteration.
    2. Prepositions are not words to end sentences with.
    3. Avoid clichés like the plague — they’re old hat.
    4. Employ the vernacular.
    5. Eschew ampersands & abbreviations, etc.
    6. Parenthetical remarks (however relevant) are unnecessary.
    7. Parenthentical words however must be enclosed in commas.
    8. It is wrong to ever split an infinitive.
    9. Contractions aren’t necessary.
    10. Do not use a foreign word when there is an adequate English quid pro quo.
    11. One should never generalize.
    12. Eliminate quotations. As Ralph Waldo Emerson once said, “I hate quotations. Tell me what you know.”
    13. Comparisons are as bad as clichés.
    14. Don’t be redundant; don’t use more words than necessary; it’s highly superfluous.
    15. It behooves you to avoid archaic expressions.
    16. Avoid archaeic spellings too.
    17. Understatement is always best.
    18. Exaggeration is a billion times worse than understatement.
    19. One word- sentences? Eliminate. Always!
    20. Analogies in writing are like feathers on a snake.
    21. The passive voice should not be used.
    22. Go around the barn at high noon to avoid colloquialisms.
    23. Take the bull by the hand and avoid mixed metaphors — even if a mixed metaphor sings, it should be derailed.
    24. Who needs rhetorical questions?
    25. Don’t use commas, that, are not, necessary.
    26. Do not use hyperbole; not one in a million can do it effectively.
    27. Never use a big word where a diminutive alternative would suffice.
    28. Subject and verb always has to agree.
    29. Be more or less specific.
    30. Placing a comma between subject and predicate, is not correct.
    31. Use youre spell chekker to avoid mispelling and to catch typograhpical errers.
    32. Don’t repeat yourself, or say again what you have said before.
    33. Don’t be redundant.
    34. Use the apostrophe in it’s proper place and omit it when its not needed.
    35. Don’t never use no double negatives.
    36. Poofread carefully to see if you any words out.
    37. Hopefully, you will use words correctly, irregardless of how others use them.
    38. Eschew obfuscation.
    39. No sentence fragments.
    40. Don’t indulge in sesquipedalian lexicological constructions.
    41. A writer must not shift your point of view.
    42. Don’t overuse exclamation marks!!!
    43. Place pronouns as close as possible, especially in long sentences, as of 10 or more words, to their antecedents.
    44. Writing carefully, dangling participles must be avoided.
    45. If any word is improper at the end of a sentence, a linking verb is.
    46. Avoid trendy locutions that sound flaky.
    47. Everyone should be careful to use a singular pronoun with singular nouns in their writing.
    48. Always pick on the correct idiom.
    49. The adverb always follows the verb.
    50. If you reread your work, you can find on rereading a great deal of repetition can be by rereading and editing.
    51. And always be sure to finish what

  12. #12 Greg Laden
    April 5, 2009

    Doug: The average depth of the ocean is 3800 meters, and the maximum drop was 200 meters. If the ocean was a straight sided waterglass, that would be a half of a percent, but since that top 200 meters covers continental shelf, we can add a 50% fudge factor and figure the difference to be just under 1%.

    For some systems, 1% is not much, for others, it is a lot.

    In the case of the ecology of salt water organisms, salinity matters but most organisms are adapted to a range that is more than a few percent.

    The THP – which is all about currents in the ocean – is a big deal and there is no doubt whatsoever in my mind that the sea level drop would matter, and that the ice matters here. The ice matters in part because when it melts you get large scale fresh water flushing events, where a Lake Superior size bucket of fresh water suddenly covers a big piece of the ocean somewhere, like in the North Atlantic or the Gulf of Mexico. That will always effect currents that are driven by heat/cooling or salinity. Plus, the shape of the oceans, though not of the basins change. During low sea level, there really was not much of a Gulf of Mexico, and the entire Caribbean was dry land (well, most of it). Have you ever flown over the Caribbean? All that light blue water would be woodland/jungle/whatever.

    So, yea, it would make a huge difference. I’m not sure how much the exact overall amount of salt matters, but the distribution of salt would be different.

  13. #13 mark
    April 5, 2009

    In recent Earth history, temporally dynamic chemical weathering fluxes from the continents are an inevitable consequence of periodic glaciations.

    I don’t find this difficult to understand (the amount [flux] of elements [chemical weathering, as opposed to mechanical weathering] transported to sea varies over time because of glaciation). But that’s not news. Probably the best way to improve the paper would be to judiciously shorten it, deleting as much “old news” as possible.

  14. #14 Russell Blackford
    April 5, 2009

    Um, Greg, don’t you mean 5 per cent rather than O.5 per cent? Or a “fudged” 10 per cent rather than 1 per cent? I.e., 200 is about a 20th of 3800, i.e. 5 per cent. It’s not a 200th.

  15. #15 Greg Laden
    April 5, 2009

    Right. Multiply everything I say by ten.

    This is still within normal variation in the ocean.

  16. #16 Greg Laden
    April 5, 2009

    I don’t want to give the impression that this is not important (salinity changes). This is actually the subject of a lot of research and it is quite interesting. But I do want to say that the total amount of salinity owing to glacial trapping is less of a factor than many other factors.

    For instance, the glacial patern of circulation fails to bring a lot of less saline water to the northern regions (the tropical ocean is less salty than the temperate and subarctic ocean owing to the influx of freshwater from tropical rain). So the subarctic and temperate zone is saltier for this reason during glacials, PLUS the presumed shift because of trapping of fresh water in ice.

    THEN, meltwater events quickly convert somewhat salty surfaces in the ocean to very fresh surfaces. So not only does a glacial period have this capacity for major fresh water influx, but that is happening against a somewhat saltier background. That has to have huge effect on both the ecology and the circulation systems.

    And there is much more going on than that having to do with evaporation, other aspects of rainfall patterns, basin-level circulation, etc. etc.

  17. #17 Jeffrey
    April 5, 2009

    Rivers are the dominant source of many elements and isotopes to the ocean.

    Oh, and by the way, isotopes are elements… no need to use the extra words.

    I think that the author means that rivers are a source of elements that wouldn’t be in the ocean otherwise, and isotopes that wouldn’t be in the ocean otherwise, even if other isotopes of the same element would be. It’s a necessary distinction, but poorly articulated.

  18. #18 Peter Rivard
    April 6, 2009

    It’s fun to rag on the author of the abstract for his seemingly opaque style, but bear in mind that s/he’s writing for people who read this kind of language all day long and understand it easily. And in particular fields, words that may seem pompous in everyday speech carry particular meanings that their translations into “plain English” don’t. Further, in the choice of language, the author may be tying his or her arguments into a larger conversation that’s usually expressed in such language; words that may be clunky to an outsider may be sending a clear signal to the intended reader of where the article fits within the current literature of the field–relation to a particular subfield or current question, analytical perspective or method, even possible biases.

    There’s a lot of bad writing in science and a lot of good to be done by knowledgeable editors cleaning it up, as Dr. Laden does. A reader who isn’t an expert in a field still has a right to an opinion on a work of science–and may in fact have quite valid points to make–but needs to keep his or her own level of knowledge and experience in mind: if I can’t make heads or tails of special relativity, I have to consider that maybe it’s just me not getting it rather than Einstein having messed up (see the previous poster who’s forgotten so much of high school that he thinks “element” and “isotope” are synonyms and yet feels qualified to correct a peer-reviewed article).

    Here’s a suggestion for Dr. Laden: You challenged people to rewrite some bits of the abstract. How about showing us some of the results, pointing out where people got it right and where people ended up losing or changing important information? It’d be a great way to show how discourse varies across disciplines, to prod some scientists toward clearer communication, and to remind science readers to keep an open mind–that sometimes there’s more going on than we realize.

  19. #19 Peter Rivard
    April 6, 2009

    Ooops, thought the “elements and isotopes” bit was from a previous poster; didn’t realize it was from Dr. Laden, who obviously knows a lot more about this stuff than I do. I failed my own “benefit of the doubt” standard.

    But…and I am a layperson here…”the loss of the elements and isotopes through hydrothermal and sedimentary exchange” made sense to me. When you’re talking about elements you’re talking about elements relative to other elements, so some elements are getting selectively removed through those mechanisms, affecting the balance of elements: perhaps you end up with more or less tungsten relative to iron than you started with. When you’re talking about isotopes, it’d make sense to talk about them relative to other isotopes, I’d assume of the same elements. So these mechanisms are also affecting the isotopic balances, meaning, say, you get more or less 16^O relative to 18^O. So when I read that, it seemed to me that he WAS writing about two different things: both the elemental AND isotopic balances are being changed through these loss mechanisms. Maybe if I read the rest of the paper I’d see the author didn’t mean that and was in fact using them to mean the same thing–but that’d just be so pointless that it didn’t occur to me in reading the abstract (it’d go beyond bad style into just plain “goofy”).

  20. #20 Greg Laden
    April 6, 2009

    Peter: For the abstract, it is sufficient that isotopes means elements, and they could have just said elements. And, this is my field and I found it totally badly written. But of course you bring up a lot of good points. One thing I’ve been watching is PLoS, where a so called “author’s summary” which appears to be the more intelligible version for the broader audience is included. Some day I’m going to try to classify them by how well done they are.

  21. #21 Nathan Myers
    April 6, 2009

    The increased salinity of the newly-flooded coastal regions has to have had a greater effect on tetrapods than on sea life. Our own ancestors living in the Mediterranean basin or the Engish Channel must have found it hard to sleep under the new conditions.

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