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”).

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.

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.

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.

This is still within normal variation in the ocean.

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.

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.