…because I was able to tell someone who works on ‘process B’ that someone else who works on ‘process A’ (of which ‘process B’ may be a side-effect) is going on a cruise in about a month from now, so maybe they could get some samples out of this by contacting the PI. ‘Process B’ has recently been suggested as a possible outcome of ‘process A’, and measuring it in as many different environments and under different conditions as possible is crucial to finding out more about its implications.
As small and insignificant as they may be, I love putting fleas in peoples’ ears like that and spread the wealth. So, since I’m unlikely to ever be able to do anything with it myself, because I’m not risking a fantastic career in academia by saying something silly or unlikely, and prompted by Robert’s comment, I’ll tell you about my most off-the-cuff science idea.
When I was on that cruise I mentioned before with Ken Smith and his colleagues in late 2005, I had the chance to look at some fluffy material they found attached to certain areas of the underside of an iceberg. Most of the stuff was phytoplankton, but I swear I saw some benthic foraminifera in there. I couldn’t follow up on this because my job on that cruise was being the boss-mam of the support staff, but the reason I know that I wasn’t imagining it is that I showed a microscope picture to a benthic ciliate expert after the cruise, and she was pretty sure she also saw benthic ciliates in the stuff. ‘But benthic foraminifera live on the seafloor, so how should they be able to get there?’ you shout, and you’re right. At first sight, it does seem unlikely that they should be able to somehow colonize those fluff-bits on the free-drifting iceberg, floating way above the seafloor. Then again, it may be possible.
As icebergs break free of glaciers and float around, they often scrape along large areas of shallower seafloor – this is called ‘iceberg scouring’. The effects of this have been looked at in some detail (note: <-this is quite a random collection of references on the subject).
Deep sea benthic foraminifera are distributed very widely, and some species have been shown to be ‘bipolar’ using molecular tools, providing some support for the hypothesis that small eukaryotes are distributed globally. However, dispersal modes of foraminifera have only been looked at in very few studies; one proposed the passive transport of propagules. Very wide dispersal via flagellated gametes produced during asexual production seems unlikely, as these have tiny energy reserves and wouldn’t last long swimming around (see e.g. page 2167 of previous link). So how did benthic forams get everywhere?
You can guess my idea by now: I suspect that at least some benthic foram species could have been hitchhiking on the bottom of icebergs, and I think it would be interesting to look at icebergs as possible vectors for foram distribution. Of course, there are other things to consider: for example, such species would have to be tolerant to significant changes in salinity (the iceberg giving off fresh water during melting). If the iceberg melted over deep water, the forams would have to stay intact while sinking to the seafloor – but if they’re in fluff or phytodetritus, chances are they’d make it to the seafloor quick enough. Icebergs would be a perfect transport mechanism: during a couple of meltdowns over the last tens of thousands of years, icebergs floated way outside of the range we see today (all over the place, really), as shown by ice-rafted debris and scour marks.
Of course, if anyone was ever going to look at this, they’d face several serious logistical problems: they’d have to find an iceberg that has fluff attached to it, get the fluff off (for example using an ROV) and back to the ship in one piece.. and finally, be lucky enough to find forams in that fluff. So really, all that right there would make this pretty much an unfundable project – too many uncertainties (sigh), and too expensive (you need an icebreaker and a powerful ROV for starters).
So there you go. My crazy idea. What’s yours?
This post was first published (under the title “I felt very self-satisfied last week..”) on Nature Network, which has since been discontinued. The post has been moved to SciLogs, where you can also read the comments made at the time.