OHHHHHHHHHHHHH….Who lives in a carbonate shell under the sea? Forams. Forams do.
I work with forams (but really the forams are working for me) so that I can reconstruct some pretty crazy cool paleoceanography. They’re not as sexy as t-rex (big head, little arms) or as terrifying as the giant North and South American terror birds (google it, they were terrifying), but they play a major role in some of the coolest geology every done and obviously, in the science being done by my advisor and me now. Forams are pretty awesome, and so of course I had to share.
The live ones
Forams are little critters (protists if you want to get specific about it) that live (and have lived) all over the world’s oceans. Forams are generally quite small, but some can get as large as tens of centimeters in length, and can live anywhere from a couple weeks to a couple years. There are around 4,000 living species of forams in the oceans today, but only 40 of those species get to spend their gloriously short lives floating around in the water (this is what we call planktic foraminifera). The rest of these guys spend their lives living in or on ocean sediments, rocks or even plants at the bottom of the ocean (this is what we call benthic foraminifera). Many species are pretty picky about their habitats (the shoe has to fit, right?), but they can be found pretty much anywhere.
What does something that small eat, you may ask? Well, some forams eat algae that grow inside their shells (symbiosis!) and others eat organic molecules or even brine shrimp. Forams “catch” their food with their whisker looking pseudopodia, which they also use to float around in the water. And since I know you’re dying to watch a foram feed on a brine shrimp… I found a fancy video by a famous foram scientist, H. Spero, for you to do just that (really, it’s awesome though…so watch it).
Very little is understood about live foraminfera. Even species that are relatively well studied show such a variety of characteristics that makes it difficult for scientists to determine a pattern in characteristics. In [FUN] fact, scientist have never been able to successfully reproduce a foram in the lab. We can catch them. And feed them. And keep them alive. But we can’t make them reproduce. This is a huge barrier for understanding the mechanisms behind shell creation, and there’s obviously still a lot to learn.
The dead ones
Live forams are cool and all, but I care more about the dead ones. To get really specific, I care about the once floating dead ones that lived between 29,000 and 14,000 years ago whose shells have been preserved in marine sediments in the equatorial Pacific. These lucky bastards, lived through some very important climate variability in the recent geologic past and their glorious carbonate shells recorded it all! I suppose I owe these little buggers a great big thank you, because without them there would be no PhD for me.
Besides being useful for the geochemical climate information recorded in the shells of long dead bugs, forams are also extremely useful for determining relative ages of marine sediments. Different species are found at different times, and as I mentioned before, they are found in marine sediments from around the world making forams a fantastic universal tool for relative dating. This is why oil companies love forams…and love people who love forams. Oil formed at specific times in Earth’s history. So when someone who loves forams can tell oil companies when their sediments contain forams from the oil window age–money gets made.
Dead forams (well, really their shells) have also been used to reconstruct past geography and ecology. Specific species are found in specific geographic and ecological “niches,” and therefore can be used in the geologic record as a proxy (i.e. recorder) for those conditions. Scientists can then pick forams from ancient marine sediments, and tell a story about how a single location has evolved through time with respect to sea level, temperature or even acidity.
So yeah, forams are cool(er than t-rex and terror birds…and PhD students stuck in a basement office)
Photo 1: http://collections.nmnh.si.edu/media/?i=10419480
Photo 2: http://www.geo.uni-bremen.de/forschung/bilder/106-2big.jpg
Photo 3: http://www.sjvgeology.org/geology/fossils/forams.jpg
Photo 4: https://carriekravetz.files.wordpress.com/2010/01/starsand2.jpg?w=460&h=333