Did you know, 450 million years ago, Iowa lay near the equator under the Iapetus Sea? Standing at a couple inches to as much as 10 feet deep, with hot, constant sunshine and high salinity just like Red Sea today, Iowa was a very different environment than what we experience today.
The river bluffs that surround us today are actually old coral reefs made up of millions of microbial organisms, and even fossils of larger creatures, such as Endoceras Cephalopod. A squid-like creature that cruised the ocean during the Middle Ordovician Period about 450 million years ago, Endoceras was a real “sea monster” when it was alive. It was very large (up to 15 feet, maybe even 30 feet!), could jet through the water very fast, had long suckered tentacles like an octopus, could deliver a powerful and possibly poisonous bite, ejected a cloud of black ink to confuse other predators, and ate smaller sea creatures. It predates the dinosaurs of “Jurassic Park” fame by something like 375 million years and was almost as big a threat underwater. Cephalopds came in cone shapes, spiral, and whipped cream shapes and the many species could be as tiny as your pinkie finger or as long as a telephone pole. Broken fragments of these beautiful fossils have been found at Spring Grove, Minnesota, Waukon, Iowa, and Liberty Pole and Fennimore, Wisconsin.
Another carnivorous cephalopod that lurked in northeast Iowa’s tropical seascape is known as the Gonioceras. Attaining a length of perhaps a couple of feet, Gonioceras was a bizarre predator living inside a flattened, cone-shaped shell. Scientists think that Gonioceras may have been an ambush predator – lying in wait on the muddy sea bottom, then darting out and seizing any prey that came within reach of its tentacles.
Stromatolites are another organism that make up most of northeast Iowa’s picturesque bluffs. Produced by the activity of ancient cyanobacteria (cyan stands for green-blue, bacteria), the layers of coral were produced as calcium carbonate precipitated over the growing mat of bacterial filaments. This process still occurs today; Shark Bay in western Australia is well known for its stromatolite "turfs" rising along its beaches. Cyanobacteria are also tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria photosynthesizing during ancient eras. Before that time, the atmosphere had a very different chemistry, unsuitable for life as we know it today.
Join us this Friday at 4:00 pm, as Dan Jackson, a concerned amateur naturalist who grew up around La Crosse, WI, gives a fun and informative introduction to the insect order Odonata. It includes a section on the biology and life history of this order as well as their identification. Also, our Friday Night Live farmers markets kick off from 4:00 - 7:00 pm on Fridays, starting May 22nd until October 9th.
All information is provided by Phil Burgess, self-taught Driftless Area geology expert and Driftless Area Wetlands Centre consultant. The Driftless Area Wetlands Centre in Marquette, Iowa is working toward its non-profit status and we are currently funded by the City of Marquette, grants, and donations. We are open from 11:00 – 4:00, Tuesdays – Saturdays. We always have lots going on, so check us out on Facebook, our website, or call us at (563) 873-3537.
Enjoy the Outdoors! It’s always free!