Foraminifera have been found in sediments all over the world, in every ocean and throughout geologic time. Forams for short, these single celled organisms with calcareous shells or in some cases shells made of silica and organic material belong to the Protista Phylum. Forams are found in sedimentary rock dating back to the Cambrian Period and are living in our environments today. Many foram species are benthic creatures (bottom dwellers) and live a few inches above the ocean floor and are microscopic in size. To get a good photograph of a typical foram it would be necessary to magnify it 100x under a binocular microscope as shown above. Most Forams are no typically bigger than the period at the end of this sentence. Forams are identified and classified primarily by their composition and morphology (shape and distinctive features).
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Like sea shells most forams have calcareous (calcium carbonate – CaCo2) shells composed of calcium carbonate and in some cases Silica (Si02). These microscopic organisms eventually die in the trillions every day and have done so throughout geologic time. They die and sink to the bottom of a body of water where they accumulate in great quantity and tonnage. They eventually form the bulk of the ocean bottom sediment. Over eons this material accumulates becomes exposed to dry land and can be drilled down to extract oil deposits. A great example of an area once covered by shallow seas is Texas. Yes that Texas where some of our oil is extracted and a place where many millionaires have been made.
Amongst the foram sediment is organic and inorganic sediment from windblown dust, natural soil, pollution in the form of industrial particulates from cars, factories and the like (carbon-soot) and other minute airborne pollutants. Eventually these natural and present day particulates sink to the bottom of the ocean, layer upon layer eon after eon. Huge microfossil accumulation over millenium result in sometimes a white soft substance called Chalk, as in the “White Cliffs of Dover”. This is where a huge accumulation of this material is deposited and over the eons and eventually becomes encased in the layers above. This oozing sediment over time, time and more time becomes compressed due to the pressure of the ocean depths as well as the weight of the overlying material. Again over time with foram skeletal material, pressure and the organic makeup of forams produced over millions of years and millions of tons of this oozy sediment slowly forams into petroleum deposits squeezed between the minute spaces of the now solidified “rock”.
Foram microfossils are known to have existed since the Cambrian Period. The compositions of marine sediments are mostly made up of these benthic creatures. These creatures are responsible for reef building in the distant past but are responsible for reef building and the health of reefs today as well. The presence of these creatures also maintains the health of the reef. They are at the starting line of the food chain for all living things in our oceans. They are important to our economy from our ancient past to our present day. If it were not for forams what would the ancient Egyptians have used to build the Great Pyramids!
Today we use foram limestone for buildings and building materials as did our ancestors throughout human history. We have built our cities from materials mostly limestone composed of forams and larger fossilized creatures. If you ever have been to New York City, where I was born and raised, most of the older high-rise buildings constructed from 1939 to 1969 have magnificent limestone slabs either as part as their facade or on their lobby floors. Looking and touching sides of buildings, lobby floors and other structures with wonderful and clearly visible fossils almost got me arrested! That is a story for another time. Let me know if you want to hear the long version?
Due to the hardness of the foraminifer’s exoskeletons they are readily preserved in the fossil record. Also due their proliferation and tiny size (usually below 1mm) there can be literally thousands of individuals and many different species accumulated in one cubic centimeter of sediment which is about the size of a sugar cube.
Foraminifera come in many different shapes from simple single chamber species to elaborate and beautiful forms with their chambers arranged in various different patterns and combinations.
Also if you never have seen forams under magnification you would probably say they look like larger versions of sea shells, nautili and other bivalves living today. Nature keeps successful designs of creatures going. When nature gets the evolution of a species correct for a particular earthly environment then those species tend to exist for millions of years. If it’s not broke do not fix it as the saying goes.
Deep sea species
Foraminifera are found in the deepest parts of the ocean such as the Mariana Trench, and the Challenger Deep, the deepest part known. Due to the extreme pressures at these depths, the
forams possessing calcium carbonate exoskeletons are soluble in water. At these great depths some Foraminifera found have exoskeletons of organic material. This organic soup is comprised of millions upon millions of tons of forams and other organic and non-organic material. Over geologic time this oozing organic soup as mentioned earlier can form into a petroleum deposit under certain geologic conditions and over long geologic periods of time.
The deep sea drilling efforts throughout the world and for the purpose of petroleum exploration have significantly been have contributed to the microfossil library. The petroleum industry has been bringing up sediment cores bearing foram fossils since the 1960’s up until today. This industry has only become more sophisticated over the years and is in itself one of the most important industries for continuous study and research of foram identification, classification and study. The abundance of sediment cores in different locations of the world has afforded scientists to study various species of microfossils and bench mark some species as index fossils. These index fossils date back to the specific periods in geologic history and could point the way toward future petroleum deposits. Also the vast amount of information and data gathered from these deep sea cores has enabled scientists to record and document evolutionary processes that have taken place over millions years.
In the course of Earth history, larger Foraminifera have been replaced by other species. These evolutionary processes make the larger Foraminifera prone to be fossilized due to the mass die offs in a slightly changing deep ocean setting and making them an excellent index fossil for the Mesozoic and Cenozoic Periods. In closing forams are doubt an important part of our past and certainly is part of our future. Should we protect our environment? Absolutely! From the microscopic life forms to our endangered species we must be aware. Check out our other fossil sections for information, fun things and news as we progress through the geologic time scale on Facts About Fossils.
