Paleoclimatology is the study of the past climates and oceans of the world. Through the use of proxies, paleoclimatologists can reconstruct different climates for a specific region, an ocean, or estimate the global temperature and CO2 concentrations at different points in time. It is paramount that we understand how Earth’s oceans and climates responded to climate changes in the geologic past, such as abrupt warming events and glaciations, so we can predict and understand how these systems will react to extreme warming now and in the future. With this knowledge, we can predict where sea level rise will impact coastal communities the worst, how global warming will influence crop growth, and budget for natural disasters that will become more frequent and severe in the future.
There are several ways paleoclimatologists study past climate change events. One way is through the fossil record of marine plankton that create tiny calcite shells. These shells record the chemistry of the ocean at the time the organism created it. When the plankton dies, the shell falls to the seafloor and eventually becomes part of the geologic rock record. By extracting the tiny plankton shells from rocks and ocean sediments, we can analyze the calcite for stable isotopes to help gain an image of what the Earth’s climate was like millions of years ago.
In the ‘Science Bytes’ blog, Adriane will explain and share what she does using a specific type of marine plankton to reconstruct climate from millions of years ago.
What fossil group do I study?
Adriane studies an extant (still alive) group of marine plankton called foraminifera. Foraminifera (from Latin, meaning ‘hole-bearers’) are single-celled protists that live at the top of the water column (planktic foraminifera) and at the bottom of the ocean (benthic foraminifera). Foraminifera that secrete a calcite shell have been around since the Jurassic, and are rather abundant in rocks and in the oceans today.
What do I do with these fossils?
Foraminifera are very useful for several different reasons. First, they secrete calcite shells, which are made of a calcium (Ca) and carbonate (CO3) ion. The carbonate ion is important to paleoclimatologists because we use the isotopes of oxygen (O) and carbon (C) in the carbonate ion to tell us about ice volume, temperature, productivity (amount of nutrients in the waters), and deep sea circulation.
Secondly, there are several different species of foraminifera, and each species is happy in a certain temperature of water. This means that some species may only be found in cold waters, like those found in more polar regions, and others are happy in warm waters, such as those near the equator. By mapping the occurrence of different species in deep time, we can reconstruct where the general location of climate belts were, and how those changed through time. There are also lots of other cool things for which foraminifera are used, but that will be discussed in the blog sections of this website.
Specifically, Adriane is investigating how two Pacific Ocean western boundary currents, the Kuroshio Current and Extension in the northwestern Pacific and the Tasman Front in the southwestern Pacific, developed from 15 million years ago to today. She is also researching how the currents responded (did they shift north or south? did they increase or decrease the amount of water they transport?) to major climate change events (cooling and warming) throughout this time interval. Western boundary currents are important moderators of weather and climate patterns, as they bring lots of heat and moisture from the equator to higher latitudes. In addition, she is also studying the evolution and extinction patterns of planktic foraminifera (species that live in the upper water column) across major climate shifts in the past.
Evolutionary paleobiology is simply the study of evolutionary processes on ancient life. It takes concepts used in biology and applies them to extinct forms. There are many different ways to study evolutionary paleobiology. Jen will discuss the methods she uses to examine a group of extinct (no longer living) echinoderms (sea stars, sea urchins, etc.) on the ‘Science Bytes‘ blog. She will also discuss and highlight some important findings from her work!
There are some some very basic things that drive the study of evolution in deep time. Consider things that you see every day, patterns in nature. Certain trees are only found in high latitudes but very different trees are found near the equator. Logically, this separation should be seen in the past as well. We can consider the distribution of environments, organisms, and even body forms through time. These patterns that we can observe in nature change through time and we can travel through time to examine them through the fossil record!
What fossil group do I study?
Jen studies an extinct echinoderm group called blastoids. Echinoderms are still alive today (extant) and include sea stars, sea urchins, sea cucumbers, brittle stars, and sea lilies. There are those five main groups alive today but upwards of twenty groups that are now extinct. Echinoderms preserve very well through time because their skeletons are very chemically stable. Blastoids come in many shapes and sizes, which make them very fun to study. In addition to having a very well-preserved skeleton, blastoids have a really well-sutured body. Unlike many echinoderms, blastoids have a body that hold together very well – it’s resistant to normal things that would make other echinoderms fall apart.
What do I do with these fossils?
Jen usually starts her research in museum collections. This allows her to examine many specimens all at once! Examining museum specimens allows researchers to view the very small changes from specimen to specimen and think about how this affects the organisms daily life. While in the collections, researchers can also develop a set of characters that defines specific organisms. Each character describes an aspect of the organism’s and can usually (not always) be related to more blastoids. Jen uses all of this collected data to test and assess blastoid relationships. Blastoids that share similar features are likely more closely related to each other than they are to ones that have different features. This helps us understand the evolution of the group.
Jen also uses advanced imaging techniques to see inside specimens. These imaging machines take hundreds to thousands of slices through specimens and you can reconstruct the outside and the inside (if you find anything cool, like a gut, gonad, or respiratory structures)! The other big part of her current work is to better understand how these organisms respired (kind of like how humans breathe). This involves using old and new types of data to examine the insides of blastoids. It’s really exciting work!
If you are interested in learning more about either of our fossil groups, click on the links below!