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340 Ocean Detective: Debbie Wall-Palmer
Submitted by Teresa Greely on Fri, 03/23/2012 - 23:58
Enjoy meeting 340 Ocean Detective Debbie Wall-Palmer who has created a PHOTO Story to share her research while aboard the JR.
Hello everyone, I'm a PhD student in the final year of a PhD in micropalaeontolgy at Plymouth University in the United Kingdom. My PhD research looks at the effects of past ocean acidification and climate change on pteropods (planktic snails) and related fauna in the fossil record. Keep reading to learn more about sea butterflies and sea elephants!
This is what a micropaleontologist sees when they look down their microscope!
There are many different types of organisms in our samples which represent what has been living in the ocean in the past. This sample was taken from just below the sea floor, so it represents the organisms living in the ocean right now! In this photo you can see planktic foraminifera (living in the water column), benthic foraminifera (living on the sea floor), planktic and benthic gastropods (snails), pieces of sponge, called spicules and a bivalve. The scale in the bottom left corner is 1 mm.
On the ship my job is to look at planktic foraminifera, however, when I'm back in the UK, my research involves studying pteropods and heteropods. Pteropods and heteropods are planktonic snails that have evolved wings! They live their entire lives swimming around at the surface of the ocean, catching smaller plankton in nets of mucus. The pteropods are known as sea butterflies because they flap their wings to swim. The heteropods also have wings, but are known as the sea elephants because they have a long trunk! Some pteropods don’t have shells - we don't see these in sediments because they leave no fossil. Only pteropods that have shells leave a fossil for us to study. The pteropods in this picture are called Styliola subula.
This is one of my favorite species of pteropod it is quite common in the Caribbean. It is called Diacria quadridentata. The shell of this species is quite large, about 2 mm in length. Although pteropods are snails, their shells come in a variety of shapes!
Pteropods make a shell of aragonite, which is very easily dissolved when sea water pH becomes slightly acidic. This makes them useful for working out at what water depth dissolution occurs on the sea floor. Generally, the deeper the water, the more dissolution occurs. In this photo you can see two specimens of the same species (Limacina inflata). The one on the right is in good shape, it looks strong and shiny. The one on the left however, has been dissolved, removing a large part of the shell and the shiny surface layer. Because their shells are so easily dissolved, living pteropods are currently under threat due to changes in ocean chemistry related to climate change.