MARINE GEOLOGY AND GLACIOLOGY
DIATOMS, OVERVIEW

	Diatom workers team Emily Bradshaw egb@geus.dk Karin Gutfelt Jensen kgj@geus.dk
Stephanodiscus alpinus/medius ] - a freshwater diatom

Diatoms are microscopic unicellular algae, either circular (centric) or linear-elliptical (pennate) in shape. They are found in a wide range of aquatic habitats and exist in many forms including benthic (bottom living), epiphytic (attached) and planktonic (free living). Diatoms are common in the deep ocean, lagoons, estuaries, lakes and rivers.

The living diatom has a siliceous (made of silica) shell or frustule which can be found preserved in freshwater and marine sediments when the diatom cell settles out of the water column.

Diatom species are extremely diverse in form and ecology and the community composition of diatoms found in aquatic systems is strongly influenced by environmental variables (e.g. water chemistry). In this way, a diatom assemblage preserved in sediments can provide a record of environmental change through time.

Diatomists in the department have interests in freshwater, coastal and marine environments and on seasonal, decadal, century and Holocene time-scales. Diatom projects include:

• The Sarup Sø Project
• Holocene paleo-hydrographic changes in Greenland coastal waters and fjords, and possible implications for human settlement

• British Micropalaeontological Society ( BMS
• Paleolimnology & Diatom Home Pages (Biology Department, Indiana University)
• The International Nannoplankton Association (INA)
• Diatom Home Page (Biology Department, Indiana University)
• Environmental Change Research Centre ( ECRC, UCL
• Paleoecological Environmental Assessment and Research Lab PEARL Department of Biology, Queen's University

Emily Bradshaw - egb@geus.dk
Feel free to send e-mail for more information.

Edited by:
Niels E. Poulsen - nep@geus.dk