National Academies Press: OpenBook

Effects of Past Global Change on Life (1995)

Chapter: Ecology of Modern Planktonic Foraminifera

« Previous: INTRODUCTION
Suggested Citation:"Ecology of Modern Planktonic Foraminifera." National Research Council. 1995. Effects of Past Global Change on Life. Washington, DC: The National Academies Press. doi: 10.17226/4762.
×
Page 211

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

BIOTIC RESPONSES TO TEMPERATURE AND SALINITY CHANGES DURING LAST DEGLACIATION, GULF OF MEXICO 211 associated with variations in equatorial divergence. Other studies have examined the response of both planktonic and benthic biota. Planktonic and benthic foraminiferal assemblages were affected by salinity and circulation changes in the Red Sea and the Gulf of Aden (Locke and Thunell, 1988) and in the Mediterranean (Thunell et al. , 1977; Muerdter et al., 1984). Pedersen et al. (1988) documented the response of benthic foraminiferal populations to deglacially induced changes in surface productivity in the Panama Basin. Radiometrically dated, high-resolution work in some areas has produced highly detailed faunal and isotopic records of deglaciation. Oxygen isotopic and planktonic foraminiferal assemblage records from the Sulu Sea (Linsley and Thunell, 1990; Kudrass et al., 1991) and the Gulf of Mexico (Kennett et al., 1985; Flower and Kennett, 1990) illustrate the sensitivity of planktonic foraminifera to rapid oceanic environmental change and document the expression of the Younger Dryas cooling event. Labracherie et al. (1989) showed coherence between faunal and oxygen isotopic changes in the Indian sector of the Southern Ocean and documented a brief return to near-glacial temperatures from ~12 to 11 ka. Studies such as these integrate high-resolution faunal and isotopic evidence to define in detail the character of rapid deglacial environmental and biotic changes. The integration of Quaternary faunal and geochemical records from deep-marine sequences has demonstrated the extensive influence of North Atlantic oceanography in disparate areas of the world's oceans and has led to the concept of a "conveyor belt" mode of circulation (Broecker et al., 1985). In this model, the Quaternary ocean circulation system is paced by the formation of North Atlantic deep water (NADW), which flows as a deep current through the South Atlantic Ocean, is entrained into the circumpolar current, and flows through the Indian Ocean to the Pacific where it upwells, eventually returning to the North Atlantic via surface currents. A circuit is completed, on average, every 1000 yr. Turning the conveyor belt on or off may have controlled oceanographic and climatic changes in the late Quaternary, which influenced the Earth's biota. Ecology of Modern Planktonic Foraminifera The need to interpret fossil planktonic foraminiferal assemblages has fueled interest in the biology and ecology of modern forms. Modern planktonic foraminifera are found throughout the oceans, with diversity increasing toward the tropics. Effectively only one species is found in polar oceans, whereas about 30 species inhabit the tropics. The geographic distribution of distinctive assemblages, which follows major water mass boundaries, is shown for the North Atlantic Ocean in Figure 12.1. Plankton tow work (for example, Bé and Tolderlund, 1971; Tolderlund and Bé, 1971; Fairbanks et al., 1982) has shown that most forms live in the mixed layer (upper 100 m), Figure 12.1 Distribution of planktonic foraminiferal assemblage provinces and ocean stations in the North Atlantic (from Tolderlund and Bé, 1971).

Next: RESULTS AND DISCUSSION »
Effects of Past Global Change on Life Get This Book
×
Buy Hardback | $65.00 Buy Ebook | $49.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

What can we expect as global change progresses? Will there be thresholds that trigger sudden shifts in environmental conditions—or that cause catastrophic destruction of life?

Effects of Past Global Change on Life explores what earth scientists are learning about the impact of large-scale environmental changes on ancient life—and how these findings may help us resolve today's environmental controversies.

Leading authorities discuss historical climate trends and what can be learned from the mass extinctions and other critical periods about the rise and fall of plant and animal species in response to global change. The volume develops a picture of how environmental change has closed some evolutionary doors while opening others—including profound effects on the early members of the human family.

An expert panel offers specific recommendations on expanding research and improving investigative tools—and targets historical periods and geological and biological patterns with the most promise of shedding light on future developments.

This readable and informative book will be of special interest to professionals in the earth sciences and the environmental community as well as concerned policymakers.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!