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Ooze Clues Diatom Ooze Written by: Lisa Ayers Lawrence, Virginia Sea Grant, Virginia Institute of Marlne Science

S u m m a r y Plot the distribution of various oozes using information from Grade Level: sediment maps. 9-12

Object ives Lesson Time: 1 hr.

Descr~be the characterlstlcs of d~fferent types of seafloor sediments and oozes Mater ia ls Required: Predict dlstr lbut~on of calcareous and s~l~ceous oozes. g lobal map, Sed iment Compare and discuss locat~ons of sed~ments and oozes. D i s t r l b M i o n Pa t te rns

m a p

Vocabulary Terrlgenous, Blogenous, Hydrogenous, Cosmogenous, Calcareous Nat l . Science Standards ooze, Slllceous ooze, Foram~nlfera, Dlatoms, ad~olarla, Carbonate compensat~on depth -- Click h e r e f o r a l i s t o f

t h e a l igned Nat iona l G e n c e Educa t ion

I n t r o d u c t i o n Standards. --

1 Jr\

N A T I ~ ~ A ~ svlARI~~ Just as ocean beaches display a variety of sediment types, the ocean Related Resources EDUCATORS ASSOCIATION floor may be made or: sand, rock, remains of living organisms, or Geo logga l

other material. The grains and particles that make up the seafloor .,eanography,P,ankton, /?

I' I sediments are classified by their size and their point of origin. B e n t h o s

cx: .\. ! Sediments can come from land (terrigenous), from living organisms \ ,

,.>A ,&>~ (4 , (biogenous), from chemical reactions in the water column (hydrogenous), and even from outer space (cosmogenous).

Terriqenous sediments dominate the edqes of the ocean basins, close to land where they originated. As move deeper into the ocean basins, biogenous sediments begin to dominate. ~ iogenous sediments can consist of waste products or remains of organisms, including those of microscopic phytoplankton and zooplankton. When skeletal remains of microscopic organisms make up more than 30% of the sediment, it is called "ooze."

There are two types of oozes, calcareous ooze and siliceous ooze. Calcareous ooze, the most abundant of all biogenous sediments, comes from organisms whose shells (also called tests) are calcium-based, such as those of foramini fera, a type of zooplankton. Foraminifera are one of the most abundant types of zooplankton and are widely distributed throughout the surface of the world's oceans.

Siliceous oozes are made up of the remains of di~atornn, a microscopic phytoplankton, and radio lar ia , a microscopic zooplankton. Diatoms are one of the most important primary producers in the ocean. Because they are primary producers, diatoms are found in nutrient-rich areas of the ocean especially in areas of upwelling like the polar seas. As you move from continental shelf to open ocean areas, the number of diatoms present decreases. Radiolarians, the other source of siliceous ooze, feed on phytoplankton and thus are also more abundant in nutrient-rich water. However, radiolaria favor the equatorial upwelling zones as opposed to the polar upwelling zones.

Another factor that affects where biogenous sediments will occur is the depth of the ocean floor. Calcium carbonate dissolves readily under pressure and in cold water, therefore deeper ocean floors will have less calcareous ooze. At a depth of about 5 km, the rate of dissolution (how quickly calcium carbonate dissolves) is faster than the rate at which caicium shells are raining down from above. This depth is called the carbonate compensation depth or CCD.

Data Ac t i v i t y

Bridge Ocean Education Teacher Resource Center Page 2 of 2

DATA ACTIVITY

Using what you've learned about the distribution of diatoms, radiolaria and foraminifera and about the carbonate compensation depth, predict where you think you would find calcareous and siliceous oozes. Print a g l o b l - m a p , and mark your predictions on it.

Next, print the General Sediment Dist r ibut ion p a t t e r n s map. This map shows the general location of biogenous sediments. Compare your map to the sediment distribution map.

QUESTIONS

Were your predictions close to where calcareous and siliceous oozes actually occur? How does your map compare with the seqiment distribution map? Which type of ooze dominates the ocean sediments, calcareous or siliceous? Why? What parts of the oceans do not have calcareous ooze? What might be some reasons for this? (Hint: depth, distribution of organisms) Where are large deposits of siliceous diatom ooze? Are these deposits mostly near the edges of continents or in the middle of the ocean basins? Why? (Hint: areas of upwelling/high nutrient levels) Where do you see large deposits of siliceous radiolarian ooze? Why?

The Bridge is S ~ O ~ P S Q P ~ ~ by NOAA Sea Grant and t h e National Marine-Educata_rs Association

@ Virg in i i l Sca G r n ~ i l Mdt ine Advisory Program Virg in ia I n s t i t u t e o f Mar ine Science College o f Wi l l i am a n d Mary

Introduction to the Foraminifera Page 1 of 2

Introduction to the Foraminifera Foraminifera (forams for short) are single-celled protiss with shells. Their shells are also referred to as tests because in some forms the protoplasm covers the exterior of the shell. The shells are commonly divided into chambers which are added during growth, though the simplest forms are open tubes or hollow spheres. Depending on the species, the shell may be made of organic compounds, sand grains and other particles cemented together, or crystalline calcite.

A typical foram : In the picture about, the dark brown structure is the test, or shell, inside which the foram lives. Radiating from the opening are fine hairlike reticulopodia, which the foram uses to find and capture food.

Fully grown individuals range in size from about 100 micrometers to almost 20 centimeters long. A single individual may have one or many nuclei within its cell. The largest living species have a symbiotic relationship with algae, which they "farm" inside their shells. Other species eat foods ranging from dissolved organic molecules, bacteria, diatoms and other single celled phytoplankton, to small animals such as copepods. They move and catch their food with a network of thin extensions of the cytoplasm called reticulopodia, similar to the pseudopodia of an amoeba, although much more numerous and thinner.

Click on the buttons below to learn more about Foraminifera.

Introduction to the Foraminifera Page 2 of 2

Por more information about foraminifera : Try the Gulf of St.t.Law_r_ece Database, including images and information on Late Quaternary micro fossils.

Clickhere to see images of some type specimens from the UCMP inicrofossil collect~ns. - -

U C M P s h a r t c u t s :

tree time I home of life : periods : to(3ics glossary ; help

Introduction to the Bacillariophyta Page 1 of 2

Introduction to Bacillariophyta (The Diatoms)

Life inside a glass box. . .

The Bacillariophyta are the diatoms. With their exquisitely beautihl silica shells, or frustules such as that of Odontella shown above at right, diatoms are among the loveliest microfossils. They are also among the most important aquatic microorganisms today: they are extremely abundant both in the plankton and in sediments in marine and freshwater ecosystems, and because they are photosynthetic they are an important food source for marine organisms. Some may even be found in soils or on moist mosses.

Diatoms have an extensive fossil record going back to the Cretaceous; some rocks are forrned almost entirely of fossil diatoms, and are known as diatomite or diatomaceous earth. These deposits are mined conlmercially as abrasives and filtering aids. Analysis of fossil diatom assemblages may also provide important inforrnation on past environmental conditions.

Click on the buttons below to learn more about the Diatoms.

Introduction to the Bacillariophyta Page 2 of 2

You can search the UCMP ii~icropaleontology~ type collection for diatoms.

For more information on diatoms and how they are used in environmental reconstruction, check out the Paleolimnology and Diatom Home Pages maintained by P. Roger Sweets at Indiana University, or visit the Aka1 Microscopy and Image Digitization~Hoine Page at Bowling Green State University for many images of diatoms.

You might also want to visit the Diato.m_Collectioils_ of the California Academy of Sciences, including databases on diatom genera and literature.

A general article 011 diatoms (15 Sep 1997) is available from the Mining Company.

U C M P s h o r t c u t s :

tree home ' of life time topics ' gSossary j help : periods '

Image of living diatom courtesy Virtual Foliage at the University of Wisconsin. Electron micrograph of Odontella taken by Karen Wetmore at UCMP.

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Molecular Expressions Photo Gallery: Radiolarians

Radiolarians

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Mixed Radiolarians in Darkfield Illumination

Radiolarians

Radiolarians are single-celled protistan marine organisms that distinguish themselves with their unique and intricately detailed glass-like exoskeletons. During their life cycle, radiolarians absorb silicon compounds from their aquatic environment and secrete well-defined geometric networks that comprise a skeleton commonly known as a test. The radiolarian tests are produced in a wide variety of patterns, but most consist of an organized array of spines and holes (pores) that regulate a network of pseudopods useful in gathering food. When observed with an optical microscope, radiolarian tests are found to be low contrast light-scattering objects that are best viewed using Rheinberg illumination, darkfield illumination, phase contrast, or differential interference contrast (DIC) microscopy techniques. The diversity and beauty of radiolarian tests was first captured and revealed in 1862 by Ernst Haeckel's monograph, Die Radiolarien (Rhizopoda Radiaria), based on specimens gathered from the ocean by the Challenger research cruises of Alexander von Humboldt. The work features 35 exquisite copper plates illustrating hand-drawn radiolarians that still have not been surpassed in quality by modern optical and electron microscopy techniques.

Molecular Expressions Photo Gallery: Radiolarians Page 2 of 4

Radiolarian Exoskeleton in Differential Interference Contrast (DIC)

Diatoms, small zooplankton (such as copepods), and other protozoans serve as food sources for the predatory radiolarians. Prey is captured by members of the holoplanktonic radiolaria by engulfing it with their pseudopods, a feature shared by their relatives, the amoebas. The thin, linear ray-form plasmopodia are stretched through the pores of the tests to secure unsuspecting plankton and then retracted when the prey is secured. Digestion occurs in the central cavity. Although most are predatory, radiolaria exhibit wide behavioral variety and include some species that are filter feeders and others believed to be symbiotic with unicellular marine algae (zooxanthellae; more commonly known as dinoflagellates). The dinoflagellate symbionts are enclosed in a thin envelope of cytoplasm produced by the host radiolarian's rhizopodial system. Radiolaria provide ammonium and carbon dioxide for the dinoflagellates, who return the favor by providing the host with a jelly-like layer that serves both for protection and capturing prey. In relationships with marine algal symbionts, the host radiolarian is provided with much needed nourishment when food is scarce, allowing it to survive for several weeks without prey. This type of mutually beneficial relationship is generally found only within radiolarians that dwell in water that is shallow enough to receive significant amounts of light (water in the photopic zone).

Radiolarian in Phase Contrast lllumination

Although they occur widely distributed in the world's oceans, radiolarians are generally concentrated in low-latitude areas. The warm, rich waters of the equatorial zone are home to the most abundant radiolaria species. Radiolarians flourish throughout the water column, from the surface layers to hundreds of meters in depth. As with other marine planktonic organisms, the distribution and abundance of these microzooplankton are dependent on the quality of the water in their environment, including such variables as water temperature, salinity, silicon availability, and the occurrence of suitable nutrients. Radiolarians compete with diatoms for the limited dissolved silica (silicon dioxide) resources available in the ocean waters, which is required by both organisms for building exoskeletons.

Radiolarian in Rheinberg lllumination

Molecular Expressions Photo Gallery: Radiolarians Page 3 of 4

Cytoplasm from these microscopic marine creatures contains numerous vacuoles that fill with air to keep the animals afloat in the upper ocean waters. The nearly spherical symmetry of radiolarian silica tests, and the numerous extending spines and spicules, add to the buoyancy of these unicellular organisms, enabling them to drift along the ocean currents. The nucleus is surrounded by a central capsule of chitin and is the site of cell division during reproduction. The central capsule, separating the endoplasm from the ectoplasm, is a characteristic that distinguishes the radiolarians from other protists.

Radiolarians usually reproduce asexually, by division of the cell (including the exoskeleton), with the resulting daughter cells each regenerating a complete organism. In many cases radiolarians can also reproduce sexually. Ranging in size from 2 to 30 micrometers in diameter, the unicellular radiolaria feature a diversity in shape and geometric pattern that rivals the finest cut crystal glass creations. Although many species are solitary, there are colonial forms of these marine organisms (built from hundreds of radiolarian cells) with exoskeleton diameters ranging from several millimeters to a centimeter or larger for spherical colonies. When colonies form cylindrical or filiform aggregate geometries, the combined structures can range up to several meters in length, held together by simple siliceous networks.

Radiolarian in Hoffman Modulation Contrast

The radiolarian exoskeleton, featured in the photomicrographs presented in this section, is encased in the cellular cytoplasm with the bulk of the test being set in the ectoplasm. This anatomical feature ensures that the amorphous silica skeletal structure is never in direct contact with seawater, reducing the risk of dissolution in a hostile aqueous saline environment. When radiolarians die, their tests usually sink and accumulate on the ocean floor in biogenic sediments. Contributing to the pelagic oozes that date back millions of years, the ancient radiolaria skeletons are often useful in geological dating experiments, climatological studies, and oil exploration. The process of biogenic sedimentation, which began with primitive members of the radiolaria during the Early Cambrian period, continues on today. Unlike the diatoms, where perhaps 90 percent of the documented species are still living, approximately 90 percent of the several thousand described and indexed radiolaria now exist only in fossil form.

Holtre fduklcroecopy Btroto Silicon Page Primer Gallery Zoo lr'laQe Use ~ e a r c h

Photomicrography and text by Laurence D. Zuckerman, Thomas J. Feller~, Omar Alvarado, and Michael W. Davidson.

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Molecular Expressions Photo Gallery: Radiolarians

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Siliceous Page 1 of 1

Themes > Science > Earth Sciences > Oceanonraphv > Ocean Sediments > Pelaaic sediments > Siliceous-Pelagic sediments

Terrigenous deposits: Biogenous deposits: H Hycfogenous deposls 0 Continental margins Calcareous oozes ako p r e s e ~

Glacial deposits E Siliceous radiolarian oozes Clays Siliceous diatom oozes

1 Siliceous pelagic

1 sediments

Consist of clay-silt- s an d sized particles deli>-ed from pl1yto plaldcto 11 or

zooplallkton in the photic zone. Siliceons sed.ilnents occur mostly

below the CCD or under coastal or oceanic nprvelling systems

Siliceous-Pelaglc sediments are rich in the remains of diatoms, silicoflagelattes and radiolaria. They occur most commonly below the CCD and in areas around the Antarctic and tropical and coastal upwelling zones where extremely high production of siliceous organisms occurs resulting in great export production of siliceous microfossils. Note that there is no such area in the GIN Seas or the North Atlantic because the diluting effects of large amounts of terrigenous and carbonate material in sedimentary water depth that are above the CCD here.

Information provided by: http://hjs.geol.uib.no