Aid to Science 



Geologists have spent much time attempting 

 to learn the age of the world and to date events 

 that have led to the development of the present 

 land naasses. Some recent advances in this 

 knowledge depended on determination of the 

 age of fossil shells of planktonic organisms 

 by the radiocarbon technique. This method 

 measures the amount of radiocarbon remain- 

 ing in a sample of the shells. Studies of fossil 

 diatoms in deposits such as the one at Lompoc, 

 Calif., have yielded much valuable information. 



A complete time scale, determined by radio- 

 carbon study of cores bored from deep-sea 

 sediments, dates the beginning of the ice age 

 at about 1-1/2 million years ago. Well-defined 

 changes in the abundance of the shells of cer- 

 tain species of Foraminifera in cores fronn 

 the equatorial Atlantic and around the world 

 give a legible record of major climatic events 

 during the ice age. 



Intensive oceanographic studies now being 

 organized cooperatively by many nations and 

 the international expeditions of recent years^ 

 are expected to add much new information about 

 the sea and its inhabitants. No doubt, new 

 uses for plankton will be developed as a 

 result of this greater knowledge. 



LUMINESCENCE 



A boat ride after dark at sea is pure delight 

 when the bow wave and the wake behind the boat 

 sparkle with tiny points of light known as 

 luminescence. If the boat happens to be small, 

 reach into the water; your hand will come out 

 with some of the points of light clinging to it. 

 Rub your hands gently together and feel small 

 prickles. Put the bits of light into a drop of 

 water under a nnicroscope, and the wonderful 

 world of dinoflagellates comes to life for you. 

 Think then, as many others have done, how 

 light is produced by these small creatures. 

 The chemical nature of their photogenic cells 

 was still unknown as recently as 1962. The 

 dinoflagellates, minute animals or plants (ex- 

 perts disagree), are characterized by the 

 presence of two flagella in grooves (see 

 Peridinium and Ceratium , fig. 1). Usually the 

 body is covered by a cellulose shell. Many of 

 these strange little creatures possess photo- 

 synthetic pigment but cannot exist without 

 organic food; they are able to survive indefi- 

 nitely without light if all required food ele- 

 ments are present. 



The most common luminescent flagellate is 

 Noctiluca scintillans , which is 12 percent dry 

 nnatter in the form of granules that are be- 

 lieved to be the source of luminescence upon 



Examples are the International Indian Ocean Expedition 

 and the International Cooperative Investigations of the 

 Tropical Atlantic. 



mechanical or chemical stimulation. A number 

 of other dinoflagellates- - Gymnodinium , Cera- 

 tium, and Gonyaulax - -also emit light in re- 

 sponse to similar stimuli. These luminescent 

 flagellates are widely distributed in salt 

 water. 



HARMFUL EFFECTS OF PLANKTON 



Waters that receive domestic and industrial 

 wastes containing large amounts of nitrogen 

 and phosphorus compounds often nourish heavy 

 growths of algae. The algae may interfere at 

 such times in manufacturing processes and 

 in the operation of city water plants by clog- 

 ging filters, and also may decrease recrea- 

 tional and esthetic values of shore property 

 by producing unsightly accumulations in the 

 water at bathing beaches and boating areas. 

 Although algae use carbon dioxide and produce 

 oxygen in photosynthesis during their short 

 life span, the decay of large concentrations of 

 their dead cells frequently depletes the oxygen 

 in the water. Massive fish-kills may result. 

 The decay of algal masses occasionally gives 

 disagreeable tastes and odors to city water 

 supplies and sometimes releases sufficient 

 hydrogen sulfide into the air to discolor paint 

 on boats and on nearby houses. 



Some species of algae produce toxins in- 

 jurious or fatal to animals. One of these, 

 Gonyaulax catenalla, when eaten by sea mus- 

 sels and clams, produces an alkaloid substance 

 that is harmless to the bivalves but is poison- 

 ous to the people who eat them. Many cases 

 of illness and some deaths have been reported 

 from this so-called mussel-poisoning. 



REFERENCES 



ABRAMOVA, V. D, 



1956. Plankton as an indicator of waters of 

 different origin in the North Atlantic 

 seas, Tr. Polyarn. Nauch.-issled. Inst. 

 Morsk. Rybn. Khoz. i Okeanogr., No. 

 9:69-92. In Russian. Transl. avail, in 

 U.S. Fish. Wildl. Serv., Spec. Sci. Rep. 

 Fish. 327: 77-103. 



ALFIMOV, N. N., and O. G. MIRONOV. 



1958. The effect of diatomaceous plankton 

 of rivers on certain chemical indices 

 of water contamination. Bot. Zhur. 43- 

 (12): 1763-1765. 



AL'TOVSKII, M. E., Z. I. KUZNETSOVA, and 

 V. M, SHVETS. 

 1961 . Origin of oil and oil deposits. Russian 

 text published by Gostoptekhizdat, the 

 State Scientific and Technical Publish- 

 ing House of the Petroleum and Mineral- 

 Fuel Industry, Moscow, 1958, vii + 107 

 p. Transl. avail. Consultants Bureau 

 Enterprises, Inc., 227 W. 17th St., New 

 York, N.Y. 



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