File:Bulletin (1971-) (20414356552).jpg

Title: Bulletin
Identifier: bulletin7073sout (find matches)
Year: 1971- (1970s)
Authors: Southern California Academy of Sciences
Subjects: Science; Natural history; Natural history
Publisher: Los Angeles, Calif. : The Academy
Contributing Library: New York Botanical Garden, LuEsther T. Mertz Library
Digitizing Sponsor: The LuEsther T Mertz Library, the New York Botanical Garden

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
28 BULLETIN SOUTHERN CALIEORNIA ACADEMY OF SCIENCES VOLUME 70 Table II. Rate (r'< ) of incidence of suctorians on the species of Lucicutia L. polaris L. pseudopolaris L. anomala Female 65 1 1 12 Male 77 29 12 Stage V 42 32 — They inhabit deep water, the Arctic Bottom Water, and show different but overlapping ranges of verti- cal distribution. L. pseudopolaris is abundant at a depth of about 1500 m and diminishes gradually in abundance from there to disappear above 1000 m and below 3000 m. L. polaris seems to inhabit depths between 1500 m and less than 3000 m. It was found in greatest numbers at a depth of about 2000 m. L. anomala lives in deeper water from about 2000 m to more than 3000 m. It is more abundant at depths exceeding 3000 m (Fig. 5). The Arctic bottom water, as defined by Coach- man (1963), is a homogeneous water mass below about 900 m depth, with average temperatures from 0.0 to -1.0°C and salinities from 34.90 °/°° to 34.99 °/°°. Other studies and oceanographic data have demonstrated that chemical parameters such as oxygen, phosphate and silicate have a remarkable uniformity in this water mass (Kusunoki et al., 1966; Muguruma, 1961; English, 1961). Among the physical parameters, light is not likely to be a controlling factor for the vertical distribution of Arctic species at the depths in question. Conse- quently, it seems that among the measured physico- chemical parameters the only one which might have a major effect on the vertical distribution of these species could be pressure. Among the biological factors which might restrict these species to different ranges of depths we must consider food availability and competition for food. English (1963) briefly discussed the possible sources of food for zooplankton in the Arctic Ocean, and suggested that the production of particulate food by secondary producers of the nannoplankton could play a more important role in the Arctic Ocean than in other areas. In regard to the Arctic bottom water, it is likely that food for filter-feeders can be provided by the local secondary producers of the nannoplankton. and by sinking of dead organisms, detritus, and aggregates of organic matter from the upper layers. Several studies on the formation, distribution, and role of detritus and aggregates of organic matter in the sea (Parsons and Strickland, 1962; Riley, 1963; Menzel and Goering, 1966; J0rgensen, 1966; Johannes, 1967) concluded that they can be considered as a very important potential source of food for filter feeders. A close relationship between the feeding habits of calanoid copepods and the structure of their oral appendages was experimentally shown by Anraku and Omori (1963). The comparison between the oral appendages of the Arctic species of Lucicutia, and those studied by Anraku and Omori, indicated that Lucicutia has characteristics of herbivorous and omnivorous forms. The mesh formed by the setules of the maxillae, the filtering appendages, is of about 5 to 10,u in L. pseudopolaris and L. polaris and slightly smaller than 5/j. in L. anomala. This fine mesh and the structure of the oral appendages
Text Appearing After Image:
Figure 4— Lucicutia polaris Brodsky. Stage IV cope podite: a, dorsal view; b, lateral view; c, first leg; d, fifth leg. Lucicutia pseudopolaris Heptner. Stage IV cope- podite: e, dorsal view; f, lateral view; g, first leg; h, fifth leg. Stage V copepodite, female: i, lateral view; j, first leg; k, fifth leg. Stage V copepodite, male: 1, lateral view; m, fifth leg. Lucicutia anomala Brodsky. Male: n, dorsal view; o, lateral view; p, mandibular gnatho- base; q, first leg; r, fifth leg; s, inner margin of second basal segment of right fifth leg in three different specimens.

Note About Images