Living Planktonic Foraminifera from the Equatorial and Southeast Pacific
1. A study was made of 81 plankton samples, mostly from the equatorial and southeast Pacific Ocean. The distribution patterns of 16 of the more common planktonic species of Foraminifera are as follows : 1) Widespread-Globigerinella aequilateralis, Globigerinoides ruber, Hastigerina pelagica, Orbcdin...
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| Format: | Report |
| Language: | English |
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Tohoku University
1960
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| Online Access: | http://hdl.handle.net/10097/28883 https://tohoku.repo.nii.ac.jp/?action=repository_uri&item_id=10738 https://tohoku.repo.nii.ac.jp/?action=repository_action_common_download&item_id=10738&item_no=1&attribute_id=18&file_no=1 |
| Summary: | 1. A study was made of 81 plankton samples, mostly from the equatorial and southeast Pacific Ocean. The distribution patterns of 16 of the more common planktonic species of Foraminifera are as follows : 1) Widespread-Globigerinella aequilateralis, Globigerinoides ruber, Hastigerina pelagica, Orbcdina universa 2) Equatorial and southeast-central-Globigerina eggeri, Globigerinoides conglobatus, G. sacculifer 3) Equatorial-Globigerina conglomerata, G. hexagona, Globorotalia menardii (few exceptions), Pulleniatina obliquiloculata (one exception) 4) Southeast central and subantarctic-Globigerina bulloides, G. inflata, Globorotalia punctulata, G. truncatulinoides 5) Subantarctic-Globorotalia scitula. 2. Temperature may be more critical than salinity in controlling these distributions. No conclusions about the physical limits for survival of the planktonic species can be formed until it is known exactly at what water levels they live. 3. Total populations were largest in the equatorial region, in a small area close to the coast of South America, and at a few stations in the northern part of the subantarctic region. These are the regions richest in nutrients. 4. The largest populations were found in the upper 200 m. In addition, the populations from daytime oblique tows from various depths exceeded by a factor of ten the number found in corresponding night tows at the same station. The possible dependence of the planktonic Foraminifera on symbiotic algae is suggested as the reason for the apparent preference for the euphotic zone. Nothing further can be said until more is known about the habits of the planktonic Foraminifera. |
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