Vertical flux, ecology and dissolution of radiolaria in tropical oceans : implications for the silica cycle
type: CreativeWork
description: Radiolarians which settle through the oceanic water column were recovered from three stations (western Tropical Atlantic-Station E, central Tropical Pacific-Pi and Panama Basin-PB) using PARLUX sediment traps in moored arrays at several depths. The taxonomic diversities of the radiolarian assemblages in the sediment traps were very high. A total of 420 taxa, including 23 newly identified taxa, were found at the three stations; of these, 208 taxa were found at station E. The polycystine radiolarians generally reach the sea floor with little change in abundance or species composition, although slight skeletal dissolution occurs throughout their descent. The phaeodarian radiolarians, on the other hand, are largely dissolved within the water column; only a few species reach the sea-floor and these dissolve rapidly at the sediment-water interface. Most radiolarian skeletons sink as individuals through deep water columns without being incorporated into large biogenic aggregates. Because significant numbers of nassellarian and phaeodarian species are deep-water dwelling forms the diversity index of radiolarians increases with increasing depth in the mesopelagic zone. The vertical flux of the total radiolarians arriving at the trap depths (in x 103 individuals/m2/day) ranged from 16-24 (E), 0.6-17 (Pl), and 29-53 (PB). Of these on the average 25% and 69% of the total radiolarian flux is transported by Spumellaria and Nassellaria, respectively, while 5% is carried by Phaeodaria. The measured Si02 content of the skeletons averaged 91, 98 and 71% of measured weight for Spumellaria, Nassellaria and Phaeodaria, respectively. The supply of radiolarian silica (mg Si02/m2/day) to each trap depth ranged from 2.5-4.0 (E), 0.9-3.2 (Pl), and 5.7-10.4 (PB). The Radiolaria appear to be a significantly large portion of the Si02 flux in >63 pm size fraction and thus play an important role in the silica cycle. When the radiolarian fluxes at the three Stations are compared with Holocene radi…
abstract: Radiolarians which settle through the oceanic water column were recovered from three stations (western Tropical Atlantic-Station E, central Tropical Pacific-Pi and Panama Basin-PB) using PARLUX sediment traps in moored arrays at several depths. The taxonomic diversities of the radiolarian assemblages in the sediment traps were very high. A total of 420 taxa, including 23 newly identified taxa, were found at the three stations; of these, 208 taxa were found at station E. The polycystine radiolarians generally reach the sea floor with little change in abundance or species composition, although slight skeletal dissolution occurs throughout their descent. The phaeodarian radiolarians, on the other hand, are largely dissolved within the water column; only a few species reach the sea-floor and these dissolve rapidly at the sediment-water interface. Most radiolarian skeletons sink as individuals through deep water columns without being incorporated into large biogenic aggregates. Because significant numbers of nassellarian and phaeodarian species are deep-water dwelling forms the diversity index of radiolarians increases with increasing depth in the mesopelagic zone. The vertical flux of the total radiolarians arriving at the trap depths (in x 103 individuals/m2/day) ranged from 16-24 (E), 0.6-17 (Pl), and 29-53 (PB). Of these on the average 25% and 69% of the total radiolarian flux is transported by Spumellaria and Nassellaria, respectively, while 5% is carried by Phaeodaria. The measured Si02 content of the skeletons averaged 91, 98 and 71% of measured weight for Spumellaria, Nassellaria and Phaeodaria, respectively. The supply of radiolarian silica (mg Si02/m2/day) to each trap depth ranged from 2.5-4.0 (E), 0.9-3.2 (Pl), and 5.7-10.4 (PB). The Radiolaria appear to be a significantly large portion of the Si02 flux in >63 pm size fraction and thus play an important role in the silica cycle. When the radiolarian fluxes at the three Stations are compared with Holocene radi…
author: Takahashi, Kozo
language: en_US
keywords: Radiolaria, Fossil, Marine sediments, Atlantis II (Ship : 1963-) Cruise AII108-2
date published: 1981-11
date modified: 2026-07-27T22:05:19Z
provider: Woods Hole Oceanographic Institute
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

PropertyValue
property ID: Handle
value: https://hdl.handle.net/1912/2420

PropertyValue
property ID: DOI
value: 10.1575/1912/2420