New paedomorphic brachiopods from the abyssal zone of the north-eastern Pacific Ocean

Zootaxa ◽  
2013 ◽  
Vol 3613 (3) ◽  
pp. 281-288 ◽  
Author(s):  
MARIA ALEKSANDRA BITNER ◽  
VJACHESLAV P. MELNIK ◽  
OLGA N. ZEZINA
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
New Genera ◽  
Eastern Pacific Ocean ◽  
The North ◽  
The Pacific ◽  
North Eastern ◽  
The Pacific Ocean ◽  
Abyssal Zone ◽  
Sexually Mature

New Recent very small but sexually mature brachiopods have been found at abyssal depths (4580–4850 m) in the Clarion- Clipperton Zone of the Pacific Ocean. They are characterized by simple (under-developed, juvenile) morphological fea-tures, which are interpreted here as paedomorphic, indicating the importance of heterochrony in the evolution of deep-sea brachiopods. We have described these brachiopods as representing two new genera and species, i.e. Oceanithyris juveni-formis Bitner & Zezina (Family ?Dyscoliidae) and Simpliciforma profunda Bitner & Zezina (Superfamily Gwynioidea).

scholarly journals Biogeochemistry of the North Atlantic during oceanic anoxic event 2: role of changes in ocean circulation and phosphorus input

2014 ◽  
Vol 11 (4) ◽  
pp. 977-993 ◽  
Author(s):  
I. Ruvalcaba Baroni ◽  
R. P. M. Topper ◽  
N. A. G. M. van Helmond ◽  
H. Brinkhuis ◽  
C. P. Slomp
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Primary Productivity ◽  
Low Oxygen ◽  
Deep Basin ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Atlantic

Abstract. The geological record provides evidence for the periodic occurrence of water column anoxia and formation of organic-rich deposits in the North Atlantic Ocean during the mid-Cretaceous (hereafter called the proto-North Atlantic). Both changes in primary productivity and oceanic circulation likely played a role in the development of the low-oxygen conditions. Several studies suggest that an increased input of phosphorus from land initiated oceanic anoxic events (OAEs). Other proposed mechanisms invoke a vigorous upwelling system and an ocean circulation pattern that acted as a trap for nutrients from the Pacific Ocean. Here, we use a detailed biogeochemical box model for the proto-North Atlantic to analyse under what conditions anoxia could have developed during OAE2 (94 Ma). The model explicitly describes the coupled water, carbon, oxygen and phosphorus cycles for the deep basin and continental shelves. In our simulations, we assume the vigorous water circulation from a recent regional ocean model study. Our model results for pre-OAE2 and OAE2 conditions are compared to sediment records of organic carbon and proxies for photic zone euxinia and bottom water redox conditions (e.g. isorenieratane, carbon/phosphorus ratios). Our results show that a strongly elevated input of phosphorus from rivers and the Pacific Ocean relative to pre-OAE2 conditions is a requirement for the widespread development of low oxygen in the proto-North Atlantic during OAE2. Moreover, anoxia in the proto-North Atlantic is shown to be greatly influenced by the oxygen concentration of Pacific bottom waters. In our model, primary productivity increased significantly upon the transition from pre-OAE2 to OAE2 conditions. Our model captures the regional trends in anoxia as deduced from observations, with euxinia spreading to the northern and eastern shelves but with the most intense euxinia occurring along the southern coast. However, anoxia in the central deep basin is difficult to achieve in the model. This suggests that the ocean circulation used in the model may be too vigorous and/or that anoxia in the proto-North Atlantic was less widespread than previously thought.

IX. Contributions to terrestrial magnetism.—No. IV

1843 ◽  
Vol 133 ◽  
pp. 113-143 ◽  
Keyword(s):  
Pacific Ocean ◽  
West Coast ◽  
China Seas ◽  
North West ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Times ◽  
The China Seas

In the present number of these Contributions, I resume the consideration of Captain Sir Edward Belcher’s magnetic observations, of which the first portion, viz. that of the stations on the north-west coast of America and adjacent islands, was discussed in No. II. The return to England of Her Majesty’s ship Sulphur by the route of the Pacific Ocean, and her detention for some months in the China Seas, have enabled Sir Edward Belcher to add magnetic determinations at thirty-two stations to those at the twenty-nine stations previously recorded. In the notice of the earlier observations, a provisional coefficient was employed in the formula for the temperature corrections of the results with the intensity needles, as no experiments had then been made for the determination of their individual co­efficients. As soon therefore as Sir Edward Belcher had completed the observation of the times of vibration of those needles at Woolwich, as the concluding station of the series made with them, Lieut. Riddell, R. A. undertook the determination of their several coefficients, which was performed in the manner and with the results described in the subjoined memorandum.

scholarly journals A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas

2016 ◽  
Vol 283 (1844) ◽  
pp. 20162337 ◽  
Author(s):  
Steffen Kiel
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Subduction Zones ◽  
Continental Margins ◽  
Stepping Stones ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Active Continental Margins ◽  
Ocean Ridge

Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.

scholarly journals Association of deep-sea incirrate octopods with manganese crusts and nodule fields in the Pacific Ocean

2016 ◽  
Vol 26 (24) ◽  
pp. R1268-R1269 ◽  
Author(s):  
Autun Purser ◽  
Yann Marcon ◽  
Henk-Jan T. Hoving ◽  
Michael Vecchione ◽  
Uwe Piatkowski ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
The Pacific ◽  
The Pacific Ocean
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