Sound propagation through the near‐surface ocean bubble layer

1996 ◽  
Vol 100 (4) ◽  
pp. 2840-2840 ◽  
Author(s):  
Holly Burch ◽  
Michael Buckingham
Keyword(s):  
Sound Propagation ◽  
Near Surface ◽  
Surface Ocean ◽  
Bubble Layer

scholarly journals Stable near-surface ocean salinity stratifications due to evaporation observed during STRASSE

2014 ◽  
Vol 119 (5) ◽  
pp. 3219-3233 ◽  
Author(s):  
William E. Asher ◽  
Andrew T. Jessup ◽  
Dan Clark
Keyword(s):  
Near Surface ◽  
Surface Ocean ◽  
Ocean Salinity

What is gradualism? Cryptic speciation in globorotaliid foraminifera

Paleobiology ◽  
1996 ◽  
Vol 22 (3) ◽  
pp. 386-405 ◽  
Author(s):  
Richard D. Norris ◽  
Richard M. Corfield ◽  
Julie Cartlidge
Keyword(s):  
Reproductive Isolation ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Reproductive Ecology ◽  
Shell Growth ◽  
Shell Shape ◽  
Planktic Foraminifera ◽  
Near Surface ◽  
Surface Ocean ◽  
Speciation Event

Analysis of the evolution of the Globorotalia (Fohsella) lineage of planktic foraminifera suggests that reproductive ecology and shell shape have evolved independently in this group. The silhouette of fohsellid shells displays a nearly unbroken anagenetic trend, yet isotopic data show that the fohsellids changed their depth of reproduction during the anagenetic evolution of their skeletons. Remarkably, there are no correlations between anagenesis in skeletal shape and the establishment of reproductive isolation. Apparently, anagenesis masks at least one speciation event that is apparent only in the isotopic evidence for a change in reproductive ecology. Although anagenetic trends have been widely cited as evidence for gradual speciation in planktic foraminifera and other microfossil groups, our data suggest that they should not always be considered to record either the tempo or mode of speciation.Speciation was apparently uncoupled from morphological evolution in fohsellids because these evolutionary phenomena occurred in different phases of ontogeny. Gradual morphological changes were associated with the main phase of shell growth of both the ancestor and descendant species in the near-surface ocean. Reproductive isolation occurred when ancestral and descendant populations became established at different depths near the end of the life cycle. Morphological evolution may also be uncoupled from reproductive isolation in other organisms that experience very different selection pressures over the duration of their ontogenies, such as parasites with many hosts, species with multiple phases of metamorphosis, and organisms that broadcast their gametes.

Temporal coherence of acoustic signals propagating through the near surface bubble layer

2002 ◽  
Vol 112 (5) ◽  
pp. 2424-2424
Author(s):  
R. Lee Culver ◽  
David Bradley ◽  
Jon Reeves
Keyword(s):  
Acoustic Signals ◽  
Temporal Coherence ◽  
Near Surface ◽  
Bubble Layer ◽  
Surface Bubble

Sound Propagation through an Underwater Bubble Layer with Transition Sublayers

1996 ◽  
Author(s):  
S. W. Yoon ◽  
B. K. Choi ◽  
A. M. Sutin ◽  
I. N. Didenkulov
Keyword(s):  
Sound Propagation ◽  
Bubble Layer

Distribution of zooplankton inferred from hydroacoustic backscatter data in coastal waters off Ningaloo Reef, Western Australia

2002 ◽  
Vol 53 (6) ◽  
pp. 1005 ◽  
Author(s):  
Steven G. Wilson ◽  
Timothy Pauly ◽  
Mark G. Meekan
Keyword(s):  
Western Australia ◽  
Coastal Waters ◽  
Near Surface ◽  
Rhincodon Typus ◽  
Ningaloo Reef ◽  
The North ◽  
Whale Sharks ◽  
Bubble Layer ◽  
Surface Bubble

Hydroacoustic surveys were used to examine zooplankton distributions in coastal waters off Ningaloo Reef, Western Australia. Surveys were timed to coincide with the seasonal aggregation of whale sharks, Rhincodon typus, and other large zooplanktivores in these waters. The surveys examined scattering features of lagoon/shelf fronts, a series of cross-shelf transects and waters surrounding whale sharks swimming at the surface. These suggested that lagoon waters flow intrusively into shelf waters at reef passages in a layered exchange. Cross-shelf transects identified three vertical scattering layers: a surface bubble layer; a near-surface minimum layer; and a bottom maximum layer. Regions of intense mixing of lagoon and shelf waters were detected seaward and to the north of reef passages. Integrated acoustic mean volume backscatter of the bottom maximum layer increased with depth and distance offshore. Large subsurface aggregations of unidentified fauna were detected beneath whale sharks in the same area that manta rays and surface schools of euphausiids were also observed.

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