Hitchcock,G.L.,Lane,P.,Smith,S.,Luo,J.G.,Ortner,P.B.
Zooplankton spatial distributions in coastal waters of the northern Arabian Sea, August 1995 Journal Article
In: Deep-Sea Research Part II, vol. 49, no. 387, pp. 2403-2423, 2002.
Abstract | BibTeX | Tags: acoustic, Arabian Sea, displacement, Distribution, migration, Oman, surface temperature, temperature, trend, Upwelling, zooplankton
@article{,
title = {Zooplankton spatial distributions in coastal waters of the northern Arabian Sea, August 1995},
author = {Hitchcock,G.L.,Lane,P.,Smith,S.,Luo,J.G.,Ortner,P.B.},
year = {2002},
date = {2002-01-01},
journal = {Deep-Sea Research Part II},
volume = {49},
number = {387},
pages = {2403-2423},
abstract = {The spatial distribution of zooplankton biomass was surveyed in coastal waters of the northern Arabian Sea during the 1995 Southwest Monsoon (August) on cruise MB 95-06 of the NOAA Ship Malcolm Baldrige. Vertical patterns of displacement volumes from a limited set of paired day-night MOCNESS tows suggest there was little diel vertical migration in the coastal waters off the southern Arabian Peninsula. Zooplankton biomass varied from 5.2 to 15.1 9 dw m(-2) (178-517mM Cm-2) in the upper 200-300m of Omani coastal waters. Distributions of acoustic backscatter were mapped in eight daytime acoustic Doppler current profiler transects in coastal waters off Oman and Somalia. Several transects contained maxima in acoustic backscatter that coincided with cool, fresh surface features that were several tens of kilometers wide. Although there was considerable scatter in the relationship between acoustically determined biomass (ADB) of zooplankton and surface temperature, there was a trend of increased biomass in the cool surface temperatures of the Omani upwelling zone. Acoustic transects crossed two filaments that extended seaward from upwelling centers off Oman and Somalia. Estimated zooplankton ADB exported from the upwelling zones in the surface features was on the order of 300 kg dw s( -1 ). The physical and biological characteristics of filaments maintain zooplankton associated with upwelling areas, such as Calanoides carinatus, as they are advected offshore from coastal upwelling zones. (C) 2002 Published by Elsevier Science Ltd.},
keywords = {acoustic, Arabian Sea, displacement, Distribution, migration, Oman, surface temperature, temperature, trend, Upwelling, zooplankton},
pubstate = {published},
tppubtype = {article}
}
The spatial distribution of zooplankton biomass was surveyed in coastal waters of the northern Arabian Sea during the 1995 Southwest Monsoon (August) on cruise MB 95-06 of the NOAA Ship Malcolm Baldrige. Vertical patterns of displacement volumes from a limited set of paired day-night MOCNESS tows suggest there was little diel vertical migration in the coastal waters off the southern Arabian Peninsula. Zooplankton biomass varied from 5.2 to 15.1 9 dw m(-2) (178-517mM Cm-2) in the upper 200-300m of Omani coastal waters. Distributions of acoustic backscatter were mapped in eight daytime acoustic Doppler current profiler transects in coastal waters off Oman and Somalia. Several transects contained maxima in acoustic backscatter that coincided with cool, fresh surface features that were several tens of kilometers wide. Although there was considerable scatter in the relationship between acoustically determined biomass (ADB) of zooplankton and surface temperature, there was a trend of increased biomass in the cool surface temperatures of the Omani upwelling zone. Acoustic transects crossed two filaments that extended seaward from upwelling centers off Oman and Somalia. Estimated zooplankton ADB exported from the upwelling zones in the surface features was on the order of 300 kg dw s( -1 ). The physical and biological characteristics of filaments maintain zooplankton associated with upwelling areas, such as Calanoides carinatus, as they are advected offshore from coastal upwelling zones. (C) 2002 Published by Elsevier Science Ltd.
Luo,J.,Ortner,P.B.,Forcucci,D.,Cummings,S.R.
Diel vertical migration of zooplankton and mesopelagic fish in the Arabian Sea Journal Article
In: Deep-Sea Research Part II, vol. 47 , no. 145, pp. 1451-1473, 2000.
Abstract | BibTeX | Tags: acoustic, Arabian Sea, depth, diel, displacement, fish, migration, oxygen minimum, sonar, temperature, zooplankton
@article{,
title = {Diel vertical migration of zooplankton and mesopelagic fish in the Arabian Sea},
author = {Luo,J.,Ortner,P.B.,Forcucci,D.,Cummings,S.R.},
year = {2000},
date = {2000-01-01},
journal = {Deep-Sea Research Part II},
volume = {47 },
number = {145},
pages = {1451-1473},
abstract = {Acoustic (153 kHz ADCP and 12 kHz hull-mounted transducers) data and MOCNESS (MOC01 and MOC10) net tow samples collected in the Arabian Sea during the Spring Intermonsoon (April/May) and Southwest Monsoon (August) in 1995 documented substantial diel migrations of fish and zooplankton despite the year-round presence of an oxygen minimum ((0.2 ml l-1 at 125-150 m). Fish and zooplankton layers were distinguished by comparing 12 kHz sonar and 153 kHz ADCP backscatter data, which indicated that the strongly migrating layers were predominantly composed of fishes. Fish vertical migration speeds were independently estimated from the slopes of the volume scattering layers and from the vertical velocity components of the ADCP, yielding average speeds of 4 and 3 cm s-1 and maximum speeds of 13 and 10 cm s-1, respectively. A few migrating zooplankton layers were identified with an average speed of about 2 cm s-1 and maximum speeds as high as 8 cm s-1. Migration depths for both zooplankton and fish differed somewhat amongst stations and appeared to be related to local hydrographic conditions (principally the vertical gradients in DO and water temperature). Zooplankton displacement volumes at individual sites suggested that zooplankton biomass during the Southwest Monsoon could be as much as fivefold greater than during the Spring Intermonsoon. This observation was confirmed for the region in general by first deriving a relationship between ADCP backscatter intensity and daytime zooplankton biomass and then comparing the latter between cruises using daytime ADCP data taken along a 1500 km transect that extended from the coast of Somalia to the center of the northern basin.},
keywords = {acoustic, Arabian Sea, depth, diel, displacement, fish, migration, oxygen minimum, sonar, temperature, zooplankton},
pubstate = {published},
tppubtype = {article}
}
Acoustic (153 kHz ADCP and 12 kHz hull-mounted transducers) data and MOCNESS (MOC01 and MOC10) net tow samples collected in the Arabian Sea during the Spring Intermonsoon (April/May) and Southwest Monsoon (August) in 1995 documented substantial diel migrations of fish and zooplankton despite the year-round presence of an oxygen minimum ((0.2 ml l-1 at 125-150 m). Fish and zooplankton layers were distinguished by comparing 12 kHz sonar and 153 kHz ADCP backscatter data, which indicated that the strongly migrating layers were predominantly composed of fishes. Fish vertical migration speeds were independently estimated from the slopes of the volume scattering layers and from the vertical velocity components of the ADCP, yielding average speeds of 4 and 3 cm s-1 and maximum speeds of 13 and 10 cm s-1, respectively. A few migrating zooplankton layers were identified with an average speed of about 2 cm s-1 and maximum speeds as high as 8 cm s-1. Migration depths for both zooplankton and fish differed somewhat amongst stations and appeared to be related to local hydrographic conditions (principally the vertical gradients in DO and water temperature). Zooplankton displacement volumes at individual sites suggested that zooplankton biomass during the Southwest Monsoon could be as much as fivefold greater than during the Spring Intermonsoon. This observation was confirmed for the region in general by first deriving a relationship between ADCP backscatter intensity and daytime zooplankton biomass and then comparing the latter between cruises using daytime ADCP data taken along a 1500 km transect that extended from the coast of Somalia to the center of the northern basin.