Seasonal and annual variability in daily vertical migration observed from acoustic Doppler current profiler derived backscatter at the Mid-Atlantic Bight shelf break

2020 ◽  
Vol 148 (4) ◽  
pp. 2445-2445
Author(s):  
Jacob S. Partida ◽  
Weifeng G. Zhang ◽  
Andone C. Lavery ◽  
J Michael Jech
Keyword(s):  
Vertical Migration ◽  
Acoustic Doppler Current Profiler ◽  
Shelf Break ◽  
Annual Variability ◽  
Current Profiler

Seasonal changes in the diel vertical migration of Chaoborus punctipennis larval instars

2014 ◽  
Vol 71 (5) ◽  
pp. 665-674 ◽  
Author(s):  
Lauren Emily Barth ◽  
W. Gary Sprules ◽  
Mathew Wells ◽  
Melissa Coman
Keyword(s):  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Acoustic Doppler Current Profiler ◽  
Acoustic Backscatter ◽  
Migration Behavior ◽  
Larval Instars ◽  
Reverse Migration ◽  
Coregonus Artedi ◽  
Chaoborus Punctipennis ◽  
Current Profiler

We describe a novel seasonal shift in the vertical migration behavior of Chaoborus punctipennis second-instar larvae in Lake Opeongo, Ontario. An upward-looking 600 kHz acoustic Doppler current profiler (ADCP) moored at a fixed 22 m station in the lake recorded acoustic backscatter continuously during the study period. Zooplankton samples collected indicated that the abundance of C. punctipennis larval instars accounted for the greatest proportion of variance in the linear backscatter from the ADCP. The large fourth-instar larvae underwent normal diel vertical migration throughout the study. Smaller second-instar larvae underwent reverse migration during late June but switched to normal migration by late July. The acoustic record indicates that the switch occurred over a few days around late June, and at this time a double vertical migration appeared with the second instars leading and following the migration of fourth instars. We speculate that these changes in the migration of second instars are driven by seasonal shifts in predation risk from larval cisco (Coregonus artedi) and by the need to minimize spatial overlap with the larger fourth instars.

scholarly journals Variation of Zooplankton Mean Volume Backscattering Strength from Moored and Mobile ADCP Instruments for Diel Vertical Migration Observation

2019 ◽  
Vol 9 (9) ◽  
pp. 1851 ◽  
Author(s):  
Angga Dwinovantyo ◽  
Henry M. Manik ◽  
Tri Prartono ◽  
Susilohadi Susilohadi ◽  
Tohru Mukai
Keyword(s):  
Vertical Migration ◽  
Acoustic Doppler Current Profiler ◽  
Target Strength ◽  
Zooplankton Species ◽  
North Sulawesi ◽  
Lembeh Strait ◽  
Backscattering Strength ◽  
Current Profiler ◽  
The Mean ◽  
Sound Scattering Layer

Zooplankton can be detected by using acoustic Doppler current profiler (ADCP) instruments through acquiring the mean volume backscattering strength (MVBS) data. However, the precision of the backscattered signal measured by single ADCP measurement has a limitation in the MVBS variation of zooplankton. The objectives of this study were to analyze the MVBS and vertical velocity from ADCPs at the same time and location for zooplankton’s daily vertical migration (DVM) observation. Measurements were conducted in Lembeh Strait, North Sulawesi, Indonesia. Instruments used included a moored ADCP 750 kHz and a mobile ADCP 307.2 kHz. High MVBS value was found at 11.5–16 m depths and was identified as the sound scattering layer (SSL). The DVM patterns in the SSL displayed significant differences over time and had good relationships with the diurnal cycle. Theoretical target strength (TS) from the scattering models based on a distorted-wave Born approximation (DWBA) was estimated for Oithona sp. and Paracalanus sp.; the two dominant species found in the observed area. However, ΔMVBS and ΔTS proved that the dominant zooplankton species were not the main scatterers. The strong signal in SSL was instead caused by the schools of various zooplankton species.

Krill diel vertical migration fine dynamics, nocturnal overturns, and their roles for aggregation in stratified flows

2008 ◽  
Vol 65 (4) ◽  
pp. 574-587 ◽  
Author(s):  
M Sourisseau ◽  
Y Simard ◽  
F J Saucier
Keyword(s):  
Water Column ◽  
Vertical Migration ◽  
Acoustic Doppler Current Profiler ◽  
Day Length ◽  
Data Set ◽  
Vertical Movements ◽  
Lawrence Estuary ◽  
Diel Vertical Migrations ◽  
Current Profiler ◽  
Feeding Bout

A set of high-resolution observations on short-term dynamics of krill diel vertical migrations (DVM) in the St. Lawrence Estuary are presented here, including vertical mass transfer measurements from multifrequency echo sounding coupled with stratified net sampling and tracers of individual vertical movements from stomach pigments over a 72 h period. The data set is supplemented by vertical migration speeds and biomass diel patterns from ADCP (acoustic Doppler current profiler) time series lasting up to 3 months. All krill always rapidly migrated to the surface in synchrony at sunset. Soon after the ascent, fed krill started to swim downward. A scattering layer was then formed at their daytime depth with sometimes a significant backscatter at intermediate depths, especially around midnight. A reorganisation in the upper water column then occurs, likely for a predawn feeding bout. At dawn, the krill mass still feeding in upper water column synchronously swam downward to their daytime depth. This nocturnal asynchronous vertical behaviour, conforming to the DVM hunger-satiation hypothesis, repeated between August and October in two different years, the DVM timing being determined by day length.

scholarly journals Acoustic Doppler current profiler observations of migration patternsof zooplankton in the Cretan Sea

Ocean Science ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 783-800 ◽  
Author(s):  
Emmanuel Potiris ◽  
Constantin Frangoulis ◽  
Alkiviadis Kalampokis ◽  
Manolis Ntoumas ◽  
Manos Pettas ◽  
...  
Keyword(s):  
Vertical Migration ◽  
Eastern Mediterranean ◽  
Vertical Motion ◽  
Acoustic Doppler Current Profiler ◽  
Aegean Sea ◽  
Lunar Cycle ◽  
Migration Patterns ◽  
Current Profiler ◽  
Continuous Presence ◽  
Cretan Sea

Abstract. The lack of knowledge of the mesopelagic layer inhabitants, especially those performing strong vertical migration, is an acknowledged challenge. This incomplete representation leads to the exclusion of an active carbon and nutrient pathway from the surface to the deeper layers and vice versa. The vertical migration of mesopelagic inhabitants (macroplanktonic and micronektonic) was observed by acoustical means for almost 2.5 years in the epipelagic and mesopelagic layers of the open oligotrophic Cretan Sea (south Aegean Sea, eastern Mediterranean) at the site of an operational fixed-point observatory located at 1500 m depth. The observed organisms were categorized into four groups according to their migration patterns. The variability of the migration patterns was inspected in relation to the physical and biological environmental conditions of the study area. The stratification of the water column does not act as a barrier for the vertical motion of the strongest migrants that move up to 400 m every day. Instead, changes in light intensity (lunar cycle, daylight duration, cloudiness) and the presence of prey and predators seem to explain the observed daily, monthly and seasonal variability. The continuous presence of these organisms, which are capable of vertical motion despite the profound circulation variability at the site of the observatory, implies their presence in the broader study area. The fundamental implications of the above regarding biogeochemical processing in oligotrophic seas due to the intimate link between the carbon (C) and nutrient cycles, are discussed.

scholarly journals Zooplankton diel vertical migration in the Corsica Channel (north-western Mediterranean Sea) detected by a moored acoustic Doppler current profiler

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 631-649 ◽  
Author(s):  
Davide Guerra ◽  
Katrin Schroeder ◽  
Mireno Borghini ◽  
Elisa Camatti ◽  
Marco Pansera ◽  
...  
Keyword(s):  
Water Column ◽  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Temporal Distribution ◽  
Acoustic Doppler Current Profiler ◽  
Western Mediterranean ◽  
Late Winter ◽  
Western Mediterranean Sea ◽  
Current Profiler ◽  
Deep Layers

Abstract. Diel vertical migration (DVM) is a survival strategy adopted by zooplankton that we investigated in the Corsica Channel using acoustic Doppler current profiler (ADCP) data from April 2014 to November 2016. The principal aim of the study is to characterize migration patterns and biomass temporal evolution of zooplankton along the water column. The ADCP measured vertical velocity and echo intensity in the water column range between about 70 and 390 m (the bottom depth is 443 m). During the investigated period, zooplanktonic biomass had a well-defined daily and seasonal cycle, with peaks occurring in late winter to spring (2015 and 2016) when the stratification of the water column is weaker. Zooplanktonic biomass temporal distribution in the whole water column is well correlated with biomass of primary producers, estimated with satellite data. Zooplanktonic blooming and non-blooming periods have been identified and studied separately. During the non-blooming period zooplanktonic biomass was most abundant in the upper and the deep layers, while during the blooming period the upper-layer maximum in zooplanktonic biomass disappeared and the deep layer with high zooplanktonic biomass became thicker. These two layers are likely to correspond to two different zooplanktonic communities. The evolution of zooplanktonic biomass is well correlated with chlorophyll, with phytoplankton biomass peaks preceding the upper-layer secondary production by a lag of about 3.5 weeks. Nocturnal DVM appears to be the main pattern during both periods, but reverse and twilight migration are also detected. Nocturnal DVM was more evident at mid-water than in the deep and the upper layers. DVM occurred with different intensities during blooming and non-blooming periods. One of the main outcomes is that the principal drivers for DVM are light intensity and stratification, but other factors, like the moon cycle and primary production, are also taken in consideration.

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