Diel and lunar cycles of vertical migration extending to below 1000 m in the ocean and the vertical connectivity of depth‐tiered populations

Abstract

We measured diel migration with 11 acoustic Doppler current meter profilers and consistently found diel and lunar cycles of vertical migration from 250 m down to the bathypelagic (. 1000 m). These measurements come from year-long deployments in eight locations within the Gulf of Mexico. Diel vertical migration could be characterized, in depth and time, by a pulse of maximum vertical migration activity (PMV), which has a nearly fix phase relation to sunrise and sunset modulated by the lunar cycle. The vertical velocity of migrating biota is in the same direction as the PMV propagation, but it is significantly slower. This difference in velocity implies that the PMV cannot represent the migration pattern of one single population. The lunar cycle is evident down to 1000 m, where the upward migration delays in phase with the full moon. The extension of the diel and lunar cycles over 1000 m depth together with the difference in vertical migration velocity indicate that the surface irradiance signal is transmitted to bathypelagic depth by synchronized depth-tiered populations. A model in which particulate organics are recycled at different depths, similar to a bucket brigade, is consistent with these observations. This daily vertical connectivity is expected to affect the vertical transport of carbon down to the bathypelagic.

Wintertime water dynamics and moonlight disruption of the acoustic backscatter diurnal signal in an ice‐covered Northeast Greenland fjord

“…In addition to water dynamics, another disrupting factor for DVM was the moon cycle. Most studies on lunar disruption of DVM were conducted either at subtropical latitudes [ Hernández‐León et al ., ] or in the deep sea [ Mercier et al ., ; Ochoa et al ., ]. In general, DVM patterns are known to correlate well with the moon phase [ Ochoa et al ., ; van Haren and Compton , ].…”

“…Most studies on lunar disruption of DVM were conducted either at subtropical latitudes [ Hernández‐León et al ., ] or in the deep sea [ Mercier et al ., ; Ochoa et al ., ]. In general, DVM patterns are known to correlate well with the moon phase [ Ochoa et al ., ; van Haren and Compton , ]. Herbivorous zooplankton species are typically observed maintaining deeper positions in the water column during the full moon phase, whereas they are more abundant in the surface water layer during new moon phase.…”

“…To correct for beam geometry we derived volume backscatter strength (VBS) S v in dB from echo intensity following the procedure described by Deines [1999]. The ADCP-derived vertical velocity has also been used to study rates of zooplankton diel vertical migration [e.g., Plueddemann and Pinkel, 1989;Cottier et al, 2006;Ochoa et al, 2013]. In our data set the ADCPs velocity precision and resolution were 60.5% and 61 mm/s, respectively.…”

Vertical redistribution of zooplankton in an oligotrophic lake associated with reduction in ultraviolet radiation by wildfire smoke

“…In fact, many different environmental factors can affect DVM, including UV radiation [Leech and Williamson, 2001]. Various natural events and processes can also alter "standard" DVM, including eclipses [Kampa, 1975], phases of the Moon [Ochoa et al, 2013], ice cover [Wallace et al, 2010], and water turbidity [Frank and Widder, 2002;Rose et al, 2012].…”

Lunar cycles affect common dolphin Delphinus delphis foraging in the Southern California Bight

“…It appears that mesopelagic fish seek refuge in dark waters and at the edges of deep oxygen minimum zones which are inaccessible or un suitable for their more aerobic and visually oriented predators (Seibel 2011, Netburn & Koslow 2015. Both absolute light levels, as well as the rate of change in light levels, have been proposed as triggers for changes in the behavior of vertical migrators, and there also seems to be an endogenous rhythm component to vertical migration (Benoit-Bird et al 2009a, Ochoa et al 2013. Lanternfish (family Mycto phidae), in particular, play an important role in SCB ecosystems (Davison et al 2015), are abundant in DSLs, and are known to occur at much lower densities in the epipelagic zone during nights surrounding the full moon versus dark nights of the new moon (Clarke 1973).…”