Diurnal and Seasonal Changes in Distribution of Two Planktonic Ostracods, Conchoecia elegans and Conchoecia alata minor

Abstract

Diurnal and seasonal changes in the distributions of two planktonic ostracods, Conchoecia elegans Sars and C. alata minor McHardy, have been considered in relation to changes in the temperature, salinity, oxygen concentration, and subsurface light in Indian Arm, British Columbia. Both species occurred frequently throughout the water column except near the surface. There is the suggestion (reinforced by data from other B.C. inlets) of an upper temperature limit for C. alata minor, which is lower than for C. elegans. Salinity and dissolved oxygen environments appear to have been similar for the two species. An upinlet displacement of both species-populations which took place in the early months of the year could possibly have been initiated by water which had intruded into the depths of Indian Arm. The vertical distributions of the two species showed statistically significant changes which varied with time of day, season, and geographic position. It was not possible to show that the depth of daylight distribution was strongly related to the penetration of light.

Planktonic ostracods from the Canary Island Region; their depth distributions, diurnal migrations, and community organization

“…Hure (1961) and Leveau (1965) demonstrated both diurnal and seasonal vertical migrations in the common Mediterranean halocyprids, but very few species were abundant enough for them to reach firm conclusions. McHardy & Bary (1965) found diurnal and seasonal migrations in the only two species found in the British Columbian Fjord%. provided some incidental information from his examination of the distribution of halocyprids in relation to the thermocline off the Moroccan coast, but his samples were only taken at night from depths of 50-105 m. The region of the Canary Islands is extremely rich in halocyprid species (Granata & Caporiacco, 1949) and is, therefore, a particularly suitable area for the investigation of their depth distributions.…”

Morphological and taxonomic diversity of mesozooplankton is an important driver of carbon export fluxes in the ocean

“…Siphonophorae and Salpidae also realize diel vertical migrations Lüskow et al, 2019). DVM was shown for several genus of ostracods (Kaeriyama & Ikeda, 2002;McHardy & Bary, 1965;Ursella et al, 2018). Even though DVM is a process known to significantly contribute to the biological pump (Steinberg et al, 2008), no significant positive correlation was found between carbon export and module A relative abundances.…”