#marinelifefacts

[jkfishworld]

Tube worms, like this gorgeous feather duster, as sessile organisms. This means they attach themselves to whatever surface they’re on, and (unless removed by an external force), stay on that surface for the rest of their life!

[ladyblue-laragazzadelmare]

#OceanFact n. 1

𝗭𝗼𝗼𝗽𝗹𝗮𝗻𝗸𝘁𝗼𝗻 𝗺𝗮𝗸𝗲𝘀 𝗱𝗮𝗶𝗹𝘆 𝗺𝗶𝗴𝗿𝗮𝘁𝗶𝗼𝗻𝘀 𝗳𝗿𝗼𝗺 𝘁𝗵𝗲 𝗱𝗲𝗲𝗽 𝘄𝗮𝘁𝗲𝗿𝘀 𝘁𝗼 𝘁𝗵𝗲 𝘀𝘂𝗿𝗳𝗮𝗰𝗲.

Zooplankton, the tiny crustaceans at the base of the food web, makes the so-called "Diel Vertical Migrations" (DVM). Usually, they tend to change depth during the day: during nighttime, they tend to be at the surface, while during the day they stay at greater depths.

This behaviour has been described first in the 19th century (Cuvier, 1817; Schmidtlein, 1879), both in freshwater lakes and in the oceans. Researchers noticed the difference in abundance of the zooplankton from day to night.

The such complex practice has so been studied for almost 200 years.

Different types of vertical migrations have been described, with different periodicities (daily, seasonals) areas of occurrence and biological significance. Although great variability exists, two of the main reasons attributed to this behaviour are the avoidance of predators that mainly rely on vision (by staying in deeper waters during the day) and the advantage of a high concentration of food at the surface (by migrating to the surface during nighttime).

The evolution of these behaviours for a simple group of species forced other levels in the food web to evolve a similar pattern. This phenomenon is called coevolution. In this way, predators learnt to make the same migrations to feed on the high densities of zooplankton.

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𝗥𝗲𝗳𝗲𝗿𝗲𝗻𝗰𝗲𝘀 𝐚𝐧𝐝 𝐬𝘂𝗽𝗽𝗹𝗲𝗺𝗲𝗻𝘁𝗮𝗿𝘆 𝗺𝗮𝘁𝗲𝗿𝗶𝗮𝗹:

Bandara, K., Varpe, Ø., Wijewardene, L., Tverberg, V., & Eiane, K. (2021). Two hundred years of zooplankton vertical migration research. Biological Reviews, 96(4), 1547-1589. https://doi.org/10.1111/brv.12715

Dodson, S. (1990). Predicting diel vertical migration of zooplankton. Limnology and Oceanography, 35(5), 1195-1200. https://doi.org/10.4319/lo.1990.35.5.1195

Hays, G. C. (2003). A review of the adaptive significance and ecosystem consequences of zooplankton diel vertical migrations. Migrations and dispersal of marine organisms, 163-170. extension://elhekieabhbkpmcefcoobjddigjcaadp/http://www.seaturtle.org/.../hays_Hydrobiologia2003.pdf

Natural World Facts (2022). The Great Vertical Migration.

Image representing the migrations from Bandara et al., 2021.

Video cut from "Natural World Facts (2022). The Great Vertical Migration". See the full video above for amazing facts!