A Closer Look at the Bathypelagic Zone

selim12 February 1, 2024 0 Comments

The Bathypelagic zone is a part of the ocean, just below the Mesopelagic Zone and above the abyssopelagic zone; starting from depths between 1000 meters to up to 4000 meters. It’s also known as the midnight zone due to the lack of light!

Table of Contents

Depth and Characteristics Of Bathypelagic Zone:

The temperature here is 14°C with 35 g/kg salinity. This part of the ocean has no light and bioluminescence is minimal. The hydrostatic pressure is ranging from 100-400 atmospheres(with 1 atm for every 10 meters depth). These pressure metrics have still been consistent during the last 8000 years. The depth range is 1000 to 4000 meters. This zone lacks light sunlight so hydrothermal vents are responsible for the ecosystem and the food chain through chemosynthesis. Most of the carbon material is produced in the upper zone, the mesopelagic zone.

The Biodiversity:

This part of the ocean has many seamounts and mid-ocean ridges made up of accumulated sediment providing habitat for bathypelagic fishes and benthic invertebrates. Despite the currents being very slow at these depths. Still, the shape of seamounts interrupts the currents creating plankton in the seamount region. The presence also of hydrothermal vents in these depths has great importance for providing energy and food for the animals there through a process called chemosynthesis(detailed in the link). They also help in the precipitation of minerals in the seafloor. A big part of the biogeochemical process is dependent upon the input of organic matter for the above regions called the marine snow transported also by the chemical reaction of the hydrothermal vents.

Adaptations of Bathypelagic Organisms:

The bacteria here like heterotrophic eukaryotes have been limited due to depth. Bethnic organisms tend to have limited to no bioluminescence. The living creatures here such as deep-water anglerfish, gulper eel, amphipods, and dragonfish have weak muscles, soft skin, and slimy bodies to withstand pressure while some fish have transparent skin and small eyes. Living here is so difficult for fish species, they adapted low metabolism to conserve energy. But whale falls present high activity in these depths attracting the Bathypelagic community. Diel vertical migration is also present due to the movement of the upper zone like the Sthenoteuthis squid who migrate individually for 4-5 hours toward the surface.

Exploration and Research Challenges:

This part of the ocean is understudied due to hard access. But continental margins are researched, alongside ocean ridges and seamounts due to advanced technology such as the development of high-performing ROVs. For info, the first expedition to the Bathypelagic zone was back in 1977 led by Jack Corliss. Recent advancements include also autonomous underwater vehicles (AUVs), and independent gliders and floats.

True Facts about Bathypelagic Zone:

-The majority of organic carbon is produced here.

-The sediment of the Bathypelagic zone is rich with CaCO3 content and burial.

-A type of archaea, Crenarchaeaota is linked to dissolved inorganic carbon fixation.

Views of benthic macrofauna associated with the reef

In more recent years, More efforts are needed to further study these environments. Some important groups of bacterial grazers include Rhizaria, Alveolata, and Fungi, which are classified as uncertain.