Aquatic Ecology374 First Term of year Nuha AL-Abdulhadi Dr.promy lab 4

Benthos

The term Benthos :comes from the Greek noun which means (depths of the sea) :is the community of organisms which live on, in, or near the seabed, also known as the benthic zone.This community lives in or near marine sedimentary environments.Greekseabedbenthic zone What is the Bent hos

It includes Plants(phytobenthos) and animals(zoobenthos) such as sea anemone and sponges, creeping creatures such as crabs and sea cucumbers, and burrowing animals such as worms. sea anemonespongescrabssea cucumbers

Because light does not penetrate very deep in ocean-water, the energy source for deep benthic ecosystems is often organic matter from higher up in the water column which drifts down to the depths. This dead and decaying matter sustains the benthic food chain; most organisms in the benthic zone are scavengers or detritivoresdead and decaying matterfood chainscavengersdetritivores

Many organisms adapted to deep-water pressure cannot survive in the upper parts of the water column. The pressure difference can be very significant.water column

 The importance of benthos : 1)Benthic organisms play an important role in food chains, including as food for humans, and some play a critical role in the breakdown of organic matter. 2)Some benthic zones, such as areas of coral reefs, kelp forests, and, help to buffer wave action along coastlines, providing storm protection. 3)The benthic zone provides an area for spawning, foraging, and refuge for various fish species, and benthic habitats function in nutrient cycling and removal of contaminants from the water, such as with the removal by filter feeders (scallops, mussels, and so on) of pollutants, organic matter, and sediments.food chainscoral reefskelpfishscallopsmussels

We can divide the Benthos also to : 1- Macrobenthos.These animals live on rocks, sediment, debris and aquatic plants during some period in their life. The benthos include crustaceans such as crayfish, mollusks such as clams and snails, aquatic worms and the immature forms of aquatic insects such as stonefly and mayfly nymphs). Macrobenthos comprises the larger, more visible, benthic organisms that are greater than 1 mm in size. Some examples are comprises the larger, more visible, benthic organisms that are greater than 1 mm in size. Some examples worms, sea anemones, corals, sponges, sea squirts, and larger crustaceans such as crabs, lobsters.

 A sea squirt being used as a substrate for a nudibranch's spiral eggsea squirt nudibranch

Microbenthos Microbenthos comprises microscopic benthic organisms that are less than 0.1 mm in size. Some examples are bacteria, diatoms, ciliates, amoeba, flagellates. bacteriadiatomsciliatesamoeba flagellates

Marine diatoms

Ciliate stentor roseseli

flsgellate

Meiobenthos comprises tiny benthic organisms that are less than 1 mm but greater than 0.1 mm in size. Some examples are nematodes, foraminiferans, water bearers, gastrotriches and smaller crustaceans such as copepods and ostracodesnematodes foraminiferanswater bearers gastrotrichescrustaceanscopepodsostracodes

Ammonia tepida

COPEPOD

Benthos can also be classified as : A-Zoobenthos Zoobenthos comprises the animals belonging to the benthos. B-Phytobenthos Phytobenthos comprises the plants belonging to the benthos, mainly benthic diatoms and macroalgae (seaweed). By location A-Epibenthos Epibenthos lives on top of the sediments. B-Hyperbenthos Hyperbenthos lives just above the sedimentdiatomsmacroalgaeseaweed The start fish is a benthos animal mussles The start fish is a hyperbenthos

Hyperbenthos Ex:STAR FISH : 1- Most starfish typically have five rays or arms, which radiate from a central disk 2-The bodies of starfish are composed of calcium carbonate components

Ex:mussles Epibenthos

A.C - Hypobenthos: These are animals that live upon or in the bottom of the deep sea, below the 500- fathomline. One of the most remarkable results of the exploration of the deep sea is the discovery that the bottom, even under more than five miles of water, supports a rich fauna of characteristic animals, living under conditions which had long been supposed. Their bodies support a pressure which, in the greatest depths, is more than five tons to the square inch, and they live in water that is always near the freezing- point, in total darkness except for the light which they themselves produce by means of luminous organs. Since plants are completely absent in the depths, the only ultimate source of the food of these animals is the rain of (dead plants and animals) which is constantly falling upon them from the higher levels Hypobenthos

Epibenthos: Epibenthos are animals living on or immediately above the seafloor(on top of the sediments). Some are attached to the substrate, others are mobile. Examples are sponges, corals and seastars. A particularly interesting mobile group is the sea cucumbers which have swimming representatives in the deep-sea

Sea cucumbers have hundreds of tiny suction-cup tube feet that they use to crawl across the sea floor

Benthic Fish Species benthic fish Fish that live on or near the sea-bottom, irrespective of the depth of the sea. Many benthic species have modified fins, enabling them to crawl over the bottom; others have flattened bodies and can lie on the sand; others live among weed beds, rocky outcrops, and coral reefs.

They either lie-and-wait as ambush predators, maybe covering themselves with sand or otherwise camouflaging themselves, or move actively over the bottom in search for food.[3] Benthic fish which can bury themselves include flatfish and sting rays.

Demersal fish inferior" mouth, which means that the mouth is pointed downwards; this is beneficial as their food is often going to be below them in the substrate. Those bottom feeders with upward-pointing mouth to seize swimming prey.

an adult, a flounder changes its habits and camouflages itself by lying on the bottom of the ocean floor as protection against predators. As a result, the eyes are then on the side which faces up. The side to which the eyes migrate is dependent on the species type.

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