Pelagic
Demersal zone
Vagile benthos
Sessile benhtos
MURTER - CROATIA
The demersal zone is the part of the sea comprising the water column that is
near to and is significantly affected by the seabed and the benthos. The demersal
zone is just above the benthic and forms a layer of the larger profundal zone.
The pelagic zone represents a water column that goes from the surface of the
sea almost to the bottom. Pelagic life decreases with increasing depth. It is
affected by light intensity, pressure, temperature, salinity, the supply of dissolved
oxygen and nutrients, and the submarine topography.
The benthic (seabed) zone varies: there are mountains, trenches, flat muddy
areas, sandy areas and rocky areas, caves.
The term benthos is derived from the Greek, meaning 'depths of the sea' and
refers collectively to organisms which live on, in, or near the bottom of the sea.
Most benthos feed on food as it floats by or scavenge for food on the ocean
floor. Some organisms live in the mud, some crawl or swim along the bottom
and some anchor themselves to the seabed floor.
The benthic community includes a wide range of plants, animals and bacteria.
They are classified into 3 categories: infauna - organisms that live in the
sediment; epifauna - organisms which either attach to the bottom or substrate,
move within the sediment, or live on the sediment surface; demersal - fish that
feed on the benthic infauna and epifauna.
Sessile organisms are attached to the seabed or to objects on or near the
seabed.
Vagile benthos is applied to animals that can freely move about the seabed.
A few introductory words
Here you can browse some images with basic information about the fauna living in the waters of Murter and Kornati.
I took the pictures using two cameras: Olympus C-7070WZ and S-550 UZ, and I must say that the latter, although newer, is a big disappointment because of
the bulky underwater housing. When you choose a camera for underwater shooting make sure that you start by searching for a housing that is small and
handy, as zoom in the water is not very helpful and also make sure that the camera has a good flash and good shake control. Even small movements due to
waves or currents can blur the photo and while you still try to get yourself to be still, your trophy may flee.
You should also carefully choose the person with whom you dive when taking pictures under water. It should be your usual diving partner or someone who
also takes photographs or at least someone who is diving slowly. If you are diving with someone who just buzzes along the bottom, you'll probably miss the
tons of good staff because you will either not be able to notice it, or you will always take care not to lose your partner from sight and you will probably soon
be out of air.
Personally, I prefer diving wearing a left glove because it allows me to grasp to the bottom without danger to puncture, burn or cut my skin, while my right
hand is free for taking pictures and playing with camera controls. Always be careful when sneaking to some beautiful trophy you just noticed, because of
possible injuries while you're focused on it. Bear in mind that there are some poisonous animals in the sea that have good camouflage and you just stumbled
to their territory.
DIVING CENTER KORNATI NAUTILUS