Murcia has an exceptionally beautiful and diverse coastline. Stretches of cliffs, wild and inaccessible, give way to sandy beaches and low-rising rock formations.
Picturesque hidden coves punctuate the landscape, while reefs, islets and islands are scattered along the whole length of coast. The marine landscape itself is equally diverse - its seabeds boast an impressive range of marine life.
The marine ecosystem is made up of a physical medium or habitat – the seas and the oceans – and a variety of living organisms – marine plants and animals – that are interdependent on each other and their environment.
Sea creatures rely heavily on particular environmental conditions, including the temperature, salt content and density of the water, the amount of light coming through and the movement of the water, and are affected by any changes.
Every species, after thousands of years of natural selection, has adapted to certain conditions, and it is in these that they are born and in which they grow and reproduce successfully.
They will be pushed out by other, better adapted species from places with conditions that do not suit them.
In the marine ecosystem the greatest changes are in depth: with greater depth, light, temperature and surf decrease, and pressure increases.
The changes brought about by the shape of the seabed (cracks, bends, caves, practically vertical walls) and its features (rocks, sand, boulders) only serve to compound any changes in depth.
But this wide range of environmental conditions is nature’s secret way of giving rise to the huge range of species, shapes and colours that can be found in our oceans and seas.
The plants and animals that live mid-water are referred to as plankton and nekton, and those that live in close contact with the seabeds are know as benthos.
If we take a trip underwater we can see that seabeds and waters that have not been polluted harbour groups of marine plants and animals that are of great ecological importance, and they form little known but very fragile and beautiful landscapes.
Some of these seascapes are just as important to ecology as land forests, but because people are unaware of their existence they don’t fight for their conservation as they do with landscapes above, which are easy for everyone to see.
The body of blue water is the most impressive marine landscape, completely enveloping the diver, and creating a sense of weightlessness that makes us feel as though we are flying.
The creatures you can see in this extensive and sparsely populated blue expanse are plankton and nekton. The microscopic plankton look like cloudy water, but the beautiful, almost translucent siphonophores, salpas and jellyfish can easily be seen by the naked eye.
The fish, mammals and sea reptiles we can see are those that come in to the coast for shelter or food.
Our attention is at once drawn to the contrast between the rocky and the sandy seabeds. To most divers the rocky beds are more attractive, because they combine sharp features with an ever-changing landscape, and the evocative shapes and colours of the many plants and vegetables that live in them.
Thanks to the stability of the beds, they are covered, almost completely, by an unbroken layer of organisms that have developed vast numbers of adaptive responses for finding food and keeping, or even increasing, their hard-won space.
The clear rocky seabeds house the plant kingdom and in the south east of Spain they reach depths of more than 30 metres.
Both the diver and the swimmer are immersed in this landscape as soon as we enter the water and the predominance of vegetation is very marked: the high light levels enable plants to contend successfully with animals and they take over more of the available space.
In fact, to divers who are not very observant, these seabeds can appear a uniform carpet of plants, and the only creatures that attract their attention are the spectacular fish, some with almost tropical colours, that abound among the plants.
Where the coast has been preserved, you will be surprised by the number and size of the fish – bream, mojarra, salpa, rainbow, ornate and green wrasse to name but a few.
These underwater ‘gardens’ only appear homogenous and uniform on the surface and in this tangle of plants a large number of molluscs, crustaceans and worms find shelter and food. There are, albeit in smaller numbers, sponges, coelenterates, bryozoans and echinoderms – a surprising range and variety of fauna.
Sea walls are another typical and attractive marine landscape. The rocks go down to different depths in different places along the coastline.
At these depths of subdued light there is not so much vegetation, and it is the colours of the sponges, coelenterates, molluscs, worms, echinoderms and sea squirts that charm the diver’s eye.
Also important is the landscape of coves, tunnels and caves, the walls of which harbour a delicate and fragile community of organisms. The explosion of colour is due to the almost total predominance of invertebrates and certain species of red vegetation.
The colours that stand out are the blues, reds, yellows and pinks of the sponges; the oranges, yellows and reds of the anemones and the scarlet coral. There is the delicate beauty of the bryozoans, along with the violets, whites, copper and blacks of the impressive opisthobranch molluscs.
Then there are the reds, browns, blacks and oranges of the starfish, sea urchins and sea cucumbers, and the terracotta, coppers and browns of the lobster and hermit crab shells. You can also come across groupers, sea bass, conger eels, swallowtail seaperch and rockling, all native to these waters.
At depths of more than 35 metres, where certain conditions of low light and current, and relatively cool water, are present, an incredibly beautiful landscape opens up: the coral reef.
Red calcareous vegetation makes up most of the embedded layer of this community, in which there is a proliferation of vast numbers of different species of sponge, tube worms with beautiful plumes, sea squirts and large colonies of bryozoans.
All of this is, in part, overshadowed by the incredible size of the tree-like gorgonian coral in the oldest reefs. This forest provides shelter and food for a wide variety of moving fauna, including worms, beautiful molluscs, with or without shells, crustaceans such as lobster, and fish including the colourful swallowtail seaperch.
For no good reason, these are afraid of the morays and the imitation large-scaled scorpion fish and perhaps even the groupers. They swim about elegantly in mid water, but always at a distance and forever watchful, ready to dart back to their hole or into deeper waters.
In comparison, the sandy beds are not as attractive as the rocky ones, but buried in their grains of sand is a rich variety of fauna that will surprise anyone who thinks that these beds are uninteresting and monochrome settings.
They are not stable because they are constantly shifting with the tide, and so there is very little plant life, and most of the animals, which tend to be molluscs, worms, crabs and sea urchins, bury themselves in the sediment.
It is here that you will see fish such as red mullet, sling fish, torpedo rays, sole and, if luck is on your side, perhaps an eagle ray, whose majestic flight will impress you as it unwillingly flees the disturbance you have caused.
Sandy beds at a depth of less than 40 metres are covered with plants (oceanic Posidonia) which became native to the marine environment a hundred million years ago and grow in underwater meadows or lawns.
These undulating green cloaks play an important role in maintaining the coastal environment, due to the large area they cover and the great numbers of plant and animal species that live on or around their leaves and rhizomes.
The Posidonia meadow in particular is as important ecologically as land forests because of its size, and there are vast numbers of this species in the Mediterranean.
Its crystal clear waters, the diverse shapes and landscape of its beds, not to mention the wide range of species that live in them, confer on the marine landscape of Murcia a special beauty and ecological value. We must constantly strive to preserve it.