Independent Scuba

Intro to the Med

The environment in the Mediteranean Sea is unique. The geography of it has created conditions that have developed over millions of years into what we have today – a unique and fragile environment.First time visitors to the Mediterranean are sometimes surprised when they have a first look under the surface. It does not look like the coral reefs of tropical waters and neither does it look like the fertile waters of Northern Europe. There are good reasons for this – the conditions in the Med are quite unique.

Oceanographic overview

The Mediterranean Basin was formed some 20 million years ago and there were several seas within it that evaporated occasionaly leaving behind gigantic salt marshes. At this time the western opening to the Atlantic were completely closed. An estimated 5 million years ago, a massive earthquake opened up the strait of Gibraltar and the Atlantic started to pour in and it took over a century to fill the basin to form the Mediterranean Sea. This connection is still today the only significant influx of water into the Med. A current of approx 4 km/h runs some 75 m below the surface, bringing in nutrients from the Atlantic. As the sun heats the water evaporation starts and the water becomes saltier and heavier. This water then flows out through the Strait of Gibraltar again – a process that supposedly takes about 80 years.

The Mediterranean

This means that the sea has a relatively low level of nutrients and it is also the reason behind the excellent visibility. Lots of plankton means low visilbility and although this is rare there are areas with a more dense plankton population. This is usually due to river flows or growth due to a reaised level of fertilizer in the water. The Med itself consists of several seas – the Alboran Sea, The Gulf of Lyons, The Ligurian Sea, The Adriatic, The Aegean, The Gulf of Trieste, The Ionian Sea, The Sea of Marmara and the Levant Sea. The deepest parties the Ionian Sea with a maximum depth of 5121 m. The average depth of the Med is as deep as 1500 meters! Thus, there is only a small area of the sea that has actually been explored by divers.

Biological overview

The water temperature never goes below 10 degrees and although this is not very cold it is still too low for coral such as cup corals and red coral. Other colourful species include various types of sponges and bryozoans. The diversity of the Med is lower than that of the neighbouring Atlantic and the Red Sea. This is due to the low plankton levels and the fact that the sea is relatively young. The older Med, now long since dried out, has traces of coral reefs but they disappeared with the water. Divers with keen eyes will see a lot of small marine life such as nudibranchs and flatworms – some very colourful. Those who wish to see bigger species have to depend more on luck. Large pelagic species do exist but are rarer than in other seas. The chance is always there however and this year both eagle rays, sunfish and dolphins have been spotted by divers.

Flying Gurnards

Seeing a shark diving in the Med is very unusal. Some say that we should be thankful for that given the size of the sharks in the Med. Although rare, there are recent recordings of Hammerheads off Wied-iz Zurrieq. Other shark species include the Blue Shark, The Great White, Mako and Thresher shark. All these have been caught and/or observer off Malta relatively recently.

Environmental issues

One cannot discuss the Mediterranean without mentioning the enormous historical relevance of the area. Here is the birthplace of the Greek, Roman and Arab cultures as well as three world religions – Judaism, Christianity and Islam. Needless to say, this extensive human activity has had a negative impact on the fragile environment. Many of the countries have highly developed fishing industries and the heavy traffic causes other types of pollution.

This has been recognised in several countries and Marine Reserves have been created with excellent results. More are needed however but the political challenge of managing a common resource shared by so many countries is enormous. There are talks about creating a marine reefs to thrive. There are other types of corals however reserve also in Malta but nothing is yet decided.

There opening of the Suez Channel has had a major impact with species migrating from the Red Sea into the Med. On average one species per year has established itself since then. Most of them are in the Eastern Mediterranean but some are moving west – some unusal ones have also been spotted in Malta. It seems that it is considerably easier for the Red Sea species to colonize the Med than the other way around. One reason for this is that the species in the Red Sea are much more specialised given the very tough competition faced by inhabitants of coral seas. In Malta we have, for example, spotted a trumpetfish in Cirkewwa during a nightdive recently.

The Mediterranean environment is in many aspects unique. Divers visiting get spoilt by the clear waters and there are excellent photo opportunities. It is an environment you cannot experience anywhere else on Earth, created by very special and unique circumstances. Next time you dive in the Med – take your time and look for the details that are unique and you be rewarded with great diving.