INTRODUCTIONTO THE DEEP SEA ENVIRONMENTIn this essay we shall discuss several aspects of thedeep sea environment. The main focus will be on theenvironment below the Mesopelagic Zone that extendsdown to 2000 meters below sea level with an emphasison the environment in the Bathypelagic andAbyssalpelagic Zones. We will examine the sourcesof evidence for a discussion of this deep sea environmentby looking at some of the techniques man usesto gather information there. This will be followed bya description of some of the determining conditions inthese regions with a note on geology, sediments,a brief discussion of the deep water masses, a descriptionof marine life to be found in the deep sea environment,its adaptations and challenges with a specialnote on hydrothermal vents (although at an averagedepth of 2100 meters they are just within our discussionzone), hydrocarbon seeps and a final conclusionabout the overall importance of thedeep sea environment for mankind.Firstly, why study the deep sea environment atall? The abyssal plains are dark and seem devoid oflife or interest but nothing could be further from thetruth. Abyssal areas represent over 90% of the benthosand over 80% of ocean lies below 3000 meters. New discoveriesare being made and these could greatly influenceour future. The deep sea is a repository ofscientific information and resources that caninfluence us in the fields of medicine, chemistry, physics,biology, feeding the world's expanding population andconservation. The deep sea is in fact the largest ecosystemon Earth. Let us first examine the methods ofevidence collection.THE COLLECTION OF EVIDENCEThere are many techniques and devices that havebeen used to explore the depths and gather informationranging from the days of dropping lead weights(line sounding) over the side of ships, to echo soundingsince World War I, to the invention of scuba gear (notuseful at our depths under discussion), to the use ofGeological Long Range Inclined Asdic (GLORIA). Sidescansonar and continuos seismic surveying methods dogive us a wealth of information. In addition a range ofsimple devices give us information such as thermometers,water bottles and current meters for measuring thephysical and chemical properties of the water,dredges, corers, heat probes and cameras for studyingbottom sediments and bottom life. However, forcenturies the only evidence we had of marine life in thedeep sea was extremely scarce.The area we are discussing has rarely been visited.Diving using atmospheric suits (JIM) can only copeto around 450 meters currently. We need differentequipment to explore the depths we are discussing.In 1964 Alvin made the first successful scientific deepsea manned submersible dive on behalf of the WoodsHole Oceanographic Institute. Later updated versionshave been able to dive to 6,000 meters. Alvin was thefirst to discover hydrothermal vents and explore a smallsection of the mid oceanic ridge. We will return to thisenvironment later. For depths below this we rely onremote operated vehicles or ROVs. Cutting edge researchis being conducted using ROVs by Woods HoleOI and also Monterey bay Aquarium Research Institute.Man has even visited the lowest point. In January 1960Piccard and Walsh descended in the Trieste II(a bathyscaphe) to the deepest known point on Earth,the Mariana Trench at 10,915 meters.Despite the overall paucity of evidence and the factthat the vast majority of the seabed remains to beexplored we can discuss the deep water environmentin a dynamic way. New discoveries are being madefrequently in this field. Let us now look at the geologicalbasis of the deep sea environment.GEOLOGYThe Ocean lithosphere is approximately 100 km thick(therefore significantly thinner than the continentallithosphere) and this refers to the crust and the upperpart of the mantle. The lithosphere is composed mainlyof peridotite. The upper part of the lithosphere is thecrust which is made up mainly of lighter granitic rock.The oceanic crust is thinner and denser than the continentalcrust and made up mainly of basaltic rock.The entire lithosphere (oceanic and continental) sits ontop of the viscous lower layer called the asthenospherewhich forms part of the upper mantle. The lithosphereis composed of 7 major plates and6 minor ones.New oceanic lithosphere, or at least theoceanic crust, is formed atconstructive plate boundaries. Atsea floor spreading ridges
the asthenosphere wells up and cools and forms theoceanic floor on either side of the boundary.The Mid Atlantic Ridge is a classical example of this. Destructionof the oceanic lithosphere occurs in the subductionzones.The subducted plate descends into the hot mantle andis destroyed as it melts. The coast of Japan offers anexample of this. It should be noted that the environmentis dynamic over geological time as the processof subduction destroys the ocean floor. As new oceanfloor is formed it pushes the floor on either side awayand this may eventually enter a subduction zone andbe destroyed.It is possible to date the ocean crust as the plates moveapart and spread over the abyssal plain as they takeon the polarity of the Earth's magnetic field. This workwas described by Matthews and Vine. Also generallyspeaking the older the ocean crust the further awayfrom the spreading ridges it will be. The denser materialalso sinks further away from the surface of the sea.Given the age/depth relation the age of the oceancrust can also be estimated. The main "landform"features of the ocean basins are perhaps a Mid OceanRidge with an abyssal plain on either side of this ridge,constructive plate margins or destructive plate marginswith a deep ocean trench at the edges of the deepsea environment with pelagic sediments covering thefloor. Naturally there are many variations to this patternbut this brings us to a consideration of sedimentation.SEDIMENTS IN THE DEEP SEA ENVIRONMENTIn the true deep sea environment we are really onlyconcerned with deep sea sediments. However, thereare two main types of sediment, terragenous and bioclasticand less widespread types of sediment from volcanicand hydrothermal vent activity. Sediments canalso be classified as pelagic or deep sea sediments.If we look at terragenous sediments first, these are theresult of erosion from continental rocks. The materialeroded is deposited on the continental shelves by runoff or other physical actions and advances the continentalshelf seawards by deposition of sediments.Submarine fans may form e.g. the giant Ganges Fanand currents eventually move sediments off the continentalshelf and into the abyssal plain. Therefore thisbrief discussion of terragenous sediments is useful asthey do eventually enter our discussion remit.The ocean shifts the coarser material in turbidity currentsand there are occasional sudden movementse.g. 1929 Grand Banks in North America turbidity event.Bioclastic sediments are the result of biological activityand include the dead remains of pelagic plants andanimals that have sunk. Pelagic bioclastic sedimentsare also called oozes and may be composed ofcalcareous or silaceous materials. Calcareous ooze iscomposed of chalky remains of foraminifera andpteropods, and forms the deep ocean red clays.The silaceous material is derived from shells of radiolariansand diatoms and found mainly in tropicaland polar seas. The distribution of ooze reflects primaryproduction taking place near the surface. The thicknessof the sediments also reflects the age of the oceancrust with thickness increasing as we move away frommid ocean ridges for example.Volcanic ash from eruptions can also travel largedistances and end by being deposited on the oceanfloor, thus contributing to sediments. Finally around hydrothermalevents we have unique sediments with metalliferousmuds. It should also be noted that sedimentson the abyssal plains are not completely static as currents,earthquakes and tectonic activity can movethem. An understanding of sediments in the deep seaenvironment is vital when we discuss life in this region.DEEP WATER CONDITIONSDeep water is isolated from the effects of wind belowthe Ekman spirals which only influence down to 100 meters.However, changes at the surface can result in themovement of deep water with changes in temperature,density and salinity. Cold, dense water sinks andmoves very slowly along the depths of the ocean, requiringmany hundreds of years to move through anocean basin. There is no daily or seasonal variations effectivelyand this creates a very stable environment.Below 3,000 meters the area is isothermal effectively exceptfor areas around hydrothermal vents. The regionsunder discussion in this essay are mainly the Bathypelagicand Abyssalpelagic Zones so here the watersare dark, limited in nutrition, cold and at great pressure.For every 10m increase in depth pressure increases byone atmosphere so we are discussing pressuresof 200 to 600 atmospheres or morein our region since the average depthof the deep sea is 4,000 meters and insome cases goes to 11.000 metersin the trenches. A considerationof deep water conditions will be a vitalunderpinning to our section of life in the deepwater environment.LIFE IN THE DEEP SEA ENVIRONMENTDespite the apparent difficulties and challenges of lifein the deep sea environment organisms have managedto exploit these regions. We shall take a look atsome of the main groups of inhabitants, some of the difficultiesthey face and finally some of the adaptationsthey have evolved to cope with life in the deep sea.Firstly we should discuss briefly the presence of microorganismsin the deep sea. In fact most organisms inthe deep sea are microorganisms. These microbes areable to tolerate high pressure (barotolerant) and othersactually depend on high pressure (barophilic). In theMariana Trench there are extreme barophiles.
Most of these microbes are also psychrophilic i.e. theylike cold conditions. Bacteria at these levels have speciallyadapted enzymes and membranes. However,much research remains to be done in this area and resultscan sometimes be inconclusive or at least very surprising.For example in 1996 the Japanese submersibleKaiko scooped mud from the bottom of the ChallengerDeep in the Mariana Trench and when the many thousandsof organisms were examined none of them werebarophilic, halophilic or acidophilic but surprisingly alkaliphilesand even thermophiles so we should be carefulin making generalization in the hadal zone. However,other samples taken around the same time did result inthe successful isolation of some extreme barophiles relatedto the genera Shewanella, Moritella and Colwellia.However, as we shall see not only microbes livein these zones.ANIMALS OF THE DEEP SEA ENVIRONMENTThe deep sea is home to most phyla of animals butchanges in abundance of different animals with increasingdepth. Research in the Kurile-Kamchatkashows that sponges are dominant down to 2000 metersbut we are focussed on the deeper regions. Sea cucumbersare the commonest animals found below4000 meters and polychete worms make up a largepercentage of benthic or bottom dwelling animals. Seacucumbers and seapigs (Holothuroidea) are often themost common animal in deep dredges. Seapigs havebeen caught at 10,000 meters deep in the KermadecTench. These feed by ploughing the deep sea mudand digest bacteria and organics. Some can swimabove the ooze though.Starfish have been found down to 7,000 meters. Brittleand basket stars (Ophiuroidea) are found. Small crustaceanssuch as amphipods and isopods, as well asmolluscs (such as clams) and sea anemones havebeen found at great depths. There were relatively fewcrabs and fish found at these depths but this may havebeen more to do with the sampling methods used. Onthe ocean bed deposit feeders predominate with seacucumbers and worms at the deepest levels. There arein fact many species of smaller infaunal animal here.Some estimates reckon close to a million differentspecies of benthic invertebrates in the deep sea sediments.This shows why our above consideration of sedimentsis so fundamental to a discussion of the deepocean environment. However, the number of individualsanimals decreases from the surface to the deephadal trenches.We stated that there were relatively few crabs and fishfound at great depth but they are represented. Lets ustake three species as examples. Firstly a fish that is oftenignored because of its more spectacular rivals the - RattailFish or Grenadier fish. This is termed benthopelagicor demersal because they swim justabove the bottom. This relative of codis in fact the most common fish found in the abyssaldepths. The deepest Rattail observed lives down to 6500meters. These belong to the family Macrouidae andhave large heads and tapering bodies and feed byboth hunting and scavenging. They are being fishedcommercially. Secondly we have the Hatchet fish(Argyropelecus olfersi). They are camouflaged with silverybodies, a flattened body for reduced silhouetteand photophores that match the downwelling light sothey are difficult to see. They search the waters abovewith their tubular eyes. We shall consider these adaptationsin the next section. Thirdly we have the Lantern fish(Ceactoscopelus warmingii), which are about 5 to 15centimeters long, have numerous photophores and migratedaily upwards to feed. We have space here onlyto discuss a few of the many species in the deep sea environment.Other species include sea urchins, crinoids,Tripod fish, gulper eels, sponges and seapens. Some arepermanent dwellers in this environment such as deepsea cucumbers and others are visitors to our region suchas the large Greenland shark (Somniosus microcephalus)down to 2,200 meters and the six gilled Hexanchus downto 2,500 meters but all have some adaptations to copewith the deep sea environment. These and other adaptationsto life in the deep sea environment will now bediscussed in more detail.DEEP SEA CHALLENGES TO ANIMALSAND THEIR ADAPTATIONSLets us select five main categories to discuss as follows:adaptations to pressure, temperature, food availability,lack of light, and reproduction.Pressure and temperatureAnimals adapt to pressure in a variety of ways e.g.sperm whales have lungs that can compress to 1% oftheir normal volume, angler fish have reduced skeletonsand other fish have reduced muscle mass. Sea cucumbershave bodies largely composed of water andothers have proteins and enzymes adapted to work atpressure. Sharks have oily livers instead of swim bladdersto cope with extremes of pressure. It is also difficultto produce calcium carbonate shells due to pressureand temperature issues. As pressure increases and temperaturedecreases calcium carbonate becomes solublemaking it difficult for creatures to secrete shells.The depth when no calcium carbonate present iscalled the carbonate compensation depth or CCD.Today the CCD in the Pacific ranges from 4,200 metersto 4,500 meters deep and in the Atlantic 5,000 metersdeep. Many species have dispensed with shell formationbelow the carbonate compensation depth. Inthese ways we see that there are physiological andchemical adaptations to cope with increased pressure.Secondly we have a brief discussion of temperature.The deep sea is largely isothermal with very stable temperaturesprevailing that need few adaptations.Hydrothermal vents are an exception to this rule andwe will discuss these in more detail later in the thesis.
Food availabilityAs far as food availability is concerned there are manyadaptations animals use to cope ranging from predatoryand scavenging behavior, opportunistic feedingon whale carcasses to vertical migration strategies. Letus look at these in more detail now: Basically food availabilitydecreases with depth as does species diversity.The supply of food to the deep sea depends on primaryproduction in the photic zone (except for hydrothermalvent areas). However, it has beenestimated that just 2% of phytoplankton sink to the bottomas they are mainly consumed above or on the waydown. Since food is relatively scarce the marine organismshave a number of ways of coping.We can loosely categorize these as1) Energy conservation adaptations e.g. slow movements,slow metabolisms, and some fish with relativelylow muscle mass compared to fish in shallowerseas.2) Related to energy conservation some fish are ambushpredators e.g. deep sea Angler fish, using bioluminescentlures.3) Dwarfism and gigantism are methods of coping withfood availability e.g. tiny nematode worms at oneextreme and large amphipods (up to 28cm) at theother.4) Physiological adaptations also include distendedstomachs and hinged jaws in some species to copewith the rare chances of feeding e.g. angler fish andgulper eels but even bivalves in the deep oceanhave been found to have longer guts to take full advantageof food availability.5) Related to this opportunistic feeding but perhaps ina class of its own we have the animals adapted tofeed on dead whales. These are very important andprovide many year's food supply to an area of theocean floor in one moment. 43 species have beenfound on one whale carcass e.g. sharks, hagfish,bone eating zombie worms, snails, limpets, clamsand anaerobic bacteria. Since there are many similaritieswith organisms found round hydrothermalvents these carcasses may have acted as steppingstones from vent to vent.6) Deposit feeders. Since the deep sea floor is dominatedby loosely compacted biogenic ooze it isdominated by deposit feeders like the deep sea cucumber(Scotoplanes). Deposit feeders may makeup to 80% of the species on the sea floor. Most of thesea bed is covered in soft clays or mud like oozesmade of skeletons of tiny sea animals and fecal material.The ooze in the abyss can reach several hundredmeters thick. Some animals walking along thebottom have very long legs to avoid stirring the mudup e.g. deep sea spider. These are not true spidersbut belong to the pycnogonids. Other species growanchored to the sea bed and have long stems tokeep feeding structures clear of the ooze.7) Vertical migration. Some fish move upwards to feedand have replaced swim bladders with fatty depositsin order to cope with the vast differences inpressure. The Rattail fish mentioned above is a goodexample of this travelling up to 1,700 meters upwardsin a night to feed. This is just a brief cross sectionof the ways in which animals cope with limitedfood supplies.Lack of lightLack of light perhaps creates some of the mostinteresting adaptations. Eyes of fish in thedeep sea tend to be generally larger than theircounterparts above, although below 2000 meters eyesagain grow smaller or are absent. Eyes contain a higherdensity of rods in the retina or tubular eyes are commone.g. hatchet fish. Where eyes are useless in thetotal darkness other methods have developed to sensethe environment. Lateral lines are well developed tosense vibrations and antennae may also be used e.g.in hairy angler fish. Bioluminescence is another adaptionwith 60 to 70% of deep water animals possessingthis ability. Organs called photophores, sometimesusing bacteria as a light source are found in many fishe.g. lantern fish. Simple photophores either producelight or retain light producing bacteria such as Vibrio orPhotobacterium in a symbiotic relationship. Since bacteriaproduce light continuously the host animals developways to control emissions e.g. reflective layers,flaps and lenses. Squid have the most spectacular abilitiesin this area. Bioluminescence can be used as a lurefor food or for defence. Areas of photophores in the anglerfish are for lures. The hatchet fish uses light for camouflageand the squids for defense as a burst ofunexpected light can distract an attacker.Since the dominant sense in the deep sea is hearing weshould discuss this in a little more detail. Many invertebratesdetect sound by cilia. Fish detect by sensoryhairs in the otolith organ in the inner ear. Lateral line systemsalso enable fish to detect sound vibrations, movementsof prey and fish in schools and changes in oceancurrents. Animals around the hydrothermal vent systemsmay rely on this to avoid the vents themselves butwe will return to a discussion of vents later. When weconsider vision there are also a variety of systems in use.There are relatively simple systems such as eyespots e.g.polychete worms to the spherical lens systems of fishwhich allow them to have light perception beyond thecapabilities of man as we have mentioned above.Next we should consider the sense of orientation in marineanimals. Several species can detect the pull ofgravity with organs known as statocysts. In vertebratesthe semicircular canal in the ear performs this function.Next we come to chemoreception covering the sensesof taste and smell. The sense of smell (olfaction) is extremelywell developed in sharks. and these do venturedown into the regions we are discussing. Electroreceptionis another sense used by sharks and some otherpredatory fish who posses electrosensory organs.
In sharks these are known as ampulla of Lorenzini. Finallythere is the sense of magnetoreception and magnetitecrystals have been found in fish that may enable themto navigate over long distances. Much research remainsto be done in this area it seems, particularly in relationto deep sea species.ReproductionFinally we have adaptations in reproduction in thedeep sea with eggs with large yolks to combat lack offood, long lived species with slow sexual maturity mayalso help in this area. The relative difficulty of finding isolatedmates may also have led to high degrees of hermaphroditicbehavior. For example tripod fish haveboth male and female sex organs. The tripod is unusualin that male and female organs may reach maturity atthe same time thus allowing the fish to fertilize its owneggs. Perhaps it is so sparsely distributed that one fishmay not find a mate at the right time. The famousadaptation of the tiny parasitic male in angler fish is anotheradaptation to this isolation. The tiny male clampsonto the female and is even partially absorbed by herthus ensuring a source of fertilization at the right time.Deep sea species tend to be slow growing, late maturingand low in reproductive capacity. Many deepwater fish species live 30 years or more and the orangeroughy can live up to 150 years. These are just some ofthe adaptations to the deep sea. If we look in more detailsat certain unique communities in the deep sea environmentwe can observe other adaptationsA NOTE ON HYDROTHERMAL VENTS AND HYDROCAR-BON SEEPSHydrothermal vents systems are one such unique community.These have been of interest really since theAlvin discoveries in 1977 in the Galapagos Rift Zone. Hydrothermalvent systems develop at depths of severalkilometers in the oceans in mid ocean spreading centerswhere there is hot upwelling lava. Sea water percolatesand is vented back at hot temperatures, full ofminerals, as either warm seeps, black or white "smokers".White smokers are only slightly cooler than blacksmokers and because they are rich in zinc have a whitetinge. Animals here must have a unique set of adaptations.Since they are far from the photic zone the inhabitantsrely on bacteria such as Beggiatoa toproduce food from chemosynthesis of caustic compoundssuch as hydrogen sulphide. These bacteriasometimes form mats near the vents and are in turngrazed upon by limpets and gastropod molluscs. Othercommunities of bacteria live in symbiosis with the gianttube worms (Riftia pachyptila) for example. Riftia cangrow up to 1.5 meters long and have unique adaptationsto the deep sea environment in that they cancarry both oxygen and hydrogen sulphide in theirblood to supply the bacteria. The clams (Calyptogenamagnifica) near the vent systems have similar techniques.So far scientists have discovered over 236species around the vent systems. 223 of these werenew to science and many of them endemic to ventsystems. More vent systems have now been explorede.g. Hole to Hell and Hanging Gardens on the East PacificRise, the Snake Pit on the Mid Atlantic Ridge andthe Rose Garden in the Galapagos Rift Zone. Howthese species developed and spread from system tosystem is a matter of interest and one theory suggeststhey may use whale carcasses as stepping stones.There are also many theories about how life may haveoriginated around these vents and in fact these areasmay even have been where photosynthesis first developedas there is a faint haze around these vents. Thereare animals here with extreme UV sensitivity such ashuge shrimp with massive numbers of photoreceptorsin their eyes.The vent systems are highly dynamic andunstable environments but they do support uniquelyadapted communities of marine life which are an importantpart of the discussion the deep seaenvironmentIn addition to this perhaps we should also consideranother unique deep sea environmentnamely Hydrocarbon seeps. These fall within our studyas some of these steeps are more than 2000 metersdown. Marine hydrocarbon seeps are cold (as distinguishedfrom hydrothermal vent activity) and have twomajor sources, biogenic (bacterial production of gases)and petrogenic i.e. relates to subsurface petroleumreservoirs that leak to the surface. Some seep gassesarise from CH4 hydrate dissociation, a water ice that isstable at great depths and low temperatures. Hydrocarbonseepage produces asphalt volcanism, brinepools, gas hydrates and authigenic carbonates. Hydrocarbonseepages are a feature in the Gulf of Mexicoand we know from research done at theChapopote site what minerals are involved. Accordingto one study by the University of Texas communities ofchemosynthetic fauna that depend on seeping oil andgas have been found at over 45 sites in the Gulf of Mexicoso far down to the 2200 meters below sea level. Thedominant fauna consist of species within four groups:tube worms, seep mussels, epibenthic clams, and infaunalclams. The development of these communities isclosely linked to the geological and geochemicalprocesses of seepage. Temperatures varied between5 and 9 degrees Celsius. The full consequences and importanceof both hydrothermal vents and hydrocarbonseepages has perhaps not yet been sufficiently realizedor fully researched but these are fascinating and vitalparts of the deep sea environment.CONCLUSIONWe have briefly discussed the geology, sedimentation,water mass and life forms and their adaptations in thedeep sea environment. Until relatively recently the relevanceof this environment to man was little studiedand perhaps not regarded as particularly relevant forthe future of man on Earth. In this summary we shouldtouch upon seven key areas we have selected that link
the deep sea environment with man's future. The firsttopic regards biodiversity. Of the estimated 500,000 to10 million species living in the deep sea, the majority areyet to be discovered. There could be no clearer illustrationof the value of the world's deep sea environments.Approximately 98% of the world's species live inor just above the floor of the sea. (This includes someareas strictly outside our remit). Many of these speciesare related to seamounts for example. However, theunique environments harbor a breathtaking array ofspecies with high rates of endemism. Each unsampledtrench, vent and seep is a potential source of numerousundiscovered species. In addition two thirds of allknown coral species live in waters that are deep, darkand cold, down to over 3000 meters deep, which belongsto our area under discussion. Some of these coldwater corals are 5-8,000 years old or more and over 35meters high. These and other habitat forming organismsprovide protection from currents and predators, nurseriesfor young fish, and feeding, breeding and spawningareas for hundreds of thousands of species andtherefore are a critical feature of the Earths biodiversity.Secondly we should consider the feeding of the world'sever expanding population. Commercially importantdeep water fish and crustacean populations found inthe high seas include crabs, shrimp, cod, Pacific cod,orange roughy, armorhead, grenadier, Patagoniantoothfish (also known as Chilean sea bass), jacks, snappers,porgies, sharks, groupers, rockfish, Atka mackereland sablefish.Thirdly, we have the medical uses and implications ofthe deep sea environment. For example Gorgoniancorals produce antibiotics. Compounds found in certaindeep sea sponges are powerful immunosuppressiveand anti-cancer agents. In addition some coralscontain the pain killing compounds known aspseudopterosians. Seafans contain high concentrationsof posaglandins used to treat asthma and heartdisease.Our fourth point concerns energy and mineral resources.The deep sea environment harbors unexploreddeposits of oil, gas, and many minerals. Seismic surveyshave so far only detected a fraction of available reserves.A resource hungry world will need to exploitthese reserves at some point in its future and the morewe know about the deep sea environment the betterwe can use these reserves and hopefully lessen the impact.Fifthly, we need to consider the relationship of thedeep sea environment to our immediate environment.At first it appears there is little direct connection betweenthe abyssal depths and our own world. However,according to one study at the University of Indianadeep sea hydrothermal vents may play an importantpart in regulating the temperature and chemical balanceof the oceans. Before the discovery of hydrothermalvents scientists believed that the chemicalbalance of the oceans was determined primarily by runoff from the continents. Now hydrothermal vent ( andhydrocarbon seep) influence is seen as important. Infact the university describes the hydrothermal circulationsystems with wide ranging effects. Effects of pollutionand deep sea circulation systems are vital to anunderstanding of the Earth's environment.Sixthly, we need to consider the purely scientific importanceof the deep sea environments. It is a treasurehouse of untapped discovery and resource. For exampleancient deep sea corals provide valuable recordsof climate conditions that may assist our understandingof global climate change. Studies of this environmentare making contributions to almost every branch of sciencefrom climatology to the search for the origins oflife itself and in fact the deep sea is often seen as anextreme environment comparable to conditions prevailingon other planets.Finally we will always be aware of the commercial attractionsof the deep. These commercial considerationsrange from the exploitation of hydrocarbon reserves,mineral reserves, deep sea fishing to the deep seacommunities, particularly of corals and sponges whichare untapped sources of natural products with enormouspotential as pharmaceuticals (mentionedabove) enzymes, pesticides and cosmetics. By harvestingthe deep sea environment responsibly we cancontribute to a more balanced and prosperous worldbut by overexploiting we can cause global chaos. Forall these reasons an understanding of the deep sea environmentis pivotal to mankind's future.SOURCESDeep Sea Conservation CoalitionIndiana University studies on hydrothermal circulationTexas University studies on hydrocarbon seepsMonterey Bay Aquarium Research InstituteNew ScientistSimon HardingChairman of COBERON - CHRONOS GROUP