Dr. Rosenblatt is a board-certified anesthesiologist (retired), having been in both academia and private practice, and ls a member of the Naval Submarine League.
The deployment of nuclear attack submarines into the Persian Gulf constitutes an important aspect of the U.S. Navy’s Maritime Strategy as it relates to this vital area of the world. The physical attributes of the Persian Gulf-its shallowness, numerous navigation hazards and poor acoustic enviroment-all contribute to hinder underwater operations. An ancillary development, recently noted, may further complicate the ability of submarines to operate within the Persian Gulf on a routine basis two double-bottom commercial oil tankers, relatively new, were found to have sustained extensive corrosion soon after exposure to a marine microbial in the Persian Gulf. 1 A similar pattern of extensive corrosion appeared in a U.S. Navy nuclear submarine upon completion of an extended deployment to this region. An Archaea microbial is most likely the presumed biological entity responsible for these unusual presentations of fulminate marine corrosion.
Archaea are the microorganisms that live adjacent to hydrothermal vents (black smokers) at the mid-ocean rifts found during underwater explorations by deep diving submersibles. 2 These microorganisms are distinctly different from either bacteria or eukarya (cellular organisms that possess intracellular structures) and have been classified as an entirely new domain. 3 Their discovery ranks as one of the most important recent advances in microbiology. Archaea are now known to be distributed world-wide existing in soil, subterranean deposits and marine environments. These microbials can survive under some rather extraordinary conditions which otherwise were thought to be incompatible with life. Archaea have the unusual ability to utilize sulfur or its derivatives as their principal source of biochemical energy, doing so in a reductive, anerobic, non-photosynthetic environment and are seemingly insensitive to high ambient pressure or temperature.
The biochemistry of Archaea is thus singularly unique. Scientists believe that Arcbaea play a significant role in the deposition of metal ores and biotransformation of petrochemicals. It has been postulated that. given the age of the earth and enzymatic activity of the estimated Arcbaea biomass, these microorganisms have biotransformed at one time or another the entire mass of the minerals found in the crust of the earth. 7 Their biochemical dexterity and appetite for petrochemicals are no less impressive. Following the massive oil spills that occurred in Alaska and elsewhere, the rapidity of petrochemical bioremediation has surprised the scientific community. The full extent of the contribution made by these microbials to geologic processes remains to be determined.
Archaea, by similar means, are seemingly able to corrode the hull and other components of ship construction. The American Bureau of Shipping (ABS) reported recently that a fulminate form of marine corrosion had taken place in the voids of the two previously mentioned double-bottom oil tankers (an anaerobic environment contaminated by petrochemical spillage). 1 The pattern of corrosion observed in the tankers was unusual. The worst damage was sustained by high-tensile and stainless steels, which corroded in layers rather than through more common surface pitting. Alarmingly, protective coatings proved ineffectual bactericidal chemicals and algicides used to clean the bilge only accelerated the rapidity of marine corrosion. This disturbing development has prompted the ABS to form a special task force to investigate this problem and make recommendations for corrective action. The situation has assumed paramount importance with reports of double-bottom oil tankers discharging contaminated bilge contents laden with foreign biological matter into harbors throughout the world.
While the two episodes of fulminate marine corrosion have involved to date double-bottom oil tankers, it is not unexpected that submarines with their analogous structure, use of high-grade steels and persistent submergence should be vulnerable to a similar pattern of damage by a sulfur-digesting Archaean. Recent events appear to confirm this supposition. The United States and Iranian navies have conducted prolonged submarine operations in the Persian Gulf; both navies have incurred assorted damage from biologically-induced marine corrosion in their respective submarines.
One U.S. submarine returned from an extended submerged deployment to the Persian Gulf with a highly unusual and extensive pattern of marine corrosion; this despite a complete refit prior to the deployment. All seals OD the propeller shaft were compromised, the packing on the periscopes were leaking seawater into the control room, and the crew was forced to decant and recycle hydraulic fluid that had been contaminated with seawater on the transit back to the submarine’s homeport.
The magnitude of the corrosion found OD the submarine while it was in drydock upon its return was startling. The hull and propeller had visible corrosion that resembled the marine equivalent of smallpox. The hull had patches of corrosion that appeared to have flaked off layers rather than showing the normal randomized pitting, similar to what had been observed previously in the double-bottom oil tankers. Neither the fiberglass sonar dome nor the silicate anechoic tiles had demonstrable damage. The zinc galvanic plates located on the dorsum of the submarine forward of the propeller likewise appeared unaffected and void of overt electrolysis. Evidence of corrosive damage was likewise found within the submarine. Black rubber fittings, exposed to the contaminated hydraulic fluid, showed an advanced state of decay; when handled the rubber disintegrated into a granular powder. In sharp contrast, Tigon ™ tubing in direct contact with the contaminated hydraulic fluid and the corroded rubber washers was intact. These findings were subsequently reported in an abstract written by the author and Captain J.H. Patton, Jr., USN(Ret.) accepted for presentation at the 1996 NATO Undersea Defense Technology Conference.
Inspection of the submarine further disclosed additional confirmation of marine corrosion by a sulfur-digesting Archaea microbial. A number of barnacles were recovered from free-flooding spaces within the hull. Dissection of the barnacles revealed a prominent black growth ring midpoint in the cross-section of the shells, consistent with the time spent by the submarine in the Persian Gulf during its deployment. A black inclusion body was encapsulated within the barnacle which smelled and tasted of sulfur. A similar finding has been noted in tubular worms and clams that live next to deepsea hydrothermal vents. The Archaea colonies in these environments subsist by means of chemosynthesis on a diet of sulfur emitted from the vent. Sulfur and its derivatives, however, are toxic to the non-Archaean organisms that comprise the vent community but which depend, in tum, on the Archaea as their basic source of nutrition. The sulfur intolerant lifeforms resolve this dilemma by segregating the sulfur residues into a sac-like organelle contained within their bodies.
A second indication of Archaea infestation in the bull of the submarine was found as well. Located on the intakes of the secondary propulsion unit was a deposit of greyish-white ash several centimeters thick that was covered by a proteinaceous layer. The material bad a putrid odor characteristic of hydrogen sulfide. Similar findings of a proteinaceous mat and cellular debris with sulfide residues have been reported by oceanographers investigating underwater hydrothermal vents and the associated Archaea colonies.
The unusual biological properties of the Persian Gulf did not go unnoticed by the submarine’s crew. After the first month’s deployment in the operational area, the submarine was covered by a several-centimeters-thick layer of marine growth adherent to the outer hull that likewise had a most noxious odor associated with it. The marine growth on the submarine’s hull was so extensive that it had a profound impact on the boat’s performance despite repeated attempts at removal: a loss of six knots of speed was measured during the return transit.
Analogous difficulties have been encountered by the Iranian Navy with the operation of their Russian built Kilo class submarines based at Bandar Abbas. Jane’s Defense Weekly has published several accounts that indicate the Iranian Navy has experienced a marked reduction in the operational readiness of their submarine force due to extensive corrosion from marine growth fouling hulls and clogging multiple valves. 10 11 Maintenance problems were previously reported with the submarine batteries sold by Russia and, more recently. India for the Kilo submarines. Although it is conjectural, contamination of the bilge water by Archaea microbials and subsequent spread within the battery compartment could result in premature failure of the rubber casings of the lead-acid batteries. The presence of Archaea in the waters of the Persian Gulf is not unanticipated, given the availability of sites favorable for their growth.
Archaea are organisms commonly found in the micro-ecologic environment of hydrothermal and volcanic vents. The Middle East and, in particular, the Persian Gulf contain numerous indications of geologic and volcanic activity. An extensive deepsea rift in the Red Sea consists of a linear expanse of volcanic vents spewing 350°C water, hydrogen sulfide and dissolved minerals. 12 13 This rift in the earth’s crust extends around the eastern border of the Arabian Peninsula and then curves in a northerly direction. It proceeds into Oman whereupon it crosses the Strait of Hormuz. There it encounters the Makran subduction zone, an area where the Arabian tectonic plate impacts and slides underneath the Iranian segment of the Euro-Asian continental plate. The northern border
of the fault is demarcated by a volcanic arc in S.E. Iran some 300 km. inland.
The Persian Gulf is a marginal sea that overlies the zone where the two respective tectonic plates are colliding. The Zagros Mountains, which flank the northern border of the Persian Gulf, arose as a result. Volcanic activity and hydrothermal sites are often found at these geologic junctures. In Oman there exists an enormous geological formation, termed the Omani ophiolites, which is the remnant of volcanic activity. The notable absence of geothermal surface activity in either northern Oman or southeastern Iran can be attributed to the lack of sufficient groundwater in the surrounding areas. The analogous underwater sites along the fault line, nevertheless, should be geothermally active despite the lack of surface manifestations, and thereby provide the necessary habitat for Archaea to thrive.
Other geological formations in the proximity of the Strait of Honnuz substantiate the existence of past and current hydrothermal sites in this area. In northern Oman pillow lava is found, indicative of underwater volcanic eruptions. Various mineral deposits, formed by seafloor hot springs, are likewise found throughout the region. The presence of underwater geothermal sites is further indicated by measurements that show increased water and crust temperatures for the Strait of Hormuz and surrounding area in comparison to the average water temperatures found throughout the Persian Gulf; this despite the greater depth of the sea in the locality Lastly, the Persian Gulf has some of the highest biomass densities found to date anywhere in the world’s oceans. One of the remarkable attributes of Archaea colonies living next to hydrothermal vents is their unusually high biomass densities, far more than the comparable biomass densities of mid-ocean seawater.
It is the conclusion of the author that the submarine in question was damaged by a biological casualty. Arcbaea, a microorganism known to inhabit underwater geothermal sites, such as those that presumably exist in the vicinity of the Strait of Hormuz. Furthermore, Archaea microbials seem to have the unique propensity to produce an accelerated, fulminate pattern of marine corrosion. Until detailed oceanographic analysis of the Persian Gulf is undertaken, these observations cannot be confirmed with absolute certainty. With the political situation of the Persian Gulf being what it is and the current acrimonious state of relations that exists between the United States and Iran, it is doubtful that such definitive research will be feasible in the foreseeable future.
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