Grow at o °c. Optimum temperature 15 °c or lower. Maximum 20 °c Habitats :-

6. Extremophiles are microorganisms which have adapted so that they can survive and even thrive in conditions that are normally fatal to most life-forms. For example, some species have been found in the following extreme environments: Temperature: as high as 130 °C (266 °F),as low as −17 °C (1 °F) Acidity/alkalinity: less than pH 0, up to pH 11.5 Salinity: up to saturation Pressure: up to 1,000-2,000 atm, down to 0 atm (e.g. vacuum of space) Radiation: up to 5kGy Extremophiles are significant in different ways. They extend terrestrial life into much of the Earth's hydrosphere, crust and atmosphere, their specific evolutionary adaptation mechanisms to their extreme environment can be exploited in bio-technology, and their very existence under such extreme conditions increases the potential for extraterrestrial life.

8. Grow at o °c. • Optimum temperature 15 °c or • lower. • Maximum 20 °c • Habitats :- • Isolated Artic and Antartic habitats. • (90% of the ocean is 5°C or colder) • Examples :-  • Arthrobacter sp.,  • Psychrobacter sp.   • PSYCHROTROPHS: • Legionella.

11. Psychrophiles

13. Halophiles can be found anywhere with a concentration of salt five times greater than the salt concentration of the ocean, • Great Salt Lake (Utah)  • Owens Lake (California) • Dead Sea, • Evaporation Ponds. Halobacterium sp. strain NRC-1, each cell about 5 μm in length.

14. Adapted extreme hypertonic environment. • Grow optimally,Presents of Nacl or other salts. • Sea water contain 35% mixes with fresh water- nearly 0%. • E.x: • Halobacterium. • Halococcus Halobacterium- Halococcus. Phylum: Extreme 

15. Halobacterium Halobacterium sp. strain NRC-1, each cell about 5 μm in length. Scientific classification Domain: Archaea Kingdom: Euryarchaeota Phylum: Euryarchaeota Class: Halobacteria Order: Halobacteriales Family: Halobacteriaceae Genus: Halobacterium Binomial name HalobacteriumElazari-Volcani 1957 Species • H. jilantaiense • H. noricense • H. salinarum • H. piscisalsi In taxonomy, Halobacterium is a genus of the Halobacteriaceae

16. Halococcus Scientific classification Domain: Archaea Kingdom: Euryarchaeota Phylum: Euryarchaeota Class: Halobacteria Order: Halobacteriales Family: Halobacteriaceae Genus: Halococcus Binomial name Halococcus Schoop 1935 Species • H. dombrowskii • H. hamelinii • H. morrhuae • H. qingdaogense • H. saccharolyticus • H. salifodinae • H. thailandensis Halococcus is a genus of the Halobacteriaceae.

17. Adapted completely hypertonic saline condition • Require high level Nacl • Salinity: • It is remarkably constant throughout the deep sea. • Some minor differences in salinity, but none that are ecologically significant, except in the Mediterranean & Red seas.

19.  Below the thermocline, the water mass of the deep ocean is cold and far more homogeneous. • temperature of the epipelagic zone, is above 20°C. • based on the epipelagic, it drops over several hundred meters to 5 or 6°C at 1,000 meters. • Affects growth of microbs • High temperature damages microbes by denaturing enzymes ,transport carriers and other proteins • Microorganisms can placed in 5 clanes based on temperature ranges

21. THERMOPHILES: • Grow at 55 ° c or higher. • Minimum -45 ° c . • Optimum-55 c to 65 °c. • Present in a planet’s surface from which • Geothermally “Heated Water Issues”. • Commonly found near volcanically active places, • ocean basins & hotspots. • It forms some features in under the sea called • “Black Smokers”. A colony of thermophiles in the outflow of Mickey Hot Springs,  Oregon, the water temperature is approximately 60°C.

22. HYPERTHERMOPHILES: • Grow at 90°c. • Maxima above 100°c. • Don ‘t grow below 55 °c.Microorganisms in deep-sea hydrothermal plumes:- • Hydrothermal vents vary considerably, from relatively low-temperature (<25 °C) fluid discharges to the spectacular high-temperature (~350 °C) • black smokers1–3. • The high-temperature vents give rise to buoyant plumes which can be detected hundreds of kilometres away from ridge crests4,5.

23. BLACK SMOKERS: It found on sea bed, typically in the abyssal & hadal zones. In the immediate vicinity of hydrothermal vents, chemoautotrophic bacteria are present in vent fluids, attached to rock surfaces9,10, and as endosymbionts in certain macro fauna11

24. WHITE SMOKERS: • Contain barium, calcium & silicon. • Vent organism depend on chemosynthetic bacteria for food. • It contains huge number of bacteria.

26. PRESSURE: Prokaryotes live in deep sea. Hydrostatic pressure -600 to 1100 atm and temperature -2 to 3 °c. Greatest environmental factors acting on deep sea organism.  it increases 1 atmosphere (atm) for each 10 m in depth. In deep sea is under pressures between 200 and 600 atm, the range of pressure is from 20 to 1,000 atm. Microbes live on land or surface water – 1atm Can play a major role in nutrient recycling in deep sea. E.g : Photobacterium , Shewanella.

28. Existing below the “thermocline” & above seabed. • It is very icy and dark at the bottom. • Sunlight can’t reach there but most of the deep sea produced light that can be seen easily in dark • deep sea or deep layer in the ocean existing below the thermoline and allow the seabed depth of 1000 or more • Most organisms falling organic matter produced in the photic zone

31. Definition: • Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. • Nitrification in the marine environment: • In the marine environment, nitrogen is often the limiting nutrient • The nitrification step of the cycle is of particular interest in the ocean because it creates nitrate, the primary form of nitrogen responsible for “new” production. • Furthermore, as the ocean becomes enriched in anthropogenic CO2, the resulting decrease in pH could lead to decreasing rates of nitrification.

32. Nitrification as stated above is formally a two-step process. First Step : ammonia is oxidized to nitrite, Nitrification is a process of nitrogen compound oxidation : NH3 + 11/2 O2 + Nitrosomonas -------→ NO2- + H2O + H+ NO2- + 1/2O2 + Nitrobacter ------------→ NO3- NH3 + O2 -----------------------------------→ NO2− + 3H+ + 2e− NO2− + H2O ------------------------------→ NO3− + 2H+ + 2e−

33. Second Step : nitrite is oxidized to nitrate. Different microbes are responsible for each step in the marine environment. Several groups of ammonia oxidizing bacteria (AOB) are known in the marine environment Example::- Bacteria :- Nitrosomonas,  Nitrospira, and  Nitrosococcus. Nitrospina and  Nitrobacter are known to carry out this step in the ocean. All contain the functional gene ammonia monooxygenase (AMO) which, as its name implies, is responsible for the oxidation of ammonia.

35. Definition:- Denitrification is a microbially facilitated process of nitrate reduction that may ultimately produce molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products. Measurement:- denitrification rates were measured in sediment cores from a MARINE of the Chesapeake Bay using high precision membrane inlet mass spectrometry. Denitrification was independent of salinity over the range of 1-13 ppt and directly dependent on nitrate concentration over the range of 0-200 µM in the overlying water. Denitrification was observed when the water colunm nitrate concentration was <1 µM, indicating that nitrification in the sediments was occurring. Moreover, the enhanced rate under nitrate enrichment was either stable or changed slowly over periods of days.

36. 4KNO3+502----------2K2 O + 2N2 • molecules of oxygen are consumed for each molecule of nitrogen • evolved, but the amount of oxygen liberated at each stage • is different: • Nitrate to nitrite. • 2KNO3+ 02 - --- + 2KNO2 • (ii) Nitrite to hyponitrite. • 2KNO2+ 02 -- -- +2 KN202. • (iii) Hyponitrite to nitrogen. • 2K2N202 + 02 - -- + 2K2O + 2N2

38. Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. • Organisms capable of producing methane have been identified only from the kingdom Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. • The production of methane is an important and widespread form of microbial metabolism. • In most environments, it is the final step in the decomposition of biomass.

39. Strains of methanogens • Methanobacterium bryantii • Methanobacterium formicum • Methanobrevibacter arboriphilicus • Methanobrevibacter gottschalkii • Methanobrevibacter ruminantium • Methanobrevibacter smithii • Methanocalculus chunghsingensis • Methanococcoides burtonii • Methanococcus aeolicus • Methanococcus deltae • Methanococcus jannaschii • Methanococcus maripaludis • Methanococcus vannielii • Methanocorpusculum labreanum • Methanoculleus bourgensis (Methanogenium olentangyi & Methanogenium bourgense) • Methanoculleus marisnigri • Methanofollis liminatans • Methanogenium cariaci • Methanogenium frigidum • Methanogenium organophilum • Methanogenium wolfei • Methanomicrobium mobile • Methanopyrus kandleri • Methanoregula boonei • Methanosaeta concilii • Methanosaeta thermophila • Methanosarcina acetivorans • Methanosarcina barkeri • Methanosarcina mazei • Methanosphaera stadtmanae • Methanospirillium hungatei • Methanothermobacter defluvii (Methanobacterium defluvii) • Methanothermobacter thermautotrophicus (Methanobacterium thermoautotrophicum) • Methanothermobacter thermoflexus (Methanobacterium thermoflexum) • Methanothermobacter wolfei (Methanobacterium wolfei) • Methanothrix sochngenii

41. Ammonification: When a marine plant or animal dies, or an animal expels waste, the initial form of nitrogen is organic. Bacteria, or fungi in some cases, convert the organic nitrogen within the remains back into ammonium (NH4+), a process called ammonification or mineralization. Enzymes Involved: GS: Gln Synthetase (Cytosolic & PLastid) GOGAT: Glu 2-oxoglutarate aminotransferase (Ferredoxin & NADH dependent) GDH: Glu Dehydrogenase: Minor Role in ammonium assimilation. Important in amino acid catabolism.

43. Sulfur cycle • Sulfur is one of the constituents of many proteins, vitamins and hormones. It recycles as in other biogeochemical cycles. • The essential steps of the sulfur cycle are: • Mineralization of organic sulfur to the inorganic form, hydrogen sulfide: (H2S). • Oxidation of sulfide and elemental sulfur (S) and related compounds to sulfate. • Reduction of sulfate to sulfide. • Microbial immobilization of the sulfur compounds and subsequent incorporation into the organic form of sulfur.

48. Dimethylsulfoniopropionate (DMSP):-  • Formula:- •  (CH3)2S+CH2CH2COO−. • This zwitterionic metabolitefound :- • Marine Phytoplankton,  • Seaweeds, • Species Of Terrestrial And • Aquatic Vascular Plants. • Functions:- • Osmolyte • Physiological and • environmental roles. • Degradation:- • DMSP is broken down by marine microbes to form two major volatile sulfur products. • Ismethanethiol (CH3SH), • Dimethyl Sulfide (CH3SCH3; DMS).

49. Its major breakdown product Ismethanethiol (CH3SH), assimilated by bacteria into protein sulfur. Its second volatile breakdown product :-  Dimethyl Sulfide (CH3SCH3; DMS) DMSP DMSP lyase DMS Most DMS in seawater is cleaved from DMSP by the enzyme DMSP lyase, although many non-marine species of bacteria convert methanethiol to DMS

50. DMS is also taken up by marine bacteria, but not as rapidly as methanethiol. Although DMS usually consists of less than 25% of the volatile breakdown products of DMSP, the high reactivity of methanethiol makes the steady-state DMS concentrations in seawater approximately 10 times those of methanethiol (~3 nM vs. ~0.3 nM). Curiously, there have never been any published correlations between the concentrations of DMS and methanethiol. This is probably due to the non-linear abiotic and microbial uptake of methanethiol in seawater, and the comparatively low reactivity of DMS. However, a significant portion of DMS in seawater is oxidized to dimethyl sulfoxide (DMSO). Relevant to global climate, DMS is thought to play a role in the Earth's heat budget by decreasing the amount of solar radiation that reaches the Earth's surface. DMSP has also been implicated in influencing the taste and odour characteristics of various products. For example:- DMSP is odourless and tasteless, it is accumulated at high levels in some marineherbivores or filter feeders. Increased growth rates, vigour and stress resistance among animals cultivated on such diets have been reported.  DMS, is responsible for repellent, 'off' tastes and odours that develop in some seafood products because of the action of bacterial DMSP-lyase, which cogenerates acrylate.