Hydrothermal Vent Communities How Life Originated?

Hydrothermal vent discovery-1977

Cold seawater sinks down through the crust. O2 and K are removed from the seawater. Ca, SO4, and Mg are removed from the fluid. Na, Ca, and K from the crust enter the fluid. Highest temperatures (350-400 oC), Cu, Zn, Fe, and H2S from the crust dissolve in the fluids. Hot & acidic fluids with dissolved metals rise up through crust. The hydrothermal fluids mix with cold, O2-rich seawater. Metals and sulfur combine to form metal-sulfide minerals: MnO2, FeO(OH), … Sea Water sinks through the crust and is filtered Do Vents Affect the Entire Ocean? The world’s oceans contain many chemicals other than water and salt. Where do these chemicals come from? Rivers carry some of the chemicals into the ocean. Hydrothermal vents supply others. When seawater seeps down into the ocean crust and is heated by the magma, it undergoes lots of chemical reactions. When the fluid rises up through the seafloor, it carries many new chemicals with it, such as copper and zinc. These chemical reactions also remove chemicals from the seawater, such as oxygen and magnesium. Here is a look at some of the many chemical reactions that take place. Cold seawater sinks down through cracks in the crust. 2. Oxygen and potassium are removed from the seawater. 3. Calcium, sulfate, and magnesium are removed from the fluid. 4. Sodium, calcium, and potassium from the surrounding crust enter the fluid. 5. The fluids have reached their highest temperatures. Copper, zinc, iron, and sulfur from the crust dissolve in the fluids. 6. Hot fluids carrying dissolved metals rise up through crust. 7. The hydrothermal fluids mix with cold, oxygen-rich seawater. Metals and sulfur combine to form black metal-sulfide minerals. Basically cold seawater is converted to a very hot fluid rich in dissolved metals. Promotes robust chemistry  initial phase of life?

Robust and complex chemistry www.pmel.noaa.gov/vents

Black & White smokers 2. As the water heats up, it reacts with the rocks in the ocean crust All oxygen is removed.; It becomes acidic. It picks up dissolved metals, including iron, copper and zinc. It picks up hydrogen sulfide. 3.The hot rising fluids carry the dissolved metals and hydrogen sulfide with them. 4. The hydrothermal fluids exit the chimney and mix with the cold seawater. The metals carried up in the fluids combine with sulfur to form black minerals called metal sulfides. These tiny mineral particles give the hydrothermal fluid the appearance of smoke. Many factors trigger this reaction. One factor is the cold temperature of the seawater. A second equally important factor is the presence of oxygen in the seawater. Without oxygen, the minerals would never form. 2. The seawater continues to seep far below this point in the ocean crust. Energy radiating up from molten rock deep beneath the ocean floor raises the water's temperature to around 350-400°C. As the water heats up, it reacts with the rocks in the ocean crust. These chemical reactions change the water in the following way: All oxygen is removed. It becomes acidic. It picks up dissolved metals, including iron, copper and zinc. It picks up hydrogen sulfide. 3. Hot liquids are less dense and therefore more buoyant than cold liquids. So the hot hydrothermal fluids rise up through the ocean crust just as a hot-air balloon rises into the air. The fluids carry the dissolved metals and hydrogen sulfide with them. 4. The hydrothermal fluids exit the chimney and mix with the cold seawater. The metals carried up in the fluids combine with sulfur to form black minerals called metal sulfides. These tiny mineral particles give the hydrothermal fluid the appearance of smoke. Many factors trigger this reaction. One factor is the cold temperature of the seawater. A second equally important factor is the presence of oxygen in the seawater. Without oxygen, the minerals would never form. In white smokers, the hydrothermal fluids mix with seawater under the seafloor. Therefore, the black minerals form beneath the seafloor before the fluid exits the chimney. Other types of compounds, including silica, remain in the fluid. When the fluid exits the chimney, the silica precipitates out. Another chemical reaction creates a white mineral called anhydrite. Both of these minerals turn the fluids that exit the chimney white.

The beginning chemistry of life?

Hydrothermal Vent Distribution Figure 1. Map of known hydrothermal vent biogeographic provinces and major mid-ocean ridges. Provinces: Pink, western Pacific; green, northeast Pacific; blue, East Pacific Rise; yellow, Azores; red, Mid-Atlantic Ridge; orange, Indian Ocean. Pink, western Pacific; green, northeast Pacific; blue, East Pacific Rise; yellow, Azores; red, Mid-Atlantic Ridge; orange, Indian Ocean

Hydrothermal energy source H2S + O2  SO4 ++ H+ + ATP Chemosynthetic (sulfur oxidizing) Thermophilic Bacteria (up to 120oC) Hot, anoxic, sulfide rich water mixes with Cold oxygenated water Hydrothermal Vents as origin of Life?

Bacteria from 120oC http://mollie.berkeley.edu/~volkman/

Vent biological communities BACTERIA (Bacteria and Archea) 400 morphological invertebrate species New species every 2 weeks during 25 years! Evolutionary Origin Derived from surrounding Deep Sea Derived from Shallow Water species Many evolutionary radiations at species level Many vent taxa originated at other organically enriched environments (cold seeps and whale bones) Vents as stable refugia from Global extinctions

Cold Seeps CH4 + O2  CO2 + H20 +ATP CH4  CH3- + H+ +ATP H2S + O2  SO4 ++ H+ + ATP Hydrocarbon reservoirs “methane bubbling” Continental shelves and Trenches 200 invertebrate species ATP is used as an energy carrier for cells; natural synthesis

Invertebrate food sources Food chain based on sulfur-oxidizing bacteria Symbiosis with Bacteria tube worms Vent Mussels and vent clams Ingestion of Bacteria Grazers (gastropod limpets and snails) Filter Feeders (vent shrimp, polychaete worms, amphipods, anemones) Predators Ventfish, octopus Scavengers Crabs

Tube worms

http://web.uvic.ca/%7Everenat/364-13.jpg

Vent Mussels (Bathymodiolus ) www.divediscover.whoi.edu/i

www.divediscover.whoi.edu/i Vent Clams (Calyptogena)

Vent Shrimp (Bresiliidae) www.ifremer.fr/

Alvinellid worms

Vent limpets http://web.uvic.ca/~abates/

Vent Crabs www.divediscover.whoi.edu/i www.senckenberg.uni-frankfurt.de/ Vent Crabs

Ventfish (Thermarces cerberus)

Light organs in vent organisms www.deepsea.com/

Periferic filter feeders

Sea floor Spreading opens new vent areas over geological time www.pmel.noaa.gov/vents/PlumeStudies

Depends on ambient temperature Chemical Reactions Depends on ambient temperature A beehive of activity. Microbial niches in serpentinization- influenced environments at the Lost City hydrothermal field. (A) Exothermic serpentinization reactions within the subsurface produce fluids of high pH enriched in methane and hydrogen, as well as some hydrocarbons. (B) Environments within the warm interior of carbonate chimneys in contact with end-member hydrothermal fluids host biofilms of Methanosarcina-like archaea (green circles). These organisms may play a dominant role in methane production and methane oxidation within the diverse environments present in the chimneys. Bacterial communities within these biotopes are related to the Firmicutes (purple rodlike cells). These organisms may be important for sulfate reduction at high temperature and high pH. (C) Moderate-temperature (40° to 70°C) endolithic environments with areas of sustained mixing of hydrothermal fluids and seawater support a diverse microbial community containing Methanosarcina-like archaea, ANME-1 (a methane-oxidizing phylotype; blue rectangular cells), and bacteria that include

Hydrothermal Vent Communites 25 years of exploration have revealed: A new phylum At least 20 new families Over 90 new genera Over 300 new species Over 250 new strains of free-living bacteria Biomass Up to 30 kg/m2 1000 x greater than typical biomass observed on deep-sea floor Geol 104/BioES 154

Hydrothermal Vent Macrofauna: Environmental Constraints on Life Cycles and Reproduction Suitable vent environments for these organisms are rare. Individual vents have short life-spans. Volcanic eruptions and earthquakes pose further hazards. These conditions favor rapid growth rates, continuous reproduction, and high fecundity. Geol 104/BioES 154