Ecophysiology of a Mono Lake picocyanobacterium

Abstract

We isolated an unusual picocyanobacterium (strain MLCB) from alkaline, hypersaline Mono Lake, California. The organism blooms (,5.0 3 10 7 cells L 21 ) in late summer. It has very low population densities in the photic zone through spring and summer (,10 5 cells L 21 ) but maintains a significant population (10 7 -10 8 cells L 21 ) in anoxic, sulfidic waters below 25 m year-round during meromictic periods. Complete turnover of the lake resulted in a significant (.90%) loss of the deep-water population that could not be attributed to simple dilution. The deep-water population returned to its previous concentration by the following autumn. The organism is phycoerythrin rich, does not contain phycourobilin, and is not capable of complementary chromatic adaptation. Phylogenetically, our isolate groups with marine Synechococcus, Prochlorococcus, and Cyanobium genera. Salinity tolerance of our strain was compared to select members of the Cyanobium and showed that strain MLCB was the most halotolerant, capable of growing at 10% salinity, compared to limits of 0-6% for the other strains tested.

Hazenite, KNaMg2(PO4)2{middle dot}14H2O, a new biologically related phosphate mineral, from Mono Lake, California, U.S.A.

“…They can also be sensitive indicators of local climate changes and provide records of paleoclimate (Stine 1994;Jellison et al 1996;Benson et al 1998;Hollibaugh et al 2001). Nevertheless, Mono Lake is subject to recurrent periods of meromixis (persistent chemical stratification) as a consequence of natural and anthropogenic alterations of freshwater flow into the lake, with the most recent episodes persisting from 1995until 2003, and from 2005until 2007(Budinoff and Hollibaugh 2007.…”

“…This terminal lake currently consists of a hypersaline (84-92 g/L), alkaline (pH = 9.8) Na-CO 3 -Cl-SO 4 brine, resulting from evaporative concentration of inflow water, rock weathering, and mineral precipitation (e.g., Garrels and Mackenzie 1967;Li et al 1997;Oremland et al 2004). The lake is endorheic and the basin's volcanic setting includes numerous hydrothermal springs that contribute to its unique water chemistry (Bischoff et al 1991;Council and Bennett 1993;Budinoff and Hollibaugh 2007). High concentrations of boron (∼34 mmol/L) and minor amounts of K, Mg, and Ca are found in the lake (e.g., Bischoff et al 1991).…”

“…Another relatively rare mineral gaylussite, Na 2 Ca(CO 3 ) 2 ⋅5H 2 O, was also found in Mono Lake, which is believed to presently precipitate in a year-round process that probably only began after 1970 when the salinity of the lake exceeded 80‰ (Bischoff et al 1991), owing to the diversion of tributary streams by the Los Angeles Department of Water and Power. The salinity of Mono Lake has steadily increased since 1941 from 50‰ to the current ∼90‰ (Bischoff et al 1991;Budinoff and Hollibaugh 2007;Jørgensen et al 2008 …”

Gene transfer agent (GTA) genes reveal diverse and dynamic Roseobacter and Rhodobacter populations in the Chesapeake Bay

“…The growth medium contained 200 mM NaCl, 50 mM MgSO 4 , 5 mM CaCl 2 , 150 mM K 2 HPO 4 , 8 mM NH 4 Cl, 5 mM Tris-HCl (pH 7.6). Filter-sterilized vitamin, trace metal and iron stock solutions were added to this basal media as described earlier (Budinoff and Hollibaugh, 2007) and these along with DMSP were added to autoclaved salt solutions. Agar plates were prepared with purified agar at 0.8% w/v and kept aerobically in a temperature-controlled incubator (20 1C).…”

High diversity of Rhodobacterales in the subarctic North Atlantic Ocean and gene transfer agent protein expression in isolated strains

“…This enrichment is designed to select for bacteria of the Rhodobacterales order, which often display the ability to use DMSP as a sole carbon and energy source (Buchan et al 2005, Moran et al 2007, Curson et al 2008. The medium contained 150 µM K 2 HPO 4 , 5 mM NH 4 Cl, 500 µM DMSP (Research Plus), vitamins, iron, and trace metals (Budinoff & Hollibaugh 2007) in 0.22 µm-filtered seawater, and was solidified with 1% (w/v) noble agar. The plates were incubated at 20°C in the dark for 2 to 4 d until colonies appeared, and colonies were restreaked on DMSP plates.…”