ARTICLE IN PRESS

Nuclear Instruments and Methods in Physics Research A 603 (2009) 137–140

Contents lists available at ScienceDirect

Nuclear Instruments and Methods inPhysics Research A

0168-90

doi:10.1

� Corr

E-m

journal homepage: www.elsevier.com/locate/nima

Elements redistribution between organic and mineral parts of microbialmats: SR-XRF research (Baikal Rift Zone)

E.V. Lazareva a,�, A.V. Bryanskaya b, S.M. Zhmodik a, Y.P. Kolmogorov a, O.P. Pestunova c,D.D. Barkhutova d, K.V. Zolotarev e, A.D. Shaporenko e

a Institute of Geology and Mineralogy SB RAS, pr. Ac. Koptug, 3, 630090 Novosibirsk, Russiab Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russiac Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Russiad Institute of General and Experimental Biology SB RAS, Ulan-Ude, Russiae Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia

a r t i c l e i n f o

Available online 3 January 2009

Keywords:

Hot springs

Cyanobacteria

Microbial mats

SR-XRF

Minor and trace elements

02/$ - see front matter & 2009 Elsevier B.V. A

016/j.nima.2008.12.178

esponding author. Tel.: +7 383 333 23 07; fax:

ail address: lazareva@uiggm.nsc.ru (E.V. Lazar

a b s t r a c t

In article minerals formation and elements accumulation in microbial mats of some hot springs of the

Barguzin basin (Baikal Rift Zone) is discussed. The content of a wide spectrum of elements in microbial

mats is studied by means of the method SR-XRF. Regularity of elements accumulation by community

depending on geochemical features of hot spring’s waters are discussed. These elements are distributed

in different ways between organic and mineral substance of the microbial mats. The distribution of K,

Mn, Ni, Cu, Zn, Fe is regular, Ca, Rb, Sr are almost totally related with the mats mineral part, while Ga, Ge

and Br are accumulated in mats organic substance. Germanium element is concentrated in considerable

amounts in the cyanobacterial communities, that develop in sulphideless springs with a higher radon

concentration.

& 2009 Elsevier B.V. All rights reserved.

1. Introduction

Cyanobacteria appeared at the turn of 3.6 billion years ago andhad two number of peaks about 2 and 1 billion years ago [1].During a long period cyanobacteria prevailed and microbial matsare considered to develop occupying vast areas. At present timemicrobial mats in some hot springs are the model object of paleo-geological processes. The reconstruction of the conditions underwhich ancient communities developed is only possible providingthorough studies of modern communities. Though cyanobacterialmats, their structure and composition are well studied from themicrobiological point of view, their geochemical studies are notsufficient. Barguzin basin in the Baikal Rift Zone with its hotsprings is one of those locations where diverse cyanobacterialcommunities develop dynamically. The Alla, Kuchiger and Umkheihot springs are connected with the West Barguzin fault (right sideof Barguzin basin), the Garga and Uro springs are connected withthe East Barguzin one (left side) (Fig. 1). Fractured anisometricgranites or grandiorites serve as water reservoirs. Kuchiger, Umheiand Uro springs pass through quarternary unconsolidated depos-its; Alla and Garga are discharged directly through fissure zones inslightly modified granites, with travertines forming at the orifice

ll rights reserved.

+7 383 3332792.

eva).

points [2,3]. This work sets forth the first data concerningelements content in microbial mats and their distributionbetween the organic matter and mineral component.

2. Methods

Waters composition was defined by a complex of methods withthe cross-check of the results. The methods applied were those ofatom-emission spectrometry, capillary electrophoresis, ICP MS,atomic absorption. To define the species composition of bacteriaand cyanobacteria the mat samples were preserved in 4%formalin, non-preserved samples being stored at 4 1C. Themicrobial mats were layered and then dried under laboratoryconditions. Micromorphology and mineral phases qualitativecomposition research was carried out with the use of the scanningelectron microscope Leo 1430VP (Germany) (the operator S.V.Letov, IGM SB RAS). The organic matter of the microbial mat wasleached with H2O2, heated on a sand bath in order to isolate themineral component.

The samples of the whole mats, of their mineral componentand travertines were analysed via the SR-XRF method. The SR-XRFmethod was used in practice at the element analysis stationVEPP-3 at the synchrotron emission Siberian centre of the NuclearPhysics Institute SB RAS. Energy-dispersive X-ray optical SR-XRFscheme was applied in two modes of the primary monochromatic

ARTICLE IN PRESS

Fig. 1. Hot springs disposition in Barguzin valley. 1—granites, 2—quarternary

deposits, neotectonic faults structures, 3—general (L480 km), 4—regional (Lo80

km), 5—supposed (Atlas of Baikal, 1993) and 6—hot springs under study.

E.V. Lazareva et al. / Nuclear Instruments and Methods in Physics Research A 603 (2009) 137–140138

emission 23 and 36 KeV [4]. Processing of issue spectra wascarried out by means of program AXIL.

Fig. 2. (a) Amorphous SiO2 in a microbial mat and (b) calcite forming in a

cyanobacterial mat.

3. Results

From the geochemical point of view the Barguzin valley rightbead and left bead hot springs differ a little. All the springs arealkaline silicate hydro-therms with the nitrogen prevailing in thegas composition [5–7]. The Alla, Kuchiger and Umkhei springswaters belong to the same type and represent HCO3–SO4–Naaccording to their major and minor elements composition. Thesesprings are HS�-bearing and low Rn (4 eman) concentrations. TheGarga and Uro spring water are characterized by the absence ofHS� in the solution and radon content 30–10 eman. Barguzinbasin hot springs distinguishing feature is persistently high F�

(11–16 ppm) and Si (30–40 ppm) concentration. In trace elementscomposition alkaline, alkaline-earth (Li, Rb, Sr, Cs, Ba) andanionogenic elements (Ge, Mo, W) prevail.

Over a vast area at the Alla river bottom microbial mats arewidespread. There are four types of microbial communitiespointed out. At the temperatures above 55 1C thermophiliccyanobacteria Phormidium spp. and green filamentous bacteriumChloroflexus develop. Directly beside the orifice anoxygenic matcalled after its prevailing species Chloroflexus is being formed [8].While the temperature lowers down to 40–45 1C Phormidium sp.and Oscillatoria sp. (the mat Phormidium) predominate. As thetemperature lowers down to 35 1C (between 35 and 20 1C)genus Thiothrix, along with a little number of genera Oscillatoria

and Phormidium and diatoms do develop (Thiothrix communities).

At the lowest temperatures brown fouling appear, represented bya cyanobacterial mat with Scytonema predomination. GenusPhormidium (Scytonema mat) is represented less.

It might be because of low temperatures (up to 43 1C) in theKuchiger spring communities that species of Oscillatoria genusbecame Phormidium codominants. Oscillatoria limosa and Phormi-

dium foveolarum prevailed in the microbial communities whichdeveloped at the temperature of 43 1C. There was a quantity ofdiatom algae registered. In a green film that developed along theoutflow of the one of numerous streams a maximal speciesdiversity can be pointed. Here large masses of bacteria, cyano-bacteria, diatom algae and fungi were found. Phormidium spp.made the mat base at that point.

ARTICLE IN PRESS

E.V. Lazareva et al. / Nuclear Instruments and Methods in Physics Research A 603 (2009) 137–140 139

Unlike the Kuchiger spring communities, based upon Oscillatoria

species the Umkhei spring communities were featured byPhormidium spp. prevailing in their species composition at themoment of research. Thus Ph. foveolarum and Phormidium sp.made 95% of abundance and biomass of a multilayer microbialmat, the spreads of which were noticed in a warm lake. Therewere isolated forms of Oscillatoria limosa, Ph. tenue and Ph.

angustissimum registered.Along the Garga thermal spring outflow cyanobacterial mat

with Phormidium angustissimum prevailing intensively growstarting with the temperature level of 60 1C. Some particular thinlayers with Mastigocladus laminosus prevailing can be discrimi-nated. Microbial mat dry up and is ‘‘mummified’’ when the streamchanges a channel.

In the Uro spring microbial mats 12 species of cyanobacteriawere revealed, as well as 4 species of diatom algae and 1 speciesof thermophilic anoxygenic phototrophic bacteria Chloroflexus

aurantiacus. Maximal prototroph variety has been registered atthe temperature of 40 and 46 1C. At the temperatures higher than40 1C filamentous cyanobacterium Phormidium laminosum pre-vails. At the temperature, lower than 40 1C Oscillatoria limosa

biomass and that of diatom algae increase. Mastigocladus

laminosus cyanobacterium is exposed in all the temperature zonesof the spring, except temperatures higher than 65 1C, when Ph.

laminosum and C. aurantiacus are only observed.Minerals forming have been observed in the Alla, Garga and

Kuchiger microbial mats. Amorphous SiO2 precipitation is estab-lished in the Alla Chloroflexus (Fig. 1a) and Garga mats. Precipita-tion of submicronic particles of minerals of Ba, Bi, Fe, Cu occurstogether with SiO2 deposit. In the Garga cyanobacterial matcalcite is formed (Fig. 2a). In the Alla Thiothrix and Scytonema andGarga mats the deposit of calcite occurs. In all the communitiesexplored calcite crystals are in fact of the same size, which is atestimony of their simultaneous germing (Fig. 2b). In themicrobial Thiothrix community the deposit of sulphur. In Kuchigermicrobial community formation only submicronic particles ofiron sulphide is established.

Elements content in the microbial mat was initially studied asa whole, without division into mineral and organic parts of the

Table 1Elements content in the microbial mats dry matter.

Alla Kuchig

Thiothrix Chloroflexus Scytonema

n 2 6 1 3

S, % 3.9 0.16 0.4 0.37

K, % 0.55 1.06 1.39 1.01

Ca, % 22.2 4.2 11.3 2.3

Mn, % 0.005 0.029 0.030 0.03

Fe, % 0.19 1.36 1.51 1.58

V o5 61.7 55.0 40.7

Ni 9.2 21.1 22.3 17.5

Cu 22.9 22.1 26.7 25.4

Zn 43.6 74.1 108.0 102.7

Ga 3.5 30.6 10.3 27.4

Ge 1.1 9.1 2.9 4.8

Se 13.0 0.3 0.8 0.3

Br 4.5 1.1 4.4 4.3

Rb 7 30 34 50

Sr 365 635 460 915

Mo 0.60 0.80 1.00 0.50

Cd 0.18 0.27 0.43 0.26

Sn 0.40 1.65 1.35 0.80

Sb 0.050 0.133 o0.2 0.09

I 5.44 2.22 1.59 0.51

Cs 0.34 1.72 h.s. 11.40

Pb 2.4 7.5 9.1 4.6

mat. Average sulphur content in the Alla Chloflexus mat, Kuchigerand Uro make 0.16%, 0.2%, 0.25% (Table 1). Higher concentrationshave been ascertained in the Kuchiger mat (0.37%), where ironsulphide forming can be observed, and in the one of Garga whereSO2�

4 concentration in the nutrition solution is the highest.Naturally high sulphur concentration has been ascertained inthe Alla Thiothrix community is 4%. This concentration includesboth sulphur of the organic matter and native sulphur aggrega-tions that are crystallized in the space between filaments ofThiothrix. Se specific deposit in Thiothrix community (13 ppm).Potassium content in Thiothrix is lower than in cyanobacterialmats, where the element concentration makes 1–1.5% in a livingmat. It is significant that in the process of Garga matsmummification potassium concentration decreases.

In microbial mats where the carbonate is not deposited,calcium content does not exceed 4.2% (Table 1). In the matswhere the concentration is higher, the formation of calcite isascertained. Calcite forming within a communities occurs in thesame springs where travertine forming is observed, i.e. in the Allaand Garga. But as our data prove, calcite formation in a microbialmat occurs in case of sufficient calcium concentration in thenutrition solution (more than 25 mg/l). The Chloroflexus matmakes an exception where calcite is not discovered. It is possiblethat the stream high temperature zone conditions bringing SiO2

precipitates along do not make it possible for calcite to deposit; orthe mat conditions with the green filamentous bacteriumChloroflexus do not let carbonate emerge (these are the mattersfor future ascertain).

Mn, Fe, V, Ni, Cu, Zn, Sn and Pb increased concentrations havebeen ascertained in the Umkhei cyanobacterial mat (Table 1).Species composition of the Umkhei community, the main part ofwhich is formed by 95% Phormidium spp., does not supposesignificant difference between other hot spring’s communities.The difference might be caused by metals pollution from theresort situated upon the spring. The use of diverse metallic itemsby people could be the reason that added some additionalelements into microbial mat. The same reason caused rise of zincand iron concentration in the Garga mat, because iron (in formertimes) and zinc (nowadays) pipes were used to deliver the

er Umkhei Garga Uro

Live mat Dry mat

2 3 3 9

0.20 0.4 h.s. 0.25

1.56 0.96 0.52 1.1

3.4 12.6 8.2 3.2

2 0.162 0.415 0.483 0.022

3.71 0.68 0.76 0.83

131.5 37.6 38.4 23.2

40.8 21.6 10.2 14.3

181.0 25.5 20.1 17.9

403.0 408.3 127.7 73.2

26.5 14.3 20.1 24.5

4.9 280.0 271.3 637.4

o0.1 o0.1 0.3 0.6

7.2 10.7 3.9 7.2

65 25 35 40

705 2030 2340 1390

0.90 0.70 0.60 1.10

0.49 0.19 0.11 0.19

2.98 1.01 1.02 0.80

5 0.550 0.297 0.192 0.224

3.60 2.20 3.68 8.87

6.65 9.33 9.54 8.97

16.2 14.8 11.6 8.3

ARTICLE IN PRESS

E.V. Lazareva et al. / Nuclear Instruments and Methods in Physics Research A 603 (2009) 137–140140

solutions to resort buildings. Without taking into account thepolluted communities it can be mentioned that Fe, V and Cdcontent in the sulphide-containing springs microbial mats arehigher (Table 1).

Manganese content in the all microbial mats is not high and isnot more than 0.03% everywhere, except cyanobacterial mat ofGarga spring. Here unlike other springs there is a remarkablemanganese concentration in water.

The Ni, Cu, Zn, Cd and Pb vary a great deal within the microbialmats, that is the reason why it is impossible to understand themechanism of their distribution at the moment. The molybdenumcontent in all the microbial mats is very regular and variesbetween 0.5 and 1 ppm. Ga, Br, Sn, Sb, Cs content value will begiven just for information without discussion. Rubidium concen-trations are relatively constant. There is no dependence observedupon the concentration in nutrition solution. Strontium isaccumulated in the Garga and Uro microbial mats. Maximalconcentrations feature the Garga, where the element content inthe solution is really high.

The main interest of the authors was caused by germanium.The maximal accumulation occurs in the Uro spring cyanobacter-ial mat. The Garga spring is situated at a slope, and the nutrientsolution passes without stoppage through the community thatdevelops upon this slope. Germanium concentration in Uro hotspring solution more low than in Garga hot spring solution.

Microbial mats decisive role in large amount of elementsaccumulation has been determined. Studying of elements dis-tribution between organic and mineral parts of microbial mat has

been investigate for Alla and Garga communities—i.e. for whereactive formation of minerals in mats is observed. These elementsare distributed in different ways between organic and mineralsubstance of the microbial mats. The distribution of K, Mn, Ni, Cu,Zn, Fe is regular; Ca, Rb, Sr are almost totally related with the matsmineral part, while Ga, Ge and Br are accumulated in mats organicsubstance. The microbial mats destruction does not entail Ga, Geand Br transformation into minerals, but results in their beingcarried away by water streams.

Acknowledgements

This work was supported by the RFBR (06-05-64767, 06-05-64957, 08-05-00968-a); IP: 10, 18-16; 96, 114; SS-5736.2008.5;RPN.2.1.1.702, and Program ‘‘BOE’’.

References

[1] G.A. Zavarzin, Herald of the Russian Academy of Sciences 71 (6) (2001) 611.[2] A.V. Tatarinov, et al., Doklady Earth Sciences 403A (6) (2005) 939.[3] A.M. Plyusnin, et al., Russian Geology and Geophysics 41 (4) (2000) 564.[4] Y.P. Kolmogorov, V.A. Trounova, X-ray Spectrom. 31 (2002) 432.[5] I.S. Lomonosov, Geochemistry and Formation of Modern Hydrotherms in the

Baikal Rift Zone, Nauka, Novosibirsk, 1974, 166p (in Russian).[6] I.M. Borisenko, L.V. Zamana, Mineral waters of Buryat ASSR, Buryat Book

Publishing House, Ulan-Ude, 1978, 162p.[7] L.V. Zamana, Russian Geology and Geophysics 41 (11) (2000) 1575.[8] Z.B. Namsaraev, et al., Microbial Communities of alkaline hydrotherms Nauka,

Novosibirsk, 2006, 111p.