Photochemical transformation of dissolved organic matter in aquatic environment : From a boreal lake and Baltic Sea to global coastal ocean

(1)

DEPARTMENT OF ENVIRONMENTAL SCIENCES

FACULTY OF BIOLOGICAL AND ENVIRONMENTAL SCIENCES

DOCTORAL PROGRAMME IN INTERDISCIPLINARY ENVIRONMENTAL SCIENCES UNIVERSITY OF HELSINKI

Photochemical Transformation of Dissolved Organic Matter in Aquatic Environment ^– from a Boreal Lake and Baltic Sea to Global Coastal Ocean

HANNA AARNOS

dissertationesscholadoctoralisscientiaecircumiectalis

,

alimentariae

,

biologicae

.

universitatishelsinkiensis

18/2016

18/2016

Helsinki 2016 ISSN 2342-5423 ISBN 978-951-51-2357-2

Recent Publications in this Series

1/2016 Hanna Help-Rinta-Rahko

The Interaction Of Auxin and Cytokinin Signalling Regulates Primary Root Procambial Patterning, Xylem Cell Fate and Differentiation in Arabidopsis thaliana

2/2016 Abbot O. Oghenekaro

Molecular Analysis of the Interaction between White Rot Pathogen (Rigidoporus microporus) and Rubber Tree (Hevea brasiliensis)

3/2016 Stiina Rasimus-Sahari

Effects of Microbial Mitochondriotoxins from Food and Indoor Air on Mammalian Cells 4/2016 Hany S.M. EL Sayed Bashandy

Flavonoid Metabolomics in Gerbera hybrida and Elucidation of Complexity in the Flavonoid Biosynthetic Pathway

5/2016 Erja Koivunen

Home-Grown Grain Legumes in Poultry Diets 6/2016 Paul Mathijssen

Holocene Carbon Dynamics and Atmospheric Radiative Forcing of Different Types of Peatlands in Finland

7/2016 Seyed Abdollah Mousavi

Revised Taxonomy of the Family Rhizobiaceae, and Phylogeny of Mesorhizobia Nodulating Glycyrrhiza spp.

8/2016 Sedeer El-Showk

Auxin and Cytokinin Interactions Regulate Primary Vascular Patterning During Root Development in Arabidopsis thaliana

9/2016 Satu Olkkola

Antimicrobial Resistance and Its Mechanisms among Campylobacter coli and Campylobacter upsaliensis with a Special Focus on Streptomycin

10/2016 Windi Indra Muziasari

Impact of Fish Farming on Antibiotic Resistome and Mobile Elements in Baltic Sea Sediment 11/2016 Kari Kylä-Nikkilä

Genetic Engineering of Lactic Acid Bacteria to Produce Optically Pure Lactic Acid and to Develop a Novel Cell Immobilization Method Suitable for Industrial Fermentations

12/2016 Jane Etegeneng Besong epse Ndika

Molecular Insights into a Putative Potyvirus RNA Encapsidation Pathway and Potyvirus Particles as Enzyme Nano-Carriers

13/2016 Lijuan Yan

Bacterial Community Dynamics and Perennial Crop Growth in Motor Oil-Contaminated Soil in a Boreal Climate

14/2016 Pia Rasinkangas

New Insights into the Biogenesis of Lactobacillus rhamnosus GG Pili and the in vivo Effects of Pili15/2016 Johanna Rytioja

Enzymatic Plant Cell Wall Degradation by the White Rot Fungus Dichomitus squalens

16/2016 Elli Koskela

Genetic and Environmental Control of Flowering in Wild and Cultivated Strawberries

17/2016 Riikka Kylväjä

Staphylococcus aureus and Lactobacillus crispatus: Adhesive Characteristics of Two Gram-Positive Bacterial Species

YEB

HANNA AARNOS Photochemical Transformation of Dissolved Organic Matter in Aquatic Environment

(2)

Faculty of Biological and Environmental Sciences Department of Environmental Sciences

Aquatic Sciences University of Helsinki

Finland

PHOTOCHEMICAL TRANSFORMATION OF DISSOLVED ORGANIC MATTER

IN AQUATIC ENVIRONMENT

FROM A BOREAL LAKE AND BALTIC SEA TO GLOBAL COASTAL OCEAN

Hanna Aarnos

ACADEMIC DISSERTATION

To be presented, with the permission of the Faculty of Biological and Environmental Sciences of the University of Helsinki, for public examination in the Auditorium 1041, Biocenter 2, Viikki (Viikinkaari 5, Helsinki) on 2 September 2016,

at 12 noon.

Helsinki 2016

(3)

6XSHUYLVRU 'U$QVVL99lKlWDOR

'HSDUWPHQWRI%LRORJLFDO DQG(QYLURQPHQWDO 6FLHQFH8QLYHUVLW\RI-\YlVN\Ol)LQODQG

5HYLHZHUV 3URI5RJHU-RQHV

'HSDUWPHQWRI%LRORJLFDO DQG(QYLURQPHQWDO 6FLHQFH8QLYHUVLW\RI-\YlVN\Ol)LQODQG

3URI'DYLG-.LHEHU

'HSDUWPHQW RI &KHPLVWU\ 6WDWH 8QLYHUVLW\ RI 1HZ <RUN&ROOHJHRI(QYLURQPHQWDO 6FLHQFHDQG

)RUHVWU\86$

2SSRQHQW 3URI6WHIDQ%HUWLOVVRQ

'HSDUWPHQWRI(FRORJ\ DQG*HQHWLFV/LPQRORJ\

DQG6FLHQFHIRU/LIH/DERUDWRU\8SSVDOD8QLYHUVLW\

6ZHGHQ

&XVWRV 3URI-XNND+RUSSLOD

'HSDUWPHQWRI(QYLURQPHQWDO 6FLHQFHV 8QLYHUVLW\RI+HOVLQNL )LQODQG

,661RQOLQH

,6%13') KWWSHWKHVLVKHOVLQNLIL

,661SDSHUEDFN

,6%1SDSHUEDFN

'LVVHUWDWLRQHV6FKROD 'RFWRUDOLV 6FLHQWLDH&LUFXPLHFWDOLV $OLPHQWDULH

%LRORJLFDH

+DQVDSULQW +HOVLQNL

(4)

ABSTRACT

$VGLVVROYHGRUJDQLFPDWWHU'20FRQVWLWXWHVDYDVWUHVHUYRLURIFDUERQDQG QXWULHQWV LQ ODNHV ULYHUV DQG RFHDQ LW SOD\V DQ LPSRUWDQW UROH LQ WKHJOREDO FDUERQ DQG QXWULHQW F\FOH 2QO\ D SDUW RI '20 PROHFXOHV DUH GLUHFWO\

ELRORJLFDOO\ XWLOL]DEOH E\ EDFWHULD EXW VRODU UDGLDWLRQ LQGXFHG SKRWRFKHPLFDO UHDFWLRQV PD\ PLQHUDOL]H '20 WR LQRUJDQLF IRUPV VXFK DV GLVVROYHG LQRUJDQLF FDUERQ ',& DQG DPPRQLXP 1+ DQG GHJUDGH QRQODELOH '20 PROHFXOHV WR ODELOH VXEVWUDWHV DYDLODEOH IRU EDFWHULD 7KLV GLVVHUWDWLRQ H[DPLQHG WKH SKRWRFKHPLFDO WUDQVIRUPDWLRQ RI '20LQWKHVXUIDFHZDWHULQ GLIIHUHQW VFDOHV RI DTXDWLF HQYLURQPHQWV IURP D)LQQLVKERUHDOODNHDQGWKH

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

,Q WKH %DOWLF 6HDWKHSHODJLFKHWHURWURSKLFEDFWHULRSODQNWRQZDVFDUERQ OLPLWHG LQGLFDWLQJ ORZ ELRDYDLODELOLW\ RI '20 LQ WKH VXUIDFH ZDWHU ,UUDGLDWLRQV RI WKH ZDWHUV ZLWK QDWXUDO RU VLPXODWHG VRODU OLJKW UHVXOWHG LQ SKRWREOHDFKLQJ RI FKURPRSKRULF GLVVROYHG RUJDQLF PDWWHU &'20 DQG SKRWRWUDQVIRUPDWLRQ RI '20 WR LQRUJDQLF FDUERQ DQG QLWURJHQ DV ZHOO DV ODELOH '20 VXEVWUDWHV 7KLV GLVVHUWDWLRQ VKRZHG WKDW LQ WKH %DOWLF 6HD WKH DQQXDO SKRWRSURGXFWLRQ RI DPPRQLXP FRUUHVSRQGHG WR ±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± RI WRWDO EDFWHULDO ELRPDVV DFURVV WKH HQWLUH %DOWLF 6HD,QWKH%DOWLF6HDDVZHOODVLQ WKH PHVRKXPLF ODNH VWXGLHG WKH SKRWRO\WLF ZDWHU OD\HU ZDV VKDOORZ DQG OLPLWHGWKHSKRWRWUDQVIRUPDWLRQ RI'20WRWKHWRSFP

,Q WKH JOREDO VFDOH WKH DQQXDO ',& SKRWRSURGXFWLRQ IURP WHUULJHQRXV

&'20LQIURQWRIWKHWHQULYHUVVWXGLHG7J&\FRUUHVSRQGHGWR RIDQQXDO IOX[RIWHUULJHQRXV'2&RIWKHULYHUV:KHQH[WUDSRODWHG WR D JOREDO HVWLPDWH 7J RI WHUULJHQRXV '2& ZDV DQQXDOO\

PLQHUDOL]HGWR',&E\VRODUUDGLDWLRQLQFRDVWDOZDWHUV*OREDOO\WKHDPRXQW

(5)

RI SKRWRPLQHUDOL]DWLRQ RI WHUULJHQRXV '2& ZDV ODUJHU LQ FRDVWDO RFHDQ WKDQ LQ ODNHV DQG UHVHUYRLUV +RZHYHU WKH DUHDO UDWHV RI ',& SKRWRSURGXFWLRQ ZHUH ODUJHU LQ WKH ODNHV DQG UHVHUYRLUV WKDQLQWKHFRDVWDOZDWHUVLQGLFDWLQJ WKDWSKRWRWUDQVIRUPDWLRQRIWHUULJHQRXV'2& ZDVOLNHO\OLPLWHGE\UHODWLYHO\

VKRUWUHVLGHQFHWLPHVLQLQODQGZDWHUV7RFRQFOXGHWKHSKRWRWUDQVIRUPDWLRQ LQ FRDVWDO ZDWHUV IRUPHG WKH ILQDO VLQN IRU ULYHULQH WHUULJHQRXV &'20 DQG '2& EXW ZDV UHVWULFWHG LQ JHQHUDO WR D IHZ KXQGUHGNLORPHWUHVIURPULYHU PRXWKVWRWKHRFHDQZLWKWKHH[FHSWLRQRIODUJHVWGLVFKDUJLQJULYHUV

(6)

LIST OF ORIGINAL PUBLICATIONS

7KLV WKHVLV LV EDVHG RQ WKH IROORZLQJ SXEOLFDWLRQV UHIHUUHG WR LQ WKH WH[W E\

WKHLUURPDQQXPHUDOV

, +RLNNDOD / $DUQRV + DQG /LJQHOO 5 &KDQJHV LQ QXWULHQW DQG FDUERQ DYDLODELOLW\ DQG WHPSHUDWXUH DV IDFWRUV FRQWUROOLQJEDFWHULDOJURZWKLQWKHQRUWKHUQ%DOWLF6HD(VWXDULHV

DQG&RDVWV±

,, 9lKlWDOR $9 $DUQRV + +RLNNDOD / DQG /LJQHOO 5 0LFURELDO OLQN WKURXJK WKH SKRWRFKHPLFDO WUDQVIRUPDWLRQ RI WHUUHVWULDO GLVVROYHG RUJDQLF PDWWHU VXSSRUWV KHWHUR DQG DXWRWURSKLF SURGXFWLRQ LQ FRDVWDO ZDWHUV 0DULQH (FRORJ\

3URJUHVV6HULHV

,,, $DUQRV + <O|VWDOR 3 DQG 9lKlWDOR $9 6HDVRQDO SKRWRWUDQVIRUPDWLRQ RI GLVVROYHG RUJDQLF PDWWHU WR DPPRQLXP GLVVROYHG LQRUJDQLF FDUERQ DQG ODELOH VXEVWUDWHV VXSSRUWLQJ EDFWHULDO ELRPDVV DFURVV WKH %DOWLF 6HD-RXUQDO RI *HRSK\VLFDO

5HVHDUFK ± %LRJHRVFLHQFHV YRO * GRL

-*

,9 $DUQRV + *pOLQDV < .DVXULQHQ 9 DQG 9lKlWDOR $9 3KRWRFKHPLFDO PLQHUDOL]DWLRQ RI ELRORJLFDOO\ QRQODELOH ULYHULQH '2& WR GLVVROYHG LQRUJDQLF FDUERQ LQ FRDVWDO ZDWHUV VXEPLWWHG IRUSXEOLFDWLRQ LQ*OREDO%LRJHRFKHPLFDO&\FOHV

7KH RULJLQDO SXEOLFDWLRQV LQFOXGHG LQ WKLV WKHVLVDUH UHSURGXFHG E\ WKH NLQG SHUPLVVLRQVRI6SULQJHU6FLHQFHDQG%XVLQHVV0HGLD,,QWHU5HVHDUFK,, DQG$PHULFDQ*HRSK\VLFDO8QLRQ ,,,,9

(7)

$87+25¶6 &2175,%87,2N TO THE PUBLICATIONS

, 5 /LJQHOO SODQQHG WKH VWXG\ + $DUQRV LPSOHPHQWHGWKHVWXG\

ZLWK / +RLNNDOD XQGHU WKH JXLGDQFH RI 5 /LJQHOO / +RLNNDOD DQG 5 /LJQHOO DQDO\VHG WKH GDWD LQFOXGLQJ RUWKRJRQDO UHJUHVVLRQ DQDO\VLV / +RLNNDOD + $DUQRV DQG 5 /LJQHOO SUHSDUHG WKH PDQXVFULSW 7KH DUWLFOH ZDV LQFOXGHG LQ WKH GRFWRUDOWKHVLVRI/+RLNNDOD

,, $99lKlWDORDQG5/LJQHOOSODQQHGWKHVWXG\+$DUQRVDQG/

+RLNNDOD FRQGXFWHG WKH ODERUDWRU\ H[SHULPHQWV ZLWK WKH JXLGDQFH DQG FRQWULEXWLRQV E\ $9 9lKlWDOR FDUERQ VWDEOH LVRWRSHV DQG 5 /LJQHOO SULPDU\ SURGXFWLRQ + $DUQRV ZDV UHVSRQVLEOH IRU PLFURVFRSLQJ $9 9lKlWDOR SUHSDUHG WKH PDQXVFULSWZLWKFRQWULEXWLRQV E\RWKHUDXWKRUV

,,, + $DUQRVSODQQHGWKHVWXG\ZLWK$99lKlWDORDQG3<O|VWDOR + $DUQRV FRQGXFWHG WKH H[SHULPHQWDO ZRUN ZLWK FRQWULEXWLRQ E\ 3 <O|VWDOR + $DUQRV DQDO\]HG WKH GDWD DQG SUHSDUHG WKH PDQXVFULSWZLWKRWKHUDXWKRUV

,9 + $DUQRV SODQQHG WKH VWXG\ WRJHWKHU ZLWK $9 9lKlWDOR + $DUQRV DQG $9 9lKlWDOR RUJDQL]HG WKH JOREDO ULYHU ZDWHU VDPSOH FROOHFWLRQ < *pOLQDV SURYLGHG VDPSOHV IURP 6W /DZUHQFH 5LYHU(VWXDU\+$DUQRVFRQGXFWHGWKHH[SHULPHQWDO ZRUN WKH GDWD DQDO\VLV DQG WKH PDQXVFULSW SUHSDUDWLRQ ZLWK FRQWULEXWLRQV E\RWKHUDXWKRUV

(8)

SYMBOLS AND ABBREVIATIONS

D&'20Ǌ 6SHFWUDODEVRUSWLRQFRHIILFLHQW RI&'20

&'20 &KURPRSKRULF GLVVROYHGRUJDQLFPDWWHU

&2 &DUERQPRQR[LGH

&2 &DUERQGLR[LGH

&2 &DUERQDWHLRQ

&7') &RQGXFWLYLW\VDOLQLW\WHPSHUDWXUHGHSWKDQGLQVLWXIOXRUHVFHQFH

׋Ǌ $SSDUHQWTXDQWXP\LHOGVSHFWUXPLHSKRWRFKHPLFDO UHDFWLYLW\

į & &DUERQVWDEOHLVRWRSLF VLJQDWXUH ',& 'LVVROYHGLQRUJDQLF FDUERQ '2& 'LVVROYHGRUJDQLF FDUERQ '20 'LVVROYHGRUJDQLF PDWWHU '21 'LVVROYHGRUJDQLF QLWURJHQ '23 'LVVROYHGRUJDQLF SKRVSKRUXV

(D $FWLYDWLRQHQHUJ\RIDFKHPLFDOUHDFWLRQ

*)) *ODVVILEUHILOWHU +&2 %LFDUERQDWHLRQ +&2 &DUERQLF DFLG

+0: +LJKPROHFXODU ZHLJKW!'D +1) +HWHURWURSKLFQDQRIODJHOODWH

+7&2 +LJKWHPSHUDWXUHFDWDO\WLFR[LGDWLRQ

Ǌ :DYHOHQJWKQP

/0: /RZPROHFXODU ZHLJKW'D

1+ $PPRQLXP

12 1LWUDWH 12 1LWULWH

2 2[\JHQPROHFXOH ā2+ +\GUR[\OUDGLFDO

3 3KRVSKRUXV

3$5 3KRWRV\QWKHWLFDOO\DFWLYHUDGLDWLRQQP 32 3KRVSKDWH

32& 3DUWLFXODWHRUJDQLF FDUERQ SU 3KRWRFKHPLFDO SURGXFWLRQ UDWH 368 3UDFWLFDOVDOLQLW\XQLW

526 5HDFWLYHR[\JHQVSHFLHV 7'1 7RWDOGLVVROYHGQLWURJHQ 7'3 7RWDOGLVVROYHGSKRVSKRUXV 72& 7RWDORUJDQLFFDUERQ

89$ 8OWUDYLROHWUDGLDWLRQ QP 89% 8OWUDYLROHWUDGLDWLRQ QP 89& 8OWUDYLROHWUDGLDWLRQ QP

(10)

1 INTRODUCTION

1.1 WHY TO STUDY DISSOLVED ORGANIC MATTER?

1DWXUDO RUJDQLF PDWWHU 120 LV XELTXLWRXV RQ WKH (DUWK DQG LW DSSHDUV PRVWO\ +HGJHV LQ GLVVROYHG IUDFWLRQ LQ DTXDWLF HQYLURQPHQWV GLVVROYHG RUJDQLF PDWWHU '20 7KH DTXDWLF '20 FRQVWLWXWHVDODUJHSRRO RIELRUHDFWLYH FDUERQ DQG WKXV SOD\V D VXEVWDQWLDO UROH LQ WKH JOREDO FDUERQ F\FOH )RU H[DPSOH WKH DPRXQW RI FDUERQ LQ RFHDQLF '20 [ J +DQVHOO HW DO LV FRPSDUDEOH WR WKH DPRXQW RI DWPRVSKHULF FDUERQ GLR[LGH &2 a [ J 6LHJHQWKDOHU 6DUPLHQWR ,W KDV EHHQ HVWLPDWHG WKDW LI RQO\ RI RFHDQLF GLVVROYHG RUJDQLF FDUERQ '2&

GHJUDGHGSHU\HDUWKHDPRXQWRI&2UHOHDVHGZRXOGH[FHHGWKHDPRXQWRI

&2 DQQXDOO\ SURGXFHG E\ IRVVLO IXHO FRPEXVWLRQ +HGJHV'20SRRO DOVR DIIHFWV OLJKW SHQHWUDWLRQ SKRWRV\QWKHVLV DQG FDUERQ DQG QXWULHQW G\QDPLFV LQ DTXDWLF HQYLURQPHQWV 'XH WR WKH FOLPDWH FKDQJH WKH FRQFHQWUDWLRQV RI DTXDWLF '20 JHQHUDOO\ VKRZ LQFUHDVLQJ WUHQGV ZLWK WKH SULPDU\VRXUFHVRULJLQDWLQJ IURPODQG+HHWDO

,Q JHQHUDO WKH VRXUFHV RI '20 LQ VXUIDFH ZDWHUV LQFOXGH LQGLJHQRXV SULPDU\ SURGXFWLRQ DXWRFKWKRQRXV VRXUFHV DQG LQSXWV RI WHUUHVWULDO '20 V\QWKHVL]HGE\WHUUHVWULDOSODQWVLQWKHFDWFKPHQWDOORFKWKRQRXVVRXUFHV,Q WKH ZDWHU FROXPQ '20 LV JHQHUDWHG E\ SURFHVVHV VXFK DV H[WUDFHOOXODU H[XGDWHV RI SK\WRSODQNWRQ HJ 1DJDWD YLUDO O\VLV RU DXWRO\VLV RI SODQNWRQLF RUJDQLVPV GLUHFW H[FUHWRU\ UHOHDVH E\ DOO DTXDWLF RUJDQLVPV

³VORSS\´IHHGLQJRISK\WRSODQNWRQFHOOVGXULQJ]RRSODQNWRQJUD]LQJ/DPSHUW DQG OHDFKLQJ IURP IHFDO SHOOHWV RI ]RRSODQNWRQ DQG SURWR]RD -XPDUV HW DO '20 FDQ EH FRQVLGHUHG DV QRQOLYLQJ RUJDQLF PDWHULDO RU GHWULWXV

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

:HW]HO ZKLFK FRPSOLFDWHV WKH SODQNWRQLF IRRG ZHEV IXUWKHU ,Q DGGLWLRQ WR FDUERQ WKH '20 SRRO SURYLGHV D ODUJH SRWHQWLDO VRXUFH RI QXWULHQWV IRU KHWHURWURSKLF EDFWHULD DQG DOVR IRU DXWRWURSKV LQ WKH ZDWHU FROXPQ RIODNHVULYHUVDQGRFHDQ

(11)

Figure 1 A schematic illustration of microbial loop (circled) and its relationship to the classical plankton food chain. The left and right columns represent heterotrophs and autotrophs, respectively. DOM is released to water column from all trophic levels e.g., via excretion and lysis. Modified from Fenchel 1988.

7KH G\QDPLFV RI KHWHURWURSKLF PLFURRUJDQLVPV DQG LQWHUDFWLRQ ZLWK '20 )LJ KDYH LPSRUWDQW LPSOLFDWLRQV IRU WKH DTXDWLF FDUERQ F\FOH

%HFDXVH WKH '20EDVHG IRRG ZHE OHIW FROXPQ LQ )LJ W\SLFDOO\ FRQWDLQV PRUHWURSKLFOHYHOVWKDQWKHFODVVLFDOIRRGZHEEDVHGRQSULPDU\SURGXFWLRQ PRUH FDUERQ LV ORVW E\ UHVSLUDWLRQ DV &2 GXULQJ WKH WURSKLF WUDQVIHU )XUWKHU IRU H[DPSOH FDUERQ OLPLWDWLRQ RQ KHWHURWURSKLF EDFWHULDO JURZWK PD\LQGLFDWHWKDWDOOHDVLO\GHJUDGDEOH'2&LQWKHZDWHUFROXPQLVFRQVXPHG DQG PLQHUDOLVHG WR &2 7KLQJVWDG /LJQHOO ZKLFK LV SRWHQWLDOO\

UHOHDVHGWRDWPRVSKHUH:KHQEDFWHULDOJURZWKLVOLPLWHGE\QXWULHQWVODELOH '2& LV DOORZHG WR DFFXPXODWH LQ WKH VXUIDFH ZDWHUV DQG VXEVHTXHQWO\

H[SRUWHG WR GHHS ZDWHUV WKXV UHPRYHG IURP WKH DFWLYH FDUERQ F\FOLQJ 3KRWRFKHPLFDO GHFRPSRVLWLRQ VHH EHORZ FDQ EH D SULPDU\ PHFKDQLVP IRU UHPRYLQJ ELRORJLFDOO\ UHFDOFLWUDQW EXW SKRWRUHDFWLYH '20 LQ ODNHV 0RORW 'LOORQ DQG FRDVWDO ZDWHUV 1HOVRQ 6LHJHO ,Q IUHVKZDWHUV KHWHURWURSKLF SURGXFWLRQ EDVHG RQ GHWULWDO '20 DVVLVWHG E\ WKH SKRWRSURGXFHG ODELOH VXEVWUDWHV PD\ FRQWULEXWH VLJQLILFDQWO\ WR WKH ZKROH HFRV\VWHP SURGXFWLYLW\ 9lKlWDOR 7KH SKRWRFKHPLFDO PLQHUDOL]DWLRQ RI QRQODELOH '20 DQG PLFURELDO PLQHUDOL]DWLRQ RI ODELOH '20 FRQWULEXWHWR WKH VXSHUVDWXUDWLRQ RI &2 LQ WKH VXUIDFH ZDWHUV DQG WR WKH H[SRUW RI &2 IURP ZDWHU WR DWPRVSKHUH %HFDXVH RI WKH ODUJH SRRO RI UHDFWLYH FDUERQ LQ '20 WKH ELRWLF DQG DELRWLF PLQHUDOL]DWLRQ RI '20 GLUHFWO\ LQIOXHQFHV DLU ZDWHU &2 H[FKDQJH DQG PXOWLSOHELRJHRFKHPLFDOSURFHVVHV0HGHLURVHWDO

(12)

1.2 DOM STRUCTURE AND REACTIVITY

'LVVROYHG RUJDQLF PDWWHU FRQVLVWV RI D YDVW UHVHUYRLU RI ELRFKHPLFDOO\

KHWHURJHQHRXV RUJDQLF FRPSRXQGV IURP VLPSOH ORZ PROHFXODU ZHLJKW /0: 'D FRPSRXQGV VXFK DV DPLQR DFLGV OLSLGV DQG FDUERK\GUDWHV WR FRPSOH[ DQG KLJK PROHFXODU ZHLJKW +0: !'D FRPSRXQGV VXFK DV KXPLF DQG IXOYLF DFLGV FHOOXORVH FKLWLQ DQG OLJQLQ 'LVVROYHG IUDFWLRQ RI RUJDQLF PDWWHU LV RSHUDWLRQDOO\ VHSDUDWHG IURP WKH SDUWLFXODWH IUDFWLRQ SDUWLFXODWH RUJDQLF PDWWHU320E\ILOWHULQJZLWKJODVV ILEUHILOWHUV*))QRPLQDOSRUHVL]HRIaǋPRUPHPEUDQHILOWHUV±

ǋP 7KH '20 ELRDYDLODELOLW\ FRQWLQXXP FRQWDLQV HJ ODELOH '20 PROHFXOHVWKDWDUHPLQHUDOL]HGRQWKHWLPHVFDOHVRIPLQXWHVWRZHHNV$PRQ DQG %HQQHU ZKLOH '20 PROHFXOHV UHVLVWLQJ PLFURELDO GHJUDGDWLRQ PD\WXUQRYHURQWKHWLPHVFDOHVRIFHQWXULHVWRPLOOHQQLD&DUOVRQ +DQVHOO ,Q WKH RFHDQ RI '2& LV FRQVLGHUHG WR EH ODELOH IRU KHWHURWURSKLF PLFUREHV3J&FRPSDUHGWRRIUHIUDFWRU\IUDFWLRQRIWRWDO'2&

3J & +DQVHOO 2Q WKH RWKHU KDQG 6¡QGHUJDDUG 0LGGHOERH FRQFOXGHG WKDW±RIWRWDO'2&LVODELOHLQODNHVULYHUVDQGVHDZDWHU

1.3 DECOMPOSITION OF DOM

'LVVROYHG RUJDQLF PDWWHU FDQ EH GHFRPSRVHG LQ ELRWLF E\ PLFUREHV DQG DELRWLF SURFHVVHV E\ OLJKW SUHVVXUH RU WHPSHUDWXUH ,Q QDWXUDO VXUIDFH ZDWHUV WKH SUHVVXUHV DQG WHPSHUDWXUHV DUH JHQHUDOO\ WRR ORZ WR SURPRWH GHFRPSRVLWLRQ RI '20 DQG RQO\ PLFURELDO DQG SKRWRFKHPLFDO GHFRPSRVLWLRQ RI'20WDNHVSODFH

$V SUHVHQWHG LQ WKH )LJ KHWHURWURSKLF EDFWHULD FDQ XVH ELRDYDLODEOH '20DVDFDUERQDQGQXWULHQWVRXUFH+HWHURWURSKLFEDFWHULDDOWHUPROHFXODU VWUXFWXUH RI '20 ZLWK HQ]\PDWLF DFWLYLWLHV DW WKH FHOO VXUIDFHV DQG LQFRUSRUDWHODELOHVXEVWUDWHVWREDFWHULDOELRPDVVRUPLQHUDOL]H'2&GLUHFWO\

WR &2 E\ UHVSLUDWLRQ &DUOVRQ +DQVHOO %DFWHULD FDQ GLUHFWO\

DVVLPLODWH RQO\ /0: FRPSRXQGV WKXV +0: FRPSRXQGV PXVW EH K\GURO\VHG WR VPDOOHU VXEVWUDWHV SULRU WKH XSWDNH $PRQ %HQQHU )DFWRUV FRQWUROOLQJ WKH ELRDYDLODELOLW\ RI '20 WR KHWHURWURSKLF EDFWHULD LQFOXGH HJ WKH FKHPLFDO FRPSRVLWLRQ RI '20 FRQFHQWUDWLRQV RI LQRUJDQLF QXWULHQWV WHPSHUDWXUH PLFURELDO FRPPXQLW\ VWUXFWXUH DQG DVVRFLDWHG HQ]\PHV DQG XSWDNH SDWKZD\V &DUOVRQ +DQVHOO )RU H[DPSOH LQ PDQ\ IUHVKZDWHUV ± RI '20 LV UHFDOFLWUDQW DJDLQVW PLFURELDO GHFRPSRVLWLRQ EXW VHQVLWLYH WR SKRWRFKHPLFDO GHFRPSRVLWLRQ 9lKlWDOR

(13)

1.3.1 PHOTOCHEMICAL DECOMPOSITION

$EVRUSWLRQ RI VRODU OLJKW LV D SUHUHTXLVLWH IRU SKRWRFKHPLFDO WUDQVIRUPDWLRQ RI '20 &RORUHGRUFKURPRSKRULFGLVVROYHGRUJDQLFPDWWHULH&'20LVD IUDFWLRQ RI '20 WKDW LQWHUDFWV ZLWK WKH VRODU UDGLDWLRQ (VSHFLDOO\ LQ PDQ\

LQODQG DQG FRDVWDO ZDWHUV &'20 GRPLQDWHV WKH DEVRUSWLRQ RI VRODU UDGLDWLRQ 9lKlWDOR 1HOVRQ 6LHJHO &'20 FDQ EH FRQVLGHUHG DV D UHSUHVHQWDWLYH RI KXPLF VXEVWDQFHV LQGLFDWLQJ WKH WHUUHVWULDO RULJLQ 7KXV OHVV &'20 LV IRXQG LQ WKH RSHQ RFHDQ ZKHUH '20 PDLQO\ RULJLQDWHV IURPDXWRFKWKRQRXV VRXUFHV1HOVRQ 6LHJHO

7KH SKRWRO\WLF UDQJH RI VRODU UDGLDWLRQ VSHFWUXP DSSUR[LPDWHO\ ± QP LV UHVSRQVLEOH IRU WKH SKRWRWUDQVIRUPDWLRQ RI '20 LQ QDWXUDO ZDWHUV7KHSKRWRO\WLFUDGLDWLRQLQFOXGHVPDLQO\VKRUWZDYHOHQJWKVRIYLVLEOH OLJKW QP DQG XOWUDYLROHW 89 UDGLDWLRQ 7KH 89% ± QP UDGLDWLRQ DWWHQXDWHV UDSLGO\ LQWR WKH ZDWHU FROXPQ GXH WR WKH DEVRUSWLRQ RI &'20 DQG WKH ZDWHU PROHFXOHV EXW WKH UROH RI 89$±

QP UDGLDWLRQ LQ WKH '20 SKRWRWUDQVIRUPDWLRQ SURFHVVHV PD\ EH ODUJHU DV LW UHDFKHV GHHSHU ZDWHU FROXPQV 9lKlWDOR 7KH 89&

QP UDGLDWLRQ LV DEVRUEHG E\ R]RQH DOUHDG\ LQ WKH DWPRVSKHUH DQG WKXV GRHV QRW UHDFK WKH ODQG RU ZDWHU VXUIDFH %HFDXVH WKH VKRUW ZDYHOHQJWK UDGLDWLRQ LV DEVRUEHG UDSLGO\ LQ D ZDWHU FROXPQ WKH SKRWRFKHPLFDO GHFRPSRVLWLRQ WDNHV SODFH DW WKH VKDOORZ OD\HUV RI SKRWRO\WLF VXUIDFHZDWHUV

7KH SKRWRO\WLF UDGLDWLRQ LV HQHUJHWLF HQRXJK WR H[FLWH WKH DEVRUEHU HJ

&'20 PROHFXOH HYHQ WKRXJK PRVW RI WKH DEVRUEHG HQHUJ\ LV UHOHDVHG DV KHDW 0RSSHU HW DO $IWHU WKH H[FLWDWLRQ WKH GHJUDGDWLRQ RI SKRWRH[FLWHG PROHFXOH QHHGV RQO\ORZDFWLYDWLRQHQHUJ\(DHJ±N- PRO WR IRUP UDGLFDOV DQG VXEVHTXHQWO\ H[SXOVH &2 FDUERQ PRQR[LGH

&2 RU RWKHU VPDOO PROHFXOHV 9lKlWDOR 7KH H[FLWHG PROHFXOH FDQ DOVR WUDQVIHU WKH H[FLWDWLRQ HQHUJ\ WR RWKHU PROHFXOHV HJ 2 ZKLFK JHQHUDWHV UHDFWLYH R[\JHQ VSHFLHV 526 HJ K\GUR[\O UDGLFDOV ā2+ DQG WKXVFRQVXPHV2LQWKHZDWHUFROXPQ9lKlWDOR7KHSKRWRSURGXFHG 526 PD\ UHDFW ZLWK '20 PROHFXOHV DQG HLWKHU LQFUHDVH RU GHFUHDVH WKH ELRDYDLODELOLW\ RI '20 RU GLUHFWO\ LQKLELW WKH PLFURELDO DFWLYLW\ 0RSSHU HW DO

7KH VRODU UDGLDWLRQ FDQ GHFRPSRVH ELRORJLFDOO\ QRQODELOH '20 L GLUHFWO\ WKURXJK FRPSOHWH SKRWRFKHPLFDO PLQHUDOL]DWLRQ RU LL LQGLUHFWO\E\

LQFUHDVHGELRDYDLODELOLW\RI'20HJ.LHEHUHWDO0RSSHUHWDO /LQGHOO HW DO :HW]HO HW DO 0RUDQ =HSS %HUWLOVVRQ 7UDQYLN 0LOOHU HW DO 7KH SKRWRSURGXFHG /0: FDUERQ\O VXEVWUDWHV VXSSRUWLQJ EDFWHULDO JURZWK LQFOXGH HJ IRUPDOGHK\GH DFHWDOGHK\GH S\UXYDWH R[DODWH DQG RWKHU /0: RUJDQLF DFLGV 9lKlWDOR 0RSSHU HW DO 3KRWRFKHPLFDO UHDFWLRQV FDQ VWLPXODWH EDFWHULDO JURZWK DOVR E\ UHOHDVLQJ LQRUJDQLF QXWULHQWV VXFKDVDPPRQLXP%XVKDZHW DO 0RUHOO &RUUHGRU 9lKlWDOR =HSS +RZHYHU WKH

(14)

PRVWDEXQGDQWSKRWRSURGXFWVWKDWKDYHEHHQGHWHFWHGLQQDWXUDOZDWHUVDUH

&2 DQG &2 RU PRUH FRUUHFWO\ GLVVROYHG LQRUJDQLF FDUERQ ',& LH WKH VXP RI GLVVROYHG &2 FDUERQLF DFLG +&2 ELFDUERQDWH LRQ +&2 DQG FDUERQDWHLRQ&2 .LHEHUHWDO0LOOHU =HSS0LOOHU 0RUDQ %pODQJHU HW DO 0RSSHU HW DO 7KH UDWLR RI &2&2 SKRWRSURGXFWLRQ UDQJHV IURP a WR ! 0LOOHU =HSS :KLWH HW DO 5HDGHU 0LOOHU SRLQWLQJ RXW WKDW &2 LV WKH SULPDU\

SKRWRSURGXFW LQ QDWXUDO ZDWHUV 7KH DPRXQW RI SKRWRSURGXFWLRQ RI ODELOH RUJDQLFVXEVWUDWHVPD\HTXDOWKHSKRWRFKHPLFDOSURGXFWLRQRI&20LOOHU 0RUDQ +RZHYHU WKH LPSRUWDQFH RI VRODU UDGLDWLRQ LQ WKH GHFRPSRVLWLRQRI'20YDULHVVWURQJO\DPRQJWKHDTXDWLFV\VWHPV*UDQpOLHW DO0RORW 'LOORQ &RU\HWDO

(15)

2 OBJECTIVES

7KLV WKHVLV H[DPLQHG WKH SKRWRFKHPLFDO WUDQVIRUPDWLRQ RIGLVVROYHGRUJDQLF PDWWHU '20 LQ GLIIHUHQW VFDOHV RI DTXDWLF HQYLURQPHQWV LQ D )LQQLVK ERUHDOODNHLQWKH%DOWLF6HDDQGLQWKHFRDVWDODUHDVRIWHQJOREDOO\ELJULYHUV 7KH PDLQ IRFXV RI WKLV WKHVLV ZDV LQ WKH TXDQWLILFDWLRQ RI SKRWRFKHPLFDO UHDFWLRQV VXFK DV SKRWRSURGXFWLRQ RI GLVVROYHG LQRUJDQLF FDUERQ ',&,,, ,9DPPRQLXPRUODELOH1,,,,,DQGODELOH'20VXSSRUWLQJEDFWHULD, ,,,,,6SHFLDODWWHQWLRQLVJLYHQWRWKHGHWHUPLQDWLRQRIDSSDUHQWTXDQWXP

\LHOGV IRU SKRWRUHDFWLRQV LH WKH SKRWRFKHPLFDO UHDFWLYLW\ RI '20 $Q RSWLFDO PRGHOOLQJ DSSURDFK ZDV XVHG WR VWXG\ WKH LPSRUWDQFH RI WKHVH SKRWRUHDFWLRQV LQHDFKHQYLURQPHQW

)LUVW WKLV WKHVLV H[DPLQHG ERWK EDFWHULDO DQG SKRWRFKHPLFDO GHFRPSRVLWLRQ RI '20 LQ WKH QRUWKHUQ %DOWLF 6HD GXULQJ D WKHUPDO VWUDWLILFDWLRQ IURP VSULQJ WR ODWH VXPPHU , 7KH QXWULHQW WUHDWPHQW H[SHULPHQWV VWXGLHG WKH NH\ VXEVWUDWHV LQRUJDQLF 1 DQG 3 DQG ODELOH &

OLPLWLQJ EDFWHULDO JURZWK DQG '20 ELRDYDLODELOLW\ DERYH DQG EHORZ WKH VHDVRQDO WKHUPRFOLQH ,Q WKH LUUDGLDWLRQ H[SHULPHQWV WKH SKRWRVWLPXODWLRQ RI EDFWHULDO SURGXFWLRQ DQG SKRWRFKHPLFDO ORVV RI '2& DQG '21 ZHUH GHWHUPLQHGZLWKYHUWLFDOGLVWULEXWLRQDORQJ DVPDOOVFDOHVDOLQLW\JUDGLHQW

6HFRQGO\ WKH WKHVLV DVVHVVHG WKH UHVSRQVH RI KHWHUR DQG DXWRWURSKLF SODQNWRQ WR WKH SKRWRWUDQVIRUPDWLRQ RI '20 GXULQJDVXPPHU1OLPLWDWLRQ LQWKHQRUWKHUQ%DOWLF6HD,,7KHSKRWRVWLPXODWHGSURGXFWLRQDQGELRPDVV RI KHWHURWURSKLF EDFWHULD IODJHOODWHV DQG FLOLDWHV ZHUH H[DPLQHG WRJHWKHU ZLWKWKHG\QDPLFVRISURGXFWLRQ DQGFRPPXQLW\VWUXFWXUHRISK\WRSODQNWRQ )XUWKHUWKLVWKHVLVH[DPLQHG GLUHFWSKRWRFKHPLFDOPLQHUDOL]DWLRQRI'2&

DQG '21 WR ',& DQG 1+ UHVSHFWLYHO\ DQG WKH SKRWRSURGXFWLRQ RI ODELOH '20 VXSSRUWLQJ EDFWHULDO ELRPDVV IURP WKH VDPH ZDWHU VDPSOHV 7KH SKRWRUHDFWLRQVZHUHVWXGLHGDORQJDODUJHVFDOHVDOLQLW\JUDGLHQWLQWKH%DOWLF 6HD GXULQJ VSULQJ VXPPHU DQG DXWXPQ 7KHVH SKRWRUHDFWLRQV ZHUH H[WUDSRODWHGWRUDWHVRYHUWKHZKROH%DOWLF6HDDUHDDFFRUGLQJWRWKHVDOLQLW\

GHSHQGHQFH RI WKH SKRWRUHDFWLRQV 7KH LPSRUWDQFH RI SKRWRWUDQVIRUPDWLRQ ZDVDVVHVVHGE\FRPSDULQJWKHUDWHVWRRWKHU&DQG1IOX[HVLQWKH%DOWLF6HD ,,,

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

±LQWKH6W/DZUHQFH5LYHU(VWXDU\ZDVVWXGLHGPRUHFORVHO\

(16)

3 MATERIAL AND METHODS

3.1 WATER SAMPLE COLLECTION

3.1.1 BALTIC SEA

7KH VWXGLHV RI WKLV WKHVLV ZHUH SDUWO\ FRQGXFWHG LQ WKH%DOWLF6HD)LJ, ,,,,,7KH%DOWLF6HDLVRQHRIWKHZRUOG¶VODUJHVWEUDFNLVKZDWHUEDVLQZLWK D GUDLQDJH DUHD WLPHV DV ODUJH DV WKH VHD DUHD NP 7KLV VKDOORZ PHDQ GHSWK RI P DQG VHPLHQFORVHG VHD KDV D ZDWHU UHQHZDO WLPH RI \UV /HSSlUDQWD 0\UEHUJ 7KH ODUJH ULYHULQH LQSXWV RI IUHVKZDWHU NP \U DQG DOORFKWKRQRXV PDWHULDO UHVXOW LQ D VXUIDFH ZDWHUVDOLQLW\RI±QHDUO\LQ.DWWHJDWFORVHWRWKH1RUWK6HDDQGKLJK FRQFHQWUDWLRQV RI '2& ± PPRO & P DQG'21 ± PPRO 1 P+RLNNDODHWDO

6XUIDFH ZDWHU VDPSOHV ZHUH FROOHFWHG WR H[DPLQH WKH G\QDPLFV DQG UHDFWLYLW\ RI'20LQFRDVWDOZDWHUV)RUWKHDUWLFOH,WKH%DOWLF6HDVDPSOHV ZHUHFROOHFWHGIURPWKUHHVLWHVDORQJDVPDOOVFDOHVDOLQLW\JUDGLHQWOHQJWKRI FD NP D IUHVKZDWHU HQG RI 3RMR %D\ 3MLQ)LJDQRXWHUDUFKLSHODJR VLWHLQ/nQJVNlU/nLQ)LJDQGDQRSHQVHDVLWHDW*XOIRI)LQODQGZLWKD VDOLQLW\RIFD$LQ)LJ3RROHGVXUIDFH±PZDWHUVZHUHVDPSOHG E\ D UHVHDUFKYHVVHO LQ/nDQG$EXWLQ3MWKHVXUIDFHZDWHUPVDPSOH ZDV WDNHQ IURP D GRFN $GGLWLRQDOO\ SRROHG GHHS ± P ZDWHUV ZHUH FROOHFWHGIURP$IRUQXWULHQWWUHDWPHQWH[SHULPHQWV7KHPRQWKO\VDPSOLQJ IROORZHG D VXPPHU SK\WRSODQNWRQ VXFFHVVLRQ IURP WKH PDLQ SRVWVSULQJ EORRP LQ 0D\ WR WKH ODWH F\DQREDFWHULDO EORRP LQ $XJXVW LQ $V DQ H[FHSWLRQ LQ -XO\ D SRROHG VXUIDFH ± P VDPSOH ZDV FROOHFWHG IURP DQ LQQHU DUFKLSHODJR VLWH LQ 6WRUIMlUGHQ 6ILQ )LJ IRU D QXWULHQW WUHDWPHQWH[SHULPHQW

)RUWKHDUWLFOH,,DSRROHGVXUIDFH±PZDWHUVDPSOHZDVFROOHFWHG LQ WKH RXWHU DUFKLSHODJR VLWH LQ /nQJVNlU /n LQ )LJ GXULQJ D 1GHSOHWH SHULRGDIWHUDVSULQJEORRPLQPLG0D\

)RU WKH DUWLFOH,,,ILYH VDPSOLQJ VLWHV ZHUH VDPSOHGDORQJDODUJHVFDOH VDOLQLW\ JUDGLHQW OHQJWK RI FD NP IURP WKH VDOLQLW\ RI LQ WKH 1HYD

%D\ 1% LQ)LJȸUHFHLYLQJWKHODUJHVWIUHVKZDWHUGLVFKDUJHVRIWKH%DOWLF 6HDE\WKH5LYHU1HYDȸWRWKHVDOLQLW\RILQWKH6RXWKHUQ%DOWLF6HD$UNRQD 6HD $6LQ)LJ6XUIDFHZDWHUVDPSOHVIURPFDGHSWKRIPDWWKHRSHQ VHD VDPSOLQJ VLWHV $6 *% *R) DQG +NL LQ )LJ ZHUH FROOHFWHG DXWRPDWLFDOO\ E\ D IORZWKURXJKVDPSOLQJV\VWHPLQDPHUFKDQWVKLSLQ-XO\

DQG 6HSWHPEHU DQG0DUFK&RUUHVSRQGLQJO\SRROHGVXUIDFH P ZDWHU VDPSOHV ZHUH FROOHFWHG E\ D /LPQRVVDPSOHU IURP DUHVHDUFK YHVVHOLQWKH1HYD%D\1%LQ)LJ

(17)

Figure 2 Sampling sites in the Baltic Sea and the Lake Pääjärvi (LP;III). The large-scale salinity transect (III): (AS) Arkona Sea; (GB) Gotland Basin; (GoF) Gulf of Finland;

(Hki) Helsinki; (NB) Neva Bay; and the small-scale salinity transect (I): (A1) Ajax 1;

(Lå) Långskär (II); (Sf) Storfjärden; and (Pj) Pojo Bay.

3.1.2 LAKE PÄÄJÄRVI

$ IUHVKZDWHU VDPSOH IURP D PHVRKXPLF ERUHDO ODNH LQ 6RXWKHUQ )LQODQG /DNH 3llMlUYL /3 LQ )LJ ZDV VWXGLHG IRU YDOLGDWLRQWKHRSWLFDOPRGHOOLQJ IRU SKRWRPLQHUDOL]DWLRQ RI '2& LQ,,,7KH '2& FRQFHQWUDWLRQLVDERXW PPRO&PLQ/DNH3llMlUYL$UYRODHWDO6XUIDFHZDWHUVDPSOHV±

P ZHUH FROOHFWHG E\ D /LPQRVVDPSOHU IURP WKH PLGGOH RI WKH ODNH LQ -XO\DQG$XJXVW

3.1.3 BIG RIVERS

7KHDUWLFOH,9RIWKHWKHVLVZDVFRQGXFWHGZLWKZDWHUVFROOHFWHGIURPJOREDOO\

ELJ ULYHUV $PD]RQ &RQJR 'DQXEH *DQJHV%UDKPDSXWUD /HQD 0HNRQJ 0LVVLVVLSSL 3DUDQi 6W /DZUHQFH DQG <DQJW]H 5LYHUV )LJ 7KHVWXGLHG ULYHUVFRQWULEXWHQHDUO\RQHWKLUGWRERWKIUHVKZDWHUGLVFKDUJHDQG'2&IOX[

(18)

WRWKHJOREDORFHDQ&DXZHW7KH\GUDLQRIWKHODQGDUHDRIWRWDOO\

ILYH FRQWLQHQWV DFURVV YDULDEOH YHJHWDWLRQ DQG FOLPDWH ]RQHV 0LOOLPDQ )DUQVZRUWK

)RU WKH FROOHFWLRQ RI ULYHU ZDWHU VDPSOHV / FOHDQHG DQG HPSW\

SRO\HWK\OHQHFRQWDLQHUVZHUHVKLSSHGWRWKHORFDOFROODERUDWRUVDWHDFKULYHU 7KH\ILOOHGWKHFRQWDLQHUVZLWKQRQVDOLQHZDWHUIURPXSVWUHDPRIWKHIUHVK ZDWHU±VDOWZDWHUWUDQVLWLRQ]RQHGXULQJDVHDVRQRIKLJKGLVFKDUJHEHWZHHQ 0DUFK DQG -XQH 7KH VDPSOHV ZHUH WKXV UHSUHVHQWDWLYH RI WKH '20 GLVFKDUJHG WR WKH FRDVWDO RFHDQ DW WKH WLPH RI VDPSOLQJ 7KH VDPSOHV ZHUH VKLSSHG DV VXFK LQ WKH GDUN WR RXU ODERUDWRU\ IRU H[SHULPHQWV RQ ULYHULQHQRQODELOH'2&

7KH6W/DZUHQFH5LYHU(VWXDU\ZDVH[DPLQHGFORVHUWRTXDQWLI\WKHGLUHFW SKRWRPLQHUDOL]DWLRQ RI '2& WR ',& 6XUIDFH ZDWHU VDPSOHVRI/IURPWKH GHSWKRIPZHUHFROOHFWHGIURPVHYHQVLWHVDORQJDVDOLQLW\JUDGLHQWOHQJWK RIFDNPUDQJLQJIURPWKHIUHVKZDWHUHQGRIWKHHVWXDU\WRWKHVDOLQLW\

RI$LQ)LJLQ-XQH)LOWHUHGPVDPSOHVZHUHVHQWLQWKH GDUN WR RXU ODERUDWRU\ IRU H[SHULPHQWV RQ QDWXUDO PL[WXUH RI ULYHULQH DQG PDULQHQRQODELOH '2&

Figure 3 Globally big rivers studied in this thesis:(A) St. Lawrence; (B) Mississippi; (C) Amazon; (D) Paraná; (E) Danube; (F) Lena; (G) Yangtze; (H) Mekong; (I) Ganges-Brahmaputra; and (J) Congo. Dots and triangles show sampling locations in the rivers and in the salinity transect (range of 0-31) of St. Lawrence River Estuary, respectively.

(19)

3.2 SUMMARY OF METHODS

7KHPHWKRGVXVHGLQWKHQXWULHQWWUHDWPHQWDQGLUUDGLDWLRQH[SHULPHQWVDUH SUHVHQWHGLQWKH7DEOHDQGGHVFULEHGLQGHWDLOLQDUWLFOHV,,9

,Q WKH DUWLFOH,9 WKH SKRWRFKHPLFDO PLQHUDOL]DWLRQ RI ULYHULQHQRQODELOH '2& WR ',& ZDV H[DPLQHG LQ D VHDZDWHU PDWUL[ ZLWK WHQ ULYHUV ,Q WKLV H[SHULPHQW RQO\ FRQFHQWUDWLRQV RI '2& DQG SKRWRSURGXFHG ',& DQG

&'20DEVRUEDQFHZHUHIROORZHG7DEOH+RZHYHUWKHVDPHULYHUZDWHUV DV LQ,9 KDYH EHHQ VWXGLHG HDUOLHU HJ IRU WKH PROHFXODU FRPSRVLWLRQ RI '20 :DJQHU HW DO SKRWRFKHPLFDO LVRWRSLF IUDFWLRQDWLRQ RI '2&

/DORQGH HW DO GLVVROYHG EODFN FDUERQ -DIIp HW DO DQG WKH FRQWULEXWLRQ RI LURQ WR &'20 ;LDR HW DO KHQFH VHYHUDO EDFNJURXQG SDUDPHWHUVKDYHEHHQGHWHUPLQHGEXWH[FOXGHGIURPWKLVWKHVLVDQG,9

3.3 NUTRIENT TREATMENT EXPERIMENTS: FACTORS CONTROLLING BACTERIAL GROWTH (I)

,Q WKH QXWULHQW WUHDWPHQW H[SHULPHQW , IDFWRUV OLPLWLQJ EDFWHULDO JURZWK DQG ELRORJLFDO GHFRPSRVLWLRQ RI '20 ZHUH VWXGLHG ZLWK LQRUJDQLF 1 DQG 3 DQG JOXFRVH& WUHDWPHQWV LQ WKH VXUIDFH ± P DQG GHHS ZDWHU ± P VDPSOHV IURP WKH WKHUPDOO\ VWUDWLILHG RSHQVHD VLWH$DWWKH*XOIRI )LQODQG %DOWLF 6HD )LJ 7KH *))ILOWHUHG VXUIDFH DQG GHHS ZDWHU VDPSOHVZHUHWUHDWHGZLWKHLJKWFRQWUROZLWKRXWWUHDWPHQW1313&1&

3& DQG 13& RU IRXU FRQWURO ZLWKRXW WUHDWPHQW & 13 DQG 13&

FRPELQDWLRQV RI QXWULHQW DGGLWLRQV UHVSHFWLYHO\ 7KH OHYHOV RI DGGHG QXWULHQWV ZHUH FRUUHVSRQGLQJ WR WKH FRQFHQWUDWLRQVIRXQGLQWKHGHHSZDWHU LQ WKH *XOI RI )LQODQG VHH GHWDLOV LQ, 7KH QXWULHQWWUHDWHG VDPSOHVZHUH LQFXEDWHG LQ WKH GDUN IRU G $V WKHLQ VLWX WHPSHUDWXUH DW WKH VXUIDFH ZDWHULQFUHDVHGGXULQJWKHVWXG\VHDVRQWKHLQFXEDWLRQWHPSHUDWXUHVZHUH

& LQ 0D\ & LQ -XQHDQG & LQ -XO\DQG$XJXVW7KHGHHSZDWHU VDPSOHVZHUHLQFXEDWHGDWWKHVDPHWHPSHUDWXUHVH[FHSWLQ$XJXVW&

$GGLWLRQDOO\FRQWURODQG13&WUHDWHGGHHSZDWHUVDPSOHVZHUHLQFXEDWHGDW WKHLQVLWXWHPSHUDWXUHRI&

%DFWHULDO SURGXFWLRQ ELRPDVVHV RI EDFWHULD DQG KHWHURWURSKLF QDQRIODJHOODWHV DQG FRQFHQWUDWLRQV RI RUJDQLF '2& '21 DQG LQRUJDQLF QXWULHQWV 1+ 12 32 ZHUH PHDVXUHG GXULQJ WKH LQFXEDWLRQV VHH PHWKRGVLQ7DEOH

(20)

Table1Summaryofthemethodsusedinthenutrienttreatment(I)andirradiationexperiments(I-IV).Thenumbersreferto1=H.Aarnos, 2=otherauthor,and3=externalservice,-notusedinarticle,*measuredonlyasbackgroundinformationbeforeexperiments. ParameterMethodIIIIIIIV NutrientLightLightLightLight Water chemistryNH4+Phenolhypochloritemethod3-31- NO3-,NO2-ReductionofNO3-toNO2-;colorimetric determinationofNO2-3333- PO43-Colorimetricdeterminationwithmolybdatemethod3-33- TDP,DOPColorimetricdeterminationafterpersulphate oxidation;DOP=TDP-PO43-3-33- DOC,TDN,DONHightemperaturecatalyticoxidation(HTCO); DON=TDN±(NH4++NO3-+NO2-)1,21,21,231 TotalcarbohydratesFerricyanideoxidationoffreereducingsugars, spectrophotometricdetection1,2---- POC,PON,POP į13C

FiltrationonGF/Ffiltersanddeterminationwith massspectrometer(POC);orwithHTCO(PON/P)--3-- FiltrationonGF/Ffiltersanddeterminationwith massspectrometer--2-- CDOMSpectrophotometricdetection-1,21,211 Chlorophyll-aSpectrophotometricdetection2*-2-- DICµ%XEEOLQJFKDPEHU¶PHWKRGE\6DORQHQ---1,21 BacteriaBiomassEpifluorescencemicroscopyofacridineorange stainedcells;cellvolumeswithImageanalysis1111- Bacterialproduction3H-thymidinemethod1,21,21,2-- Phytoplankton andprotistsHNFbiomassEpifluorescencemicroscopyofproflavinestained cells;cellvolumeswithNewPortongrid1111- Biomassofsmall-sized (<2μm)autotrophsPhasecontrastmicroscopyofproflavinestained cells3*-1-- Biomassoflarge-sized (>2μm)autotrophs andciliates PhasecontrastmicroscopyofLugol´ssolution stainedcells3*-1-- Primaryproduction14Cmethod--2-- Environmental parametersTemperature,salinity InsituradiationCTDFsensor Photosensors/spectroradiometer3* -1,2* 3*2* 21,3* 1,2- -

(21)

3.4 IRRADIATION EXPERIMENTS

3.4.1 IN SITU±EXPERIMENT IN THE BALTIC SEA (I)

7KHSKRWRFKHPLFDOGHFRPSRVLWLRQRI'20DQGLWVHIIHFWVRQEDFWHULDOJURZWK ZHUH VWXGLHG LQ VXUIDFH ZDWHUVFROOHFWHGIURPWKUHHVLWHVDORQJDVPDOOVFDOH VDOLQLW\ JUDGLHQW LQ WKH *XOI RI )LQODQG , )LJ 7KH H[SHULPHQW ZDV UHSHDWHGLQ0D\ZLWKDZDWHUVDPSOHIURP$)LJ-XQH3M/nDQG$

-XO\/nDQG$DQG$XJXVW3M/nDQG$)UHVKO\FROOHFWHGSDUWLFOHIUHH ILOWHUHGZDWHUVVHDOHGLQP/TXDUW]JODVVERWWOHVZHUHH[SRVHGWRQDWXUDO VXQOLJKWLQWKHVHDDWGHSWKVRIDQGFPQHDUE\WKHVLWH6M)LJ IRU±K&RUUHVSRQGLQJGDUNFRQWUROVDPSOHVZHUHNHSWLQWKHGDUNQH[W WR WKH LUUDGLDWHG VDPSOHV LQ WKH VHD$IWHUWKHOLJKWH[SRVXUHWKHLUUDGLDWHG VDPSOHV DQG WKH GDUN FRQWUROV ZHUH LQFXEDWHG ZLWK DPELHQW EDFWHULD

PDQGQXWULHQWV13DQGFRQWUROZLWKRXWQXWULHQWWUHDWPHQWLQWKH GDUN IRU G 7KH LQFXEDWLRQ WHPSHUDWXUHV DQG OHYHOV RI QXWULHQW DGGLWLRQV IROORZHG WKH RQHV XVHG LQ WKH QXWULHQW WUHDWPHQW H[SHULPHQWV IRU VXUIDFH ZDWHUVDPSOHV,

'2& DQG '21 FRQFHQWUDWLRQV DQG &'20 DEVRUSWLRQ ZHUH PHDVXUHG EHIRUH DQG DIWHU WKH OLJKW H[SRVXUH DV ZHOO DV GXULQJ WKH GORQJEDFWHULDO LQFXEDWLRQ VHH PHWKRGV LQ 7DEOH $GGLWLRQDOO\ EDFWHULDO SURGXFWLRQ ELRPDVVHV RI EDFWHULD DQG KHWHURWURSKLF QDQRIODJHOODWHVDQG FRQFHQWUDWLRQV RILQRUJDQLFQXWULHQWV1+ 12 32 ZHUHIROORZHGGXULQJWKHEDFWHULDO LQFXEDWLRQV GHWDLOVLQ,

3.4.2 IN SITU±EXPERIMENT IN THE LAKE PÄÄJÄRVI (III)

)RU YDOLGDWLRQ RI WKH RSWLFDO PRGHO XVHG LQ,,,9 (T LQ WKLV WKHVLV WKH PHDVXUHG DQG PRGHOOHG UDWHV RI GLUHFW SKRWRPLQHUDOL]DWLRQ RI '2& WR ',&

ZHUHDVVHVVHGIRUWKHVXUIDFHZDWHURI/DNH3llMlUYL)LJ

7KH ',& SKRWRSURGXFWLRQLQ VLWX LQ WKH ODNH ZDV PHDVXUHG E\ H[SRVLQJ SDUWLFOHDQG',&IUHHZDWHUVDPSOHVGHWDLOVLQ,,,VHDOHGLQP/TXDUW]

WXEHV WR QDWXUDO VXQOLJKW DW GHSWKVRI ± FP IRU K 7KH GDUNFRQWURO VDPSOHVZHUHNHSWLQWKHGDUNQH[WWRWKHLUUDGLDWHGVDPSOHVLQWKHODNH7KH FRQFHQWUDWLRQV RI SKRWRSURGXFHG ',& DQG &'20 DEVRUSWLRQ LQ LUUDGLDWHG DQGGDUNFRQWUROVDPSOHVZHUHGHWHUPLQHGDVGHVFULEHGLQ7DEOH7KHVRODU UDGLDWLRQ ZDV PHDVXUHG ZLWK D VSHFWURUDGLRPHWHU QH[W WR WKHODNHRYHUWKH WLPH RI WKH OLJKW H[SRVXUHV LQ -XO\ DQG $XJXVW DQG FRUUHFWHG E\ WKH DOEHGRRIODNHWRTXDQWLI\WKHUDGLDWLRQLQFLGHQWWRWKHODNHGHWDLOVLQ,,,

7KH '2& SKRWRPLQHUDOL]DWLRQUDWHRYHUWKHZDWHUFROXPQSUPRO&P GZDVFDOFXODWHGE\LQWHJUDWLQJWKHPHDVXUHGUDWHVRYHUWKHGHSWKV(T ݌ݎ ൌ ׬_௭^௭^೘ೌೣ݌݉_଴݁^൫ି௄^೏ǡ೛೘^௭൯

೘೔೙ ݀ݖ

(22)

ZKHUHSPLVWKHUDWHDWDGHSWKRIPPRO&PG.GSPLVWKHH[WLQFWLRQ FRHIILFLHQW IRU SKRWRPLQHUDOL]DWLRQ P ] LV WKH GHSWK P DQG WKH LQWHJUDWLRQJRHVWKURXJKDGHSWKRIP]P LQWRDQLQILQLWHGHSWK]P D [

)RUWKHFRPSDULVRQRIPHDVXUHGDQGPRGHOOHGUDWHVWKHVDPHODNHZDWHU VDPSOH ZDV LUUDGLDWHG DOVR ZLWK D VRODU VLPXODWRULQDODERUDWRU\IRUKWR TXDQWLI\ WKH PRGHOOHG ',& SKRWRSURGXFWLRQ DV GHVFULEHG LQ&K7KH PRGHOOHG DQG PHDVXUHG LQ VLWX UDWHV ZHUH WKHQ FRPSDUHG DIWHU WDNHQWKH GLIIHUHQFHVLQWKHLUUDGLDWLRQ WHPSHUDWXUHV&DQG±&UHVSHFWLYHO\

LQWRDFFRXQWGHWDLOVLQ,,,

3.4.3 STUDIES ON NON-LABILE DOM (II-IV)

7KHSKRWUDQVIRUPDWLRQVPRGHOOHGLQWKHDUWLFOHV,,,9IRFXVHGLQELRORJLFDOO\

QRQODELOH'207KXVWKHELRDYDLODEOH'20ZDVUHPRYHGLQSUHWUHDWPHQWV E\ DPELHQW PLFURELRWD SULRU WR WKH SKRWRFKHPLFDO H[SHULPHQWV 7KH FRQGLWLRQV GXULQJ WKH SUHWUHDWPHQWV DQG LUUDGLDWLRQV DUH VXPPDUL]HG LQ 7DEOHVHHGHWDLOVLQ,,,9

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

Table 2 Pre-treatment and irradiation conditions (details inII-IV). NL = non-labile; BB = bacterial biomass; - not used in article.

II III IV

Focus of the study NL-DON NL-DOM NL-DOC

Study site Baltic Sea Baltic Sea,

Lake Pääjärvi

Ten big rivers, St.

Lawrence Estuary Pre-treatment Sample filtrate 0.2-μm + 10-μm GF/F 1-μm

Duration 6 d 4-37 d 40 d±months

Temperature (°C) 10 22-24 5

Dark vs light Light:dark cycle

under PAR Dark Dark

Nutrient addition PO43-

- -

Irradiation Source of radiation Sun Suntest Suntest

Sample volume (mL) 220 170 12

Duration 12 d 46-71 h 39-43 h

Temperature (°C) 12-15 5 21

Parameters followed See Table 1 DIC, NH4+, BB DIC

3.4.3.1 Photomineralization of DON to ammonium (III)

7KH GLUHFW SKRWRPLQHUDOL]DWLRQ RI '21 WR 1+ LH SKRWRDPPRQLILFDWLRQ ZDV GHWHUPLQHG E\ LUUDGLDWLQJ WKH SDUWLFOHIUHH ZDWHUV DV GHVFULEHG DERYH

(23)

DQG LQ 7DEOH $IWHU WKH LUUDGLDWLRQ WKH &'20 DEVRUSWLRQ DQG WKH FRQFHQWUDWLRQV RI 1+ ZHUHPHDVXUHGIURPWKHLQLWLDOGDUNDQGLUUDGLDWHG VDPSOHV 7DEOH GHWDLOV LQ,,,7KHGLIIHUHQFHEHWZHHQWKHLUUDGLDWHGDQG WKHGDUNFRQWUROVDPSOHVLQGLFDWHGWKHDPRXQWRISKRWRDPPRQLILFDWLRQ

3.4.3.2 Photomineralization of DOC to DIC (III, IV)

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

7KHFRQFHQWUDWLRQVRISKRWRSURGXFHG',&DQGDEVRUSWLRQE\&'20ZHUH PHDVXUHG IURP WKH LQLWLDO GDUN FRQWURO DQG LUUDGLDWHG VDPSOHV DIWHU WKH LUUDGLDWLRQ VHH PHWKRGV LQ 7DEOH GHWDLOV LQ,,,,9 7KH SKRWRFKHPLFDO PLQHUDOL]DWLRQ RI '2& ZDV FDOFXODWHG DV WKH GLIIHUHQFH LQ WKH ',&

FRQFHQWUDWLRQV EHWZHHQLUUDGLDWHGDQGGDUNFRQWUROVDPSOHV

3.4.3.3 Photoproduction of labile substrates supporting hetero- and autotrophs (II, III)

7RVWXG\WKHKHWHURWURSKLFEDFWHULDOUHVSRQVHWRSKRWRSURGXFHGODELOHFDUERQ VXEVWUDWHV ,,, WKH SDUWLFOHIUHH ZDWHU VDPSOHV ZHUH ILUVW LUUDGLDWHG LQ D VLPLODU PDQQHU DV WKH SKRWRDPPRQLILFDWLRQ VDPSOHV DQG XQGHU WKH FRQGLWLRQV VKRZQ LQ 7DEOH 7KHQ WKH LUUDGLDWHG DQG WKH FRUUHVSRQGLQJ GDUNFRQWUROVDPSOHVZHUHLQFXEDWHGZLWKLQGLJHQRXVEDFWHULD*))ILOWUDWH DQG 1 DQG 3 QXWULHQWV LQ WKHGDUNDW±&IRU±G7KHJURZWKRI EDFWHULDO ELRPDVV ZDV IROORZHG GDLO\ VHH PHWKRGV LQ 7DEOH 7KH PDJQLWXGH RI SKRWRVWLPXOXV LQ WKH EDFWHULDO ELRPDVV WXUQHG WR EDFWHULDO FDUERQ ZDV FDOFXODWHG IURP WKH GLIIHUHQFH EHWZHHQ WKH LUUDGLDWHG DQG WKH GDUN FRQWURO VDPSOHV DW WKH KLJKHVW EDFWHULDO FHOO GHQVLWLHV RIWKHLQFXEDWLRQ GHWDLOVLQ,,,

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

(24)

3.5 OPTICAL MODELLING OF PHOTOREACTION RATES

7KH PRGHOOLQJ DSSURDFKXVHGLQWKHDUWLFOHV,,,9LVDSSOLHGIURPWKHSDSHU 9lKlWDOR HW DO 7KH PRGHOOHG SKRWRSURGXFWLRQ UDWHSUP RG IRU D SKRWRSURGXFW HJ ',&1+ RU ODELOH VXEVWUDWHV VXSSRUWLQJ EDFWHULDLVD SURGXFWRIWKUHHVSHFWUD(T

݌ݎ_௠௢ௗ ൌ ׬_ఒ^ఒ^೘ೌೣ߶_ఒ

೘೔೙ ܳ_ఒ൫ܽ_{஼஽ைெǡఒ}ܽ_{௧௢௧ǡఒ}^ିଵ൯݀ߣ

ZKHUH߶Ǌ LV WKH GHWHUPLQHG DSSDUHQW TXDQWXP \LHOG VSHFWUXP IRU D SKRWRUHDFWLRQ (TPRORISKRWRSURGXFWPROSKRWRQV4ǊUHSUHVHQWVWKH VSHFWUXP RI PHDQ DQQXDO SKRWRQ IOX[ GHQVLW\LQ VLWX PRO SKRWRQV P \U QPHVWLPDWHGIRUHDFKVHDVRQLQWKH%DOWLF6HDGHWDLOVLQ,,,,,RULQWKH FRDVWDO RFHDQ LQ WKH IURQW RI HDFK VWXGLHG ULYHU GHWDLOV LQ,9 7KH UDWLR D&'20ǊDWRWǊ GLPHQVLRQOHVV LV D FRQWULEXWLRQ RI &'20 WR WKH WRWDO DEVRUSWLRQ FRHIILFLHQWDWRWǊ P QP HTXDOOLQJ WR LI &'20 DEVRUEV DOO SKRWRQV 7KH LQWHJUDWLRQWKURXJKǊP LQ WRǊP D [DFFRXQWVIRUWKHZDYHOHQJWKV FRQWULEXWLQJ WRDSKRWRUHDFWLRQ

7KH DSSDUHQW TXDQWXP \LHOG VSHFWUXP ߶Ǌ GHVFULEHV WKH DPRXQW RI SKRWRSURGXFWPRORI',&,,,,91+ ,,,RUODELOH&,,,,,RUODELOH 1 ,, ERXQG LQ EDFWHULDO ELRPDVV SURGXFHG SHU DPRXQW RI SKRWRQV DEVRUEHG LQ WKH VDPSOH7KH߶ǊZDVDVVXPHGWRLQFUHDVHH[SRQHQWLDOO\ZLWK GHFUHDVLQJZDYHOHQJWK(T

߶_ఒൌ ܿ݁^ିௗఒ

ZKHUHF GLPHQVLRQOHVV DQGG QP DUH SRVLWLYH FRQVWDQWVDQG Ǌ LV WKH ZDYHOHQJWKQP7KHSDUDPHWHUVFDQGGRI(TZHUHLWHUDWHGWKURXJKDQ XQFRQVWUDLQHG QRQOLQHDU RSWLPL]DWLRQ µIPLQVHDUFK¶ IXQFWLRQ RI 0DWODE VHH GHWDLOVLQ,,,9DQG6XSSOHPHQWDU\PDWHULDOVWKHUHLQ

3.6 CONTAMINATION PRECAUTIONS

7RDYRLGFRQWDPLQDWLRQDOOJODVVZDUHDQGSODVWLFERWWOHVDQGFRQWDLQHUVXVHG LQ,,9ZHUHULQVHGZLWKGHWHUJHQWDQGWDSZDWHU±K\GURFKORULFDFLG DQGILQDOO\ZLWKLRQH[FKDQJHGZDWHU$GGLWLRQDOO\DOOTXDUW]DQGJODVVZDUH DQGJODVVILEUHILOWHUV*))ZHUHSUHFRPEXVWHGDW±&IRUDWOHDVW K 7KH FRQWDLQHUV VDPSOH ERWWOHV DQG ILOWHUV ZHUH ULQVHG WKRURXJKO\ ZLWK VDPSOHZDWHUSULRUWRXVH

(25)

4 RESULTS AND DISCUSSION

4.1 FACTORS CONTROLLING BACTERIAL GROWTH

%DFWHULDO JURZWK DQG '20 ELRDYDLODELOLW\ ZHUH LQYHVWLJDWHGLQIRXUQXWULHQW WUHDWPHQW H[SHULPHQWV WKURXJKRXW D VXPPHU ZKHQ WKHQDWXUDOVXUIDFHDQG GHHS ZDWHU EDFWHULDO VDPSOHV IURP WKH RSHQVHD VLWH *XOI RI )LQODQG ZHUH LQFXEDWHG ZLWKGLIIHUHQW LQRUJDQLF 1 DQG 3 DQG JOXFRVH& FRPELQDWLRQV DQG DW GLIIHUHQW LQFXEDWLRQ WHPSHUDWXUHV IRU G,,QWKHVXUIDFHVDPSOHVWKH SULQFLSDO IDFWRU FRQWUROOLQJ EDFWHULDO SURGXFWLRQ ZDV ELRDYDLODEOH & 7KH JOXFRVH& DGGLWLRQ LQFUHDVHG EDFWHULDO SURGXFWLRQ WKURXJK WKH VWXG\ SHULRG IURP 0D\ WR $XJXVW EXW OHG UDSLGO\ WR LQRUJDQLF QXWULHQW OLPLWDWLRQ$IWHU WKH SRVWVSULQJ EORRP LQ 0D\ DQG GXULQJ WKH VXPPHU QXWULHQW PLQLPXP LQ -XQH DQG -XO\ GHWDLOV LQ , WKH FRPELQHG JOXFRVH& DQG LQRUJDQLF 1 DGGLWLRQ VLJQLILFDQWO\ LQFUHDVHG WKH EDFWHULDO SURGXFWLRQ 'XULQJ WKH F\DQREDFWHULDO EORRP LQ $XJXVW DOVR LQRUJDQLF 3 ZDVQHHGHGLQWKHDGGLWLRQ WR1DQG&IRUDVLJQLILFDQWUHVSRQVHLQ WKHEDFWHULDOSURGXFWLRQ$VLJQLILFDQW UHVSRQVHLQWKHEDFWHULDOELRPDVVZDVSURGXFHGRQO\ZLWKWKHFRPELQDWLRQRI JOXFRVH& DQG ERWKLQRUJDQLFQXWULHQWVWKURXJKRXWWKHVXPPHU2YHUDOOWKH UHVXOWV VXSSRUW WKH HDUOLHU ILQGLQJV WKDW WKH EDFWHULDO JURZWK LV OLPLWHG E\

ERWK ELRDYDLODEOH FDUERQ DQG QXWULHQWV LQ WKH QRUWKHUQ%DOWLF6HD /LJQHOOHW DO .XSDULQHQ +HLQlQHQ /LJQHOO HW DO 7KH JUD]LQJ GLG QRW FRQWURO WKH EDFWHULDO JURZWK LQ , DV QR TXDQWLILDEOH QXPEHUV RI KHWHURWURSKLF QDQRIODJHOODWHV ZHUH IRXQG LQ WKH *))ILOWUDWHV DIWHU G LQFXEDWLRQV

,Q WKH GHHS ZDWHU VDPSOHV WKH DEVHQFH RI ELRDYDLODEOH &FRPELQHGZLWK WKHORZZDWHUWHPSHUDWXUH&OLPLWHGWKHEDFWHULDOJURZWK)XUWKHUQR LQRUJDQLF QXWULHQW DGGLWLRQ DIIHFWHG VLJQLILFDQWO\ WKH EDFWHULDO SURGXFWLRQ GHWDLOV LQ, EHFDXVHWKHLQRUJDQLFQXWULHQWFRQFHQWUDWLRQVUHPDLQHGKLJKLQ WKHGHHSZDWHUVWKURXJKRXWWKHVXPPHU

$V WKH EDFWHULDO JURZWK ZDV &OLPLWHG WKH ELRDYDLODELOLW\ RI '20 ZDV HYLGHQWO\ ORZ LQ WKH *XOI RI )LQODQG , 'HVSLWH RI WKH KLJK VKDUH RI WRWDO FDUERK\GUDWHV ± RI WRWDO '2& ERWK LQ WKH GHHS DQG WKH VXUIDFH ZDWHUV WKH ELRDYDLODELOLW\ RI'2& UHPDLQHG JHQHUDOO\ VPDOO LQGLFDWLQJ WKDW WKH SUHYDLOLQJ FDUERK\GUDWH SRRO ZDV PDLQO\ ELRORJLFDOO\ UHIUDFWRU\ LQ WKH

*XOIRI )LQODQG $V VHHQ LQ WKH FRQFHQWUDWLRQV RI '2&DQG'21,WKHORZ ELRDYDLODELOLW\OHGLQDQDFFXPXODWLRQRI'20LQWKHVXUIDFHZDWHUGXULQJWKH VXPPHU

(26)

4.2 PHOTOTRANSFORMATION OF DOM

([SRVLQJ ZDWHU VDPSOHV WR VRODU UDGLDWLRQ ȸ HLWKHU QDWXUDO RU VLPXODWHG ȸ UHVXOWHG LQ WKH SKRWRWUDQVIRUPDWLRQ RI '20 LQ DOO LUUDGLDWLRQ H[SHULPHQWV

$V WKH DEVRUSWLRQ RI VRODU UDGLDWLRQ LQ '20 PROHFXOHV LV D SUHUHTXLVLWH IRU RFFXUUHQFH RI DQ\ SKRWRUHDFWLRQV WKH GHFUHDVH LQ DEVRUSWLRQ FRHIILFLHQW VSHFWUD RI FKURPRSKRULF '20 D&'20Ǌ ZDV QRWLFHG LQ DOO LUUDGLDWLRQ H[SHULPHQWVWKXVVRODUUDGLDWLRQSKRWREOHDFKHG&'20,,9)RUH[DPSOH LQ ,9WKH LUUDGLDWLRQV SKRWREOHDFKHG RQ DYHUDJH RIWHUULJHQRXV&'20 DWQPDPRQJWKHVWXGLHGULYHUV

7KH SKRWRFKHPLFDO UHDFWLRQV WUDQVIRUPHG '20 WR ODELOH IRUPV ZKLFK FOHDUO\ LQFUHDVHG WKH ELRPDVV ,, ,,, DQG WKH SURGXFWLRQ , ,, RI KHWHURWURSKLF EDFWHULD DV ZHOO DV VWLPXODWHG WKH JURZWK RI KHWHURWURSKLF IODJHOODWHV DQG FLOLDWHV ,, %DFWHULD JUHZ IDVWHU WKH FHOO GHQVLWLHV ZHUH KLJKHUDQGWKHFHOOYROXPHVELJJHULQWKHLUUDGLDWHGVDPSOHVWKDQLQWKHGDUN FRQWURO VDPSOHV UHVXOWLQJ LQ D SKRWRVWLPXOXV RI ± LQ WKH EDFWHULDO ELRPDVV HJ LQ,,, $OVR HJ 0RUDQ =HSS KDYH QRWLFHG D VLPLODU WR WLPH LQFUHDVH RI EDFWHULDO SURGXFWLRQ DQG ELRPDVV GXH WR WKH SKRWRSURGXFWLRQ RIODELOH '20VXEVWUDWHV

,QWKHLQVLWXH[SHULPHQWLQWKH%DOWLF6HD,WKHFRQFHQWUDWLRQVRI'2&

DQG '21 ZHUH JHQHUDOO\ QRW VLJQLILFDQWO\ GLIIHUHQW EHWZHHQ WKH LUUDGLDWHG DQG WKH GDUN FRQWURO VDPSOHV DIWHU WKH ±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

7KHDUWLFOH,,GHPRQVWUDWHGDOHYHOWURSKLFWUDQVIHURIELRORJLFDOO\QRQ ODELOH '20 LQ D ³PLFURELDO ORRS´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

(27)

DPRQJSK\WRSODQNWRQWD[DGHWDLOVLQ,,$VWKHSODQNWRQFRPPXQLW\ZDV1 OLPLWHGGXULQJWKHGELRDVVD\SK\WRSODQNWRQZDVOLNHO\VWLPXODWHGE\WKH SKRWRSURGXFWLRQ RI ODELOH 1 SULPDULO\ DV 1+ EXW LQ VPDOOHU DPRXQWV DOVR DV DPLQR DFLGV 7DUU HW DO 9lKlWDOR $OVR PL[RWURSK\ LH SK\WRSODQNWRQ XVLQJ EDFWHULD DV D VRXUFH RI 1ZKLFKLV D FRPPRQ VWUDWHJ\

IRU DOJDHWRREWDLQQXWULHQWVXQGHUROLJRWURSKLFFRQGLWLRQV=XENRY 7DUUDQ PD\ KDYH H[SODLQHG WKH VWLPXODWLRQ RI FHUWDLQ SK\WRSODQNWRQ WD[D VHHGHWDLOVLQ,,

7KH G\QDPLFV RI WKH SODQNWRQ LQGXFHG E\ WKH SKRWRWUDQVIRUPDWLRQ RI '20 DJUHHG ZLWK WKH G\QDPLFV RI SDUWLFXODWH RUJDQLF FDUERQ 32& DQG QLWURJHQ 321 GXULQJ WKH G ELRDVVD\ ,, 7KH EDFWHULDO ELRPDVV 32&

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į &

LQGLFDWHGWKDW32&DQGWKHELRPDVVRISODQNWRQZHUHSULPDULO\EDVHGRQWKH SKRWRWUDQVIRUPHG DOORFKWKRQRXV '20 LPSRUWHG IURP WKH FDWFKPHQW RI WKH

%DOWLF6HDGHWDLOVLQ,,

$OVR WKH GLIIHUHQFHV LQ ',& ,,,,9 DQG 1+ ,,, FRQFHQWUDWLRQV EHWZHHQ WKH LUUDGLDWHG DQG WKH GDUN FRQWURO VDPSOHV ZHUH VLJQLILFDQWO\

KLJKHU WKDQ WKRVH EHWZHHQ WKH GDUN DQG WKH LQLWLDO ZDWHUV LQGLFDWLQJ WKDW SKRWRFKHPLVWU\ ZDV UHVSRQVLEOH IRU WKH PLQHUDOL]DWLRQ RI '2& DQG '21 GLUHFWO\ WR ',&DQG1+ UHVSHFWLYHO\,Q,9WKH',&SKRWRSURGXFWLRQZDV OLQHDUO\ GHSHQGHQW RQ WKH SKRWREOHDFKLQJ RI WHUULJHQRXV &'20 ZLWK D UHJUHVVLRQFRHI¿FLHQW RIPRO&P^í5 )LJLQ,9

4.3 APPARENT QUANTUM YIELDS

7KH DPRXQW RI SKRWRSURGXFHG ',& ,,,,9 1+ ,,, DQG ODELOH '20 VXSSRUWLQJ EDFWHULD ,,,,, ZDV QRUPDOL]HG ZLWK WKH DPRXQW RI DEVRUEHG SKRWRQV IRU WKH GHWHUPLQDWLRQ RIDSSDUHQWTXDQWXP\LHOGVSHFWUXP߶Ǌ(T )LJ UHSUHVHQWV WKH߶Ǌ VSHFWUD IRU WKH SKRWRUHDFWLRQV VWXGLHG LQ WKLV WKHVLVZLWKWKHFRPSDUDEOH߶ǊVSHFWUDIURPWKHOLWHUDWXUH7KHSDUDPHWHUVIRU FDOFXODWLQJWKH߶ǊV(TDUHUHSRUWHGLQWKHDUWLFOHV,,,97KLVWKHVLVDQG PDQ\ SUHYLRXV VWXGLHV GHVFULEH߶Ǌ ZLWKWZRSDUDPHWHUVUHVXOWLQJLQVSHFWUD ZKLFK LQFUHDVH H[SRQHQWLDOO\ WRZDUGV VKRUWHU ZDYHOHQJWKV )LJ DQG UHIHUHQFHV WKHUHLQ +RZHYHU VRPH VWXGLHV XVH WKUHH SDUDPHWHUV IRU ߶Ǌ UHVXOWLQJ LQ D VOLJKWO\ GLIIHUHQW VKDSH RI߶Ǌ %pODQJHU HW DO 5HDGHU 0LOOHU)LJ%

(28)

Figure 4 Apparent quantum yield spectra for the photoreactions studied inII-IV and from the literature. The photoreactions presented in the panels: (A) photoproduction of NH4+

and labile N; (B) photomineralization of DOC to DIC; and (C) photoproduction of labile DOM supporting bacterial biomass.Note the logarithmic scale on y-axis.