Table 2 Average characteristics of solid-phase extracted dissolved organic matter (SPE-DOM) within the original plume sample and post incubation.

From: Impact of high Fe-concentrations on microbial community structure and dissolved organics in hydrothermal plumes: an experimental study

Sample

m/z

H/C

O/C

AImod

DBE

NOSC

IDEG¥

#Form

DF(C)○

DF(H/C)○

DF(NOSC)○

#Fe–Form

[–]

[–]

[–]

[–]

[–]

[–]

[–]

[–]

[–]

[–]

[–]

[–]

Plume sample (P)

407

1.28

0.45

0.237

8.13

 − 0.34

0.76

1722

2.19

0.080

0.160

94

Initial solution 50:450 (P:C)**

297

1.40

0.34

0.243

5.83

 − 0.66

0.29

–

2.54

0.162

0.246

–

Post incubation samples

Control (C) I

280

1.40

0.31

0.255

5.57

–

–

436

–

–

–

–

Control (C) II

265

1.46

0.29

0.231

5.00

–

–

382

–

–

–

–

Control (C) III

268

1.43

0.30

0.247

5.23

–

–

365

–

–

–

–

Inc 0 µM Fe I

415

1.27

0.46

0.235

8.30

–

–

1820

–

–

–

–

Inc 0 µM Fe II

414

1.27

0.46

0.235

8.26

–

–

1801

–

–

–

–

Inc 0 µM Fe III

415

1.28

0.46

0.235

8.28

–

–

1810

–

–

–

–

Inc 0.1 µM Fe I

414

1.28

0.46

0.235

8.26

–

–

1809

–

–

–

–

Inc 0.1 µM Fe II

409

1.28

0.45

0.237

8.17

–

–

1747

–

–

–

–

Inc 0.1 µM Fe III (†)

373

1.29

0.42

0.257

7.61

–

–

1226

–

–

–

–

Inc 1 µM Fe I

398

1.28

0.44

0.242

8.04

–

–

1464

–

–

–

–

Inc 1 µM Fe II

396

1.28

0.44

0.243

8.00

–

–

1513

–

–

–

–

Inc 1 µM Fe III

393

1.30

0.42

0.244

7.88

–

–

1585

–

–

–

–

Inc 10 µM Fe I (†)

411

1.27

0.47

0.237

8.27

–

–

1771

–

–

–

–

Inc 10 µM Fe II

380

1.29

0.42

0.251

7.72

–

–

1334

–

–

–

–

Inc 10 µM Fe III

367

1.30

0.40

0.258

7.53

–

–

1218

–

–

–

–

Inc 100 µM Fe I (†)

354

1.30

0.39

0.265

7.33

–

–

1237

–

–

–

–

Inc 100 µM Fe II

386

1.29

0.43

0.248

7.83

–

–

1403

–

–

–

–

Inc 100 µM Fe III

379

1.29

0.42

0.251

7.72

–

–

1354

–

–

–

–

Inc 1 mM Fe I (‡)

411 (‡)

1.28

0.46

0.237

8.25

–

–

1799

–

–

–

–

Inc 1 mM Fe II (‡)

364 (‡)

1.31

0.39

0.258

7.47

–

–

1366

–

–

–

–

Inc 10 mM Fe I

355

1.31

0.39

0.263

7.34

–

–

1187

–

–

–

–

Inc 10 mM Fe II

361

1.31

0.39

0.261

7.43

–

–

1282

–

–

–

–

Inc 10 mM Fe III (•)

402 (‡)

1.28

0.45

0.240

8.07

–

–

1679

–

–

–

–

Averages for triplicates with DOM characteristics of the reduced dataset (section = only formulae occurring in all replicates)*

Control (C) section

267

1.43

0.30

0.245

5.20

 − 0.75

–

317

2.64

0.185

0.269

7

0 µM Fe section

414

1.27

0.46

0.235

8.28

 − 0.31

0.80

1794

2.18

0.083

0.168

117

0.1 µM Fe section

411

1.28

0.46

0.236

8.22

 − 0.32

0.79

1741

2.20

0.082

0.166

98

1 µM Fe section

394

1.28

0.44

0.244

7.97

 − 0.38

0.74

1403

2.29

0.081

0.157

28

10 µM Fe section

372

1.30

0.41

0.255

7.60

 − 0.45

0.67

1197

2.43

0.093

0.162

11

100 µM Fe section

381

1.29

0.42

0.250

7.76

 − 0.42

0.69

1309

2.37

0.087

0.158

14

10 mM Fe section

357

1.30

0.39

0.263

7.38

 − 0.50

0.61

1172

2.54

0.101

0.167

8

NEqPIW section (N = 5)

424

1.28

0.45

0.235

8.42

 − 0.33

0.84

1527

2.30

0.079

0.158

–

  1. Values for the 50:450 (P:C) initial solution were calculated from SPE-DOC weighed average characteristics (see Table 1). Average mass of formulae (m/z); elemental ratios (H/C, O/C); average modified aromaticity (AImod); double bond equivalent (DBE) after Koch and Dittmar (2006, 2017); North Equatorial Pacific Intermediate Water (NEqPIW)—in-house standard.
  2. †Excluded from the evaluation of DOM as SPE-TDN exceeds TDN indicating contamination (see Table 1).
  3. ‡Excluded as number of sequences too low for microbial community analysis (see Table 1) and DOM of replicates is inconclusive.
  4. •Excluded from further evaluation of DOM as an outlier as both other replicates are in very good agreement.
  5. *Reduced dataset refers to further evaluation of DOM after exclusion of specific incubations (†, ‡ and •).
  6. **Values for the 50:450 (P:C) initial solution were calculated from plume and control end members.
  7. ¥IDEG of initial solution 50:450 (P:C) based on weighted intensities of control (9×) and plume sample (1×).
  8. ○Diversity indices used by Mentges et al.42; DA Gini-Simpson index; DF(C, H/C, NOSC) Rao's entropy—functional diversity.
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