Table 1 Known variability of Chl-a, SPM and CDOM over the Wadden Sea

Overall variability

Chl-a

Winter, no wind

1

Spring, in blooms

90

mg m⁻³

Rijkswaterstaat (2008)

SPM

Summer, deep channel, slack tide, no wind

1

Winter, 1–2 h before slack tide, windy

4,000

g m⁻³

Rijkswaterstaat (2008)

CDOM

North Sea side, spring or autumn

0.5

Ems river, winter

2.5

Absorption (375) m⁻¹

Spitzer (1981) and Dupouy et al. (1983)

Spatial variation

Chl-a

Depends on location blooms, rivers

Depends on location blooms, rivers

–

SPM

Deep channels

1

Shallows

4,000

g m⁻³

Rijkswaterstaat (2008)

CDOM

North Sea side

0.15

Ems river

>2

Absorption (400) m⁻¹

Hommersom et al. (2009)

Seasonal variation

Chl-a

Winter

Just over 0

Spring

30–70

mg m⁻³

Tillmann et al. (2000)

SPM

Spring/summer

~40

Winter

~70

g m⁻³

Grossart et al. (2004)

However: floc formation and high organic matter content in summer

However: less flocs and organic matter content in winter

Chang et al. (2006), Grossart et al. (2004)

CDOM

Spring/summer

~0.03–0.08

Winter

~0.08–0.22

Raman (308 → 420) nm⁻¹

Lübben et al. (2009), Laane (1982)

Tidal variation (incl. tidal resuspension)

Chl-a

Depends on blooms, rivers, location, wind

Depends on blooms, rivers, location, wind

SPM

Slack tide

5–20

1–2 h before slack tide

14–88

g m⁻³

Poremba et al. (1999)

CDOM

High tide

0.06 (July)

0.9 (Jan.)

Low tide

0.1 (July) 0.15 (Jan.)

Raman (308 → 420) nm⁻¹

Lübben et al. (2009) Values North Sea inlet

Variation in depth (due to resuspension and seepage)

Chl-a

Equal, but with resuspension min. at surface

0–30 (May)

0–15 (July)

Equal, but with resuspension max at bottom

10–100 (May)

0–20 (July)

mg m⁻³

Values Poremba et al. (1999), equal: Lemke et al. (2009)

SPM

Surface

5–20

Bottom

9–50

g m⁻³

Poremba et al. 1999

CDOM

Possibly release at the bottom

Lübben et al. (2009)