A potential tool for high-resolution monitoring of ocean acidification.

• Current anthropogenic carbon dioxide emissions generate besides global warming unprecedented acid-ification rates of the oceans. Recent evidence indicates the possibility that ocean acidification and lowoceanic pH may be a major reason for several mass extinctions in the past. However, a major bottleneck forresearch on ocean acidification is long-term monitoring and the collection of consistent high-resolutionpH measurements. This study presents a low-power (<1 W) small sample volume (25l) semiconductor based fluorescence method for real-time ship-board pH measurements at high temporal and spatialresolution (approximately 15 s and 100 m between samples). A 405 nm light emitting diode and the blueand green channels from a digital camera was used for swift detection of fluorescence from the pH sen-sitive dye 6,8-Dihydroxypyrene-1,3-disulfonic acid in real-time. Main principles were demonstrated byautomated continuous measurements of pH in the surface water across the Baltic Sea and the Kattegatregion with a large range in salinity (∼3–30) and temperature (∼0–25◦C). Ship-board precision of salinityand temperature adjusted pH measurements were estimated as low as 0.0001 pH units.

Subject headings

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Klimatforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Climate Research (hsv//eng)

Keyword

Ocean acidification

pH monitoring

Fluorescence

Non-linear calibrations

6

8-Dihydroxypyrene-1

3-disulfonic acid

High-flow/low-flow sampling

6

Publication and Content Type

ref (subject category)

art (subject category)