Figures and data
Quantification of chlorophyll, bacteriochlorophyll, carotenoids and the UV-protective pigment scytonemin in samples from three different beachrock zones (Bars ± error bars indicate means ± standard deviation; n = 3). Additional data are available in the Suppl. Materials showing color micrographs (Figure 1 - figure supplement 1) and hyperspectral images (Figure 1 – figure supplement 2) of beachrock cross-sections.
Luminescence lifetime imaging of dissolved oxygen on a black beachrock sample. (A) Experimental setup used for luminescence lifetime imaging of O2 in beachrock. Schematic drawing of the setup showing a side view of the chamber and the imaging system (left) and a frontal view of the experimental chamber (right). The beachrock sample is tightly pressed against the planar optode, using glass slides behind the sample, ensuring close contact. A computer controls the luminescence lifetime camera (PCO SensiCam SensiMod) used for read-out, as well as the trigger unit, triggering the blue LED (460 nm) exciting the luminescent dyes in the optode. All edges of the chamber are covered with black tape, to avoid scattering within the chamber walls. A calibrated NIR LED array or a halogen lamp was used to illuminate the beachrock surface from above with defined spectral photon irradiance levels. (B) Left: digital microscope image of the used sample. Middle: Outlined sample on a 2D image of O2 distribution (false color) acquired after equilibration in darkness. Right: Overlay of the sample outline with the digital microscope image. (C) Middle and Right: Color coded O2 distribution imaged after irradiation with white light [417 µmol photons m-2 s-1 (338400-700nm + 79700-780nm µmol photons m-2 s-1) and 86 µmol photons m-2 s-1 (70400-700nm + 16700-780nm µmol photons m-2 s-1)] for 65 minutes and 60 minutes, respectively. (D) Color coded O2 distribution imaged after illumination for 60, 65 and 60 minutes, respectively, with (left) a 740 nm LED unfiltered (1033 µmol photons m-2 s-1; 66400-700nm + 967700-780nm µmol photons m-2 s-1), (middle) a 740 nm LED + NIR-70N long pass filter (484 µmol photons m-2 s-1; 6400-700nm + 478700-780nm µmol photons m-2 s-1), and (right) a 740 nm LED + NIR-75N long pass filter (15 µmol photons m-2 s-1; 0.1400-700nm + 15.0700-780nm µmol photons m-2 s-1). Additional data for brown and pink beachrock sections are available in the Suppl. Materials (Figure 2 - figure supplements 1 and 2) along with spectra of the white and NIR light sources (Figure 2 – figure supplement 3) and a calibration curve of the planar optode (Figure 1 – figure supplement 4)
Gas exchange measurements of net photosynthesis (PN) and respiration (R) in samples from three different beachrock zones illuminated with visible light (VIS; 400-700 nm) and NIR (740 nm). Symbols ± error bars indicate means ± standard deviation; n=3). A schematic drawing of the experimental setup is available in the Suppl. Materials (Figure 3 - figure supplement 1).
Areal gross photosynthesis rates in samples from three different beachrock zones illuminated with visible light (VIS; 400-700 nm) and NIR (740 nm). Symbols ± error bars indicate means ± standard deviation; n=3)
Beachrock samples used for O2 imaging. Digital microscope images of black (A), brown (B) and pink (C) beachrock samples at various magnifications (see scale bar in each panel). The microscope images were taken after completion of the O2 imaging.
Hyperspectral reflectance imaging of beachrock samples. Left: Black (A), brown (B) and pink (C) beachrock samples with and without selected regions of interest (color coded) of similar spectral composition. Right: Spectral information retrieved from the selected regions. Hyperspectral reflectance measurements were conducted subsequently to the O2 mapping experiments.
Luminescence lifetime imaging of dissolved oxygen on a brown beachrock sample. (A) Left: digital microscope image of the used sample. Middle: Outlined sample on a 2D image of O2 distribution (false color) acquired after equilibration in darkness. Right: Overlay of the sample outline with the digital microscope image. (B) Middle and Right: Color coded O2 distribution imaged after irradiation with white light (417 µmol photons m-2 s-1 (338400-700nm + 79700-780nm µmol photons m-2 s-1) and 86 µmol photons m-2 s-1 (70400-700nm + 16700-780nm µmol photons m-2 s-1)) for 65 minutes and 50 minutes, respectively. (C) 2D images of dissolved O2 acquired after 60 minutes irradiation with (left) a 740 nm LED unfiltered (131 µmol photons m-2 s-1 ; 9400-700nm + 122700-780nm µmol photons m-2 s-1), (middle) a 740 nm LED + NIR-70N long pass filter (484 µmol photons m-2 s-1; 6400-700nm + 478700-780nm µmol photons m-2 s-1), and (right) a 740 nm LED + NIR-75N long pass filter (22 µmol photons m-2 s-1; 0.1400-700nm + 22700-780nm µmol photons m-2 s-1).
Luminescence lifetime imaging of dissolved oxygen on a pink beachrock sample. (A) Right: digital microscope image of the used sample. Middle: Outlined sample on a 2D image of O2 distribution (false color) acquired after incubation in darkness. Left: Overlay of the sample outline with the digital microscope image. (B) Middle and Right: Imaged O2 distribution, after irradiation with white light [417 µmol photons m-2 s-1 (338400-700nm + 79700-780nm µmol photons m-2 s-1) and 86 µmol photons m-2 s-1 (70400- 700nm + 16700-780nm µmol photons m-2 s-1)] for 55 minutes and 40 minutes, respectively. (C) Imaged O2 distribution after 60, 60 and 55 minutes illumination, respectively, with (left) a 740 nm LED unfiltered (1033 µmol photons m-2 s-1;66400-700nm + 967700-780nm µmol photons m-2 s-1), (middle) a 740 nm LED + NIR-70N long pass filter (484 µmol photons m-2 s-1; 6400-700nm + 478700-780nm µmol photons m-2 s-1), and (right) a 740 nm LED + NIR-75N long pass filter, 15 µmol photons m-2 s-1 (0.1400-700nm + 15700-780nm µmol photons m-2 s-1).
Spectra of the light sources used in the O2 imaging experiments. A) Single 740 nm LED with and without NIR-70N and NIR-75N longpass filter; B) three 740 nm LEDs LED with and without NIR-70N and NIR-75N longpass filter; C) used white halogen lamp (Schott KL2500 LCD), D) all combined.
Calibration curve of the O2 planar optode and the correlating Stern-Volmer Plot. The calibration curve was fitted with an exponential decay function (R2=0.997) and the Stern-Volmer Plot with the simplified Two-Site Model (Eq. 2) (R2=0.999). Symbols and error bars represent means ± standard deviation of pixel values across the imaged part of planar optode.
Experimental chamber used for gas-exchange measurements on beachrock. (A) Schematic drawing of experimental setup. (B) Photo of beachrock sample mounted in gas-exchange chamber. Note that the sides of the sample are shielded from light exposure by black tape. The O2 concentration in the chamber is monitored with an optical O2 sensor patch mounted on the inside and read-out by an optical fiber, which is mounted on the outside of the transparent Perspex chamber wall and connected to a fiber-optic O2 meter. The sensor patch was covered by a black O2 permeable optical isolation to avoid interference from background light on the sensor signal. Stirring in the chamber is induced by a small magnet mounted on the chamber wall and driven by a magnetic stirrer positioned next to the chamber. The chamber was illuminated from above with LED light of known intensity and spectral composition.
