Table 1.
Summary of oxygen microprobing and symptoms from hyperspectral images from coral-algae and coral-coral boundaries in the Southern Line Islands.
Figure 1.
Examples of boundaries between coral and algae.
A) Pocillopora sp. vs. Montipora sp., B) algae vs. Montipora sp., C) Montipora sp. and various algae, D) crustose coralline algae vs. crustose coralline algae, and E) diverse interactions including coral, fleshy algae, crustose coralline algae, and other invertebrates.
Figure 2.
Summary of interactions between corals and algae from surveys of Millennium Atoll.
A) Total number of interactions between corals and algae, B) outcome of coral-algal interactions by algal group.
Figure 3.
Comparison of spectra from different algal and coral groups.
A) Relative reflectance of different algae: CCA, red alga, Bryopsis sp., and turf algae. B) Relative reflectance of 4 different corals: Montipora sp. (2), Pocillopora sp., Porites sp., and Acropora sp. C) Slope of coral and algal reflectance spectra, including CCA, red alga, Bryopsis sp., Pocillopora sp., Porites sp., and turf algae.
Figure 4.
Different renderings of hyperspectral images of the interaction zones between the coral Pocillopora sp.and red alga Gracilaria sp.
A) The location of algae (A), coral (C) and cyanobacteria (cy) are indicated in the True Color image. The color coding is determined for True Color using the three bands red (640 nm), green (550 nm), and blue (460 nm); GOC using the three bands green (515 nm), orange (575 nm), and chlorophyll (685 nm); Color IR using the three bands green (550 nm), red (650 nm), and infrared (IR; 860 nm); SR (Simple Ratio) using the ration between 800 nm and 680 nm; NVDI (Normalized Vegetative Density Index) using IR (800 nm) and red (680 nm) in the formula (IR − red)/(IR + red); and ARVI (Atmospherically Resistant Vegetative Index) using the bands IR (800 nm), red (680 nm), and blue (450 nm) entered in the formula (IR − 2*red + blue)/(IR+ 2*red − blue). Each rendering uses a 2% Stretch Contrast Enhancement. B) The slope of the average relative reflectance for the algae, coral, and cyanobacteria imaged in A. Areas used to determine the average reflectance are indicated by hexagons in the IR rendering.
Figure 5.
Dissolved oxygen profiles of coral interaction zones.
Interactions measured were Pocillopora verrucosa vs. Gracilaria sp. (n = 6), Pocillopora verrucosa vs. red turf algae (n = 7), Montipora spp. vs. red turf algae (n = 4), Montipora sp. vs. white band (n = 2), coral vs. CCA (n = 6), and coral vs. coral (n = 1).