Benthic Image analysis classification scheme

For the purposes of this image analysis, corals are defined as those that are responsible for the persistent, hard, three-dimensional structure of a coral reef. In general, this classification will include all members of Order Scleractinia, as well as some other small groups of non-scleractinian corals with hard skeletons, including fire corals (Family Milleporidea), blue coral (Order Helioporacea), and Stylasterid hydrocorals (Family Stylasteridae).

For the purposes of this image analysis, this category groups a collection of fairly related organisms that do not produce a substantial, rigid calcium carbonate skeleton and therefore are neither reef-builders nor do they lay new foundations for future corals. This classification will include members of Subclass Alcyonaria (octocorals), except blue coral and the organ pipe coral, which includes true soft corals, sea fans, sea whips, sea pens, and also members of the Order Antipatheria (black corals).

For the purpose of these image analyses, CCA is defined as any calcified, hard, non-segmented, encrusting or branched, red (or pink) alga.

Turf algae is a category that includes numerous species from multiple evolutionary groups (red algae, green algae, brown algae, and cyanobacteria). These types of mixed algal assemblages are typically short in stature (< 2 cm in height), and often contain filamentous algae (hair-like morphologies) as opposed to fleshy algae (thick branched or sheet-like morphologies).

Any alga whose structure can be seen in the photograph should be labeled as a macroalga rather than turf. Macroalgae possess numerous different types of morphologies that resemble leaves, blades, umbrellas, ferns, grapes, balls, feathers, branched shrubs, etc. Some macroalgae do possess calcification; however, for the purpose of image analyses here, calcified and fleshy representatives (with the exception of Halimeda sp., below) will be lumped together.

Many organisms besides corals and algae are found in coral reef ecosystems. This Tier 1 classification is to be used for animals that are permanently affixed to the substrate. Animals with ability to move about the substrate or swim are classified as Mobile Fauna.

Photographs capture a solitary instant in time. As a result, creatures that are not permanently affixed to a single location on the sea floor (e.g. sea cucumbers, sea stars, sea urchins, fish) sometimes also appear in photographs intended for benthic analysis. While every effort should be made to discern what the benthic classification is underneath the mobile fauna, if that is not possible, this classification category should be used. This is both a Tier 1 and Tier 2 classification category.

Sediment describes a "soft" benthos smaller than rubble (i.e. < 5 mm) which due to it's unsettled nature generally, but not always, is devoid of organisms growing on the individual gains comprising the sediment. However, sea grasses, macroalgae including Halimeda spp., and blue-green algae (a.k.a. cyanobacteria) can be found in soft sediment areas. If a classification point falls on an identifiable organism growing in sediment, that's what should be used for the point classification. The sediment classification should only be used if point falls on the sediment itself.

A particular analysis point may be unclassified because image quality was poor, because not enough of the surrounding area is visible to definitively classify the organism underneath the point, because the benthos is obstructed by something other than mobile fauna, tape, wand, or shadow (e.g. bubble or smear on the camera lens, high turbidity in the water column).

This category is appropriate when the point falls on the transect tape/line or tape hardware.

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