A morphometric assessment and classification of coral reef spur and groove morphology

Abstract

S0169-555X (16) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.  Four classes of spurs and grooves are formally defined using remote sensing for global application. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Classes correspond to different formation mechanisms with implications for reef platform evolution. Waves are key drivers of feature morphology but width and slope of the fore reef are important. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTConfidential manuscript submitted to Geomorphology AbstractSpurs and grooves (SaGs) are a common and important feature of coral reef fore slopes worldwide. However, they are difficult to access and hence their morphodynamics and formation are poorly understood. We use remote sensing, with extensive ground truthing, to measure SaG mophometrics and environmental factors at 11,430 grooves across 17 reefs in the southern Great Barrier Reef, Australia. We revealed strong positive correlations between groove length, orientation and wave exposure with longer, more closely-spaced grooves oriented easterly reflecting the dominant swell regime. Wave exposure was found to be the most important factor controlling SaG distribution and morphology. Gradient of the upper reef slope was also an important limiting factor, with SaGs less likely to develop in steeply sloping (>5°) areas. We used a subset of the morphometric data (11 reefs) to statistically define four classes of SaG. This classification scheme was tested on the remaining six reefs.SaGs in the four classes differ in morphology, groove substrate and coral cover. These differences provide insights into SaG formation mechanisms with implications to reef platform growth and evolution. We hypothesize SaG formation is dominated by coral growth processes at two classes and erosion processes at one class. A fourth class may represent relic features formed earlier in the Holocene transgression. The classes are comparable with SaGs elsewhere, suggesting the classification could be applied globally with the addition of new classes if necessary. While further research is required, we show remotely sensed SaG morphometrics can provide useful insights into reef platform evolution.

Assessment and Significance of a World War II battle site: recording the USS Emmons using a High-Resolution DEM combining Multibeam Bathymetry and SfM Photogrammetry

“…Numerous spurs and grooves along the ridge are arranged in a NNW–SSE orientation, perpendicular to that of the ridge. Spurs and grooves are the typical geomorphology of a coral reef and consist of elongated narrow ridges and channels that develop along the directions of waves or currents (Kan et al ., ; Duce et al ., ).…”

Wave-driven geomorphology of Pacific carbonate coastlines: from landscape to wavelength scale

“…That net reef accretion occurs at all implies that sediment capable of generating appreciable abrasion is scarce on reef surfaces, particularly as sediment cover would also hinder coral growth. However, shore-normal grooves common to fore reefs often contain a thin veneer of coarse sediment and show signs of abrasion (Duce et al, 2016;Cloud Jr., 1954). Thus, not only are grooves potentially formed through abrasion, they may also promote reef growth by sequestering abrasive tools.…”

“…Briefly, the magnitude of abrasion rates in my experiments implies that abrasive sediment is either very rare on coral reefs or sequestered such that it cannot abrade the majority of the reef surface. In fact, numerous previous studies have observed that coarse sediment accumulates as a thin layer in many fore reef grooves (Duce et al, 2016;Cloud Jr., 1954;Gischler, 2010).…”

“…Additionally, field observations (e.g. Blanchon and Jones, 1995;Cloud Jr., 1954) and geostatistical analysis (Duce et al, 2016) suggest wave-driven abrasion is the primary driver of the formation of fore reef grooves, which are longshore-periodic channel-like structures that are potentially important for reef ecosystem health (Storlazzi et al, 2011). Explaining the formation and accurately predicting the evolution of hardbottom coastal environments requires knowledge of the relationships between abrasion rate and wave and sediment characteristics.…”

Morphological Precision Assessment of Reconstructed Surface Models for a Coral Atoll Lagoon

“…In addition, coral reefs have suffered under the effects of human activities, including overfishing, destructive fishing, pollution, and habitat change due to coastal development, which have caused their degeneration [12][13][14]. The changes have affected the growth, transportation, degradation, and deposition of coral reefs, which have had important effects on their macro-and micro-morphological changes, causing the coral reefs to have highly dynamic geomorphology [15][16][17]. Therefore, the geomorphic evolution study of coral reefs is significant for their exploitation, protection, and management.…”