Characterizing Coral Condition Using Estimates of Three-Dimensional Colony Surface Area

Abstract

Readily available nitrogen (N) sources such as ammonium nitrate with excessive irrigation present a potential hazard for the environment. The computer program Nitrate Leaching and Economic Analysis Package (NLEAP) is a mechanistic model developed for rapid site-specific estimates of nitrate-nitrogen (NO 3 -N) moving below the root zone in agricultural crops and potantial impacts of NO 3 -N leaching into groundwater. In this study, the value of NLEAP was tested to simulate N uptake by crops and NO 3 -N leaching parameters in large lysimeters under the tomato crop. Three seedlings of tomato variety of H-2274 (Lycopersicum esculentum L.) were transplanted into each lysimeter. N fertilizer at the rate of 140 kg N ha −1 was sidedressed in two split applications, the first half as ammonium sulphate and the second half as ammonium nitrate. The lysimeters were irrigated based on programs of C 0.75, 1.00, 1.25 and 1.50, C referring to class A-Pan evaporation coefficients. Parameters such as leaching index (LI), annual leaching risk potential (ALRP), N available for leaching (NAL), amount of NO 3 -N leached (NL) and amount of N taken up by the crops (NU) were estimated using the NLEAP computer model. To test the ability of model to simulate N uptake and NL, measured values were compared with simulated values. Significant correlations, R 2 = 0.92 and P < 0.03 for the first year and R 2 = 0.86 and P < 0.06 for the second year, were found between measured and simulated values for crop N consumption, indicating that the NLEAP model adequately described crop N uptake under the varied irrigation programs using an optimal N fertilization program for the experimental site. Significant correlations, R 2 = 0.96 and P < 0.01 for the first year and R 2 = 0.97 and P < 0.01 for the second year, were also found between measured and simulated values of NL, indicating that the NLEAP model also adequately predicted NL under the varied irrigation programs. Therefore, this computer model can be useful to estimate the NO 3 -N moving beyond the root zone under conditions in which the present experiment was carried out. Also, the NLEAP-estimated NAL values and other parameters can also be used to improve N management practices and N fertilizer recommendations that will help to decrease the adverse effect of N fertilizer on groundwater quality and farm profitability.

Simple methods for interactive 3D modeling, measurements, and digital databases of coral skeletons

“…Maximum achievable accuracy and precision in measurements of these characteristics should be encouraged (Shortis and Harvey ). These types of measurements are important for determining patterns in biological, biochemical, and physiological attributes, and these parameters have the possibility to be used in conjunction to extract other ecological properties or to be standardized and scaled down to microscopic level or up to ecosystem level (Bythell et al ; Abdo et al ; Courtney et al ; Fisher et al ; Holmes ; Jones et al ; Laforsch et al ; Raz‐Bahat et al ).…”

Development and application of a video-mosaic survey technology to document the status of coral reef communities

“…The rapid patterns of reef decline have also prompted the design of innovative assessment tools to document coral abundance, distribution, and condition rapidly and effectively (Solan et al, 2003;Fisher et al, 2005). With the development of better and more affordable photography and videography techniques and equipment, many programs routinely complement diverbased measurements with digital images of the bottom that are later analyzed using image analysis software (Riegl et al, 2001;Porter et al, 2002).…”

Tracking growth and survival of rescued boulder corals

“…That is, a two‐dimensional area parameter was estimated based on contoured measurements of the colony surface. Three‐dimensional coral size and resultant architectural complexity of reefs are directly responsible for many coral reef ecosystem functions (Loya ); hence, three‐dimensional coral volume estimates may be best suited for estimating reef structural complexity, habitat value, and/or coral reef ecosystem function (Fisher et al ). However, size metrics based on linear skeletal dimensions provide poor resolution of change for slow‐growing boulder corals and hence do not provide a useful tool for tracking growth of individual colonies over medium time scales.…”

“…Colony size during the first two surveys (S01 and S02) was estimated as a volume (cm 3 ) from measurements of linear dimensions (i.e. volume = maximum height × length × width), and that volume was multiplied by the estimated percent live tissue cover to adjust for partial mortality (Fisher et al ). However, it became clear that this approach would not provide estimates of adequate resolution to detect slow growth or resheeting that we hoped to quantify.…”

“…Particularly, a portion of the monitored corals had partial mortality in a “horseshoe” pattern (dead on one side and top with live tissue as a collar shaped rim, likely due to spending a period of time upside‐down following the initial disturbance) that was particularly problematic in this regard. Some studies suggest estimating surface area of head corals using projected linear measurements to calculate surface area as a bottomless hemisphere (Alcala & Vogt ; Fisher et al ). Although this estimation is more accurate than estimating volume, it still requires an estimation of percent live tissue on the entire skeleton and the use of linear measurements (see Fig.…”