Growth, calcification, and photobiology of the threatened coral Acropora cervicornis in natural versus artificial light

Abstract

Land‐based coral culture is of increasing interest for conservation and educational display. Shallow water corals generate most of their energy from photosynthesis, and light is a critical abiotic factor in their husbandry. We compared growth, calcification, and photobiology in the coral Acropora cervicornis between natural and artificial (light‐emitting diode; LED) light to better understand the impact of light source on coral performance. One tank of a greenhouse recirculating system at The Florida Aquarium's Center for Conservation was used to culture replicate coral colonies. Half of the tank and corals were covered to block sunlight and illuminated with a commercial reef aquarium LED fixture, while the other half was exposed to natural sunlight. Treatments were matched in terms of maximum photosynthetically active radiation and spectral measurements characterized both light regimes. Coral growth and calcification were tracked over a period of 19 weeks by repeated measurements of total linear extension (TLE) and buoyant weight. For the first 5 weeks, photosynthetic yield was measured weekly using a pulse‐amplitude‐modulated fluorometer. Calcification was significantly higher under LED lighting relative to natural light, but TLE did not differ. Photobiology data suggest that corals in both treatments were acclimated to the same light level, but photosynthetic efficiency was ultimately greater in the natural light treatment. More consistent light delivery and different spectral composition under LED treatment conditions may explain the incongruity between calcification and photosynthetic efficiency. This experiment informs husbandry of shallow‐water scleractinian corals maintained in both natural sunlight and enclosed structures.

A Model for Accurate Determination of Environmental Parameters in Indoor Zoological and Botanical Gardens Supporting Efficient Species Management

“…These significant variations reveal the importance of developing studies determining DLI in the main areas where vegetation is located at the facility, to allow the efficient selection and location of the vegetable species within the enclosure depending on their DLI requirements. The DLI quantification allows us to accurately determine the most suitable location within the enclosure for the selected species, facilitating its adaptation and development [9,12,14]. Furthermore, quantifying DLI allows the correction of light input if DLI values are not the ones desired, which can be increased by adding supplemental light or reduced by providing shade.…”

“…A detailed study of these parameters could help to make a better choice of animal species or a better adaptation of the facility for the existing animals, thus improving their health and well-being [25,27]. Since the DLI sensor is submersible, its usefulness for designing correct lighting in aquatic environments for corals and aquatic plants in aquariums is significant, based on the fact that each species has certain DLI needs [12,28].…”

“…However, there are currently no published studies determining DLI values in interior zoological facilities. Furthermore, the development of DLI determination studies has also proven of great use, not only in terrestrial species but also in aquatic animal and plant species [12]. The design of a habitat where plant and animal species coexist entails that a balance is reached.…”

“…In interior facilities, an environmental parameters design is essential for adequate species choice and distribution; if optimal lighting, temperature, humidity, etc., are not provided, plants will not develop and grow successfully, and the desired aesthetic potential will not be achieved [14]. Considering this, the quantification of light input and environmental parameters such as relative humidity, air, and soil temperature determination acquire a great importance, not only in vegetable production units but also in zoological facilities, in order to evaluate which lighting and environmental installation will be necessary, as well as the effective selection of species based on their environmental requirements [12,14].…”

Repeated ex situ Spawning in Two Highly Disease Susceptible Corals in the Family Meandrinidae

“…Fully controlled ex-situ systems may offer the only means of isolating and precisely studying these factors (e.g. Slagel et al, 2021).…”