Decreased growth of Stylophora pistillata with nutrient-driven elevated zooxanthellae density is largely explained by DIC limitation
High nutrient concentrations are generally known to adversely affect coral calcification. This reduction in calcification rate is often associated with increased zooxanthellae densities, but little is known about the mechanism underlying calcification inhibition. In this study, we assessed the limiting effects of dissolved inorganic carbon (DIC) on growth rates of Stylophora pistillata before and after five weeks of nitrogen and phosphorus enrichment. Nutrient enrichment resulted in a significant increase in zooxanthellae density and inhibition of calcification, measured using the alkalinity anomaly technique. DIC limitation was the main causative factor for this inhibition; a doubling of the bicarbonate concentration not only restored but greatly enhanced calcification rates of colonies with elevated zooxanthellae densities. At high bicarbonate concentration, no significant negative effect of nutrient enrichment on coral growth was found. The causal mechanism behind calcification inhibition due to nutrient enrichment is most likely increased competition for dissolved inorganic carbon, either among the zooxanthellae or between the coral host and its symbiotic dinoflagellates. This highly limiting effect of DIC on coral growth at elevated nutrient concentrations has important implications for coral aquaculture and husbandry.
Dana Riddle continues his intensive exploration of coral nutrition. In part three of his series, he delves deep into the subject of amino acids, including a discussion about amino acid supplements marketed to reefkeepers.
Stony coral nubbins (tentatively identified as Porites lobata; see Figure 1) were exposed to light of the same intensity (128 µmolm²sec) but different spectra for 75 days. Growth rates were determined by weighing the fragments periodically with an analytical balance.
Reefkeepers all know the giant clams Tridacna crocea, T. maxima, T. squamosa, T. deresa, and T. gigas. James W. Fatherree introduces two recently described species of tridacnids, one of which is now making its way into the hobby.
Over the last decades, the husbandry of aquarium corals has risen to a high level. Although captive corals currently exhibit high survival and fast growth, sexual reproduction remains a major hurdle. Closing the life cycle of corals is an important next step in coral husbandry and aquaculture. Below, I will discuss the reproductive biology of scleractinian corals, the challenges associated with sexual reproduction, and future perspectives of coral aquaculture.
Brad's reef aquarium is maturing beautifully, but the road to success was long and difficult. Brad's story is one of perseverance and the good people who supported him through his journey.
While once reefkeepers believed lighting and chemical additives were all we needed to sustain corals, coral nutrition is now recognized as vital for a thriving captive reef. Dana Riddle delves into more detail about foods for coral.
Dana Riddle thoroughly reviews one of the most anticipated and innovative water circulation devices to enter our hobby in some time. How does the Maxspect Gyre XF150 measure up?
Jay Hemdal, Toledo Zoo’s Curator of Fishes and Invertebrates, grants us an inside look at their grand renovation project of the historic public aquarium. The new Toledo Zoo Aquarium will open on March 27, 2015.
Black corals, formally known as Antipatharia, are members of a unique order within the Anthozoa class. These hexacorals are regularly found in the aquarium trade, and are often misidentified as gorgonians. In this article, we discuss the biology of black corals, and offer some suggestions for aquarium husbandry.
All reefkeepers know about the live-sustaining relationship between coral and their symbiotic algae. However, few of us understand how to care and feed zooxanthallae. Dana Riddle examines this topic in depth.
Proposed listing of the Percula clownfish (Amphiprion percula) under the U.S. Endangered Species Act: What it means, and what aquarists need to know (Part 2)
Chris Jury concludes his two part article by exploring each of the threat factors (including additional data as well as NMFS' response) presented in the petition to list Percula clownfish under the ESA.
Proposed listing of the Percula clownfish (Amphiprion percula) under the U.S. Endangered Species Act: What it means, and what aquarists need to know (Part 1)
In part 1 of a two part series, Chris Jury of the Hawai'i Institute of Marine Biology explains in great detail what every aquarist needs to know about the proposed listing of percula clownfish under the Endangered Species Act.
Here's a look at my 125 gallon mixed-reef aquarium. It's not the biggest, fanciest, most colorful, high-tech reef aquarium for sure, but I'm proud of it and want to share what's in it, how it works, and how I take care of it. The details will come, but for now I want to point out that there are several things about it that could be considered unusual by many hobbyists' standards, too.
Product Review: Products for 'Rapid Cycling' of Marine Aquaria: Brightwell Aquatics' MicroBacter7 and Continuum Aquatics' BacterGen.M
Two products were tested under controlled conditions for their abilities to consume/convert carbon and nitrogen-based compounds (referred to as "cycling" by many hobbyists.) Results suggest that, at dosages recommended by the manufacturers, these products contain sufficient numbers of carbon-cycling bacteria to properly inoculate biochemical oxygen demand tests, and ammonia-oxidizing bacteria are present in numbers that can "seed" a sterile environment, and perhaps hasten the aerobic portion of the nitrogen cycle along by a few days when used as a supplement to conventional seeding via live rock, live sand, and hardy "starter" fishes. Potential problems with over-dosing are also discussed.