Role of elevated organic carbon levels and microbial activity in coral mortality

Role of elevated organic carbon levels and microbial activity in coral mortality

David I. Kline, Neilan M. Kuntz, Mya Breitbart, Nancy Knowlton, Forest Rohwer

Marine Ecology Progress Series, Vol. 314 (May 22 2006), pp. 119-125

Stable URL:

PDF available

Here we experimentally show that routinely measured components of water quality (nitrate, phosphate, ammonia) do not cause substantial coral mortality. In contrast, dissolved organic carbon (DOC), which is rarely measured on reefs, does.

‘Nuff said!

But the whole article is available, so as usual – click through and read it!

Effect of carbon/nitrogen ratio manipulation in feed supplements on Artemia production and water quality in solar salt ponds in the Mekong Delta, Vietnam

Effect of carbon/nitrogen ratio manipulation in feed supplements on Artemia production and water quality in solar salt ponds in the Mekong Delta, Vietnam

Lulijwa Ronald, Gilbert Van Stappen, Nguyen Van Hoa, Patrick Sorgeloos

DOI: 10.1111/are.12135

Green water (GW) was supplied to all ponds, with the standard Vietnamese procedure of supplying GW and chicken manure (CM) as the control (C/N 1.8). Treatment ponds were supplemented with tapioca (TAP) as carbon source, combined with either CM, pig manure (PM) or rice bran (RB), with C/N ratios of 7.4, 10.5 or 20.1 respectively. After 6 weeks of culture, no single treatment supported both improved water quality and enhanced Artemia production. Overall, improved water quality was observed at C/N 20.1 and higher Artemia production at C/N 7.4.

This is interesting for more than just growing brine shrimp!

Microbial Community Management in Aquaculture

Microbial Community Management in Aquaculture

Procedia Food Science, Volume 6, 2016, Pages 37-39
P. Bossier, P. De Schrijver, T. Defoirdt, H.A.D. Ruwandeepika, F. Natrah, J. Ekasari, H. Toi, D. Nhan, N. Tinh, G. Pande, I. Karunasagar, G. Van Stappen

Under a Creative Commons license

The expansion of the aquaculture production is restricted due to the pressure it causes on the environment by the discharge of waste products in the water bodies and by its dependence on fish oil and fishmeal. Aquaculture using bio-floc technology (BFT) offers a solution to both problems.

All biofloc size classes were consumed and utilized by the shrimp, tilapia and mussel. The highest retention of nitrogen in the animal body, however, was consistently originating from the bioflocs larger than 100μm

Survival in the [immunity] challenge tests with shrimp from the biofloc [fed] groups, was also significantly higher compared to the positive control.

Rather than trying to control microbial community composition, microbial activity can be steered. The disruption of quorum sensing, bacterial cell-to-cell communication, has been suggested as an alternative strategy to control infections in aquaculture 5.

Recent studies also indicate that opportunistic aquatic pathogens[…]are also able to sense host clues such as stress hormones.


Excretion of dissolved organic carbon by phytoplankton of different sizes and subsequent bacterial uptake

Malinsky-Rushansky NZ, Legrand C
Excretion of dissolved organic carbon by phytoplankton of different sizes and subsequent bacterial uptake
MEPS 132:249-255 | Full text in pdf format

One of the more-hidden angles of our reef world.

EOC [excreted organic carbon -Ed) may be important as a source of primary growth substrates for free-living bacteria (Larsson & Hagstrom 1982).  The importance of microbial food chains parallel to the conventional grazing ones in aquatic food webs is now recognised (Azam et al. 1983).  The significance of phytoplankton excretion as contributor to the ‘microbial loop’ has been studied (Cole et a.1. 1982, Brock & Clyne 1984).  EOC contributed to about half of the bacterial carbon requirement in some environments (Larsson & Hagstrom 1982).  Some studies suggested that a considerable amount of the annual primary production passed through the bacterial component (Brock & Clyne 1984),and bacterial production averaged 20% of planktonic primary production (Cole et al. 1988).


The response of the scleractinian coral Turbinaria reniformis to thermal stress depends on the nitrogen status of the coral holobiont

Eric BéraudFrançois GevaertCécile RottierChristine Ferrier-Pagès

Overall, results obtained in this study have shown that phosphate enrichment mainly affected the coral symbionts, by decreasing their C:P and N:P ratios, while increasing their carbon, nitrogen, and phos- phorus contents, as well as their specific growth rate, maximal photo- synthetic efficiency of the PSII, and rate of photosynthesis normalized to chlorophyll content. Phosphate enrichment also affected the skele- tal compartment, by increasing the skeletal growth and the P/Ca ratio. Conversely, few changes were observed in the animal host tissue.

The Godinot et al., 2011 citation leads to “Tissue and skeletal changes in the scleractinian coral Stylophora pistillata Esper 1797 under phosphate enrichment” is also interesting.

Here are the authors’ own highlights:

  • We examined P enrichment’s impact on calcification and tissue composition in corals.
  • We assessed a possible phosphorus limitation in symbiotic zooxanthellae.
  • Photosynthetic efficiency, CNP contents, and specific growth of symbionts increased.
  • Results indicated a phosphorus limitation of zooxanthellae growth in hospite.
  • Skeletal growth rates and phosphorus incorporation into the skeleton also increased.

We’re making a new post for that story now.  🙂

Is the coral-algae symbiosis really ‘mutually beneficial’ for the partners?

 Is the coral-algae symbiosis really ‘mutually beneficial’ for the partners? 

Scott Wooldridge
DOI: 10.1002/bies.200900182 · Source: PubMed

In terms of the demand for CO2(aq), an enlarged endosymbiont population increases the likelihood of CO2(aq) becoming a limiting internal substrate during periods of peak photosynthesis [18, 19]. Several environmental factors favour increased zooxanthellae densities (particularly on a per host cell basis), including: (i) elevated nutrient levels (e.g. dissolved inorganic nitrogen, DIN) in the surrounding sea water [20], elevation of the CO2 partial pressure (pCO2) in the surrounding sea water [21], and diffusive (i.e. branching) coral colony morphologies [22]. Experimental manipulations confirm the higher expulsion rate of zooxanthellae during periods of high irradiance in branching corals [23] and in corals exposed to DIN and pCO2 enrichment [24, 25].

Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata

Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata

Vianney Denis, Mireille M. M. Guillaume, Madeleine Goutx, Stéphane de Palmas, Julien Debreuil, Andrew C. Baker, Roxane K. Boonstra, J. Henrich Bruggemann
Research Article | published 30 Aug 2013 PLOS ONE

At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days), slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here.

Continue reading “Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata”