Yeah, it doesn't help new research only adds to the complexity of reef ecosystems including showing there's not only species specific but
genotype specific stuff. :beaming-face-with-smiling-eyes: I started really digging into DOC a decade ago after posts about labile and refractory DOC to help understand better what's happening in my systems. About that time I stumbled across Rower's book which is still the best introduction I've found.
Of course, but the DOC corals and algae release are differentially promoting the microbiomes in the water. (My thinking about microbial stuff was shifted in a conversation with the director of infectious diseases of a local hospital in '97 but PaulB certainly deserves kudo's for bringing up the subject a long time ago on some of the forums.) Water changes will lower the number of microbes detrimental to corals along with detrimental DOC. Ideally, corals will be able to replenish more of the beneficial stuff in the water than the alage does the detrimental stuff. Also, coral DOC largely stays in the coral's mucus layer hopefully promoting the beneficial bacteria that are a critical components to coral immune systems whereas algae DOC promotes increased microbial loads in the water allowing microbes to utilize refractory DOC as a food source not normally available. Surprisingly, one counter intuitive finding is the increase algae DOC production results in lower and in extreme situations no DOC, labile or refractory, in a reef system (Andreas Haas, presetation to Austin Reef Club frag swap, 2015). Here's some of the links I've collected over the years:
These first five do an excellent job of introducing the subject of DOC, corals, algae and microbes and is probably all anyone planning on keeping a reef going for decades needs. Rest is mostly for obsesive types like me:
Total Organic Carbon Pt 1
http://www.advancedaquarist.com/2008/8/aafeature3
Total Organic Carbon Pt 2
http://www.advancedaquarist.com/2008/9/aafeature2
Bacterial Counts in Reef Aquarium Water
https://reefs.com/magazine/bacteria...ing-and-granular-activated-carbon-filtration/
"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems
Here's a data bomb on microbes and doc and sponges. If it seems overwhelming keep in mind I've taken over 10 years to collect the links so don't feel you need to read or watch them all by the end of the month. Some have to be purchased to read the entire paper but the abstract will have some essential points. (And don't think I've bought all the ones needing purchase. ;) )
Changing Seas - Mysterious Microbes
Nitrogen cycling in hte coral holobiont
BActeria and Sponges
Maintenance of Coral Reef Health (refferences at the end)
Indirect effects of algae on coral: algae‐mediated, microbe‐induced coral mortality
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2006.00937.x
Influence of coral and algal exudates on microbially mediated reef metabolism.
Coral DOC improves oxygen (autotrophy), algae DOC reduces oxygen (heterotrophy).
https://peerj.com/articles/108/?utm_source=TrendMD&utm_campaign=PeerJ_TrendMD_0&utm_medium=TrendMD
Role of elevated organic carbon levels and microbial activity in coral mortality
http://www.int-res.com/articles/meps2006/314/m314p119.pdf
Effects of Coral Reef Benthic Primary Producers on Dissolved Organic Carbon and Microbial Activity
Algae releases significantly more DOC into the water than coral.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0027973
Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species.
Starch and sugars (doc) caused coral death but not high nitrates, phosphates or ammonium.
http://www.int-res.com/articles/meps2005/294/m294p173.pdf
Visualization of oxygen distribution patterns caused by coral and algae
https://peerj.com/articles/106/
Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
Exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719127/
Microbial ecology: Algae feed a shift on coral reefs
https://www.nature.com/articles/nmicrobiol201661
Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages.
https://www.ncbi.nlm.nih.gov/pubmed/23303369
Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching
https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13695
Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution
(here's an argument for maintaining heavy fish loads if you're carbon dosing)
https://www.sciencedirect.com/science/article/pii/S0166445X19307192
Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton
https://www.nature.com/articles/ismej2017142
Unseen players shape benthic competition on coral reefs.
https://www.ncbi.nlm.nih.gov/pubmed/22944243
Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance.
https://www.ncbi.nlm.nih.gov/pubmed/27795310
Macroalgae decrease growth and alter microbial community structure of the reef-building coral, Porites astreoides.
https://www.ncbi.nlm.nih.gov/pubmed/22957055
Macroalgal extracts induce bacterial assemblage shifts and sublethal tissue stress in Caribbean corals.
https://www.ncbi.nlm.nih.gov/pubmed/23028648
Biophysical and physiological processes causing oxygen loss from coral reefs.
https://elifesciences.org/articles/49114.pdf
Global microbialization of coral reefs
DDAM Proven
https://www.nature.com/articles/nmicrobiol201642
Coral Reef Microorganisms in a Changing Climate, Fig 3
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096749/figure/fig3/
Ecosystem Microbiology of Coral Reefs: Linking Genomic, Metabolomic, and Biogeochemical Dynamics from Animal Symbioses to Reefscape Processes
https://msystems.asm.org/content/msys/3/2/e00162-17.full.pdf
Here's stuff on sponges which I think have been badly overlooked as sponges are integral to processing DOC in reef ecosystems. Steve Tyree certainly deserves kudos for promoting them. Sponges are essential recyclers in reef systems but are a double edge sword as they process DOC from corals differently than algae. To some extent they are protecting aquarists who carbon dose from the negative effects of excess labile DOC but research has shown as reef ecosystems are impacted by stressors they can form a positive feedback loop favoring algae hastening phase shifts detrimental to corals.
Element cycling on tropical coral reefs.
This is Jasper de Geoij's ground breaking research on reef sponge finding some species process labile DOC 1000X faster than bacterioplankton. (The introduction is in Dutch but the content is in English.)
https://www.rug.nl/research/portal/files/14555035/13completethesis.pdf
Sponge symbionts and the marine P cycle
https://www.pnas.org/content/112/14/4191
Processing of Naturally Sourced Macroalgal- and Coral-Dissolved Organic Matter (DOM) by High and Low Microbial Abundance Encrusting Sponges
https://www.frontiersin.org/article...nalName=Frontiers_in_Marine_Science&id=640583
Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges
https://www.pnas.org/content/112/14/4381
Differential recycling of coral and algal dissolved organic matter via the sponge loop.
Sponges treat DOC from algae differently than DOC from corals
https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.12758
A Vicious Circle? Altered Carbon and Nutrient Cycling May Explain the Low Resilience of Caribbean Coral Reefs
https://academic.oup.com/bioscience/article/66/6/470/2754308
Surviving in a Marine Desert The Sponge Loop Retains Resources Within Coral Reefs
Dissolved organic carbon and nitrogen are quickly processed by sponges and released back into the reef food web in hours as carbon and nitrogen rich detritus.
https://www.researchgate.net/publication/279061640_2013_deGoeij_Science_Sponge_loop
Natural Diet of Coral-Excavating Sponges Consists Mainly of Dissolved Organic Carbon (DOC)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3934968/
The Role of Marine Sponges in Carbon and Nitrogen Cycles of COral Reefs and Nearshore Environments.
https://search.proquest.com/openvie...9d1e5/1?pq-origsite=gscholar&cbl=18750&diss=y
BActeria and Sponges
A Vicious Circle? Altered Carbon and Nutrient Cycling May Explain the Low Resilience of Caribbean Coral Reefs
https://academic.oup.com/bioscience/article/66/6/470/2754308