Skimmer Time

[Uncle99]

When my phosphate gets below 0.02ppm with Nitrate at 10ppm, Cyano returns.

When I increase phosphate to 0.08-.1ppm they disappear.

 

[Timfish]

Reffering to the OP I'd toss the skimmer. It doesn't matter where you look research is showing whether it's sustainable farming or sustaining our own physical and mental health the proper microbial balance is essential. Feldman, et al, showed skimmers skew the bacterial counts and significantly reduce them as well. hey also showed skimmers don't remove as much as we thought. Additionally, de Goeij showed cryptic zones with their cryptic sponges remove labile DOC 1000X faster than bacterioplankton. Skimmers also do not remove the hydrophylic compounds that promote shifts in the coral holobiont to heterotrophic that draw down oxygen levels in the coral mucus suffocating them and potentially promoting pathogenic microbes (See Rower's book "Coral Reefs in the Microbial Seas" or his video linked below). Since additional discussion has looked at nutrients I'd point out we need to be looking at total nitrogen and total phosphorus not just the inorganic forms nitrate and PO4. There are some additional links below for those intersted in reading more. And for those wondering where cyano (and corals if necessary, see the link to diazotrophs) they have the enzymes to convert N2, free nitrogen, into nitrates. There's also some links on algae

Forest Rohwer "Coral Reefs in the Microbial Seas"


Changing Seas - Mysterious Microbes


Nitrogen cycling in hte coral holobiont


BActeria and Sponges


Richard Ross What's up with phosphate"



Ammonium Uptake by Symbiotic and Aposymbiotic Reef Corals
http://www.ingentaconnect.com/content/umrsmas/bullmar/1979/00000029/00000004/art00011
Amino acids a source of nitrogen for corals
https://journals.biologists.com/jeb...2/Uptake-of-dissolved-free-amino-acids-by-the
Urea a source of nitrogen for corals
https://www.sciencedirect.com/science/article/abs/pii/S0022098105005538
Diazotrpophs a source of nitrogen for corals
https://pubmed.ncbi.nlm.nih.gov/27335448/
Context Dependant Effects of Nutrient Loading on the Coral-Algal Mutualism
https://www.researchgate.net/public...nutrient_loading_on_the_coral-algal_mutualism


https://www.cambridge.org/core/jour...reef-corals/AFB1CF4CB68823BD13AD254623FD3C7C#An Experimental Mesocosm for Longterm Studies of Reef Corals

Phosphate Deficiency:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
https://www.nature.com/articles/nclimate1661
Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full
Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via=ihub
Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach
https://www.sciencedirect.com/science/article/pii/S0022098111004588
High phosphate uptake requirements of the scleractinian coral Stylophora pistillata
http://jeb.biologists.org/content/214/16/2749.full
Phosphorus metabolism of reef organisms with algal symbionts
https://esajournals.onlinelibrary.w...98e60zfBEvx5IcIVGhmlpUYmzIJuqUNVm0sG8_0vth6lq
https://therichross.com/skeptical-reefkeeping-ix-test-kits-chasing-numbers-and-phosphate/
Sponge symbionts and the marine P cycle
https://www.pnas.org/content/112/14/4191
Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges
https://www.pnas.org/content/112/14/4381
Indirect effects of algae on coral: algae‐mediated, microbe‐induced coral mortality
Coral seperated from algae with a .02 µm filter die. Treatment with aampicillan prevents death.
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

Because sponges are essential players in the carbon, nitrogen and phosphorus cycle(s) on reefs here's some links to research done with them.

Element cycling on tropical coral reefs.
This is Jasper de Geoij's ground breaking research on reef sponges. (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
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
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
And since we're discussing favorable and not so favorable bacteria here's a paper looking at how different corals and polyps are influencing the bacteria in the water column.
Aura-biomes are present in the water layer above coral reef benthic macro-organisms
https://www.ncbi.nlm.nih.gov/pubmed/28828261