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Old 01/04/2016, 09:19 AM   #2516
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Join Date: Mar 2013
Posts: 59
Thinking about that led me to wonder if green phyto might be uniquely hostile towards dinos, as dinoflagellates horned in on a cozy duopoly: green algae and cyano basically ran the oceans for about a billion-and-a-quarter years before dinos evolved. Green algae outcompetes cyano for P at high N levels; cyano outcompetes green algae for N at high P levels. This was so effective at scouring nutrients out of NSW that dinos didn't even try to buck the system, but instead went with a radical, outside-the-box solution: heterotrophy. And because dinos were the first of the three main primary producers of the modern oceans to evolve, there was nothing to distract green algae from looking for ways to beat them down. That might explain this...

12/10/2015, 01:12 AM #2319
I've seen this green stuff on the image above punch a hole in my dino mat in a single day and then disappear the following day.
Cocos were the second of the modern triumvirate to evolve...

04/12/2015, 04:06 AM #941
I'd like to share something with you guys that I think is important.

First I'd like to introduce the Coccolithophores. (Emiliania Huxley)
They are about 5 micron and 5 times smaller than e.g. an Ostreopsis dinflagellate.
I noticed a bloom out of the coast here in Iceland at the same time I was jet again looking for a reason for my constant low calcium level. ...

A friend and myself simply can't get calcium levels to the SPS standard and they hover under 400 or lower if something happens to Ca production. ...

After my last water change the water column had a haze to it for a few days and I think that is possibly Coccolithophores and other calcareous algae.

They have a very short live span and use up a lot of calcium. Their armor falls of and slowly falls to the ocean floor, meanwhile they reflect light so well their blooms can be seen from space.
I can imagine they produce an organic mass that is like a dead fish in the tank at all times. Is this what fuels dinoflagellates?
04/12/2015, 06:56 AM #945
Here is Newbie Aquarists shot from yesterday.

Dinos, Cyano and Calcareous algae all going at the same time.
A 600 gallon tank makes the haze more visible.
His shots from last year are this way as well.
Cocos like high light levels and are adapted to compete effectively in very low nutrient environments -- their low requirements for Fe, Zn, and Cu keep them from being in direct competition with green algae for those micronutrients, which have low solubility in oxygenated NSW. In the wild, cocos dislike turbulence because they don't want to be churned down to lower depths where the light is dimmer, but they probably don't mind it so much in our tanks because there is no deep water and high flow conditions should help keep them suspended in the water column.

Like dinos, cocos are descended from predators, and there is evidence of mixotrophy in cocos, including consumption of dissolved organic carbon. Not all cocos make coccoliths -- some are "naked" and others, including Emiliania huxleyi, go through stages in which they lack a shell. This may facilitate heterotrophic feeding, which cocos apparently can't do when they're armored, though it can also result from cocos radically altering their biochemistry as blooms collapse to escape rapidly spreading pathogenic viruses.

E. huxleyi is the most common coco in the wild and thus of considerable ecological significance, and it is easily cultured and thus common in marine biology labs, as well, but it's unusual in some ways, such as its small size. As predation in aquatic environments is in large part a function of what any given predator can fit into its mouth, E. hux might be dino chow, and I have come across mention of E. hux blooms being surrounded by dinos and co-occuring with dinos... But to my enormous vexation, I don't have any hard evidence regarding the feeding behavior of O. ovata or O. lenticularis, which is externally very similar and often co-occurs with ovata in the wild. Micrographs of O. ovata (and also O. lenticularis) show that it lacks a classic physiological adaptation dinos use for opening up a large gap in their armor to ingest food and instead goes in the other direction, with a small opening between their armor plates. The other two ways dinos feed are with a pallium, which is a pseudopod or a sort of external stomach dinos use to enshroud and externally digest their prey, and a peduncle, which is a feeding tube dinos jab into their prey to suck out their insides. Peduncles are generally associated with heterotrophic dinos, but there are mixotrophic species with peduncles (though none of them are known to prey on large animals like fish as heterotrophic dinos do). Pallium feeders can take prey larger than the dinos themselves and can grow very quickly as a result. Either approach could be effective on cocos, but if I were a betting man, I'd put my money on O. ovata being a pallium feeder -- though I'd also lay a side bet that ostis have both a peduncle and a pallium, just because that seems like the option of maximum evilness.

Regardless of whether or not dinos eat cocos, their co-occurrence would make sense, as both are adapted to thrive in low nutrient environments but wouldn't be in competition for the same ecological niche, as cocos can efficiently absorb nutrients from the water column, which it turns out dinos suck at. One computer model of marine primary production predicted over and over that, given the measured abilities of dinos to absorb nutrients, other primary producers should outcompete them and rapidly drive dinoflagellates into extinction -- no amount of tweaking the model, such as by reducing dinos' appeal to grazers, could save them. But the model didn't include mixotrophy, suggesting that dinos are profoundly dependent on heterotrophic feeding to get the nutrients they need for phototrophic growth.

Originally Posted by The role of functional traits and trade-offs in structuring phytoplankton communities: scaling from cellular to ecosystem level
Marine dinoflagellates have significantly lower maximum carbon-specific nutrient uptake rates than diatoms, and significantly higher half-saturation constants for nitrate uptake and relatively low maximum growth rates (although some dinoflagellates are capable of rapid growth), thus being poor competitors for nitrate. It is likely that such "dirty tricks" as the ability to feed heterotrophically and migrate in the water column allows dinoflagellates to persist, despite the relatively non-competitive parameters for nitrogen uptake and growth.

12/31/2014, 05:14 PM #604
Dinoflagellates are so delicate and easy to kill...
In this battle, the fundamental problem we face as reefers is that dinos and corals essentially have the same business model. They're both mixotrophs and thus thrive in oligotrophic conditions. The difference seems to be organic carbon... My interpretation of the evidence is that corals prefer a low N, low P, low C environment, while dinos are into a low N, low P, high C environment. This might be further broken down to specify that corals prefer low-ish levels of labile DOC and recalcitrant organic carbon, but high levels of particulate organic carbon (pods and other tasty morsels the corals can capture and eat), while dinos prefer high levels of labile DOC (which they make), high levels of recalcitrant organic carbon (which they need for their bacteria farms), and high levels of particulate organic carbon (which in this case would be the bacteria and other organisms of the dinoflagellate holobiont, stuff the dinos can eat or kill with their toxins and feed to their bacteria, and I guess also the dinos themselves).

I would go so far as to speculate that the difference between a healthy reef dominated by corals (or a broken reef dominated by algae) and one dominated by benthic dinos could come down to a phase shift driven by copiotrophy... As noted earlier, eutrophy tends to favor flavobacteria from among the Bacteroidetes, possibly because they're geared to consume the remains of green algae. But ostis are partnered with different bacteria that need different conditions -- not the decaying remains of algae, but an environment enriched in the degraded, recalcitrant remains of animal proteins. Or as we hobbyists would put it, detritus.

It's tempting to connect this to the Mesozoic Marine Revolution, an extended arms race between predators and prey that recent research shows began in the early Triassic, after the oceans recovered from the devastating end Permian mass extinction that wiped out >96% of known marine species and >70% of terrestrial species 252 million years ago. The MMR doomed the surviving benthic fauna of the Paleozoic, which was characterized by relatively dense populations of sessile, armored creatures, as creatures able to crack them open evolved after the end Permian extinction, eventually driving the survivors underground or forcing them to evolve mobility. The first dino cysts appear in the fossil record 228 million years ago, and here are a couple more fun science facts: the ancestors of symbiodinium dinos were among the earliest lineages to emerge, and corals experienced a burst of speciation in the Triassic that followed the evolution of dinos. Good bet at least some of those early dinos were mixotrophic, and the team-up with corals happened pretty quickly (...most likely, some corals already had photosynthetic endosymbiotes -- either cyano or algae -- that were poorly suited to the oligotrophic reef environment, so they would have been happy to switch over to them thar newfangled dinoflagellates). Certainly, dinos show up just as the first waves of New & Improved predators were consuming mass quantities of the immobile Paleozoic benthic fauna and pooping out their remains, and judging by where their fossilized cysts were found, dinos were on Triassic reefs during a time when the reef sands would plausibly have been enriched in old, degraded, recalcitrant animal proteins... That would explain their high quotas for trace metals.

Though on the other hand, so would evolving in a Canfield ocean following a mass extinction, as widespread euxinia would raise the availability of trace nutrients with low solubility in oxygenated seawater (most notably iron, but also zinc and copper) and a Canfield ocean is dominated by bacteria and thus would seem to be the ideal environment for a marine eukaryote to evolve that specializes in eating bacteria and stealing their DNA. But the cyano/green algae duopoly held up through a billion-plus years' worth of euxinic episodes without dinos popping up... What changed? If primary producers preserve in their nutritional habits evidence of the ecological circumstances in which they first evolved, then it's reasonable to suppose that a primary producer adapted to thrive not in eutrophic but copiotrophic conditions evolved during a period characterized by copiotrophy, so as I said, it's hard to resist connecting the emergence of dinos to the Mesozoic Marine Revolution.

But either scenario would posit an incomplete food web that eases top-down grazing pressure on primary producers, allowing the drawdown of macronutrients until N and P are zeroed out, and reduces the efficiency of the CUC, resulting in the increased availability of organic C pumping up the bacteria population. Or looked at another way: the conditions that seem to open the door to a dino bloom in our fish tanks. And once toxic dinoflagellates break out into a bloom, dino-friendly bacteria that thrive in copiotrophic conditions help them kill stuff, which of course makes conditions even more copiotrophic...

Just as coral-friendly bacteria reinforce conditions amenable to coral and algae-friendly bacteria help algae take over reefs, dino-friendly bacteria want to remake the ecosystem to suit dinos. Quiet_Ivy's tank and others may be pointing us at O. ovata's endgame: a collapsed "hypercopiotrophic" food web dominated by dinos and their bacteria farms, recreating the landscape of death that the first dinos evolved to exploit.

It seems that benthic dinos and corals have diametrically opposed philosophies about how to make the most of mixotrophy in oligotrophic reef environments. Dinos are selfish and want it all, while corals are into enlightened self-interest. Rather than take a bigger slice of the pie, corals make the pie bigger.

Or so it looks to me, at any rate, so I took my cue from corals and wrote up this massive wall of text. I'm no scientist, nor do I have any education in microbiology -- for that matter, the last biology class I took was freshman year of high school -- meaning that's about as far as I can take this on my own. Time to get some more minds in on this to look for what I overlooked, to identify connections to what we see in our tanks, and to try to make the pie bigger.

In closing, gaze not into the dino bloom, for the dinos gaze also into you!



The Coral Probiotic Hypothesis

Bacteria Associated with Toxic Clonal Cultures of the Dinoflagellate Ostreopsis lenticularis

Ecology of marine Bacteroidetes: a comparative genomics approach

Phylogenetic and functional diversity of the cultivable bacterial community associated with the paralytic shellfish poisoning dinoflagellate Gymnodinium catenatum

The effect of quorum-sensing blockers on the formation of marine microbial communities and larval attachment

Ostreopsis cf. ovata (Dinophyta) bloom in an equatorial island of the Atlantic Ocean

Regulation of microbial populations by coral surface mucus and mucus-associated bacteria

Antimicrobial properties of resident coral mucus bacteria of Oculina patagonica

Bacteria Associated with Toxic Clonal Cultures of the Dinoflagellate Ostreopsis lenticularis

Production of Antibacterial Compounds and Biofilm Formation by Roseobacter Species Are Influenced by Culture Conditions

Diversity and dynamics of bacterial communities in early life stages of the Caribbean coral Porites astreoides

Microbial community composition of black band disease on the coral host Siderastrea siderea from three regions of the wider Caribbean

Microbial Communities in the Surface Mucopolysaccharide Layer and the Black Band Microbial Mat of Black Band-Diseased Siderastrea siderea

Identification and enumeration of bacteria assimilating dimethylsulfoniopropionate (DMSP) in the North Atlantic and Gulf of Mexico

Algicidial Bacteria from fish culture areas in Bolinao, Pangasinan, Northern Philippines

Organic matter release by Red Sea coral reef organisms - potential effects on microbial activity and in situ O2 availability

Induction of Larval Settlement in the Reef Coral Porites astreoides by a Cultivated Marine Roseobacter Strain

Unseen players shape benthic competition on coral reefs

Advanced Aquarist feature article Total Organic Carbon (TOC) and the Reef Aquarium: an Initial Survey, Part I

Influence of coral and algal exudates on microbially mediated reef metabolism

abstract of Microbial photosynthesis in coral reef sediments (Heron Reef, Australia)

Sponge waste that fuels marine oligotrophic food webs: a re-assessment of its origin and nature

Natural Diet of Coral-Excavating Sponges Consists Mainly of Dissolved Organic Carbon (DOC)

Endoscopic exploration of Red Sea coral reefs reveals dense populations of cavity-dwelling sponges
see page 17 of Feeding ecology of coral reef sponges

The role of functional traits and trade-offs in structuring phytoplankton communities: scaling from cellular to ecosystem level

Toward a stoichiometric framework for evolutionary biology

Health of Coral Reefs: Measuring Benthic Indicator Groups and Calculating Tipping Points


Recommended reading

Black reefs: iron-induced phase shifts on coral reefs

Cataloguing Diseases and Pests in Captive Corals

Communities of coral reef cavities in Jordan, Gulf of Aqaba
see page 40 of Feeding ecology of coral reef sponges

Coral-associated micro-organisms and their roles in promoting coral health and thwarting diseases

The coral core microbiome identifies rare bacterial taxa as ubiquitous endosymbionts

Coral Disease, Environmental Drivers, and the Balance Between Coral and Microbial Associates

Coral mucus-associated bacterial communities from natural and aquarium environments

Coral Reef Bacterial Communities

Herbivory, Nutrients, Stochastic Events, and Relative Dominances of Benthic Indicator Groups on Coral Reefs: A Review and Recommendations

How Microbial Community Composition Regulates Coral Disease Development

Mass Mortality of Porites Corals on Northern Persian Gulf Reefs due to Sediment-Microbial Interactions

Master recyclers: features and functions of bacteria associated with phytoplankton blooms

Nutritional ecology of nominally herbivorous fishes on coral reefs

The Role of Microorganisms in Coral Health, Disease, and Evolution

Viruses of reef-building scleractinian corals

What we can learn from sushi: a review on seaweed–bacterial associations


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