Bioindicators

[Subsea]

After 55 years of reefing, I don’t test much; I observe. I am fascinated with the ebb of flow of our ecosystems. As I peer into their micro world, it amazes me as to the complexity of biofiltration. In recalling a verse from a Beatles song “With a little help from our friends”, I lift up the flame scallop and Caulerpa Paspoides:

Flame Scallops are quite sensitive to water quality. They are the first to let me know when things are off.

Caulerpa Paspoides is my bioindicator for inorganic nutrients and trace minerals. At the moment, the slight increasing of white along the ends of some fronds tells me that nitrogen is limited. This white is a precursor to the seaweed going sexual.

My interpretation of a Caribbean lagoon.

 

[rayadog]

How often do you have to replace your test kits? I didn’t think Flame scallops had a great natural longevity as I’ve read.

 

[Subsea]

How often do you have to replace your test kits? I didn’t think Flame scallops had a great natural longevity as I’ve read.

I have unopened test kits with expiation dates.

With flame scallops, I get about 2 years, then they expire.

 

[BryanM]

I don't know if I will ever get this much experience where I can just tell whats happening by looking at the tank, but it is aspirational!

 

[Subsea]

I don't know if I will ever get this much experience where I can just tell whats happening by looking at the tank, but it is aspirational!

“Nobel Prize-winning Danish physicist Niels Bohr. He famously defined an expert as "a person who has made all the mistakes that can be made in a very narrow field". [1, 2, 3]
Bohr used this definition to emphasize that true expertise and mastery are not achieved by simply knowing everything perfectly. Instead, experts gain their deep practical knowledge through trial, error, and overcoming every possible failure within their specific subject. [1]”

Bryon,
It helps that my corals are softies and don’t require steady state conditions. I focus on diverse food webs using diver collected live rock, cryptic refugium, and reverse flow UG filter. For me, I seek balancing livestock that compliments the marine community with function of behavior and ascetics.

 

[EnterName]

Caulerpa Paspoides is my bioindicator for inorganic nutrients and trace minerals. At the moment, the slight increasing of white along the ends of some fronds tells me that nitrogen is limited. This white is a precursor to the seaweed going sexual.

Is nitrogen limitation actually the trigger for C. Paspoides starting sexual reproduction?

I know that the whitening indicates the upcoming release of gametes, as this is well documented, but I'm not able to find anything on a nitrogen limitation triggering gametogenesis.

 

[Subsea]

Is nitrogen limitation actually the trigger for C. Paspoides starting sexual reproduction?

I know that the whitening indicates the upcoming release of gametes, as this is well documented, but I'm not able to find anything on a nitrogen limitation triggering gametogenesis.

“Releasing gametes” is the technical description of “going sexual”.

There are differrent degrees of going sexual. My first experience entailed Caulerpa Prolifera & Caulerpa Paspoides growing under 1000W MH over 150G tank. Both were growing fast and water clarity was stellar when I went to bed. In the morning, I could not see the back glass. It didn’t take an ICP test in the morning to tell me what happened and why. I continue operating my Caribbean lagoon in a similar fashion, except the lights are much less.

 

[EnterName]

Is nitrogen limitation actually the trigger for C. Paspoides starting sexual reproduction?

I know that the whitening indicates the upcoming release of gametes, as this is well documented, but I'm not able to find anything on a nitrogen limitation triggering gametogenesis.

“Releasing gametes” is the technical description of “going sexual”.

Yes, I know.
I was asking if low nitrogen triggers this because you said you use this as an indicator. I might have phrased my question weird, sorry.

 

[Subsea]

Yes, I know.
I was asking if low nitrogen triggers this because you said you use this as an indicator. I might have phrased my question weird, sorry.

In my experiences, when fast growing seaweeds become nitrogen limited, they deteriorate and release gamets as a survival technique.

PS: I consistently add ammonia to maintain nitrogen in this display.

 

[EnterName]

Yes, I know.
I was asking if low nitrogen triggers this because you said you use this as an indicator. I might have phrased my question weird, sorry.

In my experiences, when fast growing seaweeds become nitrogen limited, they deteriorate and release gamets as a survival technique.

PS: I consistently add ammonia to maintain nitrogen in this display.

Hm okay, I mean I started ammonia dosing a while ago myself but even with nitrate levels below 1ppm I wasn't able to tell if I actually had a nitrogen limitation, as natural sea levels are far lower. Maybe it's not a survival technique, but they are actually happy that now the nitrogen supply fits their natural environment which optimizes the reproduction success rate?

I doubt this applies to caulerpa, but some other organisms also start spawning depending on the moon phase as having all organisms spawn at the same time increases the chance of actually fertilizing something. Maybe dropping below a nitrate threshold is this trigger point for them even though they are still far from being limited by nitrogen.

 

[Subsea]

so, if your test kits don’t measure any inorganic nitrate, then how do you determine if the amount of ammonia dosed is sufficient for bioload.

In this 55G seaweed growout tank, I dose 20ml of ammonia twice a day. When tested by LFS, both phosphate & nitrate show below detectable limits. In the case of corals, it’s a different game. LPS, SPS & NPS use POC (Particulate Organic Carbon).

 

[Subsea]

Is nitrogen limitation actually the trigger for C. Paspoides starting sexual reproduction?

I know that the whitening indicates the upcoming release of gametes, as this is well documented, but I'm not able to find anything on a nitrogen limitation triggering gametogenesis.

@EnterName
It depends on how you word your question. I asked this:

“nitrogen limitation triggering gametogenesis in marine seaweeds”

And I got this:

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2019.00618/full
with this summary:

Overview

Nitrogen limitation acts as an environmental stress cue that triggers the transition from vegetative growth to gametogenesis (sexual reproduction) and sporulation in many marine macroalgae, often interacting with light, temperature, and bacterial signaling

 

[Australian_Reef]

“Nobel Prize-winning Danish physicist Niels Bohr. He famously defined an expert as "a person who has made all the mistakes that can be made in a very narrow field". [1, 2, 3]
Bohr used this definition to emphasize that true expertise and mastery are not achieved by simply knowing everything perfectly. Instead, experts gain their deep practical knowledge through trial, error, and overcoming every possible failure within their specific subject. [1]”

Bryon,
It helps that my corals are softies and don’t require steady state conditions. I focus on diverse food webs using diver collected live rock, cryptic refugium, and reverse flow UG filter. For me, I seek balancing livestock that compliments the marine community with function of behavior and ascetics.

But you can’t systematically share feelings. Experience is nothing if it you can’t quantify, explain and pass on.

 

[Subsea]

But you can’t systematically share feelings. Experience is nothing if it you can’t quantify, explain and pass on.

Thread title is bioindicators. I list certain bioindicators and detail my explanation.

Not sure what “systematically share feelings” have to do with what I posted.

 

[EnterName]

Is nitrogen limitation actually the trigger for C. Paspoides starting sexual reproduction?

I know that the whitening indicates the upcoming release of gametes, as this is well documented, but I'm not able to find anything on a nitrogen limitation triggering gametogenesis.

@EnterName
It depends on how you word your question. I asked this:

“nitrogen limitation triggering gametogenesis in marine seaweeds”

And I got this:

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2019.00618/full
with this summary:

Overview

Nitrogen limitation acts as an environmental stress cue that triggers the transition from vegetative growth to gametogenesis (sexual reproduction) and sporulation in many marine macroalgae, often interacting with light, temperature, and bacterial signaling

I mean, it totally makes sense from a survival perspective, and I'm certainly not saying you should change anything at all if it is working for your tank!

I'm just wondering how probable it is to actually reach nitrogen levels so low that an algae's survival response would be triggered as it can no longer take up enough nitrogen to sustain itself.

I'm not asking to doubt your assessment, I'm genuinely asking because nitrate levels in natural reefs can be extremely low without causing a mass starvation. I've had nitrate levels below 0ppm for a long time and still managed to keep corals alive without feeding them. This makes me wonder if my current approach of dosing ammonia to keep nitrate above 0ppm is even necessary.

 

[Subsea]

I mean, it totally makes sense from a survival perspective, and I'm certainly not saying you should change anything at all if it is working for your tank!

I'm just wondering how probable it is to actually reach nitrogen levels so low that an algae's survival response would be triggered as it can no longer take up enough nitrogen to sustain itself.

I'm not asking to doubt your assessment, I'm genuinely asking because nitrate levels in natural reefs can be extremely low without causing a mass starvation. I've had nitrate levels below 0ppm for a long time and still managed to keep corals alive without feeding them. This makes me wonder if my current approach of dosing ammonia to keep nitrate above 0ppm is even necessary.

First, it’s not just my observation/assestment. I linked a peer reviewed aquaculture study.

“I'm just wondering how probable it is to actually reach nitrogen levels so low that an algae's survival response would be triggered as it can no longer take up enough nitrogen to sustain itself.”

Also, I see threads on this website listing macro algae went sexual.

I have spoken with marine biology graduate student who have witnessed large areas of seaweed self destructing with new growth following using nutrients from what disintegrated.

“This makes me wonder if my current approach of dosing ammonia to keep nitrate above 0ppm is even necessaryg”

Apples & oranges. Seaweed use inorganic nitrogen. Corals are more opportunistic and they use inorganic & organic nutrients, which includes POC.

 

[Subsea]

One other observed bioindicator of Caulerpa Paspoides during daylight hours was white substance oozing from main stem which had doubled in diameter. I pruned off that section of seaweed and dosed tank with ammonia.

 

[Subsea]

“I'm not asking to doubt your assessment, I'm genuinely asking because nitrate levels in natural reefs can be extremely low without causing a mass starvation. I've had nitrate levels below 0ppm for a long time and still managed to keep corals alive without feeding them. This makes me wonder if my current approach of dosing ammonia to keep nitrate above 0ppm is even necessary.”

@EnterName
Let’s park here at ZERO.
When test results show 0, that means the concentration is below the sensitivity of the test. When I send water and seaweed to regional Agriculture lab, the readings for Copper & Zinc showed zero in both ground water and circulating water in outdoor mariculture tanks.

However, Gracilaria Hayi showed 2ppm of Cu & 4ppm of Zn. The lower detection limit was 1ppb.

One takeaway is that seaweed absorbs heavy metals.

“asking because nitrate levels in natural reefs can be extremely low without causing a mass starvation”

Let’s park here:
Mass starvation of what? Remember apples & oranges. I am talking about seaweeds & I assume you are talking about coral. So, let’s talk about coral and certain Cyanobacteria within coral biomass that perform nitrogen fixation (converting N2 into NH3) when nitrogen is limited in bulk water.


“Nitrogen fixation in coral biomass is the process where specialized microbes convert inert atmospheric nitrogen gas into usable nutrients that support coral growth. This vital activity happens within the coral's tissue, mucus, and skeleton, providing essential food for both the coral animal and its microscopic algae partners. [1, 2]”