Toxicity of nitrate isotopes discovered!

Boomer · 04-01-2005, 01:10 AM

I just found this article that many reefers may find interesting. Note especially the conclusions at the end of the abstract:

Toxicity of 15N and 18O isotopes of nitrate in seawater. Lehnenn, Molz F.; Sidnan, Daniel P.; Barry, Willard T. Department of Marine Chemistry, Florida University, Coral Gables, FL, USA. Marine Chemistry Monthly, April 1, 2005, 1-55.

Abstract

We report 15N/14N and 18O/16O ratios of nitrate in toxicity tests involving benthic chamber incubations in the continental shelf sediments of the Great Barrier Reef to deconvolve the effects of nitrate isotope toxicity. Previous researchers have reported little toxicity due to nitrate, but our studies show greatly increased toxicity for the 15N/18O isotope of nitrate. Ests. of toxicity from benthic flux stoichiometry are 0.9-2.5 mmol N/m2-day. Between 46 and 100% of the total toxicity can be explained by nitrate istotopes with 15N. In general and independent of the toxicity and the fraction of remineralized N being tested, nitrate 15N/14N and 18O/16O ratios do not change significantly with progressive nitrate depletion in corals. A lack of change in nitrate 15N/14N could be due to either the lack of effective N isotope fractionation assocd. with nitrate toxicity, or the balancing of an 18O isotope effect by the addn. of low-15N/14N nitrate from nitrification. However, the lack of an increase in nitrate 18O/16O indicates that the isotopic fractionation specifically assocd. with toxicity is, in fact, negligible. The coupled N and O isotope measurements also indicate that there is great concern in the gross efflux of 15N-depleted nitrate from nitrification, leading to the conclusion that scientists keeping organisms in closed systems, such as aquaria, are likely slowly killing them with 15N isotopes.

__________________
Randy Holmes-Farley
Want to talk chemistry? Try the Reef Chemistry Forum at Reef Central

gussy · 04-01-2005, 01:35 AM

Umm...what does it say?

rckmtl · 04-01-2005, 02:07 AM

oooh, oooh, let me quess!

I'm gonna guess that what it is saying is that, in a closed system there are not the same amounts/ratios of all the different ions that contribute to the denitrification process as there are in a natural enviroment(the ocean). As a result, the'bad' ions aren't really detoxified the way people think they are, but are in fact slowly building up to lethal levels.

I'm I right, or am I totally off course??????

either way, I do not agree with their conclusion, becuase the denitrification process in aquaria is only to keep things stabilized in between water changes. Then you do one and out goes a big chunk of all the bad stuff.

If the very generalized statment at the end were 100% true then everyones fish would die off after 5 or 10 years, and obviously there are many healthy animals that have been in captivity longer then that.

Brucey · 04-01-2005, 06:35 AM

Quote:

Originally Posted by rckmtl

either way, I do not agree with their conclusion, becuase the denitrification process in aquaria is only to keep things stabilized in between water changes. Then you do one and out goes a big chunk of all the bad stuff

Well, Boomer is always talking about stuff I don't understand but I still love him for it. Your comments make an interesting point in relation to the article, in that . . . . I know of closed systems where there has not been a water change done for over 2 years. This is at a LFS with a heavily stocked tank (SPS and fish) . . . and he counterbalances the water changes with the addition of additives . . . . not the way I'd like to run a system but it works for him.

Brucey

Woodstock · 04-01-2005, 09:10 AM

My interpretation after only one cup of coffee..... NitrAtes are very harmful to our tank inhabitants and at only 15N/Isotope the corals are slowly dieing

15N/Isotope = _________? (ppm nitrAtes)

Boomer · 04-01-2005, 12:14 PM

Ellen

That is about it and your option is about the same as mine

ions

Lets explain that. Nitrate is NO3- an ion, know as a anion as it has a negative charge . It has an overhaul charge of -1. Many atoms, such as N, O, Ca, Mg may loose or gain an electron and become an ion. However, those same ions may have lost or gained a neutron in the nucleus and these are know as isotopes. Oxygen often comes as either isotope 18 or 16. Meaning the oxygen has either 18 or 16 neutrons. Same for the Nitrogen, 14 or 15 neutrons. These extra neutrons just change the weight of the atom. Some isotopes are more common than others and some are more toxic. These researchers are being very specific as to what isotopes make up the nitrate ion. 15 N Nitrate is the highest concentration of the two and it is the 15-Nitrate in their study that is accumulating the most, thus the accumulation of 15-Nitrate may bring about nitrate toxicity in close systems like aquariums.

Woody

3 ppm 15N nitrate is the same as 3 ppm 14N Nitrate. Our trest kits don't know the difference between the two. 3 ppm Nitrate will be some of both, 14N or 15N. Isotopes are pretty much a geologic age thing. If you had a tank a million years ago the ratios would be different for the 14 and 15N. It is like the oxygen (O2) you breath, some will 16-O2 and some will be 18-O2

angnak · 04-01-2005, 01:10 PM

HMMMM.... Yes doctor I concur.

Very interesting and I also think we are taking out the bad with water changes.

Travelin Reef · 04-01-2005, 01:30 PM

so does all of this still mean we can't put a screen door in a submarine?

Boomer · 04-01-2005, 01:41 PM

Yes Trav, that is correct

rckmtl · 04-01-2005, 04:38 PM

Quote:

Originally Posted by Boomer

ions

Lets explain that. Nitrate is NO3- an ion, know as a anion as it has a negative charge . It has an overhaul charge of -1. Many atoms, such as N, O, Ca, Mg may loose or gain an electron and become an ion. However, those same ions may have lost or gained a neutron in the nucleus and these are know as isotopes. Oxygen often comes as either isotope 18 or 16. Meaning the oxygen has either 18 or 16 neutrons. Same for the Nitrogen, 14 or 15 neutrons. These extra neutrons just change the weight of the atom. Some isotopes are more common than others and some are more toxic. These researchers are being very specific as to what isotopes make up the nitrate ion. 15 N Nitrate is the highest concentration of the two and it is the 15-Nitrate in their study that is accumulating the most, thus the accumulation of 15-Nitrate may bring about nitrate toxicity in close systems like aquariums.

Thank you for the clarification. It has been like 9yrs since high school chem class. Stuff like this is great though cuz you go to read about some reef stuff and you get all these mini refresher courses!

jhnrb · 04-01-2005, 10:19 PM

Thanks for the article and the clarification.

Boomer · 04-02-2005, 01:19 PM

Thanks, everyone, for a nice April Fools Day.

FWIW, the abstract wass utter nonsense

ScottT1980 · 04-02-2005, 01:36 PM

I thought that abstract looked a little fishy. No methods, no real data, all speculation... Nevertheless, you had me...

Good one indeed!!!

04-01-2005, 01:10 AM	#1 (permalink)
Boomer Reef Sanctuary's Mr. Wizard Join Date: Nov 2003 Location: Duluth, Minnesota Posts: 2,211 View Gallery Karma Komment	Toxicity of nitrate isotopes discovered! I just found this article that many reefers may find interesting. Note especially the conclusions at the end of the abstract: Toxicity of 15N and 18O isotopes of nitrate in seawater. Lehnenn, Molz F.; Sidnan, Daniel P.; Barry, Willard T. Department of Marine Chemistry, Florida University, Coral Gables, FL, USA. Marine Chemistry Monthly, April 1, 2005, 1-55. Abstract We report 15N/14N and 18O/16O ratios of nitrate in toxicity tests involving benthic chamber incubations in the continental shelf sediments of the Great Barrier Reef to deconvolve the effects of nitrate isotope toxicity. Previous researchers have reported little toxicity due to nitrate, but our studies show greatly increased toxicity for the 15N/18O isotope of nitrate. Ests. of toxicity from benthic flux stoichiometry are 0.9-2.5 mmol N/m2-day. Between 46 and 100% of the total toxicity can be explained by nitrate istotopes with 15N. In general and independent of the toxicity and the fraction of remineralized N being tested, nitrate 15N/14N and 18O/16O ratios do not change significantly with progressive nitrate depletion in corals. A lack of change in nitrate 15N/14N could be due to either the lack of effective N isotope fractionation assocd. with nitrate toxicity, or the balancing of an 18O isotope effect by the addn. of low-15N/14N nitrate from nitrification. However, the lack of an increase in nitrate 18O/16O indicates that the isotopic fractionation specifically assocd. with toxicity is, in fact, negligible. The coupled N and O isotope measurements also indicate that there is great concern in the gross efflux of 15N-depleted nitrate from nitrification, leading to the conclusion that scientists keeping organisms in closed systems, such as aquaria, are likely slowly killing them with 15N isotopes. __________________ Randy Holmes-Farley Want to talk chemistry? Try the Reef Chemistry Forum at Reef Central __________________ Boomer Want to Talk Chemistry ! The Reef Chemistry Forum Want to See More ! The Coral Realm If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be.

04-01-2005, 02:07 AM	#3 (permalink)
rckmtl Serpent Star Join Date: Mar 2005 Location: Aurora, Illinios Posts: 231 View Gallery Karma Komment	oooh, oooh, let me quess! I'm gonna guess that what it is saying is that, in a closed system there are not the same amounts/ratios of all the different ions that contribute to the denitrification process as there are in a natural enviroment(the ocean). As a result, the'bad' ions aren't really detoxified the way people think they are, but are in fact slowly building up to lethal levels. I'm I right, or am I totally off course?????? either way, I do not agree with their conclusion, becuase the denitrification process in aquaria is only to keep things stabilized in between water changes. Then you do one and out goes a big chunk of all the bad stuff. If the very generalized statment at the end were 100% true then everyones fish would die off after 5 or 10 years, and obviously there are many healthy animals that have been in captivity longer then that. __________________ -Ellen- Where did all the water go...

04-01-2005, 09:10 AM	#5 (permalink)
Woodstock The Wand Geek was here. ;) Join Date: Nov 2003 Location: North Carolina Posts: 23,689 View Gallery Karma Komment Add yours!	My interpretation after only one cup of coffee..... NitrAtes are very harmful to our tank inhabitants and at only 15N/Isotope the corals are slowly dieing 15N/Isotope = _________? (ppm nitrAtes) __________________ ~Doni Marie~ *GOT ICH???* 120 Reef Chronicle ~ *Breeding Picasso Clownfish~* *Massive 300 gal growout~* *My Anemone & Picasso Tank ~* *Picasso & Snowcasso for sale~* "Energy and persistence conquer all things." Benjamin Franklin __________________________________________________ ______________________________________________

04-01-2005, 12:14 PM	#6 (permalink)
Boomer Reef Sanctuary's Mr. Wizard Join Date: Nov 2003 Location: Duluth, Minnesota Posts: 2,211 View Gallery Karma Komment	Ellen That is about it and your option is about the same as mine ions Lets explain that. Nitrate is NO3- an ion, know as a anion as it has a negative charge . It has an overhaul charge of -1. Many atoms, such as N, O, Ca, Mg may loose or gain an electron and become an ion. However, those same ions may have lost or gained a neutron in the nucleus and these are know as isotopes. Oxygen often comes as either isotope 18 or 16. Meaning the oxygen has either 18 or 16 neutrons. Same for the Nitrogen, 14 or 15 neutrons. These extra neutrons just change the weight of the atom. Some isotopes are more common than others and some are more toxic. These researchers are being very specific as to what isotopes make up the nitrate ion. 15 N Nitrate is the highest concentration of the two and it is the 15-Nitrate in their study that is accumulating the most, thus the accumulation of 15-Nitrate may bring about nitrate toxicity in close systems like aquariums. Woody 3 ppm 15N nitrate is the same as 3 ppm 14N Nitrate. Our trest kits don't know the difference between the two. 3 ppm Nitrate will be some of both, 14N or 15N. Isotopes are pretty much a geologic age thing. If you had a tank a million years ago the ratios would be different for the 14 and 15N. It is like the oxygen (O2) you breath, some will 16-O2 and some will be 18-O2 __________________ Boomer Want to Talk Chemistry ! The Reef Chemistry Forum Want to See More ! The Coral Realm If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be.

04-01-2005, 01:10 PM	#7 (permalink)
angnak Torch coral Join Date: Nov 2003 Location: Charlotte, NC Posts: 555 View Gallery Karma Komment	HMMMM.... Yes doctor I concur. Very interesting and I also think we are taking out the bad with water changes. __________________ 210gal AGA SW tank. 3 250w MH 4 160w VHOs, 30 gal refuge, ASM Skimmer, Orange shoulder tang, Black tang, Naso tang, 2 orange percs, 2 black percs, 1 lawnmower blenny, a pair of scooter blennies, 5 cleaner shrimp, 5 peppermint shrimp, zebra crabs, halloween crabs, scarlett crabs, various other crabs and snails, 1 rock anemone, 2 colonies of button polyps, 3 colony of star polyps, 3 BTAs, monti cap, various acros

04-01-2005, 01:35 AM	#2 (permalink)
gussy Torch coral Join Date: Jan 2005 Location: San Francisco Posts: 579 View Gallery Karma Komment	Umm...what does it say?

04-01-2005, 01:30 PM	#8 (permalink)
Travelin Reef Limpet Join Date: Nov 2003 Location: newton, nj Posts: 136 View Gallery Karma Komment	so does all of this still mean we can't put a screen door in a submarine?

04-01-2005, 01:41 PM	#9 (permalink)
Boomer Reef Sanctuary's Mr. Wizard Join Date: Nov 2003 Location: Duluth, Minnesota Posts: 2,211 View Gallery Karma Komment	Yes Trav, that is correct __________________ Boomer Want to Talk Chemistry ! The Reef Chemistry Forum Want to See More ! The Coral Realm If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be.

04-01-2005, 10:19 PM	#11 (permalink)
jhnrb Scopas Tang Join Date: Feb 2005 Location: Eureka, CALIF. Posts: 482 View Gallery Karma Komment	Thanks for the article and the clarification.

04-02-2005, 01:19 PM	#12 (permalink)
Boomer Reef Sanctuary's Mr. Wizard Join Date: Nov 2003 Location: Duluth, Minnesota Posts: 2,211 View Gallery Karma Komment	Thanks, everyone, for a nice April Fools Day. FWIW, the abstract wass utter nonsense __________________ Boomer Want to Talk Chemistry ! The Reef Chemistry Forum Want to See More ! The Coral Realm If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be.

04-02-2005, 01:36 PM	#13 (permalink)
ScottT1980 Reef Lobster Join Date: Nov 2003 Location: Raleigh, NC Posts: 1,484 View Gallery Karma Komment	I thought that abstract looked a little fishy. No methods, no real data, all speculation... Nevertheless, you had me... Good one indeed!!! __________________ My Tank

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