Someone please answer my question

[graveyardworm]

I've asked this question in a couple different theads and so far its been overlooked, or maybe there isnt an answer.

I have a question regarding feeding vs dosing. Do seagrasses take in nutrients better through the roots or the leaves? If they do take in nutrients better through the roots would it be better for the plant if regular food was introduced for bacteria to convert to nitrates? This would serve two purposes I think. 1) It would be a more natural way to dose nitrates and would also involve ammonia and nitrites which I think the plants utilize as well (please correct me if I'm wrong) not to mention PO4, potassium, and CO2 would result. 2) Normal feeding also helps to maintain sand bed infauna which are important to stir the sand bed and bring the nutrients to the roots.

Anyway the method I've chosen for introducing nutrients to the QT that the seagrasses are in is to feed it. The tank is going through a small cycle. I've introduced some of my homegrown grazers to keep the algae down, as well as some other worms and critters from my display, and a piece of LR from my sump. The diatom bloom seems to be subsiding, the grazers did a good job keeping the seagrass clean.

 

[Alentino]

You need to summon the seagrass goddess, Samala

 

[Samala]

You'll have to forgive me David, my memory has really gone sour lately and I didnt make a note to get back to this question of yours. I cant remember which thread its in now either, so I'm glad you made a new one.

I do not know currently if they have a preference between roots and leaves for accessing nutrients. Yet another burning question I'm sure we'd all love to have answered. Its safe to say they do use both zones. If you want to provide a super nutritious substrate and continually feed it so that it has only a slim chance of becoming exhausted in the future then go for it.

I have been hoping that detritus that is continually incorporated into my sandbeds would be enough along with my dosing regimes.

How are you thinking of feeding the substrate? Injecting food into the sand so that the inverts can feed on it? Or feeding the rest of the tank and using the detritus to feed it? Or.. when you say feed the bacteria.. are you thinking of vodka dosing or something else? If you can expand your ideas it would help us all get a sense of what you want to attempt, and how it might be best to try it.

Yes, plants will use ammonia and nitrites. There is some debate that they actually prefer to use ammonia as it is already reduced and easier to metabolize. However, all those little annoying algaes like cyano will love ammonia/nitrite in your tank and respond to it more quickly than the seagrasses can be expected too. If you have plenty of biological filtration and the bacteria can quickly process the ammo/trites to trates than there is little worry for cyano or other nuisances to bloom (diatoms might play into that too). I notice when I make large increases in the bioload that I get cyano blooms as the bacteria slowly respond to the higher N (and other nutrient) loads.

As always, I encourage experimentation. If I can help I'd love too. I'm grateful that you're interested in this as not everyone wants to go about adding KNO3, FeEDTA and other miscellaneous (but beneficial) fertilizers to their tanks. Telling them to up the feeding, and to have a method worked out, is going to be much more palatable. Piercho probably would have great input on this.. Bill too if he sees the thread.

>Sarah

 

[graveyardworm]

My idea and method was simple. I think that people tend to overlook all the different pods, worms, and other little things in their tanks. In the abscence of fish they discontinue feeding the tank because the most obvious reason to feed is non existant.

Currently in my lagoon tank I'm dropping in alot of food, for a long time it was just a clown goby, and my suncoral. The populations of mysis, various pods and worms have exploded, and I'm having trouble maintaining enough algae for my snails and conch. So I thought the same thing could be done in a seagrass only tank. This way nutrients could be mintained by normal feeding rather than dosing, and I thought this could be more beneficial to the seagrass especially if nutrient uptake through the roots is high.

So for the seagrass currently in my QT I was going to try something. In the evening when I feed my suncoral I'm going to add some food the seagrass tank and monitor nitrates to see what happens. So far its going as expected The algae is beginning subside and the copepod population is growing. I've also added some hair worms collected from another tank, and some little feather dusters. Next I'm going to add some bristleworms and maybe a couple nassarius snails. As I increase the food added I will need more things to help process it. Also my nassarius are constantly laying eggs. Maybe in a tank which contains no filtration the larvae will have a chance.

 

[mesocosm]

Here's a reference you may wish to check out ... it's a collection of several different articles:


Initial estimates of the export of leaf litter from a seagrass bed in the Spermonde Archipeligo, South Sulawesi, Indonesia (1996).

Biomass loss and nutrient redistribution in an Indonesia Thalassia hemprichii seagrass bed following seasonal low tide exposure during daylight (1997).

Leaf harvesting and sediment reworking by burrowing alpheid shrimps in a Thalassia hemprichii meadow in South Sulawesi, Indonesia (?).

Nutrient resorption from seagrass leaves (1997).

Nutrient uptake by the leaves and roots of of the seagrass Thalassia hemprichii in Spermonde Archipeligo (1996).

Nutrient cycling in a Thalassia hemprichii seagrass bed in South Sulawesi, Indonesia (?).



Don't be disturbed by the German language intro page ... it turns into English on the next page. Also, be prepared to wait a few moments while it loads ... it's 109 pages.

Full Collection (pdf)
http://webdoc.ubn.kun.nl/mono/s/stapel_j/nutrdyini.pdf


HTH

 

[graveyardworm]

Great article, thanks. Havent had time to read it all yet.

 

[piercho]

There is a dynamic here with bacteria competing with plants for ammonia-nitrite-nitrate that must be considered. Given adequate sources of organic C, bacteria will "completely" consume or convert introduced nitrogen and it will not become available to the plants. Water column nitrite-nitrate levels tend to be low in tanks older than 3 months with DSB due to bacterial consumption of N, this is a main reason many switched to DSB from BB for stony coral tanks earlier this decade. So, while we feed our tanks protein-rich (high N) foods, and a fair percentage of this food winds up composting in the bed, it does not necessarily mean that the nitrogen from the food becomes available to the grass. My grass growth is mostly limited by the availability of usable N, IMO.

I think I have a higher bio-load than Sarah, feed heavier, have higher light levels, and my bed is older and filthier. My shoal grass blade production is sparse and slow, hers is dense and prolific. She gets better blade production solely as a result of her dosing water column nutrients, I’m pretty sure.

Neither of us gets the kind of grass production that I see on the eel grass flats here in Puget Sound. In that case, I think that the grass is mostly acquiring the nutrients from its roots. These grass flats are incredibly fertile â€"œ and anoxic â€"œ sediments. I don’t know how this compares to Caribbean grass beds, and I don’t know how to duplicate these conditions in a closed system.

One thing I am considering for Tank2 is injecting nutrients directly into the bottom of the substrate using a peristaltic pump. I got that idea from a post on a fresh water plant website Sarah has linked previously. If you want to feed the grass nutrients through their roots without increasing water column nutrient levels, this might be a method to consider.

 

[noschmo]

If you change your screen name, you are likely to get more responses! Its a little on the sick side, don't you think or don't you?

 

[graveyardworm]

HUH?? You just earned a trip to the ignore list, until you can add something worth listening to.

 

[stevemc]

Try dosing with iron and manganese, to the sand bed. The ammonia or nitrite and nitrates are in the water, and will feed them anyway. You can go to your nearby nursery and find small amounts of each. Or you may have to buy large bags and divide it up at your meetings. Just start off with a very tiny amount of each and see how it works. That works though. Steve.