NUTRIEN:NITROGE
NSIGID HARIYADI
Dep. Manajemen Sumberdaya PerairanFakultas Perikanan dan Ilmu Kelautan - IPB
ESSENTIAL NUTRIENT
Tucker, MR. 1999. Essential Plant Nutrients: their presence in North Carolina soils and role in plant nutrition
C
biomass-limiting nutrients: membatasi produksi biomass rate-limiting nutrients: membatasi laju produktivitas primer
diffusive boundary layer
urea
• bakteri tertentu• blue-green algae
N2
NO3
NH4+
Siklus Nitrogen di perairan
nitrogen also plays important roles in other water quality processes and may constitute a problem:
1. The oxidation of NH4 to NO3 during the nitrification process consumes oxygen and may contribute significantly to the oxygen depletion of a waterbody.
2. High concentrations of un-ionized NH3 can be toxic to aquatic life.
3. The common form of nitrogen in water is NO3, which itself is not toxic. However, bacteria in the intestinal tract of infants can convert nitrates to highly reactive NO2, which may cause the so-called “ blue baby ” syndrome and death from suffocation. There are strict regulations governing the amount of nitrate that can be present in drinking water.
nitrogen is not as often limiting to plant growth as phosphorus in many natural waters, especially in freshwaters. Thus, most of the eutrophica-tion management efforts are focused on phosphorus control.
Nitrogen di perairan terdapat dalam berbagai bentuk seperti:
Reaksi kesetimbangan amonia dan amonium:
1) NO3- (Nitrat)
2) NO2- (Nitrit)
3) gas N2 terlarut4) NH3 (Ammonia) – gas terlarut5) NH4
+ (ion Ammonium), dan 6) N organik kompleks – dlm jumlah besar
(org N)1. N2 (g) + O2 (g) 2 NO (g)
2. 2 NO (g) + O2 (g) ----> 2 NO2 (g)
3. 3 NO2 + H2O ----> 2 H+ + 2 NO3- + NO
4. NH3 + H2O NH4OH NH4+ + OH-
NITROGEN (N)
Bentuk-bentuk N di alam:
Respirasi Nitrat (denitrifikasi):
5. 2NH4+ + 3O2 2NO2
- + 4H+ + 2H2O
6. 2 NO2- + O2 2 NO3
-
Nitrifikasi: melibatkan bakteri nitrifikasi• Nitrosomonas• Nitrobacter
Total Nitrogen (TN):
Total Kjeldhal Nitrogen (TKN):
Total Amonia Nitrogen (TAN) atau TA:
[ ] = konsentrasi (mol/L atau mg/L)
N-organik
total amonia
Ammonia
Phenol dan hypochlorite (chlorox) bereaksi dalam kondisi larutan basa membentuk phenylquinone-monoimine yang selanjutnya akan bereaksi dengan ammonia membentuk indophenol yang berwarna biru. Kepekatan warna biru sebanding dengan kadar ammonia yang ada.
Phenol + NH3 + 3ClO- ‑‑‑‑> Indophenol + 2H2O + OH- + 3Cl- (Hypochlorite) (biru)
kondisi alkalin/basaSemua amonia(NH3 & NH4
+)NH3
Ammonia - N
Sigid Hariyadi
Phenol + Hypochlorite ⇨ phenylquinone-monoimine + NH3 ⇨Indophenol (biru)
metoda Indophenol (=metoda phenate) ( Utk sampel air dgn kesadahan < 400 mg/L dan berkadar NO2-N < 5 mg/L)
setiap set penentuan ammonia, harus selalu disertai dengan penentuan standar ammonia dan blanko Kadar ammonia yang terukur pada metoda ini adalah ammonia total yaitu terdiri dari NH3 dan NH4
-, karena pada larutan bersuasana basa kuat semua ammonia berada dlm bentuk NH3 TAN
Prosentase NH3 thd ammonia total (TAN) sangat dipengaruhi oleh:• pH
• temperatur • salinitas air payau & air laut
Sumber: Trussel (1972) in Boyd (1979)
Sigi
dHar
iyad
i
Total Ammonia Nitrogen
% NH3 = 100 1 + antilog (pKa – pH)
% un-ionized ammonia:
15 20 22 24 25 26 27 28 29 30
9,56 9,40 9,33 9,27 9,24 9,21 9,18 9,15 9,12 9,09
31 329,06 9,03
Temp (oC)pKa
pKa = -log (Ka)Ka : konstanta ionisasi
Amonia dan Amonium:
[ ] = konsentrasi (mol/L)
Konstanta kesetimbangan amonia Ke dipengaruhi oleh temperatur (T):
T dalam C pada 25 C
Proporsi amonium thd total amonia (TA):
Proporsi amonia thd total amonia (TA):
total amonia
Siklus Nitrogen
Sigi
dHar
iyad
i –
2011
Siklus Nitrogen
Siklus N antara fitoplankton-bakteri-zooplankton
Siklus N
Sigi
dHar
iyad
i –
2011
Siklus N
Distribusi vertikal amonia dan nitratdi danau ter-stratifikasi
KLASIFIKASI STATUS TROPHIC PERAIRAN (OECD, 1982)
Oligotroph Mesotroph Eutroph Hipertrophi
Total P (μg/l) 3.00 -17.7 (8.00)
11.0-95.6 (26.7)
16.2-386 (84.4)
750-1200
Total N (μg/l) 307-1630 (661)
361-1387 (753)
393-6100 (1875) -
chl-a (μg/l) 0.30-4.50 (1.70)
3.0-11.0 (4.70)
2.70-78.0 (14.3) 100-150
Max chl-a (μg/l)
1.30-10.6 (4.20)
4.90-49.5 (16.1)
9.50-275 (42.6) -
Secchi disk (m)
5.40-28.3 (9,90)
1.50-8.10 (4.20)
0.80-7.00 (2.45) 0.4-0.5
Di dalam sampel plankton, rasio atom = 106 C : 16 N : 1 P
N-P ratio sediaan nutrien bagi perkembangan algae
Normalnya ⇨16 atom N : 1 atom P7.2 mg/L N : 1 mg/L P
“Biologically available” N = nitrat + nitrit + ammonia“Bio-available” P = orthophosphate
konsentrasi dari masing-masing N dan P tetap perlu diketahui
Bila N-P ratio < 7 ⇨N potensial sbg faktor pembatas
Bila N-P ratio > 8 ⇨P potensial sbg faktor pembatas
Konsep N-P ratio:Redfield ratio (1963)
Referensi:①
②
③
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