KEPENTINGAN/PERANAN CAHAYA : Mempertahankan suhu
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KEPENTINGAN/PERANAN CAHAYA :
Mempertahankan suhu Proses fotosintesis Siklus hidrologi
SATUAN CAHAYA : Watt, Joule, Lux, Langley, Kalori Foot candle,
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Siklus hidrologi
Sumber: Max Planck Institut For Meteorology (1999)
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PANJANG GELOMBANG ( λ ) : 100 – 3.000 nm (10-9m)
< 300 nm : Ultra Violet
300 – 700 nm : PAR – Photosynthetic Active Radiation Visible Light
300 – 490 nm Biru 490 – 585 nm Hijau 585 – 700 nm Merah
555 nm Kuning Hijau, Pusat Cahaya
> 700 nm : Infra Red
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The electromagnetic spectrum. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com).
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html
The electromagnetic spectrum:
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ALAT PENGUKUR CAHAYA :
LUX METER, PYRHELIOMETER
ALBEDOMETER
PHOTOCELL IMMERGEABLE
SECCHI DISK/DISC
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Penurunan cahaya karena :
1. Refleksi – dipantulkan
2. Absorpsi – diserap Refleksi + Absorpsi + Transmisi = 1
3. Transmisi – Dibiaskan
datang pantul
bias
α1 α2
α3
α1 = α2
α1 > α3
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CAHAYA DARI MATAHARI (%) YANG SAMPAI KE BUMI
Total ; Asal Hilang ; Asal Sisa ; Asal
Luar Atmosfir 100 ; 100 48 ; 48 52 ; 52
Atmosfir 100 ; 52 60 ; 31 40 ; 21
Permukaan air 100 ; 21 50 ; 10,5 50 ; 10,5
Dari matahari : 1,92 gcal/cm2/menit
Daerah ekuator : 800-900 gcal/cm2/hari
Kutub pada musim panas : 1.100 gcal/cm2/hari
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Rumus LAMBERT-BEER
Iz = Io. e-kz
z = Kedalaman Iz = Intensitas cahaya pada kedalaman z Io = Intensitas cahaya pada kedalaman 0 (permukaan) e = Bilangan eksponensial k = Coeficient of Extinction, ( Koefisien Peredaman, Pemadaman, Peredupan)
Kz = K air + K Partikel Tersuspensi + K Diss.coll.compound
Nilai K berbeda : Setiap Perairan Setiap Waktu Setiap Panjang Gelombang Setiap Kedalaman
RUMUS LAMBERT-BEER
Iz = Io e-kz
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Iz = I0.e-kz dikalikan Ln
Ln Iz = Ln Io.e-kz
= Ln Io + Ln e-kz
= Ln Io – kz Ln e (Ln e = 1)
= Ln Io – kz
Ln Iz + kz = Ln Io
Kz = Ln Io – Ln Iz
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Kz = Ln Io – Ln Iz
Depth (m) Nilai Cahaya (%)
Ln K
0 100 4,61
0,16
2 86 4,45
0,15
4 74 4,30
0,52
6 44 3,78
0,15
8 38 3,63
0,14
10 33 3,49
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ZONASI VERTIKAL CAHAYA DI DALAM AIR
0 1 50 100Incident Light (%)
Depth Fotosintesis > Respirasi
Fotosintesis = Respirasi
Fotosintesis < Respirasi
Compensation Depth
ZONE PHOTIC
ZONE APHOTIC
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Pukul Cahaya di permukaan
Cahaya di kedalaman 5 m
% Lux % Lux08 100 100 1 110 100 500 1 512 100 1.000 1 1014 100 900 1 9
Misalnya agar fotosintesis = respirasi diperlukan cahaya 5 lux
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KESUBURAN PERAIRAN DILIHAT DARI CAHAYA
1. Subur (Eutrophe) 0 – 3 m2. Moderat/Sedang (Mesotrphe) 3 – 6 m3. Miskin/tidak subur (Oligotrophe) >6 m
Catatan : - Perairan Tawar - Kedalaman perairan > 6 m
RATA-RATA NILAI PRODUKSI PRIMER BERSIH BERBAGAI LINGKUNGAN (Valiela, 1984)
Lingkungan g/m2 /Tahun
Laut Terbuka 125
Upwelling 500
Continental shelf 300
Hamparan alga dan terumbu 2.500
Estuari tanpa rawa (marsh) 1.500
Total Laut (marine) 4.925
Terrestrial (daratan) 737
Rawa (swamp and marsh) 3.000
Danau dan sungai 400
Total kontinental 4.137
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Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html S2 Produktivitas Perairan
ChlorophyllsTwo types of chlorophyll are found in plants and the green algae. · chlorophyll a, & · chlorophyll bThe difference in their structures is shown in the figure (red disks).
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chlorophyll.html
http://www.chemsoc.org/networks/learnnet/cfb/Photosynthesis.htm
Chlorophyll
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the structure of beta-carotene, one of the most abundant carotenoids. Note: the system of alternating single and double bonds that in this molecule runs along the hydrocarbon chain that connects the two benzene rings.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chlorophyll.html
http://www2.mcdaniel.edu/Biology/botf99/photo/p3igments.htm
Xanthophylls are essentially oxidized Carotenoids and contain oxygen. They are usually red and yellow and do not absorb energy as well as cartenoids. They are also fat soluble.
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http://www2.mcdaniel.edu/Biology/botf99/photo/p3igments.htm
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http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html S2 Produktivitas Perairan
THE LIGHT REACTIONS OF PHOTOSYNTHESIS
http://employees.csbsju.edu/hjakubowski/classes/ch331/oxphos/olphotsynthesis.html S2 Produktivitas Perairan
Figure 2. Absorption spectrum of isolated chlorophyll and carotenoid species. The color associated with the various wavelengths is indicated above the graph.
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ENAN M ADIWILAGA
Lantai 2 Wing 14 (N) Nomor 2 – Menghadap ke danau
Telp. Facs 8421731
Rumah : Jl Soka No 18 Kampus IPB Darmaga (Perumdos) Bogor 16680
Telp.Facs. 8621325
HP 0811118108
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