H^i thao khoa hpc - Hpp tac Qu6c tg trong digu tra, nghign cuu tai nguygn vA m6i truimg bign
M O HiNH HOA PHAN BO CHLOROPHYLL-A 6 VUNG BIEN NAM TRUNG BO TRONG KHUON KHO DU AN HQP TAG VIET - D C C
Phan Minh Thu. Nguyen TSc An Vien Hdi Dircmg Hoc, 01 Cdu Dd, Nha Trang
Email: [email protected] Tom tat:
Dua vdo ket qud dieu tra cua cdc chuyen khdo sdt trong chucmg trinh hgp tdc Viet - Dire "Nghien cmi hien lugng nirdc trSi vd dieu kien sinh thdi lien quan a them luc dia Nam Vi^t Nam ", bdo cdo tgp trung nghien cuu cdc dgng phdn bd ciia chlorophyll-a (Chl-a) .& viing bien Nam Trung bo:
(1) Hdm lugng Chl-a bien dpn^ mgnh. Tdng Chl-a cue dgi khong phdi ndm a tdng mat md dugc phdn bo a tdng 20-80m, thgm chi Id tdng 100m.
Mot so tram xuat hien 2 dinh chl-a phdn bo a viing khai, trong khi do, Igi cdc tram gdn ba co hien lugng nude Iroi, dinh chl-a di chuyen len tdng mat.
(2) Xdy dimg hdm phdn bo Chl-a theo do sdu. Hdm lugng chl-a phdn bo a dgng phdn bo chuan gaussian dugc ndng len mgt gid trf nen ndo do (dgng thudng gap), hogc dgng phdn bo chudn md rgng vdi 2 dinh chl-a (a cdc tram ngodi khai vd co xuat hien hien lugng nude Iroi), hoac dgng bdn phdn bo-chudn (dcdc trgm ven bdvdcdxudi hien hien lugngnudc Iroi).
(3) Ngodi ra, qua nghien ciru phdn bo Chl-a theo do sdu con cho phep xdc dinh tdng nuac xdo trgn cho viing nude.
Kit qud xdc dinh nhung ddc trung phdn bo Chl-a gop phdn quan trgng trong nghien ciru ddnh gid ndng sudt sinh hgc so cdp lich phdn, dgc diem chu trinh sinh dia hoa, ddnh gid ca sa thirc dn ciia vuc nude vd cdc vdn de sinh thai kinh te viing hien nhiet ddi.
MODELING OF CHLOROPHYLL-A DISTRIBUTION IN THE SOUTHERN CENTRE MARINE OF VIETNAM UNDER THE VIETNAM •
GERMANY COOPERATION PROGRAM Abstract: . ,-^
Based on investigated results of cruises of the Vietnam Germany cooperation program "Study on upwelling phenomenon and some relative ecological conditions of the continental shelf waters in the South of Vietnam ", the paper aims to identify the shape of chlorophyll-a (Chl-a) distribution in marine region of the southern centre in Vietnam.
(1) Chl-a concentration varied significantly. The maximum Chl-a concentration was not found in the surface layer al almost study station. It could be located in the water layer at from 20 lo 80m, sometimes lo 100m.
Workshop: "International Cooperation on Investigation and Research of Marine Natutal Resoaroe and Environment"
Some stations located in off-shore waters had two peaks of Chl-a concentration, whereas at some stations located in coastal waters with upwelling, the peak of chl-a moved lo surface layer.
(2) Chl-a concentration was a function of depth. The shapes of Chl-a concentration were shift Gaussian curves (normal shapes), whereas when upwelling exited in marine waters, the shapes were extensional Gaussian curves with two Chl-a peaks (in off-shore regions) or half of shift Gaussian curves (in coastal waters).
(3) In addition, the results also identified the mixed depth layers based on distribution of Chl-a concentration in water bodies.
Finally, understanding characteristics of Chl-a distribution in water bodies takes an important role of assessment of integrated primary production, biogeochemical cycles, food web/food chains arid other ecological economic fields in tropical marine regions.
M d D A U
Ham lupng Chl-a ti-ong nuoc khong chi duoc sil dung nhu la mpt chi tieu dl danh gia chat luong moi traong (Antoine et al., 1996) ma con la chi tieu d6 xac djnh CO so nang lupng cho tiiuy vyc (Nguygn Tac An, 1985). Do do, viec xac dinh chinh xac ham lupng Chl-a trong cpt nuoc gop phin quan frpng trong viec xSy dimg jphuong an quan ly, khai tiiac va bao ve tai nguyen va moi frucmg biSn.' Danh gii, xac djnh him lupng Chl-a ti-ong vung nuac 6- dai ducmg co th4 duoc xac djnh bang phuang phap giai doan anh viin fliam nhu giai doan hi anh mdu dai duong SeaWiFS (Hyde et al., 2007), MODIS (Nguyen Tac An et al., 2003), hoac bing phuang phap xac dinh tiirc tiep tai hien ti-uong. H?n chS cua cac phuang phap n4y la chi xac dinh dupe ham lupng tai mpt tang nuac ma khdng xac djnh dupe tSng lupng chl-a trong toitn cot nuac hojc ting quang hpp. Theo Piatt and Sathyendranadi (2000), han ch6 nay co thi khic phuc bing phuang phap mo hmh hoa.
Nghien ciiu vimg nude tr6i Nam Tmng Bp dupe tiln hanh tir nhimg nam 1990 (Vo Van Lanh, 1997) nhung chua giai quyet dupe vin dl xac dinh co so nang lupng ciing nhu phan bo sinh luong tiiirc vat, nang suat sinh hpc trong toan cot nuac vin chua dupe xac djnh.
Hon niia, hau nhu cho den hifn low
V .-'.,.' ' A '
- -^KX ' S ' '
/
• ^ ^ /
,
w '' -.fc
imr
«i ' , y
--
V - -
.X
l i t r
. i^!''.'
% '. ' •
•'••-- % \t
"' ^ ll 2>M
;»'' " ' . ' i ^ M
; > i ^ : -J/^/l / " «=
• T / -:» •,'
I ? '' "> M.
d: -i'
•• , ; <Hinh 1: Tram vi thu mlu trong chuygn khao sat VG7 (hcTD tac aiira Viet Nam - Diic)
Phan Minh Thu
H&i thao khoa hpc - Hpp tac Qu6c tg trong digu tra. nghien c-.'-; tAi nguygn va mfli truimg bign
nay rit thilu nhiing chuyin khao sit a viing biln nude s&u. Hiu hit, nhttng nghien ciJru tren biln dupe thyc hign bai c4c chuong trinh hpp tic qu6c tl, dSc biet trong thdi gian gin diy, nhttng chuyin khao sit o Bien Dong dupe thuc hien bai chuong trinh hop tic vdi My, Lien bang Nga, EU, Sure, Philippine,...
Trong nghign ciiru nay, dua vio kit qui hpp tic gitta Vi^t Nam v i Dilc trong chuygn khao sit VG7, bai bao tap trung phan tich phin b6 ham lupng Chl-a a viing nuoc troi Nam Trung Bo.
PHUONG PHAP NGHIEN CUU
Chuyin khao sit hpp tic Viet - Dire (VG7) dupe tiln hanh t t t n g i y 8/7- 28/7/2004 trgn viing bign Nam Trang Bp. Day la viing thucmg xuygn xuit hi?n hien tupng nude troi (Va Van Linh, 1997) thay ddi khi hiu._ Trong chuygn khio sit na^, miu nudrc d l xic djnh Chl-a duoc thu tai 41 tram vdi tinges! miu l i 263 miu. Mau dupe thu tai cic ting 5, 10, 20, 40, 60, 80, 1(30, 150 vi tang Chl-a circ dai. Trong dpt khao sit niy, ngoai hien tupng giao miia, viing nghien ciiu cdn xuit hign hien tupng bimg no phit trien tio lam.
Sau khi thu, miu nude dupe Ipc ngay bang mang Ipc GF/F vdi thg tich Ipc ttt 2- 5L tiiy thuSc vao ham luong Chl-a (mau trgn man loc). Sau do, miu dupe chilt suit bang Acetol 90% trong 24 gid. Sau dd, dung dich chilt dupe do bang miy quang pho vdi cuvet 5cm tai cac budc sdng 630, 647, 664 v i 750 nm. Ham lupng Chl-a dirpc tinh toin theo Jeffrey and Humphrey (1975).
B(.) = H„+-|=.xJ-(^-^'»a
B{z]
z B,
"iN^
—li^.
2ff2 H--
Hinh 2: Dang him phan b8 Shifted Gaussian ciia Chl-a trong c6t nut5rc (Piatt and Sathyenranath, 2000)
a\2n
Bo: ham luong Chl-a nen
h: Ting him lupng Chl-a d vung dinh H: Do cao cua dinh Chl-a c\rc d?i trong c6t nirdc
o: Do md cOa dinh Chl-a z,^: Do sau cita tdng Chl-a c\rc d£ti B(Zn,) = Bo + H : Him luong Chl-a c\rc dai
Ham phan b6 Chl-a trong cot nude cd dang Shifted Gaussian (Piatt and Sathyenranath, 2000; Piatt et al., 1991) va d vung Biln Dong c 0 i ^ 6 ' d ? n g tuong ty (Phan Minh Thy va Nguygn Tic An, 2005). Him Shifted Gaussian dupe ti-inh bay a hinh 2. Cic gii trj trong him Shifted Gaussian dac trung cho timg viing biln cu the.
Phan Minh Thu 415
Workshop: "Intemational Cooperation on Investigation and Research of Marine Natutal Resource and Environment"
KET QUA NGHIEN CUtJ
Bac trimg phan bd Chl-a trong vilng nu&c trbi Nam Trung Bp
Kgt qua khao sit VG7 cho thiy ham lupng Chl-a biln dpng manh theo phuang ngang (bang 1 va hinh 3) va phuang thing dilng (hinh 4), dao ddng trong khoing:
0,026 - 7,168 mg/m', tiung binh: 0,647 ± 0,919 mg/m'. Tai hiu hit cic h^m, him lupng Chl-a thudng thip han 0,5 mg/m', chi cd khu vyc gan ciia song Ddng Nai va phia Nam Bmh Thuin thi Chl-a rit cao, cd thg do xuit hi$n hign tupng nude troi (Giai doan nay cd gid Idn) (hinh 3).
Them vao dd, hmh 4 cho thay ham lupng Chl-a cue dai tiong toan cOt nude, thudng khong nam d ting mat (tang hap thy nhigu anh sang nhat va la ting xio dpng manh) ma nam d tang dn djnh - ting Chl-a eye dai. Diiu n^v rv-nq rilin Jjonj vdi cac nghign cu:u trudc day d vung Bign Ddng va khs ^ , - ^.:
Sathyendranath, 2000; Phan Minh Thy, Nguyin Tic An, i>,„.,, ..t,-^;.- .— . ^ and Phan Minh Thu, 2007). Chl-a chi xuat hien 6 ting mat khi cd hi|n tupng nude troi hay khu vyc nude ndng (dp sau nhd hon 30m) va Chl-a eye dai thudng tjp tmng d cac ting nude tu: 0 -15 m. d cac tram cd dp sau nhd (<50m), Chl-a eye dai thudng bat gap frong cac ting nude tii 10 - 30m. Tai cic ttam cd dO sau Idn, chl-a eye dji thudng tap trung frong cic ting nude cd dO sau frong khoang 40 - 60m, co khi dgn 80m. Tuy nhign, theo phan bd binh thudng, tii cic dp sau Idn hon 80m, Chl-a giim din. Tai tram 54 xuit hien dinh cao Chl-a thli 2 d dp siu 100 m nhung dinh cao nay nhd hon dinh cao thur nhit. Diiu niy cd lien quan din 2 ylu td co bin li ngudn dinh duong va inh sing.
Bing 1: Ham lugmg Chl-a (mg/m')vimg biln Nam Trung B6 - Viet Nam Thong so
Ctrc ti6u C\rc dai Trung binh Sdmau
Tang mat
0,100 6,470 0,706 ± 1,259 41
Ting cvrcdai
0,392 7,168 1,490 ± 1,397 41
Toan cpt nuac 0,026 7,168 0.648 ± 0,919 263 Nguln: Nguyin HOu Huan va Phan
Minh Thu (2007)
Hinh 3: Chl-a (mg/m') ting 5m
Phan Minh Thu
Hpi thao khoa hpc - Hgp tac QuQc tg trpng digu tia, nghign cuu tai nguygn va mpi tniong bien
MJt cit 6 sau khi co gio Idn Mat cat 7 Hinh 4: Phan bl ham luang Chlorophyll-a qua cac mat cit (chuyin VG7)
Phan Minh Thy 417
Workshop: "intemational Cooperation on Investigation and Research of Marine Natural Resource and Environment"
Md hinh phan bd Chl-a trong todn Cft nirdc
Dya vao sd lieu thyc do va bing phuong phip md hinh (hinh 2), nhttng dac trung phan bo Chl-a frong toan cot nude thg hien d bang 2. Ting Chl-a cue dai dupe xic djnh bing md hinh dao ddng tii 5,00 - 70,09 m, tiling binh la 40,14m vdi him lupng Chl-a cue dai cd thi dat dupe la 7,32 mg/m'.
Bang 2: Cac thong s6 mo hinh phin b6 Chl-a frong cot nude
Thdng so Thap nhat Cao nhat Trung binh Dp l^ch
Sigma (m)
2,50 26,09 11,83 6,20
B„
(mg/m) 0,037 2,580 0,434 0,604
Zm(m) 5,00 70,09 40,14 18,93
H (mg/m')
0,200 5,320 1,082 1.108
Chl-a c^rc dai (mg/m')
0,381 7,320 1,517 1,433
Dp day tSng xao trpn (m) 3.31 57,75 15,13 11,53 Dya vao kit qua tinh toin va phan tich (hinh 5 va bang 2), phan bd Chl-a cd thi chia ra lim 3 dang co bin sau: (1) dang phan bd chuan (hinh 5, ttam 55): phuang phip mo hinh cho phep xac djnh dupe tang xio frpn mjnh mOt cich chinh xic; (2) dang phan bd 2 dinh (hinh 5, ttam 54), vdi cic gii frj tinh toin cua dinh phia fren cho phep xic djnh duac dp day cua ting xio frpn manh; (3) dang bin phan bl (hinh 5, ttam 51) thudng tdn tai d viing nude ndng vimg ven bd, nlu cd gii fri cita dinh nam d tang siu ciing cho phdp xac djnh dupe ting xio trpn manh nhung nlu xiy ra hifn tupng nude frdi hoac dinh Chl-a eye dai di chuyin len ting mit sS khdng xic djnh dupe ting xio frpn. Khi dd, d l xic djnh dupe ting xao frpn, cin thilt phii dua vao cic phuang phip tinh toin khic nhu md hinh T-S (Nhiet dp - dp man) hoac phan bd nhiet dp nude biln.
ttinikJ?i«tiil4|niE/ii)>] ttim b/^tMs |nlg/nf] Hsmlfpiijflilalmj/nfl
. . . ^
Tram 51
Dang d^ng phan bl Tram 55
Dang phan bl chuin Tram 54 Dang phan bl 2 dinh Hinh 5: Cac dang phin bl Chl-a d vilng biln Nam Tmng Bo
Cic dang phan bd ciia Chl-a trong nghien cuu cung duac Nguyen Tac An and Vo Duy Son (2010) de cap khi nghien Cliu vl nang suit sinh hpc d Biln Ddng.
418 Phan Minh Thu
Hpi thap khoa hpc - Hgp tac Qudc tg trpng dieu tra. nghien ciru tai nguyen va moi truimg bien
KET LUAN
Vdi sy hpp tic nghign ciru khoa hpc gitta Viet Nam va Cdng hda Lign bang Dire trong ITnh vuc Hii Duong, nghien cim vl phan bd Chl-a trong cdt nude da dupe tiln hanh v i dat dupe nhilu kit qui ding ke. Bgn cjnh kit qua nghien ciiru hi?n trang va die dilm phan bd ciia Chl-a, kit qui xu ly va phin tich cho phdp xic djnh dupe nhttng gii trj die trung ciia phan bd Chl-a nhu him lupng Chl-a ting eye dai v i dp sau ting eye dai, gii trj Chl-a ting xio trpn manh v i dp siu ting xio tron manh. Nhung gii trj nay cd y nghTa khoa hpc vd cung quan trpng trong viec tinh toin ning suit tich phin trong toan cdt nude (Nguyen Tac An and Vo Duy Son, 2010) cung nhu sir dung trong qui trinh img dung phin tich inh viin thim phuc vu nghign ciru hii duong hpc (Nguygn Tic An et al.,-2003).
LOI CAM ON
Chiing tdi chan thinh giii Idi cim on din TS. Biii Hdng Long (Vign trudng Vijn Hii Duong Hpc, Dieu phdi vign dy an hop tie phia Viet Nam) cho phep chiing tdi sir dung sd lieu trong bao cio nay. Chung tdi cung xin cam on Hdi thio da tao diiu kien cho phep trinh biy, trao ddi kit qui nghien ciiu vdi cic ddng nghigp trong va ngoii nude.
T A I L I E U THAM KHAO
1. Antoine D., I. M. Andre and A. Morel, 1996. Oceanic primary production 2: Estimation at global scale from satellite (Coastal Zone Color Scanner) chlorophyll. Global Biochemical Cycles, 10: 57-69.
2. Hyde, K.J.W., J.E. O'Reilly, and CA. Oviatt, 2007. Validation of SeaWiFS chlorophyll a in Massachusetts Bay. Continental Shelf Research, 27, 1677-1691.
3. Jeffrey S.W. and G. F.Humphrey, 1975. New spectrophotometric equations for determining chlorophylls a, b, cl and c2 in higher plants, algae and natural phytoplankton. Biochim. Physiol. PHanzen, 167: 191-194.
4. Nguyen Tac An, 1985. Nang suit sinh hpc cic vyc nude ven bd Viet Nam. Bio cio ting kit dl tai 48.06.13. Vien Hai Duong Hoc, Nha Trang. 131 tr.
5. Nguyin Tic An, Tdng Phudc Hoing Son, Phan Minh Thu, 2003. tTng dung cong nghe vien thim trong nghien ctiu phin bl chlorophyll d Bi6n Dong, Vigt Nam. Hpi nghj
"NhOng vin dl nghien ciu ca bin trong Khoa hoc Su sing 2003", Hul, 25-26/7/2003.
548-551.
6. Nguyen Tac An, Phan Minh Thu, 2007. Biogeochemical Variability of Vietnam Coastal Waters Influenced by Natural and Anthropogenic Processes. Asian Journal of Water, Environment and Pollution, 4: 37-46.
7. Nguyen Tac An and Vo Duy Son, 2010. Primary production models and the problem of estimation of their parameters in various conditions of the water column. Russian.
Journal of Marine Biology, 36, 139-146.
8. Plan, T. and S. Sathyendranath, 2000. Modelling Primary Production. Training material of NP-POGO 2004, Kochi, India.
9. Phan Minh Thu, Nguyin Tac An, 2005. Mo hinh hoa phin bo him lupng Chlorophyll-a cita thuc vat nli trong Biln Dong. Hoi nghi "NhOng vin dl nghiSn cOu ca bin trong Khoa hoc Sy song 2005", Hi Noi, ngay 3/11/2005. I078-I080.
10. Piatt, T., D.F. Bird, and S. Sathyendranath, 1991. Critical Depth and Marine Primary Production. Proceedings of the Royal Society B: Biological Sciences 246, 205-217.
11. Vo Van Lanh (chu bien), 1997. Cac cong trinh nghien ciu vCing nude troi manh Nam Trung Bo. Vien Hai duang hpc, NXB Khoa hpc vi Ky thuat.
Phan Minh Thu 419