^ uni NGHI KHOA HOC T O A N Q U O C Vg SINH T H A I V A T A I N G U Y £ N SINH VAT UKN THU' 5
" DANH GIA KHU HE THlTC VAT NOI
THUOC HE THONG THUY L<jl HO DAU TIENG NAM 2012
HUYNH VU NGQC QUY, DO THI BICH LQC Viin Ky thual Biin Trong nhii'ng nam ciia the ki XX, cac nha sinh hgc da cd gang tim kiem nhung co che dac thii cua cac qua trinh sinh hgc ea ban nhat nham chi phdi toan bd the gidi sinh vat. Ddng thdi phit hi|n ra cac nhdm sinh vat cd tde dg sinh trudng nhanh. Tao la nhiJng sinh v|t bac thap nam trong su chu y do, vi chung khdng chi cd nhung ea che dac thii ma cdn sinh trudng va phat trien jat nhanh. Hang n5m cd den 200 ty tan chat hiiru ca dugc tao thanh tren toan the giai, trong sd do 170-180 tytSn la do tao tao thanh. Vi vay, trong moi trudng tu nhien tao la mat xieh dau tien trong chudi thiic an ciia thiiy vuc, ddng vai trd quan trgng trong viec tao nang suat sa cap bge mot cho thtJy vuc, khdng cd tao, khdng cd ngudn lgi thiiy san cho thuy vuc.
Trong moi trudng nhan tao, dien hinh la he thdng thiiy lgi hd Dau Tieng, khu he tao se phat triln theo chieu hudng nao, con ddng vai trd quan trgng lam thirc an tu nhien eho tdm ca trong thiiy vuc nira hay khdng, tat ca nhirng van de tren can kiem nghiem va giam sat. Vi vay vdi chuong trinh giam sat chat lugng nude he thdng thuy Igi hd Dau Tieng, trong dd cd viec quan trSc khu he th\rc v^t ndi tren he thdng nay da dugc tien hanh vao hai miia kho va mua trong nam 2012. Ket qua ciia bai bao lasd lieu da thu thap duge ve khu he thuc vat ndi tren 26 dilm thugc he thdng thiiy Igi hd Dau Tieng, nham xac djnh va danh gia muc dd da dang thuc v$t noi trong mdi trudng da co nhtrng tac dgnc tir con ngudi. Tir dd ed the cho thay dugc he sinh thai trong eac thuy vuc nhan tao lieu cd ben vung va hieu qua nhu nhirng thuy vuc mang tinh tu nhien hay khdng.
I. PHU'ONG PHAP NGHIEN ClTU 1. Ngoai thirc dia
Dia diem khdo sdt: Dirge thuc hien tai 26 diem thugc he thdng cdng trinh thiiy lgi ho Dau Tieng gom cac khu vuc: Kenli tudi, kenh tieu (kenh dao nhan tao) va long hd, kliu day man (khu vgc con mang ti'nh tu nhien).
Mdu djnh linh: Dugc thu bang ludi hinh chdp, co kich thudc mSt ludi la 20pm, ludi dugc keo khoang 50m chieu dai tren be mat, vdi tde do keo trung binh 0,5m/s.
Mdudinh hrgng: Dugc thu bang phuang phap lgc 60 lit nude qua ludi lgc hinh chop.
Cac mau thuc vat ndi dugc cd djnh ngay tai hien trudng bang dung djch formol bao hda sao cho nong do formol cudi cimg trong mau vao khoang 4%. Mau thu dugc danh dau, ghi chu gom ngay gid thu mlu, ky hieu va dia diem thu mau tren nhan. Ngoai ra, ghi chii thuc
^\a gdm cac dilu kien dja hinh, ddng chay, sinh eanh, eac thdng sd canh quan mdi trudng cung dugc ghi chep va md ta nhSm eung eSp them nhirng thdng tin gop phan ly giai, lam sing td kit qua phan tieh.
2. Trong phong thi nghiem
Cac mau thuy sinh vat dugc phan tich tai phdng thi nghiem Vien Ky thuat Bien, theo hai chi tieu djnh tinh va djnh lugng. Cac trang thilt bi dimg cho plian tich gim co kinh hien vi, dng dong, pipet, budng dim Scdgevvick Rafter, lamme, lammelle, thudc do chuyen dung,...
HQl NGHj KHOA HQC T O A N Q U O C V £ SINH THAl VA TAI NGUYgN SINH VAT L A N THLfS^
Mdu dinh tinh: Sir dung kinh hiln vi cd do phdng dai tdi da 1.000 lan de xac dmh cae loai trong mau. Cac mlu dinh tinh dugc xac dinh tdi loai va ghi chep vao bieu phan tich.
Mau dinh lugng: Dugc phan tieh theo phuang phap budng dim Sedgewick Rafter Cell c6 the tieh I ml, dem sd Iugng tl bao timg Ioai trong mau va quy ra sd lugng tren 1 lit.
Viec dinh danh thuc v|t ndi dugc dira tren ca sd hinh thai hgc (morphology) voi su trg giup cua cac tai lieu phan loai trong va ngoai nude nhu; Duong Dirc Tien (1996); Nguyen Van Tuyen (2003); Akihito Shirota (1966); Desikachary (1959),...
II. KET QUA NGHIEN CLTU
1. Cau true thanh phan loai >
Kit qua phan tich mlu thue vat ndi (TVN) t?i 26 dilm khao sal thudc he thdng thuy Igi hh Dku Tilng nam 2012 da ghi nhan duge 329 Ioai va dudi loai thudc 125 chi, 69 hg, 35 bg, II Idp, 7 nganh tao la: Tao Lam {Cyanophyla), tao Vang {Xanlhophyla), tao Vang anh {Chrysophyla), tao Silic {Bacillariophyta), tao Luc {Chlorophyta), tao Mat {Euglenophyta) va tao Giap {Dinophyta). Trong dd: Nganh tao Luc co sd Iugng loai cao nhat, thap nhat la nginh tao Vang, tao Vang anh va tao Giap (bang 1).
Trong tong so 125 chi ghi nhan dugc, cac chi cd nhilu Ioai nh5t la: Staurastrum (79 Ioai), Cosmarium flS Ioai), Scenedesmus 06 loai), Oscillatoria (\2 loai), Closterium (\\ Ioai), Phacus (\ I Ioai), Euglena {\Q Ioai), Coscinodiscus (^ Ioai), Pedia.sirwn (1 loai), Slrombomonas fl loai). Microcystis (6 loai), Tetraedron (6 loai), Micrasterias (6 loai), Surirella (6 loai). Rat nhilu chi cd dudi 6 Ioai va co khoang 73 chi chi ghi nhan dugc 1 Ioai nhu: Chroococcus, Arthrospira, Skeletonema, Thalasslonema, Xanihldlum, Ceralium,...
Do phgm vi khao sat rgng, tren nhieu Ioai hinh thiiy vyc khac nhau, nen eau triic thanh phan loai TVN thudc he thdng thity Igi hd Dau Tieng ghi nhan dugc kha phirc tap. Cau triic loai bao gdm nhirng Ioai mang ngudn gdc nude nggt dae trung thudc Chlorophyta, Euglenophyta phan bd xen lan vdi eac loai mang ngudn gde bien di nhap sau vao ndi dja nhu Bacillariophyta, Dinophyta. Vai su phan bd xen lan giua cac Ioai mang dac tinh sinh thai khac nhau nay cho thiy, mdi trudng nude mit d mgt sd cac diem khao sat bi xam nhap m^n vdi ndng do mudi kha thap (khu day man).
Cau true thanh phan loai TVN thugc he thong thuy loi ho Dau Tieng TT
1 2 3 4 5 6 7
Nganh tao Cyanophyta (tao Lam) Xanthophyta (tao Vang) Chrysophyla (tao Vang Snh) Bacillanophyta (tao Silic) Chlorophyta (tao Luc) Euglenophyta (tao Mit) Dinophyta (tao Giap)
Tong
Lap 1 1 2 3 2 1 1 11
BQ 3 1 2 16 9 2 2 35
Hp 9 2 4 23 23 3 6 69
Chi 22 2 4 30 56 5 6 125
Loiii 48
2 6 65 169 30
9 329 Tinh chung tren toan b^ sd Iugng mau thu duge, tdng sd loai TVN vao miia khd va miia mua gin tuang duang nhau (miia khd: 285 Ioai, miia mua: 238 Ioai). Thu tu da dang cae nganh
QI lor.HlKHOA HQC TOAN QUOC V£ SINH THAl vA TAI N G U Y £ N SiNH VAT LAN THlJ 5 thav dii, t30 Lue van chiem uu the so vdi cac tao khac; ke tiep la tao Silic, tao Lam,...
tao ^°jSj^ j^Q Y^ng. Tuy nhien, sd Iugng Ioai tao d miaa mua thip so vdi miia khd, tong thanh
^^•^ ^ ^- oiam 47 loai; trong do, giim manh nhat la nganh tao Luc (23 Ioai), cac nganh tio cdn y. .A^„ ^fiu Virc khdo sdt: Tdng sd Iugng Ioai ghi nhan dugc d cac khu vuc la kha eao, dao
. 156-222 loai. Trong do, tai khu vuc day man cd s6 loai cao nhit (222 loai), thap nhat la ih" uc long hd (156 loai). Cac khu vyc cdn lai cd sd loai kha eao va dn djnh, vdi khu vuc kenh
' • ia 215 loii va khu vyc kenh tieu ed 162 loii (xem hinh).
Vao miia mua, hiu het cac kenh tudi va kenh tieu deu ddng Iai, ngudn nude khdng dugc 1 u thong, cong vdi cac ngudn xa tryc tiep tir khu dan cu, hoat ddng ndng nghi?p lim cho him I cac chat dinh dudng tang cao, tao dieu kien eho mdt sd nhdm Ioai phat trien manh vl mat do lin at cac loai khac, din den miie do da dang tai khu vyc dd giam xudng. Dieu nay giii thich vi sao so lugng loai TVN thudc he thdng thuy Igi hd Dau Tieng vao miia mua thip han so vdi miia kho d i5t ca cac khu vyc khao sat.
Tai khu vyc diy man, la nai thudng xuyen bi xam nhap m§n bdi trieu cudng nen ghi nhan duae sy xuat hien eiia ca nhtmg Ioai nude nggt dac trung phan bd xen Ian vdi cac Ioai mang ngudn nSc bien thich nghi trong mdi trirdng nude lg. Do dd, thanh phan loii tao nai day eao hon han so vdi cac khu vyc khac. Sd lugng Ioai ed su khae biet giiJa cac thdi diem trieu cudng va trieu kiet nhung khong dang ke, d thdi dilm trieu kiet cd sd loai dat dugc cao han, cd the la do vio thai diem Uilu cirdng cd ham Iugng chat la limg cao, cae chat dinh dudng khd luu thdng. tich tu gi>
nhiem ban cue bo. chat lugng nude trong thdi diem nay kem han da tac dong dang ke den sy phan bo cua tao, dHn den mirc dg da dang Ioai giim sut di so vdi thdi diem trieu kiet (xem hinh).
mm m
I
Tuii. TiiitianiiiilT.itii TiiiiTiniHiMiia Mi>a nnuiq Miia Miia QIKII? Mo.iklio \ Miiaiiiii.-i kit.t
Hinh. Sd hrgng lodi ihirc vdl ndi lgi cdc khu virc khdo sal
2. Mat d9 phan bo va loai uu the
M^t dp phdn bo: Mat do tl bio TVN tai cae diem thu mau thudc he thong thiiy Igi hd Dau Tieng ghi nh^n dugc trong nam 2012 dat gia tri dao ddng tir 119-1.328.736 te bio/lit; trong do dgt khao sit miia mua ghi nhan cd mat do tio dao ddng tir 119-140.403 tl bao/lit, miia kho dat gii trj cao han: 417-1.328.736 tl bao/lit (bang 2),
Xet theo khu virc: Dat gia tn cao nhat tai khu vyc thupc kenh tieu vao miia khd va thap nhat la khu day man tai thdi diem trieu kiet d miia mua.
Hau het cic diem thu miu cd mat dd uu the tucmg ddi cao, trung binh dat tren 10 te bao/lit.
MOt sd diem khic la kha thap (<10'' tl bio/iit) nhu: Cdng sd 3 tren kenh Tin Hung, kenh tudi NIO (khu vyc kenh tudi); ciu Dirc Hda, cau Rach Tra, cau Phii Cudng, eau Bin Lire (khu day man).
HQl NGHj KHOA HQC T O A N Q U O C V £ SINH THAI VA TAI N G U Y £ N SINH VAT LAN T H l ^ So sdnh giira hai miia: Mat dd tl bio TVN tron^ dgt khao sat miia mua giini '"^"J.^°'' ^°
Iugng Idn so vdi miia khd, giam trung binh tren lO' te bao/lit, rieng vi tri kenh tudi N5 (khu vuc kenh tudi) vi rach Tiy Ninh (khu vyc kenh tieu) giam tren 10'* te bao/lit.
Trong cic thiiy vyc, tio ddng vai trd chii chdt trong thi gidi sinh vat, lim cho chu trinh vgt chit trong cac thiiy vuc dugc khep kin. Khi thuy vyc mat di mgt nhdm sinh vat nao deu anh hudng den do da dang ciia thu> vuc. Dieu nay de diln ra d cac thuy vyc nhan tao, nhu trong he thong kenh tudi va kenh tieu, khu he ddng vat day hau nhu hi biln mat, dae biel la cic nhdm an lgc \a an mim ba huu ea. Sy ving mat cic nhdm an lgc, din din ham Iugng chit dinh dudn|
khdng dugc tieu thu ngiy mgt tang Ien, da tao dieu kien cho nhom tao phat trien manh ve sdlugng.
Tir bang 2 cho thiy. mat do tl bio TVN d khu vyc Idng hd va diy man (thuy vyc mang tinh ty nhien) dat gia iri thip vi biln ddng dn dinh hon so vdi khu vyc kenh tudi, kenh tieu (thiiy vyc nhan tao). Dilu nay thi hien khu he TVN d nhimg thiiy vue cdn mang tinh ty nhien phat trien dieu hda, ben vOng han so vdi cac thiiy vyc nhan tao.
Bdng 2 Dao dono mat do te bao TVN tai cac khu vyc khao sat
^ ^ ^ ^ ^ Khu vyc Thcri gian ^ ^ ^ ^
Mua l(ho
I^ua mira
Kenh t u ^ i ( t i bao/h't) 101 183 1 135.808 405 69.170
Kenh tieu ( t l bao/lit)
1.691 1.328 736
1.170 13.806
Long hd ( t l bao/lit)
62.000 544.347 6.429 140.403
D i y m | n T r i l u cuo-ng Trilu l<i?t
( t l bao/lit) ( t l bao/lit) 417
780.806 244 8.629
1.436 426.124
119 13.491 Lodi uu the: Thanh phan loii phat trien chiem uu the thay ddi khdng dang ke giira hai miia, miia kho ehii yeu la nhom loii tio Silic va tao Luc chiem uu the vio miia mua chii yeu la cac Ioai tio Lam, tio Vang anh, tao Silic va tao Lue vdi mirc do uu thi dao ddng tti 15,3-93,0%
(bang 3). Trong dd, eac loai tao Lam chiem uu the tai phin Idn cic diem thu mau (17/26 diem), cd nhieu diem dat gia trj uu thi cao (> 50%), tham chi la tuyet ddi (> 80%) nhtr: Cdng so I tren kenh chinh Ddng (khu vyc kenh tudi), edng sd 2 trong Idng hd Diu Tilng (khu vue idng hi), rach Tay Ninh (khu vyc kenh tieu), ciu Binh Phudc (khu diy man). Dilu nay cho bilt chat Iugng mdi trudng nude tai khu vyc quan trie da ed hien tugng nhiem ban eao, him lugng dinh dudng ldn, tao dieu kien cho mdt sd Ioai tao Lam phit trien manh ve mat dg dan din hien tugng mat can doi trong khu he thyc vit ndi.
Loai iru the va ty le % ciia TVN thudc he thdng thuy loi hd Dau Tieng Bang 3
Khu v y c kenh tirdi Otm
Nl N2 N3 N4
Mua kho Loai uu t h i Microcystis aeruginosa Coenococcus planctonicus Coenococcus planctonicus
Ty Ie % 45.8 43.7 21.7 Coenococcus planctonicus \ 84,7
Mua mu'a Loai iFU thk Desmidium aptogonum Desmidium aptogonum li^icrocyslis aeruginosa Coenococcus planctonicus
T » l ^ % 77,7 38,9 57.9 45,7
u g NGHI KHOA HQC TOAN QUOC V6 SINH THAI VA TAI NGUYEN SINH VAT U N THLr 5
Dtiti
1S~
C3.1
Eltiti T1 T2 T3 T4 T5
Khu v y c kenh t\tm Miia kho
Loai i n j the nnenococcus planctonicus nctvosphaenum pulchelium jyjcrocysfo aemginosa Botryococcus braunii
Ty le % 78,9 20,2 38,8 33,6
Miia mya Loai y u the Spirogyra pmtilica Anabaena spinoides Anabaena spiroides Lyngbya sp
Ty H % 16,5 93.0 60.1 49.4 Khu v y c kenh tieu
Miia kho Loai y u the Coenococcus planctonicus Microcystis aeruginosa Melosira granulate Melosira granulate Melosira granulate
Ty le % 30,3
63 77,5 61,6 34.7
Miia mya Loai y u t h i Planktothnx sp.
Planl<tothnx sp Melosira granulate Synura adamsii Osciltatona tenuis
T y l e % 41.3 86.9 16.3 27.7 45.1 Khu VU'C long hd
Otm C12 C2.2 C3 2
Mua kho \ Miia mya Loai y u the
Dinobryon sedulana Microcystis aeruginosa Microcystis aeruginosa
Ty I I % Loai yu the 28,4 1/Inatiaena sp/ro/des 53,6
51.2
Anabaena spiioides Coenococcus planctonicus
Ty le % 80,1 39,6 63,5 Khu vyc day man
Thai diem t r i l u cu'O'ng Dtm
M1-L M2-L M3-L M4-L M5-L M6-L M7-L
Miia kho Loai y u t h i Melosira granulate var angustissima Melosira granulate var. angustissima Melosira granutata var. angustissima Melosira granulate var. angustissima Ptanldothnx sp.
Melosira granutata Adhrospira massadii
Ty If % 50,8 45,4 62,9 73,1 44,1 57.6 60.9
Miia mi^a Loai y u the Osclllatona sp Osclllatoda tenuis Melosira granutata Melosira granulela Volvox aureus Dinobryon sedulana Melosira granulate
Ty 1? % 41 40,6 67,5 74,1 19,3 27,6 33,3 Khu VU'C day man
Thai diem trieu kiet Dtm
MIR M2-R M3-R M4-R M5-R Me-R M7-R
Miia kho Loai y u the Melosira granutata vat angustissima Melosira granulate vat angustissima Melosira granulate vat angustissima Melosira granulate var. angustissima Oedogonium sp.
Osciltatona tenuis Adhrospira massariii
Ty le % 61.2 69.5 56.8 50.5 72.1 26.1 47.7
Miia mya Loai y u the Plantitothncoides adenuata Osclllatona tenuis Melosira granulate Melosira granulate Dinobryon sedulana Snowella litoralis Oscillatona sp
Ty If •/.
50,4 53,5 80,1 39,1 35 15.3 30.9 III. KIET LUAN
^ Ket qua khio sal khu he thiiy sinh vat tai cic diem thu mau thudc he thdng thiiy Igi ho Dau Tieng trong nim 2012 phong phu va da dang, da ghi nhan dugc 329 loai thude 7 nginh; trong do khu vyc kenh tudi ghi nhin dugc 215 Joii, khu \yc Idng hd c6 156 loai, khu vuc kenh tieu
HQI NGHj KHOA HQC T O A N Q U Q C V £ SINH THAl VA TAI N G U Y £ N SINH VAT L A N T H O ^ J dat 162 loii va khu vyc diy man la 222 loii. Phan Idn cae loai ghi nhan dugc co gia *"•'f''"'?
duang cao (tao Silic, tao Luc), ehiing li nguon thuc an ty nhien cua tdm, cua. ca; ben c?nn o la mgt sd loai tao Lam dge, cd kha nang tiet dge td gay hai cho mdi tnrdng.
Cau true thanh phin loii it cd sy khae biet giira hai dgt khao sat; sd Iugng loii, "lat dg te bio hien dien tai eae diem thu mau d miia khd cao han so vdi miia mua. Tuy nhien, muc dg uu the cua cac Ioai tio vio miia khd lai thip han miia mua.
Thanh phan loai uu thi chii yeu li cac loii tio Lam, tao Vang anh, Jao Silie va tio Liic^ It cd sy thay ddi giira mua khd va miia mua. Cac loii tao Lam chilm uu the t^i phan Idn cac diem khio sat, nhilu dilm dat gia trj uu thi cao (> 50%), tham chi li tuyet ddi (> 80%) nhu: Cdng so I tren kenh chinh Ddng, cdng so 2 trong long hd Dau Tilng, r^ch Tay Ninh, eau Binh Phudc.
Dilu nay cho bilt chit Iugng mdi trudng nude nai day da bj nhilm ban cao va cd hien tugng phat trien mit can ddi trong khu he thyc vat ndi.
Tu nhii'ng biln ddng vl so loii, mat 6^ te bio va loii uu the tai cac khu vyc khio sat thugc he thdng thuy Igi ho Diu Tilng eho thay, khu h? TVN d nhQng thiiy vyc cdn mang tinh tu nhien phat tnen bin viing han so vdi cae thuy vyc nhin tao.
TAI LIEU THAM KHAO
Akihito Shirota, 1966. The plankton of South Viet Nam-Fresh water and Marine Plankton. Overseas Technical Cooperation Agency, Japan. 462 pp.
Cornelius L. Weber, 1971. Aguide to the common Diatoms at Water Pollution Surveillance System Stations. U.S. Enviromental Protection Agency.
Desikachary T, V., 1959. Cyanophyta. Published by Indian council of AgricuUure research new Delhi, 685 pp.
Nguyen Thi Thu Lien, 2007. Planktic cyanobacteria from fi-eshwater localities in Thuathien-Hue province, Viet Nam. University of Copenhagen. Ph.D. Thesis, 192 pp..
5. DmmgDirc Tien, 1996. Phan loai vi khuan lam d VietNam. NXB. Nongnghiep, 503 trang.
6. Dirong Dirc Tien, V6 Hanh, 1997. Tao nude nggt Viet Nam, Phan logi bg tao luc. NXB. Nong nghiep, 502 trang.
Nguyen V3n Tuyen, 2003. Da dang sinh hpc tao trong thuy vyc ngi dja Vi?t Nam. NXB. Nong nghiep, 498 trang.
Yamagishi T. andm. Akiyama, 1994. Photomiccrographs of the Freshwater Algae. Uchida Rokakuho Tokyo Japan, Volume I2and 14.
AN ASSESSMENT OF PHYTOPLANKTON OF DAU TIENG IRRIGATION SYSTEM IN 2012
HUYNH VU NGOC QUY, DO THI BICH LOC
SUMMARY
Two field surveys on Phytoplankton were conducted in 2012 at 26 sitesof Dau Tieng irrigation system.
Resulted from our study, a total of 329 species of phytoplanktonbelonging to 125 genera. 69 families, 35 orders, 11 classes of seven phyla were recorded. The species composition included both types of species origins- The freshwater origin (e.g , species of Chlorophyta and Euglenophyta) and the marine origin which invaded into inland waters (e.g.. species of Bacillariophyta and Dinophyta). Among four surveyed areas, the Day Man preventive saltwater area has the highest species diversity and the drainage channels has the lowest species number. Species richness of phytoplankton is higher in dry season than in rainy season, however, the structure of species composition and the number of predominant species are noi significantly changed