Tieu ban: C 6 N G NGHE SINH HOC BlfeN VA MOI TRU'6'NG 4 3 1
NANG SUAT SINH HOC SO CAP CUA THlTC VAT NOI VA DIEU KIEN SINH THAI LIEN QUAN 6 VT/C NlJ6C
NHA TRANG - NHA PHU (TKHANH HOA)
Nguyen Hiru Huan, Nguyen Tac An va Bui Hong Long Vien Hai duang hpc, Vien Khoa hpc vd Cong nghe Viet Nam
I. ua DAU
Nam fren khu vyc Nam Trung bg, vdi dieu kifn dja ly, khi hau,... thuan lgi, frong do co ngu6n lgi thiiy san phong phu, da dang, vyc nude Nha Trang - Nha Phu rat thuan lgi de trien khai nhieu boat dgng kinh te bien, dac biet la: khai thac va nu6i fr6ng cac loai hai dac san, du Ijch sinh thai, ...121. Do hgi ty nhieu dieu ki^n thuan lgi cho sy phat frien da nganh nen da c6 sy canh tranh giira cac nganh kinh te frong quy hoach phat trien. Van de dat ra la: lya chgn va quy hoach nao la phii hgp cho vyc nude Nha Trang - Nha Phu de dam bao phat trien ben vimg?. Vdi bat ky mgt sy lya chgn nao thi: dieu kifn thuan lgi cho phat frien (hay tiem nang) va anh hudn^
frd lai eua eac boat dgng kinh te dugc chgn lya (hay tac dgng) den m6i trudng la nhiing yeu td mang tinh quyet djnh trong qua trinh xem xet, chgn lya quy ho?ich phat trien kinh te - xa hgi.
D6i vdi mgi quy hoach cac vyc nude ven bd, nghien cihi d$c trung nang suat so cap co mgt vai fro kha quan frgng bdi nd kh6ng nhung la co sd de xay dyng giai phap khai thac tiem nang nang suit sinh hgc thuy vyc ma con gop phan danh gia tinh frang thiiy vyc, kha nang chuyen hoa vat chat frong h? sinh thai bien ven bd. Trong khu6n kh6 dy an hgp tac Vi^t Nam - Na Uy (NUFU): "Ben virng nuoi trong thuy san ven bien", giai doan 2 (2007 - 2011), bai bao nay trinh bay nhirng net dac frung co ban ve nang suat sinh hgc so cap va nhimg yeu t6 sinh thai lien quan d vyc nude Nha Trang - Nha Phu tren co sd ngu6n dir lifu thu thap dugc.
II. DIA DIEM VA PHUONG PHAP NGHIEN CU*U
L Dja diem v^ thdi gian thu mau
Khu vyc nghien curu thugc vyc nude Nha Trang - Nha Phu, tinh Khanh Hoa, vdi so d6 fram thu mlu dugc the hien fren hinh 1. S6 lieu thyc hien bai bao nay chu yeu tir eac chuyen khao sat dugc tiln hanh vao thang 07/2008 va thang 06/2009 (miia kho) va vao thang 10 va thang
12/2008 (miia mua).
432 Tuyln tgp HQi nghj KHOA HQC TOAN QUOC v £ SINH HQC BI^N v A PHAT TRI^N B £ N V&Nft
Hinh 1. Ban dd tr^m thu mSu vyc nwac Nha Trang - Nha Phu
2. Phvong phap do dac, xur ly so lifu v^ tinh toan
- Cac ylu to vat ly: Do bSng CTD hi?u SAIVAS (Na Uy).
- Oxi boa tan: Phuong phap Winkler /10/.
- Nang suat sinh hgc so cap: Phuong phap gia so oxi frong binh den frSng.
- Chlorophyll-a: Phuong phap quang ph6 (chilt frong dung m6i aceton 90% va so may quang ph6 UV-Visible) 1101.
£\n.i
mau fren
Tilu ban: C 6 N G NGHE SINH HQC BifeN VA M 6 | TRLfONG 433
- Mu6i dinh dudng: Phuang phap so mau (len mau bang cac h6n hgp tao phiic va so mau bang may quang ph6 kha kiln UV- Visible) /lO/.
- Vat chat lo limg (TSS): phuang phap frgng lugng IIOI.
Toan bg dir lieu thu thap dugc xir ly fren cac phan mem thong ke th6ng dyng: Excell va SPSS for 'Windows, ban do fram thu mau dugc xay dyng fren Maplnfo va Surfer.
i n . KET QUA NGHIEN ClTU VA THAO LUAN
\. Phan bo nang suat sinh h9c so cap
Ket qua nghien cihi cho thay, nang suat sinh hgc so cap vyc nude Nha Trang - Nha Phu bien dgng manh theo thdi gian va kh6ng gian. Birc tranh khai quat phan b6 nang suit so cap fren toan vimg cung nhu timg khu vyc theo miia dugc the hi?n d bang 1, hinh 2a va 2b.
Trong miia khd, nang suat th6 trung binh tai vyc nude Nha Phu cao hon vyc nude Nha Trang (vyc nude Nha Phu: dao dgng frong khoang: 30,00 - 254,00mgC/m\ngdy, ti-ung binh:
127,56 ± 91,39mgC/m^/ngdy; frong khi d6, vyc nude Nha Trang: dao dgng frong khoang: 27,00 - 3:46,40mgC/m^/ngay, trung binh: 104,29 ± 11,10mgC/m'/ngay). Nang suat th6 cao tap trung d khu vyc nudi frong thiiy san phia Tay Nam dam Nha Phu, vimg ven bd cira s6ng Cai, s6ng Cira Be va khu vyc Tay Nam Hon Tre (vdi nang suat th6 tang m$t cd 200mgC/m^/ngay). Sy hinh thanh cac trung tam nang suat cao nay cd lien quan din ngudn dinh dudng dugc cung cap cho vyc nude tir cac boat dgng kinh te - xa hgi xung quanh (nu6i thiiy san, cang ca, nha may chi bien, cac khu dan eu tap trung) cung nhu tir ngu6n thai ciia eac khu vyc lan can qua cira s6ng.
Bang
Y e u t d
Nang suat tho (mgC/m^/ngay)
N§ng suat tinh (mgC/m^/ngay)
C u d n g dp ho hap (mgC/m^/ngay)
H$ s6 P/R
1. Nang sudt sinh hpc scr cSp vyc nu'O'c Nha Trang - Nha Phu
Khu v\jfc Nha Phu
Nha Trang
Nha Phu
Nha Trang
Nha Phu
Nha Trang
Nha Phu
Nha Trang
Gia trj Dao dong Tmng binh
Dao dong Trung binh
Dao dong Trung binh
Dao dpng Trung binh
Dao dong Trung binh
Dao dpng Trung binh
Dao dpng Trung binh
Dao dpng Trung binh
Mua kho 30,00 - 354,00 {n=24)
127,56 ±97,39 27,00 - 346,40 (n=29)
104,29 ±77,70 -163,50-192,70 (n=24)
-19,73 ±107,29 -99,00 - 237,30 (n=29)
29,72 ± 7 6 , 1 6 54,00 - 300,00 (n=24)
147,29 ±58,90 21,00-179,90 (n=29)
74,57 ± 4 8 , 1 4 0 , 1 9 - 2 , 3 9 (n=24)
0,99 ± 0,79 0 , 3 7 - 4 , 0 0 (n=29)
1,80±1,11
Miia m u ^ 33,20 - 527,70 (n=20)
148,08 ±114,87 28,50 - 503,80 (n=25)
152,33 ±151,59 -211,80-288,10 (n=20)
29,83 ±106,20 -139,90-389,30 (n=25)
21,68 ±124,80 57,70-269,10 (n=20)
118,25 ±58,99 37,90 - 440,80 (n=25)
130,65 ± 9 4 , 8 2 0,21 - 2 , 4 1 (n=20)
1,30 ± 0 , 6 9 0,2 - 5,00 (n=25)
1,29±1,14
Trong miia mua, gia frj trung binh nang suat so cap tren 2 viing deu cao hon frong miia kho nhung khong cd sy khac bi?t ro rang ve nang suat th6 giira 2 vyc nude. Tai Nha Phu, nang suit tho dao dgng frong khoang: 33,20 - 521,lOmgC/m^/ngay, tnmg binh: 148,08 ±
\\4,SlmgC/m^/ngdy\ trong khi do, d6i vdi vyc nude Nha Trang, nang suit th6 dao dgng frong
434 Tuyln t|ip H$i nghj KHOA HOC TOAN QUOc V£ SINH HQC B | £ N V A P H A T TRifeN BfeN V&NR
khoang: 28,50 - 503,SOmgC/m^/ngay, fr\mg binh: 152,33 ± \5\,59mgC/m^/ngdy. Nhu v?y, thyc te cho thay, nang suat th6 trong miia mua cao hon trong miia khd. Ket qua nay lien quan den ngu6n dinh dudng tir dat lien cung cap cho cac vyc nude frong miia mua Idn hon frong miia kh6
>i
SI
10815
^J ' \
s«D{ Cii Q ; ^
s*°««J*^
109.2
^
108.25 108.3
: / - H ^ -
yy
^^HmLiTk' j / / \ t J " ^ /^"*"^
^w~/
1
^ \4 / ~
/ / y—
( • ( ^
\ V » . HAoTre . f u
108-15 108.2
108.25 108.3
TANG MAT (surface layer) TANG DAY (bottom layer) Hinh 2a. Phan bd nang suSt sc cdp trong mua khd
10B.25 109.3
10915 109.2 109.25 109.3
TANG MAT (surface layer) TANG DAY (bottom layer) IHinh 2b. Phan b6 nang su§t %o cdp trong mua mu'a
Nhin chung, gia frj nang suat thd vyc nude nghien ciiu cao ban nang suit th6 ghi nhan dugc d vimg nude froi manh Nam Trung Bg (60,22 ± 45,21mgC/m^/ngay), vimg thim lye dja (dg sau
Tieu ban; CONG NGHE SINH HOC BI^N VA M 6 I TRLfONG 435
<200m: 46 ± \6mgC/m /ngay), nhung thap hon nang suat tho viing dam pha, cira song ven bd Binh Dinh (253,87 ± 130,12mgC/m^/ngay frong miia kho va 486,37 ± 333,25mgC/m^/ngay frong miia mua), vimg chau th6 Mek6ng (156,74 ± 59,39mgC/m^/ngay frong miia kh6 va 258,20 ± 206,43mgC/m^/ngdy frong miia mua) 13, 4, 5, II.
109.15 1092 109.25
109.15 109 2 109 25 109 3
109.15 109.2 10925
109,15 109.2 10925 1093
T A N G MAT (surface layer) TANG DAY (bottom layer) IHinh 3a. Phan bd cu>ang dp ho hap trong miia khd
108.2 109.25 109.2 109.25
109.15 109.2 10925 109 3
TANG MAT (surface layer) TANG DAY (bottom layer) Hinh 3b: Phan bd cu'd'ng dp ho h i p trong mua mu'a
Tuyen tgp HQi nghj KHOA HQC T O A N Q U 6 C Vfe SINH HQC B I £ N V A PHAT TRI^N BtH V&NG
436
Ciing nhu nang suat th6, cudng do bd hap frong viing Nha Phu cao hon nhieu so vdi viing Nha Trang frong thdi ky miia khd, nhung trong miia mua khdng cd sy sai khac ro rpt (bang ])•
cudng do h6 hip ciing tap trung cao vao cac khu vyc nhan cac ngu6n thai (hinh 3a, 3b). Rieng.
tai khu vyc cira s6ng Cai (Nha Trang), cudng dg bd hap miia khd khdng cao nhung frong miia!:
mua d tang day ciing xuit hipn cudng dg bd hip cao. Do ddng chay miia kho yeu nen nguon thai^
chi cd anh hudng trong khu vyc ngi ddng, frong khi frong miia mua thi chiing da dugc chuyen'
din khu vyc cira sdng ven bd vjnh dan tdi cudng dp hd hap eua vyc nude kha cao. | Hp so P/R (nang suit thd/ho hip) frong miia kho dao dgng frong khoang: 0,19 - 2,39; trung 1
binh: 0,99 ± 0,79 doi vdi vimg Nha Phu; frong khoang: 0,37 - 4,00; tiimg binh: 1,80 ± 1,11 doi;
vdi vimg Nha Trang. Trong miia mua, he so fren dao dgng trong khoang: 0,21 - 2,41; frung binh:
1,30 + 0,69 doi vdi vimg Nha Phu; frong khoang: 0,2 - 5,00; framg binh: 1,29 ± 1,14 doi vdi' vimg Nha Trang. Trung binh kit qua trong ca 2 miia cho thay: qua trinh tao thanh hihi ca cSn bing hoac Idn hon qua trinh phan ra di dudng. Dieu nay chung td qua trinh quang hgp m ^ hem qua trinh hd hip va do v^y, cac quan xa sinh vat d day sdng chu yeu nho vat chit ty t?io frong • qua trinh ho^t dgng ty dudng cua thyc vat don bao. Cac san pham quang hgp cd kha nang ddp ling nhu ciu cua boat dgng phan ra dj duong, ngu6n nang lugng co sd dii sure cung cip cho cdc boat dgng sdng ciia he. Dieu nay cung pho bien d cac hp sinh thai dam, pha va eua sdng ven bien nhiet ddi. Dac trung nay cho phep de xuit vipc xay dyng phuang an khai thac mpt each tot nhit tilm nang nang suit sinh hpc ciia vung frong qua trinh sii dyng vyc nude.
2. Phan bo chlorophyll-a (Chl-a)
Nhin chung, n6ng dp Chl-a frong miia kh6 thap hon so vdi mua mua, d vyc nude Nha Phu cao hon nhilu so vdi vyc nude Nha Trang (bang 2, hinh 4a va 4b).
Bang 2. Ham lu>7ng Chl-a trong nu'dv
Y6ut6
Chl-a (mg/m^)
Khu vyc
Nha Phu
Nha Trang
G l i trj Dao dpng
Trung binh
Dao dpng
Trung binh
Mua kho 0,11 -6,76(n =
24) 2,22 ±2,17 0,18-4,46 (n =
29) 1,12±1,08
Mua mu^
0,83-8,31 (n = 20) 2,79 ± 2,01 0,43 - 4,36 (n =
25) 1,26 ±0,92
Tilu ban: CONG NGHE SINH HQC BI^N VA M 6 | TRLTCTNG 437
TANG MAT (surface layer) TANG DAY (bottom layer) Hinh 4a. Phan bd Chlorophyll -a trong mua khd
109.15
1 •**!
S6og Cii ^
Siai Biy 109.2
^ ^ ^ ^ ^ N
^^k
V^
109.25 100,3
( . ' ^ '
• \ —
/
\ ^ HdoTre r
N.
^
109.15 109 2 109.25 109.3
109-15 109.2 109.25 109.3
109.15 109-2 109.25 1093
TANG MAT (surface layer) TANG DAY (bottom layer) Hinh 4b. Phan bd Chlorophyll -a trong mua mu'a
Biic tranh phan bo nong do Chl-a fren toan vimg ciing the hien nhung khu vyc cd nong dg Chl-a cao la nhirng khu vyc nuoi thuy san, tap tiring cac boat dgng kinh tl - xa hgi tren vimg ven bd Khanh Hoa. Co the nhan thay, hau het cac vimg c6 n6ng dg chl-a cao deu cd nang suit so cip cao (hinh 4a va 4b). Tuy nhien, do chiu sy chi phoi ciia nhieu ylu to khac nhu: anh sang, dinh
438 Tuyen t§p HQi nghj KHOA HQC T O A N Q U 6 C V £ SINH HQC BI^N vA P H A T TRifeN B £ N Vj/NG
dudng, kha nang xao frgn khoi nude neii kh6ng phai liic nao nong dg chl-a cao deu cd so cip cao. Quan he giiia nang suit so cap va n6ng dg chl-a the hipn d hinh 5.
nang suit
400 ^ JSO
%, -200
S^ 150 i lOO
SO
• 6 ' . 9 a 3 1 n ( I ) + 1 2 0 . 0 1 R^ - 0 . 4 8 8 4
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C'bl-H Oitg iir'}
Hinh 5. Quan hp giu'a nang suit thd v^ ndng dp Chi -a
3. Muoi dinh dir&ng nito va photpho
Dac trung noi bat nhit cua muoi dinh dudng d vyc nude Nha Trang - Nha Phu la, frong khi nong dp mu6i dinh dudng nito v6 co d Nha Phu frong miia mua Idn hon nhieu so vdi miia kho thi tai Nha Trang, sy sai khac n6ng dp dinh dudng nito giira 2 miia la khdng dang kl (bang 3).
Tuy nhien, fren toan eye thi, ndng dp mu6i dinh dudng trong miia mua cao hon miia kh6 tren ca hai vyc nude nghien ciiu va khdng cd gia fri vugt qua gidi ban Tieu chuin chat lugng nude thiiy
sinh va nudi thiiy san/I/. ,
i«
Bang 3. Ndng dp mudi dinh du'd'ng trong nu'6'c i
Y6ut6
DIN (mg/rri')
DIP (rrig/m^)
Ty s6:
N/P
Dja di6m
Nha Phu Nha Trang
Nha Phu Nha Trang
Nha Phu Nha Trang
Gid trj Dao d$ng Trung binh
Dao dOng Trung binh
Dao (JOng Trung binh Dao aOng Taing binh
Dao dOng Trung binh Dao dOng Trung binh
Mua kh6 30,00-147,00 (n= 24)
64,24135,31 27,00- 173,10 (n= 29)
58,17 ±38,48 7,50-21,90 {n= 24)
11,08 ±4,03 3,60-16,60 (n= 29)
8,93 + 47.50 7,54 - 35,38 (n= 29)
15,65 + 10,34 5,50-31,23 (n= 29)
14,91 ±7,17
Mua mira 39,20 - 350,30 (n= 20)
147,54 ±117.05 31,00-322,50 (n= 25)
63,06 ± 64,00 10,40-26,90 (n= 20)
17,39 ±6,39 10,40-26,60 (n= 25)
15,03 ±5,06 3,56 - 55,80 (n= 25)
21,68 ±19,67 2,66-16,99 (n= 25)
7,21 ±4,32
QCVN- 2008 ni
NH/:
100,0n
200,or)
Ghi chii: (*): QCVN-lO/2008/BTNMT: Quy chudn ky thudt qudc gia vi chdt luang nude bien ven bd (Tieu chudn diing cho nuoi trong thuy san vd bao ton thuy sinh).
(**): QCVN-08/2008/BTNMT: Quy chudn ky thuat qudc gia vi chdt lupng nude m^t (Fieu chudn diing cho bao ton thuy sinh).
Xem xet fren phuong dipn can bang vat chat cho thiy, trong miia khd, ty le N:P d ca 2 vung xip xi nhau va gan bang ty so Redfield (N:P = 16:1). Kit qua nay chirng td trong miia khd ca 2
Tilu ban: CONG NGHE SINH HOC BI^N VA M 6 I TRUd'NG 439
vyc nude deu mang dac trung dinh dudng cua m6i trudng nude bien. Con frong miia mua, co sy khac biet nhau rd rpt giira 2 vyc nude: nito la yeu to gidi han vyc nude Nha Trang trong khi phot pho la yeu to gidi ban d vyc nude Nha Phu. Nhu vay, trong miia mua vyc nude Nha Phu chiu chi phoi manh cua ngudn dinh dudng mang tinh lye dja, trong khi do vyc nude Nha Trang van mang dac trung dinh dudng cua m6i trudng nude bien /8, 91.
4. Vat chat lo lung (TSS)
Nong do vat chat la lung trong vnng nghien ciiu bien dgng rat Idn theo khdng gian va thdi gian. Sy khac bipt ndng dg vat chat lo limg trung binh giira Nha Trang va Nha Phu, giira miia kh6 va miia mua kha rd rang (bang 4). Trir 1 s6 tram khu vyc khu vyc dinh dam Nha Phu va cira sdng Cai, song Be frong thdi ky miia mua, phan Idn cac gia trj ghi nhan dugc deu nam trong gidi han cho phep ddi vdi tieu chuan chat lugng nude thiiy sinh va nudi thuy san IM.
5. Nhiet dp, dp muoi \h oxy hoa tan
Ket qua thdng ke cho thay, nhipt do nude bien dgng khdng Idn theo khdng gian va thdi gian, trir mgt sd tram cd dg sau Idn (CIO va T13) co sy chech Ipch dang ke nhipt do giira tang mat va tang day. Dieu nay chimg to kha nang trao d6i nude frong khu vyc Nha Trang - Nha Phu kha tdt.
Being 4. Mpt sd y l u td sinh thai trong nu'd'c
Y4ut6
V$tla ICrng (mg/l)
Nhi$t dO CC)
DO mu6i
(%o)
Oxy h6a tan
(mg/l)
BODs (mg/l)
Dia diim
Nha Phu Nha Trang
Nha Phu Nha Trang
Nha Phu Nha Trang
Nha Phu Nha Trang
Nha Phu Nha Trang
Gi^ trj Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Dao dOng Trung binh
Miia kho 0,48 - 14,10 (n = 24)
6,01 ±4,16 0,60 - 5,30 (n = 29)
1,80 ±1,07 23,40 - 29,90 (n = 24)
27,51 ±2,22 19,80 - 28,40 (n = 29)
24,96 ± 2,58 22,30 - 34,00 (n = 24)
31,71 ±3,14 23,10 - 34,20 (n = 29)
32,24 + 2,01 5,40 - 7,00 (n = 24)
6,29 ± 0,53 4,57 - 7,08 (n = 29)
6,22 ±0,62 0,70 - 2,10 (n = 24)
1,16±0,43 0,32 -1.12 (n = 29)
0,73x0,20
Mua mira 2,3 - 67,00 (n = 20)
19,49 ±17,14 2,10 - 25,30 (n = 25)
9,73 ±7,08 24,60 - 28,70 (n = 20)
26,57 ±1,38 24,30 - 27,80 (n = 25)
26,09 ±1,06 1,70 - 33,20 (n = 20)
24,69 ± 8,48 2,60 - 33,90 (n = 25)
26,16 ±9,69 5,00 - 7,10 (n = 20)
6,25 ± 0,62 3,01 - 7,38 (n = 25)
6,17 ±0,85 0,35 - 0,88 (n = 20)
0,63 ±0,18 0,22 - 0,76 (n = 25)
0,44 ±0,21
QCVN-2008 hi
50,0(*)
30,0r)
a 5,00
e.OD
Ghi chii: (*): QCVN-lO/2008/BTNMT: Quy chuan ky thudt qudc gia vi chdt luang nude biin ven bd (Tieu chudn diing cho nuoi trong thuy san vd bdo ton thuy sinh).
(**): QCVN-08/2008/BTNMT: Quy chudn ky thudt quoc gia ve chdt lupng nude mat (Tieu chudn diing cho bdo ton thuy sinh).
440 Tuyen t$p Hgi nghj KHOA HQC TOAN QUOC V £ SINH HQC B|£N V A PHAT TRI^N B£N Vt>NG
Dp mudi vyc nude Nha Trang - Nha Phu bien dgng kha Idn, nhat la frong thdi ky miia mua (bang 4). Do anh hudng eiia dong lye dja nen trong miia mua, khu vyc dinh dam Nha Phu va cac cira s6ng cd sy khac biet d6 mu6i kha Idn so vdi cira dam - noi tiep giap bien va cac vyc nude bien ngoai (bang 4). Tai viing nude bien ngoai (cac fram CIO, T13,..), dg mudi it thay doi frong ca 2 miia vi it chju anh hudng ciia dong lye dja.
N6ng do 6xy boa tan frong nude d vimg nghien ciru bien dgng khong nhieu, dat gia frj trung binh tuong d6i cao (bang 4). Ngoai trir tai cira song Be (fram 15) cd ndng dg oxy hoa tan thip, n6ng dp oxy boa tan fren tit ea eac tram con lai deu thoa man tieu chuan chat lugng nude cho nudi fr6ng thiiy san IM.
Ciing nhu oxy hoa tan, biln dgng BOD5 frong vimg nghien ciiu kh6ng Idn va gia frj trung binh kha thip (bang 4). Gia fri BODs ghi nhan dugc d vimg Nha Trang - Nha Phu vin thip hem gia fri BOD5 trung binh d vimg ran san hd (1,81 ± l,73mg/l), vimg rimg ngap man (1,59 ± l,46mg/l) va viing nude tr6i Nam Trung Bg (1,64 ± 0,70mg/l) 13, 6/ va gia frj BOD5 fren toan viing thoa man tieu chuan chat lugng nude ven bd cho nu6i tr6ng thuy san IM.
IV. KET LUAN
Cung nhu nhieu vyc nude ven bd nhiet ddi khac, nang suat sinh hgc so cap d vyc nude Nha Trang - Nha Phu bien dpng manh theo ca kh6ng gian va thdi gian va chju sy chi phoi cua dieu kien sinh thai dac thii. Ket qua nghien ciiu cho thay:
- Trong miia kho, nang suat th6 trung binh tai vyc nude Nha Phu cao hon vyc nude Nha Trang (vyc nude Nha Phu dao ddng: 30,00 - 354,00mgC/m^/ngdy, trung binh: 127,56 ± 91,39mgC/m^/ngay; vyc nude Nha Trang dao dgng: 27,00 - 346,40mgC/m^/ngdy, trung binh:
104,29 ± 11,10mgC/m^/ngdy) frong khi trong miia mua, nang suat tho fren 2 vimg deu cao hon trong miia kh6 nhung kh6ng co sy khac biet ro rang giira 2 vyc nude (Nha Phu dao ddng: 33,20 - 521,lOmgC/m^/ngay, trung binh: 148,08 ± U4,^lmgC/m^/ngdy; Nha Trang dao dpng: 28,50 - 503,%OmgC/tn^/ngay, trung binh: 152,33 + \5\,59mgC/m^/ngay). Nang suit th6 cao tap trung d khu vyc nu6i frong thiiy san phi'a Tay Nam dam Nha Phu, vimg ven bd cira Sdng Cai, sdng Cira Be va khu vyc Tay Nam Hon Tre (vdi nang suat th6 cd 200mgC/m^,ngdy).
- Cung nhu nang suat so cap, n6ng dp chl-a bien dpng manh theo kh6ng gian, thdi gian va lien he vdi nang suit thd bdi bieu thiic: Ndng suat tho (mgC/m^,ngdy) = 67,943*ln(chl-a) + 120,01 (R' = 0,4884)
- N6ng dp mu6i dinh dudng trong miia mua cao hon trong mua khd tren ea 2 vyc nude nghien ciru va kh6ng co gia fri vugt qua gidi ban Tieu chuin chit lugng nude thuy sinh va nuoi thuy san cua Viet Nam. Trong miia kh6, ca 2 vyc nude deu mang dac frung dinh dudng ciia moi trudng nude bien, trong khi trong miia mua, vyc nude Nha Phu chju chi phoi manh ciia nguon dinh dudng mang tinh lye dja, frong khi do vyc nude Nha Trang vIn mang dac trung dinh dudng ciia m6i trudng nude bien.
- Trir mgt vai gia fri ghi nhan dugc d dinh dam Nha Phu va cira Song Cai frong miia mua, mac dii co bien dgng Idn nhung n6ng do vat chit lo lirng tren toan vyc nude nghien ciiu van con th6a man tieu chuan chat lugng nude thiiy sinh va nudi thiiy san cua Vipt Nam.
- Do muoi vyc nude Nha Trang - Nha Phu bien dgng kha Idn, nhit la frong thdi ky miia mua, khu vyc dinh dam Nha Phu va cac cira song cd sy khac biet dg muoi kha Idn so vdi cira dam - noi tiep giap bien va cac vyc nude bien ngoai.
Tieu ban: CONG NGHE SINH HOC BlfeN VA M 6 I TRUONG ^ 4 4 1
- N6ng do 6xy hoa tan trong nude d vimg nghien ciru bien dong khong nhieu, dat gia tri trung binh tuong doi cao. Ngoai trir tai cira Song Be, ndng do oxy hoa tan fren tat ca cac tram con lai deu thoa man tieu chuan chat lugng nude bao ton thiiy sinh va nu6i thiiy san.
- Cac yeu t6 nhiet dp, oxy boa tan, nhu cau oxy sinh boa (BOD5) tren toan viing thay d6i frong pham vi nho va thoa man tieu chuan chat lugng nude bao t6n thuy sinh va nuoi thuy san.
V. LOfI CAM ON
Tac gia chan thanh cam on dong nghiep cac phong: Vat ly, Sinh thai va Moi trudng, Thuy - Dja - Hoa, Vien Hai duong hpc da tham gia khao sat va cung cap dir lieu thyc hien bai viet nay.
VI. TAI LIEU T H A M K H A O
1. Bp Tai nguyen va M6i trudng, 2009. Quy chuan Ky thuat quoc gia ve chat lugng moi trudng. Ha Ngi, 2009. 114fr.
2. Dai khi tugng thiiy van khu vyc Nam Trung bg, 2004. Dac diem khi hau va thuy van tinh Khanh Hoa. Nha Trang, 2004. 152fr.
3. Nguyen Tac An, 1996. Nang suat sinh hgc so cap va hieu img sinh thai cua dong nude tr6i d vimg bien Nam Trung Bg. Trong tap "Cac c6ng trinh nghien ciru viing nude tr6i manh Nam Trung Bg", frang 114 - 129. Nxb Khoa hgc va Ky thuat, 210 tr.
4. Nguyen Huu Huan, 1999. Estuarine systems of the South China Sea region: carbon, nifrogen and phosphorus fluxes (Nha Trang bay). LOICZ REPORTS & STUDIES NQ. 14. 1999.
LOICZ IPO, Texel, The Netherlands, pp.: 121 - 125.
5. Nguyen Hiru Huan va Phan Minh Thy, 1998. Nang suat sinh hgc so cap viing delta Me'kong va mgt s6 yeu t6 sinh thai cua nd. Tuyen tap Bao cao khoa hpc. Hpi nghj khoa hpc cdng nghe biln toan quoc lin thir IV. Ha Ngi, 12 - 13/11/1998. Nxb Thong ke. Ha Ngi, 1999. Tr
1147- 1154.
6. Nguyin Hiru Huan, H6 Hai Sam va Phan Minh Thy, 2000. Dgng hgc qua trinh sinh boa tieu thu oxy frong nude viing cira sdng Cai (Nha Trang). Tuyen tap Bao cao khoa hpc. Hpi nghj khoa hpc BIEN DONG - 2000. Nha Trang, 19 - 22/9/2000. Nxb Ndng nghiep. TP H6 Chi Minh, 2001. Tr. 2 8 7 - 2 9 4 .
7. Nguyin Hiru Huan, 2007. Nang suat sinh hge so cap va mpt s6 yeu t6 sinh thai lien quan d viing biln ven bd Binh Dinh. Tuyen tap Bao cao Hgi nghj Qu6c gia "Bien D6ng - 2007".
Nha Trang, 12 - 14/09/2007. Nha xuit ban Khoa hge ty nhien va Cong nghe. Ha Ngi, 2008.
Tr.:481 -494.
8. Paul g. Falkowski and Avril D. Woodhead, 1992. Primary Productivity and Biogeoehemical Cycles in the Sea. Plenum Press. New York and London, 550pp.
9. Soren Laurentius Nielsen, Gary T. Banta and Morten Foldager Pedersen, 2004. Estuarine nutrient cycling: the nutrient primary producers. Kluwer Academic Publishers, 2004, 303pp.
10. Timothy R. Parsons, Yoshiaki Maita and Carol M. Lalli, 1984. A Manual of Chemical and Biologycal Methods for Seawater Analysis. Pergamon Press, 173 pp.
4 4 2 Tuy^n tgp HQi nghj KHOA HQC T O A N Q U 6 C V £ SINH HQC BI^N VA P H A T TRlfeN B £ N VCfNS
THE PRIMARY PRODUCTIVITY OF PHYTOPLANKTON AND RELATED ECOLOGICAL PARAMETERS IN NTIA TRANG - NHA PHU WATERS
(KHANH HOA)
Nguyen Huu Huan, Nguyen Tac An and Bui Hong Long
SUMMARY ^ Based on data collected from the co-operated project of Vietnam - Norway (NUFU) taken
in Nha Trang - Nha Phu (Khanh Hoa) waters, during 2007 - 2009, the primary produerivity of phytoplankton and related ecological parameters in the waters have been described and discussed. The results have showed that, the primary productivity in Nha Trang - Nha Phu waters has sfrongly varied according to temporal and spatial. The primary productivity of the water in Nha Phu lagoon is higher than in the Nha Trang bay, the productivities of the waters in the rainy season are higher than in the dry season. Generally, the primary productivity of Nha Trang - Nha Phu waters is higher than one of the Tonkin gulf, the upwelling water in the South of Vietnam but lower than one of Binh Dinh coastal waters. Me'Kong delta waters. In dry season, both of the waters have nutrient characteristic of seawater environment but in rainy season, while Nha Phu water has nutrient characteristic of freshwater environment, Nha Trang water has still nutrient characteristic of seawater environment.
Despite some values of total suspended solid (TSS) in the top of Nha Phu lagoon and Cai estuary (Nha Trang) are out of the water quality standard for aquaculture, the ecological parameters of the waters (temperature, pH, total suspended solid, dissolved oxygen, BOD5) in the waters have varied in the criteria of Vietnamese aquaculture and coastal water quality.