Tieu ban Sinh thdi, Mdi tncdng vd qudn ly Bien D E X U A T PHU'CfNG P H A P Q U A N T R A C M O I TRU'OfNG T A I C A C M O D A U K H I V U N G B I E N N U ' d C S A U Of V I E T N A M Tran K h a n h Tung Vien Dau Viet Nam Trung tdm Ngbien ciiu va Phdt trien An toan va Mdi trudng Ddu kbi Email: tungtk.cpse@vpi.pvn.vn Ciing v&i khuynh hu&ng phat trien cdc dir dn ddu khixa bd, cong tdc quan trdc moi tru&ng bien viing nuac sdu xa bd lr& nen rdt cdn thiet Tren ca sd cgp nhgt cac quy trinh quan trdc moi tru&ng ngodi khoi hi?n co cUng nhu lua chgn phuang lien, thiit bi Idy mdu thick hgp; cong tdc khdo sdt idy mdu cho viing nuac sdu xa b& du^c ddnh gid Id khd thi tgi Vi^t Nam Vi^c gop phdn ddm bdo cong tdc an todn sue khoe moi tru&ng cho cdc hogt dgng diu ndi chung vd cUng gop phdn chien lug^c quoc gia ve cha quyen bien ddo Abstract A PROPOSED METHOD FOR ENVIRONMENTAL MONITORING AT OIL AND GAS EXPLOITATION PROJECTS IN DEEP- SEA WATERS OF VIETNAM As the petroleum operators tend to develop far offshore projects, il is necessary to perform environmental monitoring surveys for deep-sea area Based on the modification of current procedures for offshore monitoring and the selection of appropriate sampling devices and instruments, the task of sampling for deep-sea area is assessed to be feasible in Vietnam This ensures health-safety-environment performance for oil and gas operation and further contributes to national marine sovereignty strategy Di^T VAN DE Ddu la tai nguyen Idn nhdt d thim lyc dja nude ta va la nguon tai nguyen co tam chien lupc quan trpng Din Tap doan Ddu QuIc gia Viet Nam (PVN) dS xac dinh dirpc nhieu be tram tich nhu cac bl Cdu Long, Nam Con Son, Ma Lay -Thd Chu v.v , day deu la cac be duac danh gid CO triin vpng ddu Idn va khai thac thugn Ipi Tdng tru lupng dy bao dja chat cua toan them lyc dia Vi?t nam xap xi 10 t j tdn diu quy ddl, trir lupng khai thac -5 ty tdn, tr& lupng dir bao khoang 1.000 ^ m^ [2], ' ~^ " Nhirng tyu cua nganh cong nghiep dau yong nhung nam qua gop phan khdng nho cho phat triin kinh tl ddt nude, dam bao an ninh nSng lupng quIc gia Ngoai ra, n^anh dau cung gop phdn khing djnh chu quyen cua nude ta tren Biin Dong theo cong phap qudc te va md dirdng hyp tac, phyc vu muc tieu tri hoa binh, dn dinh va h&u nghj giira cac nude khu vyc Hien cac nude tren thi gidi da va dang phat trien tham dd va khai thac dau tai cac viing biin nude sau xa bd, nhilu dy an diu viing nude sau da dupe trien khai tir hang chyc nam tgi nhilu qudc gia tren the gidi nhu tgi viing vjnh Mexico, Brasil, viing Tay Chau Phi [1] Khuynh hudng cung nSm ke hoach phat UiSn ciia nganh dau Vi?t Nam nguon tai nguyen dau Jdii tgi phdn Idn cac mo quan trpng gin bd dang cang thu h?p, Uong nhirng phat hi^n Hgi nghi Khoa hgc vd Cdng nghe bien todn qudc Idn tlncV: diu mai lai tap trung d cac vimg nude sau, xa bb VI vay, viec tang cudng tham dd va khai thac dau a tai cac vimg biin xa bd la hit siic cap thilt va co mpt y nghTa quan trgng khong chi de Ai In djnh an ninh nang lupng, dam bao cac hoat dpng kinh te ma cd y nghTa circ ky quan trgng cong tac bao ve, giu vung chii quyen, an ninh quoc gia tren bien Tap doan Dau QuIc gia Viet Nam da de chiln lupc tang toe ciia iTnh vuc tham khai thac dau khi, co chuang trinh tim kiliii-lham dd dau vimg nude sau, xa bd Day la nh&ng vin dl mangy nghTa dpt pha hoat dgng ciia PVN, chiia dyng nhieUcahpi nhung cijng diy thach thiic doi vdi nhirng ngudi lam cong tac tham - khai thac dau Trong thai gian vira qua, cac dan vj ciia PVN da va dang tien hanh nhieii chuong trinh tham cac tilm nang dau xa bd Cac chuyen gia thugc Vien Ddu (PVN) da tinh dugc tiem nang diu va phan Vung triin vpng dau cho khu vyc be Phii Khanh la 509,52 trieu tan dau quy, doi, khu vyc Tu Chinh - Vung May 750, 57 trieu tan dau quy doi va them Iiic dja TSy Nam la 33,77 trieu tan dau quy doi [2] Xi nghiep Lien doanh Dau Vietsovpetro ciing da de chien lupc boat dgng cho giai doan 2011-2015, nhin manh vi^c day manh diu tu cac phuang tien, ky thuat hien dai, ap dgng cong nghe mdi, dam bao cho Vietsovpetro dii sue vuaii cac viing mdi, vCing nuac sau, xa bd., Ciing vdi su phat trien vugt bgc cong tactham do, khai thac, vgn chuyen, che bien va phan phoi cac san pham dau khi; cong tac an toan, sire khoe, moi trudng ludn dugc nganh dau khf xem la cong tac quan trpng nham dam bao an toan, sy on djnh ciia cac hoat ddng san xuat.kinh doanh dong thdi gop phan bao ve mdi trudng, quan tr§c moi trudng bien cho cdng tac tham va khai thac dau ngoai khoi la mgt nhiing hoat dpng quan trpng nhat Di cung voi khuynh hudng phat trien cac du an dau xa bd, nhu cau quan trac moi truong bien sau xa ba (va cac cong tac danh gia tac dgng moi trudng tuong ling) ciing vi the mEi tang cao M^c dfi cac nghien ciiu ve moi trudng bien nude sau da dupe khdi dgng a mpt s6 nude phat trien tii khoang 20 nam qua nhung van kha nhieu khia canh moi truang van chua duac biet den, d^c biet la cac anh huong ciia nhCi'ng ngu6n thai tir cac hoat dpng ciia nguoi den moi trudng song cgng dong sinh vat day bien tai day CONG TAC QUAN TllAC VUNG NU'dC SAU 2.1 Quan trac moi trudng bi£n tai cdc cong trinh ddu ngoai khoi hien Trong thdi gian qua, viec quan trac moi trudng bien xung quanh cac cdng trinh dau klii ngoai khoi da va dang dirpc nganh dau thyc hien djnh ky nhim phat hien va danh gia anh hudng ciia cac hoat dgng tham do, khai thac, van chuyen v.v doi vdi moi trudng bien xung quanh Cong tac; da gop phan khong nho vao tich chung ciia cac chuang trinh bao ve moi trudng ciia nganh cung nhu giiip ho trp lap cac kl hogch moi trudng tuong lai Trung tam Nghien ciiu va Phat trien An toan va Moi trudng Diu khi-Vien Diu Viet Nam (CPSE) CO ban 15 nam kinh nghiem va da thyc hien rdt nhieu dgt khao sat moi trudng co sd cho cac giai doan tham do, phat trien mo cung nhu khao sat moi trudng djnh ky sau khoan cho cac cong trinh dau tai them luc dja Viet Nam Kit qua khao sat da tao dilu ki?n cho cac cdp quan 1;^ ciia PVN ghi nhan dugc hien trgng chung ciia moi trudng bien tai cdc khu vyc co hogt dgng ddu khi, dong thai cung giiip cho cac to chiic dau cd kl hoach vd chuong trinh hanh dpng phii hop nhim giam thieu anh hudng ciia cac hogt dgng san xuat kinh doanh din mdi tnrdng Tiiu ban Sinh ihdi, Mdi trudng vd qudn ly Bien 503 Nham quy dinh phuang phdp thong nhat cho cdng tac khdo sat liy mlu, phdn tich mlu va soan thao bao cao mdi tnrdng, PVN da ban hanh "Hudng ddn quan trac mdi tncdng Biu vuc lan cgn cdc cong trinh ddu tren bd tgi Viet Nam" [11], Hudng din dp dimg cho viec quan trdc mdi tnrdng xung quanh cac cdng trinh ddu ngoai khoi dl xdc dinh mdi trudng tnidc va sau cd hoat ddng ddu Hudng din quy diidi nguyen tic thuc hien, mang ludi khdo sdt, tin suit khdo sat, ddi tupng khao sdt, phuang phap liy mlu/phan tich n^u ciing nhu phuong phdp xd: 1;^ s6 USu, danh gia sd lieu va scan thdo bao cao hien trgng mdi trudng Ddy la ca sd quan trpng de CPSE thuc hien cdng viec nhdm ddm bdo tmh thing nhdt ciia cac chuang trinh khao sat, tir dd phdt hi^n cdc anh hudng cua hogt ddng dau den mdi trudng (nlu cd) Ddi tupng nghien ciiu cdng tac khdo sat mdi trudng ngodi khai la cac thdng sd d^c trung cho su phdn bo kich thudc hat cua trim tich ddy bien, cac thdng sl lien quan den vdt chit d nhilm tram tich (hydrocacbon, cac khn loai nang) va cdc thdng s6 ciia quan xa sinh vgt day Ngoai ra, chdt luong nude mat cung dupe giam sat thdng qua cac thdng sd nhu pH, ham lupng oxy hda tan (DO), ham lupng ddu, ham lupng cac kim loai nang v.v Hien nay, diilt bi chinh cho viec liy mdu trim tich ddy ngoai khai la gau Day Day la thiet bi chuyen dung dupe v|in hanh bing h6 tdi va cdu tren cac tau dich vu diu vdi dien tich be mat lay n^u Id 0,1 m^ (hinhl) Hinh Cong tdc lay mdu tram tich biin sir difng gdu Day Tuy nhi8n, phuong phdp khdo sat Idy mlu nhu da de cap tren day chu yeu dupe th^c hi?n d cac md diu t?i cdc vdng hiln gin bd nhu hien nay, noi chilu sau day bien thudng nho ban 150m Ddi vdi cdc vdng biin sdu hon, phuang phap neu tren dupe ddnh gia la gap nhilu kho khan s\r khdc biet cdc ylu t l dnh hudng den cdng tdc keo/thd gau nhu l\rc dong chay, chiSu sau day biSn, yeu ciu v l lupng mau cin thu dupe dgc thu phan bo cua cpng ding sinh vat day tgi vung nude Hdi nghj Khoa hgc vd Cdng nghe bien todn quic Idn thu V 2.2 Quan trie moi trirdng tai cac vung bien nude sau xa bd * Bgc diim moi trudng vung biin nude sau xa bd Viing biin nude sau cd mdi trudng sinh hpc dpng, noi co mpt so it loai sinh vgt song dilu kien dac biet nhu ap suit cdt nude cao, ham lupng oxy hoa tan thap, moi trudng nude Ignh va hiu nhu thilu anh sang Trong cac nghien ciiu gin day nhdt vl mdi trudng bien sau va cac ylu to sinh hpc ling dyng cdng tac quan ly cac hoat dpng tham dd khai thac dau khi, ranh gidi tren diing dl phan biet vung nude sdu so vdi vimg nude ndng duoc xac dinh la 200m [6] Ap suit Khi dp sau day biin tang them 10 m, ap suit cpt nude tang them atmosphere Ap suit tang anh hudng din cac phan ling hda hpc xay cdt nude vd tren bl mat day bien' Nhi?t dp Mdi trudng nude sau dupe dac trung bdi nhiet dp thip vdi khoang biin thien tir khoang 10°C tai sdu 200 m din khoang 2°C tai sau han 3000 m [6] Biin thien nhiet dp moi trudng nude tac dpng den sy phan bo ciia quan xa sinh vat Oxy hoa tan CJ mgt sl dp sau nhit djnh, ham lupng oxy hda tan nude dgt gia trj thip nhit Nguong sau tliay ddi giiia cac dai duong Tgi Vjnh Mehico, oxy hoa tan co gia trj thap nhit tai dp sau tir 200 m din 750 m [5, 6] Moi trudng sinh hoc Mdi trudng sinh hgc viing biin nude sau rit khac biet so vdi vimg nude ndng Hau het cac vung biin nude sau co tram tich mem va phin idn cac dpng vat day deu cd khd nang thich nghi mdi trudng tai Quan xa dpng vgt day ca Idn (macrofauna) vung nude sau co tinh phiic tgp [6, 7] Trong tdn tgi mdt so loai hilm gap vdi chi mpt vai ca the mau tram tich thu dupe ung vdi mdi loai * Phuang phdp luan quan trac viing nude sau Ve nguyen tic, co the irng dyng chuong trinh quan trie hi?n dp dyng tgi viing bien nude nong gan bd cho cdng tdc liy mlu vung nude sau xa bd Tuy nhien, viec liy mlu viing nude sau can giai quyet nhiing he qua khac biet dp sau gay nen Cac vin dl dupe torn tit nhu sau: ^ Danh gia sy phii hgp ciia mgng ludi lay mlu: chilu sau cot nude Idn hon, phan bd chat thai khoan va cac chat thai cd lien quan se rpng han nen mgng ludi cac trgm lay mau se phai bao triim pham vi Idn ban Mgng ludi liy mlu thich hpp se duac xac djnh dya tren ket qua ap dyng cac md hinh md phong viec lan truyin chdt thai khoan nham udc lupng pham vi nhiem be mat day biin ^ Tren ca sd xac djnh pham vi phan bo miin khoan thai xung quanh cdng trinh diu khi, tien hanh danh gia lai mang ludi liy mlu hi?n dang ap.dyng va co sir dieu chinh neU can thilt •^ Lya chpn phuong tien va thilt bi Idy mlu thich hop cho viing bien nude sau Tiiu ban Sinh thdi, Mdi tncdng vd qudn ly Biin Mpt sd thdng so iay mlu cin luu ^ liy mlu trim tich day viing nuac sdu dupe tom tit nhu sau: ^ Dien tich be mat Idy mdu/kich thicdcphgm vi khu vice Idy mdu Di?n tich bl m^t liy mau trim tich da;^ can dii Idn dl dam bao yeu ciu djnh tinh va dinh lupng cua phep phan tich (dgc bi8t la ddi vdi mau dpng v§t day vdn tuong ddi hiem viing nude sau) Tuang ty, kich thudc pham vi liy mlu cung cin dii Idn de ed thi bao triim khu vyc cd kha nang bj anh hudng bdi hogt dpng diu -^ So mdu Icip tgi cimg vi tri Idy mdu Sd mau Igp tram tich day can dii Idn de cd thi danh gia su phan bo ciia cac loai dgng vat day hilm d viing nude sau * Thiet bi vd ky thugt lay mdu vimg nirdc sdu Doi vdi cac khu vyc co ddy bien sdu hem 200m, khong the dung gau Day dB liy mlu nhu a viing nude ndng (phdn 2.1) vi dudi tac dpng ciia lyc ddng chay mgnh d vimg xa bd, ^au bi Idi cuin -va se cham day bien d vj tri kha xa so vdi vj tri thilt ke ban dau, dieu sg hgn che rdt nhilu kha ning thdnh cdng ciia viec thu mau Hien nay, tren thi gidi cdng tac liy mlu vung nude sau dupe thuc hien chu ylu dya tren hai phuang phap chinh nhu sau: Thu mdu bang cac dyng cy lay mau ket ndi vdi tau khdo sat bang cap chuyen dyng Sii dyng cac thilt bj quan trie ty ddng khdng ket ndi true tiep vdi tau khaO sdt Phuang phap thu mlu bing cac dyng cy kit ndi vdi tau khao sat dupe su dyng tir kha sdm cdng tac khao sat mdi trudng bien va van dupe dung rpng rai cho den hien Phuong phap nky it tdn kem, co thi bao quat pham vi khao sat rdng Idn Nhirng diem hgn che cua phuang phap niy la can nhiSu thdi gian de huy dgng phuang tien, thiet bj vd dyng cu den khu vuc lay mau d viing nude sau ciing nhu de hoan tat ca chuyen khao sat Phuong phap sir dyng cac thiet bi quan trie tu dpng khdng kit nii tryc tiep vdi tdu khao sat cd mgt sd uu diem nhu sau: Mpt sd thilt bj hogt dgng ngam dudi nude cd thS van chuyen cac chuyen gia xuong den dp sau cin khao sdt va vi the cho phep quan sat true tilp mdi trudng day va mdi trudng song cua quan xa sinh vat Trong nhiing nam gin day, cac thilt bj tren da dupe cai tien va phat triin manh me va cho ph^p tien hanh cac chuyin khao sat va lay mau dai han Tuy nhien, phuang phap co dilm hgn che la chi phi trang bj va van hanh kha cao so vdi cac phuong phap truyen thdng neu tren 2.3 Thiet bi, dung cu liy mau vung nude sau Mpt so phuang tien, thilt bj va dyng cy diln hinh cua hai phuang phap neu trfin dupe trinh bay dudi day: Phuang phdp thu mdu bdng cdc diJing c(i lay mdu kit noi vdi tdu khdo sdt Hi?n nay, hai dung cy liy mdu trim tich day phd bien vd co di?n tich be mat lay mau Idn la gau chuyen dyng c& Idn (di?n tich bl mat 0,1 m^) va box corer cd Idn (di?n tich bl m$t 0,25 m^) [8] Hgi nghi Khoa hgc vd Cdng ngh$ bien todn quic lan thit V Ddi vdi nmu thu dupe tii box corer, dien tich bl mat va dung lupng khd Idn nen lupng mlu thu dupe cd thi dap ling nhilu phep phan tich nhu phdn tich hda hpc (kich thudc hgt, ham luong v|t chit d nhilm v.v ) va phan tich smh hpc (quin xa ddng vdt day cd Idn) v.v Gdu chuyen dung Hinh cho thdy mpt nhiing dang don gian nhdt ciia gau liy mlu viing nude sau Dung cy cd thi dupe vgn hanh bing thuy l\rc hoac bang phuang phdp thd cdng Uu diem cua kieu gdu thii cdng la van hanh don gian, khdng phy thuOc dd sdu liy mlu ma chi phy thupc vao chieu ddi cap keo va Idid nang cda he tdi va khung ciu Dung cu cd thi lam viec d dp sau len din 4000 m S^:1 Gau chuyen dvmg Box corer Hinh Mgt so dung ci^ lay mau tram tich vung bien nude sau Box corer Hien box corer da trd dung cu lay mau chuan cho cac chuyen khao sat vimg nude sdu CO trim tich mim Dien tich be mat lay mau kha Idn (0,25 m^) cho phep thu mdt lupng Idn mau thdi gian khdo sat bj hgn che Be day lap mat trim tich day thu dupe cd thi dupe dieu chinh vd dgt gid tri cao nhat la 50 cm Tuong tu nhu kieu gau da neu tren, box corer cung dupe vdn hanh bang he tdi cau vdi chilu dai cap thich hpp Su difng cdc thiet bi quan trac khong ket noi tr^c dip vdi tdu khao sat Ddy la cac thiSt bj quan trac hogt dpng tu dgng ngam idudi nude dupe tich hpp cac dau dd cam ling de thu thap sd li?u mdi trudng Nguyen tic cac logi thilt bi diln hinh cho phuong phdp ndy dupe torn tit nhu sau; • Loai hoat ddng tu ddng ngam dudi nude bdng chuang trinh Igp sin de thu thap sd lieu mdi trudng Tieu bieu cho loai la cac thilt bi Autonomous Underwater Vehicles [12] Loai hogt dpng tu dpng ngam dudi nude bing chuong trinh lap sin nhung cd the ket ndi dii li?u vdi trung tam dilu khiln d phia tren Chfic nang ndy cho phep cac nha nghi6n ciiu cd the cgp nhat vd dieu chinh cac thdng sd chuang trinh khdo sat Tieu ban Sinh thdi, Mdi trudng vd qudn Iy BiJn 507 Nhin chung, cac thiet bi neu tr6n cd tmh co ddng cao, cho phep nit ngln thdi gian khao sat, tang chat lupng dii li?u thu thap dupe, mgt sd logi cd thi chuyen cha ngudi xuong den dg sau khao sat de quan trie tryc tilp bl mgt day biin Tuy nhien, diem hgn chi cda chung la gia cao, chi phi dao tao huan luy$n sd dyng dit va yeu ciu cao ve kj* thugt vgn hanh Ngoai ra, cac thilt bj chu ylu dupe dimg dl khao sat zhc hogt d^ng sdng ciia quin xa sinh vat day biin cung nhu cac thdng s6 mdi trudng ddy cd lien quan (bing each chup anh hoac diing cac ddu dd cam ling v.v ) KHA NANG U^fGDVNG 3.1 Danh gid kha nang irng dung Nhu da dl cgp a phan tren, cdng tac quan trie mdi trudng bien tgi Viet Nam hi?n hiu hit dupe CPSE thyc hi§n cho cac Id dau gin bd cd dp sau day hiln khdng Idn Vl vgy, phat trien chuang trinh khao sat cho viing nude sau xa bo, doi hdi phai giai quylt mpt so van de vl ky thu^t nhu cgp nh^t mang ludi quan trie, trang bj phuang tien va thiet bi liy mlu phu hpp, dieu chinh phuong phap xii ly mlu Tuy nhien, edng tac quan trie Idy mlu viing hiln nude sau xa bd dugc danh gia la hoan toan cd the thuc hien tgi Vi^Nam vdi nhiing ly sau: - C6 thi ling dyng va phdt trien hudng dan liy mau mdi trudng ngodi khai PVN ban hdnh, day la ca sd 1^ thuyet hiiu ich cho viec xay dyng chuang trinh quan trie xa bd Ngoai ra, dpi ngu chuyen vien ciia CPSE cung da cd nhilu nam kinh nghi?m vi$c ling dyng md hinh lan truyen miin khoan de udc lupng pham vi mdi trudng bj anh hudng bdi chat thai khoan - Dpi ngii chuyen vien va ky thuat vien ciia CPSE cd nhilu kinh nghifm cdng tac khao sat lay mau ngoai khoi, bao gdm tat ca cac cdng doan nhu thiet lap chuang trinh quan trac, chuan bj phuang tifn, dung cy, hda chat, khdo sat lay mau ngoai khai, bao quan mau, ghi chep sd li^u hi^n trudng, phan tich mlu, ling dyng cdng cy thong ke xir 1^ sl li^u phdn tich va sogn thao bao cao mdi trudng 3.2 Giai phap chung - Tren co sd hudng ddn quan trie mdi trudng ngoai khai hien nay, c^p nhgt vd md rpng phgm vi de CO thi ap dyng cho mdi trudng bien nude sau Vi?c bao gom xay dyng mgng ludi liy mau, nghien cii:u bo sung thdng sd phdn tich phii hop vdi vimg nude sau, dl phuong phap xir iy mau sinh hpc tai hien trudng v.v - Lya chpn phuong tien, thilt bi va dyng cy liy mlu thich hpp tiiy vao cac yeu to nhu dp sau viing biin khao sdt, kinh phi dy an v.v KET LUAN Ciing vdi khuynh hudng phat triin cac dy an diu xa bd, vi?c quan trac mdi trudng biin tgi cac khu vyc din trd nen cap thiet TrSn co sd cac quy trinh quan trie mdi trudng ngoai khoi hi?n cd; can thiet c$p nhgt, bd sung cac npi dung cy thi nliu thiet l|ip mgng ludi liy mlu, thdng so phan tich, phuang phap xu: ly mlu v.v Ngoai ra, can cu theo cac phan tich ve phuang ti?n vd thiet bj liy mlu nSu tren, cdng tac khao sat lay mlu cho viing nude sau xa bd dugc danh gid Id khd thi tgi Vi?t Nam Vi?c gdp phin dam bdo cdng tac an toan siic khde mdi trudng cho cac hoat dpng dau ndi chung vd ciing gdp phin chiln lupc quoc gia vl chii quyen blln dao Hgi nghi Khoa hgc vd Cdng ngh? biin loan quic Idn HA TAI LIEU THAM KHAO Baud, R.D., R.H Peterson, G.E Richardson, L.S French, J Regg, T Montgomery, T,S Williams, C Doyle, and M Doraer 2002 Deepwater Gulf of Mexico 2002: Amerii^^ Expanding Frontier OCS Study MMS 2002-021 U.S Department of the hiterior, Mineral! Management Service, Gulf of Mexico OCS Region, New Orleans, Louisiana 133 pp Bg Tai nguyen va Mdi trudng, 2007 Xac djnh tilm nang diu d vimg biin sau, xabi http://www.monre.gov.vn/v35/default.aspx?tabid=428&cateID=53&id=32611&codg=rni DW32611 Carey, D.A., D.C Rhoads, and B Hecker 2003 Use of laser line scan for assessmento response of benthic habitats and demersal fish to seafloor disturbance Jourml~D Experimental Marine Biology and Ecology 2&5-286:435-452 Carey, J.M and M.J Keough 2002 Compositing and subsampling to reduce costs m improve power in benthic monitoringprograms.£',s/u