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ABSTRACT. A fo ur-m a n party representing th e Arct ic In st itu te o f North America and th e D epa rtm e n t of Geo logy, Danmouth Coll ege, went to th e "Va rd Hunt I ce S h e lf in 1960 to obtain ice cores for subsequen t labor atory anal ys is. Th e overa ll obj ec ti ve of th e proj ec t was to st ud y th e st ruc tural and stratigraphi c hi story o f the shelf and its re latio nshi p to the e nvironm ent throug h labo ra tory a na lysis of t h e cores, using stratig ra phi c, petrologic, c h em ica l, and p hysica l me thods.Th e four co res nbtain ed were logged , packed, a nd shipped to Dartmouth Co ll ege for d c tailed st ud y. Th e st ra tigraphy a nd stru ct urc of th e ice we re studied und er natura l ancl plane pola ri zed light conditi oJlS. The res ults of th is initi a l wo rk showed that the cores were co mposed o f fo ur ice types : g lacier ice, lak e ice, ·sea ice, and transition ice. Chlorinity, su lfate, a nd density p ro fil es complemented m egasco pi c studi es a nd were most useful crite ria fo r pl otting stra ti g raphi c cha nges in ice type.R es u lts of th e in vestigations thus fa r h ave yield ed new info rm a ti o n a bout the g ross structure and stratigrap h y o f the ice sh e lf an d re-cntra nt. T h ey have also show n that the ph ysical and chemica l techniqu es e mployed will be useful in futur e ice-core a na lys is. R ESUME. U ne equipe de 4 hom mes apparten a nt a 1' ''Arcti c Institute of North Ameri ca" e t au " D epa rtment of Geology, D a rlm o uth Coll ege", a travaille sur le Ward J-Iunt I ce S helf e n 1960, pour obte nir d es carottes d estin ees a d es analyses en labo ratoire. L'obj ec tif g loba l d e ce proj e t eta it d 'et udie r l'h isto ire s tructura le et stratig rap hiqu e du shelf e t sa re la ti on avec l'en vironn e ment, a l'aide d 'anal yses en laboratoire d es carot tes utilisant d es method es stra tig raphiques, petrog raphiqu es, chimiques et physiques .L es 4 ca rottes o bte nu es o nt ete reperees, empaq uetees et cx pedi ecs pa r batea u, au " Dartmout h Coll ege" , pour d es etudes detaillees. L a stra tigra phi e e t la structure de la g lace ont e te etudiees dans des co nditions d e lumi ere naturell e e t po la risee dans un p la n. Les resu ltats d e ce p remi er travail m o ntrent q ue les ca ro tt es :sont com posees d e 4 t ypes d e g lace :-g lace de glacier-g lace de lac-glace de m er-g lace d e t ransiti o n. D es profils de densite e t de teneur en c hlo re e t sui fa te, ont comple te les etud es m egascopiques e t se sont reveles d es cri teres tres util es pour tracer les c ha ngemen ts stra tig raphiqu es d e typ es de g lace.Actu ellemenr, les res ul tats d e ces rech e rches on t fOLII'ni d e nouve ll cs info rmati o ns sur la stru cture g lobale e t la st ratigra phie d e l' ice-shelf. lis ont a ussi montre que les techniqu es physiques e t chimiques utilisees sero nt utiles dans les a n a lyses futures d es caro ttes d e g lace.ZUSAMMENFASSUNG. E in e Gruppe vo n 4 Mitarbeitern des A rc ti c In stitute o f North Am...

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The Fucus populations on rocky shores along 300 km of the coastal waters of southeast Sweden in the Baltic proper have been studied since 1984 at a number of fixed sites as part of monitoring programmes. This paper describes changes in distribution and abundance of F. vesiculosus and F. serratus during the period 1984-2001. Sheltered sites showed a consistent temporal and spatial pattern of Fucus spp. distribution over a coastline of 300 kilometres. The depth penetration and abundance of Fucus spp. increased during the 1980s. Around 1990 the development reversed as a consequence of grazing and in 1997 many sites were almost devoid of Fucus spp. Since 1998 both abundance and depth penetration have increased again, possibly as a result of local measures against eutrophication. Exposed sites, on the other hand, lost their Fucus populations at the beginning of the 1990s, and they have not recovered. Extended field studies lead us to deduce that the fixed sites referred to above were representative of the Fucus populations in the area investigated. Major declines, both at sheltered and exposed sites, are attributed to grazing by the isopod Idotea baltica. The populations of I. baltica may have been favoured by the continuing eutrophication of the Baltic, a series of mild winters in the 1990s, and a contemporary decline in some potential predators.

The Fucus populations on rocky shores along 300 km of the coastal waters of southeast Sweden in the Baltic proper have been studied since 1984 at a number of fixed sites as part of monitoring programmes. This paper describes changes in distribution and abundance of F. vesiculosus and F. serratus during the period 1984-2001. Sheltered sites showed a consistent temporal and spatial pattern of Fucus spp. distribution over a coastline of 300 kilometres. The depth penetration and abundance of Fucus spp. increased during the 1980s. Around 1990 the development reversed as a consequence of grazing and in 1997 many sites were almost devoid of Fucus spp. Since 1998 both abundance and depth penetration have increased again, possibly as a result of local measures against eutrophication. Exposed sites, on the other hand, lost their Fucus populations at the beginning of the 1990s, and they have not recovered. Extended field studies lead us to deduce that the fixed sites referred to above were representative of the Fucus populations in the area investigated. Major declines, both at sheltered and exposed sites, are attributed to grazing by the isopod Idotea baltica. The populations of I. baltica may have been favoured by the continuing eutrophication of the Baltic, a series of mild winters in the 1990s, and a contemporary decline in some potential predators.

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