dino£agellate cyst assemblages from e⁄ngham inlet

Dino£agellate cyst assemblages from E⁄ngham Inlet,Vancouver Island, British Columbia, Canada

Arun Kumar �, R. Timothy PattersonOttawa-Carleton Geoscience Centre and Department of Earth Sciences, College of Natural Sciences, Carleton University,

1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6

Received 14 March 2001; accepted 11 October 2001

Abstract

A palynological study of surface samples from Effingham Inlet, southwestern Vancouver Island, BritishColumbia, was carried out to assess environmental and oceanographic controls on the distribution of dinoflagellatecyst species. Generally dinoflagellate cyst assemblages from all samples are dominated by Operculodiniumcentrocarpum sensu Wall and Dale, 1966, Spiniferites spp. and round brown (protoperidinioid) cysts. The differencesamong the assemblages are mainly in relative and absolute abundance of various taxa, presence and absence ofvarious protoperidinioid taxa, species diversity (Shannon Diversity Index), dinoflagellate cyst concentration in thesamples, and ratio of terrestrial to marine palynomorphs. Dinoflagellate cyst assemblages in the two sub-basins of thisinlet are quite distinct, with the inner basin characterized by lower diversity and the outer basin being characterized byhigher diversity due to the occurrence of several protoperidiniacean species. Primary productivity in this inlet isenhanced by periodic incursion of nutrient-rich surface water from the Pacific Ocean which is related to coastalupwelling. Primary productivity is higher in the outer basin than the inner basin. 7 2002 Elsevier Science B.V. Allrights reserved.

Keywords: fjord; palynomorphs; dino£agellate cysts; salinity; oceanography

1. Introduction

The object of this study was to explore the re-lationship between dino£agellate cyst assemblagesfound in the modern sediments of E⁄ngham In-let, Vancouver Island, British Columbia, and var-ious environmental and oceanographic factorsthat might control their distribution.

Like diatoms, dino£agellates are important pri-mary producers. Their relative abundance variesaccording to season, geographical location andwater depth, with greatest concentrations at shal-lower depths between 18 and 90 m (Taylor, 1987).Regions of highest dino£agellate productivity areoften areas of upwelling, which provide increasednutrients. Dino£agellate ‘blooms’ also cause ‘redtides’, which may be highly toxic and are oftenresponsible for high ¢sh mortality, thus directlya¡ecting the ¢shing industry (Tappan, 1980; Tay-lor, 1987; Okaichi et al., 1989). Fossil dino£agel-late cyst assemblages have been related to the

0031-0182 / 02 / $ ^ see front matter 7 2002 Elsevier Science B.V. All rights reserved.PII: S 0 0 3 1 - 0 1 8 2 ( 0 1 ) 0 0 4 2 8 - X

* Corresponding author. Fax: +1-613-520-2569.E-mail addresses: [email protected] (A. Kumar),

[email protected] (R.T. Patterson).

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movement of oceanic currents, upwelling, climatechange, winter and summer sea-surface tempera-ture and depth and paleoceanography (Head andWrenn, 1992; Powell et al., 1990; Aksu et al.,1989).

Fjords such as E⁄ngham Inlet are essentiallylarge sediment traps with relatively high sedimen-tation rates. There is also little exchange betweenbottom waters in E⁄ngham Inlet and the openocean because of the presence of two sills (Figs.1 and 3). For this reason conditions within thesub-basins of E⁄ngham Inlet generally varyfrom suboxic to anoxic, resulting in depositionof annual varved layers that can provide a veryhigh-resolution record of paleoenvironmentalevents.

Since £ushing of inlets like E⁄ngham Inlet isrelatively infrequent, the dino£agellate cysts fall-ing through the water column are of primarilylocal origin rather than transported from theopen ocean (Dale, 1976). This characteristic is ad-vantageous, as the sedimentary record preservedin these inlets document signi¢cant local oceano-graphic events with the proxy signal not being lostthrough bioturbation as often occurs in the openocean.

The baseline proxy data presented here willeventually be used to interpret late Holocenechanges in climatic and oceanographic conditionsbased on dino£agellate cyst £oras preserved incores collected from the inlet. This research ispart of a large multidisciplinary research projectwhose aim is to relate variations in climatic, en-vironmental and oceanographic conditions in Ef-¢ngham Inlet to changes in ¢sh populationsthrough the Holocene. This information is of stra-tegic economic importance, as it will help ¢sheriesmanagers to better allocate resources in the re-gion. The study of dino£agellate cysts from boththe recent and fossil sediments from E⁄nghamInlet promises to enhance our ability to derive ahigh-resolution paleoclimatic and paleoceano-graphic history of the region.

2. Geology

E⁄ngham Inlet is 15 km long, located on the

southwest coast of Vancouver Island. It is con-nected to the Paci¢c Ocean through a wide baycalled Barkley Sound (Fig. 1). This inlet has twosub-basins, the inner and outer, divided by a 45-m-deep sill (inner sill) located in a narrow channel.Another 65-m-deep sill (outer sill) separates theouter basin from Barkley Sound (Fig. 3). Themaximum recorded depth in the inner basin is120 m and 210 m in the outer basin. Tidal marshesare present on both sides of the outer basin andtwo other large marshes are present near the headof the inlet. E⁄ngham River £ows into the headof this inlet, and a small creek also £ows into theouter basin. The high level of annual rainfall re-ceived in this area results in numerous additionalsmaller streams £owing into the inlet. The entireregion is mountainous and covered with conifer-ous forests although the western part of the outerbasin has recently been logged.

The inlet is surrounded by Mesozoic volcanicrocks, which form a steep and rocky coastline.The underwater slopes of the inlet are steep, andcoring in shallower depths was unsuccessful, yield-ing little sediment. This suggests that margins ofthe inlet are either made of Mesozoic volcanicrocks or Quaternary glacial gravel.

The sampled sediment consisted of soft, soupybrown mud with organic matter (essentially plantfragments) ranging from 10% in shallow areas to90% in the deeper parts of the basins (Patterson etal., 2000). A distinct layer of coarse, black andloose organic matter a few centimeters thick, con-sisting primarily of decomposed vegetation, waspresent at the sediment surface in the outer basin.At shallower depths (6 72 m) in the outer basinand at the mouth of the inlet, the sediment was a¢rm gray marine mud with a lower organic con-tent. Based on preliminary analysis of laminaerecorded in freeze cores collected in October,1999, the rate of sedimentation varies between0.5 and 1 cm/yr (Patterson et al., 2000).

3. Oceanography and climate

The climate of western Vancouver Island is cooltemperate and wet. Wind patterns along the Pa-ci¢c coast are controlled by two atmospheric

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cells : the Aleutian Low (AL) and the North Pa-ci¢c High (NPH; Fig. 4; Kendrew and Kerr,1955; Thomson, 1981; Patterson et al., 1995). Inthe northeast Paci¢c, there is a seasonal oscilla-tion between the two systems. During the summerwhen the land is hot and the ocean cool, the re-

gion comes under the in£uence of the NPH (Fig.5). NPH winds generate a southward coastal driftand an o¡shore Ekman transport that triggerscoastal upwelling. During the winter the NPH ispushed southward and the area comes under thein£uence of the AL, centered in the western Gulf

Fig. 1. Geographic location of E⁄ngham Inlet, Vancouver Island, showing sample sites and depth contours (m).

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A. Kumar, R.T. Patterson / Palaeogeography, Palaeoclimatology, Palaeoecology 180 (2002) 187^206 189

of Alaska (Fig. 4), that generates a northwardcoastal drift and a consequent onshore Ekmantransport that prevents upwelling.

The dominant surface currents seaward of theVancouver Island continental margin are thesouthward-£owing California Current and north-ward-£owing Alaska Current (Thomson, 1981;Patterson et al., 1995). In winter, the CaliforniaUndercurrent is con¢ned to the persistent upwell-ing regions of California (Thomson, 1981; Patter-son et al., 1995). In summer, the relatively warm,high-salinity water of the California Undercurrent£ows northward along the continental margin atdepths between 250 and 300 m. The upwelling of

this deeper (s 150 m) slope water is of particularinterest to this study. It is most prevalent fromMay through August when it leads to a dramaticincrease in productivity. This upwelling is slow,only 1^10 m per day, but it has a profound e¡ectover thousands of square kilometers of the westcoast of North America (Thomson, 1981; Patter-son et al., 1995). This nutrient-rich water spreadsinto adjoining coastal inlets such as E⁄nghamInlet, where it contributes to increased productiv-ity (Patterson et al., 2000). Intermittent high-sa-linity incursions take place in the winter, underthe in£uence of strong northerly winds, or duringthe early summer upwelling season as a result of a

Fig. 2. Oxygen and salinity pro¢les for selected stations at the head of E⁄ngham Inlet, the inner basin, the outer basin, and out-side the outer sill.

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combination of weak tidal currents, signi¢cantrainfall and strong (s 10 m/s) northwesterlywinds (Thomson, 1981; Gri⁄n and LeBlond,1989).

During a reconnaissance cruise of the CanadianCoast Guard Ship (CCGS) John P. Tully in De-cember 1995, temperature, salinity, oxygen andtransmissivity pro¢les were measured at 11 sta-tions throughout E⁄ngham Inlet. In March1997, data from an additional 20 stations werealso taken (Fig. 2). Vertical salinity pro¢les indi-cate well-developed estuarine-type strati¢cation(Fig. 3). Salinity increases from the surface watertoward deeper waters with the top 20^30 m of thewater column being less saline, especially in theinner basin and parts of the inlet closer to theriver mouth and swamps. The salinity-inducedstrati¢cation in combination with the in£ux ofhigh levels of land-derived organic matter andthe input of local marine productivity results inthe formation of suboxic to anoxic bottom con-ditions in these basins (Fig. 3; Patterson et al.,2000).

Water is well-oxygenated to around 50 m depthin the inner basin, oxygen content decreases rap-idly, and at 60 and 70 m depth, oxygen values ofzero or near zero are reached, and H2S appears.In the outer basin, the water properties of theanoxic/dysoxic/suboxic layers are highly uniform,indicative of di¡usive processes in stagnant, qui-escent water (Patterson et al., 2000).

4. Previous work

Few Holocene dino£agellate cyst studies havebeen made in the fjords of Vancouver Islandand on the British Columbia shelf. Palynologicalstudies of two short cores from Saanich Inlet insoutheastern Vancouver Island were published byHeusser (1983), who plotted the relative abun-dance of dino£agellate cysts in the overall paly-nomorph assemblages spanning over the last 12kyr without identifying any dino£agellate cysttaxa. Mudie (1998a,b) presented an ultra-high-res-olution record of seasonal and decadal climatechange indications of paleo El Nin‹os and red tidesbased on dino£agellate cyst studies from ODPSite 1034B drilled in Saanich Inlet. Most recentlyKumar and Patterson (2000) presented a recon-naissance study on the distribution of dino£agel-late cysts in the bottom sediments of E⁄nghamInlet.

5. Materials and methods

Samples were collected during a cruise ofCCGS John P. Tully in March, 1997, from theuppermost 10 cm of gravity-cored sediments.Since the rate of sedimentation in this inlet isvery high (0.5^1.0 cm/yr; Patterson et al., 2000)the top 10 cm of sediments were considered indi-cative of present conditions. Sampling depth was

Fig. 3. Water depth, salinity and temperature strati¢cation in the E⁄ngham Inlet showing dissolved oxygen pro¢les at four di¡er-ent locations.

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determined by shipboard sonar, and the positionof sample stations by using a shipboard GlobalPositioning System (Fig. 1). Most sediments weremuddy, unconsolidated and contained signi¢cant

terrestrially derived organic matter. The sampleswere placed in plastic bags and kept in cold stor-age aboard the ship, and once back on shoremethanol was added as a preservative. Sampleswere then sieved to remove coarse material andto separate the ¢ne sediment. The ¢ne sediment(6 63 Wm) was chemically macerated for prepara-tion of palynological slides at GEOTOP, Univer-site¤ du Que¤bec a' Montre¤al following the methodof de Vernal et al. (1999).

Species identi¢cation was primarily based onRochon et al. (1999). Each slide was thoroughlyscanned for rare species before counting, and 10

Fig. 4. (A) Atmospheric and oceanographic features of up-welling o¡ the British Columbia coast during the summer:northerly NPH winds generate at the surface, the southwardShelf-Break Current and a consequent o¡shore Ekman trans-port-inducing upwelling thus bringing high-salinity deepwater closer to the surface. (B) Atmospheric and oceano-graphic features of downwelling o¡ the coast of VancouverIsland during winter: southerly AL winds generate a north-ward drift (NE Paci¢c Coastal Current) and a consequentonshore Ekman transport. This causes accumulation of low-density less saline water on the surface, thus restricting theupwelling of deep water (modi¢ed after Thomson, 1981).

Fig. 5. Air pressure at sea-level in January and July for thenortheast Paci¢c region from 1951 to 1970. During winter,when the land is cold and the ocean relatively warm, a large-scale counter-clockwise low-pressure gyre (AL) develops,dominating the weather over the entire northeastern Paci¢c.During summer, when land is hot and the ocean relativelycool, a large-scale clockwise high-pressure cell (NPH) movesup from the south and dissipates the AL. Arrows indicateprevailing wind direction. Value on diagram +10 000 dividedby 10 gives the pressure in millibars (modi¢ed after Favoriteet al., 1976).

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complete transacts were counted at U400 magni-¢cation until at least 500 specimens of palyno-morphs (both marine and terrestrial) werecounted. Counts obtained from richer sampleswere often higher than 500 (Table 1). The ratioof terrestrial to marine palynomorphs, the ratio ofgonyaulacoid to peridinioid (G:P ratio) dino£a-gellate cysts, the percentage of various dino£a-gellate cyst species, and the Shannon DiversityIndex (SDI) for each sample were also calculated(Table 2) using the method described by Sagemanand Bina (1997). In addition, the concentrations(specimens/cc) of total palynomorphs, total dino-£agellate cysts and various dino£agellate cyst taxawere also calculated (Table 3) using the method ofSmith (1998). Distribution patterns are shown forvarious parameters such as the number of cystsand cyst concentration (Fig. 6a), G:P ratio andSDI (Fig. 6b) and concentration (specimens/cc) ofvarious dino£agellate cyst taxa (Fig. 6c,d).

6. Results

The palynomorph assemblages identi¢ed in Ef-¢ngham Inlet contain rich and diverse autochtho-nous (dino£agellate cysts, foraminiferal remains,copepod eggs and invertebrate remains) and al-lochthonous (pollen, spores, fungal remains andthecamoebians) £ora and fauna (Table 1).Although not directly a part of this study, andthus not included in the counts, several types offungal spores, hyphae and fruiting bodies alsooccur commonly in our samples. All the dino£a-gellate cysts identi¢ed in this study are listed (Ap-pendix 1).

Total palynomorph concentrations vary fromas high as 210 473 grains/cc in sample EI 02(depth 31 m), located close to the marsh at thehead of the inlet, to as low as 31 814 grains/cc insample EI 32 (depth 210 m), located in the outerbasin (Table 3). Assemblages are dominated byterrestrial palynomorphs in most samples, espe-cially Tsuga spp., bisaccate pollen (Pinaceae)and inaperturate pollen (Cuppressaceae). Inaper-turate palynomorphs occur in overwhelminglylarge numbers but show a tendency to be brokenor damaged, and otherwise poorly preserved.

These specimens were not included in the countsas damage was often so severe that it was di⁄cultto determine whether specimens were inaperturatepollen or leiosphaerid acritarchs. Several types ofangiosperm pollen also occur in these samples,most commonly Alnus and Betula. Fern spores(mainly monolete) occur in signi¢cant numbersin almost all samples.

The proportion of marine palynomorphs in oursamples varies considerably, ranging from a lowof 3.5% of the total assemblage in sample EI 03,located near the head of the inlet, to a high of70.48% of the total assemblage in sample EI 28,located between the outer basin and BarkleySound (Table 2). Samples from the outer basinand near the mouth of the inlet have a higherproportion (39.1^70.48%) of marine palyno-morphs than from the inner basin and nearhead of the inlet (3.5^34.3%). The ratio of terres-trial/marine palynomorphs is high in the innerbasin (ranging between 26.1:1 in sample EI 03and 1.8:1 in sample EI 13) and in samples fromshallow waters close to the shore and near marshyareas. The ratio signi¢cantly decreases (1:1) in theouter basin and toward Barkley Sound (Table 2).

Among the protists, foraminiferal test liningswere found in almost all samples, and their num-ber increased signi¢cantly in the outer basinwhere oxygen levels are higher (Fig. 3). Despitestrong acid treatment during preparation, threegenera of thecamoebians were also noted in sam-ples from the inner basin and from shallow loca-tions close to marshy areas (Table 1). Patterson etal. (2000) reported the occurrence of 31 arcella-cean (thecamoebians) species from the same sam-ples studied in this paper.

The numbers of dino£agellate cysts counted ineach sample and the cyst concentration (speci-mens/cc) varies considerably from one sample toother. However, these numbers are signi¢cantlyhigher in the outer basin and Barkley Soundthan for the inner basin (Table 2; Fig. 6a). Bothsets of data show a broadly similar pattern. Deep-er water (s 60 m) locations were found to havehigher cyst concentrations than shallow locations,mainly due to sediment focusing at the bottombecause sediments deposited along the marginsof the basin tended to slip down and re-deposit

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Table 1Raw counts showing distribution of palynomorph taxa in surface sediment samples, E⁄ngham Inlet

Notes: (1) Foraminiferal linings and thecamoebians are not included among palynomorphs; (2) one Lycopodium clavatum tablet (10 679 spores/tablet) was added toeach sample; (3) inaperturate palynomorphs and fungal remains were not counted.

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Tab

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(Continued

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Table 3Concentration (specimens/cc) of selected dino£agellate cyst taxa in E⁄ngham Inlet

Note: Protoperidinium americanum cysts and Quinquecuspis concreta are included among the protoperidinioids.

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at the bottom of the basin, enhancing the concen-tration of palynomorphs.

A low-diversity gonyaulacoid £ora dominatesthe dino£agellate cyst assemblages, and is repre-sented primarily by Operculodinium centrocarpumsensu Wall and Dale, 1966 (including the varietywith short processes), Spiniferites ramosus and afew specimens of Spiniferites elongatus. O. centro-carpum sensu Wall and Dale is the most abundantdino£agellate cyst forming 38.41^88.88% of thedino£agellate cyst assemblage (Table 2). The con-centration of this species ranges from a low of1383 specimens/cc in sample EI 03, near head ofthe inlet, to a high of 106 790 specimens/cc insample EI 28, located between the outer basinand Barkley Sound (Table 3; Fig. 6c). Percentagesof Operculodinium spp. signi¢cantly decrease inthe outer basin and in Barkley Sound (Table 2).

Spiniferites spp. occur in almost all the samples,but form only 0.74^22.53% of the dino£agellatecyst assemblage (Table 2). The concentration ofSpiniferites spp. ranges from a low of 282 speci-mens/cc in sample EI 05, near head of the inletand close to a marsh, to a high of 5161 specimens/cc in sample EI 41, closest to Barkley Sound (Ta-ble 3; Fig. 6c). The percentage of Spiniferites spp.signi¢cantly increases in the outer basin and inBarkley Sound (Table 2).

Although peridinioid cysts are a minor constit-uent of the assemblage, they are represented byseveral species belonging to the genera Brigante-dinium, Lejeunecysta, Votadinium and Selenopem-phix, as well as indeterminate round brown pro-toperidinioid cysts (Tables 2 and 3).

Round brown cysts (RBC) are the second mostdominant group of dino£agellates next only toOperculodinium spp. These cysts occur in all sam-ples, except sample EI 05 (Tables 2 and 3). Thehighest concentration of these cysts was found insamples from the outer basin and deepest loca-tions of the inner basin (Fig. 6d). Islandinium min-utum occurs in low numbers in almost all samples(Tables 2 and 3). The highest concentration ofthis species was observed in the samples from out-er basin, but one sample, EI 11, from the innerbasin also had a very high concentration of I.minutum (Fig. 6d).

Cysts of Pentapharsodinium dalei, Polykrikos

kofoidii and Polykrikos schwartzii occur in lownumbers in deeper water locations of the innerbasin and in all locations of the outer basin andBarkley Sound (Tables 2 and 3).

The ratio of G:P cysts in the E⁄ngham Inlet isquite variable, although values are signi¢cantlyhigher for the inner basin than the outer basin(Fig. 6b). Lower G:P ratios in the outer basinindicate higher primary productivity than for theinner basin.

SDI values vary considerably from sample tosample, and range between 0.309 in sample EI05, located close to marsh near the head of theinlet, to 1.839 in sample EI 35, located in theouter basin (Table 2). SDI values are signi¢cantlyhigher for the outer basin, Barkley Sound, thanthe inner basin (Fig. 6b). This is mainly due togreater in£uence of high salinity, oxygenated oce-anic waters from Barkley Sound in the outer ba-sin than inner basin.

Dino£agellate cyst assemblages in the outer ba-sin are thus mixed assemblage of dino£agellatesfrom the inlet as well as from the open ocean. Theconcentration of Operculodinium spp. (up to100 000 specimens/cc) and Spiniferites spp. (upto 4000 specimens/cc) is highest among samplesfrom the outer basin. At locations close to Bark-ley Sound (EI 37 and EI 41) Operculodinium spp.concentrations decrease from an average of 20 000specimens/cc to almost 10 000 specimens/cc,whereas Spiniferites spp. concentration increasefrom an average of 1000 specimens/cc to a highof over 5000 specimens/cc (Fig. 6c). This relation-ship is also re£ected in the relative and absoluteabundance of these species (Tables 2 and 3).Thus, judging from the modern salinity gradientsin our study area, the abundance of Spiniferitesspp. is a better indicator of more oceanic condi-tions than Operculodinium spp.

The concentrations of RBC and Islandiniumminutum, as observed for most other species,varies considerably from sample to sample, butbroadly follow similar trends, with both taxa hav-ing highest concentrations in samples from theouter basin (Fig. 6d). The average concentrationof RBC was around 3000 specimens/cc, but thisvalue reached a high of over 14 000 specimens/cc(sample EI 28) in the outer basin. A higher con-

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Fig. 6. (a) Distribution of cysts counted and cyst concentration. (b) Distribution of G:P ratio and SDI. (c) Distribution of Oper-culodinium spp. and Spiniferites spp. (specimens/cc). (d) Distribution of RBC and Islandinium minutum (specimens/cc).

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centration of I. minutum was found in deeper lo-cations throughout the inlet (Fig. 6d).

7. Discussion

Dino£agellate cyst assemblages from E⁄nghamInlet are dominated by Operculodinium centrocar-pum sensu Wall and Dale, Spiniferites spp. andround brown protoperidinioid cysts, with di¡er-ences between samples mainly relating to varyingproportions of these taxa. However, signi¢cantdi¡erences between samples also relate to thepresence and absence of various peridiniaceantaxa, SDI, dino£agellate cyst concentrations(specimens/cc) in the samples and the ratio of ter-restrial to marine palynomorphs. These di¡eren-ces are closely correlated with salinity variationsdue to the proximity to marshes, streams, shore-line and open ocean.

Due to variations in temperature, salinity, oxy-gen level and the in£uence of the Paci¢c Ocean inthe surface waters of E⁄ngham Inlet, basins andchannels are distinct sub-environments within thisInlet. Since these sub-environments have distinctdino£agellate cyst assemblages, they are discussedseparately.

7.1. Inner basin

Nine samples (samples 2 through 12, location 4had no sample) are from the channel connectingthe inner basin with the head of the inlet, andonly two samples, 13 and 14, are from the innerbasin itself (Fig. 1). The salinity of surface watersin this basin is low, and varies from 25x nearthe head of the inlet to 27x within the innerbasin (Fig. 2). This variation is due to in£ux offresh water from E⁄ngham river. The salinity in-creases to 32.5x at the bottom, resulting in thewater column being strati¢ed, and dissolved oxy-gen levels being depleted at the bottom (Fig. 3).

Operculodinium spp., RBC and Spiniferites spp.are the main dino£agellate cysts in the inner ba-sin, with rare specimens of a few other peridinia-cean species (Table 2). Their absolute abundanceis low, but relative abundance is high because offewer dino£agellate cyst species occuring in the

inner basin than the outer basin. For example,the absolute abundance of Operculodinium centro-carpum sensu Wall and Dale, ranges from 15 (EI03) to 240 (EI 09), but relative abundance rangesbetween 42.38% (EI 14) and 88.88% (EI 09). Thisobservation is also re£ected by the low SDI(0.309^1.862) of the samples from the inner basin.Terrestrial/marine palynomorph ratios are higher,since most samples were close to marshes andriver mouth. The inner basin dino£agellate cystassemblages typically represent a local dino£agel-late £ora with a minimal in£uence from the openocean.

The lower salinity, lesser in£uence of Paci¢cOcean water, and the relatively closer proximityto a river mouth, marshes and shore line are ma-jor controls on the distribution of dino£agellatecysts in the inner basin and channel connectingthis basin to the mouth of E⁄ngham River. Thesetaxa are almost ubiquitous and tolerate a widerange of salinities (20^36x) and water temper-atures (freezing winters to 22‡C in summer), andoccur both in the neretic and oceanic domains(Rochon et al., 1999). The rarity of protoperidi-nioids is another distinguishing character of thisassemblage. Salinity has been found to control thediversity of dino£agellate cysts in the waters o¡Germany, where similar low-diversity dino£agel-late cyst assemblages were reported from the low-er-salinity waters of the Keil Bight and higherdiversity in the higher-salinity marine waters ofthe German Bight (Nehring, 1997).

Higher G:P ratios, lower diversity (SDI) andlower proportions of round brown protoperidi-nioid cysts indicate lower primary productivityin the inner basin than the outer basin.

7.2. Outer basin

Twelve sample locations were sited in this basinand another ¢ve stations were located in the chan-nel connecting this basin with Barkley Sound(Fig. 1). Due to the periodic in£ux of oceanicwaters in this basin, dissolved oxygen levels inthe top 80 m of water in this basin are higherthan the inner basin. This basin is characterizedby higher species diversity (SDI 1.256^1.915) aswell as higher relative and absolute abundance

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of species. The higher species diversity in this ba-sin is due to the occurrence of several peridinia-cean species which were not found in the innerbasin. Spiniferites spp. occur in signi¢cantly high-er proportions in the outer basin samples and arevery high in samples close to Barkley Sound. Theouter basin dino£agellate cyst assemblages aremixed and are assumed to represent both localinlet dino£agellates and those from the openocean.

More signi¢cant in the assemblage is the pres-ence of Brigantedinium spp., an opportunistic tax-on that has a widespread distribution under vary-ing temperature and salinity conditions. It hasoften been associated with upwelling zones, andthus nutrient enrichment. Although heterotrophic,Brigantedinium spp. depend on primary produc-tion as a food source (Rochon et al., 1999).

Among the important species found in this as-semblage Spiniferites elongatus is typically a cooltemperate species that has been widely reportedfrom the fjords of Norway (Dale, 1996). Islandi-nium minutum occurs as a minor constituent(6 2% of the assemblage) but is important as ithas been associated with cold to sub-Arctic watermasses, and is known to occur in fjords to shelfenvironments and tolerates a wide range of salin-ities (about 5^10x to 35x, Head et al., 2002).Brigantedinium simplex is known from estuarineto inner neritic cool temperate regions (Edwardsand Andrle, 1992). Votadinium calvum and V. spi-nosum, as reported, here were grouped togetherwith other taxa as miscellaneous congruentidia-cean cysts by Rochon et al. (1999), and their dis-tribution was associated with warm winter andsummer conditions (about 16‡C and 21‡C respec-tively) and salinities of 6 36x. Cysts of Penta-pharsodinium dalei occur in a wide range of envi-ronmental conditions with respect to temperatureand salinity and were also reported from Norwe-gian fjords (Dale, 1976, 1977; Rochon et al.,1999).

Along the southeast continental margins ofCanada, high percentages of Protoperidiniumspp. have been recorded in areas characterizedby high nutrient inputs, low-salinity surfacewaters and high primary productivity, includingthat of diatoms, thus showing a⁄nities with estu-

arine-type environments (de Vernal et al., 1997).Mudie (1998a) reported the common occurrenceof Protoperidinium leonis ( =Quinquecuspis concre-ta) in Saanich Inlet, a silled fjord in southeasternVancouver Island.

Dino£agellate cyst assemblages from the E⁄ng-ham Inlet are characterized by the presence offairly high proportions of round brown protoper-idinioid cysts in almost all samples (Fig. 6d; Ta-ble 2). Dale (1996) found the presence of highproportions of protoperidiniods as the dominantsignal for upwelling in southwestern Africa andvarious other upwelling regions of the world in-cluding southern California. Due to coastal up-welling, nutrient-rich surface water of the Paci¢cOcean spreads into adjoining coastal fjords, suchas E⁄ngham Inlet (see 3. Oceanography and cli-mate), where it stimulates increased productivity.Although there are no published records of anycyst signal for these coastal upwellings o¡ Van-couver Island, it is quite possible that protoperi-diniods such as RBC in E⁄ngham Inlet are dueto incursions of nutrient-rich surface water fromthe Paci¢c Ocean.

Dino£agellate cyst assemblages from the outerbasin are characterized by higher cyst concentra-tions, lower G:P ratios and higher diversity (SDI)than the inner basin. All these factors indicatethat primary productivity is higher in the outerbasin than the inner basin. This is also indicatedby presence of several protoperidinioid taxa in theouter basin, whose presence in the inner basin isonly rare.

Cysts of gymnodinioid Polykrikos schwartziiand P. kofoidii occur sporadically and in lownumbers. They have been previously reportedfrom the temperate regions of the North Atlanticwhere they are associated with summer temper-atures of 12‡C and salinities of about 35x (Ro-chon et al., 1999).

8. Comparison with other dino£agellate cyst £oras

Mudie and Harland (1996) have synthesized allavailable published and unpublished informationon the distribution of dino£agellate cysts in thePaci¢c Ocean, and de¢ned ¢ve £oras that corre-

PALAEO 2787 21-5-02


spond to di¡erent sectors of the cool, temperateCalifornia Undercurrent. The dino£agellate cystassemblage ‘WI’ is distributed in the o¡shore re-gions of Washington^Oregon just south of theVancouver Island. This is the region where theKuroshio-North Paci¢c Current System dividesto form the sub-Arctic northward-£owing Alas-kan Current and the cool temperate southward-£owing California Undercurrent. Protoperidiniumspp., Spiniferites spp. and Operculodinium centro-carpum morphotypes dominate the assemblage,with Brigantedinium spp. co-dominant in thenortherly San Juan area. This assemblage isclosely comparable to the outer basin assemblagesof E⁄ngham Inlet.

Since E⁄ngham Inlet is a fjord, it is importantto compare the dino£agellate cyst £oras from oth-er fjords. Norwegian fjords have long beenstudied by Dale and co-workers. Dale (1976)found that cysts behave as ¢ne silt particles inthe sedimentary regime, increasing in abundanceas the percentage abundance of ¢ner sediment in-creases, usually with increased water depths. Thiscondition was also observed in E⁄ngham Inlet,where deeper locations had numerically abundantand more diverse dino£agellate cyst £ora.

Dale (1976) recorded a higher diversity of go-nyaulacoid cysts in Trondheimsfjord, than we ob-serve in E⁄ngham Inlet. The gonyaulacoid cystgenera Bitectatodinium, Impagidinium, Nemato-sphaeropsis (Gonyaulax spinifera group) and Lin-gulodinium (G. polyedra) occur in Trondheims-fjord, but not in E⁄ngham Inlet. E⁄nghamInlet assemblages, however, have more diverseand abundant protoperidinioid cysts than Trond-heimsfjord. These di¡erences are possibly relatedto a greater in£uence of oceanic waters in Trond-heimsfjord and higher primary productivity in Ef-¢ngham Inlet.

Ecophenotypic adaptation to sub-normal salin-ities in some cyst species results in morphologicalchange (Wall et al., 1973), including reduced pro-cess length (Dale, 1996). Operculodinium centro-carpum sensu Wall and Dale with short processesoccur consistently in E⁄ngham Inlet assemblages(Tables 1 and 2), although salinities of the surfacewaters in E⁄ngham Inlet are relatively higher(22^27x) than those observed by Dale (1996)

for this morphotype from the low-salinity (10^20x) waters of Oslofjord and the Baltic Sea.

In order to observe the latitudinal distributionof dino£agellates, Dale (1996) plotted 17 dino£a-gellate taxa (both living motile forms and deadcysts) from the Norwegian fjords ranging fromsouth Oslofjord (just under 60‡N) to north Va-rangerfjord (about 70‡N). Among them, Opercu-lodinium centrocarpum sensu Wall and Dale, Spi-niferites ramosus (as S. bulloideus), S. elongatus,Brigantedinium simplex (as Protoperidinium coni-coides) and P. americanum occur in all the fjordsexcept in the northernmost Varangerfjord, andalso occur in E⁄ngham Inlet. Selenopemphixquanta (as Protoperidinium conicum) occurs in allthe Norwegian fjords as well as E⁄ngham Inlet.There is a possibility that there are even moretaxa common to these regions, if we considerthat several forms of Spiniferites in E⁄ngham In-let were grouped as S. ramosus and Spiniferitesspp. However, two common dino£agellate cysts,Bitectatodinium tepikiense and Lingulodinium ma-chaerophorum, occur in the Norwegian fjords butare absent from E⁄ngham Inlet.

Most of the dino£agellate cyst taxa found inE⁄ngham Inlet also occur in fjords, bays andother restricted bodies of marine waters in cooltemperate regions of the Paci¢c Ocean and north-ern Europe (Rochon et al., 1999).

9. Conclusions

(1) Well-preserved and diverse assemblage ofpalynomorphs were recovered from the surfacesediments of E⁄ngham Inlet.

(2) The palynomorph assemblages are dominat-ed by allochthonous terrestrial palynomorphs,with autochthonous marine palynomorphs consti-tuting a minor proportion.

(3) Dino£agellate cyst assemblages are more di-verse in the outer basin (a mixed fjord and ocean-ic assemblage) than the inner basin (fjord assem-blage).

(4) Gonyaulacoid dino£agellate cysts occur inall samples and are represented in higher propor-tions than peridinioid dino£agellate cysts.

(5) Operculodinium centrocarpum sensu Wall

PALAEO 2787 21-5-02


and Dale (including short processed variety) is themost common species, and occurs in all samples.Other common gonyaulacoid dino£agellate cystsare Spiniferites ramosus and S. elongatus.

(6) Protoperidinioid dino£agellate cysts are mi-nor constituents of the assemblage but includemany more species than the gonyaulacoid cysts.Most peridinioid species belong to the genera Is-landinium, Brigantedinium, Lejeunecysta, Quinque-cuspis, Selenopemphix and Votadinium. AlthoughIslandinium occurs in most samples, other generaare more prominent in the outer basin.

(7) Peridinioid dino£agellate cysts occursmainly in the outer basin and deeper locations.

(8) Round brown (protoperidinioid) cysts occurin all samples, but are more common in the deep-er samples, probably due to sediment focusing.

(9) Shallower (6 60 m) and low surface-watersalinity locations (close to rivers, creeks andmarshes) are dominated by terrestrial palyno-morphs, and deeper (s 60 m) and higher-salinitylocations are dominated by marine palyno-morphs.

(10) Remains also of foraminifera occur in al-most all the samples, but are common in deepersamples and all the samples in the outer basin andchannel connecting Barkley Sound.

(11) The distribution of dino£agellate cysts inE⁄ngham Inlet is primarily controlled by the sa-linity variation of surface waters due to proximityto rivers, creeks, swamps and to the open ocean.

(12) The dino£agellate cyst assemblages re-corded from E⁄ngham Inlet conform with theknown distribution of dino£agellate cysts in thecool temperate regions of the northern hemi-sphere, and they also occur in estuarine environ-

ments and low surface salinity environments offjords.

(13) Primary productivity in E⁄ngham Inlethas been enhanced by the periodic incursions ofcoastal upwelling-related nutrient-rich surfacewater from the Paci¢c Ocean. Primary productiv-ity is higher in the outer basin than the innerbasin.

Acknowledgements

We thank editors of this special publication,M.J. Head and A.B. Beaudoin, for encouraging usto contribute this paper. We are grateful to R.Harland, M.J. Head and an anonymous reviewerfor critical reviews of the paper. We thank A. deVernal for facilitating sample processing at GEO-TOP, University of Quebec in Montreal. We alsothank R.E. Thomson of (Institute of OceanSciences, Sidney, BC) for field support, and L.Taylor (Carleton University) and Anita Kumar(University of Toronto) for drafting figures andother computer-related help. This research wassupported by a NSERC strategic grant to R.T.P.

Appendix 1

The following dino£agellate cysts, here listedwith their thecate counterparts, were identi¢edin E⁄ngham Inlet surface sediments. The nomen-clature and cyst-thecal equivalences are from Fen-some et al. (1993), Head (1996) and Head et al.(2002).

Paleontological (cyst) name Theca-based NameGonyaulacoid dino£agellatesOperculodinium centrocarpum (De£andre and Cookson 1955) Wall,1967 sensu Wall and Dale, 1966

Protoceratium reticulatum (Clapare¤de and Lachmann, 1859)Bu«tschli, 1885

Spiniferites elongatus Reid, 1974 Gonyaulax spinifera complexSpiniferites ramosus (Ehrenberg, 1838) Mantell, 1854 Gonyaulax scrippsiae Kofoid, 1911Peridinoid dino£agellatesIslandinium minutum (Harland and Reid in Harland et al., 1980)Head et al., 2002

Protoperidinium? sp. indet

Brigantedinium cariacoense (Wall, 1967) Lentin and Williams, 1993 P. avellanum (Meunier, 1919) Balech, 1974B. simplex Wall, 1965 ex Lentin and Williams, 1993 Protoperidinium sp. indetLejeunecysta oliva (Reid, 1977) Turon and Londeix, 1988 Protoperidinium sp. indet.

PALAEO 2787 21-5-02


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dino£agellate cyst assemblages from e⁄ngham inlet

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