Archived Content

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.

Bibliography of the Maurice Lamontagne Institute

Jean-Claude THERRIAULT

ROY, S., F. BLOUIN, A. JACQUES, J.-C. THERRIAULT, 2008. Absorption properties of phytoplankton in the Lower Estuary and Gulf of St. Lawrence (Canada). Can. J. Fish. Aquat. Sci., 65: 1721-1737 .

Models of ocean colour rely on information about phytoplankton absorption, which varies according to community composition and photoacclimation. Here we show that pigment packaging, which is strongly determined by the size structure of local algal populations, represents a dominant factor in the Estuary and Gulf of St. Lawrence, accounting for ˜50 %-80 % of the reduction in phytoplankton absorption at 440 nm during the spring bloom periods and for 24 %-48 % before and after the blooms. This is consistent with the importance of diatoms in this environment. Comparison between three methods of estimating packaging gave average values within less than 20 % of each other during the blooms. Changes in pigment composition, which also affect phytoplankton absorption, were more important outside bloom periods (particularly in the Gulf), although this influence was relatively modest (11 %-13 %). This was accompanied by an increase in photoprotective pigments and an absorption peak in the ultraviolet range (˜330 nm). Regional variations in phytoplankton absorption reflected bloom conditions, whereas detrital particulate material was highest in the upstream Saguenay region (often more than 60 % of the absorption of total particulate material at 440 nm (ap(440))) and was at least 20 %-30 % elsewhere. This information is a first step towards the development of regional models of ocean colour.©2008 NRC Canada

MAS, S., S. ROY, F. BLOUIN, B. MOSTAJIR, J.-C. THERRIAULT, C. NOZAIS, S. DEMERS, 2008. Diel variations in optical properties of Imantonia rotunda (Haptophyceae) and Thalassiosira pseudonana (Bacillariophyceae) exposed to different irradiance levels. J. Phycol., 44(3): 551-563 .

Diel variations of cellular optical properties were examined for cultures of the haptophyte Imantonia rotunda N. Reynolds and the diatom Thalassiosira pseudonana (Hust.) Hasle et Heimdal grown under a 14:10 light:dark (L:D) cycle and transferred from 100 μmol photons · m-2 · s-1 to higher irradiances of 250 and 500 μmol photons · m-2 · s-1. Cell volume and abundance, phytoplankton absorption coefficients, flow-cytometric light scattering and chl fluorescence, and pigment composition were measured every 2 h over a 24 h period. Results showed that cell division was more synchronous for I. rotunda than for T. pseudonana. Several variables exhibited diel variability with an amplitude >100 %, notably mean cell volume for the haptophyte and photoprotective carotenoids for both species, while optical properties such as flow-cytometric scattering and chl a-specific phytoplankton absorption generally showed <50 % diel variability. Increased irradiance induced changes in pigments (both species) and mean cell volume (for the diatom) and amplified diel variability for most variables. This increase in amplitude is larger for pigments (factor of 2 or more, notably for cellular photoprotective carotenoid content in I. rotunda and for photosynthetic pigments in T. pseudonana) than for optical properties (a factor of 1.5 for chl a-specific absorption, at 440 nm, in I. rotunda and a factor of 2 for the absorption cross-section and the chl a-specific scattering in T. pseudonana). Consequently, diel changes in optical properties and pigmentation associated with the L:D cycle and amplified by concurrent changes in irradiance likely contribute significantly to the variability in optical properties observed in biooptical field studies.©2008 Phycological Society of America

HARVEY, M., M. STARR, J.-C. THERRIAULT, F. SAUCIER, M. GOSSELIN, 2006. MERICA-nord program: monitoring and research in the Hudson Bay complex. AZMP Bull. PMZA, 5: 27-32 .

Click to see all the text

[Abstract only available in French]
Le complexe de la baie d’Hudson (comprenant la baie d’Hudson, le détroit d’Hudson ainsi que le bassin de Foxe) représente probablement le plus grand estuaire nordique du monde. Cet estuaire est une composante importante du courant du Labrador qui exerce une influence prédominante sur le climat de la partie est de l’Amérique du Nord. La dynamique de circulation des masses d’eau dans cette région nordique est fortement influencée par les écoulements d’eau douce provenant notamment des bassins de drainage de la baie d’Hudson et de l’arctique. Cette région abrite près de la moitié des populations Inuits du Nunavut et du Nunavik, et est caractérisée par une forte biodiversité reflétant l’influence significative des eaux arctiques et subarctiques de l’Atlantique Nord. Cet écosystème nordique a été identifié comme un « point chaud » pour la conservation de la biodiversité marine, mais aussi comme l’une des régions les plus sensibles aux changements et à la variabilité climatique. Afin de pouvoir détecter, comprendre, suivre et prédire les changements environnementaux dans cette région nordique, les scientifiques du MPO, région du Québec, ont initié en 2003 un programme de monitorage appelé MERICA-nord (pour études des MERs Intérieures du CAnada). Ce programme de monitorage complémente celui effectué dans la mer intérieure du golfe du Saint-Laurent (MERICA-sud). Dans sa conception, sa réalisation et son échantillonnage de base, ce programme de monitorage s’inspire du Programme de Monitorage de la Zone Atlantique. Il accommode en plus plusieurs programmes de recherche associés qui sont effectués par des partenaires tant à l’interne qu’à l’externe du MPO, comme par exemple le secteur universitaire. MERICA-nord est supporté par le Centre national d’excellence pour la recherche aquatique dans l’Arctique (N-CAARE en anglais). Un élément clé du programme est l’intégration des besoins des scientifiques avec l’expertise et la capacité de support logistique de la Garde côtière canadienne; ce programme a en effet profité jusqu’à maintenant de temps de navire offert par la Garde côtière canadienne sur une base d’opportunité. MERICA-nord permet finalement au MPO d’assumer ses obligations nationales et internationales de base en ce qui concerne l’étude des milieux marins nordiques, afin de répondre aux enjeux sociaux et globaux émergents que soulèvent l’impact de l’activité humaine (ex., les développements hydroélectriques) ou encore des changements climatiques. Dans ce contexte, l’environnement du complexe de la baie d’Hudson est encore bien peu connu.

PEPIN, P., B. PETRIE, J.-C. THERRIAULT, S. NARAYANAN, G. HARRISON, J. CHASSÉ, E. COLBOURNE, D. GILBERT, D. GREGORY, M. HARVEY, G. MAILLET, M. MITCHEL, M. STARR, 2005. The Atlantic Zone Monitoring Program (AZMP) : review of 1998-2003. Can. Tech. Rep. Hydrogr. Ocean Sci., 242, 87 p .

We outline the results of the self-assessment by the Atlantic Zone Monitoring Program (AZMP) based on the milestrones set out in the original proposal and on a series of key issues identified during the Fifth Annual General Meeting of the Atlantic Zone Monitoring Program and supported by the Atlantic Science Directors. The report is divided into 12 sections which aim at providing an overview of the program's accomplishments, progress to date as well as identifying key concerns about maintaining current program activities and future developments. The report is capped with four sections that outline some of the benefits in the understanding and predictability of marine systems that have been derived from continued long-term monitoring activities.

PLOURDE, J., J.-C. THERRIAULT, 2004. Climate variability and vertical advection of nitrates in the Gulf of St. Lawrence, Canada. Mar. Ecol. Prog. Ser., 279: 33-43 .

Using a modeling approach, we constructed a time series to examine interannual variability in the spring nitrate concentrations in the surface layer of the Gulf of St. Lawrence (GSL) for the period 1947 to 2000. This 2-step modeling approach used the lower boundary of the cold intermediate layer (CIL), a persistent summer characteristic of the temperature profiles in the GSL, to infer interannual variations in the depth of the winter mixed layer. Using a linear model describing the distribution of nitrates at intermediate depths, we estimated a time series of spring nitrate concentration in the surface waters of the GSL for the period 1947 to 2000. This early spring time series showed interannual fluctuations in nitrate concentrations of about 1 order of magnitude, attributable to variability in winter convection. Such variability in the spring nitrate availability should have a significant impact on the ecosystem. Some elements that should be taken into account in any future attempt to validate this estimated nitrate time series are discussed.©2004 Inter-Research

PEPIN, P., B. PETRIE, J.-C. THERRIAULT, G. HARRISON, 2004. Summary of the Five-Year Review of the Atlantic Zone Monitoring Program;Sommaire de la revue de cinq ans du Programme de Monitorage de la Zone Atlantique. AZMP Bull. PMZA, 4: 9-12 .

Click to see all the text

SAUCIER, F.-J., M. STARR, M. HARVEY, J.-C. THERRIAULT, 2003. Expédition Mérica 2003. Suivi et étude du climat et de la productivité de la baie d’Hudson. Naturaliste Can., 128(1): 108-110 .

PLOURDE, S., J.J. DODSON, J.A. RUNGE, J.-C. THERRIAULT, 2002. Spatial and temporal variations in copepod community structure in the lower St. Lawrence Estuary, Canada. Mar. Ecol. Prog. Ser., 230: 211-224 .

THERRIAULT, J.-C., 2002. Le Programme de Monitorage de la Zone Atlantique. AZMP Bull. PMZA, 2: 1-2 .

Click to see all the text

THERRIAULT, J.-C., P.S. GALBRAITH, M. STARR, M. HARVEY, 2002. Intrusions of Labrador shelf waters into the Gulf of St. Lawrence and their potential influence on the plankton. AZMP Bull. PMZA, 2: 12-15 .

Click to see all the text

[Abstract only available in French]
Des données hydrographiques obtenues dans le golfe du Saint-Laurent (GSL) depuis 1996 suggèrent que les années 2001 et 2002 sont caractérisées par des intrusions particulièrement importantes d'eaux denses et froides provenant des côtes du Labrador. Ces intrusions ont significativement contribué aux températures estivales particulièrement basses de la couche intermédiaire froide (CIF) dans le GSL, en dépit de conditions hivernales relativement chaudes. Plusieurs changements dans la communauté planctonique peuvent être associés à ces intrusions d'eaux froides dans le Golfe. Le plus remarquable en 2001 est sans doute la première apparition en grande abondance de la diatomée Neodenticula seminae dans presque toutes les régions du Golfe. Ceci est très inhabituel parce que cette diatomée est normalement retrouvée dans le Pacifique Nord, et non pas dans le nord Atlantique. En raison de sa présence simultanée sur la côte du Labrador et dans le Golfe, il est fort probable que cette espèce du Pacifique ait été introduite dans le Golfe via le détroit de Belle-Isle par des processus d'advection à travers l'Arctique, en empruntant le courant du Labrador. Une autre observation qui supporte l'hypothèse d'une importante intrusion d'eaux froides dans le Golfe en 2001 est l'augmentation significative de l'abondance de l'amphipode arctique Themisto libellula. En effet, leur nombre qui passe de 0.17 ind.m-2 en septembre 2000 à 10 ind.m-2 en septembre 2001, ne peut être facilement expliqué que par cette intrusion. Ces introductions régulières d'espèces planctoniques arctiques dans le GSL ont probablement un impact significatif sur les niveaux supérieurs de la chaîne trophique tel que suggéré par la relation significative observée entre l'abondance annuelle moyenne de T. libellula et sa présence relative dans la diète de la morue entre 1996 et 2001.

THERRIAULT, J.-C., N. PAILLE, 2002. Oceanographic processes in the Estuary and Gulf. St. Lawrence Vision 2000 (Monitoring the state of the St. Laurence River, 21) 8 p. .

Click to see all the text

THERRIAULT, J.-C., N. PAILLE, 2002. Les processus océanographiques dans l'estuaire et le golfe. Saint-Laurent Vision 2000 (Suivi de l'état du Saint-Laurent, 21) 8 p. .

Click to see all the text

STARR, M., M. HARVEY, P.S. GALBRAITH, D. GILBERT, D. CHABOT, J.-C. THERRIAULT, 2002. Recent intrusion of Labrador Shelf waters into the Gulf of St. Lawrence and its influence on the plankton community and higher trophic levels. ICES C.M., 2002/N:16, 10 p .

Click to see all the text

CANADA. MINISTERE DES PÊCHES ET DES OCÉANS. RÉGION DU QUÉBEC. DIRECTION DES SCIENCES OCÉANIQUES, J.-C. THERRIAULT (éd.), 2001. Bulletin PMZA. Institut Maurice-Lamontagne, Mont-Joli, Québec, 2001- .

The AZMP annual Bulletin publishes English, French, and bilingual articles to provide oceanographers and fisheries scientist, habitat and environment managers as well as the general public with the latest monitoring information from the Atlantic Zone Monitoring Program (AZMP). The Bulletin presents an annual review of the general oceanographic conditions in the Northwest Atlantic region, including the Gulf of St. Lawrence, as well as AZMP-related information concerning particular events, studies, or activities that took place during the previous year.

CANADA. DEPT. OF FISHERIES AND OCEANS. QUEBEC REGION. DIRECTION OF OCEAN SCIENCES, J.-C. THERRIAULT (Éd.), 2001. AZMP bulletin. Maurice Lamontagne Institute, Mont-Joli, Quebec, 2001- .

The AZMP annual Bulletin publishes English, French, and bilingual articles to provide oceanographers and fisheries scientist, habitat and environment managers as well as the general public with the latest monitoring information from the Atlantic Zone Monitoring Program (AZMP). The Bulletin presents an annual review of the general oceanographic conditions in the Northwest Atlantic region, including the Gulf of St. Lawrence, as well as AZMP-related information concerning particular events, studies, or activities that took place during the previous year.

HARVEY, M., J.-C. THERRIAULT, N. SIMARD, 2001. Hydrodynamic control of late summer species composition and abundance of zooplankton in Hudson Bay and Hudson Strait (Canada). J. Plankton Res., 23(5): 481-496 .

B. PETRIE, J.-C. THERRIAULT, G. HARRISON, V. SOUKHOVTSEV, P. PEPIN, M. HARVEY, M. STARR, P. LAROUCHE, S. SAMEOTO, 2001. The Atlantic Zone Monitoring Program;Le programme de monitorage de la zone atlantique. AZMP Bull. PMZA, 1: 1-12 .

Click to see all the text

SAVENKOFF, C., A.F. VEZINA, S. ROY, B. KLEIN, C. LOVEJOY, J.-C. THERRIAULT, L. LEGENDRE, R. RIVKIN, C. BÉRUBÉ, J.-E. TREMBLAY, N. SILVERBERG, 2000. Export of biogenic carbon and structure and dynamics of the pelagic food web in the Gulf of St. Lawrence : Part 1. Seasonal variations. Deep-Sea Res., Part II, Top. Stud. Oceanogr. 47(3-4): 585-607 .

DESROSIERS, G., C. SAVENKOFF, M. OLIVIER, G. STORA, K. JUNIPER, A. CARON, J.-P. GAGNÉ, L. LEGENDRE, S. MULSOW, J. Grant, S. Roy, A. GREHAN, P. SCAPS, N. SILVERBERG, B. KLEIN, J.-É. TREMBLAY, J.-C. THERRIAULT, 2000. Trophic structure of macrobenthos in the Gulf of St. Lawrence and on the Scotian Shelf. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 663-697 .

VÉZINA, A.F., C. SAVENKOFF, S. ROY, B. KLEIN, R. RIVKIN, J.-C. THERRIAULT, L. LEGENDRE, 2000. Export of biogenic carbon and structure and dynamics of the pelagic food web in the Gulf of St. Lawrence Part 2. Inverse analysis. Deep-Sea Res., Part II , Top. Stud. Oceanogr., 47(3-4): 609-635 .

TIAN, R.C., A.F. VÉZINA, L. LEGENDRE, R.G. INGRAM, B. KLEIN, T. PACKARD, S. ROY, C. SAVENKOFF, N. SILVERBERG, J.-C. THERRIAULT, J.É. TREMBLAY, 2000. Effects of pelagic food-web interactions and nutrient remineralization on the biogeochemical cycling of carbon : a modeling approach. Deep-Sea Res., Part II, Top. Stud. Oceanogr. 47(3-4): 637-662 .

TREMBLAY, J.E., L. LEGENDRE, B. KLEIN, J.-C. THERRIAULT, 2000. Size-differential uptake of nitrogen and carbon in a marginal sea (Gulf of St. Lawrence, Canada): significance of diel periodicity and urea uptake. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 489-518 .

SIRON, R., B. PELCHAT, J.-C. THERRIAULT, 2000. L'Observatoire du Saint-Laurent : un nouveau maillon dans la diffusion des connaissances. Naturaliste can., 124(2): 62-65 .

PACKARD, T., W. CHEN, D. BLASCO, C. SAVENKOFF, A.F. VEZINA, R. TIAN, L. ST-AMAND, S.O. ROY, C. LOVEJOY, B. KLEIN, J.-C. THERRIAULT, L. LEGENDRE, R.G. INGRAM, 2000. Dissolved organic carbon in the Gulf of St. Lawrence. Deep-Sea Res., Part II , Top. Stud. Oceanogr., 47(3-4): 435-459 .

SAVARD, L., 2000. Comparison of in situ-and satellite-derived quantities of CDOM and chlorophyll A in the St. Lawrence Estuary and Gulf, Canada. 1 page in Ocean Optics XV Conference, Monaco, 16-20 October, 2000 .

LOVEJOY, C., L. LEGENDRE, J.-C. THERRIAULT, J.-É. TREMBLAY, B. KLEIN, R.G. INGRAM, 2000. Growth and distribution of marine bacteria in relation to nanoplankton community structure. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 461-487 .

DOYON, P., B. KLEIN, R.G. INGRAM, L. LEGENDRE, J.-É. TREMBLAY, J.-C. THERRIAULT, 2000. Influence of wind mixing and upper-layer stratification on phytoplankton biomass in the Gulf of St. Lawrence. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 415-433 .

COMEAU, M., M. STARR, G.Y. CONAN, G. ROBICHAUD, J.-C. THERRIAULT, 1999. Fecundity and duration of egg incubation for multiparous female snow crabs (Chionoecetes opilio) in the fjord of Bonne Bay, Newfoundland. Can. J. Fish. Aquat. Sci., 56: 1088-1095 .

Multiparous female snow crabs (Chionoecetes opilio) were collected by trap and Nephrops trawl in the fjord of Bonne Bay, Newfoundland, between April 1988 and August 1992 to study the fecundity and embryonic development. A relationship was established between the color of the egg mass and embryonic development. Fecundity was positively correlated with carapace width. A female of 67 mm carapace width can produce up to about 54 000 eggs. Egg mortality over the incubation period could reach 21 %, being greater in large females. Based on the bimodal distributions of embryonic developmental stages observed in the study, the female reproductive cycle was determined as 2 years and females probably only hatch two broods in their lifetime. Eggs hatch mainly in May and June.

STARR, M., J.A. RUNGE, J.-C. THERRIAULT, 1999. Effects of diatom diets on the reproduction of the planktonic copepod Canalus finmarchicus. Sarsia, 84: 379-389 .

THERRIAULT, J.-C., B. PETRIE, P. PEPIN, J. GAGNON, D. GREGORY, J. HELBIG, A. HERMAN, D. LEFAIVRE, M. MITCHELL, B. PELCHAT, J. RUNGE, D. SAMEOTO, 1998. Proposal for a northwest Atlantic zonal monitoring program. Can. Tech. Rep. Hydrogr. Ocean Sci., 194, 57 p .

Click to see all the text

A comprehensive monitoring program has been designed for the northwestern Atlantic with the aim of increasing the Department of Fisheries and Oceans's capacity to understand, describe, and forecast the state of the marine ecosystem and to quantify the changes in the oceans and the predator-prey relationships of marine resources. This report presents an overview of the current monitoring activities and identifies the fundamental elements of a zonal monitoring program, which includes 1) in situ multidisciplinary monitoring of biological, chemical, and physical variables at fixed stations and along transects; 2) remote sensing of sea-surface temperature and ocean colour; 3) measurements of sea level; 4) groundfish surveys in all regions; and 5) continuous plankton recorder (CPR) lines on the Newfoundland and Scotian shelves. The necessity is discussed for coordinated and standardised sampling protocols and data management activities. The importance of data analysis and interpretation is addressed as well as the need to designate committees that will be responsible for the management and coordination of zonal monitoring activities.

THERRIAULT, J.-C., B. PETRIE, P. PEPIN, J. GAGNON, D. GREGORY, J. HELBIG, A. HERMAN, D. LEFAIVRE, M. MITCHELL, B. PELCHAT, J. RUNGE, D. SAMEOTO, 1998. Proposition pour un programme zonal de monitorage de la région nord-ouest de l'Atlantique. Rapp. tech. can. hydrogr. sci. océan., 194, 69 p .

Click to see all the text

A comprehensive monitoring program has been designed for the northwestern Atlantic with the aim of increasing the Department of Fisheries and Oceans's capacity to understand, describe, and forecast the state of the marine ecosystem and to quantify the changes in the oceans and the predator-prey relationships of marine resources. This report presents an overview of the current monitoring activities and identifies the fundamental elements of a zonal monitoring program, which includes 1) in situ multidisciplinary monitoring of biological, chemical, and physical variables at fixed stations and along transects; 2) remote sensing of sea-surface temperature and ocean colour; 3) measurements of sea level; 4) groundfish surveys in all regions; and 5) continuous plankton recorder (CPR) lines on the Newfoundland and Scotian shelves. The necessity is discussed for coordinated and standardised sampling protocols and data management activities. The importance of data analysis and interpretation is addressed as well as the need to designate committees that will be responsible for the management and coordination of zonal monitoring activities.

JACQUES, A., N.T. O'NEILL, J.-C. THERRIAULT, 1998. Chlorophyll remote sensing potential in pigment-poor moderately turbid case II waters: lower St. Lawrence Estuary. Can. J. Remote Sensing, 24: 194-199 .

COMEAU, M., G. ROBICHAUD, M. STARR, J.-C. THERRIAULT, G.Y. CONAN, 1998. Mating of snow crab Chionoecetes opilio (O. Fabricius, 1788) (Decapoda, Majidae) in the fjord of Bonne Bay, Newfoundland. Crustaceana, 71: 925-941 .

COMEAU, M., G.Y. CONAN, F. MAYNOU, G. ROBICHAUD, J.-C. THERRIAULT, M. STARR, 1998. Growth, spatial distribution, and abundance of benthic stages of the snow crab (Chionoecetes opilio) in Bonne Bay, Newfoundland, Canada. Can. J. Fish. Aquat. Sci., 55: 262-279 .

The growth and spatial distribution of postlarval snow crab (Chionoecetes opilio) from a relatively unexploitated stock in Bonne Bay, Newfoundland (Gulf of St. Lawrence), were described from the analysis of size distributions from trawls and a dredge sampled between 1988 and 1993. Immature crabs molted twice a year for instars I-V and then molted annually until females reached a terminal molt at maturity (instar X or XI) and males a juvenile stage (instar VIII). Thereafter, juvenile males could molt to another juvenile size, skip a molt, or achieve a terminal molt at the onset of the morphometric differentiation of their claws depending on the relative abundance of mature males. The life expectancy of females and males was 13 and 19 years, respectively. Males should recruit to the commercial size of 95 mm carapace width at instar XII, 9 years or more after settlement. Relative abundance of early benthic to commercial-size individuals suggests that small immature crabs (instar V) migrate from shallow rocky to deep muddy bottoms. The patchy spatial distribution observed for the snow crab appeared to be determined more by substrate and intraspecific factors than by depth. Seasonal movements to shallow waters by larger animals was related to density- and temperature-dependent factors associated with the reproductive and growth cycle.

RIVKIN, R.B., L. LEGENDRE, D. DEIBEL, J.-E. TREMBLAY, B. KLEIN, K. CROCKER, S. ROY, N. SILVERBERG, C. LOVEJOY, F. MESPLÉ, N. ROMERO, M.R. ANDERSON, P. MATTHEWS, C. SAVENKOFF, A. VÉZINA, J.-C. THERRIAULT, J. WESSON, C. BÉRUBÉ, R.G. INGRAM, 1997. Measuring biogenic carbon flux in the ocean : response. Science (Wash.), 275: 554-555 .

THERRIAULT, J.-C., J. PLOURDE, 1997. Development of an environmental index for the detection of climate changes in the Gulf of St. Lawrence : ecological interpretation of first results and implications for future monitoring programs. Pages 226-231 in R.W. Shaw (ed.). Climate variability and climate change in Atlantic Canada : proceedings of a workshop, Halifax, Nova Scotia, 3-6 December 1996. Environment Canada - Atlantic Region, Bedford, Nova Scotia (Occasional report, 9) .

HARVEY, M., J.-C. THERRIAULT, N. SIMARD, 1997. Late-summer distribution of phytoplankton in relation to water mass characteristics in Hudson Bay and Hudson Strait (Canada). Can. J. Fish. Aquat. Sci., 54: 1937-1952 .

Descriptive and multivariate analytical methods were used to analyze the early September (1993) abundance and species composition of phytoplankton in relation to water mass characteristics in Hudson Bay and Hudson Strait. Four groups of stations distributed along well-defined environmental gradients characterizing the distribution of physical and chemical variables were identified. The first group, located in the most southern region of Hudson Bay, was strongly influenced by freshwater runoffs from James Bay and from the other major rivers around the bay and was characterized by a relatively phytoplankton biomass (chlorophyll a (Chl a > 1.0 µg.L-1 in the near-surface waters and by a phytoplankton assemblage equally dominated by small flagellates and dinoflagellates. The second group, located in an area northwest of the Belcher and Sleeper islands, was characterized by relatively well-mixed conditions where small diatoms composed about 50 % of the phytoplankton assemblage. The third group occupied the upper part of the bay and the entrance of the strait and was characterized by the lowest surface nutrient concentrations encounterd. A clear subsurface chlorophyll maximum dominated by small flagellates (>55 % of the assemblage) was observed in this region. The fourth group was located in the central part of the strait where the highest surface nutrient concentrations and phytoplankton biomass values Chl a > 2.0 µg.L-1 were observed. The phytoplankton assemblage there was clearly dominated by small diatoms (<80 %). These conditions are related to the presence of more intense tidal mixing in this region. The phytoplankton standing crop within this area was comparable with that observed during an autumn bloom situation in the most temperate regions of the world's oceans.

TREMBLAY, J.-E., L. LEGENDRE, J.-C. THERRIAULT, 1997. Size-differential effects of vertical stability on the biomass and production of phytoplankton in a large estuarine system. Estuar. Coast. Shelf Sci., 45(4): 415-431 .

TREMBLAY, J.-É., B. KLEIN, L. LEGENDRE, R.B. RIVKIN, J.-C. THERRIAULT, 1997. Estimation of ƒ-ratios in oceans based on phytoplankton size structure. Limnol. Oceanogr., 42(3): 595-601 .

NIEKE, B., W.F. VINCENT, J.-C. THERRIAULT, L. LEGENDRE, J.-F. BERTHON, A. CONDAL, 1997. Use of ship-borne laser fluorosensor for remote sensing of chlorophyll a in a coastal environment. Remote Sens. Environ., 60(2): 140-152 .

NIEKE, B., R. REUTER, R. HEUERMANN, H. WANG, M. BABIN, J.C. THERRIAULT, 1997. Light absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM), in the St. Lawrence Estuary (Case 2 waters). Cont. Shelf Res., 17(3): 235-252 .

SAVENKOFF, C., A. VÉZINA, J.-C. THERRIAULT, 1997. Le cycle du carbone dans le golfe du Saint-Laurent. Nouv. Sci., 8(7): 4-6 .

THERRIAULT, J.-C., D. GILBERT, P. LAROUCHE, D. LEFAIVRE, B. PELCHAT, 1997. L'estuaire et le golfe du Saint-Laurent scrutés de près. Le Fleuve : bull. d’inf., 8(1) : 2-4 .

Click to see all the text

[Abstract only available in French]
La mer n’est pas inépuisable. La chute des stocks de morue dans l’est du Canada et les manchettes faisant état depuis quelques années des difficultés des pêcheurs aux deux extrémités du pays ont puissamment contribué à sensibiliser le grand public à la nécessité de mieux connaître le milieu marin, si l’on veut en gérer les ressources durablement.©1997 Saint-Laurent Vision 2000

LEGENDRE, L., B. ROBINEAU, M. GOSSELIN, C. MICHEL, R.G. INGRAM, L. FORTIER, J.-C. THERRIAULT, S. DEMERS, D. MONTI, 1996. Impact of freshwater on a subarctic coastal ecosystem under seasonal sea ice (southeastern Hudson Bay, Canada). II, Poduction and export of microalgae. J. Mar. Syst., 7: 233-250 .

CONAN, G.Y., M. STARR, M. COMEAU, J.-C. THERRIAULT, F.X. MAYNOU, I. HERNANDEZ, G. ROBICHAUD, 1996. Life history strategies, recruitment fluctuations, and management of the Bonne Bay Fjord Atlantic snow crab (Chionoecetes opilio). Pages 59-97 in High latitude crabs : biology, management and economics. Alaska Sea Grant College Program (Alaska Sea Grant report; 96-02) .

PAINCHAUD, J., D. LEFAIVRE, J.-C. THERRIAULT, L. LEGENDRE, 1996. Bacterial dynamics in the upper St. Lawrence estuary. Limnol. Oceanogr., 41(8): 1610-1618 .

LOVEJOY, C., L. LEGENDRE, B. KLEIN, J.-É. TREMBLAY, R.G. INGRAM, J.-C. THERRIAULT, 1996. Bacterial activity during early winter mixing (Gulf of St. Lawrence, Canada). Aquat. Microbiol. Ecol., 10: 1-13 .

MONTI, D., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, 1996. Horizontal distribution of sea-ice microalgae : environmental control and spatial processess (southeastern Hudson Bay, Canada). Mar. Ecol. Prog. Ser., 133: 229-240 .

SAVENKOFF, C., A.F. VÉZINA, T.T. PACKARD, N. SILVERBERG, J.-C. THERRIAULT, W. CHEN, C. BÉRUBÉ, A. MUCCI, B. KLEIN, F. MESPLÉ, J.-E. TREMBLAY, L. LEGENDRE, J. WESSON, R.G. INGRAM, 1996. Distributions of oxygen, carbon, and respiratory activity in the deep layer of the Gulf of St. Lawrence and their implications for the carbon cycle. Can. J. Fish. Aquat. Sci., 53: 2451-2465 .

The Gulf of St. Lawrence (GSL) is a semi-enclosed sea with an estuarine circulation forced by runoff from the St. Lawrence and Great Lakes drainage systems and balanced by a deep inflow of oceanic waters through the Laurentian Channel. Based on samples collected between July 1992 and June 1994 during Phase 1 of the CJGOFS program conducted in the Gulf of St. Lawrence, new data are presented on the carbon and nutrient chemistry as well as respiratory activity in the deep waters. Organic carbon fluxes estimated from sediment trap data, deepwater respiratory activity, and benthic respiration measurements are consistent with those obtained from the changes in the dissolved oxygen concentration of the deep waters along the Laurentian Channel. These flux estimates suggest that approximately 10 % of the local primary production reaches the deep layer (> 200 m) and the sediments in the GSL. The vertical carbon budget is almost balanced in the eastern part of the gulf, but approximately half of the carbon produced in the surface layer of the northwestern gulf cannot be accounted for. The difference in hydrodynamic and biological conditions prevailing in both areas may explain the observations.

SIMARD, N., J.-C. THERRIAULT, P. LAROUCHE, A. VÉZINA, J. PLOURDE, J. PERCY, D.A. STEEL, 1996. Données d'océanographie physique et biologique recueillies dans l'est et le nord de la baie d'Hudson et dans le détroit d'Hudson en août et septembre 1993. Rapp. stat. can. sci. halieut. aquat., 978, 199 p .

Click to see all the text

This report presents physical and biological oceanograpahic data of the eastern and northern parts of Hudson Basin that were obtained during a sampling mission of 84 stations conducted between 22 August and l5 September l993. A summary table identifies variables measured at each station. The vertical profiles of temperature, salinity, in situ fluorescence, chlorophyll a, particulate organic carbon and nitrogen, and nutrients are presented as well as phytoplankton and zooplankton counts and zooplankton biomass determination. Photosynthetic parameters calculated from P-l curves and estimates of total primary production at the surface are also provided. (DBO).

STARR, M., J.A. RUNGE, J.-C. THERRIAULT, 1996. Harmful effects of certain diatoms on the reproductive success of copepods. Pages 128-134 in R.W. Penney (ed.). Proceedings of the Fifth Canadian Workshop on Harmful Marine Algae. Dept. of Fisheries and Oceans (Can. Tech. Rep. Fish. Aquat. Sci., 2138) .

DIONNE, E., J.N. GEARING, N. BERTRAND, P.J. GEARING, J.-C. THERRIAULT, J. PLOURDE, 1996. Répartition de certains hydrocarbures dans le seston de l'estuaire du Saint-Laurent et du fjord du Saguenay, 1990. Rapp. stat. can. sci. halieut. aquat., 977, 186 p .

Click to see all the text

This report lists the concentrations of polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and chlorinated hydrocarbons extracted from different size fractions of suspended particles in the St. Lawrence Estuary and the Saguenay Fjord in l990. (DBO).

RIVKIN, R.B., L. LEGENDRE, D. DEIBEL, J.-É. TREMBLAY, B. KLEIN, K. CROCKER, S. ROY, N. SILVERBERG, C. LOVEJOY, F. MESPLÉ, N. ROMERO, M.R. ANDERSON, P. MATTHEWS, C. SAVENKOFF, A. VÉZINA, J.-C. THERRIAULT, J. WESSON, C. BÉRUBÉ, R.G. INGRAM, 1996. Vertical flux of biogenic carbon in the ocean : is there food web control?. Science (Wash.), 272: 1163-1166 .

NIEKE, B., J.-C. THERRIAULT, W.F. VINCENT, J.-F. BERTHON, L. LEGENDRE, A. CONDAL, 1995. Influence of PAR on a laser fluorosensor (LIDAR) signal of in vivo chlorophyll a fluorescence. Pages 117-121 in G. Guyot (ed.). Proceedings of the International Colloquium on Photosynthesis and Remote Sensing, 28-30 August 1995, Montpellier (France) .

PAINCHAUD, J., D. LEFAIVRE, J.-C. THERRIAULT, L. LEGENDRE, 1995. Physical processes controlling bacterial distribution and variability in the upper St. Lawrence Estuary. Estuar. Coasts, 18: 433-444 .

The vertical structure of the water column and the spatial distribution and semidiurnal variability of bacteria were investigated at six stations in the upper St. Lawrence estuary. The sigmat profiles indicate that the upper St. Lawrence is a partially mixed estuary. Stratification results from buoyancy input from the freshwater outflow of the St. Lawrence River, and its variability is controlled by tidal and, to a lesser extent, wind mixing. Calculations show that tidal mixing largely exceeds mixing caused by wind. Free and attached bacteria presented different patterns of spatial distribution and temporal variability. Free bacteria exhibited highest mean concentrations at the freshwater station (3.5-4.4 106 ml-1) and lowest concentrations at the downstream stations (0.3-0.5 106 ml-1); their numbers declined exponentially relative to salinity. Attached bacteria had highest mean concentrations (3.2-5.5 106 ml-1) at salinities between 0.5 and 5 and were virtually absent at downstream stations (<0.05 106 ml-1). The importance of semidiurnal variability was demonstrated. Over the tidal cycle, variability of attached bacteria was always greater than that of free bacteria. The analysis of causal models between salinity and free and attached bacteria, showed that the two types of bacteria are uncoupled and that both types have a strong relationship with salinity. Physical processes are thus important controlling factors of the distribution and variability of bacteria. Results suggest that large-scale processes, such as freshwater outflow and residual circulation, largely control free bacteria, whereas short-term and more local processes (e.g., sediment resuspension caused by wind) may also be important in the control of attached bacteria.©1995 Springer

NIEKE, B., A. CONDAL, J.-F. BERTHON, C. BELLEHUMEUR, L. LEGENDRE, S. MORIN, J.-C. THERRIAULT, C. GIROUD, R. DICK, 1995. Depth resolved detection of oceanographic variables in the St. Lawrence Estuary using a laser fluorosensor : instrument characteristics and first results. Int. J. Remote Sens., 16: 1503-1522 .

PAINCHAUD, J., J.-C. THERRIAULT, L. LEGENDRE, 1995. Assessment of salinity-related mortality of freshwater bacteria in the Saint Lawrence estuary. Appl. Environ. Microbiol., 61: 205-208 .

BABIN, M., J.-C. THERRIAULT, L. LEGENDRE, B. NIEKE, R. REUTER, A. CONDAL, 1995. Relationship between the maximum quantum yield of carbon fixation and the minimum quantum yield of chlorophyll a in vivo fluorescence in the Gulf of St. Lawrence. Limnol. Oceanogr., 40: 956-968 .

SMITH, R.E.H., S. DEMERS, H. HATTORI, S. KUDOH., L. LEGENDRE, C. MICHEL, M. GOSSELIN, B. ROBINEAU, S. SUZUKI, M. TAKAHASHI, J.-C. THERRIAULT, S.K. JUNIPER, T. SIME-NGANDO, 1995. Biological and chemical investigations of the Saroma-Resolute Project in ice-covered Resolute Passage, 1992. Can. Data Rep. Hydrogr. Ocean Sci., 137, 19 p .

Click to see all the text

Samples for biological and chemical analysis were taken from annual sea ice and the underlying water column from early April to late May of 1992 in Resolute Passage to elucidate the processes of biological production and their implications for carbon cycling in ice-covered seas. The sampling program covered the main period of the annual bloom of ice algae. The principal measurements included inorganic nutrients; pigments; particulate organic carbon and nitrogen; dissolved organic carbon; bacterial, microheterotrophic, nanoprotozoan, and zooplankton abundances; primary production; and nanoprotozoan feeding rates. Plots are provided to illustrate the seasonal progression of snow and ice cover, irradiance, pigment concentrations, and POC and PON in the ice. The results of most measurements are reported in tables and are also available upon request as spreadsheet files on diskette.

STARR, M., J.-C. THERRIAULT, G.Y. CONAN, M. COMEAU, G. ROBICHAUD, 1994. Is match/mismatch the universal ill fated mechanism de-regulating stock/recruitment models? Snow crab (Chionoecetes opilio) prove that some species may precisely sense optimal plankton production for a timely release of their larvae. ICES C.M., 1994/R:12, 20 p .

ROBINEAU, B., L. LEGENDRE, J.-C. THERRIAULT, L. FORTIER, G. ROSENBERG, S. DEMERS, 1994. Ultra-algae (< 5 µ) in the ice, at the ice-water interface and in the under-ice water column (southeastern Hudson Bay, Canada). Mar. Ecol. Prog. Ser., 115: 169-180 .

STARR, M., J.-C. THERRIAULT, G.Y. CONAN, M. COMEAU, G. ROBICHAUD, 1994. Larval release in a sub-euphotic zone invertebrate triggered by sinking phytoplankton particles. J. Plankton Res., 16: 1137-1147 .

STARR, M., J.H. HIMMELMAN, J.-C. THERRIAULT, 1993. Environmental control of green sea urchin, Strongylocentrotus droebachiensis, spawning in the St. Lawrence Estuary. Can. J. Fish. Aquat. Sci., 50: 894-901 .

BABIN, M., J.-C. THERRIAULT, L. LEGENDRE, A. CONDAL, 1993. Variations in the specific absorption coefficient for natural phytoplankton assemblages : impact on estimates of primary production. Limnol. Oceanogr., 38: 154-177 .

DEMERS, S., J.-C. THERRIAULT, 1993. Quand les océans pompent le CO2. Interface, 14(3): 14-25 .

MICHEL, C., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, T. VANDEVELDE, 1993. Springtime coupling between ice algal and phytoplankton assemblages in southeastern Hudson Bay, Canadian Arctic. Polar Biol., 13: 441-449 .

O'NEILL, N.T., A. JACQUES, J.-C. THERRIAULT, 1993. Lidar 92 : une étude préliminaire sur les facteurs influençant la spectroradiométrie passive en eaux de type Case II. Pages 125-129 in P. Gagnon & N. O'Neill (éd.). 16e symposium canadien sur la télédétection et 8e congrès de l'Association québécoise de télédétection. Metrolitho, Sherbrooke .

THERRIAULT, J.-C., L. LEGENDRE, N.T. O'NEILL, A. CONDAL, P. LEGENDRE, 1993. Télédétection active et passive : un programme de recherche multidisciplinaire pour estimer la production primaire dans les eaux côtières et estuariennes du Saint-Laurent. Pages 257-262 in P. Gagnon & N. O'Neill (éd.). 16e Symposium canadien sur la télédétection et 8e Congrès de l'Association québécoise de télédétection. Metrolitho, Sherbrooke .

FORTIER, L., M.E. LEVASSEUR, R. DROLET, J.-C. THERRIAULT, 1992. Export production and the distribution of fish larvae and their prey in a coastal jet frontal region. Mar. Ecol. Prog. Ser., 85: 203-218 .

STARR, M., J.H. HIMMELMAN, J.-C. THERRIAULT, 1992. Isolation and properties of a substance from the diatom Phaeodactylum tricornutum which induces spawning in the sea urchin Strongylocentrotus droebachiensis. Mar. Ecol. Prog. Ser., 79: 275-287 .

PERCY, R., M. FINGAS, J.-C. THERRIAULT, 1992. A laser environmental airborne fluorosensor for detection and mapping of oil spills on water, ice and shorelines, and of chlorophyll and other environmental variables in near surface water. Environment Canada. Conservation and Protection, 7 p .

Offshore exploration drilling for oil and gas has been taking place in Canada for over a decade and production is imminent. Tanker traffic in Canadian waters is increasing. Past experience has shown that increased spillage of oil usually accompanies such increases in activity. If the environment is to be protected, it is essential that complete and timely information, on oil spill position and extent, be readily available to commanders of clean-up operations. Since 1987, Environment Canada, Environmental Protection, supported by API, The Canadian Panel on Energy Research (PERD) the U.S. Minerals Management Service, Fisheries and Oceans Canada, Canada Centre for Remote Sensing and the United States Coast Guard, has sponsored a programme to develop and test instrumentation capable of detection and mapping spilled oil, on water, shorelines and ice, and chlorophyll and other environmental variables in near surface waters. A prototype Laser Environmental Airborne Fluorosensor (LEAF) has been constructed and flight testedunder controlled conditions. It has demonstrated reliable discrimination capability for crude oil on water, rocks, sand, gravel, and ice. Longer wavelength capacity is under development for measurement of environmental variables that have useful application in oceanography.©1992 Environment Canada

SMITH, J.C., N. BOUCHARD-STEEVES, D. BLASCO, M. LEMAY, A. GERVAIS, R. GELINAS, S. GOSSELIN, B. HUPPERTZ, P. KEIZER, C.M. YENTSCH; C. POWELL, S. HANCOCK, K.H. MANN, J. MARTIN, L. BÉRARD-THERRIAULT, J.-C. THERRIAULT, E. BERDALET, 1992. Monitoring toward year 2000. Pages 91-104 in J.-C. Therriault & M. Levasseur (ed.). Proceedings of the Third Canadian Workshop on Harmful Marine Algae, Maurice-Lamontagne lnstitute, Mont-Joli, Québec, 12-14 May, 1992 .

Click to see all the text

LEGENDRE, L., M.-J. MARTINEAU, J.-C. THERRIAULT, S. DEMERS, 1992. Chlorophyll a biomass and growth of sea-ice microalgae along a salinity gradient (southeastern Hudson Bay, Canadian Arctic). Polar Biol., 12: 445-453 .

LEVASSEUR, M., L. FORTIER, J.-C. THERRIAULT, P.J. HARRISON, 1992. Phytoplankton dynamics in a coastal jet frontal region. Mar. Ecol. Prog. Ser., 86: 283-295 .

THERRIAULT, J.-C., M. LEVASSEUR (ed.), 1992. Proceedings of the Third Canadian Workshop on Harmful Marine Algae, Maurice Lamontagne Institute, Mont-Joli, Quebec, 12-14 May, 1992. Can. Tech. Rep. Fish. Aquat. Sci., 1893,154 p .

Click to see all the text

The Third Canadian Workshop on Harmful Marine Algae was hosted by the Department of Fisheries and Oceans, Québec region, at the Maurice Lamontagne Institute, Mont-Joli, on 12-14 May 1992. The workshop was attended by over 80 canadian and foreign participants and was aimed at a more efficient exchange of information on the latest developments concerning the subject of marine harmful algae in canadian waters. The main focus of the Workshop was "Harmful Algal Products : Impacts on the Food Web, Fisheries and Aquaculture". The present proceedings contain : 1) the abstracts of the oral and poster presentation; 2) the six reports from the Working Groups that were set up for general discussion on the following subjects : Origin and Propagation of Harmful Algae, Transfer of Phycotoxins in the Food Web, Detection and Quantification of Toxic Algae and Toxins, and Monitoring and Prediction of Harmful Events; 3) a conclusion chapter summarizing and emphasizing the most important recommendations from the Working Groups; and finally, in annex 4) two reviews highlighting the monitoring and phycotoxin programs in each DFO region, accompanied by a listing of National Working Hypotheses. A list of participants and an index of authors complete the proceedings.

THERRIAULT, J.-C. (éd.), 1991. Le Golfe du Saint-Laurent : petit océan ou grand estuaire? ; The Gulf of St. Lawrence : small ocean or big estuary?. Ministère des pêches et des océans (Publ. Spéc. Can. Sci. Halieut. Aquat., 113), 359 p .

RUNGE, J.A., J.-C. THERRIAULT, L. LEGENDRE, R.G. INGRAM, S. DEMERS, 1991. Coupling between ice microalgal productivity and the pelagic, metazoan food web in southeastern Hudson Bay : a synthesis of results. Polar Res., 10(2): 325-338 .

ROCHE-MAYZAUD, O., J.-C. THERRIAULT, J.A. RUNGE, Y. De LAFONTAINE, 1991. Variations de l'activité des enzymes digestives et de la ponte chez les femelles de Calanus finmarchicus dans le golfe du Saint-Laurent. Pages 231-240 in J.-C. Therriault (éd.). Le Golfe du Saint-Laurent : petit océan ou grand estuaire? Ministère des pêches et des océans (Publ. spéc. can. sci. halieut. aquat., 113) .

BABIN, M., J.-C. THERRIAULT, L. LEGENDRE, 1991. Potential utilization of temperature in estimating primary production from remote sensing data in coastal and estuarine waters. Estuar. Coast. Shelf Sci., 33: 559-579 .

STARR, M., J.H. HIMMELMAN, J.-C. THERRIAULT, 1991. Coupling of nauplii release in the barnacles with phytoplankton blooms : a parallel strategy to that of spawning in urchins and mussels. J. Plankton Res., 13: 561-571 .

RUNGE, J.A., J.-C. THERRIAULT, L. LEGENDRE, R.G. INGRAM, S. DEMERS, 1991. Coupling between ice microalgal productivity and the pelagic, metazoan food web in southeastern Hudson Bay : a synthesis of results. Pages 325-338 in E. Sakshaug, C.C.E. Hopkins & N.A. Oritsland (ed.). Proceedings of the Pro Mare Symposium on Polar Marine Ecology. Trondheim, 12-16 May 1990 .

LEVASSEUR, M.E., P.J. HARRISON, B.R. HEIMDAL, J.-C. THERRIAULT, 1990. Simultaneous nitrogen and silicate deficiency of a phytoplankton community in a coastal jet-front. Mar. Biol., 104: 329-338 .

MICHEL, C., L. LEGENDRE, S. DEMERS, J.-C. THERRIAULT, 1990. Photoadaptation of sea-ice microalgae in springtime : photosynthesis and carboxylating enzymes. Mar. Ecol. Prog. Ser., 50: 177-185 .

STARR, M., J. HIMMELMAN, J.-C. THERRIAULT, 1990. Direct coupling of marine invertebrate spawning with phytoplankton blooms. Science (Wash.), 247: 1071-1074 .

THERRIAULT, J.-C., L. LEGENDRE, S. DEMERS, 1990. Oceanography and ecology of phytoplankton in the St. Lawrence Estuary. Pages 269-295 in M. El-Sabh & N. Silverberg (ed.). Oceanography of a large-scale estuarine system : the St. Lawrence. Springer-Verlag, Berlin (Coastal and estuarine studies, 39) .

TURGEON, J., A.D. CEMBELLA, J.-C. THERRIAULT, P. BÉLAND, 1990. Spatial distribution of resting cysts of Alexandrium spp. in sediments of the Lower St. Lawrence Estuary and the Gaspé coast. Pages 238-243 in E. Graneli, B. Sundström, L. Edler & D.M. Anderson (ed.). Toxic marine phytoplankton. Elsevier Science, New York .

GOSSELIN, M., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, 1990. Light and nutrient limitation of sea-ice microalgae (Hudson Bay, Canadian Arctic). J. Phycol., 26: 220-232 .

PAINCHAUD, J., D. LEFAIVRE, G.-H. TREMBLAY, J.-C. THERRIAULT, 1990. Analysis of the distribution of suspended particulate matter, bacteria, chlorophyll a and Po4 in the Upper St. Lawrence Estuary, using a two-dimensional box model. Pages 59-65 in W. Michaelis (ed.). Estuarine water quality management : monitoring, modelling and research. Springer-Verlag, New York (Coastal and estuarine studies, 36) .

THERRIAULT, J.-C., J. PAINCHAUD, P. HODSON, M. CASTONGUAY, G. WALSH, J. GEARING, M. KINGSLEY, B. TESSIER, 1990. Le plan d'action Saint-Laurent à la Direction des sciences, Institut Maurice-Lamontagne : orientations et objectifs. Rapp. manus. can. sci. halieut. aquat., 2055, 15 p .

Click to see all the text

The authors from the Maurice Lamontagne Institute, Quebec, Canada, present a research plan that will add to their knowledge of the causes and effects of the chemical pollution of the St. Lawrence River.

HUDON, C., M. ALLARD, F. AXELSEN, R. CRAWFORD, K. DRINKWATER, S. LABONTÉ, D. McALLISTER, P. RICHARD, L. ROY, A. SINCLAIR, J.-C. THERRIAULT, 1990. Report of fish and commercial invertebrates working group. Pages 29-32 in J.A. Percy (ed.). Proceedings of a workshop : Marine Ecosystem Studies in Hudson Strait, November 9-10, 1989, Montréal, Québec. Dept. of Fisheries and Oceans (Can. Tech. Rep. Fish. Aquat. Sci., 1770) .

Click to see all the text

THERRIAULT, J.-C., D. BOOTH, L. LEGENDRE, S. DEMERS, 1990. Phytoplankton photoadaptation to vertical excursion as estimated by an in vivo fluorescence ratio. Mar. Ecol. Prog. Ser., 60: 97-111 .

PAINCHAUD, J., J.-C. THERRIAULT, 1989. Relationships between bacteria, phytoplankton and particulate organic carbon in the Upper St. Lawrence Estuary. Mar. Ecol. Prog. Ser., 56: 301-311 .

DEMERS, S., J.-C. THERRIAULT, E. BOURGET, H. DÉSILETS, 1989. Small-scale gradients of phytoplankton productivity in the littoral fringe. Mar. Biol., 100: 393-399 .

CEMBELLA, A.D., J.-C. THERRIAULT, 1989. Population dynamics and toxin composition of Protogonyaulax tamarensis from the St. Lawrence Estuary. Pages 81-84 in T. Okaichi, D.M. Anderson & T. Nemoto (ed.). Red tides : biology, environmental science and toxicology. Elsevier, New York .

MICHEL, C., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, 1989. Photosynthetic responses of arctic sea-ice microalgae to short-term temperature acclimation. Polar Biol., 9: 437-442 .

LEGENDRE, L., S. DEMERS, J.-C. THERRIAULT, 1989. Responses of Arctic sea-ice microalgae to light and temperature : physiological adaptations and ecological implications. Rapp. P-v. Réun. CIEM, 188: 115-120 .

DESILETS, H., J. PAINCHAUD, J.-C. THERRIAULT, 1989. Abondance, composition spécifique et biomasse du phytoplancton de l'Estuaire moyen du Saint-Laurent. Rapp. tech. can. sci. halieut. aquat., 1698, 65 p .

Click to see all the text

This report contains abundance and specific composition data of 49 phytoplankton samples from the Upper St. Lawrence Estuary (summer 1982). Smayda's (1978) method for estimating phytoplankton biomass was applied to these data. Although more time-consuming, the plasma volume method yields a better image of phytoplankton biomass than traditional methods. Phytoplankton abundance is highest at the station located in the Lower Estuary; however, it decreases to considerably lower values in the Upper Estuary. Phytoplankton abundance reaches again higher levels in fresh water. In the Upper Estuary, microflagellates dominate the phytoplankton community. Biomass follows a similar pattern : it is highest in the Lower Estuary, lowest in the Upper Estuary and intermediate in fresh water. Ciliated protozoans are observed at all stations. Our observations suggest that the study area is not favorable for the development of local phytoplankton communities.

THERRIAULT, J.-C., S. DEMERS, L. LEGENDRE, R.G. INGRAM, J. RUNGE, 1989. Physical control of biological production at the seasonal sea-ice/water interface and in the underlying water column in Hudson Bay (Canada). Page 123 in G. Hempel (ed.). Oceanography and biology of Arctic seas. International Council for the Exploration of the Sea (Rapp. P.-v. Réun. CIEM, 188) .

DEMERS, S., J.-C. THERRIAULT, L. LEGENDRE, 1989. Responses of sea-ice microalgae to nutrients. Page 122 in G. Hempel (ed.). Oceanography and biology of Arctic seas. International Council for the Exploration of the Sea (Rapp. P.-v. Réun. CIEM, 188) .

VANDEVELDE, T., L. LEGENDRE, S. DEMERS, J.-C. THERRIAULT, 1989. Circadian variations in photosynthetic assimilation and estimation of daily phytoplankton production. Mar. Biol., 100: 525-531 .

CEMBELLA, A.D., J.-C. THERRIAULT, P. BÉLAND, 1988. Toxicity of cultured isolates and natural populations of Protogonyaulax tamarensis from the St. Lawrence Estuary. J. Shellfish Res., 7: 611-621 .

CEMBELLA, A.D., F.J.R. TAYLOR, J.-C. THERRIAULT, 1988. Cladistic analysis of electrophoretic variants within the toxic dinoflagellates genus Protogonyaulax. Bot. Mar., 31: 39-51 .

CEMBELLA, A.D., J. TURGEON, J.-C. THERRIAULT, P. BÉLAND, 1988. Spatial distribution of Protogonyaulax tamarensis resting cysts in nearshore sediments along the north coast of the Lower St. Lawrence Estuary. J. Shellfish Res., 7: 597-609 .

LEGENDRE, L., S. DEMERS, C. GARSIDE, E. M. HAUGEN, D. A. PHINNEY, L.P. SHAPIRO, J.-C. THERRIAULT, C.M. YENTSCH, 1988. Circadian photosynthetic activity of natural marine phytoplankton isolated in a tank. J. Plankton Res., 10: 1-6 .

VANDEVELDE, T., L. LEGENDRE, S. DEMERS, J.-C. THERRIAULT, 1988. Interrelationship between in vivo fluorescence of phytoplankton and light beam transmission with reference to fluorescence yield. Can. J. Fish. Aquat. Sci., 45: 1508-1513 .

BARLOW, R.G., M. GOSSELIN, L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, C.A. LLEWELLYN, R.F.C. MANTOURA, 1988. Photoadaptive strategies in sea-ice microalgae. Mar. Ecol. Prog. Ser., 45: 145-152 .

DEMERS, S., J.-C. THERRIAULT, E. BOURGET, A. BAH, 1987. Resuspension in the shallow sublittoral zone of a macrotidal estuarine environment : wind influence. Limnol. Oceanogr., 32(2): 327-339 .

Several biological and physical variables were measured four times daily for 148 consecutive days at a fixed station to examine fluctuations of phytoplankton abundance in the littoral zone of the lower St. Lawrence estuary. On the seasonal scale, the pattern of variation of phytoplankton was characterized by a midsummer diatom bloom similar to that observed ofshore in the pelagic zone. On the shorter time scale, chlorophyll a concentration in the littoral zone was highly variable and closely associated with variations in the wind field. No relationship, however, could be found between phytoplankton cell numbers and wind velocity. The possible influence of wind, tidal-induced upwelling, overturning eddies, and wave-induced mixing processes on resuspension was examined. The higher Chl a values observed irregularly at the sampling stations resulted from the mechanical resuspension of benthic diatoms due to wind, or wind-induced wave, mixing in the littoral zone. Wind velocities >4 m s -1 were shown to cause significant resuspension of particulate organic matter (POC) in the water column. For winds >6 m s -1, there was no further increase in POC. These results suggest that the frequency of wind velocities >4 m s -1 plays a significant role on secondary production in the littoral zone by providing an increased food supply to benthic and planktonic filter feeders, especially at times when phytoplankton biomass is normally low in the water column.©1987 American Society of Limnology and Oceanography, Inc.

VANDEVELDE, T., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, A. BAH, 1987. Subsurface chlorophyll maximum and hydrodynamics of the water column. J. Mar. Res., 45: 377-396 .

PAINCHAUD, J., D. LEFAIVRE, J.-C. THERRIAULT, 1987. Box model analysis of bacterial fluxes in the St. Lawrence Estuary. Mar. Ecol. Prog. Ser., 41: 241-252 .

LEVASSEUR, M.E., J.-C. THERRIAULT, 1987. Phytoplankton biomass and nutrient dynamics in a tidally induced upwelling : the role of the NO3> :  SiO4 ratio. Mar. Ecol. Prog. Ser., 39: 87-97 .

DEMERS, S., L. LEGENDRE, J.-C. THERRIAULT, 1986. Phytoplankton responses to vertical tidal mixing. Pages 1-40 in M.J. Bowman, C.M. Yentsch & W.T. Peterson (ed.). Tidal mixing and plankton dynamics. Springer-Verlag, Berlin (Lecture notes on coastal and estuarine studies,17) .

THERRIAULT, J.-C., M. LEVASSEUR, 1986. Freshwater runoff control of the spatio-temporal distribution of phytoplankton in the Lower St. Lawrence Estuary (Canada). Pages 251-260 in S. Skreslet (ed.). The role of freshwater ouflow in coastal marine ecosystems. Springer-Verlag, Berlin (NATO Advanced Study Institutes Series. Series G, Ecological Sciences, 7) .

SINCLAIR, M., G.L. BUGDEN, C.L. TANG, J.-C. THERRIAULT, P.A. YEATS, 1986. Assessment of effects of freshwater runoff variability on fisheries production in coastal waters. Pages 139-160 in S. Skreslet (ed.). The role of freshwater outflow in coastal marine ecosystems. Springer-Verlag, Berlin (NATO Advanced Study Institutes Series. Series G, Ecological Sciences, 7) .

SIMARD, Y., R. DE LA DURANTAYE, J.-C. THERRIAULT, 1986. Aggregation of euphausiids along a coastal shelf in an upwelling environment. Mar. Ecol. Prog. Ser., 32: 203-215 .

GOSSELIN, M., L. LEGENDRE, J.-C. THERRIAULT, S. DEMERS, M. ROCHET, 1986. Physical control of the horizontal patchiness of sea-ice microalgae. Mar. Ecol. Prog. Ser., 29: 289-298 .

DEMERS, S., L. LEGENDRE, J.-C. THERRIAULT, R.G. INGRAM, 1986. Biological production at the ice-water ergoclines. Pages 31-54 in J.C.J. Nihoul (ed.). Marine interfaces ecohydrodynamics. Elsevier, Amsterdam (Elsevier Oceanography Series, 42) .

The ice-water interface is the site of high microalgal productivity. These microalgae constitute an important part of the productivity of polar seas. The growth of ice microalgae during the spring and perhaps during the autumn extends the short growing season in the water column. Herbivores have been observed to actively feed on the ice microalgae. Sea-ice microalgae respond to variations in salinity (which controls biomass and taxonomic composition in coastal areas influenced by freshwater runoff), temperature (the survival of microalgae depends on their ability to develop a protection mechanism against freezing), light (the photosynthetic activity of ice microalgae is a function of both light intensity and quality) and nutrients (nutrient limitation has been demonstrated even when ambient nutrient concentrations were high). The biological production at this energetic interface is examined in the specific context of the ice-water ergocline.