Marine Biology Research Literature

Selected Review of Marine Biology Literature

The following gives a brief description of some of the scientific literature which was encountered when researching St. Georges Bay. The descriptions contain the papers' abstracts as well as other notable information.

Bird, C.J., T. Edelstein and J. McLachlan (1987). Investigation of the marine algae of Nova Scotia. XII. The flora of Pomquet Harbour. Canadian Journal of Botany 54: 2726-2737.

Abstract: The benthic algal flora of Pomquet Harbour, a sheltered embayment of the lower Gulf of St. Lawrence, was observed over 10 years. Thirty-nine taxa of Chlorophyceae, 32 of Rhodophyceae, 44 of Phaeophyceae, 5 of Xanthophyceae, and 1 taxon of Chrysophyceae are recorded, and data on time of occurrence, reproduction, and hosts are given. Five species, Stichococcus bacillaris, Ulothrix subflaccidda, Vaucheria arcassonensis, V. compacta, and V. coronata, are reported as new to Nova Scotia.

Bird, C.J., T. Edelstein and J. McLachlan (1987). Studies on Gracilaria occurrence in Atlantic Canada with particular reference to Pomquet Harbour, Nova Scotia. Le Naturaliste Canadien 104: 257-266.

Abstract: Gracilaria sp. in Atlantic Canada occurs almost exclusively in the southern Gulf of St. Lawrence, with major populations in southeastern New Brunswick, the Magdalen Islands, and various points on the northern shores of Nova Scotia and Prince Edward Island. Occurrence is restricted to sheltered embayments having summer temperatures >20 degrees Celsius, salinity >20 parts per thousand, moderate circulation and firm sandmud substratum. Populations are mostly free-living, with plants attached by holdfasts being restricted to areas of firm, unsilted bottom; predominance of unattached plants is attributed to the nature of typical substratum in the habitat. In Pomquet Harbour, seasonal movement of an unattached population was mapped from May to October, while average density increased from 0,5 to 1,8 kg/m² during that period. Tetrasporogenesis in most populations was maximal in July or August, and a small percentage of fertile, usually attached gametophytes occurred throughout summer. It is suggested that prevalence of tetrasporophytes is due chiefly to superior longevity, and that reproduction of such populations is largely by vegetative growth.

Bird, C.J., T. Edelstein and J. McLachlan (1987). Studies on Gracilaria . Experimental Observations on growth and reproduction in Pomquet Harbour, Nova Scotia. Le Naturaliste Canadien 104: 245-255.

Abstract: Gracilaria sp. incubated during June-October at 0,4m depth in open mesh baskets in an estuarine embayment underwent an initial rapid gain in weight, followed by diminishing gains or losses. The largest increases occurred in July and August, when gains usually exceeded 100% during the first two weeks. Experimental material was generally more proliferous than contemporary field plants, and became fertile earlier. Similar results were noted in individual fronds tethered at 0,5-1,0m depth. Sporelings grew well at 0,5-1,0m depth, and usually became fertile during the summer, but growth declined below 1,0 to virtually nil at 3,0m, and outplants below 2,0m did not attain reproductive maturity in that season. Cystocarpic fronds were ephemeral during early summer, but cystocarps produced after August persisted through October. All outplants left to overwinter, including cystocarpic fronds, were in good condidtion in spring, and grew or regenerated readily with the onset of summer. Percentage dry weight, protein and carbohydrate were minimal during the period of active growth. Salinity during the experimental perriod was 23-28 parts per thousand with minimum values of 10-18 parts per thousand noted in April and May, while levels of nitrate and phosphorous peaked in late spring and late August.

Caddy, J. F., T. Amaratunga et al. (1977). 1975 Northumberland Strait Project, Part 1: Benthic fauna, flora, demersal fish, and sedimentary data. Fisheries and Marine Service Manuscript Report No. 1431: 46p.

Abstract: The purpose of the 1975 Northumberland Strait Project was to provide a baseline description of the physical and biological environment of the Strait in relation to the commercial shellfish resources. The resulting physical and biological data are presented in this, the first of two data-repository reports.

In the 8 1/2 week survey, 96 stations were sampled for fauna and flora with a van Veen grab and a beam trawl or scallop dredge. Species lists show distribution and empirical estimates of abundance of polychaetes, amphipods and the other invertebrate taxa, demersal fish, and algae. The depth and bottom temperature recordings describe the physical condition during the survey. Depth and bottom temperature were criteria used to summarize the biomass listing of the major taxonomic groups. A description of sediments and their distribution was made from samples obtained with a van Veen grab, piston cores (Alpine corer), and dredges. The core samples were analyzed for heavy metal content.

Garbary, David J., and Lana Beth Barkhouse (1987). Blidingia ramifera stat. nov. (Chlorophyta): a new marine alga for eastern North America. Nordic Journal of Botany 7: 359-363.

Abstract: Blidingia minima var. ramifera is reported for the first time in eastern North America. It occurs in the Gulf of St. Lawrence, Nova Scotia and in Maine. In the estuary of the West and Rights Rivers (Antigonish Harbour, Nova Scotia) it is the most common intertidal alga and during its maximum growth period (June-August) covers 75-90% of the intertidal zone for several km of shoreline at the mouth of the Rights River. In culture, spore germination and early development were typical of the taxon as described from Europe. The taxon is raised to specific status as Blidingia ramifera stat. nov. Blidingia subsalsa is confirmed from New England based on observations of spore germination in plants from Maine and Connecticut.

Garbary, David. (1988). Interoceanic Hybridization in Fully Corticated Ceramium Isolates (Rhodophyta) from Nova Scotia and Washington. The Korean Journal of Phycology 3, No. 2: 89-93.

Abstract: Four independent isolates of a fully corticated Ceramium (cf. Ceranium rubrum ) from eastern and western North America completed their life histories in unialgal culture with a Polysiphonia -type life history. Two isolates from Washington State (Fidalgo Island and San Juan Island) were partially interfertile, while two isolates from Nova Scotia did not form hybrids. One Washington isolate (Fidalgo I.) and one Nova Scotia isolate (Pomquet Hbr.) formed successful hybrids. Reciprocal crosses between these isolates produced viable carpospores, and the hybrid was successfully cultured through three complete Polysiphonia -type life histories. The first generation of gametophytes also produced viable backcrosses with parental material. These results confirm the conspecificity of a Ceramium species from the Pacific and Atlantic Oceans and provide the first example of interoceanic hybridization in red algae.

Garbary, David J. (1997). Codium fragile ssp. tomentosoides (Chlorophyta) Invades the Gulf of St. Lawrence, Atlantic Canada. Botanica Marina 40: 537-540.

Abstract: Codium fragile (Suhr) Hariot ssp. tomentosoides (van Goor) Silva is reported for the first time from the Gulf of St. Lawrence in Nova Scotia based on collections made in August 1996. Three drift thalli were collected initially from the southeast corner of Doctor Island, Caribou Harbour. Later an extensive subtidal population extending over 0.5 kilometers squared was located in the adjacent subtidal zone (1m) associated with a former oyster lease. The habitat was a soft bottom embayment dominated by Zostera marina, and the Codium fragile was found as scattered individuals in scours in the Z. marina bed. The potential ecological impact of C. fragile on community structure and human activities in the southern Gulf of St. Lawrence is discussed.

Hargrave, B. T., G. C. Harding, et al. (1985). Dynamics of the pelagic food web in St. Georges Bay, southern Gulf of St. Lawrence. Marine Ecology Progress Series 20: 221-240.

Abstract: Phytoplankton standing stock and production increased between June and October in St. Georges Bay, Nova Scotia, Canada. Inorganic nitrogen is believed to be the limiting nutrient in the Bay and it is deduced that in situ regeneration must have satisfied most of the summer demand by primary producers. The proportion of organic matter sedimented, relative to that produced by phytoplankton during this time, depended upon the degree of water stratification. Sedimentation of organic carbon and nitrogen amounted to between 9 and 14% of that assimilated by phytoplankton during maximum stratification in August, implying that ~ 90% of the organic matter produced was recycled above the thermocline. Although copepod biomass decreased, production increased in late June and remained high throughout the summer because of rapid development at high summer temperatures. The production of mackerel and lobster larvae, estimated from studies in other years, was greatest from the late July to mid-August. Thus, maximum consumption of the products of phytoplankton production in the water column above the thermocline and minimum transfer of particulate organic matter to the benthos coincided with maximum growth and production rates of copepods and their predators. Calculations of potential food consumption by larval and adult fish, estimated from biomass, showed that standing stocks of planktonic prey organisms could not support the biomass of fish present. The predictable occurrence of warmer waters with rapid production of prey organisms and the restricted exchange with offshore waters makes St. Georges Bay a successful nursery ground for pelagic spawners.

Note: This paper makes significant points concerning the relationship between several "interdependent factors", which are important for the survival of these species in this ecosystem. "Rapid summer heating and stratification of the shallow waters of the Bay increase the metabolic rates of all organisms and thus contribute to the observed rapid recycling of material produced above the thermocline." It should also be noted that "the high summer growth rates of larval fish and decapods in St. Georges Bay are dependent on the rapid cycling of all components of the ecosystem and are directly dependent on the rapid turnover of small zooplankters which are optimal food for fast growing larvae."

Hargrave, B. T. and G. A. Phillips (1986). Dynamics of the benthic food web in St. Georges Bay, southern Gulf of St. Lawrence. Marine Ecology Progress Series 31: 277-294.

Abstract: In situ rates of oxygen uptake, carbon dioxide and inorganic nitrogen release from sediments at 34m depth in St. Georges Bay, Nova Scotia (Canada) increased as temperature of bottom water increased between April and November. Rates of gas and nutrient exchange were linearly related to temperature and regressions were used to estimate daily rates of exchange between sediment and overlying water. Sedimentation of particulate organic carbon from the euphotic zone at depths above bottom which reduced collection of resuspended material was slightly less than carbon released by benthic aerobic respiration between April and November. Anaerobic microbial respiration corrected for aerobic oxygen uptake accounted for approximately 50% of total carbon dioxide release. Nitrogen sedimentation from the euphotic zone exceeded regeneration of inorganic nitrogenous nutrients from sediments during periods of weak stratification but a balance existed when the water column was stratified. Total inorganic nitrogen release including N2 produced by denitrification was measured but mineralization could have supplied approximately 20% of phytoplankton requirements if nutrients released at the sediment were distributed homogeneously to the euphotic zone. Estimates of production by benthic macrofauna, calculated from biomass and assumed annual turnover ratios, equalled from 10 to 30% of average particulate organic carbon sedimentation at 22m for stratified and unstratified periods. Demersal fish production by a similar calculation amounted to from 1 to 7% of estimated production of macrobenthos.

Note: This paper discusses changes in the rates of particulate organic supply over a three year period in St. Georges Bay. The rates are examined through: aerobic and anaerobic respiration for comparison with carbon dioxide release, temperature and the thermocline, phytoplankton production, as well as organic carbon and nitrogen sedimentation.

MacKinnon, Mark (1997). Short-term Environmental Perturbations and Phytoplankton Dynamics in Pomquet Harbour, Nova Scotia. BSc with Honours, St. Francis Xavier University, Antigonish, Nova Scotia. 38pp.

Abstract: Abundances and compostition of species of the phytoplanktonic communities of Pomquet Harbour and St. Georges Bay, Nova Scotia were studied from September 1996 to January 1997. Seven samples were taken at roughly fortnightly intervals from four sites. There was no clear difference between the samples from the bay and the harbour, although at each sampling time the harbour samples were more similar to each other than to the bay. The primary species in the study were Skeletonima costatum, Legtocylindrus danicus, Chaetoceros spp., Navicula spp., Pleurosigma angulatum, and Melosira spp. Grammatophora marina was only present in the bay, whereas Thalassiosira gravida, Chaetoceros danicus, Striatella unipunctata, Licmophora lyngbyei, Achnanthes longipes, Caloneis sp., Cocconeis scutellum, Pinnularia ambigua, Gyrosigma sp., Amphiprora alata, Nitzschia seriata, Surirella sp., and Ceratium longipes were only present in the harbour. Changes in community structure are related to environmental changes in temperature and light. Sixty-eight taxa were observed and thrity-one quantified, the list consisting of many diatom species and few dinoflagellates. Species composition in the harbour resembled Malpeque Bay, Prince Edward Island, and abundances ranging from zero to 10² - 10³ cells/mL were observed. Cluster analysis of species lists for the 27 samples revealed no evidence for migration of communities between sites as the means of succession, but showed that the sampling site located on the coast outside the harbour was the most dissimilar of the four.

McLachlan, Jack L. (1994). TETREUTREPTIA POMQUETENIS GEN. ET SP. NOV. (EUGLENOPHYCEAE): A QUADRIFLAGELLATE, PHOTOTROPHIC MARINE EUGLENOID. Journal of Phycology 30: 538-544.

Abstract: A new englenoid genus and species, Tetreutreptia pomquetensis, is described from winter water of Maritime Canada. This phototrophic species is characterized by four emergent heterodynamic flagella, two about the length of the cell and two less than one-half this length. Tetreutreptia pomquetensis has features in common with species of Eutreptiella while it differs in several respects from any of the described species of that genus. It could be assigned to the order Eutreptiales or Euglenamorphales sensu Leedale or the order Euglenales sensu Farmer. This new alga has a narrow range of temperature tolerance; it grows best from 0 degrees to 7 degrees Celsius and dies at temperatures above 10 degrees Celsius. The optimum salinity for growth was near full-strength seawater. Growth conditions for the alga define the conditions whence this species was isolated.

Note: This species was discovered in Pomquet Harbour, Nova Scotia in January 1990.

Novaczek, I., and J. McLachlan (1989). Correlation of Temperature and Daylength Response of Sphaerotrichia divaricata (Phaeophyta, Chordariales) with Field Phenology in Nova Scotia and Distribution in Eastern North Amercia. British Phycological Journal 22: 215-219.

Abstract: Sphaerotrichia divaricata from the southern Gulf of St. Lawrence, Canada has been studied in the field and in laboratory culture. Juvenile macrothalli occurred on eelgrass (Zostera marina ) in early summer when water temperature was rising from 5 degrees to 20 degrees Celsius. Macrothalli bore unilocular sporangia from August to late November. In culture, unispores developed into haploid microthalli that tolerated -1 degrees to 28 degrees Celsius and were asexual under most conditions, but functioned as dioecious gametophytes at 0 degrees to 15 degrees Celsius in long days. Microthalli in the field presumably replicated themselves asexually during summer months when water temperature exceeded 15 degrees. Juvenile macrothalli were again found in early October, after initiation in Septeber when water temperature dropped below 15 degrees Celsius and daylength still exceeded 12h. Fully formed macrothalli tolerated temperatures of 5 to 24 degrees Celsius, but macrothallus protonemata also survived 0 degrees Celsius. The species extends along the Atlantic coast of North America from northern Labrador to New Jersey. The northern boundary marks a summer temperature limit for maturation of macrothalli; the southern boundary marks the limit of coincidence of low temperatures and long daylength.

Novaczek, I., C.J. Bird, and J. McLachlan. (1989). Phenology and temperature of the red algae Chondria baileyana, Lomentaria baileyana, Griffithsia globifera, and Dasya baillouviana in Nova Scotia. Canadian Journal of Botany 65: 57-62.

Abstract: The warm-termperate species Chondria baileyana, Lomentaria baileyana, Griffithsia globifera, and Dasya baillouviana are restricted, north of Cape Cod on the eastern American coast, to embayments and estuaries. The northern limit of distribution is the southern Gulf of St. Lawrence. In culture, isolates of these species from Nova Scotia survived 28 to 34 degrees Celsius. In the field all reproduced during the period of maximum temperature, and in G. globifera and C. baileyana the progeny also reproduced. Some of the progeny of D. baillouviana developed as cold- and heat-resistant pads that survived the winter, whereas the other three species died back to perennating holdfast structures. Lomentaria baileyana was the least successful of the group, being unable to form resistant holdfast pads in midsummer temperatures and having the most limited reproductive period and smallest population size.