Biology: Recent submissions
Now showing items 61-80 of 228
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Behaviour of sea urchin Strongylocentrotus droebachiensis grazing fronts: food-mediated aggregation and density-dependent facilitation
(2007)The occurrence of destructive grazing fronts is a common phenomenon in sea urchins, but mechanisms governing front formation and dynamics remain poorly understood. We experimentally examined the effect of kelp biomass ... -
Survival analysis of tethered juvenile sea scallops Placopecten magellanicus in field experiments: Effects of predators, scallop size and density, site and season
(1994)The impact of predation on survival of juvenile sea scallops Placopecten magellanicus has important implications for the population dynamics and aquaculture of this species. In field experiments using tethered juvenile ... -
Modelling phase shifts in a rocky subtidal ecosystem
(Inter-Research, Nordbuente 23 Oldendorf/Luhe 21385 Germany, [mailto:ir@int-res.com], [URL:http://www.int-res.com/], 2008-03)The rocky subtidal ecosystem of the Atlantic coast of Nova Scotia is characterised by 2 community states, kelp beds and urchin barrens that alternate on a decadal time scale. While the shift from barrens to a kelp bed ... -
Spatial dynamics, ecological thresholds and phase shifts: modelling grazer aggregation and gap formation in kelp beds
(2010)On the Atlantic coast of Nova Scotia, transitions between alternative states of the subtidal ecosystem, kelp beds and sea urchin barrens, occur on a decadal scale. To explore the process of urchin aggregation within kelp ... -
Modelling phase shifts in a rocky subtidal ecosystem
(2009)The rocky subtidal ecosystem of the Atlantic coast of Nova Scotia is characterised by 2 community states, kelp beds and urchin barrens that alternate on a decadal time scale. While the shift from barrens to a kelp bed ... -
Fatty acids as dietary tracers in benthic food webs
(Inter-Research, Nordbuente 23 Oldendorf/Luhe 21385 Germany, 2011)Fatty acid (FA) analysis is a well-established tool for studying trophic interactions in marine habitats. However, its application to benthic food webs poses 2 particular challenges. First, unlike pelagic zooplankton, ... -
Fatty acid profiles in the gonads of the sea urchin Strongylocentrotus droebachiensis on natural algal diets
(2008)We examined fatty acid (FA) compositions of gonads of the green sea urchin Strongylocentrotus droebachiensis collected from a grazing aggregation (front) at the edge of a kelp bed and from barrens dominated by coralline ... -
Procedural effects of prey tethering experiments: Predation of juvenile scallops by crabs and sea stars
(1994)This study examines the effects of an experimental tethering procedure often used in field predation experiments. In laboratory experiments, juvenile sea scallops Placopecten magellanicus, either free or tethered, were ... -
Invasion-mediated shifts in the macrobenthic assemblage of a rocky subtidal ecosystem
(2011)We tracked changes in community composition that occurred with state shifts in the rocky subtidal ecosystem in Nova Scotia, Canada, from 1992 to 2008. At the beginning of our study, a dense aggregation of sea urchins was ... -
Spatial and temporal variability of patterns of colonization by mussels (Mytilus trossulus, M-edulis) on a wave-exposed rocky shore
(1998)Colonization rates of mussels (Mytilus trossulus and M. edulis) were measured on natural substrata in tidepools and on emergent rock in recently ice-scoured and non-scoured regions of a rocky shore near Halifax, Nova ... -
Non-Occurrence of Free-Living Paramoeba-Invadens in Water and Sediments of Halifax Harbour Nova Scotia Canada
(1989)Seawater and sediment samples from various sites in or near Halifax Harbour were cultured for Paramoeba as were tissues of the natural sea urchin host Stronglyocentrotus droebachiensis sampled from Halifax Harbour. An ... -
Structure and Dynamics of Epifaunal Assemblages on Intertidal Macroalgae Ascophyllum-Nodosum and Fucus-Vesiculosus in Nova-Scotia, Canada
(1987-05)No abstract available. -
Fatty acids tracers for native and invasive macroalgae in an experimental food web
(2009)We assessed the potential of fatty acid (FA) markers for tracing primary production from an invasive green alga (Codium fragile ssp. fragile) and a native kelp (Saccharina longicruris) through 2 trophic levels in an ... -
Physical and biological factors influencing mussel (Mytilus trossulus, M. edulis) settlement on a wave-exposed rocky shore
(1996)Settlement rates of mussels Mytilus trossulus and M. edulis on artificial collectors (aquarium filter wool) and natural substrata were measured in tidepools and on emergent rock in recently ice-scoured and non-scoured ... -
Structure and dynamics of mussel patches in tidepools on a rocky shore in Nova Scotia, Canada
(1995)The distribution, size structure, and dynamics of mussel (Mytilus trossulus, M. edulis) patches in tidepools were studied on an exposed rocky shore near Halifax, Nova Scotia, Canada. The mussel patches were dynamic, ... -
Temporal and spatial variability in settlement and recruitment of echinoderms in kelp beds and barrens in Nova Scotia
(2000-10)Settlement and recruitment of echinoderms were measured in 2 adjacent habitats: a kelp bed (Laminaria longicruris) and an echinoid (Strongylocentrotus droebachiensis)-dominated barren ground at each of 2 sites in the ... -
Role of early post-settlement mortality in recruitment of benthic marine invertebrates
(1997-08)Newly settled invertebrates usually are subject to high rates of mortality (Type III survivorship). Therefore, knowledge of early post-settlement events is critical in determining if and when patterns of abundance and ... -
Predicting wave dislodgment of mussels: variation in attachment strength with body size, habitat, and season
(2001)Breaking waves impose large hydrodynamic forces which may dislodge mussels and other organisms living on exposed rocky shores. We examined the effect of variation in attachment strength with size, habitat and season on ... -
Killer storms: North Atlantic hurricanes and disease outbreaks in sea urchins
(2010-11)An increase in the incidence of disease in various marine organisms over the past few decades has been linked to ocean climate change. In Nova Scotia, Canada, mass mortalities of sea urchins, due to an amoebic disease, ... -
Role of grazing by sea urchins Strongylocentrotus droebachiensis in regulating the invasive alga Codium fragile ssp tomentosoides in Nova Scotia
(2005)To assess the potential of herbivory in regulating the invasive green alga Codium fragile ssp. tomentosoides, field and laboratory experiments were conducted with the green sea urchin Strongylocentrotus droebachiensis ...