Recovery of an Intertidal Assemblage Following a Rare Occurrence of Scouring by Sea Ice in Nova Scotia, Canada

Previous observations in the St Lawrence Estuary (eastern Canada) suggested that larvae of intertidal barnacles (Semibalanus balanoides) would settle almost exclusively inside crevices on shores that are scoured by sea ice every winter. It was suggested that the strong ice scour in winter on that coast (which removes organisms outside of crevices) would select for such a larval behaviour. We tested the generality of this pattern by sampling other ice-scoured shores within the Gulf of St Lawrence system. In particular, we surveyed a shore in Nova Scotia where exposed habitats (subjected to strong ice scour in winter) are interspersed with sheltered habitats (which suffer milder ice scour). Such a topographical complexity might allow for the coastal larval pool to contain a proportion of larvae that have no particular settlement preference for crevices, as selective pressures for such a behaviour would be minimal in ice-sheltered habitats. Consistently with this notion, barnacle recruits (which appear after the winter ice melts) occurred abundantly both inside and outside of crevices across the shore in the spring seasons of 2005 and 2006. Average recruit density on rocky surfaces ranged between 337 and 588 recruits dm−2, depending on the habitat. It is therefore possible that barnacle recruitment patterns on ice-scoured shores may be affected indirectly by the structural complexity of the coast.

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Visual record of intertidal disturbance caused by drift ice in the spring on the Atlantic coast of Nova Scotia

F1000Research ◽

10.12688/f1000research.4146.1 ◽

2014 ◽

Vol 3 ◽

pp. 112 ◽

Cited By ~ 4

Author(s):

Willy Petzold ◽

Maike T. Willers ◽

Ricardo A. Scrosati

Keyword(s):

Nova Scotia ◽

Sea Ice ◽

Atlantic Coast ◽

Early Spring ◽

Rocky Intertidal ◽

Physical Disturbance ◽

Biological Communities ◽

Ice Conditions ◽

Ice Floes ◽

Visual Record

In the early spring of 2014, an unusually large amount of sea ice drifted from the Gulf of St. Lawrence, where it had been produced, towards the open Atlantic Ocean through the Cabot Strait, between Nova Scotia and Newfoundland, Canada. In early April, significant amounts of drift ice reached the Atlantic coast of mainland Nova Scotia. The ice floes persisted in those coastal waters for up to 16 days, depending on the location. During that time, the ice fragments caused extensive physical disturbance in rocky intertidal communities, removing high quantities of seaweeds and invertebrates. For example, at a location where the ice stayed for 9 days, the loss of macroalgal and invertebrate biomass was almost total. At a location where the ice stayed for 4 days, losses were lower, albeit still high overall. Such a magnitude of disturbance is not common on this coast, as sea ice had not reached the surveyed locations in the previous 4–5 years. We suggest that the frequency of ice scour events may help to predict intertidal community structure. This notion could be tested through multiannual surveys of ice conditions and biological communities along the Atlantic coast of Nova Scotia.

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In search of a climate change signal in Nova Scotia: the Alexander Mackay data, 1901-1923

Proceedings of the Nova Scotian Institute of Science (NSIS) ◽

10.15273/pnsis.v50i1.8876 ◽

2019 ◽

Vol 50 (1) ◽

pp. 131

Author(s):

Madison Culbertson-Paoli ◽

Laura Farro ◽

Andrew Long ◽

Steven Wilkinson

Keyword(s):

Public Schools ◽

Nova Scotia ◽

Sea Ice ◽

Climate Change Signal ◽

Appearance Time ◽

Scotia Sea ◽

Phenological Data ◽

Citizen Science Project ◽

Nova Scotian ◽

Good Agreement

Our objective in this work is to model First Appearance Time (FAT) of flowering in five species of plants in Nova Scotia, Canada, as a function of climatic variables (such as temperatures) and geographical factors (such as latitude). Dr. Alexander H. MacKay was the superintendent of public schools in Nova Scotia from 1891-1926. Beginning in 1896 MacKay instructed all the school teachers of Nova Scotia to have their students collect data on the first appearances of numerous plants, animals, and seasonal events, and then summarized the data himself. The summaries of the phenological data collected in this massive citizen science project were then published in the Proceedings of the Nova Scotian Institute of Science in a consistent fashion over the period 1901-1923. We analyze five species from the summary MacKay data for Nova Scotia, producing a model for First Appearance Time of flowering for each, as a function of latitude, longitude, mean monthly temperatures for many months, and sea ice off the coast of Newfoundland in winter months. Our model produces good agreement between predicted FATs and those FATs we find in the literature.Key Words: 1901-1923, Alexander MacKay, First Appearance Time (FAT), flowering, latitude, longitude, mean monthly temperatures, Nova Scotia, sea ice.

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