800 Atlantic Coast
The Atlantic Coast Region is divided into nine Districts based upon major geomorphological characteristics:
810 Basalt Peninsula
Districts 830, 840, and 850 are further divided into Units based upon geomorphological, soil, and vegetation characteristics.
The Atlantic Coast Region is much influenced by the adjacent Offshore/Continental Shelf (Region 900). There is a transition zone where the marine and terrestrial conditions interact, and it is sometimes difficult to make a distinction between coastal and offshore waters. In general, Region 800 extends to the low tide mark, and marine conditions are described in Region 900. However, in some bays, such as St. Margarets and Mahone bays (District 460), the marine characteristics are more typically coastal and the District encompasses subtidal waters.
The Western Shore, South Shore, and Eastern Shore (Districts 820, 830, and 840) are dominated by the old and generally very hard rocks of the Meguma Group. These are interfolded slates and greywackes, with local outcroppings of metamorphosed volcanic ash and lava (Yarmouth area). Areas of very resistant granite (District 850) also occur. In contrast, Chedabucto Bay has been eroded from weakly metamorphosed Carboniferous sandstones (District 860). Southeastern Cape Breton (District 870) is underlain by metamorphosed Precambrian volcanic ash deposits, sandstone, and granite.
At the entrance to the Bay of Fundy, Digby Neck (District 810) is a low-lying basalt ridge. St. Paul Island (District 880) consists of very ancient Precambrian rocks similar to those found in the Cape Breton massif.
The coastal bedrock is low-lying and exhibits low relief. Elevations rarely exceed 100 m, except on the granite promontories and knolls at Pennant Barrens (Unit 851) and Canso Barrens (Unit 852), where the maximum elevation is 250 m.
The shape of the coastline is also strongly influenced by faults, especially along the Eastern Shore and the southern boundary of Chedabucto Bay. Many of the long inlets in Guysborough County have formed along fault lines. The straight shore west of Cape Canso marks the position of the Chedabucto Fault. The smooth eastern shoreline of the Louisbourg lowlands (and Gabarus Bay) may also be fault-controlled. The orientation of St. Marys Bay, North Mountain, and the Parrsboro shore also owe much to fault movements within the Bay of Fundy area.
Along the coast the amount of sediment available for redistribution depends largely upon the nature of the glacial deposits. Areas with drumlin headlands and islands tend to have adequate sediment supply derived from coastal erosion. Another very limited source of coastal sediment, quartz sand, is washed from the surface of coastal granite bodies by subaerial erosion. A more important source of coastal sediment is silt and sand that was carried landward from glacial deposits on the Scotian Shelf by the sea as it rose during the post-glacial period. Many of the present sand beaches owe their origins to material driven landward in this manner.
The median extent of sea ice just reaches the eastern limit of this region. In heavier-than-average ice years, ice fields may extend as far southwest as Halifax County.
The background features of the ocean climate are controlled by the southwest-flowing Nova Scotia Current, which is relatively low in salinity; superimposed upon this are meteorological events which can bring large runoffs of fresh water or upwellings of saltier deeper waters. In general, the Region is a cool-water coast. In summer the coldest temperatures are found around Cape Sable and in the Bay of Fundy, as a result of a strong mixing of surface waters by tidal currents.
The ocean is the dominant influence on the Region's climate. The main features are moderated seasonal and daily temperatures, high precipitation and humidity, strong winds, fog, and salt spray.
The winters are comparatively mild, and the summers are short and cool. The mean annual temperature range is 15-20°C and is least in the southwest, increasing towards Cape Breton. This can be contrasted to a mean annual temperature range of 20-25°C throughout the rest of the province. Along the coast, spring starts early but is long and cool. Mean daily temperatures rise above the freezing point about the second week of March in the south, and about two to three weeks later along the Eastern Shore and in Cape Breton. Because of frequent fogs, and the cooling influence of ocean waters, the mean daily temperature in July stays below 15°C near the coast, increasing somewhat inland. Mean daily freezing temperatures return to northern inland areas before the end of November, but in the Atlantic Coast Region this does not usually happen until after the second week in December, or even as late as the end of December in the southwest. Mean daily January temperatures stay above -5°C and, in some areas, remain above 0°C.
Like most of the province, the Atlantic Coast Region receives fairly high total precipitation, generally between 1200 and 1400 mm, but between 1400 and 1600 mm in Queens and Lunenburg counties and in the northern half of Halifax County. Only about 15 per cent falls as snow because of the mild winter temperatures. Most of the Region receives less than 200 cm of snow annually, and Guysborough County and Cape Breton receive less than 150 cm. The snow-cover season starts late and finishes early, ranging from less than 100 days near Cape Sable to more than 130 days in Cape Breton. Snow accumulations are usually low.
Fog and high humidities are common along the Atlantic coast. Summer and fall are the main seasons for fog, when warm, moist air moving in from the south comes into contact with cool Atlantic coastal waters. On average, fog occurs 15-25 per cent of the year. The southwestern section of the coast is the foggiest, with Yarmouth registering an average of 120 days in which fog occurs.
The main features of the bioclimate of the Atlantic coastal forest are the long frost-free period and long growing period, combined with cool summer temperatures, low evapotranspiration rates, and exposure to wind.
In the southwestern part of the Region, White Spruce, Black Spruce, and Balsam Fir are accompanied by White Birch and Red Maple (H6.3). The reappearance of White Pine and Red Oak inland usually indicates less rigorous climatic conditions and can therefore mark an approximate inland boundary. In the northern part of the Region, where the winters are colder, White Spruce continues to be prominent along the shore but is less abundant away from the water. Dense stands of Balsam Fir, Black Spruce, and White Spruce are characteristic, along with a virtual absence of Red Spruce, White Pine, and most hardwood species. Jack Pine sometimes occurs on fire barrens, and larch is common on wetter soils, particularly in Cape Breton. Excessive stand density may be another factor besides wind exposure that limits tree growth in this part of the Region. Throughout the Region, barrens or semi-barrens are common, supporting mostly low, ericaceous (heath) vegetation. Sphagnum bogs are also common in depressions.
C.D. Howe's description of this "black" forest written in 1912 is still true today: "The numerous peninsulas formed by the long re-entrant bays and harbours are covered with an inferior black spruce-fir forest and exhibit abundant bogs. The softer places in the rock have been worn into little hollows and pockets, sometimes only a few feet and usually not many rods apart. These fill with water which cannot drain away freely because of the massive quartzite beneath. The loss by evaporation is replaced by frequent rains, but it is also very much retarded by the natural humidity of the air. The result is a sour soil composed of raw humus, and hence the stunted forest. The trees are about ten to fifteen feet high, and frequently not more than three or four feet high in the more boggy situations. A section of one of these trees, three-eighths of an inch in diameter, when placed under a compound microscope revealed 47 annual rings. On the drier portions where a little real soil is present, one finds sapling thickets and dense polewood stands of fir. Along the streams of normal rapidity the stand is mostly second growth yellow birch and red maple."
The coastal strip from Halifax around to Meteghan and inland for 10-20 km has the least persistent winter snow cover of any area in the province. This creates severe microclimatic stress for small mammals during cold snaps, and in the case of the Deer Mouse this stress is at the limits of tolerance. Almost certainly because of this, deer mice are very rare there and usually absent from most areas in this zone at most times; White-footed Mouse is the dominant species of Peromyscus in the District.
Marine fauna is mostly cold-water boreal in character but is not homogenous along the coast. Sheltered inlets and pockets of warmer water support many species with a more southerly distribution. Productivity is high along the edge of the Scotian Shelf, and marine mammals are quite numerous. The Atlantic coast is often visited by unusual bird and marine species carried by winds and currents from other parts of the Atlantic Ocean.
The islands along the Atlantic coast were used as fishing stations and for sheep grazing, and small seasonal fishing communities and flocks of sheep remain on some of them today.
Drumlins found along the Atlantic coast have been cleared and used as productive farmlands. Forestry exploitation occurs at various coastal sites and this wood, along with that from the interior, supplies newsprint and hardboard mills at Brooklyn, East River, and Point Tupper. In the nineteenth century, many Nova Scotian ports on the Atlantic coast shipped immense volumes of timber to Britain. The viability of several of Nova Scotia's resource industries (pulp and paper products, gypsum, aggregates) is closely tied to the accessibility of marine transportation. Deepwater harbours such as Halifax and Port Hawkesbury are an important resource and are among the largest ice-free deepwater ports in the world. Today, as in the past, the shipping industry and transport by water are very important to the provincial economy and ports along the Atlantic coast. Most of the coastline has rocky, shallow, and acidic soils and offers low agricultural capability except for subsistence gardening.