Bay of Fundy ecosystem

• Category: Marine and Oceanic Biomes.
• Geographic Location: North America.
• Summary: With the greatest tidal range of any place on earth, the Bay of Fundy is filled with rich marine and terrestrial life, as well as a robust variety of coastal plants.

Aside from the striking beauty of its imposing rocky shores, one of the first things a visitor notices about the Bay of Fundy, on Canada's Atlantic Coast between New Brunswick and Nova Scotia, is the incredible changes brought on by its tides. At high tide, a boat may be even with the dock so that a passerby can easily step onto the deck. At low tide, the boat may be resting on the mud below and that same passerby may be able to attach a flag to the tip of its mast.

With a tidal range of up to 50 feet (15 meters), the Bay of Fundy, which extends northeast for nearly 200 miles (320 kilometers) from its mouth in the Gulf of Maine, has the greatest tidal range of any place on Earth. The tidal bore, or incoming tide, can sound something like an oncoming train. In fact, the volume of water entering the bay at flood time is similar to that flowing through the Gulf Stream.

The extreme differences in height between high and low tides and the violence with which the waters ebbs and flows here create numerous challenges for organisms living in the Bay of Fundy's intertidal zone. The bay's intertidal zone—the area alternatively flooded and exposed by the semi-diurnal (twice-daily) tides—is a mosaic of sandy or rocky beach, mudflat, and salt marsh. On steeply sloping shorelines, low tide reveals a damp zone as high as a two- or three-story building. On gently sloping shorelines, one may (at one's peril) wander thousands of yards out over exposed mud flats before reaching the waves.

The Bay of Fundy's climate supports organisms characteristic of cooler seas. Classified as a cold mid-latitude climate with warm summers and no dry season, the area has a mean monthly temperature of 17.4 degrees F (minus 8.1 degrees C) in January to 62.8 degrees F (17.1 degrees C) in July at Saint John, New Brunswick, a port city about midway up the bay's western coast. Monthly precipitation ranges from 3.5 inches (89.6 millimeters) in August to 5.5 inches (139.4 millimeters) in January. The mean water temperature is 32 degrees F (0 degrees C) in winter and 54 degrees F (12 degrees C) in summer.

Terrestrial and Sea Life

The shores of the bay, in the Kejimkujik National Park in southwestern Nova Scotia, are home to hundreds of species of vascular plants, including 23 fern, 15 orchid, and 37 aquatic plant species. On Brier Island, so named for the Brier rose that grows freely across its undulating surface, such rare plants as bluebead lily, pink ladyslipper, fireweed, yellow iris, shrubby cinquefoil, pitcher plant, and the endangered eastern mountain avens are found. A large portion of the island is a nature preserve administered by the Nature Conservancy of Canada.

In terms of the proportion of surface cover, bare rock and tar lichen (Verrucaria marra) dominate the region of the high tide line around the bay. Other species reach their highest-percent cover at the high tide line; these include a green alga (Ulothrix flacca), a red alga (Hildenbrandia rubra), and an acorn barnacle (Semibalanus balanoides). The occurrence of brown alga (Fucus spiralis) increases with depth until the middle of the intertidal zone, where it dominates.

Knotted wrack (Ascophyllum nodosum) is the leading species in terms of surface cover from about 30 percent of the tidal range above mean low water to about 80 percent of the range. Bladder wrack (Fucus vesiculosus) has the next-highest cover in the middle of the zone. A red alga, wrack siphon weed (Polysiphonia lanosa), reaches its own highest percentage cover in the middle portion of the zone. A hydrozoan, Dynamena pumila; a bryozoan, Flustrellidra hispida; and a polychaete, Fabricia sabella, are often associated with the knotted wrack.

Several species increase in abundance with increasing depth. These include brown alga, such as bladderlocks (Alaria esculenta) and Fucus evanescens; a golden brown alga, Ectocarpus siliculosus; a green alga, Acrosiphonia arcta; and red algae including carrageen (Mastocarpus stellatus and Chrondrus crispus), dulse (Palmaria palmata), laverbread (Porphyra umbilicalis), Devaleraea ramentacea, Rhodochorton purpureum, and several crustose species such as Petrocelis middendorffi. Tortoise-shell limpets (Testudinalia testudinalis) are frequently associated with red algae.

Marine animal life in the Bay of Fundy biome is rich with species, including a range of sharks, including spiny dogfish (Squalus acanthias), the most common shark in the bay; basking shark (Cetorhinus maximus), the second-largest shark; great white shark (Carcharodon carcharias), usually found between April and November; thresher (Alopias vulpinus); and porbeagle (Lamna nasus). The sharks feast on squid, herring, mackerel, small cod, hake, and cusk. They all share the waters with porpoises, sea turtles, and such whales as the right and humpback.

Smaller marine species include the rough periwinkle (Littorina saxatilis), the common flat periwinkle (L. obtusata), and common periwinkle (L. littorea), all grazers. Green sea urchins (Strongylocentrotus droebachiensis) are abundant at lower levels of the intertidal zone. The dog whelk (Nucella lapillus), a predatory snail, prowls the center of the zone.

Salt marsh is most extensive at two locations in the head of the Bay of Fundy: New Brunswick's Cumberland Basin and Nova Scotia's Minas Basin. The marshes can be divided into two basic types: high marsh, which is infrequently inundated; and low marsh, which is flooded frequently. Cordgrasses (Spartina spp.) dominate both marsh types.

Other high marsh species include quackgrass (Agropyron repens), saltmeadow rush (Juncus gerardi), goose tongue (Plantago maritima), American alkaligrass (Puccinellia americana), and seaside alkaligrass (P. maritima), and both smooth and prairie (Spartina pectinata) cordgrass. Other low marsh species include American alkaligrass, slender grasswort (Salicornia maritima), and herbaceous seepweed (Suaeda maritima).

Along the shores, sandpipers and plovers, white-tailed deer, and moose can be found. Patrolling the skies are bald eagles, ospreys, and peregrine falcons.

Environmental Challenges

As the earth warms, the impact on terrestrial and aquatic life in the Bay of Fundy becomes vulnerable to mutations. Long-term changes in average water temperature could affect the entire life cycle of the fish swimming in and out of the area. Their distribution range could shrink or expand, depending on a species's temperature tolerance and preference. In the 1960s, when water temperatures south of Newfoundland fell slightly, capelin, a cold water fish, moved south toward the Bay of Fundy—and then moved back again in the 1970s when the ocean warmed once more.

Cod, halibut, and plaice altered their distributions in a similar way. It also appears that changing ocean temperatures might cause some fish to alter their migration routes, departure and arrival times, or even their final destinations. Temperature changes can influence the reproduction cycle of fish, the number of eggs laid, incubation time, survival of their young, growth and feeding rates, and the time it takes for them to reach maturity. For example, cod grow faster in warmer water.

The impact of climate change on salmon and shellfish in the Bay of Fundy biome is likely to be both beneficial and detrimental to the species. The salmon, like the cod, grow faster and bigger in warm waters and could reduce the costly fish kills that occasionally happen when the water temperature falls too low in the winter. The benefits, however, might be more than offset by a greater incidence of toxic blooms, disease, or parasites. Significant temperature change in coastal waters might alter the types of fish and shellfish that can be successfully farmed in the region. According to a 2022 report, water temperatures in the bay have been rising for the past decade and are predicted to continue to warm.

Weather changes due to climate change impact both the number and severity of storms along the coastal regions of the Bay of Fundy. As a result, storm surges could be more detrimental to the land, biota, and people of the bay, with the potential to devastate fishing, farming, and forestry industries in its environs.

Bibliography

Gordon, Donald C. Jr., Peter J. Cranford, and Con Desplanque. “Observations on the Ecological Importance of Salt Marshes in the Cumberland Basin, a Macrotidal Estuary in the Bay of Fundy.” Estuarine, and Shelf Science 20, no. 2 (1985).

Leslie, Scott. Bay of Fundy: A Natural Portrait. Toronto: Key Porter Books, 2007.

Lyons, Kristyn. “Warming Waters Will Bring Big Changes to Bay of Fundy.” Conservation Council of New Brunswick, 3 Feb. 2022, www.conservationcouncil.ca/warming-waters-will-bring-big-changes-to-bay-of-fundy/#:~:text=The%20Bay%20of%20Fundy%20is,the%20Bay%20of%20Fundy's%20ecosystem. Accessed 25 Dec. 2024.

Mathieson, A. C., C. A. Penniman, and L. G. Harris. “Northwest Atlantic Rocky Shore Ecology.” In A. C. Mathieson and P. H. Nienhuis, eds. Intertidal and Littoral Ecosystems. Amsterdam: Elsevier, 1991.

Sherren, Kate. et.al. "Understanding Multifunctional Bay of Fundy Dykelands and Tidal Wetlands Using Ecosystem Services--A Baseline." Facets, 26 Aug. 2021, www.facetsjournal.com/doi/10.1139/facets-2020-0073. Accessed 25 Dec. 2024.

Thomas, M. L. H. “Littoral Communities and Zonation on Rocky Shores in the Bay of Fundy, Canada: An Area of High Tidal Range.” Biological Journal of the Linnean Society 5, no. 1–2 (1994).