Changing Climate

Changing Ocean Chemistry

At least one-quarter of the carbon dioxide released by burning coal, oil, and gas doesn’t stay in the air, but instead dissolves into the ocean. When carbon dioxide and seawater mix, they combine to form carbonic acid. The ocean is becoming more acidic, which is having a harmful effect on many forms of life.

As seawater becomes more acidic, shellfish, crabs, seastars, and sea urchins find it more difficult to build their calcium carbonate shells. Oysters in Puget Sound and off the east coast of Vancouver Island have already experienced reproductive failure because of acidic waters. Scientists predict mussels and oysters to grow less shell by 25 per cent and 10 per cent respectively by the end of the century. For good reason, ocean acidification has been called “climate change’s evil twin.”

In Kwilákm, the loss of mussels, clams, oysters, and other species would have a large effect in the food web, as shellfish are food for many marine bird species. River otters love to feast on shellfish, as do octopi. Oyster and mussel beds create refuges and habitat for juvenile salmon, other small fish such as stickleback, crabs, and many very small creatures.

While the chemistry is predictable, the details of the biological impacts are not. For instance, new calculations made by scientists from the Monterey Bay Aquarium Research Institute suggest that low-oxygen “dead zones” in the ocean could expand significantly over the next century as more and more carbon dioxide dissolves into the ocean. Fish and other marine animals may find it harder to breathe as water becomes more acidic and the dissolved oxygen essential for their life becomes increasingly difficult to extract.

Some Kwilákm natural systems absorb carbon, thereby reducing the effects of climate change. Like plants on land, seaweeds and eelgrass use photosynthesis to absorb carbon dioxide from the water.

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Changing Climate

Hotter Ocean Temperatures

As the world’s oceans absorb heat from the atmosphere, marine life is attempting to shift towards the poles to stay cool. For instance, in recent years, large schools of northern anchovy, more commonly found off the coast of California, have begun making regular appearances in Atl’ka7tsem/Howe Sound and Kwilákm.

Bowen snorkelers now see juvenile anchovy in the summer in Kwilákm, indicating that anchovy have begun breeding here as year-round residents. The anchovy, in turn, have become an important food for humpback whales, sea lions, and seals (all three are doing very well), and seabirds. Interestingly, the number of California sea lions wintering in BC has also increased. Are the sea lions following the anchovy north? More on Anchovy and other forage fish.

Warmer river and ocean temperatures have many negative impacts on cool-water species like the chum salmon raised in the Terminal Creek Fish Hatchery, released into the Lagoon, and living in Kwilákm as juvenile fish. Warmer waters bring more California sea lions to BC waters which, along with a booming seal population, means salmon are facing more predators. The warming sea also means fewer zooplankton (tiny animals drifting in the oceans) that salmon rely on for food. Scientists have calculated it takes roughly one ton of zooplankton to produce a single 5 kg salmon under ideal conditions. High temperatures in the river and creeks where salmon spawn, including in Terminal Creek, cause stress in fish. Salmon can die before reaching spawning grounds. More about Terminal Creek salmon.

As the world’s oceans are warming, some species are stressed or dying out. Others are not feeling the heat at all. Jellyfish, for instance, are thriving in the deoxygenated, warm water resulting from the climate crisis; their numbers are increasing.

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Changing Climate

Rising Sea Levels and Intensifying Winter Storms

As the ocean gets warmer, causing seawater to expand, the level of the sea rises. Melting land-based ice sheets and glaciers, contributing their own water, cause oceans to rise even further. The BC government advises to plan for a one metre rise by 2100 and two metres by 2200. Rising sea levels will damage coastal structures (including homes and docks) and erode the shoreline. Rising water levels at the shore also cause the loss of wildlife habitat and biodiversity.

Extra heat in the air and the oceans is a form of energy, and storms are driven by such energy. The Bay, already subject to winter ocean storm surges, will likely see an increase in the intensity and the frequency of big winter storms that can cause major shoreline erosion.

Property owners often attempt to prevent erosion by removing shoreline native plants and trees and adding seawall, rip rap, and docks (armoured shoreline structures), altering Kwilákm’s natural shoreline.

Ecological understanding of these alterations to the shoreline has changed. Long viewed as relatively benign changes to the shoreline, current science shows that armoured structures cause the loss of wildlife habitat and biodiversity and do not provide protection. Researchers have determined that, in many cases, armouring shorelines will actually increase rates of erosion.

Removal of native trees, shrubs, and vegetation just above the high tide line results in habitat loss for clams and other shellfish, as well as insects, worms, and amphipods that feed forage fish and young salmon. These forage fish and salmon ultimately feed animals at the top of the food web that connects zooplankton, eelgrass, and kelp to salmon, white-sided dolphins, orca, sea lions, and porpoises. What we do on our shores ripples through the food chain.

Green Shores from the Stewardship Centre for BC provides online guides to assist homeowners to understand and protect shoreline forest while also protecting and restoring habitats.

Green Shores use a combination of planting, gravel and sand, logs, stones, and slope modification to protect against shoreline erosion. The natural actions of water and sediment movement maintain healthy shorelines while providing habitat for a diversity of plants and animals.

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Changing Climate

When Seashore Temperatures Spike – Killer Heat Dome 2021

How a Heat Dome Works:

1. Hot air expands upward
2. High pressure pushes warm air down
3. Air compresses, causing heat wave
4. High pressure pushes clouds away

Climate scientists say this is a sign of how dangerous the climate crisis has become — and how much worse it could be. Experts fear extended periods of very high temperatures will have a devastating impact on marine life.

Christopher Harley, a marine biologist at the University of British Columbia, has calculated that more than a billion BC marine animals may have been killed by 2021’s unusual heat. Harley was struck by the smell of rotting mussels, many of which were in effect cooked by the high air temperatures at low tide and abnormally warm water. Other dead creatures decaying in the shallow water included snails, sea stars, clams, and barnacles. “It was an overpowering, visceral experience,” he said.

During the peak of the heat wave, a putrid smell covered some Bowen beaches. One resident of Tunstall Bay said for five days the beach had a very powerful stink, like a dead whale. Now there is a litter of dead mussel shells at the high tide line. On Kwilákm, Will Husby, Bowen citizen scientist, reported about conditions during the heat wave: “On my swims at high tide, I have seen lots of gaping, empty mussel shells on reefs and rocks in the upper intertidal zone in the Bay between Snug Point and well past Pebbly Beach.

However, I have also seen lots of what look to me to be healthy oysters with their siphons open (they close their shells when I touch them). I have also seen barnacles feeding in the upper intertidal.”

While the air hovered around the high 30s, Professor Harley and a student used infrared cameras to record temperatures above 50oC along the rocky shore. Mussels are hardy shellfish, tolerating temperatures into the high 30s. Barnacles are even sturdier, surviving the mid-40s for at least a few hours. “But when the temperatures get above that, those are just unsurvivable conditions,” he said.

“A lot of species are not going to be able to keep up with the pace of change,” Harley said. “Ecosystems are going to change in ways that are really difficult to predict. We don’t know where the tipping points are.”

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