Day 3: Ocean Forests

Question of the Day:

How does kelp help the shore?

Character of the Day:

Ocean Life: While some salmon remain in coastal water, others migrate northward to feedings grounds. Salmon may spend one to seven years in the ocean. Certain species have more flexible life history strategies, while others are more rigid. Coho may spend up to seven years at sea, but typically four. Pink salmon, on the other hand, spend a fixed 18 months at sea. Sockeye typically spend two years at sea, and chinook can spend up to 8 years before journeying back to their natal streams to spawn.

Key Concepts:

(Authored by Dr. Kyle Demes, postdoctoral fellow, Salomon group, REM, SFU) Kelps are technically algae, not plants, (in the Order Laminariales) and are actually more closely related to water molds than they are to land plants! Kelp beds typically grow in coastal regions in depths from a few meters to over a 100 m deep. There are just over 100 species of kelp distributed in shallow temperate oceans across the globe. All species are highly productive and provide 3-dimensional habitat for fish, invertebrates, and other algae, creating diverse communities referred to as kelp forests.

The giant kelp forests of the California coastline are world-renown for their size, diversity of species, and productivity (which rivals coral reefs). The giant kelp, Macrocystis pyrifera, is one of the fastest growing organisms on the planet (up to 60 cm a day) and can reach heights of over 30 m. Because the kelps themselves are foundational species in this ecosystem, they carry immense ecological and economic importance. In addition to providing habitat to other algae and animals, kelps are an important industrial resource [as a source for alginate which is in everything from make-up and medicine to toothpaste and ice cream], which can be harvested sustainably in large quantities because of giant kelp’s fast growth rates. Unlike trees, which are cut down and killed during harvested, kelp biomass is harvested from the surface of the water, allowing the base of the kelp to survive and continue growing.

To reproduce, adult kelps produce spores (on the order of trillions!), half of which are male and half of which are female. These spores then attach to rock on the seabed and grow into male and female parts, which never grow large enough to be visible to the naked eye. Once these male and female parts are reproductive, the female part releases a pheromone. This pheromone signals the male parts to release their material, which then tracks the pheromone to fertilize a type of egg- this fertilization event will result in the production of the large kelps that we are used to seeing. Understanding this microscopic life history stage allows for kelp forests to regenerate after a catastrophic die-off, such as that which can be induced by wave action.

Kelp beds provide a resting area for otters, gulls, herons, shorebirds, and waterfowl. Underwater kelp forests shelter snails, crabs, shrimp, starfish, sea anemones, sea cucumbers, brittle stars, sea squirts, and many other marine creatures.

Climate change poses several important threats to kelp forests. Even slight elevations in temperature can result in decreased productivity, growth, and reproduction in kelps. However, changes in ocean acidity, as a consequence of increased carbon dioxide (CO2) dissolution in the ocean may inhibit kelp reproduction. Less well understood is how well kelp may respond to climate change effects such as ocean salinity changes and increased storm severity and frequency. With rising global temperatures, there is more snowmelt every year and this freshwater finds its way to the ocean. More freshwater intrusion into the ocean decreases salinity, and cause kelps to die. Lastly, climate change scenarios predict more frequent and more severe storm events. In California, wave-induced ocean forces are the largest cause of death among kelps, so more storms mean that more kelp will die, which has been shown to decrease the diversity of species living in theecosystem.

(Byrnes et al 2011). BYRNES, J. E., REED, D. C., CARDINALE, B. J., CAVANAUGH, K. C., HOLBROOK, S. J. and SCHMITT, R. J. (2011), Climate-driven increases in storm frequency simplify kelp forest food webs. Global Change Biology, 17: 2513–2524.

Cool Facts

Entire growth of kelp occurs spring to fall, up to 2 feet per day. Kelp can grow to 200 feet in ocean waters..

Gas Floats: Bulbous float at the end is filled with gas containing carbon monoxide (CO).

Rafts of kelp help reduce beach erosion. Kelp forests soften the force of waves against the shoreline. This protection can be seen along the Lost Coast where large kelp beds form bay-like areas along the shoreward side. These bay-like waters provide feeding areas for birds, including loons, scoters, grebes, goldeneyes, and buffleheads.

Youth Ambassador Activity:

Measure size of kelp washed ashore on the beaches. Size, number, etc. Maybe select some for sampling at dinner!

Daily Dispatch:

Twice each day, the sandy beach is washed clean of all evidence. Bu the evidence sometimes doesn’t disappear, it is just moved to another location. On this beach, the Youth Ambassadors walked, toes digging deep into the sand with each step. They were not climbing in elevation, but the effort to put one foot in front of the other certainly seemed like it. In this space, the Youth Ambassadors soon grew quiet in their conversation, but more loudly in their reflections of the past few days and what they were observing in the moment. They flipped over kelp fronds that had washed ashore, only to jump back in as much surprise and delight at the underside’s trove of treasures. Sheltered under each frond was an oasis, teaming with life, amongst an endless stretch of sand. As the kilometers passed, they came upon a headland, and beyond it several bays that saw them leave the sand, and walk amongst what might become sands in the distant future. Hoping from rock to rock, the youth ambassadors were again welcomed to a new environment. Canopies of kelp waved to those on shore from their pools and bays of seeming protection from the surf. The Youth Ambassadors continued on, sometimes under the watchful eyes of seal lions and a few sea otters. As comfortable as those creatures looked in their environment, the Youth Ambassadors new better than to jump into those frigid waters to play with the locals, and perhaps feast with them. As the hours passed by, so to did the distance. With the expedition team having reached their campsite, they shed their heavy packs and pitched their tents. Simple foods had never tasted so good, and all ravenously emptied their bowls. With the arrival of darkness, yet under the friendly glow of a ¾ moon, the Youth Ambassadors reflected on their observations as they traveled along the coast. Soon the one yawn lead to many, and all retied to the comfortable confines of their cocoons to sooth sore muscles in their sleep. Even though all were exhausted, they were treated to a symphony. The rhythmic pounding of waves on the shore shook the ground at times, it no doubt was the base. Joining in were the sea lions, parked on an offshore rock, who barked the night away. Soon all were sound asleep.