The Intertidal and Kelp Forests - Pacific Coast
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Basic lecture on the Pacific Intertidal Ecology and Kelp Forest Ecology
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The Intertidal and Kelp Forests - Pacific Coast
- 1. The Intertidal and Kelp Forests: Pacific Coast BIO-110 Spring, 2021
- 2. “Coastal Ecosystems” “In 1995 more than 2.2 billion people, 39% of the world's population, lived within 100 kilometers (km) of a coastline. Add to these the millions more who vacation in coastal regions annually. In 1997 more than 18.8 million tourists visited the Caribbean alone. “Coastal ecosystems are also an important food source. In 1997, 64 million metric tons of fish and shellfish were harvested from oceans and inland waters and 29 million metric tons from aquaculture for human consumption. Another 29 million metric tons were processed for animal feed. “
- 4. “Natural and Altered Landcover within 100Km of a Coast” http://www.pbs.org/earthonedge/ecosystems/coastal1.html
- 5. “Biogeochemistry” “Biogeochemistry has matured as a scientific discipline as we have come to recognize that the current human impact on our planet may disrupt the stable chemistry of our evolutionary environment, which is at least partially determined by the diversity of species that occupy this planet with us. The level of CO2 in the atmosphere, the amount of precipitation that falls on land, the content of nitrogen and phosphorus in rivers, and the silicon that is deposited in ocean sediments are all determined by biota – ranging from bacteria to higher plants. Life’s diversity – the bio in biogeochemistry – performs a great service to us, which we must understand better if we are to preserve its function.” David M. Karl, William H. Schlesinger, in Treatise on Geochemistry (Second Edition), 2014 https://www.sciencedirect.com/topics/earth-and-planetary-sciences/coastal-landscape/pdf
- 6. “Salt Marsh Biogeochemistry—An Overview” “Salt marshes are fluid in terms of geomorphology, biogeochemistry, and their role in the coastal landscape. They are subject to the synergistic effects of global scale climate forcings and local-scale human impacts… there has been a large increase in the number of published papers that have examined biogeochemical responses to environmental changes such as increased atmospheric CO2 concentrations, eutrophication of coastal waters, and climate change/global warming. Salt marsh responses to these and other stressors occur at the scale of soil biogeochemistry, plant productivity, and geomorphology and may likely alter the role of marshes in the coastal landscape. “ -- Craig Tobias, Scott C. Neubauer, “Salt Marsh Biogeochemistry—An Overview,” (in Coastal Wetlands, 2019)
- 7. NOAA: Tides and Currents “The word "tides" is a generic term used to define the alternating rise and fall in sea level with respect to the land, produced by the gravitational attraction of the moon and the sun. To a much smaller extent, tides also occur in large lakes, the atmosphere, and within the solid crust of the earth, acted upon by these same gravitational forces of the moon and sun. Additional nonastronomical factors such as configuration of the coastline, local depth of the water, ocean-floor topography, and other hydrographic and meteorological influences may play an important role in altering the range, interval between high and low water, an times of arrival of the tides. “The most familiar evidence of the tides along our seashores is the observed recurrence of high and low water - usually, but not always, twice daily. The term tide correctly refers only to such a relatively short-period, astronomically induced vertical change in the height of the sea surface (exclusive of wind-actuated waves and swell); the expression tidal current relates to accompanying periodic horizontal movement of the ocean water, both near the coast and offshore (but as distinct from the continuous, stream-flow type of ocean current). “Knowledge of the times, heights, and extent of inflow and outflow of tidal waters is of importance in a wide range of practical applications such as the following: Navigation through intracoastal waterways, and within estuaries, bays, and harbors; work on harbor engineering projects, such as the construction of bridges, docks, breakwaters, and deep-water channels; the establishment of standard chart datums for hydrography and for demarcation of a base line or "legal coastline" for fixing offshore territorial limits both on the sea surface and on the submerged lands of the Continental Shelf; provision of information necessary for underwater demolition activities and other military engineering uses; and the furnishing of data indispensable to fishing, boating, surfing, and a considerable variety of related water sport activities.” https://tidesandcurrents.noaa.gov/restles1.html
- 10. “Between Pacific Tides”: Coastal Systems Protected Outer Coast Outer-Coast Rocky Shores Outer-Coast Sandy Beaches Open Coast Open-Coast Rocky Shores Open-Coast Sandy Beaches Bays and Estuaries Rocky Shores of Bays and Estuaries Sand Flats Eelgrass Flats Mud Flats Wharf Piling Exposed Piles Protected Piles
- 11. “Outer-Coast Sandy Beaches” “PRESUMABLY because of their usually limited extent, the sandy beaches of the protected outer coast are the most barren of all intertidal areas. They occupy a strange position, biologically speaking. They are distinct, on the one hand, from the typical Pacific sandy beach, which is completely exposed and subjected to violent surf but nevertheless supports a highly specialized fauna, although it is neither abundant nor greatly varied. In closed bays, sounds, and sloughs, on the other hand, we find the completely protected sandy beaches supporting a fauna both rich and varied. No doubt the total area available for colonization is the chief factor in both the latter cases, for characteristic animals will not develop for a type of region that is represented by small and widely separated areas only, like the sandy beaches in question. Such beaches ordinarily occur in short stretches of a few hundred yards or a few miles, between outcroppings of rock and are almost destitute of life. It might reasonably be asked why such areas are not colonized by the animals of surf-swept beaches; the answer is, apparently, that the animals of surf-swept beaches will not tolerate the more sheltered conditions. The same answer, reversed, would apply to completely protected bay animals, for whom these areas would be too exposed. At any rate, barrenness is the rule, and we have three animals to record from the semi-sheltered sandy beaches, ignoring those forms which may occasionally be washed up from other habitats. “
- 17. Primary Forces in the Intertidal Environment Desiccation Light Salinity Wave Shock/ Sand Scour/ Rock Movement Predation Competition: Food/ Space Intra-specific: mates Inter-specific
- 18. Sand Scour
- 19. Seaweed Lash
- 23. Moon Snail and Cockles https://www.shapeoflife.org/video/molluscs-moon-snail-preys-cockles
- 24. Kelp Forests
- 26. https://www.youtube.com/watch?v=kJv0eYQp1lo https://www.montereybayaquarium.org/animals/live-cams
- 30. “Beach Wrack”??? “Spiller found that washed-up seaweed is in fact a resource "subsidy" that's consumed by flies and small amphipods such as beach fleas, which in turn are eaten by lizards and predatory arthropods like spiders. “Seaweed also decomposes directly into the soil, providing nutrients to plants. In the study, the growth rate of land-based plants near seaweed-subsidized plots was 70 percent higher than in non-seaweed-subsidized plots. “In subsidized plots, the density of lizards also increased rapidly, averaging 63 percent higher than in non-subsidized plots. In addition, lizards shifted their diets to marine-based prey. “When clumps of seaweed appeared on the scene, they attracted marine amphipods that reproduce rapidly. Lizards then went from land-based vegetation to seaweed to feast on the treasure trove. “The addition of seaweed also led to an increase in insect damage to plants living along the beach. When lizards moved to seaweed from land-based vegetation, their usual prey--plant- eating insects--were free to go on a spree, decimating plant leaves as they munched. ” ‘What we saw may be called a 'fertilization effect' in which seaweed adds nutrients to plants, increasing their growth rate,’ says Spiller, ‘and a 'predator-diet-shift effect' in which lizards shift from eating land-based prey to consuming small, marine detritivores that breed in seaweed.’ " https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=124910&org=NSF
- 33. (A) Number of sites in the dataset (n = 1,454) by ecoregion (16). Kira A. Krumhansl et al. PNAS 2016;113:48:13785-13790 ©2016 by National Academy of Sciences KA Krumhansl, et al. “Global patterns of kelp forest change over the past half-century,” PNAS November 29, 2016 113 (48) 13785- 13790; first published November 14, 2016 https://doi.org/10.1073/p nas.1606102113
- 39. https://www.youtube.com/watch?v=rXhy1LNqQ60 James Estes (UC Santa Cruz)
- 41. https://www.youtube.com/watch?v=rXhy1LNqQ60 James Estes (UC Santa Cruz)
- 42. https://www.youtube.com/watch?v=rXhy1LNqQ60 James Estes (UC Santa Cruz)
- 43. “Just a few hundred years ago, thousands of sea otters peppered the coast of California, dwarfing the current population of less than 3000 animals. A host of human impacts are to blame for keeping otters near the edge of extinction today—loss of habitat, competition for food, diseases carried by our pets and oils spills, to name just a few. But only the fur trade could whittle the otter population down to the few dozen that were left in the early 1900s. “When Russian explorer Vitus Bering stumbled upon a group of otters living on the Commander Islands in 1741, he probably didn’t anticipate that these animals would play a role in changing boundary lines on the world map and unhinging the fragile coastal ecosystem of North America. What was clear was the value of their pelts. With up to a million hairs per square inch, otter fur was prized for its softness and warmth—the warmest in the animal kingdom. For comparison, we only have about 100,000 hairs on our heads. “Until the late 19th century, Russian fur traders hop scotched through Alaska’s Aleutian Islands, killing most of the curious, slow-moving otters in their path and then shipping the furs off to profitable markets in back home in Russia and in China, Japan, and Europe. In the process, the hunters decimated a relative of the manatee called the Stellar’s sea cow (Hydrodamalis gigas). These slow-swimming kelp-eaters provided the on-the-go meals the hunters needed. But unlike sea otters, the sea cows didn’t survive the onslaught. The otter fur trade wiped them from existence.” Fur Trade
- 50. https://www.researchgate.n et/figure/Comparison-of- sea-otter-a-and-sea-urchin- b-dominated-communities- a-Sea- otters_fig2_257786359 P. Szpak, et al. “Regional ecological variability and impact of the maritime fur trade on nearshore ecosystems in southern Haida Gwaii (British Columbia, Canada): Evidence from stable isotope analysis of rockfish (Sebastes spp.) bone collagen.” June 2013 Archaeological and Anthropological Sciences 5(2)
- 61. “Kelp forests are strongly influenced by macroinvertebrate grazing on fleshy macroalgae. In the North Pacific Ocean, sea otter predation on macroinvertebrates substantially reduces the intensity of herbivory on macroalgae. Temperate Australasia, in contrast, has no known predator of comparable influence. These ecological and biogeographic patterns led us to predict that (i) the intensity of herbivory should be greater in temperate Australasia than in the North Pacific Ocean; thus (ii) Australasian seaweeds have been under stronger selection to evolve chemical defenses and (iii) Australasian herbivores have been more strongly selected to tolerate these compounds. We tested these predictions first by measuring rates of algal tissue loss to herbivory at several locations in Australasian and North Pacific kelp forests. There were significant differences in grazing rates among sea otter-dominated locations in the North Pacific (0-2% day- 1), Australasia (5-7% day-1), and a North Pacific location lacking sea otters (80% day-1). The expectations that chronically high rates of herbivory in Australasia have selected for high concentrations of defensive secondary metabolites (phlorotannins) in brown algae and increased tolerance of these defenses in the herbivores also were supported… These findings suggest that top-level consumers, acting through food chains of various lengths, can strongly influence the ecology and evolution of plantherbivore interactions.” __ Steinberg, et al. “Evolutionary Consequences of Food Chain Length in Kelp Forest Communities,” PNAS 92:18 8145-8148 (1995) https://www.pnas.org/content/92/18/8145
Notes de l'éditeur
- (A) Number of sites in the dataset (n = 1,454) by ecoregion (16). Gray shading indicates ecoregions where kelps are present but for which no data were available. (B) Range of dates within each study within each ecoregion, with line shading indicating the weight of studies within that range.