Giant Kelp (Macrocystis pyrifera)
Maegan D. McBride
"Kelp plants are like buildings but very special buildings that are powered completely by solar energy and provide both food and shelter for residents. In this imaginary underwater city, there is recycling, public health, advertising and lots of other things familiar from our own communities. There are also lessons we can take from the kelp bed ecosystem to guide us in creating more sustainable communities on land."
- Richard Murphy, Ocean Futures Society |
Taxonomy
Kingdom: Chromista Subkingdom: Chromista Division: Phaeophyta Class: Phaeophyceae Order: Laminariales Family: Lessoniaceae Genus: Macrocystis Species: pyrifera |
Monterey Bay Aquarium
http://www.montereybayaquarium.org/animals/AnimalDetails
http://www.montereybayaquarium.org/animals/AnimalDetails
Kelp forests are underwater areas with a high density of kelp. They are recognized as one of the most productive and dynamic ecosystems on Earth. [1] Smaller areas of anchored kelp are called kelp beds. Kelp forests occur worldwide throughout temperate and polar coastal oceans.[1] In 2007, kelp forests were also discovered in tropical waters near Ecuador.
Physically formed by brown macroalgae of the order Laminariales, kelp forests provide a unique three-dimensional habitat for marine organisms and are a source for understanding many ecological processes.
Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns[3] and provide many ecosystem services.[4] However, the influence of humans has often contributed to kelp forest degradation. Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the over-grazing of kelp and other algae.[5] This can rapidly result in transitions to barren landscapes where relatively few species persist.[5] The implementation of marine protected areas (MPAs) is one management strategy useful for addressing such issues since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors.
Physically formed by brown macroalgae of the order Laminariales, kelp forests provide a unique three-dimensional habitat for marine organisms and are a source for understanding many ecological processes.
Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns[3] and provide many ecosystem services.[4] However, the influence of humans has often contributed to kelp forest degradation. Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the over-grazing of kelp and other algae.[5] This can rapidly result in transitions to barren landscapes where relatively few species persist.[5] The implementation of marine protected areas (MPAs) is one management strategy useful for addressing such issues since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors.
Science and Technology Focus
/www.onr.navy.mil/focus/ocean/habitats/kelp1.htm
/www.onr.navy.mil/focus/ocean/habitats/kelp1.htm
Macrocystis pyrifera, also known as Giant kelp or Giant bladder kelp, is a species of kelp that is a brownish-greenish color. It is very abundant along the coast of the eastern Pacific Ocean, starting from Baja California north to southeast Alaska. It is also found in the southern oceans near South America, South Africa, and Australia. Individually, fronds of these algae may grow to more than 148 feet long at an astonishing rate of as much as 2 feet per day under ideal conditions. Their blades develop at irregular intervals along the stipe, with a single gas bladder at the base of each blade.[1]
The kelp plant has a root-like holdfast that fixes to rocky surfaces; a long slender stalk or stipe; and long, leaf-like blades or fronds that are the major site of photosynthetic activity. The kelp plant is supported in the water by gas-filled bladders on each frond. [5] The holdfast is cone-shaped and can grow up to 60 cm in diameter in large plants. Giant kelp growth is so dense that they are known for their kelp forests, which are home to many marine animals that depend on the algae for food and shelter. They are the largest of all algae, hence the name. Giant kelp is one of the fastest growing organisms on Earth. [4]
Giant kelp often grows in turbulent water, which brings renewed supplies of nutrients, allowing the plants to grow to a possible height of 175 feet. The stem-like stipes are tough and flexible, allowing the kelp to sway in ocean currents. Unlike most plant root systems that carry nutrients back and forth through the plant, this holdfast, doesn’t carry nutrients or water; it anchors the kelp to a rock. It thrives in cooler waters where the ocean water temperature remains below 70 °F (21 °C). Giant kelp is also related to sea palms and bull kelp and is also considered seaweed.
Giant kelp is a perennial which means it lives for several years while bull kelp is an annual; it completes its life cycle in one year. Both types of kelp have a two-stage life cycle. They exist in their earliest life stages as spores, released with millions of others from the parent kelp, the sporophyte. The spores grow into a tiny male or female plant called a gametophyte, which produces either sperm or eggs. After fertilization occurs, the embryos may grow into mature plants (sporophytes), completing the life cycle.[2] Giant kelp can live up to 7 years.
The kelp plant has a root-like holdfast that fixes to rocky surfaces; a long slender stalk or stipe; and long, leaf-like blades or fronds that are the major site of photosynthetic activity. The kelp plant is supported in the water by gas-filled bladders on each frond. [5] The holdfast is cone-shaped and can grow up to 60 cm in diameter in large plants. Giant kelp growth is so dense that they are known for their kelp forests, which are home to many marine animals that depend on the algae for food and shelter. They are the largest of all algae, hence the name. Giant kelp is one of the fastest growing organisms on Earth. [4]
Giant kelp often grows in turbulent water, which brings renewed supplies of nutrients, allowing the plants to grow to a possible height of 175 feet. The stem-like stipes are tough and flexible, allowing the kelp to sway in ocean currents. Unlike most plant root systems that carry nutrients back and forth through the plant, this holdfast, doesn’t carry nutrients or water; it anchors the kelp to a rock. It thrives in cooler waters where the ocean water temperature remains below 70 °F (21 °C). Giant kelp is also related to sea palms and bull kelp and is also considered seaweed.
Giant kelp is a perennial which means it lives for several years while bull kelp is an annual; it completes its life cycle in one year. Both types of kelp have a two-stage life cycle. They exist in their earliest life stages as spores, released with millions of others from the parent kelp, the sporophyte. The spores grow into a tiny male or female plant called a gametophyte, which produces either sperm or eggs. After fertilization occurs, the embryos may grow into mature plants (sporophytes), completing the life cycle.[2] Giant kelp can live up to 7 years.
University of California Museum of Paleontology
http://ucmp.berkeley.edu/science/research.php
http://ucmp.berkeley.edu/science/research.php
Kelps are thought to have appeared in the Miocene epoch, 23 to 5 million years ago. Brown algal fossils were found in the Monterey Formation of California and documented by Parker and Dawson in 1965. The morphologies of these fossils very closely resemble those of present day kelps. Every algal cell potentially has the ability to photosynthesize and there is generally no complete specialization of different parts of the algae. This is in contrast to terrestrial plants where there are roots, stems, and leaves containing xylem and phloem that have specific, exclusive functions. Kelps however, are the only group of algae that seem to have developed specialized transport tissue. Kelps have trumpet cells that are thought to be similar to the conductive tissue, or phloem, in vascular plants. If you think about the similarities between Macrocystis pyifera in a kelp forest and a tree in a terrestrial forest, there is a need in both systems to be able to transport photosynthetic products from a sun-lit source far above to a shaded sink down below. Algae and terrestrial plants are entirely unrelated yet have a similar way of solving the problem.
The alga that was to eventually be named Macrocystis pyrifera was apparently known by navigators for a long time before it was formally recognized. Johann Gerhard Koenig (1728-1785), a missionary and plant collector, was the first to officially collect the plant. In 1771 Linnaeus named Koenig's specimen, Fucus pyriferus. Linnaeus was the first scientist to formalize the system of naming organisms by genus and species but at the time, had only three categories for all of the algae.
As more specimens were described and greater diversity recognized, a man named Lamouroux created more genera. Lamouroux is responsible for discerning the divisions of green, red, and brown algae that we still recognize today. In 1813 Lamouroux created the genus Laminaria and placed renamed the plant, Laminaria pyriferus. In 1820 Carl Agardh of Sweden published his book on species of algae with descriptions including new the genera: Sargassum, Cystoseira, Macrocystis. In this book he renames Laminaria pyriferus to Macrocystis pyrifera, meaning large bulbs. His collections came from the Ethiopian Sea, Cape of Good Hope, and the Pacific.
The alga that was to eventually be named Macrocystis pyrifera was apparently known by navigators for a long time before it was formally recognized. Johann Gerhard Koenig (1728-1785), a missionary and plant collector, was the first to officially collect the plant. In 1771 Linnaeus named Koenig's specimen, Fucus pyriferus. Linnaeus was the first scientist to formalize the system of naming organisms by genus and species but at the time, had only three categories for all of the algae.
As more specimens were described and greater diversity recognized, a man named Lamouroux created more genera. Lamouroux is responsible for discerning the divisions of green, red, and brown algae that we still recognize today. In 1813 Lamouroux created the genus Laminaria and placed renamed the plant, Laminaria pyriferus. In 1820 Carl Agardh of Sweden published his book on species of algae with descriptions including new the genera: Sargassum, Cystoseira, Macrocystis. In this book he renames Laminaria pyriferus to Macrocystis pyrifera, meaning large bulbs. His collections came from the Ethiopian Sea, Cape of Good Hope, and the Pacific.
Identifying Regions of Persistant Kelp Growth
http://proceedings.esri.com/library/userconf/proc95/to250/p247.html
http://proceedings.esri.com/library/userconf/proc95/to250/p247.html
The size and distribution of giant kelp beds has fluctuated greatly during the past 30 years. Kelp canopies have generally declined since 1967, when the California Department conducted the first statewide survey documenting the size and Distribution of kelp beds . Subsequent surveys in 1988 and 1999 found that kelp beds had declined statewide in each of those years compared to the 1967 level, with the greatest decline occurring along the mainland coast of southern California. This long term decline can be attributed to both natural disturbances such as warm water stress and intense storms associated with El Ninos and human caused disturbances. These disturbances include increased turbidity and siltation associated with coastal development, pollution, and commercial and recreational fishing activities that remove animals such as California
sheephead and California spiny lobster which may help sustain kelp forests through their trophic interactions. [4]
The kelp forests off southern California are considered to be some of the most diverse and productive ecosystems on the planet, yet a new study indicates that today's kelp beds are less extensive and lush than those in the recent past. [6] The kelp forest tripled in size from the peak of glaciation 20,000 years ago to about 7,500 years ago, then shrank by up to 70 percent to present day levels, according to the study by Rick Grosberg, professor in the Department of Evolution and Ecology and the Center for Population Biology at UC Davis, with Michael Graham of the Moss Landing Marine Laboratory and Brian Kinlan at UC
Santa Barbara.
Kelp forests around offshore islands peaked around 13,500 years ago as rising sea levels created new habitat and then declined to present day levels. The kelp along the mainland coast peaked around 5,000 years later. [6] This transition from an extensive island-based kelp system to a mainland-dominated system coincided with conspicuous events in the archaeological record of the maritime people in the region, suggesting that climate-driven shifts in kelp ecosystems impacted human populations that used those resources. Researchers used depth charts of the southern California coastline and formation from sediment cores on past nutrient availability to reconstruct potential kelp habitat as sea levels changed over the last 20,000 years. Essentially, they could reconstruct changes in kelp cover at a scale of 500 years and determine how agmented or connected the populations were. People have lived off the produce of kelp forests when resources on land dwindled, and those changes are recorded in shell middens and other traces. That archaeological record can now be compared with the ecological history to get a more complete picture of California's coast. [4]
sheephead and California spiny lobster which may help sustain kelp forests through their trophic interactions. [4]
The kelp forests off southern California are considered to be some of the most diverse and productive ecosystems on the planet, yet a new study indicates that today's kelp beds are less extensive and lush than those in the recent past. [6] The kelp forest tripled in size from the peak of glaciation 20,000 years ago to about 7,500 years ago, then shrank by up to 70 percent to present day levels, according to the study by Rick Grosberg, professor in the Department of Evolution and Ecology and the Center for Population Biology at UC Davis, with Michael Graham of the Moss Landing Marine Laboratory and Brian Kinlan at UC
Santa Barbara.
Kelp forests around offshore islands peaked around 13,500 years ago as rising sea levels created new habitat and then declined to present day levels. The kelp along the mainland coast peaked around 5,000 years later. [6] This transition from an extensive island-based kelp system to a mainland-dominated system coincided with conspicuous events in the archaeological record of the maritime people in the region, suggesting that climate-driven shifts in kelp ecosystems impacted human populations that used those resources. Researchers used depth charts of the southern California coastline and formation from sediment cores on past nutrient availability to reconstruct potential kelp habitat as sea levels changed over the last 20,000 years. Essentially, they could reconstruct changes in kelp cover at a scale of 500 years and determine how agmented or connected the populations were. People have lived off the produce of kelp forests when resources on land dwindled, and those changes are recorded in shell middens and other traces. That archaeological record can now be compared with the ecological history to get a more complete picture of California's coast. [4]
Numerous natural impacts as well as human activities, affect kelp forest environments. The factors influencing kelp forest stability are diverse: kelp harvesting; grazing by fishes, sea urchins, and crustaceans; plant competition; storms; El Niño events; sedimentation; and pollution. By most accounts, because of its spectacular growth rates, kelp recovers quickly from physical disturbances such as storms that might uproot the fragile plants. However, as in all natural environments, the health is proportional to the number of adverse conditions to which it is exposed. Commercial kelp harvesting is potentially the greatest threat to long-term kelp stability. It has supported a multitude of industries over the past century. From the extractions of kelp during World War I for potash to the modern use of kelp for food additives and pharmaceutical products, kelp has proven to be a dynamic and highly demanded product.
Kelp harvesting during World War I peaked in 1919 when 400,000 wet tons were used to make potash for gunpowder and fertilizer. In the 1930s the food, pharmaceutical, and scientific communities began extracting algin, a thickening, stabilizing, suspending, and gelling agent. Algin is an additive used in a wide variety of dairy products, frozen foods, cakes, puddings, salad dressings, shampoos, and toothpastes. It smooths and thickens ice cream, emulsifies salad dressing, and keeps pigments uniformly mixed in paints and cosmetics.[5] Additionally, some mariculture farms hand-harvest kelp to feed abalone. In the 1980's alone, kelp harvesting supported an industry worth more than $40 million a year, and in 1993, more than 4,700 wet tons of kelp were extracted from the Monterey Bay National Marine Sanctuary.[5]
Large numbers of opaleye or halfmoon fishes can damage kelp forests, particularly when the kelp is exposed to unfavorable growing conditions. As in all ecosystems, a balance exists in this complex environment, and the predators such as sea otters generally reduce populations of sea urchins or grazing fishes enough to limit the damage by grazing. This balance of power is usurped when the predatory populations go into decline, as exemplified by the huge explosion of sea urchins when otter populations suffer from oil spills or disease.
More houses along the coast mean more water pollution, including urban runoff. High energy storms or swells can uproot entire plants and break away fronds. Characterized by severe storms and warm water, El Niño Southern Oscillation Events, often devastate kelp forests. The strong swell activity, winter storms, and warm weather associated with the 1997-1998 El Niño were the primary sources of kelp mortality on the California coast in 1998. [5] Kelp forests south of Point Coneception sustained up to 100 percent mortality in some regions, although comparable habitats north of that region "were relatively unaffected." [5]
Researchers attribute the discrepancy between southern and central California to ocean temperature gradients; the El Niño brought unusually high ocean temperatures to southern California where the heat degraded the health of the giant kelp forests. The combined warm water temperature and strong wave energy caused high mortality in the south. Central California bull kelp forests remained in cooler waters and thus in better condition when the winter swells hit, and a much greater percent survived. Non-point and point source pollution including sewage, industrial disposal, and coastal runoff might contribute to kelp forest degradation. For instance, high sedimentation from coastal run-off may bury new plant shoots. Similarly, kelp may experience reduced growth rates and reproductive success in more toxic waters and sediments. Studies on microscopic stages of kelp suggest that kelp is sensitive to sewage, industrial waste discharges, and other causes of poor water and sediment quality. Kelp monitoring projects actively continue in the four sanctuaries. With ongoing surveys of kelp extent, physical oceanic conditions, and associated biota, the researchers will gain a more complete understanding of natural and antropogenic impacts on kelp forests.[5]
Kelp harvesting during World War I peaked in 1919 when 400,000 wet tons were used to make potash for gunpowder and fertilizer. In the 1930s the food, pharmaceutical, and scientific communities began extracting algin, a thickening, stabilizing, suspending, and gelling agent. Algin is an additive used in a wide variety of dairy products, frozen foods, cakes, puddings, salad dressings, shampoos, and toothpastes. It smooths and thickens ice cream, emulsifies salad dressing, and keeps pigments uniformly mixed in paints and cosmetics.[5] Additionally, some mariculture farms hand-harvest kelp to feed abalone. In the 1980's alone, kelp harvesting supported an industry worth more than $40 million a year, and in 1993, more than 4,700 wet tons of kelp were extracted from the Monterey Bay National Marine Sanctuary.[5]
Large numbers of opaleye or halfmoon fishes can damage kelp forests, particularly when the kelp is exposed to unfavorable growing conditions. As in all ecosystems, a balance exists in this complex environment, and the predators such as sea otters generally reduce populations of sea urchins or grazing fishes enough to limit the damage by grazing. This balance of power is usurped when the predatory populations go into decline, as exemplified by the huge explosion of sea urchins when otter populations suffer from oil spills or disease.
More houses along the coast mean more water pollution, including urban runoff. High energy storms or swells can uproot entire plants and break away fronds. Characterized by severe storms and warm water, El Niño Southern Oscillation Events, often devastate kelp forests. The strong swell activity, winter storms, and warm weather associated with the 1997-1998 El Niño were the primary sources of kelp mortality on the California coast in 1998. [5] Kelp forests south of Point Coneception sustained up to 100 percent mortality in some regions, although comparable habitats north of that region "were relatively unaffected." [5]
Researchers attribute the discrepancy between southern and central California to ocean temperature gradients; the El Niño brought unusually high ocean temperatures to southern California where the heat degraded the health of the giant kelp forests. The combined warm water temperature and strong wave energy caused high mortality in the south. Central California bull kelp forests remained in cooler waters and thus in better condition when the winter swells hit, and a much greater percent survived. Non-point and point source pollution including sewage, industrial disposal, and coastal runoff might contribute to kelp forest degradation. For instance, high sedimentation from coastal run-off may bury new plant shoots. Similarly, kelp may experience reduced growth rates and reproductive success in more toxic waters and sediments. Studies on microscopic stages of kelp suggest that kelp is sensitive to sewage, industrial waste discharges, and other causes of poor water and sediment quality. Kelp monitoring projects actively continue in the four sanctuaries. With ongoing surveys of kelp extent, physical oceanic conditions, and associated biota, the researchers will gain a more complete understanding of natural and antropogenic impacts on kelp forests.[5]
1. http://www.geol.utas.edu.au/kelpwatch/h_tas.html
2. http://proceedings.esri.com/library/userconf/proc95/to250/p247.html
3. Steneck, R.S., M.H. Graham, B.J. Bourque, D. Corbett, J.M. Erlandson, J.A. Estes and M.J. Tegner. 2002.
Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation 29: 436-459.
4. /www.onr.navy.mil/focus/ocean/habitats/kelp1.htm
5. http://sanctuaries.noaa.gov/visit/ecosystems/kelpimpacts.html
6. http://www.sciencedaily.com/releases/2009/11/091111092049.htm
2. http://proceedings.esri.com/library/userconf/proc95/to250/p247.html
3. Steneck, R.S., M.H. Graham, B.J. Bourque, D. Corbett, J.M. Erlandson, J.A. Estes and M.J. Tegner. 2002.
Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation 29: 436-459.
4. /www.onr.navy.mil/focus/ocean/habitats/kelp1.htm
5. http://sanctuaries.noaa.gov/visit/ecosystems/kelpimpacts.html
6. http://www.sciencedaily.com/releases/2009/11/091111092049.htm