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dos ballenas · 10-13-2015, 02:13 PM

Giant Kelp Canopy Cover and Biomass Estimates from High Resolution SPOT Imagery off Santa Barbara, California fficeffice" />>>

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Kyle C Cavanaugh¹, David A Siegel¹, Brian P Kinlan², Dan C Reed³ >>

> >

¹ Institute for Computational Earth System Science,>>

University of California, Santa Barbara,>>

Santa Barbara, CA 93106-3060, USA>>

> >

² Department of Ecology, Evolution, and Marine Biology>>

University of California, Santa Barbara >>

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³ Marine Science Institute>>

University of California, Santa Barbara>>

Giant kelp (Macrocystis pyrifera) is important both as a valuable renewable natural resource and as the basis for one of the most productive ecosystems in the world. The plant itself has great economic value and is harvested for use in a wide variety of products ranging from pharmaceuticals to cosmetics to food products. Perhaps more importantly, giant kelp is an “ecosystem engineer” that provides both food and three-dimensional habitat structure to a diverse array of biologically and commercially important species of algae, invertebrates, fish, and marine mammals (ffice:smarttags" />lace w:st="on">Daytonlace> 1985). Macrocystis also plays a major role in the marine carbon cycle as kelp forests are extremely fast growing and have productivity levels comparable to tropical rainforests (Mann 1973). Because of this high productivity, kelp forests export large quantities of organic matter to adjacent littoral (Polis & Hurd 1996) and continental shelf (Vetter & Dayton 1999) systems. >>
Kelp growth and mortality is regulated by a number of factors including water temperature, depth, bottom type, wave action, competition with other species, and anthropogenic impact (lace w:st="on">Daytonlace>, 1985). Increased wave action from winter storms is one of the most common sources of plant mortality (Dayton, 1985; Ebeling et al. 1985). This typically gives giant kelp populations in southern lace w:st="on">Californialace> a seasonal cycle of late fall highs and early spring lows. In addition, the frequency and intensity of the winter storm season varies annually, leading to large fluctuations in population size from year to year (Dayton et al, 1992). The effects of storm mortality vary spatially as well as temporally and are controlled by gradients in bottom type and wave exposure (Graham et al, 1997). On larger time and spatial scales El Nino/Southern Osciallation (ENSO) cycles bring warmer waters and decreased nutrient levels which can cause mortality and prevent recovery of populations (Dayton and Tegner 1989). Because many of the controls on kelp populations are variable on a number of different temporal and spatial scales, the abundance, extent, and condition of giant kelp forests vary dramatically over space and time.>>
While the morphologies and growth habits of kelps are vast, this study is only concerned with the giant kelp Macrocystis pyrifera, by far the most common canopy forming kelp in lace w:st="on">Southern Californialace>. An adult Macrocystis plant consists of a bundle of vine-like fronds buoyed by small gas bladders and anchored to hard substrate by a common holdfast. Hard substrate is a requisite for giant kelp survival and acts as one of the major determinants of suitable kelp habitat in lace w:st="on">Southern Californialace>. Individual kelp fronds grow rapidly (up to 0.5 m/day), and shed large quantities of macroscopic, particulate, and dissolved organic matter into the surrounding ecosystem.Once they reach the surface fronds grow horizontally up to sixty feet and create an extremely dense surface canopy. Large beds of kelp can form a collective canopy of over 160 hectares in area. This surface canopy makes kelp forests distinctive when viewed from above and therefore suitable for aerial and satellite mapping. >>
Previous studies (Jensen et al, 1980; Augenstein et al, 1991; Deysher 1993) have successfully mapped kelp canopy using various types of aerial and satellite imagery. Jensen (1980), Augenstein (1991), and Deysher (1993) found that multispectral satellite data with 20 and 30 meter resolution was sufficient for mapping the distribution of large (>10 ha) kelp beds in Southern California and quantifying their areal extent. However, these earlier studies have been both spatially and temporally limited; in all cases less than 4 different dates were analyzed for less than 20 km of coastline. The California Department of Fish and Game has conducted higher resolution (2 m) aerial surveys of giant kelp canopy for the entire lace w:st="on">Californialace> coastline in 1989, 1999, and annually from 2002 to 2006. These surveys are performed in the fall when kelp beds are at or near their maximum size. However, this annual coverage is not sufficient to resolve the seasonal variations in kelp populations and to identify the mechanisms of these variations. By increasing the frequency and area of satellite image acquisitions, we hope to better understand kelp population dynamics in relation to biophysical forcings on monthly to annual timescales.>>

10-13-2015, 02:13 PM	#16
dos ballenas Vampyroteuthis infernalis Join Date: Nov 2005 Posts: 585	Giant Kelp Canopy Cover and Biomass Estimates from High Resolution SPOT Imagery off Santa Barbara, California fficeffice" />>> > > > > Kyle C Cavanaugh¹, David A Siegel¹, Brian P Kinlan², Dan C Reed³ >> > > ¹ Institute for Computational Earth System Science,>> University of California, Santa Barbara,>> Santa Barbara, CA 93106-3060, USA>> > > ² Department of Ecology, Evolution, and Marine Biology>> University of California, Santa Barbara >> > > ³ Marine Science Institute>> University of California, Santa Barbara>> Giant kelp (Macrocystis pyrifera) is important both as a valuable renewable natural resource and as the basis for one of the most productive ecosystems in the world. The plant itself has great economic value and is harvested for use in a wide variety of products ranging from pharmaceuticals to cosmetics to food products. Perhaps more importantly, giant kelp is an “ecosystem engineer” that provides both food and three-dimensional habitat structure to a diverse array of biologically and commercially important species of algae, invertebrates, fish, and marine mammals (ffice:smarttags" />lace w:st="on">Daytonlace> 1985). Macrocystis also plays a major role in the marine carbon cycle as kelp forests are extremely fast growing and have productivity levels comparable to tropical rainforests (Mann 1973). Because of this high productivity, kelp forests export large quantities of organic matter to adjacent littoral (Polis & Hurd 1996) and continental shelf (Vetter & Dayton 1999) systems. >> Kelp growth and mortality is regulated by a number of factors including water temperature, depth, bottom type, wave action, competition with other species, and anthropogenic impact (lace w:st="on">Daytonlace>, 1985). Increased wave action from winter storms is one of the most common sources of plant mortality (Dayton, 1985; Ebeling et al. 1985). This typically gives giant kelp populations in southern lace w:st="on">Californialace> a seasonal cycle of late fall highs and early spring lows. In addition, the frequency and intensity of the winter storm season varies annually, leading to large fluctuations in population size from year to year (Dayton et al, 1992). The effects of storm mortality vary spatially as well as temporally and are controlled by gradients in bottom type and wave exposure (Graham et al, 1997). On larger time and spatial scales El Nino/Southern Osciallation (ENSO) cycles bring warmer waters and decreased nutrient levels which can cause mortality and prevent recovery of populations (Dayton and Tegner 1989). Because many of the controls on kelp populations are variable on a number of different temporal and spatial scales, the abundance, extent, and condition of giant kelp forests vary dramatically over space and time.>> While the morphologies and growth habits of kelps are vast, this study is only concerned with the giant kelp Macrocystis pyrifera, by far the most common canopy forming kelp in lace w:st="on">Southern Californialace>. An adult Macrocystis plant consists of a bundle of vine-like fronds buoyed by small gas bladders and anchored to hard substrate by a common holdfast. Hard substrate is a requisite for giant kelp survival and acts as one of the major determinants of suitable kelp habitat in lace w:st="on">Southern Californialace>. Individual kelp fronds grow rapidly (up to 0.5 m/day), and shed large quantities of macroscopic, particulate, and dissolved organic matter into the surrounding ecosystem.Once they reach the surface fronds grow horizontally up to sixty feet and create an extremely dense surface canopy. Large beds of kelp can form a collective canopy of over 160 hectares in area. This surface canopy makes kelp forests distinctive when viewed from above and therefore suitable for aerial and satellite mapping. >> Previous studies (Jensen et al, 1980; Augenstein et al, 1991; Deysher 1993) have successfully mapped kelp canopy using various types of aerial and satellite imagery. Jensen (1980), Augenstein (1991), and Deysher (1993) found that multispectral satellite data with 20 and 30 meter resolution was sufficient for mapping the distribution of large (>10 ha) kelp beds in Southern California and quantifying their areal extent. However, these earlier studies have been both spatially and temporally limited; in all cases less than 4 different dates were analyzed for less than 20 km of coastline. The California Department of Fish and Game has conducted higher resolution (2 m) aerial surveys of giant kelp canopy for the entire lace w:st="on">Californialace> coastline in 1989, 1999, and annually from 2002 to 2006. These surveys are performed in the fall when kelp beds are at or near their maximum size. However, this annual coverage is not sufficient to resolve the seasonal variations in kelp populations and to identify the mechanisms of these variations. By increasing the frequency and area of satellite image acquisitions, we hope to better understand kelp population dynamics in relation to biophysical forcings on monthly to annual timescales.>> __________________ ____________________________________________