

@mastersthesis {7230,
	title = {Investigating the influence of allochthonous subsidies on nearshore giant kelp forests in {Big} {Sur}, {California}},
	year = {2009},
	note = {3394667},
	school = {University of California, Santa Cruz},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {Nearshore marine ecosystems are located at the land-sea interface where they are connected to other habitats through the movement of subsidies across habitat borders. How these subsidies structure nearshore marine communities, how temporal and spatial variations in subsidy delivery drive processes, and under what conditions these subsidies are important, however, are not well understood. To investigate the influence of subsidies from open ocean and terrestrial habitats on nearshore giant kelp forests, I used a combination of water chemistry analyses, community surveys, and stable isotope analyses to address the following; (1) what subsidies are delivered from terrestrial and open ocean habitats? (2) does proximity to stream input influence kelp forest community structure? (3) does the use of terrestrial and open ocean subsidies by the giant kelp Macrocystis vary across space and time? (4) what is the contribution of allochthonous versus autochthonous food resources to kelp forest consumers? Dissolved inorganic nutrients were most abundant when delivery from open ocean habitats was greatest due to upwelling circulation. The contribution of dissolved inorganic nutrients through stream outflow was consistently low throughout the year, including during high-flow events. The concentration of particulate organic matter in stream outflow, however, increased dramatically during high-flow events. Chlorophyll-a concentration was low throughout the year, which is uncommon for a coastal upwelling system. Dissolved iron measurements revealed that iron should not limit phytoplankton growth in nearshore kelp beds; phytoplankton incubations suggested that transport of phytoplankton offshore was likely limiting production in the region. Kelp forest community structure was influenced by proximity to river input. This effect was due to the high abundance of sand that reduced benthic algal and invertebrate species richness at one of my sites. There was also a significant difference in the number of Macrocystis individuals at sites close-to versus far-from stream input. There was a significant seasonal difference in δ13 C and δ15 N isotope values in Macrocystis . This variation was strongly negatively correlated with both upwelling strength and nitrate concentration; δ13 C and δ15 N values were low during the spring and early summer when upwelling strength and nitrate concentration tend to be greatest. The autochthonous production of Macrocystis contributed between 60 and 90\% to the isotope values in kelp forest primary consumers. Allochthonous contributions from phytoplankton were intermediate and terrestrial contributions were lowest. This highly skewed contribution of Macrocystis to primary consumers is different from other coastal upwelling systems where phytoplankton tends to be the dominant food source.},
	keywords = {0416:Biological oceanography, Allochthonous subsidies, Biological oceanography, Biological sciences, Giant kelp forests, Macrocystis, Primary production},
	url = {http://search.proquest.com/docview/304858937?accountid=14270},
	author = {Foley, Melissa M.}
}
