scholarly journals Remarkable invasion of San Francisco Bay (California, USA), by the Asian clam Potamocorbula amurensis. II, Displacement of a former community

1990 ◽  
Vol 66 ◽  
pp. 95-101 ◽  
Author(s):  
FH Nichols ◽  
JK Thompson ◽  
LE Schemel
Keyword(s):  
San Francisco ◽  
San Francisco Bay ◽  
Asian Clam ◽  
Potamocorbula Amurensis

Using stable isotopes to monitor watershed influences on aquatic trophodynamics

1999 ◽  
Vol 56 (11) ◽  
pp. 2167-2171 ◽  
Author(s):  
Brian Fry
Keyword(s):  
San Francisco ◽  
Nutrient Loading ◽  
San Francisco Bay ◽  
Estuarine System ◽  
Potamocorbula Amurensis ◽  
Isotopic Compositions ◽  
Carbon Isotopic ◽  
Routine Monitoring ◽  
C And N

Stable C and N isotope measurements of the clam Potamocorbula amurensis were used to help identify watershed-level differences in food webs of San Francisco Bay. Potamocorbula amurensis has become widely distributed in San Francisco Bay since introduction from Asia in1986. Clam samples were collected from both the river-influenced northern arm of San Francisco Bay and the lagoonal southern arm of the Bay during 1990-1991. Carbon isotopic compositions of clams responded primarily to riverine inputs and provided an index of hydrologic mixing across the estuarine system. Nitrogen isotopic compositions of clams were more responsive to watershed nutrient loading, with higher δ15N values found in South Bay, which receives stronger inputs of anthropogenic N. Routine monitoring of animal consumer isotopic compositions could be an effective way to detect long-term watershed-level changes in C and N dynamics important for secondary production in aquatic systems.

A biostratigraphic record of Anthropocene ecological change in one of the world's most invaded aquatic ecosystems, San Francisco, CA.

2021 ◽  
Author(s):  
Stephen Himson ◽  
Mark Williams ◽  
Mary McGann ◽  
Neil Rose ◽  
Ian Wilkinson ◽  
...  
Keyword(s):  
Fly Ash ◽  
High Resolution ◽  
San Francisco ◽  
Native Species ◽  
San Francisco Bay ◽  
Marine Ecology ◽  
Radiometric Dating ◽  
Ecological Change ◽  
Potamocorbula Amurensis ◽  
River Region

<p>Modification of ecosystems through the introduction of non-native species (neobiota) is one part of the major human impact on the biosphere. Neobiota are now present worldwide and often significantly outnumber native fauna and flora. In many places they have left a distinctive biostratigraphic record of anthropogenic changes to the biosphere in the 20<sup>th</sup> century. Few ecosystems have been as severely affected by the arrival of neobiota as San Francisco Bay. Some 234 introduced species comprising up to 97% of individuals and in some places up to 99% of the biomass are known to be present in the bay (Cohen and Carlton, 1998). Among the multitude of neobiotic species established are <em>Trochammina hadai</em>, a benthic foraminifer that is native to Japan and was introduced in 1983 (McGann 2008), and <em>Potamocorbula amurensis</em>, a bivalved mollusc native to the Amur River region of East Asia that was introduced in 1986 (Carlton <em>et al</em>. 1990). Here we present sediment core data showing the arrival and proliferation of <em>T. hadai</em> and <em>P. amurensis</em> in addition to three introduced ostracod species, <em>Spinileberis quadriaculeata</em>, <em>Eusarsiella zostericola</em> and <em>Bicornucythere bisanensis</em>. The introduction of <em>T. hadai</em> is thought to have occurred through ballast water exchange from trans-Pacific shipping, and has produced a major perturbation to the foraminiferal record of San Francisco Bay. Pb-210 radiometric dating has established a high-resolution chronology for the core and analysis of fly ash particles (Rose 2015) emitted from coal-fired power stations allow time horizons, and the chronologies they define, to be correlated to a further 18 cores collected across the bay. This quantifies both the temporal and spatial extent of a human-induced biostratigraphic assemblage of neobiota, one that is correlatable with a biostratigraphic record of changes to ecosystems across the world in the late 20<sup>th</sup> century.</p><p> </p><p>Carlton, J.T., Thompson, J.K., Schemel, L.E. and Nichols, F.H. 1990. Remarkable invasion of San Francisco Bay (California, USA), by the Asian clam Potamocorbula amurensis. I. Introduction and dispersal. <em>Marine Ecology Progress Series</em>, 81-94.</p><p>Cohen, A.N. & Carlton, J.T. 1998. Accelerating invasion rate in a highly invaded estuary. <em>Science 279</em>, 555-558.</p><p>McGann, M. 2008. High-resolution foraminiferal, isotopic, and trace element record from Holocene estuarine deposits of San Francisco Bay, California. <em>Journal of Coastal Research 24</em>, 1092-1109.</p><p>Rose, N.L. 2015. Spheroidal carbonaceous fly ash particles provide a globally synchronous stratigraphic marker for the Anthropocene. <em>Environmental Science & Technology 49</em>, 4155-4162.</p>

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