TY - Generic T1 - Foraminifera ecology on the continental shelf, Merrimack Embayment, Gulf of Maine, New England T2 - Abstracts with Programs - Geological Society of America Y1 - 2010 A1 - Steven A Nathan A1 - Leckie, R. Mark A1 - Stephen B Mabee KW - #StaffPubs KW - applications KW - Atlantic Ocean KW - benthic taxa KW - Cenozoic KW - cluster analysis KW - deltaic environment KW - Economic geology, geology of nonmetal deposits 28A KW - Foraminifera KW - gravel deposits KW - Gulf of Maine KW - Invertebrata KW - Maine KW - marine environment KW - marine sediments KW - massachusetts KW - Merrimack River valley KW - microfossils KW - mining KW - North Atlantic KW - paleoecology KW - paleogeography KW - Pleistocene KW - Protista KW - Quaternary KW - Quaternary geology 24 KW - sand deposits KW - sea-level changes KW - sediments KW - shelf environment KW - species diversity KW - statistical analysis KW - United States KW - upper Pleistocene AB - During the late Pleistocene the Merrimack River paleodelta formed as post-glacial rebound produced a local low stand in sea level. Drowned as sea level rose, the paleodelta is now being reworked by a variety of processes. This study uses benthic foraminifera as a biotic and environmental proxy to study the sand and gravel resources of the paleodelta. Nineteen sediment samples were collected from the paleodelta along two east-west transects east of the Merrimack River. From these samples nearly 6000 benthic foraminifera, representing 62 species, were collected and identified. Although dissolution compromised the preservation of calcite tests within six samples, the resulting data is robust and allows for numerous conclusions to be drawn. Specifically, benthic foraminifera become more common distally and specific species inhabit specific areas of the paleodelta. Distribution patterns of some species have changed significantly since the late 1940s, with some species migrating landward, others, seaward. Distributions of some taxa differ significantly between the two transects, both in the present day and from the past. These differences may point to the influence of, and changes in, the Merrimack River outflow upon water column nutrient delivery, productivity and food availability over the past 60 years. Species diversity and evenness peak at the delta break, coincident with low species dominance at 50 meters water depth. Q-mode cluster analyses show three distinct assemblages, "shallow" (< or =30 meters water depth), "deep" (> or =40 meters), and "delta edge" (50 meters). There is no apparent correlation between foraminiferal distributions and deltaic bedforms, and in turn, sediment type. This implies that foraminiferal distributions are controlled by other environmental variables such as food. In summary, benthic foraminiferal assemblage analyses complement geophysical techniques. Benthic foraminifera can also help assess the marine impact of, e.g., mining sediment resources, watershed development, pollution, rising sea level, and increased fishing. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 42 SN - 00167592 UR - https://gsa.confex.com/gsa/2010NE/finalprogram/abstract_170108.htm IS - 11 N1 - Accession Number: 2010-092674; Conference Name: Geological Society of America, Northeastern Section, 45th annual meeting Geological Society of America, Southeastern Section, 59th annual meeting; Baltimore, MD, United States; Conference Date: 20100314; Language: English; Coordinates: N423000N430000W0703000W0705000; Coden: GAAPBC; Collation: 1; Collation: 82; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201049; Monograph Title: Geological Society of America, Northeastern Section, 45th annual meeting; Geological Society of America, Southeastern Section, 59th annual meeting; joint meeting, abstracts volume; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER -