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dc.contributor.authorBenitez-Nelson, Claudia R.  Concept link
dc.coverage.spatialGulf of Maine
dc.date.accessioned2011-07-22T20:20:19Z
dc.date.available2011-07-22T20:20:19Z
dc.date.issued1998-09
dc.identifier.urihttps://hdl.handle.net/1912/4719
dc.descriptionSubmitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1998en_US
dc.description.abstractKnowledge of temporal and spatial nutrient turnover and export rates is of great importance for a variety of investigations, ranging from nutrient limitation to contamination uptake and removal. However, there are few methods that allow for the in situ elucidation of these processes. In this thesis research, in situ phosphorus turnover rates and upper ocean export were determined within the southwestern Gulf of Maine using the naturally occurring radionuclides phosphorus-32 (t_= 14.3 d), phosphorus-33 (t_ = 25.3 d), thorium-234 (t_ = 24.1) and beryllium-7 (t_ = 53.3 d). New techniques were developed for the extraction, purification and measurement of 32p and 33p in rainwater and in inorganic, organic and particulate pools in seawater. In order to constrain the input ratio of 33p/32p, rain samples were collected and measured continuously for 32p and 33p, as well as 7Be and 21OPb, from March 1996 to March 1998 at Woods Hole, MA, and from March 1997 to October 1997 at Portsmouth, NH. The average 33p;32p ratio was 0.88 ± 0.14. 32p, 33p, 7Be and 210Pb were further used to determine aerosol residence times and as possible tracers of stratospheric/tropospheric exchange during severe storm events. F our cruises were conducted in Wilkinson Basin, in the Gulf of Maine, during the spring and summer of 1997. 234Th was used to estimate advection and diffusion using 1D steady state and multi-dimensional non-steady state models. Export ratios (export/primary production) were found to range between 0.11 and 0.37. Vertical eddy diffusivity found using 7Be varied from 0.5 to 1.5 cm2 sec-I. Significant changes in phosphorus turnover rates within the reservoirs which contained 32p and 33p activity were found between the spring and summer months. In late summer, bacterial activity was substantial, significantly affecting the residence times of dissolved inorganic and organic phosphorus pools. Our results clearly show that 32p and 33p can provide much needed information regarding the biogeochemical cycling of P in marine systems and can be of use in the development of ecosystem models which seek to address mechanisms which affect primary production in the ocean.en_US
dc.description.sponsorshipFunding for this work was provided by the Office of Naval Research Fellowship Program, The Environmental Protection Agency Science to Achieve Results (STAR) Fellowship Program, the National Science Foundation (Grant no. OCE-9633240) and the Woods Hole Oceanographic Institution (unrestricted funds).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherMassachusetts Institute of Technology and Woods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Thesesen_US
dc.subjectPhosphorusen_US
dc.subjectCape Hatteras (Ship) Cruiseen_US
dc.titlePhosphorous cycling in the Gulf of Maine : a multi-tracer approachen_US
dc.typeThesisen_US
dc.identifier.doi10.1575/1912/4719


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