Refuge Update – March/April 2007, Volume 4, Number 2

Table of Contents: What’s Melting: Togiak Refuge Sizes Up Its Glaciers, page 3 Focus on Fish Conservation, pages 10-15 Whatever happened to…, pages 16-17 Wildlife Cooperatives, page 20

Refuge Update – July/August 2007, Volume 4, Number 4

Table of Contents: Counting Alpine Flora, page 3 Focus on Law Enforcement, pages 8–12 Virtual Geocaching, page 15 The Big Sit! at Your Refuge?, page 21

Refuge Update – November/December 2007, Volume 4, Number 6

Table of Contents: Celebrating 20 Years of Science on the M/ V Tiglax, page 5 Kevin Bell is honored as Captain of the largest ship operated by the National Wildlife Refuge System. Focus on…A River Runs Through It, pages 8-15 Rivers on refuges are managed for recreation, habitat restoration, water rights and sheer beauty. The Fight Against Giant Salvinia, page 18 Caddo Lake National Wildlife Refuge in Texas is fighting a weed that can travel three-quarters of a mile in 24 hours. Awards, page 21 From protecting the land to going “green,” awards recognize excellence.

High Resolution Paleoceanography of the Guaymas Basin, Gulf of California, During the Past 15 000 Years

Deep Sea Drilling Project Site 480 (27°54.10’N, 111°39.34’W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed on samples spaced every 40-50 yr, whereas ICP-AES geochemical analyses were completed on alternate samples (sample spacing 80-100 yr). The Bolling-Allerod interval (14.6-12.9 ka) (note, ka refers to 1000 calendar years BP throughout this report) is characterized by an increase in biogenic silica and a decline in calcium carbonate relative to surrounding intervals, suggesting conditions somewhat similar to those of today. The Younger Dryas event (12.9-11.6 ka) is marked by a major drop in biogenic silica and an increase in calcium carbonate. Increasing relative percentage contributions of Azpeitia nodulifera and Dictyocha perlaevis (a tropical diatom and silicoflagellate, respectively) and reduced numbers of the silicoflagellate Octactis pulchra are supportive of reduced upwelling of nutrient-rich waters. Between 10.6 and 10.0 ka, calcium carbonate and A. nodulifera abruptly decline at DSDP 480, while Roperia tesselata, a diatom indicative of winter upwelling in the modern-day Gulf, increases sharply in numbers. A nearly coincident increase in the silicoflagellate Dictyocha stapedia suggests that waters above DSDP 480 were more similar to the cooler and slightly more saline waters of the northern Gulf during much of the early and middle parts of the Holocene (~10 to 3.2 ka). At about 6.2 ka a stepwise increase in biogenic silica and the reappearance of the tropical diatom A. nodulifera marks a major change in oceanographic conditions in the Gulf. A winter shift to more northwesterly winds may have occurred at this time along with the onset of periodic northward excursions (El Nino-driven?) of the North Equatorial Countercurrent during the summer. Beginning between 2.8 and 2.4 ka, the amplitude of biogenic silica and wt% Fe, Al, and Ti (proxies of terrigenous input) increase, possibly reflecting intensification of ENSO cycles and the establishment of modern oceanographic conditions in the Gulf. Increased numbers of O. pulchra after 2.8 ka suggest enhanced spring upwelling.