Estimation of runoff distribution within river systems: Application to the Lena Basin (Siberia)

A channel account approach is proposed to estimate longitudinal changes in runoff along large river systems. This new method provides a quantitative basis for describing the fluvial transport of suspended particulate material and dissolved substances. This method includes an evaluation of basic elements of water balance in separate sections of the river network and subsequent correction of channel accounting equations for the entire system using a maximum likelihood principle. To calculate water discharges of tributaries that have no hydrological information, structural analysis of river network is performed. This approach provides less error in comparison with traditional methods of estimating lateral inflow. The method is used to trace water discharge with increasing distance along the Lena river basin and to evaluate the contribution of geologically and lithologically uneven sub-basins in water discharge formation during a summer low water period.     

Biostratigraphy of Jurassic-Cretaceous boundary sediments in the Eastern Crimea

The Dvuyakornaya Formation section in the eastern Crimea is described and subdivided into biostratigraphic units based on ammonites, foraminifers, and ostracodes. The lower part of the formation contains first discovered ammonites of the upper Kimmeridgian (Lingulaticears cf. procurvum (Ziegler), Pseudowaagenia gemmellariana Olóriz, Euvirgalithacoceras cf. tantalus (Herbich), Subplanites sp.) and Tithonian (?(Lingulaticeras efimovi (Rogov), Phylloceras consaguineum Gemmellaro, Oloriziceras cf. schneidi Tavera, and Paraulacosphinctes cf. transitorius (Oppel)). Based on the assemblage of characteristic ammonite species, the upper part of the formation is attributed to the Berriasian Jacobi Zone. Five biostratigraphic units (zones and beds with fauna) distinguished based on foraminifers are the Epistomina ventriosa-Melathrokerion eospirialis Beds and Anchispirocyclina lusitanica-Melathrokerion spirialis Zone in the upper Kimmeridgian-Tithonian, the Protopeneroplis ultragranulatus-Siphoninella antiqua, Frondicularia cuspidiata-Saracenaria inflanta zones, and Textularia crimica Beds in the Berriasian. The Cyrherelloidea tortuosa-Palaeocytheridea grossi Beds of the Upper Jurassic and Raymoorea peculiaris-Eucytherura ardescae-Protocythere revili Beds of the Berriasian are defined based on ostracodes. A new biostratigraphic scale is proposed for the upper Kimmeridgian-Berriasian of the eastern Crimea. The Dvyyakornaya Formation sediments are considered as deepwater facies accumulated on the continental slope.     

Hurricanes Frances and Jeanne remove blooms of the invasive green algaCaulerpa brachypus formaparvifolia (Harvey) cribb from coral reefs off Northern Palm Beach County, Florida

Coral reefs worldwide are under stress from a variety of anthropogenic activities that can alter or inhibit recovery from catastrophic physical disturbances such as hurricanes. On coral reefs off southeast Florida, land-based nutrient pollution contributed to a successful invasion ofCaulerpa brachypus fornaparvifolia that dominated (up to 90% cover) reefs between January 2003 and August 2004. In September 2004, physical effects from Hurricanes Frances and Jeanne removed virtually all of theC. brachypus from the affected reefs. In July 2005, small patches ofC. brachypus began to re-emerge and the area was affected again by Hurricane Wilma in October 2005. Although these hurricanes provided temporary relief from theC. brachypus invasion, the future of these reefs is uncertain because of competition with other opportunistic macroalgae and biota that may respond to the combination of newly created space and continued nutrient stress.