Transformation of Laguna Lake from a marine arm of Manila Bay to a freshwater system

Abstract only.Evolution of Laguna Lake during the past 6,000 years is established using paleontologic, sedimentologic, and geochemical profiles of a 10.5-meter long sediment core from the western lobe. Marine molluscan and diatom assemblages reveal a lagoonal environment with depths initially greater than 10 m, 5,700 radiocarbon years ago (yBP), then it consistently shallowed to intertidal depths until 3,700 yBP. Tellina sp., Leptaxinus sp., and Anomalocardia sp. predominated the molluscan fauna. The marine Cyclotella stylorum, Thalassiosira eccentrica, and Thalassiosira lineata, comprise 80% of the diatom fauna. Brackish water condition was short-lived and it was succeeded by freshwater conditions set at the appearance of Vivipara burroughiana 3,000 yBP. The XRF-derived sulfur, strontium, and calcium concentrations and their aluminum-normalized trends used as geochemical proxy records, corroborate the changing salinity levels and the age boundaries set from the molluscs. Lowering of sea level from the mid Holocene high and vertical movements across the West Marikina Valley Fault, which presently bound the western edge of Laguna Lake, led to the emergence of the Muntinlupa-Paranaque stretch, isolating the proto-Laguna Lake from Manila Bay. Pulsed decreases of salinity to freshwater levels at 250-year intervals and the associated emergence of a 30 m-high barrier reveal a large tectonic influence as opposed to small climatic and sea level shifts within this period. In the last few decades, a new phase of environmental shift has been occurring in the lake. Global warming and land subsidence elevated the saltwater backflow into the lake, enough to leave an increasing salinity trend in the sediment record

Complete genome sequence of universal bacteriophage host strain Campylobacter jejuni subsp. jejuni PT14

Campylobacter jejuni strain PT14 is a clinical isolate previously used to propagate bacteriophages in the United Kingdom phage typing scheme. The strain has proven useful in the isolation of Campylobacter bacteriophages from several sources, and it functions as a model host in phage therapy experiments with poultry and poultry meat

Micropaleontology of the 2013 Typhoon Haiyan Overwash Sediments from the Leyte Gulf, Philippines

Coastal geologic records allow for the assessment of long-term patterns of tropical cyclone variability. However, the accuracy of geologic reconstructions of tropical cyclones is limited by the lack of modern analogues. We describe the microfossil (foraminifera and testate amoebae) assemblages contained within overwash sediments deposited by Typhoon Haiyan when it made landfall on the islands of Leyte and Samar in the Philippines on 7 November 2013 as a Category 5 super typhoon. The overwash sediments were transported up to 1.7 km inland at four study sites. The sediments consisted of light brown medium sand in a layer \u3c1 to 8 cm thick. We used Partitioning Around a Medoid (PAM) cluster analysis to identify lateral and vertical changes in the foraminiferal and testate amoebae data. The presence of intertidal and subtidal benthic, and planktic foraminifera that were variably unaltered and abraded identify the microfossil signature of the overwash sediments. Agglutinated mangrove foraminifera and testate amoebae were present within the overwash sediments at many locations and indicate terrestrial scouring by Haiyan\u27s storm surge. PAM cluster analysis subdivided the Haiyan microfossil dataset into two assemblages based on depositional environment: (1) a low-energy mixed-carbonate tidal flat located on Samar Island (Basey transect); and (2) a higher-energy clastic coastline near Tanauan on Leyte Island (Santa Cruz, Solano, and Magay transects). The assemblages and the taphonomy suggest a mixed provenance, including intertidal and subtidal sources, as well as a contribution of sediment sourced from deeper water and terrestrial environments. (C) 2016 Elsevier B.V. All rights reserved

Diploastrea heliopora Sr/Ca and δ18O records from northeast Luzon, Philippines : an assessment of interspecies coral proxy calibrations and climate controls of sea surface temperature and salinity

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography 32 (2017): 424–438, doi:10.1002/2017PA003098.The Indo-Pacific coral Diploastrea heliopora reveals regional multidecadal- to centennial- scale climate variability using coral carbonate δ18O (δ18Oc) as a combined proxy for sea surface temperature (SST) and sea surface salinity (SSS). However, to assess the coral's full potential in resolving climatic events, an independent SST proxy would be more advantageous. We examined both Sr/Ca and δ18O of Diploastrea against an adjacent Porites lobata core collected from northeast Luzon, Philippines. Winter Sr/Ca data from Diploastrea show a significant correlation to SST (r = −0.41, p < 0.05, (root-mean-square of the residual) RMSR = 0.81°C) and provide a proxy with similar sensitivity as Porites (r = −0.57, p < 0.05, RMSR = 0.62°C). An interspecies SST record is shown to be robust and used for a reconstruction of the Pacific Decadal Oscillation during boreal winter (r = −0.70, p = 0.02). While we were unable to generate a robust Diploastrea δ18O-SSS calibration at interannual timescale, the freshening trend toward the present, commonly observed in the region, is qualitatively captured in Diploastrea δ18O. Comparison with Porites δ18O and instrumental SSS records shows that the magnitude of freshening is consistent between coral species. Wet and dry season Porites δ18O provide support for the relative influence of El Niño–Southern Oscillation events and local precipitation to SSS variability at our site. The multiproxy, multispecies approach of this study further strengthens the evidence for Diploastrea as an alternate climate archive in the Indo-Pacific region and seals its potential in helping resolve less understood global-scale climate phenomena.National Research Foundation Singapore (NRF) Grant Number: NRF-RF2012-0

Indicators and possible driving mechanisms of shifts in the position of Agusan river along the Butuan coastal plain

The Butuan coastal plain is a fan-delta formed by deposition of Agusan River sediments in the past 7,400 radiocarbon years (ky). Traces of paleochannels that scar the coastal plain, seen in satellite images, indicate past river positions. Immediately prior to the present, Masao River was the active distributary as suggested by its well-defined and still continuous paleochannel. Numerous sudden shifts of river position have likely originated in the San Vicente area, the apex region of the fan-delta. These shifts could have been self driven or induced by floods or tectonics. Sediment input from rivers along the eastern flank of the Butuan coastal plain forced a number of downstream shifts. The function of the Agusan Marsh in buffering flashy river discharges in the Butuan coastal plain is threatened by present-day elevated sediment loads of rivers upstream

Five thousand years of environmental history: Paoay Lake, northern Luzon, Philippines

The environmental history of Paoay Lake and its surrounding landscape is being examined through the analysis of pollen, diatoms, charcoal, mineral magnetics, and AMS dating. The project is part of a larger program of archeological research that examines the theory indicating an expansion of Neolithic people taking place out of Taiwan and into island southeast Asia around 4,000 years ago. The primary intention of the lake study is to determine if there is evidence of land clearance and agricultural development in the region during the late Holocene. Sediment cores collected from two different locations contain the last 6,000 years of environmental history at Lake Paoay. Pollen analysis shows that coniferous forest, dominated by Pinus, was prevalent in the landscape surrounding the site until around 5,000 years ago when the pollen signature changes to that more indicative of an open landscape (primarily grass). Charcoal as an indicator of fire is abundant throughout record, although the highest levels appear to occur around the time of forest decline. This corresponds well with a similar shift in vegetation at 5,000 years ago from the only other pollen core in the Philippines, Laguna de Bay