Uncovering the Ediacaran phosphorus cycle.

Phosphorus is a limiting nutrient that is thought to control oceanic oxygen levels to a large extent1-3. A possible increase in marine phosphorus concentrations during the Ediacaran Period (about 635-539 million years ago) has been proposed as a driver for increasing oxygen levels4-6. However, little is known about the nature and evolution of phosphorus cycling during this time4. Here we use carbonate-associated phosphate (CAP) from six globally distributed sections to reconstruct oceanic phosphorus concentrations during a large negative carbon-isotope excursion-the Shuram excursion (SE)-which co-occurred with global oceanic oxygenation7-9. Our data suggest pulsed increases in oceanic phosphorus concentrations during the falling and rising limbs of the SE. Using a quantitative biogeochemical model, we propose that this observation could be explained by carbon dioxide and phosphorus release from marine organic-matter oxidation primarily by sulfate, with further phosphorus release from carbon-dioxide-driven weathering on land. Collectively, this may have resulted in elevated organic-pyrite burial and ocean oxygenation. Our CAP data also seem to suggest equivalent oceanic phosphorus concentrations under maximum and minimum extents of ocean anoxia across the SE. This observation may reflect decoupled phosphorus and ocean anoxia cycles, as opposed to their coupled nature in the modern ocean. Our findings point to external stimuli such as sulfate weathering rather than internal oceanic phosphorus-oxygen cycling alone as a possible control on oceanic oxygenation in the Ediacaran. In turn, this may help explain the prolonged rise of atmospheric oxygen levels.

Declining ambient water phosphorus concentrations in Massachusetts' rivers from 1999 to 2013: Environmental protection works.

Over the last century, nutrient concentrations in streams, rivers, lakes and ponds have increased substantially in the United States. Elevated phosphorus levels are a concern due to their ability to cause changes in freshwater ecosystems that are detrimental to humans and wildlife. In the present study, long-term trends in total phosphorus (TP) concentrations from 20 rivers in central Massachusetts from 1999 to 2013 were investigated. Kendall's correlation coefficients were used to demonstrate that 18 of the 20 rivers had significant reductions in TP concentrations (P < 0.05). A similar trend was found when flow-adjusted TP concentrations were analyzed. At the beginning of monitoring activities, the average TP concentration in 9 of the 20 rivers was greater than 0.05 mg/L and 6 of these 9 rivers contained TP concentrations greater than 0.1 mg/L; about fifteen years later, only 3 rivers contained TP greater than 0.05 mg/L and none had concentrations> 0.1 mg/L. TP decreases were greater in rivers with more anthropogenic inputs. Principal component analysis (PCA) revealed that the decline of TP in these Massachusetts streams is likely the result of advancements in wastewater treatment and implementation of effective non-point source management practices.

Evolution of the global phosphorus cycle.

The macronutrient phosphorus is thought to limit primary productivity in the oceans on geological timescales. Although there has been a sustained effort to reconstruct the dynamics of the phosphorus cycle over the past 3.5 billion years, it remains uncertain whether phosphorus limitation persisted throughout Earth's history and therefore whether the phosphorus cycle has consistently modulated biospheric productivity and ocean-atmosphere oxygen levels over time. Here we present a compilation of phosphorus abundances in marine sedimentary rocks spanning the past 3.5 billion years. We find evidence for relatively low authigenic phosphorus burial in shallow marine environments until about 800 to 700 million years ago. Our interpretation of the database leads us to propose that limited marginal phosphorus burial before that time was linked to phosphorus biolimitation, resulting in elemental stoichiometries in primary producers that diverged strongly from the Redfield ratio (the atomic ratio of carbon, nitrogen and phosphorus found in phytoplankton). We place our phosphorus record in a quantitative biogeochemical model framework and find that a combination of enhanced phosphorus scavenging in anoxic, iron-rich oceans and a nutrient-based bistability in atmospheric oxygen levels could have resulted in a stable low-oxygen world. The combination of these factors may explain the protracted oxygenation of Earth's surface over the last 3.5 billion years of Earth history. However, our analysis also suggests that a fundamental shift in the phosphorus cycle may have occurred during the late Proterozoic eon (between 800 and 635 million years ago), coincident with a previously inferred shift in marine redox states, severe perturbations to Earth's climate system, and the emergence of animals.

Between the utility and hazards of phosphorus through the centuries.

Phosphorus has been shown to be a predictor of cardiovascular mortality in kidney disease subjects. Phosphorus was discovered in 1669 and was considered a philosophers stone, it was used as medicament but there were reported deaths after its use. High serum levels of phosphorus are associated with increased risk for cardiovascular disease in the general population in subjects free from chronic kidney disease. Phosphorus can be defined as a useful and hazardous element for public health.

[Marie-Victor Ernest Baudrimont, a famous pharmacist from Compiègne, France]. / Marie-Victor Ernest Baudrimont, pharmacien compiégnois.

Ernest Baudrimont is a pharmacist born in Compiègne in 1821. He is the nephew of the pharmacist chemist Alexandre Baudrimont and is from a family of Compiègne pharmacists. First prize and gold medal in 1846 of the School of Pharmacy in Paris, he obtained in 1852 his Ph D in pharmacy for a dissertation on the formation and composition of mineral waters, and in 1864 is Ph D of physical sciences for a dissertation on the chlorides and bromides of phosphorus. Hospitals Chief Pharmacist in 1854, he had his first position at the Sainte Eugénie children's Hospital, today Trousseau hospital in Paris, position he held until 1875 prior to his appointment as Director of the Paris Civilian Hospitals central Pharmacy. Member of the french Botanical Society, the Society of Medical Hydrology, secretary of the Society of Pharmacy, he was also associate professor of Pharmacy at the School of Pharmacy of Paris. His scientific publications focus on the mineral chemistry i.e he described the nature of white phosphorus; mineral waters and some plants chemistry. One of the major contributions of Ernest Baudrimont was his involvment to the successive editions of the dictionary of the alterations and falsifications of foodstuffs of A. Chevallier. Member of the french Academy of Medicine in 1881, he died in Paris in September 1885.

Long-term variation (1960-2003) and causal factors of non-point-source nitrogen and phosphorus in the upper reach of the Yangtze River.

The knowledge of long-term variation and causal factors of non-point source (NPS) pollution in large-scale watersheds is helpful in the development of water quality control programs. In this study, the Improved Export Coefficient Model and the Revised Universal Soil Loss Equation were combined to estimate the temporal and spatial variations (1960-2003) of NPS pollution in the upper reach of the Yangtze River (URYR). Two change points for NPS pollution were successfully detected. In the URYR, the dissolved nitrogen (DN) and dissolved phosphorus (DP) increased before 2000 and decreased after 2000, whereas the inflection points from increase to decline were around 1980 for the adsorbed N (AN) and adsorbed P (AP). The results also indicated that the dissolved pollutants were mainly contributed by the anthropogenic factors, while the adsorbed pollutants were primarily exported by the natural factors. By comparing the load intensities from each source, it revealed that for the dissolved pollutants, the major source of the high load intensity transferred from urban land to dry land after 1980. Simultaneously, the high load intensity areas of the adsorbed pollutants transferred from forest to orchard around 1980, which was mainly attributed to the increasing fertilizer application. These results may be useful for planning and management of the URYR and other large-scale watersheds.

A brief history of phosphorus: from the philosopher's stone to nutrient recovery and reuse.

The element phosphorus has no substitute in sustaining all life and food production on our planet. Yet today's phosphorus use patterns have resulted in both a global environmental epidemic of eutrophication and led to a situation where the future availability of the world's main sources of phosphorus is uncertain. This paper examines the important history of human interference with the phosphorus cycle from initial discovery to present, highlighting key interrelated events and consequences of the Industrial Revolution, Sanitation Revolution and Green Revolution. Whilst these events led to profound advances in technology, public health and food production, they have fundamentally broken the global phosphorus cycle. It is clear a 'Fourth Revolution' is required to resolve this dilemma and ensure humanity can continue to feed itself into the future while protecting environmental and human health.

Phosphorus: the philosopher's stone discovered in 1669.

Recently the importance in nephrology of phosphorus as phosphate has been highlighted by chronic renal failure patients, in whom the toxic effect of phosphate is widely acknowledged, given the association of phosphate serum level with cardiovascular risk. This association is not limited to chronic renal failure and hemodialysis patients as high serum phosphate. Recently high serum phosphate levels were associated with increased risk for cardiovascular disease in subjects free from chronic kidney disease, and cardiovascular disease as well, and with progression of atherosclerosis. It is useful to know the history of phosphorus from its discovery in 1669, because that history gives us more evidence to better understand the negative and/or toxic effects of high phosphate serum levels and to identify phosphorus as a physiologically crucial anion.

Hot dog? Toxicological concerns and The Hound of the Baskervilles.

The terrifying dog in the Hound of the Baskervilles is described as having 'blazing eyes' and a 'luminous muzzle', appearances attributed by Watson and Holmes to the application of phosphorus. Review of the toxicity and flammability of white phosphorus make this improbable. It is suggested that Conan Doyle's description was probably influenced by knowledge of the recent and much publicized discovery of luminescence due to the radioactivity of uranium salts.

Recent sedimentary history of organic matter and nutrient accumulation in the Ohuira Lagoon, northwestern Mexico.

(210)Pb-derived sediment accumulation rates, as well as a suite of geochemical proxies (Al, Fe, delta(13)C, delta(15)N), were used to assess the time-dependent variations of C, N, and P fluxes recorded in two sediment cores collected at Ohuira Lagoon, in the Gulf of California, Mexico, during the last 100 years. Sedimentary C, N, and P concentrations increased with time and were related to land clearing, water impoundment, and agriculture practices, such as fertilization. C:N:P ratios and delta(13)C suggested an estuarine system that is responsive to increased C loading from a N-limited phytoplankton community, whereas delta(15)N values showed the transition between an estuarine-terrestrial to an estuarine-more marine environment, as a consequence of the declining freshwater supply into the estuary due to the channeling and impoundment of El Fuerte River between 1900 and 1956. The recent increases in nutrient fluxes (2- to 9-fold the pre-anthropogenic fluxes of C and N, and 2 to 13 times for P) taking place in the mainland from the 1940s, were related to the expansion of the intensive agriculture fields and to the more recent development of shrimp farming activities.

Historical eutrophication in a river-estuary complex in mid-coast Maine.

European settlement of New England brought about a novel disturbance regime that impacted rivers and estuaries through overfishing, deforestation, dams, and water pollution. The negative consequences of these activities intensified with industrialization in the 19th and 20th centuries, often resulting in ecosystem degradation. Since environmental legislation was implemented in the 1970s, improvement in water quality has been tangible and widespread; however, ecological recovery can require substantial amounts of time and may never be complete. To document the natural baseline conditions and investigate the recovery of a severely degraded river-estuary complex in mid-coast Maine, we examined diatoms, pollen, total organic carbon, total nitrogen, stable isotopes, total phosphorus, biogenic silica, and trace metals in intertidal sediments and established a chronology with 14C, 210Pb, and indicator pollen horizons. Both climate variability and human effects were evident in the sedimentary record of Merrymeeting Bay, the freshwater tidal portion of the Kennebec estuary. Natural climate variability was apparent in an episode of high sedimentation and altered diatom abundance during the 12th and 13th centuries and in changing pollen abundances between the 16th and 19th centuries, indicative of regional cooling. During the 18th century, colonial land clearance began an era of high sedimentation and eutrophication that strongly intensified with industrialization during the late 19th and 20th centuries. Improvements in water quality over the past 30 years in response to environmental regulation had little effect on ecosystem recovery as represented by the sedimentary record. Diatom composition and productivity and high fluxes of organic C, total P, and biogenic Si in recent sediments indicate that rates of nutrient loading remain high. These environmental proxies imply that aquatic productivity in Merrymeeting Bay was originally nutrient limited and water clarity high, relative to today. Further recovery may require more stringent regulation of nutrient inputs from industrial and municipal point sources. This historical study can contribute to public debate about the environmental management of this unusual river-estuary complex by describing its long-term natural baseline, thereby illustrating the upper limit of its potential for recovery.

Bioavailability of slowly cycling soil phosphorus: major restructuring of soil P fractions over four decades in an aggrading forest.

Although low solubility and slow cycling control P circulation in a wide range of ecosystems, most studies that evaluate bioavailability of soil P use only indices of short-term supply. The objective here is to quantify changes in P fractions in an Ultisol during the growth of an old-field pine forest from 1957 to 2005, specifically changes with organic P (Po) and with inorganic P (Pi) associated with Fe and Al oxides as well as Ca compounds. Changes in soil P were estimated from archived mineral soil samples collected in 1962 shortly after pine seedlings were planted, and on six subsequent occasions (1968, 1977, 1982, 1990, 1997, and 2005) from eight permanent plots and four mineral soil layers (0-7.5, 7.5-15, 15-35, and 35-60 cm). Despite the net transfer of 82.5 kg ha(-1) of P from mineral soil into tree biomass and O horizons, labile soil P was not diminished, as indexed by anion exchange resins, and NaHCO(3) and Mehlich III extractants. An absence of depletion in most labile P fractions masks major restructuring of soil P chemistry driven by ecosystem development. During 28 years of forest growth, decreases were significant and substantial in slowly cycling Po and Pi associated with Fe and Al oxides and Ca compounds, and these accounted for most of the P supplied to biomass and O horizons, and for buffering labile soil fractions as well. Changes in soil P are attributed to the P sink strength of the aggrading forest (at 2.9 kg ha(-1) year(-1) over 28 years); legacies of fertilization, which enriched slowly cycling fractions of Po and Pi; and the changing biogeochemistry of the soil itself.

Spatial and historical variation in sediment phosphorus fractions and mobility in a shallow lake.

Temporal and spatial variation in sediment P composition and mobility were investigated in Loch Leven. Little change was observed in total sediment P (surface sediment at 4m depth), in comparison to a previous study (1990), despite significant reduction of external point sources of P. Labile P and residual P have both increased (0.007-0.039 mg PO(4)-P and 0.121-0.420 mg PO(4)-P per gram dry weight of sediment, respectively) since 1990. An analysis of P fractions, along a depth transect, indicated elevated labile P concentrations in shallow water sediment (<12 m overlying water depth). Regression analysis showed that spatial variability in reductant-adsorbed P was significantly related to sediment chlorophyll a concentration (R(2)=0.733, p<0.05). This may be linked to the production of oxygen, by benthic algae, resulting in the maintenance of an oxygenated layer at the sediment surface. Variation in labile P was best explained by overlying water temperature and equilibrium phosphate concentration (EPC0).

Effects of historical lake level and land use on sediment and phosphorus accumulation rates in Lake Kinneret.

Current paradigms of reservoir ontogeny suggest that water-level fluctuations may increase sedimentary nutrient release, causing long-term eutrophication of water bodies formed by dryland flooding. Less is known of the changes in nutrient status following conversion of natural lakes into reservoirs. Here, we use historical hydrological and limnological data and paleolimnological records of sedimentary P accumulation to evaluate changes in nutrient storage in Lake Kinneret, Israel since approximately 1860. Impoundment in 1932 increased water level fluctuations and altered seasonal hydrologic patterns in the lake. Geochemical analysis of sediment deposits indicated that bulk sediment and P accumulation rates in the central lake increased >600% following dam installation (1930s), draining of Lake Hula wetlands (1951-1957), and diversion of surface water outflow (1964 to present). Further, comparison of sedimentary P stratigraphies with long-term chemical records showed that the period of maximum P deposition corresponds to observed increases in whole-lake and in hypolimnetic P content, as well as epilimnetic biological changes indicative of ongoing eutrophication. Together, these patterns suggest that hydrologic management of natural lakes can increase sedimentary nutrient flux under circumstances where lake volume and water levels become more variable.

Effect of water quality management efforts on wastewater loadings during the past century.

The history of wastewater discharges to the Hudson River watershed from Troy, New York, to the New York City Harbor was traced from 1900 to 2000. The parameters studied include population, flow, type of treatment, biochemical oxygen demand, suspended solids, total nitrogen, and total phosphorus. This paper details a methodology for estimating historic loadings where data are lacking. The data show dramatic changes in wastewater loadings. There has been a continued increase in wastewater flow and population over the past century but a decrease in contaminant loading during the last 25 years. The reduction in effluent loads is directly related to state and federal water quality management programs and the substantial public and private investment made in upgrading point source water pollution control infrastructure. A comparison of point with nonpoint source loads shows that although nonpoint sources are now a significant contributor of contaminants to the river, point sources remain as major sources of total nitrogen and total phosphorus.

Decadal change in vegetation and soil phosphorus pattern across the Everglades landscape.

Wetlands respond to nutrient enrichment with characteristic increases in soil nutrients and shifts in plant community composition. These responses to eutrophication tend to be more rapid and longer lasting in oligotrophic systems. In this study, we documented changes associated with water quality from 1989 to 1999 in oligotrophic Everglades wetlands. We accomplished this by resampling soils and macrophytes along four transects in 1999 that were originally sampled in 1989. In addition to documenting soil phosphorus (P) levels and decadal changes in plant species composition at the same sites, we report macrophyte tissue nutrient and biomass data from 1999 for future temporal comparisons. Water quality improved throughout much of the Everglades in the 1990s. In spite of this improvement, though, we found that water quality impacts worsened during this time in areas of the northern Everglades (western Loxahatchee National Wildlife Refuge [NWR] and Water Conservation Area [WCA] 2A). Zones of high soil P (exceeding 700 mg P kg(-1) dry wt. soil) increased to more than 1 km from the western margin canal into the Loxahatchee NWR and more than 4 km from northern boundary canal into WCA-2A. This doubling of the high soil P zones since 1989 was paralleled with an expansion of cattail (Typha spp.)-dominated marsh in both regions. Macrophyte species richness declined in both areas from 1989 to 1999 (27% in the Loxahatchee NWR and 33% in WCA-2A). In contrast, areas well south of the Everglades Agricultural Area, induding WCA-3A and Everglades National Park (ENP), did not decline during this time. We found no significant decadal change in plant community patterns from 1989 and 1999 along transects in southern WCA-3A or Shark River Slough (ENP). Our 1999 sampling also included a new transect in Taylor Slough (ENP), which will allow change analysis here in the future. Regular sampling of these transects, to verify decadal-scale environmental impacts or improvements, will continue to be an important tool for long-term management and restoration of the Everglades.