ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    Electronic Resource
    Electronic Resource
    Solute export from forested and partially deforested chatchments in the central Amazon (1997)
    Springer
    Biogeochemistry 38 (1997), S. 67-102 
    Details
    ISSN: 1573-515X
    Keywords: Amazon ; catchments ; deforestation ; slash-and-burn agriculture ; solutes ; water balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The hydrochemical responses to slash-and-burnagriculture in a small rainforest catchment of thecentral Amazon were investigated for one year. Disturbances in the partially deforested catchmentbegan in 1987, and during the study a 2-ha plot was cut(July 1989) and burned (October 1989) in preparationfor the cultivation of manioc; the partially deforestedcatchment was approximately 80% deforested at the timeof this study. Solute fluxes exported by base flowwere estimated from solute concentrations of stream watermeasured at least once per week. Solute fluxesfor storm flow were estimated by measuring streamwaterconcentrations during two storms. Baseflow runoffrepresented about 94% of the water outflow from thestudy basin and was the dominant pathway of soluteexport. Total rainfall during the study period was2754 mm of which 2080 mm was exported from thepartially deforested catchment as stream runoff. Theratio of surface runoff to annual rainfall for asimilar study conducted in the same catchment whilecompletely forested in 1984 was lower than after thecatchment was 80% deforested in 1990 (0.57 versus0.76), while evapotranspiration (ET) was lower by about afactor of two in 1990 compared to 1984. Particulateremoval from the partially deforested catchment was 151kg ha−1 yr−1. Nutrient losses from thepartially deforested catchment were higher than thosemeasured when the catchment was undisturbed in 1984 byfactors of 1.4, 1.8, and 2.1 for total inorganicnitrogen (TIN), total dissolved nitrogen (TDN), and totalnitrogen (TN); and by factors of 4.0, 6.6, and 7.9 for solublereactive phosphate (PO3− 4), total dissolvedphosphorus (TDP), and total phosphorus (TP),respectively. These data show that deforestation andcolonization in upland catchments of the central Amazonalter the hydrochemical balance of streams bydecreasing ET, thereby increasing discharge and soluteexport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005774431820
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    7. Photosynthetic activity of phytoplankton in tropical African soda lakes (1981)
    Springer
    Hydrobiologia 81-82 (1981), S. 71-85 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Mass balance of major solutes in a rainforest catchment in the Central Amazon: Implications for nutrient budgets in tropical rainforests (1996)
    Springer
    Biogeochemistry 32 (1996), S. 115-142 
    Details
    ISSN: 1573-515X
    Keywords: Central Amazon ; nutrient budgets ; tropical rainforests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A solute mass balance for a 23.4 ha catchment of undisturbed rainforest in the central Amazon Basin was computed from detailed measurements of water and solute fluxes via rainfall, streamflow, and subsurface outflow over an annual cycle. Annual atmospheric deposition fluxes are lower than previously reported among mass balance studies conducted in the Amazon. Nutrient export fluxes are lower than previously reported for the Amazon, despite the fact that export fluxes via flow paths not previously measured were included. Given that climatic conditions were representative of a one in 10 wet year, the ecosystem was expected to show a net loss of nutrients rather than net gain. Instead, an excess of nutrient inputs via rainfall over ecosystem outflows was detected, ranging in annual quantities from 0.30 to 0.50 of the measured input. Among several mechanisms that could reconcile this budget, two are supported by the information presently available while two others cannot be evaluated without further research. Interannual variability in the amount of water available for runoff at the spatial scale of small catchments varies by a factor of two, in contrast to rainfall variability of ±20%, and may be a critical control on the apparent changes in ecosystem storage detected by annual-scale nutrient budgets in rainforests. Entrainment of materials from the terrestrial ecosystem to the atmosphere, including particulates containing elements which do not exist as gases, may be a particularly important loss pathway in rainforests existing on deeply weathered or nutrient poor soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000355
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Atmospheric deposition, mass balances, and processes regulating streamwater solute concentrations in mixed-conifer catchments of the Sierra Nevada, California (1997)
    Springer
    Biogeochemistry 37 (1997), S. 111-144 
    Details
    ISSN: 1573-515X
    Keywords: California ; catchments ; discharge-concentration relationships ; mass balances ; wet deposition ; Sierra Nevada
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Solute concentrations in atmospheric deposition and stream water were measuredfrom 1984 through 1993 to determine the fate and mobility of solutes in twogauged mixed-conifer catchments (Tharp's and Log creeks) located in theSierra Nevada, California. The two catchments contain mature forest standsdominated by Abies concolor (white fir), Sequoiadendron giganteum (giantsequoia), Abies magnifica (red fir) and Pinus lambertiana (sugar pine).Ammonium, Cl-, Ca2+ and NO- 3were highest in concentration of the solutes measured in wet deposition;bulk deposition was highest in SO2- 4, NH+ 4,Cl- and H+. Net retention ofH+, NO3 -, NH4 +,SO4 2- and Cl- occurred in both catchments.Discharge was dominated by spring snowmelt with the largest export yieldsfor acid neutralizing capacity (ANC), SiO2, andCa2+. Export yields of H+,NO3 -, NH4 + and PO4 3-were relatively small (0.5 kg ha-1 y-1).Discharge-concentration relationships for ANC, SiO2,Na+, K+, Ca2+ andMg2+ were inverse and their concentrations in stream waterwere primarily influenced by discharge and annual differences in the relativecontributions of snowmelt and groundwater. The mobility of these solutes iscontrolled by the rates of mineral weathering and ion exchange. The positiverelationship of SO4 2- concentration with increasingdischarge suggests that atmospherically deposited SO4 2-is temporarily stored and that its release is controlled by the extent of soilwater flushing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005705927291
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Effects of prescribed burning and drought on the solute chemistry of mixed-conifer forest streams of the Sierra Nevada, California (1997)
    Springer
    Biogeochemistry 39 (1997), S. 225-253 
    Details
    ISSN: 1573-515X
    Keywords: California ; catchments ; drought ; mass balances ; prescribed burning ; solutes ; Sierra Nevada ; stream water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Solute concentrations in atmospheric depositionand stream water were measured in two mixed-conifercatchments (Tharp‘s and Log creeks) in the SierraNevada of California from 1984 through 1995, a periodincluding a 6-year drought and a prescribed burn inone catchment. The effects of prescribed burning inthe Tharp‘s Creek catchment significantly increasedthe concentrations of most solutes in stream water. In the first year after prescribed burning, the VWM(volume-weighted mean) concentrations of acid anionsin stream water increased proportionally more thanthose of the base cations, and ANC (acid neutralizingcapacity) more than doubled. Sulfate and NO 3 - increased proportionally more in streamwater than any other ions after the fire, but pre- andpost-burn VWM pH were not significantlydifferent. VWM SO 4 2- and NO 3 - concentrations the first year after burning occurredwere about 16- and 2,000-fold above pre-burnbaselines, respectively, while that of Cl-increased 4-fold. Net retention (precipitationinputs minus streamwater outputs) of H+,NO 3 - , NH 3 + , SO 4 2- and Cl- occurred in both catchments, except afterprescribed burning of the Tharp’s Creek catchment inthe fall of 1990, which caused a net export ofSO 4 2- , Cl- and K+ thefirst year after the burn. Most solutes remained abovepre-disturbance concentrations by the end of the thirdyear after burning, whereas H+ and SiO2remained below. Periodic increases in theconcentrations of Na+, Ca2+ and SO 4 2- , and decreases in ANC and SiO2occurred during a 6-year drought monitored in theadjacent undisturbed catchment of Log Creek.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005858219050
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Composition and deposition of throughfall in a flooded forest archipelago (Negro River, Brazil) (1999)
    Springer
    Biogeochemistry 45 (1999), S. 169-195 
    Details
    ISSN: 1573-515X
    Keywords: Amazon ; flooded forest ; Negro River ; rain ; solutes ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The sources of spatial and temporal variation and rates of nutrient deposition via throughfall were studied for 9 months in the Anavilhanas archipelago of the Negro River, Brazil. A total of 30 events was sampled individually for rain and throughfall chemistry in a 1-ha plot of flooded forest. Throughfall samples were collected in 40 collectors distributed in five parallel transects in the study plot, while rain was collected in 4 collectors in an adjacent channel. Volume-weighted mean (VWM) concentrations of solutes in rain were consistently lower than in throughfall, except for H+, NO 3 − and NH 4 + . Ratios of VWM concentrations of rain to throughfall indicated that K+, followed by Mg2+ and PO 4 3− , were the most enhanced solutes as rain passed through the forest canopy. The deposition of solutes varied significantly among transects, except for Na+ and Ca2+, and was significantly correlated with maximum flooding depth, foliar nutrient content, soil fertility and canopy closure for most solutes. The concentrations of PO 4 3− and most major ions were higher in throughfall compared to those in rain due to canopy exchange and dry deposition. In contrast, NO 3 − , NH 4 + and H+ were retained due to immobilization by leafy canopy and ion exchange processes. Solute inputs via throughfall (not including stemflow) to a floodplain lake (Lake Prato) of the archipelago accounted for 30 to 64% of the total for most solutes in the lake at high water, which indicates that throughfall is an important source of nutrients to the aquatic ecosystem of the Anavilhanas archipelago.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01106780
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Fluxes and transformations of nitrogen in a high-elevation catchment, Sierra Nevada (1995)
    Springer
    Biogeochemistry 28 (1995), S. 1-31 
    Details
    ISSN: 1573-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The fluxes and transformations of nitrogen (N) were investigated from 1985 through 1987 at the Emerald Lake watershed (ELW), a 120 ha high-elevation catchment located in the southern Sierra Nevada, California, USA. Up to 90% of annual wet deposition of N was stored in the seasonal snowpack; NO 3 − and NH 4 + were released from storage in the form of an ionic pulse, where the first fraction of meltwater draining from the snowpack had concentrations of NO 3 − and NH 4 + as high as 28 μeq L−1 compared to bulk concentrations of 〈5 μeq L−1 in the snowpack. The soil reservoir of organic N (81 keq ha−1) was about ten times the N storage in litter and biomass (12 keq ha−1). Assimilation of N by vegetation was balanced by the release of N from soil mineralization, nitrification, and litter decay. Mineralization and nitrification processes produced 1.1 keq ha−1 yr−1 of inorganic N, about 3 1/2 times the loading of N from wet and dry deposition. Less than 1% of the NH 4 + in wet and dry deposition was exported from the basin as NH 4 + . Biological assimilation was primarily responsible for retention of NH 4 + in the basin, releasing one mode of H+ for every mole of NH 4 + retained and neutralizing about 25% of the annual acid neutralizing capacity produced by mineral weathering in the basin. Nitrate concentrations in stream waters reached an annual peak during the first part of snowmelt runoff, with maximum concentrations in stream water of 20 μeq L−1, more than 4 times the volume-weighted mean annual concentrations of NO 3 − in wet deposition. This annual peak in stream water NO 3 − was consistent with the release of NO 3 − from the snowpack in the form of an ionic pulse; however soil processes occurring underneath the winter snowpack were another potential source of this NO 3 − . Concentrations of stream water NO 3 − during the summer growing season were always near or below detection limits (0.5 μeq L−1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02178059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Atmospheric deposition and solute export in giant sequoia — mixed conifer watersheds in the Sierra Nevada, California (1991)
    Springer
    Biogeochemistry 12 (1991), S. 207-230 
    Details
    ISSN: 1573-515X
    Keywords: atmospheric deposition ; coniferous watershed ; forest ecosystem ; solute export ; stream discharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Atmospheric depostion and stream discharge and solutes were measured for three years (September 1984 — August 1987) in two mixed conifer watersheds in Sequoia National Park, in the southern Sierra Nevada of California. The Log Creek watershed (50 ha, 2067–2397 m elev.) is drained by a perennial stream, while Tharp's Creek watershed (13 ha, 2067–2255 m elev.) contains an intermittent stream. Dominant trees in the area include Abies concolor (white fir), Sequoiadendron giganteum (giant sequoia), A. magnifica (red fir), and Pinus lambertiana (sugar pine). Bedrock is predominantly granite and granodiorite, and the soils are mostly Pachic Xerumbrepts. Over the three year period, sulfate (SO4 2−), nitrate (NO3 −), and chloride (Cl−1) were the major anions in bulk precipitation with volume-weighted average concentrations of 12.6, 12.3 and 10.0 μeq/1, respectively. Annual inputs of NO3-N, NH4-N and SO4-S from wet deposition were about 60 to 75% of those reported from bulk deposition collectors. Discharge from the two watersheds occurs primarily during spring snowmelt. Solute exports from Log and Tharp's Creeks were dominated by HCO3 −, Ca2+ and Na+, while H+, NO3 −, NH4 + and PO4 3− outputs were relatively small. Solute concentrations were weakly correlated with instantaneous stream flow for all solutes (r2 〈0.2) except HCO3 − (Log Cr. r2 = 0.72; Tharp's Cr. r2 = 0.38), Na+ (Log Cr. r2 = 0.56; Tharp's Cr. r2 = 0.47), and silicate (Log Cr. r2 = 0.71; Tharp's Cr. r2 = 0.49). Mean annual atmospheric contributions of NO3-N (1.6 kg ha−1), NH4-N (1.7 kg ha−1), and SO4-S (1.8 kg ha−1), which are associated with acidic deposition, greatly exceed hydrologic losses. Annual watershed yields (expressed as eq ha−1) of HCO3 − exceeded by factors of 2.5 to 37 the annual atmospheric deposition of H+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00002608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Nitrogen yields from undisturbed watersheds in the Americas (1999)
    Springer
    Biogeochemistry 46 (1999), S. 149-162 
    Details
    ISSN: 1573-515X
    Keywords: dissolved organic nitrogen ; nitrogen concentrations ; nitrogen cycle ; nitrogen yields ; nitrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Yields of total fixed nitrogen and nitrogen fractions are summarized for thirty-one watersheds in which anthropogenic disturbance of the nitrogen cycle, either through land use or atmospheric deposition, is negligible or slight. These yields are taken as representative of background conditions over a broad range of watershed areas, elevations, and vegetation types. The data set focuses on watersheds of the American tropics, but also includes information on the Gambia River (Africa) and some small watersheds in the Sierra Nevada of California. For the tropical watersheds, total nitrogen yield averages 5.1 kg ha −1 y−1. On average, 30% of the total is particulate and 70% is dissolved. Of the dissolved fraction, an average of 50% is organic and 50% is inorganic, of which 20% is ammonium and 80% is nitrate. Yields are substantially lower than previously estimated for background conditions. Yields of all nitrogen fractions are strongly related to runoff, which also explains a large percentage of variance in yield of total nitrogen (r2 = 0.85). For total nitrogen and nitrogen fractions, yield increases at about two-thirds the rate of runoff; concentration decreases as runoff increases. There is a secondary but significant positive relationship between elevation and yield of DIN. Ratios DON/TDN and PN/TN both are related to watershed area rather than runoff; DON/TDN decreases and PN/TN increases toward higher stream orders. The analysis suggests for tropical watersheds the existence of mechanisms promoting strong homeostasis in the yield of N and its fractions for a given moisture regime, as well as predictable downstream change in proportionate representation N fractions. Yields and concentrations for small tropical watersheds are much larger than for the few temperate ones with which comparisons are possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006108315578
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Photosynthetic activity of phytoplankton and its relation to environmental factors in hypersaline Mono Lake, California (1988)
    Springer
    Hydrobiologia 158 (1988), S. 69-88 
    Details
    ISSN: 1573-5117
    Keywords: Mono Lake ; photosynthesis ; salt lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic activity of phytoplankton in hypersaline Mono Lake, California was measured over the three year period, 1983–1985. The maximum chlorophyll-specific rate of carbon uptake (Pm B) and the light-limited slope (alpha) were derived from laboratory measurements of photosynthesis vs. irradiance (P-I) relationships. Annual estimates of primary production were 340–540 g C m-2 yr-1. Production was two to three times higher during the spring of 1983 than in the springs of 1984 and 1985; higher standing biomass of algae occurred in 1983. While Pm B rates followed water temperatures and varied over 40-fold over the year, integral primary production varied less since periods of high Pm B occurred when algal biomass was low. Sixty-eight percent of the seasonal variation in the Pm B was explained by a regression on temperature (53%), chlorophyll a (12%), and the carbon:chlorophyll a ratio (3%). Light-saturated and light-limited rates of photosynthesis generally covaried, evidenced by the strong seasonal correlation between Pm B and alpha. Sixty-one percent of variation in alpha was explained by a regression on Pm B, temperature, grazing, water column stability, and self-shading. There was no correlation of carbon uptake with ambient levels of inorganic nitrogen. The regression coefficient of the dependence of Pm B on the seasonal temperature trend was much larger than that determined from individual samples incubated at several different temperatures; this indicates that uptake is limited by more than low temperatures in the spring. Regression equations including only temperature, chlorophyll and depth were sufficient to estimate patterns of seasonal and year to year variation in integral primary productivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00026267
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...