Estimating soilpCO2using paleosol carbonates: implications for the relationship between primary productivity and faunal richness in ancient terrestrial ecosystems

Paleobiology ◽  
2012 ◽  
Vol 38 (4) ◽  
pp. 585-604 ◽  
Author(s):  
Timothy S. Myers ◽  
Neil J. Tabor ◽  
Louis L. Jacobs ◽  
Octávio Mateus
Keyword(s):  
Organic Matter ◽  
Primary Productivity ◽  
Western Europe ◽  
Central Africa ◽  
Terrestrial Ecosystems ◽  
Upper Jurassic ◽  
Morrison Formation ◽  
Positive Correlation ◽  
Terrestrial Environments ◽  
Ancient Ecosystems

In this paper we present a method for estimating soilpCO2in ancient environments using the measured carbon-isotope values of pedogenic carbonates and plant-derived organic matter. The validity of soilpCO2estimates proves to be highly dependent on the organic δ13C values used in the calculations. Organic matter should be sourced from the same paleosol profiles as sampled carbonates to yield the most reliable estimates of soilpCO2. In order to demonstrate the potential use of soilpCO2estimates in paleoecological and paleoenvironmental studies, we compare samples from three Upper Jurassic localities. SoilpCO2estimates, interpreted as a qualitative indicator of primary paleoproductivity, are used to rank the Late Jurassic terrestrial environments represented by the Morrison Formation in western North America, the informally named Lourinhã formation in Western Europe, and the Stanleyville Group in Central Africa. Because modern terrestrial environments show a positive correlation between primary productivity and faunal richness, a similar relationship is expected in ancient ecosystems. When the relative paleoproductivity levels inferred for each study area are compared with estimates of dinosaur generic richness, a positive correlation emerges. Both the Morrison and Lourinhã formations have high inferred productivity levels and high estimated faunal richness. In contrast, the Stanleyville Group appears to have had low primary productivity and low faunal richness. Paleoclimatic data available for each study area indicate that both productivity and faunal richness are positively linked to water availability, as observed in modern terrestrial ecosystems.

scholarly journals A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere

2009 ◽  
Vol 6 (5) ◽  
pp. 9891-9944 ◽  
Author(s):  
Y. P. Wang ◽  
R. M. Law ◽  
B. Pak
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Global Model ◽  
Terrestrial Biosphere ◽  
P Limitation ◽  
P Mineralization

Abstract. Carbon storage by many terrestrial ecosystems can be limited by nutrients, predominantly nitrogen (N) and phosphorous (P), in additional to other environmental constraints, water, light and temperature. However the spatial distribution and the extent of both N and P limitation at global scale have not been quantified. Here we have developed a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere. Model estimates of steady state C and N pool sizes and major fluxes between plant, litter and soil pools, under present climate conditions, agree well with various independent estimates. The total amount of C in the terrestrial biosphere is 2526 Gt C, and the C fractions in plant, litter and soil organic matter are 21, 6 and 73%. The total amount of N is 124 Gt N, with about 94% stored in the soil, 5% in the plant live biomass, and 1% in litter. We found that the estimates of total soil P and its partitioning into different pools in soil are quite sensitive to biochemical P mineralization that has not been included in any other global models previously. The total amount of P is 26 Gt P in the terrestrial biosphere, 17% of which is stored in the soil organic matter if biochemical P mineralization is modelled, or 40 Gt P, with 60% in soil organic matter, otherwise. This model was used to derive the global distribution of N or P limitation on the productivity of terrestrial ecosystems. Our model predicts that the net primary productivity of most tropical evergreen broadleaf forests and tropical savannahs is reduced by about 20% on average by P limitation, and most of the remaining biomes are N limited; N limitation is strongest in high latitude deciduous needle leaf forests, and reduces its net primary productivity by up to 40% under present conditions.

scholarly journals Drought-Induced Reduction in Net Primary Productivity across Mainland China from 1982 to 2015

2018 ◽  
Vol 10 (9) ◽  
pp. 1433 ◽  
Author(s):  
Chengguang Lai ◽  
Jun Li ◽  
Zhaoli Wang ◽  
Xiaoqing Wu ◽  
Zhaoyang Zeng ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Mainland China ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Tibet Plateau ◽  
Positive Correlation ◽  
Casa Model ◽  
Increasing Trend ◽  
Qinghai Tibet Plateau

Terrestrial net primary productivity (NPP) plays an essential role in the global carbon cycle as well as for climate change. However, in the past three decades, terrestrial ecosystems across mainland China suffered from frequent drought and, to date, the adverse impacts on NPP remain uncertain. This study explored the spatiotemporal features of NPP and discussed the influences of drought on NPP across mainland China from 1982 to 2015 using the Carnegie Ames Stanford Application (CASA) model and the standardized precipitation evapotranspiration index (SPEI). The obtained results indicate that: (1) The total annual NPP across mainland China showed an non-significantly increasing trend from 1982 to 2015, with annual increase of 0.025 Pg C; the spring NPP exhibited a significant increasing trend (0.031 Pg C year−1, p < 0.05) while the summer NPP showed a higher decreasing trend (0.019 Pg C year−1). (2) Most areas of mainland China were spatially dominated by a positive correlation between annual NPP and SPEI and a significant positive correlation was mainly observed for Northern China; specific to the nine sub-regions, annual NPP and SPEI shared similar temporal patterns with a significant positive relation in Northeastern China, Huang-Huai-Hai, Inner Mongolia, and the Gan-Xin Region. (3) During the five typical drought events, more than 23% areas of mainland China experienced drought ravage; the drought events generally caused about 30% of the NPP reduction in most of the sub-regions while the NPP in the Qinghai-Tibet Plateau Region generally decreased by about 10%.

scholarly journals A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere

2010 ◽  
Vol 7 (7) ◽  
pp. 2261-2282 ◽  
Author(s):  
Y. P. Wang ◽  
R. M. Law ◽  
B. Pak
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Soil Organic Matter ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Terrestrial Biosphere ◽  
P Limitation ◽  
P Mineralization

Abstract. Carbon storage by many terrestrial ecosystems can be limited by nutrients, predominantly nitrogen (N) and phosphorus (P), in addition to other environmental constraints, water, light and temperature. However the spatial distribution and the extent of both N and P limitation at the global scale have not been quantified. Here we have developed a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere. Model estimates of steady state C and N pool sizes and major fluxes between plant, litter and soil pools, under present climate conditions, agree well with various independent estimates. The total amount of C in the terrestrial biosphere is 2767 Gt C, and the C fractions in plant, litter and soil organic matter are 19%, 4% and 77%. The total amount of N is 135 Gt N, with about 94% stored in the soil, 5% in the plant live biomass, and 1% in litter. We found that the estimates of total soil P and its partitioning into different pools in soil are quite sensitive to biochemical P mineralization. The total amount of P (plant biomass, litter and soil) excluding occluded P in soil is 17 Gt P in the terrestrial biosphere, 33% of which is stored in the soil organic matter if biochemical P mineralization is modelled, or 31 Gt P with 67% in soil organic matter otherwise. This model was used to derive the global distribution and uncertainty of N or P limitation on the productivity of terrestrial ecosystems at steady state under present conditions. Our model estimates that the net primary productivity of most tropical evergreen broadleaf forests and tropical savannahs is reduced by about 20% on average by P limitation, and most of the remaining biomes are N limited; N limitation is strongest in high latitude deciduous needle leaf forests, and reduces its net primary productivity by up to 40% under present conditions.

scholarly journals Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO<sub>2</sub> tolerance in phytoplankton productivity

2018 ◽  
Vol 15 (1) ◽  
pp. 209-231 ◽  
Author(s):  
Stacy Deppeler ◽  
Katherina Petrou ◽  
Kai G. Schulz ◽  
Karen Westwood ◽  
Imojen Pearce ◽  
...  
Keyword(s):  
Organic Matter ◽  
Ocean Acidification ◽  
Primary Productivity ◽  
Phytoplankton Community ◽  
Bacterial Abundance ◽  
Critical Threshold ◽  
Bacterial Productivity ◽  
High Co2 ◽  
Chl A ◽  
Antarctic Marine

Abstract. High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343 µatm) to 1641 µatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a) and particulate organic matter (POM) in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140 µatm. CO2 levels  ≥ 1140 µatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C), causing significant reductions in gross primary production (GPP14C), Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C : N ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs) and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments  ≥ 953 µatm (days 3–5), yet gross bacterial production (GBP14C) remained unchanged and cell-specific bacterial productivity (csBP14C) was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON) combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative effects on the Antarctic food web and the biological pump, resulting in negative feedbacks on anthropogenic CO2 uptake. Increases in bacterial abundance under high CO2 conditions may also increase the efficiency of the microbial loop, resulting in increased organic matter remineralisation and further declines in carbon sequestration.

scholarly journals European survey shows poor association between soil organic matter and crop yields

2020 ◽  
Vol 118 (3) ◽  
pp. 325-334
Author(s):  
Wytse J. Vonk ◽  
Martin K. van Ittersum ◽  
Pytrik Reidsma ◽  
Laura Zavattaro ◽  
Luca Bechini ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Sugar Beet ◽  
Significant Positive Correlation ◽  
Agricultural Land ◽  
Crop Yields ◽  
Carbon Sink ◽  
Significant Negative Correlation ◽  
Positive Correlation ◽  
Farm Survey

AbstractA number of policies proposed to increase soil organic matter (SOM) content in agricultural land as a carbon sink and to enhance soil fertility. Relations between SOM content and crop yields however remain uncertain. In a recent farm survey across six European countries, farmers reported both their crop yields and their SOM content. For four widely grown crops (wheat, grain maize, sugar beet and potato), correlations were explored between reported crop yields and SOM content (N = 1264). To explain observed variability, climate, soil texture, slope, tillage intensity, fertilisation and irrigation were added as co-variables in a linear regression model. No consistent correlations were observed for any of the crop types. For wheat, a significant positive correlation (p < 0.05) was observed between SOM and crop yields in the Continental climate, with yields being on average 263 ± 4 (95% CI) kg ha−1 higher on soils with one percentage point more SOM. In the Atlantic climate, a significant negative correlation was observed for wheat, with yields being on average 75 ± 2 (95%CI) kg ha−1 lower on soils with one percentage point more SOM (p < 0.05). For sugar beet, a significant positive correlation (p < 0.05) between SOM and crop yields was suggested for all climate zones, but this depended on a number of relatively low yield observations. For potatoes and maize, no significant correlations were observed between SOM content and crop yields. These findings indicate the need for a diversified strategy across soil types, crops and climates when seeking farmers’ support to increase SOM.

scholarly journals Fate of unproductive and unattractive habitats: recent changes in Iberian steppes and their effects on endangered avifauna

2006 ◽  
Vol 33 (3) ◽  
pp. 223-232 ◽  
Author(s):  
PAOLA LAIOLO ◽  
JOSÉ L. TELLA
Keyword(s):  
Primary Productivity ◽  
Western Europe ◽  
Agricultural Development ◽  
Public Awareness ◽  
Species Dispersal ◽  
Ecological Value ◽  
Shrub Steppe ◽  
Steppe Birds ◽  
Dupont’S Lark ◽  
The Impact

Steppe ecosystems worldwide are affected by agricultural development and generally unprotected. Spanish shrub-steppes contain endangered avifauna, and this paper analyses their state of habitat conservation, the changes that have occurred in the last decade, primary productivity and its relationship with land exploitation and the richness of threatened birds, and avifauna responses to habitat loss. Fifty steppe remnants distributed throughout Spain and inhabited by Dupont's lark Chersophilus duponti, an endangered passerine representative of shrub steppe-like habitat, were studied. The study fragments were generally affected by agriculture exploitation, and steppe cover had significantly decreased in several isolated patches during the period 1991–1999. Steppe habitat recovered slightly in areas with low plant productivity indices, and decreased in extent in the most productive areas, in line with EU (European Union) agricultural policy recommendations to abandon marginal land of low productivity. The low overall primary productivity of Iberian steppes opened the way to industrial activities (mining, waste collection and wind-farming), which in the study areas occurred more frequently in steppe than in other habitat types that are more attractive to the public (woodland) or more productive (farmland). The emerging wind industry little affected the study plots, but the presence of anemometers suggests that the impact is likely to increase in the near future, especially in the largest steppelands. Dupont's lark was sensitive to the fragmentation of its habitat; crowding occurred in isolated and small fragments, possibly as a consequence of habitat constraints and species dispersal dynamics. Fragments inhabited by Dupont's lark also hosted other steppe birds with a high conservation value; the community of endangered birds, mostly adapted to arid conditions, was richest in the less productive sites. Only four shrub-steppe fragments are given some kind of protection throughout Spain, testifying to the limited public awareness about the value of this habitat. Urgent action is required to restore this habitat through abandonment of less productive farmland, and to create a network of protected and connected steppelands, in order to assure the long-term viability of steppe specialists and the preservation of a habitat that is unique in Western Europe. This should be coupled to an effort to increase social consciousness of the ecological value of steppes and arid landscapes in general.

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