scholarly journals Eighty years of food-web response to interannual variation in discharge recorded in river diatom frustules from an ocean sediment core

2017 ◽  
Vol 114 (38) ◽  
pp. 10155-10159 ◽  
Author(s):  
John B. Sculley ◽  
Rex L. Lowe ◽  
Charles A. Nittrouer ◽  
Tina M. Drexler ◽  
Mary E. Power
Keyword(s):  
Food Web ◽  
Sediment Core ◽  
Nutrient Loading ◽  
Field Research ◽  
Growth Conditions ◽  
Early Summer ◽  
Depositional Environments ◽  
Annual Rainfall ◽  
Algal Production ◽  
Positive Effects

Little is known about the importance of food-web processes as controls of river primary production due to the paucity of both long-term studies and of depositional environments which would allow retrospective fossil analysis. To investigate how freshwater algal production in the Eel River, northern California, varied over eight decades, we quantified siliceous shells (frustules) of freshwater diatoms from a well-dated undisturbed sediment core in a nearshore marine environment. Abundances of freshwater diatom frustules exported to Eel Canyon sediment from 1988 to 2001 were positively correlated with annual biomass ofCladophorasurveyed over these years in upper portions of the Eel basin. Over 28 years of contemporary field research, peak algal biomass was generally higher in summers following bankfull, bed-scouring winter floods. Field surveys and experiments suggested that bed-mobilizing floods scour away overwintering grazers, releasing algae from spring and early summer grazing. During wet years, growth conditions for algae could also be enhanced by increased nutrient loading from the watershed, or by sustained summer base flows. Total annual rainfall and frustule densities in laminae over a longer 83-year record were weakly and negatively correlated, however, suggesting that positive effects of floods on annual algal production were primarily mediated by “top-down” (consumer release) rather than “bottom-up” (growth promoting) controls.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 1. Rationale, systems design and management

2014 ◽  
Vol 54 (3) ◽  
pp. 221 ◽  
Author(s):  
D. F. Chapman ◽  
J. Hill ◽  
J. Tharmaraj ◽  
D. Beca ◽  
S. N. Kenny ◽  
...  
Keyword(s):  
Milk Production ◽  
Perennial Ryegrass ◽  
Systems Design ◽  
Farming Systems ◽  
Early Summer ◽  
Annual Rainfall ◽  
Forage Production ◽  
Winter Cereal ◽  
Dairy Systems ◽  
Milk Solids

The profitability of dairy businesses in southern Australia is closely related to the amount of feed consumed from perennial ryegrass-dominant pasture. Historically, the dairy industry has relied on improvements in pasture productivity and utilisation to support profitable increases in stocking rate and milk production per hectare. However, doubts surround the extent to which the industry can continue to rely on perennial ryegrass technology to provide the necessary productivity improvements required into the future. This paper describes the design and management of a dairy systems experiment at Terang in south-west Victoria (780-mm average annual rainfall) conducted over four lactations (June 2005–March 2009) to compare the production and profitability of two forage base options for non-irrigated dairy farms. These options were represented by two self-contained farmlets each milking 36 mixed-age, autumn-calving Holstein-Friesian cows at peak: (1) well managed perennial ryegrass pasture (‘Ryegrass Max’, or ‘RM’); and (2) perennial ryegrass plus complementary forages (‘CF’) including 15% of farmlet area under double cropping with annual species (winter cereal grown for silage followed by summer brassica for grazing on the same land) and an average of 25% of farmlet area in perennial pasture based on tall fescue for improved late spring–early summer feed supply. The design of these systems was informed by farming systems models (DairyMod, UDDER and Redsky), which were used to estimate the effects of introducing different forage options on farm profitability. The design of the CF system was selected based on modelled profitability increases assuming that all forage components could be managed to optimise forage production and be effectively integrated to optimise milk production per cow. Using the historical ‘average’ pasture growth curve for the Terang district and a mean milk price of $3.71 per kg milk solids, the models estimated that the return on assets of the RM and CF systems would be 9.4 and 15.0%, respectively. The objectives of the experiment described here were to test whether or not such differences in profitability could be achieved in practice, and to determine the risks associated with including complementary forages on a substantial proportion of the effective farm area. Key results of the experiment are presented in subsequent papers.

scholarly journals NEW DATA ON THE EXTENT OF THE LAST PLEISTOCENE GLACIATION IN THE GORNAYA SHORIA

2017 ◽  
Vol 2017 (3) ◽  
pp. 24-26
Author(s):  
Марина Адаменко ◽  
Marina Adamenko ◽  
Ярослав Гутак ◽  
Yaroslav Gutak ◽  
Богдан Воробьев ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Field Research ◽  
Early Summer ◽  
Mountain Region ◽  
Pleistocene Glaciation ◽  
Mountain Valley ◽  
North East ◽  
Last Glaciation ◽  
Extreme North

The article presents and summarizes the results of a field research on glacial relief of the Gornaya Shoria mountain region, within the Patyn mountain massif. The Patyn-2017 expedition was organized by the Russian Geographic Society. This region has been very poorly studied in the paleogeographical aspect. The available material can give only an approximate assessment of last glaciation in the Gornaya Shoria mountain region. The massif of Mount Patyn (1630 m) is located in the extreme north-east of the Mountain Shoria on the watershed of the Tashtyk and the Mrassu rivers. At present, the massif is completely devoid of modern glaciation. Early summer snowfields appear on the leeward slopes of the eastern, southern and northern macroslopes. The moraine deposits and the configuration of the relief forms have proved mountain-valley glaciation in the Late Pleistocene. The article also touches upon the issue of the origin of the so-called «megaliths» of the massif of Pustag mountain.

scholarly journals Nitrogen fixation estimates for the Baltic Sea indicate high rates for the previously overlooked Bothnian Sea

AMBIO ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 203-214 ◽  
Author(s):  
Malin Olofsson ◽  
Isabell Klawonn ◽  
Bengt Karlson
Keyword(s):  
Nitrogen Fixation ◽  
Baltic Sea ◽  
Nutrient Loading ◽  
External Input ◽  
Nitrogen Loading ◽  
External Loading ◽  
The Baltic Sea ◽  
Positive Effects ◽  
The Baltic ◽  
Bothnian Sea

AbstractDense blooms of diazotrophic filamentous cyanobacteria are formed every summer in the Baltic Sea. We estimated their contribution to nitrogen fixation by combining two decades of cyanobacterial biovolume monitoring data with recently measured genera-specific nitrogen fixation rates. In the Bothnian Sea, estimated nitrogen fixation rates were 80 kt N year−1, which has doubled during recent decades and now exceeds external loading from rivers and atmospheric deposition of 69 kt year−1. The estimated contribution to the Baltic Proper was 399 kt N year−1, which agrees well with previous estimates using other approaches and is greater than the external input of 374 kt N year−1. Our approach can potentially be applied to continuously estimate nitrogen loads via nitrogen fixation. Those estimates are crucial for ecosystem adaptive management since internal nitrogen loading may counteract the positive effects of decreased external nutrient loading.

Post-fire ephemerals and spinifex-fuelled fires: a decision model for bilby habitat management in the Tanami Desert, Australia

2007 ◽  
Vol 16 (6) ◽  
pp. 741 ◽  
Author(s):  
Richard Southgate ◽  
Susan Carthew
Keyword(s):  
Habitat Suitability ◽  
Decision Model ◽  
Habitat Management ◽  
Fire History ◽  
Spatial Databases ◽  
Ground Cover ◽  
Weather Conditions ◽  
Early Summer ◽  
Annual Rainfall ◽  
Factors Affecting

Seed from post-fire ephemeral plants like Yakirra australiense can form an important component of the diet of the bilby, a threatened arid-dwelling bandicoot. An investigation was conducted to determine the factors affecting the production of Yakirra and fire reoccurrence in the Tanami Desert. A simple decision model was produced to assist managers decide where and when to burn and what to expect regarding Yakirra australiense growth following fire and rainfall. The information used in the model may be derived from existing spatial databases that document rainfall and fire history and could be used to map broad-scale temporal change in total vegetation cover and components of habitat suitability for the bilby. The season and magnitude of rainfall and time-since-fire were the most important variables in the production of Yakirra seed. Rainfall >300 mm within a 2-month period of intense-complete burns could result in >5% Yakirra cover, and >100 mm was required for >1% cover. Negligible Yakirra cover occurred in adjacent long-unburnt plots. Total ground cover and spinifex cover varied substantially in relation to mean annual rainfall, but not in relation to substrate type. Long-unburnt spinifex cover was mostly too sparse to carry a fire in the southern part of the Tanami and the growth of non-spinifex vegetation would be necessary to boost fuel loads sufficiently to carry a fire. Generally, more than 41% cover was required to carry a fire but this was also dependent on weather conditions. Managers should aim to burn in late spring or early summer to improve Yakirra production. Fire management to enhance habitat suitability for the bilby would be of most benefit in the northern part of the Tanami Desert where growth rate of vegetation is greater and there is little existing fire age heterogeneity.

WINTER WHEAT CROP FORMATION, DEPENDING ON THE FERTILIZER SYSTEM WHILE MINIMIZING BASIC TILLAGE

10.12737/3823 ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. 117-121
Author(s):  
Шаронова ◽  
Natalya Sharonova ◽  
Яппаров ◽  
Akhtam Yapparov ◽  
Ильясов ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Positive Impact ◽  
Wheat Yield ◽  
Field Research ◽  
Mineral Fertilizer ◽  
Wheat Crop ◽  
Positive Effects ◽  
Leached Chernozem ◽  
Fertilizer System

The article presents data of field research of fertilizers systems and tillage on heavy leached chernozem at planting winter wheat in the Republic of Tatarstan. The paper shows the positive effects of organomineral fertilizer system on crop growth and quality of winter wheat, compared with mineral fertilizer system. The improvement of water and soil nutrient status was revealed. The layered and chisel tillage systems were the most effective methods. The study showed, that the use of organomineral fertilizer system had a stronger positive impact on the yield and quality of winter wheat, compared with mineral fertilizer system. The most winter wheat yield was obtained by applying the organomineral fertilizer system at layered plowing - 4.49 tons per hectare (the increase relative to the control is 0.64 tons per hectare). The best indicators of water and food regime of leached chernozem also marked at using organomineral fertilizer system, especially in layered tillage .

scholarly journals The effects of service operation engineering and green marketing on consumer buying interest

2021 ◽  
Vol 9 (3) ◽  
pp. 603-608
Author(s):  
Yosi Pahala ◽  
Sri Widodo ◽  
Kadarwati Kadarwati ◽  
Munir Azhari ◽  
Muliyati Muliyati ◽  
...  
Keyword(s):  
Questionnaire Survey ◽  
Survey Methods ◽  
Field Research ◽  
Green Marketing ◽  
Survey Method ◽  
Dominant Effect ◽  
Positive Effects ◽  
Service Operation ◽  
Statistical Program ◽  
A Company

The purpose of this research is to determine the effects of service operation engineering and green marketing on consumer buying interest in a company in Jakarta. The analysis used in this research is a quantitative analysis technology using the statistical program analyzed by the SPSS 21 version of the program. In this study, the sample size is as many as 145 people. The data in this study are raw data, obtained through field research using questionnaire survey methods. The questionnaire survey method is a method of collecting data using a list of questions that must be filled out by the interviewee. The results of the survey indicate that service operation engineering and green marketing had some positive effects on consumers' buying interest. Service operation engineering has a dominant effect on consumer buying interest. For increasing consumer buying interest, service operation engineering is very important, since green marketing will implement service operation engineering support.

scholarly journals Ecosystem Entanglement and the Propagation of Nutrient-Driven Instability

2020 ◽  
Author(s):  
Kevin S. McCann ◽  
A.S MacDougall ◽  
G.F. Fussmann ◽  
C. Bieg ◽  
K. Cazelles ◽  
...  
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Nutrient Loading ◽  
Transport Theory ◽  
Nutrient Addition ◽  
Edible Plant ◽  
Nutrient Additions ◽  
Theoretical Synthesis ◽  
Human Modification ◽  
And Function

ABSTRACTAlmost 50 years ago, Michael Rosenzweig pointed out that nutrient addition can destabilize food webs, leading to loss of species and reduced ecosystem function through the paradox of enrichment. Around the same time, David Tilman demonstrated that increased nutrient loading would also be expected to cause competitive exclusion leading to deleterious changes in food web diversity. While both concepts have greatly illuminated general diversity-stability theory, we currently lack a coherent framework to predict how nutrients influence food web stability across a landscape. This is a vitally important gap in our understanding, given mounting evidence of serious ecological disruption arising from anthropogenic displacement of resources and organisms. Here, we combine contemporary theory on food webs and meta-ecosystems to show that nutrient additions are indeed expected to drive loss in stability and function in human-impacted regions. However, this loss in stability occurs not just from wild oscillations in population abundance, but more frequently from the complete loss of an equilibrium due to edible plant species being competitively excluded. In highly modified landscapes, spatial nutrient transport theory suggests that such instabilities can be amplified over vast distances from the sites of nutrient addition. Consistent with this theoretical synthesis, the empirical frequency of these distant propagating ecosystem imbalances appears to be growing. This synthesis of theory and empirical data suggests that human modification of the Earth’s ecological connectivity is “entangling” once distantly separated ecosystems, causing rapid, expansive, and costly nutrient-driven instabilities over vast areas of the planet. The corollary to this spatial nutrient theory, though -- akin to weak interaction theory from food web networks -- is that slow spatial nutrient pathways can be potent stabilizers by moderating flows across a landscape.

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