scholarly journals Association Between Estuary Characteristics and Activities of the Critically Endangered Indo-Pacific Humpback Dolphin (Sousa chinensis)

2021 ◽  
Vol 8 ◽  
Author(s):  
Chi-hung Lin ◽  
Hsing-Juh Lin ◽  
Jian-Ping Suen ◽  
Lien-Siang Chou
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
River Estuary ◽  
Late Summer ◽  
Critically Endangered ◽  
Physical Factors ◽  
Factors Affecting ◽  
Net Production ◽  
Sousa Chinensis ◽  
Autumn And Winter

The Indo-Pacific humpback dolphin (Sousa chinensis) has been reported to prefer estuary habitats. This study explored the environmental factors affecting a critically endangered population off the coast of Yunlin, Taiwan. We measured dolphin sighting rates and estuary characteristics affected by the watershed, including seven physical factors (watershed rainfall, watershed runoff, estuarine turbidity, pH, salinity, temperature, and dissolved oxygen) and two biological factors (estuarine net primary production and chlorophyll a concentration), at the Hsinhuwei River estuary in Taiwan. Dolphin activity was measured by sighting rate and behavioral indices for feeding and traveling between 2017 and 2018. We observed that when the maximum net production increased alongside rising temperatures in spring, both the dolphin sighting rate and foraging activity increased. This trend was maintained until heavy rainfall or increased river runoff occurred during late summer, which resulted in high turbidity in autumn and winter. Turbidity was significantly negatively correlated with dolphin activity (sighting rate and foraging). Furthermore, we found that dolphin traveling positively correlated with the chlorophyll a concentration and maximum net production factors, which could attract dolphins expecting more abundant prey fish in the estuary supported by the high primary production. This study provides empirical evidence on how estuary characteristics affected by the watershed can affect the sighting rate and behavioral activities of Indo-Pacific humpback dolphins.

scholarly journals On the accuracy of official Chinese crop production data: Evidence from biophysical indexes of net primary production

2020 ◽  
Vol 117 (41) ◽  
pp. 25434-25444 ◽  
Author(s):  
Gengyuan Liu ◽  
Xueqi Wang ◽  
Giovanni Baiocchi ◽  
Marco Casazza ◽  
Fanxin Meng ◽  
...  
Keyword(s):  
Primary Production ◽  
Data Quality ◽  
Crop Production ◽  
Net Primary Production ◽  
Production Data ◽  
Physical Factors ◽  
National Statistics ◽  
Rapid Economic Growth ◽  
Self Sufficiency ◽  
Economic Statistics

With rapid economic growth and urbanization, self-sufficiency in crop production has become central to China’s agriculture policy. Accurate crop production statistics are essential for research, monitoring, and planning. Although researchers agree that China’s statistical authority has considerably modernized over time, China’s economic statistics have still been viewed as unreliable and often overstated to meet growth targets at different administrative levels. Recent increases in crop production reported by national statistics have also come under increasing scrutiny. This paper investigates crop production data quality from a planetary boundary perspective—comparing net primary production (NPP) harvested obtained from national statistics with satellite-driven NPP estimates that are supported by detailed observation of land cover, combined with observations on physical factors that limit plant growth. This approach provides a powerful means to check the plausibility of China’s grain production statistics at different administrative levels that can generate insights about their discrepancies and can contribute to improved crop production measurements. We find some evidence of potential misreporting problems from the lower administration level where the risk of manipulation of statistics is higher. We also find problems from provincial-level major grain producers. These values can also affect the national totals. Although the numbers are affected by large uncertainties, we find that improving the spatial resolution of key agricultural parameters can greatly improve the reliability of the indicator that in turn can help improve data quality. More reliable production data will be vital for relevant research and provide better insights into food security problems, the carbon cycle, and sustainable development.

Variation in foliar nitrogen and aboveground net primary production in young postfire lodgepole pine

2009 ◽  
Vol 39 (5) ◽  
pp. 1024-1035 ◽  
Author(s):  
Monica G. Turner ◽  
Erica A.H. Smithwick ◽  
Daniel B. Tinker ◽  
William H. Romme
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Lodgepole Pine ◽  
Tree Density ◽  
Aboveground Net Primary Production ◽  
Foliar Nitrogen ◽  
Net Production ◽  
Foliar N ◽  
N Concentration ◽  
Foliar N Concentration

Understanding nutrient dynamics of young postfire forests may yield important insights about how stands develop following stand-replacing wildfires. We studied 15-year-old lodgepole pine stands that regenerated naturally following the 1988 Yellowstone fires to address two questions: (1) How do foliar nitrogen (N) concentration and total foliar N vary with lodgepole pine density and aboveground net primary production? (2) Is foliar N related to litter production and to rates of gross production, consumption, and net production of soil NH4+ and NO3–? Foliar N concentration of new lodgepole pine needles averaged 1.38%; only stands at very high density (>80 000 trees·ha–1) approached moderate N limitation. Foliar N concentration in composite (all-age) needles averaged 1.08%, varied among stands (0.87%–1.39%), and declined with increasing tree density. The foliar N pool averaged 48.3 kg N·ha–1, varied among stands (3.6–218.4 kg N·ha–1), and increased with aboveground net primary production. Total foliar N was not related to laboratory estimates of net production of NH4+ or NO3– in soils. Lodgepole pine foliage is a strong N sink, and N does not appear to be limiting at this early successional state. The initial spatial patterns of postfire tree density strongly influence landscape patterns of N storage.

Biomass distribution and above- and below-ground production in young and mature Abiesamabilis zone ecosystems of the Washington Cascades

1981 ◽  
Vol 11 (1) ◽  
pp. 155-167 ◽  
Author(s):  
Charles C. Grier ◽  
Kristiina A. Vogt ◽  
Michael R. Keyes ◽  
Robert L. Edmonds
Keyword(s):  
Primary Production ◽  
Fine Root ◽  
Net Primary Production ◽  
Root Production ◽  
Fine Root Production ◽  
Biomass Distribution ◽  
Net Production ◽  
Young Stand ◽  
Mature Stand ◽  
Below Ground

Biomass distribution and above- and below-ground net primary production were determined for 23- and 180-year-old Abiesamabilis (Dougl.) Forbes ecosystems growing at 1200-m elevation in the western Washington Cascade Range. Total organic matter accumulations were 427.0 t•ha−1 in the young stand, and 1247.1 t•ha−1 in the mature stand. Aboveground tree and detritus biomass were 49.0 t•ha−1 and 130.2 t•ha−1, respectively, in the young stand compared with 445.5 t•ha−1 and 389.4 t•ha−1 in the mature stand. Net primary production (NPP) was 18.3 t•ha−1 in the young stand and 16.8 t•ha−1 in the mature stand. Belowground dry matter production was 65% of total net production in the young stand and 73% of total net production in the mature stand. Conifer fine root production was 35.9% of NPP in the young and 66.4% of NPP in the mature stand. This apparent shift in fine root production as a proportion of NPP may be related to detritus accumulation.

Factors affecting the productivity of irrigated annual pastures. 1. Time of first irrigation in late summer-early autumn

1986 ◽  
Vol 26 (3) ◽  
pp. 297 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Nitrogen Content ◽  
Irrigation Treatment ◽  
Subterranean Clover ◽  
Late Summer ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Factors Affecting ◽  
Autumn And Winter ◽  
Clover Content

The influence of time of first irrigation (mid-February, early March, or late March) on the productivity of an annual pasture was studied for 3 years in northern Victoria. Beginning the irrigation of annual pastures in late summer instead of at the normal time of late March- April provided additional herbage in autumn and winter and did not adversely affect herbage production in late winter-early spring; up to 2.3 t/ha DM of additional herbage was obtained by mid June and 4.3 t/ha DM over the whole season. Earlier irrigation also increased the subterranean clover content of the pasture, resulting in herbage that was lower in digestibility and higher in nitrogen content than that in the other treatments. The benefit of early irrigation in increasing clover content may be offset by invasion by weeds. In this experiment, a potential weed problem in the earliest irrigation treatment appeared at the beginning of year 3.

scholarly journals PRODUCTIVIDAD PRIMARIA EN LAGUNA LARGA, CAYO COCO, CUBA

2011 ◽  
Vol 3 ◽  
pp. 31 ◽  
Author(s):  
Mayrene Guimarais Bermejo ◽  
Roberto González de Zayas
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Net Primary Production ◽  
Ruppia Maritima ◽  
Halodule Wrightii ◽  
Phytoplankton Productivity ◽  
North Central ◽  
Net Production ◽  
The North ◽  
Total Productivity

Se determinó la productividad primaria en Laguna Larga, ubicada en la costa norte y central de Cayo Coco. La producción primaria del fitoplancton y la biomasa del macrofitobentos fueron medidas durante el 2008-2009 en dos sectores de la laguna. La producción primaria neta acuática del sector este fue de 4.32 ± 3.59 g C m-2 día-1 y en el sector oeste fue de 0.71 ± 0.41 g C m-2 día-1. Ambos sectores, atendiendo a la relación producción/respiración anual, fueron autotróficos para el oxígeno e hipertróficos para el carbono. Entre las especies más productivas del macrofitobentos estuvieron: Cladophoropsis sp., Halodule wrightii, Cladophora sp. y Ruppia maritima. La alta producción neta acuática registrada en el sector este, con respecto al oeste, se debe a la contribución del macrofitobentos a la productividad total. El fitoplancton en el sector este exhibió baja productividad (0.12 ± 0.07 g C m-2 día-1) con respecto al oeste (0.71 ± 0.41 g C m-2 día-1), lo que puede deberse a la competencia del macrofitobentos por los nutrientes.ABSTRACT Phytoplankton primary productivity and macrophyte biomass were determined during 2008-2009 for Laguna Larga, located on the north-central coast of Cayo Coco, Cuba. Aquatic net primary production was measured in two different sectors of the lagoon resulting in 4.32 ± 3.59 g C m-2 d-1 and 0.71 ± 0.41 g C m-2 d-1 in the eastern and western part, respectively. In regard to the annual production to respiration ratio, both sections showed autotrophic and hypertrophic levels for the oxygen and carbon metabolisms. The most productive species were Cladophoropsis sp., Halodule wrightii, Cladophora sp. and Ruppia maritima. Aquatic net production recorded for the eastern lobe was higher than the western lobe because of the macrophytobenthos contribution to total productivity. On the contrary, phytoplankton productivity in the eastern part was lower (0.12 ± 0.07 g C m-2 d-1) than the western lobe (0.71 ± 0.41 g C m-2 d-1), probably due to the macrophyte competition for nutrients.

Growth and net production of Sphagnum at five fen sites, subarctic eastern Canada

1989 ◽  
Vol 67 (4) ◽  
pp. 1203-1207 ◽  
Author(s):  
T. R. Moore
Keyword(s):  
Primary Production ◽  
Air Temperature ◽  
Net Primary Production ◽  
Mean Annual Temperature ◽  
Eastern Canada ◽  
Net Production ◽  
Sphagnum Fuscum ◽  
Average Rainfall ◽  
Wire Method

Growth in length and net primary production (NPP) were measured by the cranked wire method at five sites near Schefferville, northern Quebec, representing lawns of Sphagnum angustifolium, Sphagnum warnstorfii, S. warnstorfii/S. angustifolium, and hummocks of Sphagnum fuscum and Sphagnum capillifolium. From June to September, growth and NPP ranged from 4 to 24 mm and 29 to 142 g m−2, respectively. In an average rainfall year (1984), growth at the three lawn sites was higher than in the hummocks. In a dry year (1985, with half the average rainfall), growth in two of the three lawn sites was lower than in the hummocks. Growth of Sphagnum was weakly correlated with macroclimatic variables, such as air temperature, precipitation, and sunshine. The literature for Sphagnum production from arctic to temperate regions showed that hummock NPP was less than that of adjacent lawn/hollow sites and that a significant (r2 = 0.307, P < 0.001) portion of the variation in NPP can be ascribed to mean annual temperature.

scholarly journals Monthly Changes in Atmospheric Carbon Dioxide at Mauna Loa: Possible Asymmetric Effects of Warming

2007 ◽  
Vol 11 (10) ◽  
pp. 1-16 ◽  
Author(s):  
Robert K. Kaufmann
Keyword(s):  
Primary Production ◽  
Atmospheric Carbon Dioxide ◽  
Net Primary Production ◽  
Late Summer ◽  
Mean Value ◽  
Early Spring ◽  
Heterotrophic Respiration ◽  
Mauna Loa ◽  
Asymmetric Effects ◽  
Enso Events

Abstract Changes in the intra-annual cycle of atmospheric CO2 at Mauna Loa, Hawaii, are investigated by comparing monthly observations to the mean value of each year’s waxing and waning phase of the cycle. Results identify a previously unnoticed change between 1965 and 2004 during October in which October concentrations declined relative to the cycle’s mean value. Results confirm a previously noted change in spring (April), but unlike previous analyses, this result indicates that between 1965 and 2004 April concentrations rose relative to the cycle’s mean value. The timing of these changes is not caused by commonly recognized patterns of atmospheric circulation, such as ENSO events. Instead, these changes may be generated by asymmetric effects of warming. Warming in early spring may increase heterotrophic respiration relative to net primary production while warming in late summer/early fall may enhance net primary production relative to heterotrophic respiration.

scholarly journals Influence of seasonal monsoons on net primary production and CO<sub>2</sub> in subtropical Hong Kong coastal waters

2010 ◽  
Vol 7 (4) ◽  
pp. 5621-5647
Author(s):  
X. C. Yuan ◽  
K. D. Yin ◽  
W.-J. Cai ◽  
A. Y. T. Ho ◽  
J. Xu ◽  
...  
Keyword(s):  
Hong Kong ◽  
Primary Production ◽  
Coastal Waters ◽  
Net Primary Production ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Wet Season ◽  
The Pearl River ◽  
Hong Kong Coastal Waters

Abstract. Data from seven cruises in three different environments including the Pearl River estuary, sewage discharge outfall and eastern coastal/shelf waters, were used to examine the seasonal variations in net primary production (NPP) and the biologically active gases O2 and CO2. In the winter dry season, when monsoon-induced downwelling was dominant, NPP was low (−60±50 mmol C m−2 d−1) in all three regions. The negative NPP corresponded to low O2 influxes (−100±50 mmol O2 m−2 d−1) and CO2 effluxes (24±10 mmol C m−2 d−1). In the summer wet season, when upwelling brought the bottom oceanic waters to the nearshore due to the southwest monsoonal wind, there was a 2 to 15-fold increase in integrated primary production (IPP) compared to winter. The increase in IPP was likely due to the favorable conditions such as stratification and the nutrient inputs from upwelled waters and the Pearl River estuary. NPP reached up to 240±100 mmol C m−2 d−1 in the wet season. However, accompanying the high positive NPP, we observed an influx of O2 (−100±60 mmol O2 m−2 d−1) and efflux of CO2 (25±15 mmol C m−2 d−1). The high positive NPP corresponding to a CO2 source and O2 sink could be explained by the influence of the southwest monsoon-induced upwelling, as the upwelling brought cold, low DO (160±30 μM) and high DIC (1960±100 μatm) water to the surface in the wet season. Hence, the subtropical Hong Kong coastal waters are generally a CO2 source due to the monsoonal influence in both the dry and wet seasons.

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