scholarly journals Rethinking the Role of Nitrogen and Phosphorus in the Eutrophication of Aquatic Ecosystems

EDIS ◽  
2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Ashley Smyth ◽  
H. Dail Laughinghouse ◽  
Karl Havens ◽  
Thomas Frazer

Nitrogen and phosphorus are two nutrients that are essential for the growth and survival of plants and animals but are often present in short supply. Both nitrogen and phosphorus are applied regularly through fertilizer to increase the yield of crops needed to feed human populations and for residential and commercial landscaping purposes. This publication contains information for stakeholders, students, scientists, and environmental agencies interested in understanding how nitrogen and phosphorus affect water resources. Major revision by Ashley Smyth, H. Dail Laughinghouse IV, Karl Havens, and Thomas Frazer; 5 pp.https://edis.ifas.ufl.edu/sg118

Author(s):  
I.D. Rutherfurd

The Southern Hemisphere island continent of Australia (7 million km2) is old, flat, stable, and dry, with a high proportion of endemic biota. The environment of Australia is fundamentally shaped by its age, its aridity and interannual climate variability, and the role of fire. These help to explain the continent’s characteristic ecology, animals, and evergreen vegetation. Fire has also been the main tool used by indigenous populations to substantially alter the landscape in their 50,000 years of occupation. In just 200 years, a relatively small population of European colonizers (by world standards) has even more effectively transformed the environment of Australia through mining, land use change, invasive plants and animals, exploitation of water resources, and water quality degradation. Very high endemism is matched by some of the world’s highest rates of extinctions of plants and animals. Although human populations are clustered in capital cities, and on the coast, particular pressure has come on three globally notable environments: the Great Barrier Reef, Northern Australia, and the Great Artesian Basin. Parallel with destruction has been preservation, and Australia has a long history of environmental protection. Nearly 12 percent of the continent is in protected areas, including Australia’s sixteen UNESCO World Heritage Areas. There are also some globally notable developments in environmental management, including the burgeoning role of indigenous groups in managing over 30 percent of the continent, and radical water management in response to overexploitation of water resources. In the early 21st century, climate change influences every aspect of Australia’s environment. Australia also has seven external territories (including 42 percent of Antarctica) that are also of great environmental importance but are not covered in this review.


1999 ◽  
Vol 40 (3) ◽  
pp. 187-194
Author(s):  
M. Nemcova ◽  
D. Cadelli ◽  
M. Radoux

Tests were carried out in a small-scale experimental plant. The system consisted of aquatic ecosystems without macrophytes (stage I) followed by semi-aquatic ecosystems planted with Typha latifolia L. (stage II). The outflow of stage II was evenly distributed into 10 units of terrestrial ecosystems (stage III), planted with ligneous species or without vegetation (control). The whole plant received a hydraulic load of 384 1/day of urban wastewaters. The net treatment area per person equivalent (PE) was 8 m2. The study focused on the evaluation of the role of terrestrial ecosystems mainly in tertiary treatment (nitrogen and phosphorus removal). Stages I and II with a surface area of 4 m2/PE assure a primary and secondary purification level that conforms with European standards. As for the tertiary treatment, removal efficiency remains inadequate. The primary and secondary efficiencies were considerably enhanced by installing terrestrial ecosystems after the two previous stages. The outflow water of all tested successions respects the European norms for suspended solids (35 mg/l), COD (125 mg/l) and BOD5 (25 mg/l). Concerning tertiary efficiency, the planted ecosystems systematically enhance nitrogen and phosphorus removal compared to the control sand. The succession with Salix has shown the best results. The outflow concentrations were 0.8 and 3.7 mg/l of total nitrogen and 1.8 and 1.3 mg/l of total phosphorus respectively (average values for periods 1995 and 1996). The control successions containing non-planted unit (sand) were significantly the least efficient for both nitrogen and phosphorus removal.


2010 ◽  
Vol 18 (1) ◽  
pp. 152-157 ◽  
Author(s):  
Zhi-Yong ZHANG ◽  
Jian-Chu ZHENG ◽  
Hai-Qin LIU ◽  
Zhi-Zhou CHANG ◽  
Liu-Gen CHEN ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Antonio J. Mendoza-Fernández ◽  
Araceli Peña-Fernández ◽  
Luis Molina ◽  
Pedro A. Aguilera

Campo de Dalías, located in southeastern Spain, is the greatest European exponent of greenhouse agriculture. The development of this type of agriculture has led to an exponential economic development of one of the poorest areas of Spain, in a short period of time. Simultaneously, it has brought about a serious alteration of natural resources. This article will study the temporal evolution of changes in land use, and the exploitation of groundwater. Likewise, this study will delve into the technological development in greenhouses (irrigation techniques, new water resources, greenhouse structures or improvement in cultivation techniques) seeking a sustainable intensification of agriculture under plastic. This sustainable intensification also implies the conservation of existing natural areas.


2002 ◽  
Vol 64 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Soroosh Sorooshian ◽  
Martha P. L. Whitaker ◽  
Terri S. Hogue

Blood ◽  
2003 ◽  
Vol 101 (5) ◽  
pp. 1962-1969 ◽  
Author(s):  
Luisa Granziero ◽  
Paola Circosta ◽  
Cristina Scielzo ◽  
Elisa Frisaldi ◽  
Stefania Stella ◽  
...  

Growth and survival of chronic B-cell tumors are favored by the malignant cell's capacity to respond to selected microenvironmental stimuli provided by nontumoral bystander cells. To investigate which mechanisms operate in these crosstalks and whether they are malignancy-related or reproduce the mechanisms used by normal B cells we have studied the expression and functional role of semaphorin CD100 (now called Sema4D) in chronic lymphocytic leukemia (CLL) cells and normal CD5+ B cells. We demonstrate here that (1) leukemic and normal CD5+ B lymphocytes uniformly express CD100; (2) the CD100 high-affinity receptor Plexin-B1 is expressed by bone marrow stromal cells, follicular dendritic cells, and activated T lymphocytes, and is thus available to CD100+ lymphocytes in different specific microenvironments; and (3) upon interaction between CD100 and Plexin-B1 both CLL and normal CD5+ B cells increase their proliferative activity and extend their life span. These findings establish that Plexin-B1 is an easily accessible receptor for CD100 within the immune system. The encounter of CD100+ leukemic cells with Plexin-B1 may promote the proliferation and survival of malignant cells. The crosstalk operated by the CD100/Plexin-B1 interaction is not malignancy related but reproduces a mechanism used by normal CD5+ B cells.


1976 ◽  
Vol 54 (4) ◽  
pp. 531-535 ◽  
Author(s):  
M. P. Komourdjian ◽  
R. L. Saunders ◽  
J. C. Fenwick

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.


2021 ◽  
Vol 22 (3) ◽  
pp. 1103
Author(s):  
Marco Cippitelli ◽  
Helena Stabile ◽  
Andrea Kosta ◽  
Sara Petillo ◽  
Angela Gismondi ◽  
...  

The Ikaros zing-finger family transcription factors (IKZF TFs) are important regulators of lymphocyte development and differentiation and are also highly expressed in B cell malignancies, including Multiple Myeloma (MM), where they are required for cancer cell growth and survival. Moreover, IKZF TFs negatively control the functional properties of many immune cells. Thus, the targeting of these proteins has relevant therapeutic implications in cancer. Indeed, accumulating evidence demonstrated that downregulation of Ikaros and Aiolos, two members of the IKZF family, in malignant plasma cells as well as in adaptative and innate lymphocytes, is key for the anti-myeloma activity of Immunomodulatory drugs (IMiDs). This review is focused on IKZF TF-related pathways in MM. In particular, we will address how the depletion of IKZF TFs exerts cytotoxic effects on MM cells, by reducing their survival and proliferation, and concomitantly potentiates the antitumor immune response, thus contributing to therapeutic efficacy of IMiDs, a cornerstone in the treatment of this neoplasia.


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