nutrient input
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2022 ◽  
Vol 464 ◽  
pp. 109837
Author(s):  
Chen Zhang ◽  
Zixuan Zhu ◽  
Maria Špoljar ◽  
Natalia Kuczyńska-Kippen ◽  
Tvrtko Dražina ◽  
...  

Author(s):  
Gian Carlos Poleto ◽  
Dione Richer Momolli ◽  
Mauro Valdir Schumacher ◽  
Aline Aparecida Ludvichak ◽  
Kristiana Fiorentin dos Santos ◽  
...  

Given that atmospheric deposition is the first source of nutrient input into forest ecosystems, and that the precipitation partition serves as a nutritional source mainly when there is an interaction with the forest canopy, the objective of the present study was to quantify the nutrients input into rainfall, throughfall and stemflow in Eucalyptus urophylla stands with partial exclusion (E) and without exclusion (WE) of throughfall. The experiment was conducted in the northeast of the state of Paraná-Brazil, in the municipality of Telêmaco Borba. The partial precipitation exclusion system (E) is formed by a system of gutters that conduct 30% of throughfall out of the experiment. The nutrient input in rainfall was 55.7 kg ha-1 yr-1, while the sum of throughfall and stemflow was 64.1 kg ha-1 yr-1 in treatment (WE) and 39.8 kg ha-1 yr-1 in treatment (E). Interaction with the canopy of the trees enriched the rainfall with nutrients, mainly the elements potassium and chlorine, due to leaching of the vegetal tissues. The reduction of the water treatment system in partial exclusion of precipitation (E) reduced representative nutrient input. Although stemflow represents on average only 2.6% of the water volume, it is responsible for 6.7% of the amount of nutrients in relation to precipitation. Therefore, stemflow cannot be neglected in the balance of nutrient cycling. With a rotation of 7 years, the application of significant amounts of fertilizers can be avoided, considering the inputs of 449 and 277 kg ha-1year-1. Keywords: nutrient cycling, stemflow, throughfall.


2021 ◽  
Vol 9 (11) ◽  
pp. 1296
Author(s):  
Cheng-Shing Chiang ◽  
Ho-Shing Yu

There are four shelf-incising submarine canyons off SW Taiwan. They are distributed along the active continental margin, which is periodically flushed by gravity flows. Shelf-incising canyons, such as Kaoping Canyon, may not only be affected by oceanographic conditions but also by extreme climate change due to the direct input of river sediment. In the canyons along the SW margin of Taiwan, strong sedimentary flows are reflected in highly abundant nutrient input and physical disturbances. The Kaoping Canyon possesses habitats that promote biodiversity but that are sensitive to environmental change. The aims of this study are to review the canyons along the SW margin of Taiwan and to present their geomorphological features and associated ecosystems.


2021 ◽  
Vol 869 (1) ◽  
pp. 012056
Author(s):  
M Ramadhaniaty ◽  
C Octavina ◽  
FA Putri ◽  
S Karina ◽  
Ichsan

Abstract Crassostrea gigas is a Pacific oyster that has the largest size among the other oysters. This oyster is most often found because of its ability to adapt to a variety of environments. Krueng Cut is an estuary area that gets a lot of nutrient input from sea water because it is directly adjacent to the ocean. This condition makes this area has a high abundance of oysters with high fishing and antropogenic activities as well. The purpose of this study was to determine the density and distribution of the oyster population from 3 representative stations along the estuary area of Krueng Cut. The method used in this study is random sampling using a quadratic transect. The results show that the highest density is indicated by station 3 with 55.67 ind/m2 and the lowest density is indicated by station 1 is 40.33 ind/m2. These results indicate that the activities of residents, the entry of contaminants from antropogenic affect the density of oysters. The distribution of oysters from the three stations showed similarities, namely they tended to grouping. The aquatic environment at the three research stations still supports the growth of oysters. This study confirms that there has been a decline in the population, which is characterized by a decrease in the number of catches and a smaller size of oysters.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fabricio Caxito ◽  
Cristiano Lana ◽  
Robert Frei ◽  
Gabriel J. Uhlein ◽  
Alcides N. Sial ◽  
...  

AbstractWe combine U–Pb in-situ carbonate dating, elemental and isotope constraints to calibrate the synergy of integrated mountain-basin evolution in western Gondwana. We show that deposition of the Bambuí Group coincides with closure of the Goiás-Pharusian (630–600 Ma) and Adamastor (585–530 Ma) oceans. Metazoans thrived for a brief moment of balanced redox and nutrient conditions. This was followed, however, by closure of the Clymene ocean (540–500 Ma), eventually landlocking the basin. This hindered seawater renewal and led to uncontrolled nutrient input, shallowing of the redoxcline and anoxic incursions, fueling positive productivity feedbacks and preventing the development of typical Ediacaran–Cambrian ecosystems. Thus, mountains provide the conditions, such as oxygen and nutrients, but may also preclude life development if basins become too restricted, characterizing a Goldilocks or optimal level effect. During the late Neoproterozoic-Cambrian fan-like transition from Rodinia to Gondwana, the newborn marginal basins of Laurentia, Baltica and Siberia remained open to the global sea, while intracontinental basins of Gondwana became progressively landlocked. The extent to which basin restriction might have affected the global carbon cycle and climate, e.g. through the input of gases such as methane that could eventually have collaborated to an early Cambrian greenhouse world, needs to be further considered.


FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 803
Author(s):  
Maria Clécia Gomes Sales ◽  
Milton César Costa Campos ◽  
Elilson Gomes de Brito Filho ◽  
Luís Antônio Coutrim Dos Santos ◽  
José Maurício Da Cunha ◽  
...  

The soils of the Amazon region, despite being under one of the densest forests in the world, are mostly characterized by low nutrient availability, with litter being the main nutrient input route. The present work aimed to evaluate the litter decomposition in forest, Cerrado and Cerradão environments in the Amazon. The litter decomposition rate was estimated by mass loss analysis using litter bags. The collections were performed at intervals of 30, 60, 90, 120, 150, 180, 210, 240, 270 and 300 days, with four replications. Once collected, the material contained in each litter bag was placed to dry to obtain the dry mass. And so, the remaining mass percentage, the decomposition rates (k) and the half-life time (t1/2) are estimated. During the studied period, the Cerrado environment presented the lowest constant k (0.0017 g g-1 day-1) and consequently longer half-life (407 days). The monthly deposition in Cerrado input ranged from Mgha-1mother1 (June to September). Among the evaluated environments, the forest presented the highest decomposition speed and Cerrado presented the lowest one. It was evidenced that the decomposition process for all studied environments occurred with greater intensity in the rainy season.


2021 ◽  
Vol 43 (3) ◽  
pp. 336-346
Author(s):  
Tatyana GERASIMOVA ◽  
◽  
Anatoly SADCHIKOV ◽  

Based on a study of the dimensional structure of phytoand zooplankton, it is demonstrated that fi trophic press leads to a decrease in the population and size of zooplankton. Th isolation of fi zooplankton from planktoneating fi favors the development of largesize fi in particular, Daphnia magna and Daphnia longispina, which can consume cyanobacteria. In cases of high abundance, zooplankton breaks up large colonies and improves its food base. Planktoneating fi and hatchlings eat fi zooplankton, thereby indirectly contributing to the development of cyanobacteria. In cases of higher nutrient input in the absence of planktoneating fi fi zooplankton can regulate the development of phytoplankton, contributing to higher water transparency. Th main consumers of colonial cyanobacteria are largesize fi D. magna, D. longispina, etc.


2021 ◽  
Vol 20 (1) ◽  
pp. 21-33
Author(s):  
Nyamisi Peter ◽  
Masumbuko Semba ◽  
Charles Lugomela ◽  
Margareth Kyewalyanga

A study on the vertical pattern of chlorophyll-a (Chl-a) fluorescence was undertaken in the Mafia Channel offKimbiji, Tanzania. Data was collected during the Southeast Monsoon (SEM) and Northeast Monsoon (NEM) seasons. There was higher Chl-a concentration of 0.1 to 1.1 mgm-3 in the surface layer off Kimbiji to about 50 m depth due to the presence of mixed layer depth (MLD) which allowed water mixing in the layer. A deep Chl-a maximum was recorded at around 40 m depth during the NEM and between 40 and 70 m in the SEM. Surface water between longitude 39.9°E and 40.2°E had low Chl-a from the surface to about 50 m depth due to poor nutrient input. The NEM had an insignificantly higher Chl-a value than the SEM (p > 0.05) which differed from other studies in which Chl-a was higher during the SEM than the NEM, than, the Chl-a concentration was higher at the surface during the SEM than during the NEM. Satellite data showed higher Chl-a in the SEM than NEM, localized along the Mafia Channel. During the SEM season the wind pushes higher Chl-a water from the Mafia Channel towards the north and leads to a higher concentration at Kimbiji.


2021 ◽  
Vol 11 (1) ◽  
pp. 25-40
Author(s):  
Tereza Cahová ◽  
Barbora Chattová

The Antarctic diatom flora has been at the centre of interest of many studies in past decades. The present paper brings new information on the species richness, biogeography and community composition of diatoms on the Ardley Island, South Shetland Islands. One fresh-water and ten soil samples had been collected from the Antarctic Special protected area (ASPA) in the spring of 2019. The following analysis revealed eighty-six diatom taxa in well-developed communities, dominated by Luticola muticopsis, L. truncata, Pinnularia australoschoenfelderi, P. austroshetlandica and P. borealis. According to the current biogeographical knowledge, the majority of species have restricted distribution among the Antarctic Realm; 46.5% of them are reported from various islands of the Maritime Antarctic Region. Based on the dominance of species as Luticola muticopsis and L. truncata and their ecological preferences, we concluded that the species composition of the diatom communities is driven by high nutrient input from breeding seabirds and the moisture availability during the austral summer.


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