An In Situ Substratum Fertilization Technique: Diatom Colonization on Nutrient-Enriched, Sand Substrata

1984 ◽  
Vol 41 (8) ◽  
pp. 1247-1251 ◽  
Author(s):  
Catherine M. Pringle ◽  
James A. Bowers
Keyword(s):  
Current Flow ◽  
Nutrient Release ◽  
Multiple Comparisons ◽  
Nutrient Concentrations ◽  
Release Rates ◽  
Enrichment Method ◽  
Petri Dishes ◽  
Colonization Period ◽  
Northern Michigan

Using an in situ substratum enrichment method, we assessed the effects of nutrient release from sand substrata on the community structure of attached diatoms in a sand-bottomed, northern Michigan stream. Sand from the stream bottom was washed, sterilized, and then consolidated into small plastic petri dishes with agar solutions enriched with various concentrations of NaNO3 and KH2PO4. Laboratory estimates of nutrient release rates were performed over a 144-h period with uncolonized substrata having different agar and nutrient concentrations. Release rates decreased 10-fold in an exponential fashion with no significant differences between replicates. Agar concentrations had no significant effect on release rates, although the rates were proportional to nutrient concentrations in the substratum. Racks of substrata were installed parallel to the stream current flow and retrieved after a 6-wk colonization period. Using multiple comparisons of treatment means for both nutrients and algal taxa, we found no differences between control and NO3 enrichments; significant differences were found, however, between PO4 and NO3 + PO4 (N:P = 25:1) treatment means relative to each other and the control. Diatom biovolume was two times as great on PO4 treatments and four times greater on NO3 + PO4 treatments. Effects of PO4 and NO3 enrichment appear to be taxa specific, with PO4and NO3 + PO4 treatments favoring Navicula and Nitzschia spp. Control and NO3 treatments were dominated by Cocconeis placentula Ehr. and Achnanthes minutissima Kutz.

scholarly journals Bioturbation, ecosystem functioning and community structure

2002 ◽  
Vol 6 (6) ◽  
pp. 999-1005 ◽  
Author(s):  
C. L. Biles ◽  
D. M. Paterson ◽  
R. B. Ford ◽  
M. Solan ◽  
D. G. Raffaelli
Keyword(s):  
Community Structure ◽  
Water Column ◽  
Ecosystem Functioning ◽  
Nutrient Concentration ◽  
Nutrient Release ◽  
Nutrient Concentrations ◽  
Infaunal Community ◽  
Significant Difference ◽  
In Situ Experiments

Abstract. The effect of community structure on the functioning of the ecosystem is an important issue in ecology due to continuing global species loss. The influence of infaunal community structure on the functioning of marine systems is proposed here to act primarily through bioturbation of the sediment. Nutrient concentration in the water column, generated by release from the sediment, was used as a measure of ecosystem functioning. In situ and laboratory experiments showed a significant difference in nutrient concentrations with different species treatments. Bioturbation profiles showing the incorporation of tracer particles also differed between communities with different dominant species. The behavioural differences between infaunal species, generating different modes and rates of bioturbation, are therefore proposed to influence nutrient release. The presence and quantity of bioturbating infauna also influenced the amount of sediment suspended in the water column. The increase in surface area available for microbial activity may generate an increase in nutrient cycling. Abiotic influences on sediment structure, such as flow, may have a similar effect on nutrient concentration. Annular flumes used in both laboratory and in situ experiments to generate flow conditions produced a significant increase in ammonia (NH4-N) production in macrofaunal treatments. Flow may influence the behaviour of macrofaunal species, causing changes in NH4-N production through modifying bioturbation of the sediment. Keywords: bioturbation, community structure, ccosystem functioning, estuaries, flow, infauna

scholarly journals Decomposition and nutrient release from fresh and dried pine roots under two fertilizer regimes

2006 ◽  
Vol 36 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Kim H Ludovici ◽  
Lance W Kress
Keyword(s):  
Mass Loss ◽  
Loblolly Pine ◽  
Fine Roots ◽  
Mass Loss Rate ◽  
Nutrient Release ◽  
Nutrient Content ◽  
Root Decomposition ◽  
Nutrient Concentrations ◽  
Release Rates ◽  
Root Tissues

Root decomposition and nutrient release are typically estimated from dried root tissues; however, it is unlikely that roots dehydrate prior to decomposing. Soil fertility and root diameter may also affect the rate of decomposition. This study monitored mass loss and nutrient concentrations of dried and fresh roots of two size classes (<2 and 2–5 mm) over a 12-month period in fertilized and control plots in a 13-year-old loblolly pine (Pinus taeda L.) plantation. Nutrient content was calculated and used to assess the effects of fertilization, root size, and initial condition (hydration) on nutrient release rates. Roots that grew and decomposed in fertilized plots had higher concentrations and greater total release of N, P, K, and Mg than roots in control plots, but C concentrations and mass loss rate were not significantly different between roots in fertilized plots and those in control plots. Very fine roots (<2 mm) had higher concentrations of N, P, and Ca and faster release rates for C, N, and K than fine roots (2–5 mm), resulting in greater total release of C and N. Roots dried prior to decomposition decayed and released C, K, Ca, and Mg at a faster rate than fresh roots. Results indicate that using dried root tissues will overestimate fine root decomposition and nutrient cycling rates.

Development of a water temperature-ecological model to stimulate global warming effects on lake ecosystem

1996 ◽  
Vol 34 (7-8) ◽  
pp. 237-244 ◽  
Author(s):  
Masaaki Hosomi ◽  
Tetsu Saigusa ◽  
Kenichi Yabunaka ◽  
Takuya Okubo ◽  
Akihiko Murakami
Keyword(s):  
Global Warming ◽  
Water Temperature ◽  
Thermal Stratification ◽  
Ecological Model ◽  
Nutrient Release ◽  
Eddy Diffusion ◽  
Nutrient Concentrations ◽  
Lake Ecosystem ◽  
Phytoplankton Species ◽  
Freezing And Thawing

This paper describes a newly developed combined water temperature-ecological (WT-ECO) model which is employed to simulate the effects of global warming on lake and reservoir ecosystems. The WT model includes (i) variations in the eddy diffusion coefficient based on the degree of thermal stratification and the velocity of wind, and (ii) a sub-model for simulating the freezing and thawing processes of surface water, water temperatures, and the mixing rates between two adjacent layers of water. The ECO model then uses these results to calculate the resultant effect on a lake's ecological dynamics, e.g., composition of phytoplankton species, their respective concentrations, and nutrient concentrations. When the model was benchmarked against Lake Yunoko, a dimictic lake, fairly good agreement was obtained over a 4-yr period; thereby indicating it is suitably calibrated. In addition, to assess the effects of global warming on a lake ecosystem, changes in Lake Yunoko's water temperature/quality were simulated in response to an increase in air temperature of 2 - 4°C. Results indicate that such an increase will (i) increase thermal stratification in summer, which increases the nutrient concentrations in bottom water due to nutrient release from bottom sediment, (ii) increase the concentration of phytoplankton at the beginning of the autumn circulation period, and (iii) change the composition of phytoplankton species.

scholarly journals Litter mixing effect on decomposition rate and nutrient release: low quality leaves of coastal species

2021 ◽  
Author(s):  
Lili Wei
Keyword(s):  
Litter Decomposition ◽  
Decomposition Rate ◽  
Nutrient Release ◽  
Additive Effect ◽  
Nutrient Concentrations ◽  
Mangrove Species ◽  
Litter Bag ◽  
Litter Mixtures ◽  
Coastal Species ◽  
Litter Mixing

Coastal wetlands are among the most carbon-rich ecosystems in the world. Litter decomposition is a major process controlling soil carbon input. Litter mixing has shown a non-additive effect on the litter decomposition of terrestrial plants particularly of those species having contrasting litter quality. But the non-additive effect has been rarely tested in coastal plants which generally having low-quality litters. We selected three common mangrove species and one saltmarsh species, co-occurring in subtropical coasts, to test whether the non-additive effect occurs when the litters of these coastal species mixing together. We are also concerned whether the changes in the decomposition rate of litter will affect the nutrient contents in waters. A litter-bag experiment was carried out in a glasshouse with single and mixed leaf litters. A non-additive effect was observed in the litter mixtures of mangrove species Aegiceras corniculatum vs. Kandelia obovata (antagonistic) and A. corniculatum vs. Avicennia marina (synergistic). Whereas, the mixture of A. corniculatum (mangrove species) and Spartina alterniflora (saltmarsh species) showed an additive effect. The strength of the non-additive effect was unrelated to the initial trait dissimilarity of litters. Instead, the decomposition rate and mass remaining of litter mixtures were strongly related to the carbon concentrations in litters. Nutrient content in waters was dependent on the decomposition rate of litter mixtures but not on the initial nutrient concentrations in litters. Despite the behind mechanisms were not yet revealed by the current study, these findings have improved our understanding of the litter decomposition of coastal species and the consequent nutrient release.

In-situ disintegration of egg white gels by pepsin and kinetics of nutrient release followed by time-lapse confocal microscopy

2020 ◽  
Vol 98 ◽  
pp. 105228 ◽  
Author(s):  
Geeshani Somaratne ◽  
Francoise Nau ◽  
Maria J. Ferrua ◽  
Jaspreet Singh ◽  
Aiqian Ye ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Nutrient Release ◽  
Time Lapse ◽  
Egg White ◽  
Kinetics Of

scholarly journals Chemical Element Concentrations of Cycad Leaves: Do We Know Enough?

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 85 ◽  
Author(s):  
Benjamin E. Deloso ◽  
Murukesan V. Krishnapillai ◽  
Ulysses F. Ferreras ◽  
Anders J. Lindström ◽  
Michael Calonje ◽  
...  
Keyword(s):  
Root Zone ◽  
Chemical Elements ◽  
Incident Light ◽  
Leaf Age ◽  
Influential Factors ◽  
Nutrient Concentrations ◽  
Future Research ◽  
Nitrogen And Phosphorus ◽  
Element Concentrations

The literature containing which chemical elements are found in cycad leaves was reviewed to determine the range in values of concentrations reported for essential and beneficial elements. We found 46 of the 358 described cycad species had at least one element reported to date. The only genus that was missing from the data was Microcycas. Many of the species reports contained concentrations of one to several macronutrients and no other elements. The cycad leaves contained greater nitrogen and phosphorus concentrations than the reported means for plants throughout the world. Magnesium was identified as the macronutrient that has been least studied. Only 14 of the species were represented by data from in situ locations, with most of the data obtained from managed plants in botanic gardens. Leaf element concentrations were influenced by biotic factors such as plant size, leaf age, and leaflet position on the rachis. Leaf element concentrations were influenced by environmental factors such as incident light and soil nutrient concentrations within the root zone. These influential factors were missing from many of the reports, rendering the results ambiguous and comparisons among studies difficult. Future research should include the addition of more taxa, more in situ locations, the influence of season, and the influence of herbivory to more fully understand leaf nutrition for cycads.

scholarly journals Nitrogen, phosphorus, potassium, calcium and magnesium release from two compressed fertilizers: column experiments

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 1351-1360 ◽  
Author(s):  
M. J. Fernández-Sanjurjo ◽  
E. Alvarez-Rodríguez ◽  
A. Núñez-Delgado ◽  
M. L. Fernández-Marcos ◽  
A. Romar-Gasalla
Keyword(s):  
Nutrient Release ◽  
Geographic Area ◽  
Exchange Capacity ◽  
Nutrient Concentrations ◽  
Chemical Parameters ◽  
Npk Fertilizers ◽  
Nutrient Demand ◽  
Inner Diameter ◽  
Nitrogen Phosphorus ◽  
Controlled Release Fertilizers

Abstract. The objective of this work was to study nutrients release from two compressed nitrogen–potassium–phosphorous (NPK) fertilizers. In the Lourizán Forest Center, tablet-type controlled-release fertilizers (CRF) were prepared by compressing various mixtures of fertilizers without covers or binders. We used soil columns (50 cm long and 7.3 cm inner diameter) that were filled with soil from the surface layer (0–20 cm) of an A horizon corresponding to a Cambic Umbrisol. Tablets of two slow-release NPK fertilizers (11–18–11 or 8–8–16) were placed into the soil (within the first 3 cm), and then water was percolated through the columns in a saturated regime for 80 days. Percolates were analyzed for N, P, K+, Ca2+ and Mg2+. These elements were also determined in soil and fertilizer tablets at the end of the trials. Nutrient concentrations were high in the first leachates and reached a steady state when 1426 mm of water had been percolated, which is equivalent to approximately 1.5 years of rainfall in this geographic area. In the whole trial, both tablets lost more than 80% of their initial N, P and K contents. However, K+, Ca2+ and Mg2+ were the most leached, whereas N and P were lost in leachates to a lesser extent. Nutrient release was slower from the tablet with a composition of 8–8–16 than from the 11–18–11 fertilizer. In view of that, the 8–8–16 tablet can be considered more adequate for crops with a nutrient demand sustained over time. At the end of the trial, the effects of these fertilizers on soil chemical parameters were still evident, with a significant increase of pH, available Ca2+, Mg2+, K+, P and effective cation exchange capacity (eCEC) in the fertilized columns, as well as a significant decrease in exchangeable Al3+, reaching values < 0.08 cmol (+) kg−1.

In situ leaf litter production, decomposition and nutrient release of dry Afromontane trees

2019 ◽  
Vol 83 (3) ◽  
pp. 176-190 ◽  
Author(s):  
Emiru Birhane ◽  
Tekleab Desalegn ◽  
Fassil Kebede ◽  
Kidane Giday ◽  
Hadgu Hishe ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Nutrient Release ◽  
Litter Production ◽  
Leaf Litter Production
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