- Peter Kobor added an answer:Can anyone recommend literature on biogeochemical characterization of artificial lakes through dissolved nutrients?
Besides the collection of macroscopic invertebrates, I also measured dissolved nutrients during the assessment of a gravel pit lake. I would like to characterize the water of the lake using this data, but I've found no reference on methodology, yet. I would be grateful if anyone could give me advice to start out. Thank you in advance.
Thank you, Tatiana!Following
- Pete Manning added an answer:Why was the litter decomposition rate positively correlated with N content in the early stages of litter decomposition?
Many studies found that plant litter decomposition rate is related with litter concentration of nutrients ,such as N. But there is no a clear reason. I want to ask how the N concentration of litter influence on the litter decomposition.
Because nitrogen lmits microbial growth.Following
- A. R. Karbassi added an answer:Can someone suggest a review about "pore water chemistry" in marine/lake core sampling?
Especially, biogeochemistry or hydrogeochemistry in pore water of marine core deposite!
You may see the following links:-
- Melissa Gaste Martinez added an answer:How important is iron and sulfur in the ecosystems you study?I just came across a paper that is very interesting discussing iron - sulfur dynamics in the presence of iron reducing bacteria. In the Everglades, the system I am interested in, iron concentrations are relatively low (generally) while in some areas sulfur (as sulfate) is extremely high.
I'm sory, but I not studu this components. I study stable isotopicFollowing
- Clinton Rissmann added an answer:Why is the ratio of aqueous sulfate to chloride in aquatic systems related to sulfate reduction?
I am trying to understand what mechanism(s) account for the fact that the [SO42-]:[Cl-] ratio in water can be indicative of the level of activity of sulfate-reducing bacteria in aquatic ecosystems.
Hi Meredith, I relate to C. Brannon Andersen's answer. Having some understanding of the [Cl] would be very useful. If there is data from the lake from other studies you could compile an average or median [Cl]. Here in New Zealand we see considerable variation in freshwater Cl concentrations depending on the distance from the coast. However, under stable conditions the Cl concentration is usually very consistent for a given lake. With respects to redox assignments I use a field portable colorimeter to measure Total Sulfide (TS), a handheld meter for D.O., Eh, SpC, pH as well as taking samples for the main terminal electron accepting species (TEAS: NO3, Mn, Fe, SO4). If you were interested the redox assignment workbook of Jurgen et al. (USGS) is useful. Measuring total sulfide helps to discriminate as to whether FeIII or SO4 reduction is the dominant terminal electron accepting process. Kind regards, ClintFollowing
- Kenneth M Towe added an answer:Are there cost-effective ways of capturing and harvesting 'biogenic' combustible gases from seeps in the seafloor?
In the current 'climate change' syndrome, we are constantly looking for ways of ridding the atmosphere of accumulating radiative gases (so-called 'greenhouse gases, GHGs': H2O, CO2, and CH4). Over the last 3 decades, we have found thousands of locations in the seafloor, where one of the strongest GHGs is escaping, namely methane, CH4. These are active gas vents, or seeps, which are easily tracked acoustically, their manifestations known as mid-water gas plumes, or just 'flares'. I have recently found a way of harvesting such gas seepage, with a device (or system) called SUMECO: "submarine methane collector" (see my latest written contribution, in my profile). I belive this to be a viable and cost-effective way of harvesting methane from the seafloor, for use as a resource.Following
- Pascal Badiou added an answer:What is the best way to quantify the phosphorus contribution by in-lake biogeochemical cycling?
We know the internal P loading is a big contributor to algal bloom for many eutrophic lakes. But there is a lack of studies that can identify and quantify the amount of P from sediment resuspension in a eutrophic lake. Any idea or suggestion?
Another potential for examining this issue is to look at the maximum phosphorus sorption capacity of the sediments as well as the equilibrium phosphorus concentration. These will allow you to determine if the sediments in your system still have the capacity to bind P and at what water column P concentration your sediment acts as a sink or source of P. This will only identify the P fraction that is being released or taken up through biogeochemical interactions and will not provide information on P resuspension.
In terms of P resuspension there are a number of studies that have examined the impacts of benthivorous fish and wind driven sediment resuspension on TP in the water column.Following
- Amokrane Athmane added an answer:Are there any national-scale (US) land-use regression models for CO or SO2 that are publicly available?
I'm thinking of something along these lines:
But for SO2 or CO
Thanks in advance LUR experts!
Not to my knowledge, and also this is not my area of research, mine is soil parameter.Following
- Mark Krause added an answer:What is the optimum weight of carrier based inoculum to apply and the frequency of application for cleaning 1ha soil contaminated with 4-5% crude oil?
The carrier is charcoal. It contains a consortium of efficient bacteria (10 to power 8-9 CFU/g). The soil was contaminated 7 years ago. The soil is clay loam, pH 8.2, low N, P and organic matter content.
At that level it is completely dependent upon the bacteria. If the bacteria are aerobic it is doubtful that you will get treatment at that level of contamination. You might look into an alternative:
Look at the Piranha mix. We have successfully used their product to treat crude oil in the 5-10% loading range on soil; I have never found another product that would approach that level. it also has the added benefit of a single application and no further tilling.Following
- John R. Helms added an answer:Does filtration of sea water result in loss of dissolved gaseous mercury (DGM) species (Hg0 and DMHg)?
Measurements of dissolved gases (oxygen, CFCs,..) in sea water samples is usually done on unfiltered samples, and tedious protocols need to be followed to avoid any bias (must be first sample to be taken, quickly after collection, no bubbles, overflow bottles 3x volume,...). DGM measurements are done on both, filtered and unfiltered samples. Could filtration result in any loss of Hg(0) or dimethylmercury?
The issue isn't filtration per say as of course they are not particles. It's the sparing solubility and significant vapor pressure of the analytes. Under vacuum filtration conditions they can partition into the headspace and be evacuated by the vacuum system. That's why using capsule filters under positive pressure (or esp. gentle gravity pressure with no pump cavitation to generate bubbles) is recommended, *if filtration is needed*. If measurements are made immediately, there is no reason to filter. If samples are to be stored, they need to be preserved in a way that preserves the Hg speciation somehow and sometimes filtration is used to remove microbes.Following
- Alexandre Castagna added an answer:Which method(s) can I use to smooth stacked curves of oxygen isotope?
I want to use Cramer et al. (2009) raw data of oxygen and carbon isotopes for a very specific time period (around 2 Ma long) to compare it to my oxygen and carbon isotopes from terrestrial record. My aim is to show that my site is affectd by global factors by comparing Cramer's data with mine. I don't have the same sample resolution as Cramer's: he has about 1000 data points while I have about 300. How can I solve the problem of difference in data resolution? Which methods would you suggest to address this issue?
I also would like to statistically compare my data with Cramer's, but my data is terrestrial so the oxygen isotope values are much lower (around -7 per mil). I would like to be able to compare the trends, not the actual values. Would anyone know which test(s) I could use?
Very nice Julie,
I would suggest to you R as very flexible and powerful tool and you can always count on its large community of users to help you out. There are a number of e-mail groups dedicated to specific research areas with R. Good luck with your research.Following
- Amit Kumar added an answer:How can I make an anaerobic environment in a 250 ml tight bottle contain Soil:water(1:1) to get methane ?
Degradation of carbon at a certain temperature and humidity evolve methane. Only methods are require to maintain anaerobic Environment in small bottle.
Siyue Li...after conformation i will let you know ...but we can measure ch4 concentration ??Following
- Per Hagelia added an answer:Can anyone recommend updated solubility constants for minerals associated with ARD?
I basically need access to reliable solubility constants of sulfates which are associated with acid rock drainage, acid sulfate soils and acid mine drainage.
Perhaps someone has made a recent compilation?
Thank you both for swift response.Following
- Harald G. Dill added an answer:Dear fellows, Do you know any comprehensive review about soil weathering indexes?
Weathering indexes are useful to estimate the intensity or the duration of a weathering process in geological materials as soils. But what are the pros and cons? What are the methodological issues about these indexes? And, finally, why aren't they popular? For soils there are two interesting indexes: the Ki (Silicate to Al-oxides ratio) and the Kr (Silicate to oxides ratio). In simple words: How intenser and/or longer the weathering process, more intense the loss of silicates will be and more oxides will remain in the soil. Therefore, higher the Kr or Ki ratio. As a rule of thumb, soils with Ki < 2 (devoid of 2:1 phyllosilicates) are the highly weathered ones. The highly weathered soils from Brazil very often presents Ki and Kr < 1.
Dear Mr. Sobrinho,
the approach you will have to take, strongly depends on the mineral assemblage of your weathering profile. I have used clay minerals and heavy minerals. The latter group is rather sensitive and even can show you the intensity by the crystal morphology (see file attached). In your environment, newly formed APS minerals may also be of help (Aluminium-Phosphat-Sulfate minerals/ crandallite group), which can be used in combination with sequioxides (Al oxides) and phyllosilicates (kandite-group + halloysite). The following paper may give you an introduction into the matter
DILL, H.G. (1998) A review of heavy minerals in clastic sediments with case studies from the alluvial fan through the near-shore marine environments.- Earth Science Review, 45: 103-132.
DILL, H.G. (1995) Heavy mineral response to the progradation of an alluvial fan: implications concerning unroofing of source area, chemical weathering, and paleo-relief (Upper Cretaceous Parkstein fan complex / SE Germany).- Sedimentary Geology, 95: 39-56
DILL, H.G. (2001) The geology of aluminium phosphates and sulphates of the alunite supergoup: A review.- Earth Science Reviews, 53: 35-93.
Should you have further questions feel free to contact me on this matter.
Harald G. DillFollowing
- Margarete Maria Kalin added an answer:Is somebody working in humic substances of riverbed sediments and their interaction with metals?
Im working in La Matanza River and study the interaction between humic substances and metals and their mobilization influenced by dissolved organic mater in water column. I want to modelize it
check out Christian Steinberg work it is extensive in this area, including I believe a book on it.
- Victoriano Urgorri added an answer:Does anyone know what this Marine Organism is?
It was found at in an Irish marsh exposed to fresh and marine water (depending on the tide) and was living on top of mud. It is not flat (picture can be deceiving) and is shaped like half a lemon. It is about 2mm long. Looks like some sort of slug, but I have no idea where to start. When alive it moves like a slug across the surface of the mud. The one in the pic is preserved in alcohol. Any help would be very much appreciated!!
Dannielle, I think it's a juvenile of Alderia modesta (Lovén, 1844) a gastropod mollusc (Order Sacoglossa; Family Limapontiidae). This little sacoglossan (10 mm long) is associated with Vaucheria in saltmarshes and it is resistant to salinity changes. You can to check if the animal has a radula.Following
- Harry ten Brink added an answer:Can anthropogenic nss SO4 contribute to more CCN over Chichijima than that of marine nss SO4?
Which sulfate (anthropogenic or marine biogenic) will contribute to more CCN over a remote marine island in the western North Pacific.
I gave a reply 2 days ago, but it is not in the list.
1. Regional models give an estimate of the concentration of sulfate at the site. Then you can use a formula of Doug Lowenthal to estimate the CCN number. Greg(ory) Carmichael of University of Iowa
2. Natural sulphate can be assessed from an isotope measurement; perhaps there are data at your site. Example is the work of Len Barrie in Canada
3. I checked the site: this is NOT REMOTE: it is in the east-Asian plume?!Following
- Vahid Chamanara added an answer:What is the correct approach in calculating the average pH values measured by a combined electrode?Is it a directed ordinary mean or taking the anti-log values at first then getting the average and return to the log values again? I think if we measured it by electrode that is fair to calculate the ordinary mean from the pH values but if we measured the H ion activity which is so difficult then we can use the anti-loge approach. Am I correct?
Thank you guys,
can we use the mean values in the SPSS output report?Following
- Igo F. Lepsch added an answer:Does anyone know how to stain (blue, red or other) silica-phytoliths (or biogenic opal)?
Plant silica bodies (also callled silicophytoliths and plant opal) can be extracted from plant tissues or from soils. I wonder about the best method to stain these small particles in order to visualise and photograph them better under the petrographic microscope.
Já experimentamos colorir com Violeta Genciana ( methyl violet ) e obtivemos bons resultadosFollowing
- Nicolai S Panikov added an answer:Which is the best way to express amount of substrate and CO2 respiration rate?I have been reading many papers about adding glucose, sugar or other complex substates (cellulose, litter, crop residues) to soil to analyze soil organic matter decomposition and soil respiration. The confusing issue I ran into was: how to express the amount of C from substates added to soil? For example, some report the ug or mg C per g soil, and some simply use the percentage of C based on the soils used. For the respiration, some use the ug CO2-C per g per h, some ug CO2-C per g per day or week, and some even use mg CO2-C per g per h/day/week.
Other than the inconsistent report of the amount of substrate, different papers have different experiments periods or lengths. I am wondering if it is better to express the amount of C from substrates using a time scale? For instance, two papers report the same amount of 1000 ug C per g soil, but they have different duration, let's say 10 days and 100 days. By using the time scale, we see the C addition is completely different: 10 ug C/g soil/day vs 100 ug C/g soil/day. But I don't know which way is best for respiration.
Does anyone agree or disagree that we should propose a common way to specify the expression of substrate input and respiration? Feel free to leave your comments and suggestions below. Thank you.
The respiration rate must be expressed as amount of CO2 (ug or mg or g of CO2-C or mmol of CO2) per amount of soil (g, kg) per unit time (min, hr, day or even week/month/year).
If you see the published data with the missed time units, then it is qualified as error made by authors and editors.
What is better, mg of CO2-C or mmol of CO2? In a C-balance studies mass units of carbon are better. In the studies of metabolic pathways (e.g. degradation of PCB in soil), the molar concentration is preferable.
What is better, ug, mg or g of CO2? g or kg of soil? hr or day? No strict rules, just make your numbers easy to read. There was a tendency to unify the units to international standard but it is not always justified.
Finally, per g of soil or per m^2 of soil surface? Depends on technique you use, whether you measure a flux of CO2 by chambers or incubate few g of soil in a vessel.Following
- Asmeret Asefaw Berhe added an answer:Does soil erosion (e.g. tillage erosion) enhance or decrease the CO2-emissions and C-balance of agricultural landscapes?
I'm aware of the discussion of e.g. Van Oost et al. and Lal et al., however I would be interested in direct field measurements/experiments showing the main environmental drivers for the one, or other development.
It depends on the specific landform position from where erosion is happening (i.e. soil and C stock, erodibility of the soil), the amount of free and occluded carbon (i.e. aggregate protected C) or buried carbon you had in the given soil profile, and intensity of the erosion process. Some studies have shown that up to 20% of C in eroded soil/sediment (i.e. C in sediments mobilized from eroding slope positions) can be lost due to oxidative decomposition during the erosional transport or soon after deposition in downslope depositional landform positions.
check out the papers below for more info;Following
- Stefania Squadrone added an answer:What could be the possible mercury uptake mechanism in microalgae?
I'd like to know the processes involved as to how algae uptakes mercury
There is a very interesting paper by Garcia Bravo on this topic, the reference is Environmental Pollution journal 2014,vol192, pp 212-215, that suggests facilitated transport of methymercury as additional uptake mechanism. Best regards, stefaniaFollowing
- Raffaele Bernardello added an answer:What are the relative impacts of diapycnal mixing vs surface mixing layer deepening on sea surface pCO2?
Here we have only calculated the impact of diapycnal fluxes on the sea surface pCO2 - however significant entrainment of deep water into the surface mixed layer will also impact on the sea surface value of pCO2. Given this change will essentially be a "shock" when compared to the much slower changes due to diapycnal fluxes - has anyone considered the relative timescales of the growth (ie. DIC/ NO3 utilisation) and equilibration on pCO2 - and whether it is even important when compared to the slow diffusion of CO2 across the sea surface?
if you haven't read it already, you might find this paper (and references therein) relevant to the subject:
Sallee et al., 2012. Localized subduction of anthropogenic carbon
dioxide in the Southern Hemisphere oceans. Nature Geoscience, DOI: 10.1038/NGEO1523Following
- Mingda Wang added an answer:How the Asian speleologists record the abrupt events in N Atlantic?
Abrupt events, such as YD and H1, etc, have been recorded in cave deposits (Wang et al.,2001 and so many papers). However, could you tell me the mechanism behind it? What is the bridge for the signal transmit? The atmosphere or the ocean current (THC).
Could you share some references to support the idea? Thanks. By the way, could you give some specific details about the atmospheric transmission? For example, westerlies or others? Thanks.Following
- Fikrat Hassan added an answer:Does anyone know of a paper discussing nutrient starvation in an ecosystem?I am looking for a paper which discusses the potential negative effects of extreme nutrient limitation. The majority of the literature focuses solely on enrichment or excessive loading of nutrients. While eutrophication can be harmful for ecosystems, I assume that nutrient starvation could also be bad, unless it is an adapted ultra oligotrophic system. Just wondering if anyone has stumbled upon any papers.
may be the following paper useful for you:
Dataset: Laboratory study on the effects of nutrient enrichment on a phytoplankton population in Sawa Lake, Iraq
Fikrat M Hassan, Hussein A Al-Saadi, Foad M AlkamFollowing
- Abhijit Chakraborty added an answer:Are there any methods that offer specific signatures for specific bacteria in the Archean?
Since the C-Isotopes are not really that helpful, I was wondering if anyone has some suggestions on this. Is it possible to distinguish, let's say, cyanobacteria from anoxygenic photoautotrophs?
Thanks for the Replies,
Thank You very much Dr. Chi Fru. I would like to mail you on more detailed case specific issue of my study area.Following
- Diego Fernan Wassner added an answer:How can I measure terpenoids in resin?What affects the composition of resin? Is the ratio of sesquitepenoids and diterpenoids in a resin always the same, or does it change due to external or internal influences on the plant?
I worked with dipernic resin from leaves an steams of grindelia chiloensis, a native shrub of patagonia.
Resin extraction was realizad using dicloromethane in a soxlhet apparatous, and then refined. Composition was determined by gas chromatography.
I can send a paper with methods.
- Luiz Carlos Cotovicz Junior added an answer:What are the thresholds of DO supersaturation that can make possible the spontaneous bubble formation?
The high primary production at hypertrophic environmentals can produce oxygen at so high levels that spontaneous bubble formation can occur. What are these DO thresholds (depence with temperature, etc)? Can someone indicate to me readings about this theme? Thank you.
Thank you very much. Your answers help me and I think that exists oxygen bubble formations drived by phytoplankton blooms (strong supersaturation conditions) at my study area. Best Regards!Following
- Sarat C. Tripathy added an answer:After 24h primary productivity incubation, in the 6 layer's Pb data, the maximum one should be the pbopt or pbmax?What is the difference between pbopt and pbmax?
PBmax is measured when you carry out Photosynthesis-Irradiance (PE) experiment on same phytoplankton community (i.e., from a single depth) by exposing them to different light intensities. This is usually done with the help of a photosynthetron (specially designed incubator). Whereas, PBopt is the optimal PB observed in the water column, where the phytoplankton community may or may not be the same (mostly not same). So the answer to your question is PBopt.Following
- Jim R. Jones added an answer:How does one collect pore water samples from coal seams and is there any standard protocol?
Aerobic and anaerobic conditions.
Presumably the coal seam is not saturated with water. If it were, then a core will fill with water simply due to the pressure gradient. For an unsaturated coal seam, using a double action pressure swing to first locally infuse the seam with water, then extract it, will obtain enough for later analysis. A device will need to be invented for this purpose to lower into the core, however. The alternative is to extract a core sample and then analyse in the laboratory.
Jim R. JonesFollowing
Biogeochemistry is the scientific discipline that involves the study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment (including the biosphere, the hydrosphere, the pedosphere, the atmosphere, and the lithosphere).