Aquatic Ecosystems

Aquatic Ecosystems

  • Florian Koch added an answer:
    Are you aware of studies on naturally (acidic) vs. anthropogenically (acidified) low pH estuaries?

    The question revolves around the concept of acidification of estuaries, as an ecological process which may be induced by human activities. In tropical conditions, high rainfall, heat and high primary production and specific geological settings may determine soil acidic conditions, which may control relatively low pH conditions in estuaries (i.e., in the lower tract of hydrogeographic basins). I am looking for the available literature and an overview/discussion on the state of art of this topic.

    Florian Koch · Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research


    IN my old lab they are spending a lot of time with exactly these kind of questions.  I would look at the Christopher Gobler’s Laboratory page at Stony Brook University and his recent publications.  Also his PhD student Ryan Wallace has done a lot of work in Jamaica Bay, Long Island Sound and many of the Islands numerous barrier island estuaries with regards to pCO2, alkalinity and DIC measurements in addition to numerous other environmental parameters.  Check out their lab page and publications and maybe shoot them an email.

    Cheers and good luck.

  • John J. Hains added an answer:
    Does anyone know of techniques of publications for gap filling dissolved oxygen data in freshwater habitats?

    We are currently using D-Opto dissolved oxygen sensors in marsh habitats to measure continuous seasonal changes in dissolved oxygen.  Power issues and occasional sensor issues leads to gaps in our data set, which we would like to fill in order to conduct the appropriate time series analysis.  Unfortunately, literature searches have yielded little information regarding methods for gap filling dissolved oxygen data.  For this reason I am reaching out to the Research Gate community for advice.  Thanks :)  

    John J. Hains · Clemson University

    What is the frequency of measurement during normal operation? How long are the gaps? You need to provide a little detail. 

  • Sandipan Gupta added an answer:
    Is Mystus gulio (locally known as Nuna Tengra) a threatened native estuarine catfish?

    Yes. According to IUCN (2000) Mystus gulio (locally known as Nuna Tengra) a threatened native estuarine estuarine catfish, enjoys a high consumer preference fish in many Asian countries including Bangladesh.

    Sandipan Gupta · Central Inland Fisheries Research Institute

    The ratio with which Mystus gulio was stocked is not clear from this paragraph. To analyze this I think few factors to be considered, i) the feeding niche of the fish species poly cultured, ii) stocking density. As per the information provided in T2 and T3 Mystus gulio was cultured with O. niloticus and R. corsula (with varying stocking density); so how can it be concluded or rather to be compared; for this you will have to culture Mystus gulio with O. niloticus (in one experiment) and with R. corsula (in another experiment). Then one can compare the growth difference.

  • Geraldina Signa added an answer:
    Can anyone identify this tropical large goby?

    This specimens was catched in a channel passing through a mangrove forest in Kenya and is quite large (Standard lenght 17 cm). 

    Geraldina Signa · Università degli studi di Palermo

    thanks a lot to both of you!

  • Gustavo Henrique Pereira Dutra added an answer:
    What are the major causes of fish mortality in net cages?

    Would you any body provide me possible answer? Thank you.

    Gustavo Henrique Pereira Dutra · Prefeitura Municipal de Santos, São Paulo, Brazil

    Dear Mohammad, the main cause of death in marine aquarium is parasitic (Oodinium and Cryptocarion irritans, as dinoflagelates and protozoa, respectively; and monogenea trematoda). Brazilian Hugs

  • Jorge Tornero added an answer:
    What types of weights do you use on board research vessels at the sea?
    I need some information on weights for marine investigations. Can you inform me - what types of weights do you use aboard research vessels at the sea? Are there any weights with resolution 0.1 g or higher? We used Pols with such resolution long time at PINRO, but now Pols is not exist. I will grateful if you can provide model name and producer (and site where it will be possible to see it).
    Jorge Tornero · Instituto Español de Oceanografia

    Here in our lab at Cadiz we own one Pols scale with 0.01/0.02 g resolution, up to 0.130 kg.

    This scale, under our usual sea conditions and ships performs reasonably well and we use it mainly to weigh anchovies and sardines and their gonads as well as many other species when appropiated. 0.1 g resolution is also used, mainly for mackerel, horse mackerel and friends up to 1.3 Kg I seem to remember (with triple resolution range, 0.1, 0.2 and 0.5 g)

    Unfortunately Pols not longer exists (was, among others, phagocited by Marel) and it looks like Marel is not much interested in producing "high resolution", scientific grade scales. They are stuck to 3000 scale divisions so the highest resolution you can get from them is, as P. kainge has pointed out before is 0.1 g up to 0.3 kg.

    And yes, they don't list the 0.1 g scale in the web but it exists for sure. We are on purchasing two marine scales for the lab this year and this ws one of the candidates. By the way, the actual name of the model is M2200 with platform PL2220, 0.1 g 0-300 g

    Best regards

  • Purushothaman Paramasivam added an answer:
    What's the genetic mechanisms of sex reversal in crustacean(crab)? Do any key genes play a pivotal role?

    I know AGH is a key gene for sex characteristic of male in crustacean.but i want to know the mechanism of sex determination of crustacean,especially in crab.

    Purushothaman Paramasivam · Central Marine Fisheries Research Institute

    evan i have doubt. sex reversal is their in penaeid shrimp's life cycle??. but same time i have seen some specimens having both organs but surely i don't know. whether its right or not.

  • Nadezhda Ivanovna Yermolaeva added an answer:
    Does anyone have any experience in creating thermal refugia patches in standing water?

    I would like to investigate the use of thermal refugia by non-native crayfish species in the UK, by setting up tanks with a "patch" of water which is a constant temperature, whilst the rest of the tank varies naturally. Basically trying to mimick a groundwater upwelling, but on a small scale.  

    Preferably, the thermal refuge area would not be enclosed and used as a natural shelter by the crayfish. 

    Any ideas of ways to design this type of tank would be greatly appreciated!

    Nadezhda Ivanovna Yermolaeva · Institute for Water and Environmental Problems (IWEP)

    If you want a well-defined temperature in the refuge - you need a thermostat for the aquarium.
    If you just need to raise the temperature (relative to the rest of the tank), it is possible to tighten the part of the surface water by the black film. To reduce the mixing under the film can to be create artificial macrophytes - on a clothesline to hang strips of polyethylene film.

  • B. Manikandan added an answer:
    Which statistical methods can be applied for analysis of time-series data on percent cover of benthic forms in a coral reef ecosystem?

    I had collected data on the percent cover of benthic forms including corals, macroalgae etc. continuously for 2 years in 2 different study sites. Analysis of the results revealed short term proliferation of macroalgae in the study sites with corresponding decrease in the percent cover of other benthic components. Kindly advise me what statistical methods can be applied to suitable interpret the results.

    B. Manikandan · National Institute of Oceanography

    Jose @ Thank you for the reference. I will look in to it.

  • Jack Edward Lee added an answer:
    How much Ammonia (NH4) is deposited into freshwater from the atmosphere?

    I know this is question highly depended on geographic location, but is there an average deposition of NH4 from the atmosphere into a body of freshwater? I'm specifically looking for a reference that gives the amount of NH4 deposited into a litre (or m2- surface area) of water per year. I'm looking for references ideally from the UK. 

    I'm specifically looking for references that report atmospheric deposition, independent of dust/rain/bird droppings etc. 

    Any help or advice pointing me in the right direction will be very much appreciated.

    Jack Edward Lee · University of the West of England, Bristol

    @Chandravadan Trivedi 

    Atmospheric NH3 deposition is a really big problem.

  • Geoffrey Marchal added an answer:
    Does anybody have any methods/ tips/ helpful advice for remediating a coastal sand dune?

    This is for a final year project so I can't do anything too big. I'm looking at replanting vs seeds with and without alginate gels so far. The area is not huge ~570m2, but the aim is basically to get an idea if a method looks like it will provide faster regeneration.

    I know not a lot has been done in this area so any helpful ideas would be appreciated.


    Geoffrey Marchal · Technical University of Denmark

    I´m not an expert on that. But I guess you will have more chance by replanting bushes with fast growth like Atriplex halimus. It is a fast growing halophyte bush.

  • Caterina Milillo added an answer:
    Is there anyone who is working on eDNA for aquatic plants in a freshwater ecosystem?

    How can we identify the species from the DNA cocktail we are getting as eDNA from water?

    Caterina Milillo · Ministero dell'Istruzione, dell'Università e della Ricerca

    I have never worked with e-DNA, but it is a subject that interests me. Try to look at this link. It is a review on its applications:

  • John R. Helms added an answer:
    What's the source of short chain alkanes?

    Zigetang Co is a meromictic endorheic saline lake without any glaciers in the catchment on Tibetan Plateau, which is directly located at the boundary of the Indian monsoon. The short chain n-alkanes C15, C16 and C17, likely derived from aquatic algae, plankton and photosynthetic bacteria, dominated most of the lake sediments. Howerver, we are not sure how to explain the source of these short chain alkanes. Do you have some ideas or some similiar papers discussing the short chain alkanes? Thanks a lot.

    John R. Helms · Morningside College

    In addition to some of the earlier advice, there is an extensive literature dealing with sources of alkanes and other lipids for use as sedimentary and geological biomarkers. It might be worth querying your data using the "terrestrial aquatic ratio (TAR)" biomarker index and the "carbon preference index (CPI)" and compare with previously published values to determine source, diagenetic state, as well as possible anthropogenic contamination.

  • Richard Chadd added an answer:
    Which caddisfly species are characteristic of English winterbournes?

    There is a current debate over how to properly characterise winterbournes on chalk geologies in ecological terms. There are some key species already well documented (e.g.the mayfly Paraleptophlebia werneri Ulmer), but I'm not so sure of the key caddis species. Does anybody have any ideas? Notionally, it will allow us to distinguish ephemerality caused by abstraction pressures against naturally ephemeral streams.

    Richard Chadd · Environment Agency UK

    Hi Terry,

    I had a look at Andy's publication in British Wildlife (October 2009) as directed by Paul. Some of the key species were Limnephilus vittatus, L. bipunctatus & L. centralis.



  • M. Selvanayagam added an answer:
    What is this caddisfly (Trichoptera) form? And is it really an indicator of freshwater quality?

    I found this larvas near side of freswater located at North of Turkey (East of Blacksea Region) in spring 2014. So there are many of family and form of caddisfly. Is it possible to determine family and form of its? And very few study indicate that there is a relationship between water quality and its living condition and "most types of caddisflies are pollution sensitive. Caddisflies are a good indicator of water quality because they live within a diversity of habitats. However, some types that are widespread, can tolerate pollution and environmental stress".

    Even if this species one of the indicators of water quality, I can't guess whether freshwater have good quality or not because some of forms can tolerate pollution and environmental stesses.

    Have you any idea about this issue?

    M. Selvanayagam · Loyola ICAM College of Engineering and Technology (LICET), SENESCYT,Ecuador, American University of Sovereign Nations,Arizona

    yes Ttrichopteran are good indicators of  water quality and that why they are included in EPT for water quality assessment. There are  different species, some of them  case makers while others non case makers .The larval forms  could be identified based on the   presence of three  dorsal plates with out hump family-Hydropsychidae, with two dorsal plates with out any hump as in  family Brachycentridae,,with dorsal and lateral hump in family Odontoceridae.

  • Tatiana Chuzhekova added an answer:
    Is there any way to possibly warm a stream a couple of degrees to determine the effects of climate warming on Benthic Invertebrates?
    Limited material preferable, power equipment unfortunately not a viable option
    Tatiana Chuzhekova · Saint Petersburg State University

    Dear Jeremy, if your question is still actual. Couples years ago in Duisburg-Essen University was held an experiment on nearly same topic. But they studied natural warming in streams with shading and with out it.  So the shading gave the difference up to 4 degrees. I don't know if they have published the results of this research, but I think that you could contact Dr. Armin Lorenz and ask about it (the link is bellow).

    Best  wishes,

  • Joydeep Pal added an answer:
    How does the N/P ratio control the phytoplankton in shrimp ponds?

    What is the total nitrogen, total phosphorus, dissolved inorganic carbon and dissolved inorganic phosphorus? How does the ratio of N/P control the phytoplankton in shrimp ponds? Can someone suggest literature about this? Thank you.

    Joydeep Pal

    Please download the paper in the link provided.

    I assume it will definitely help you a lot in understanding the basic knowledge about your query in a broader way.

    Prof.Tang in right in pointing out the Redfield ratio it is a crucial factor for the phyto plankton and marine autotrophs. 

  • Fernando Rey added an answer:
    Are there any ideas on how to feed broodstock of Pacific white shrimp from wild pond to hatchery?

    I am planing to do a genetic improvement project for white shrimp. The stage of transportation broodstock white shrimp from wild pond to hatchery until eyestalk ablation is like a gambling. Some time the success ratio is below 20%。Now we are suffering a high broodstock mortality in the hatching tank. Is there anyone have a better success experience for feeding broodstock during this pre-maturation stage?

    Fernando Rey · California Science Center

    The following is my feeding protocol when conducting  GENETIC selection for Litopenaeus vannamei broodstock:

    When starting with wild broodstock acclimate them to the new water condition prevailing in your maturation tanks (salinity, temperature and pH) for at least during 6 to 8 hours. Better to start with shrimp raised in your grow-out ponds at a density of 10shrimp/M2 since mortality decreases considerably. When harvesting your shrimp select the largest 200 animals and continue raising them for another 4-5 months. Feed them with pelleted formulated shrimp feed (crude protein content between 40-42%); stocking density: 5 animals/M2. When harvesting those shrimp select the largest 100 animals and stock them in your maturation tanks at a density of 2 shrimp/M2. Then feed them with fresh polichaetes (50%), plus fresh squid/fish and clams the other 50%. Ideally you should stock them in your maturation tanks at a male-female ratio of 2:1 

  • Virginia Garcia-Millan added an answer:
    What are the best remote sensing techniques for mapping submerged aquatic vegetation in estuaries and river mouths?

    Can eelgrass colonies be detected from satellite altitudes?

    Virginia Garcia-Millan · EFTAS Fernerkundung Technologietransfer GmbH

    In order to study vegetation, optical sensors might be the most appropriate for you. However, as Chavez and Mahmud said, the transparency of the water you are observing is a limiting point for your study. Turbidity might mask what you are trying to see.

    If the water under study allows you to see the vegetation underneath, I recommend you 2 types of sensors: if you need to study any plant function (i.e. chlorophyll content, NPP, pigment concentration, species diversity, etc.), I better recommend you a hyperspectral sensor. If you only need to know the distribution of the vegetation communities, maybe it is enough with aerial CIR photos.

    Another key question is the resolution you need. If you don't need very high resolution, you might also use sensors of mid-spatial resolution, such as Landsat, which can be downloaded for free.

    It is always a trade-off between sensor features and price. If you provide more details on your research maybe we can better assess you.

    Good luck!


  • Dominique Davoult added an answer:
    What are some of the impacts of floating structures to the marine environment?

    What are some of the impacts of floating structures/ buildings to the marine environment and how can design seek to prevent the damages to its coastal surroundings?

    Dominique Davoult · Pierre and Marie Curie University - Paris 6

    I think that floating structures, mainly fixed ones can have negative impacts on the benthic environment, due to shading first and then maybe to the local decrease of currents (e.g. tidal currents) that could change the rate and size of deposit of fine sediments and/or organic matter

  • Nathalie Niquil added an answer:
    What are your thoughts on using Large Fish Index as an ecosystem health indicator characterizing the food web ?
    Your answers will be usefull in the discussions on finding common indicators in Europe for monitoring food web health in marine ecosystems. LFI is for example monitored within OSPAR as the percentage of fish > 40 cm when performing a bottom trawl. The idea beyond is that food webs are shortened by overfishing. What do you think of it as an indicator not only of the fish community but also of the whole food web. Is this indicator sensitive to other pressures than fishing ? How could this indicator be modified for a better food web use ? Would it make sense to apply it to benthic species and especially invertebrates ?
    Nathalie Niquil · French National Centre for Scientific Research

    Thank you very much for these answers. They are all very compmlementary !

  • Benjamin Casper added an answer:
    Which levels can be distinguished in hydrological units of an urban river delta?

    The hydrological units of administration (e.g. Drainage Departments, etc.) often do not correspond with the planning units or administrative units (New Orleans synchronised them after Katrina). Which levels should be distinguished in a spatial sense, with the river basin being the biggest scale?

    The hydrotechnical units of the drainage of deltacities are set by human planning. Do the engineered units of control of water correspond with the hydrologic-ecologic understanding of  waterflows?

    Benjamin Casper · University of Cologne

    Dear David and Shabaz,

    thanks for your answers. I realised the different perspectives of different disciplines are an important factor when talking about water in a planning context. It is very helpful to use the shift in perspective to understand demands of different disciplines for decision-making in their "units", even this decisions should increasingly be done transdisciplinary.

    I try to come to an inclusion of viewpoints to form a framework for a delta-city like Bangkok to transform for a living with water. Therefore I will check how your mentioned units can dock on the framework. The IWRM-issue is a big challenge and definitely needs co-production of knowledge, I will read your article, thanks a lot.

  • Sundar S added an answer:
    In what way will invasive plant and animal species affect native animal fauna of the freshwater aquatic ecosystems?

    Aquatic biodiversity is increasingly affected and declined through various factors including increasing of temperature due to climate change, anthropogenic effects, invasive species slowly adapted in a particular environmental condition and replaced native species etc. 

    Sundar S · Pondicherry University

    Thanks Dr.Julian for valuable answer.

  • Joe Silke added an answer:
    Does mussel aquaculture have an impact on wild fish populations?

    Rope mussel aquaculture has reached its maximum potential of the west coast of Ireland but as a consequence does the reduction in phytoplankton species have an impact on wild fish (particularly salmonids) species down the food chain?

    Joe Silke · Marine Institute

    The mussel industry on the west coast of ireland continues to grow year on year which would suggest that saturation has not been reached, BIM have proposed that shellfish aquaculture is one of the key areas for future development because of its low impact and economic potential in Ireland. Mussel aquaculture is unlikely to have anything other than a tiny localised zone of impact considering the small footprint of these farms on the overall available coastal zone. Ropes of mussels also recycle nutrients for further phytoplankton production and provide shelter to many fish communities, providing surfaces for rich epiphyta and epifauna as sources of food. These bottom up impact on the food chain are extremely complex issues, in this case it is likely to be very localised with minimal impact on wild migratory fisheries.

  • Vesela Yancheva added an answer:
    Does anyone know if NRR assay can also be applied on freshwater mussels (for example, Unio sp.)?

    Most of the data on NRR assay has been performed on saltwater mussels (Mytilus sp.). This assay is performed on haemocytes as haemolymph (between 0.1 and 0.2 ml) is collected from the posterior adductor muscle using a 1 ml syringe containing an equal volume of physiological saline solution. Therefore, I am wondering what solution I should use instead? Will freshwater be sufficient? Thanks a lot in advance.

    Vesela Yancheva · Plovdiv University "Paisii Hilendarski"

    Guys, thanks a lot for your concern! I will check these papers asap. Cheers

  • Sara Östlund Nilsson added an answer:
    Three-spined stickleback as a food
    Is there any place where three-spined stickleback is used as a food (human, domestic pets)?
    Sara Östlund Nilsson · University of Oslo

    Dear Michal, I am very interested in the use of stickleback oil in lamps as well as its use for human consumption.  Would you know anything about stickleback oil used to fuel oil lamps in London? Could you please give me the whole  references so that I can find them ? Many thanks in advance.

  • Peter Kobor added an answer:
    Is there any researcher here open to a corresponding cooperation in work on the breeding and status evaluation of freshwater decapods?

    I would like to start some research in Hungary which is aimed to develop captive breeding technology and evaluate status of the three autochthonous decapods of Hungary and Central-Europe (Astacus astacus, Astacus leptodactylus, Austropotamobius torrentium). For this project I'm looking for a corresponding advisor/consultant/cooperator. Details of the planned work and ideas would be shared via private message/ e-mail.

    Peter Kobor · University of Pannonia, Veszprém

    Thank you, Momir. I will check it with them.

  • Valentin Dupraz added an answer:
    Has anyone ever used the fluorescent dye DCFH-DA (H2DCFDA), to monitor Reactive Oxygen Species (ROS) in marine diatoms ?

    I have a protocol that works fine with chlorophytes, but results are weird with the diatoms. Any ideas ?

    Valentin Dupraz · Institut Français de Recherche pour l'Exploitation de la Mer

    I will look forward to it. Thanks!

  • Michael Sparkman added an answer:
    Is anyone comparing counts of returning adult Chinook salmon (using sonar) with redd counts?

    We use a short range DIDSON in Redwood Cr, and a long range ARIS in the Mad R. Redd surveys are independently counted in Redwood Cr. To date (3 yrs of data), we are not seeing any agreement with sonar counts and redd counts for Chinook salmon and steelhead trout. The redd counts are negatively biased, even if you take into account that not all salmon passing the sonar beam will spawn (pre-spawn mortality). I know there is similar work on the Secesh R in Idaho, and I am wondering if any other place has a similar study going on and what their results might be.

    Michael Sparkman · Anadromous Fisheries Resource Assessment and Monitoring Program

    Thanks Geoffrey, the link did work!

  • Clare Embling added an answer:
    Where should Marine Protected Areas be established to protect The Bottle Nose Dolphin in Cornwall?

    Am devising a campaign for project, any extra info would be greatly appreciated, especially surrounding their dietary requirements/habits and techniques used to assess this. Thank you

    Clare Embling · University of Plymouth

    Hi Hannah,

    I currently have an MRes student who is just starting to look at this for the English Channel region based on ferry and survey data (working with MarineLife). The challenge is having enough data to be able to determine high use areas &/or residency patterns. The Moray Firth and Cardigan Bay (which are current SACs for bottlenose dolphins in the UK) are based on long term photo-ID data which allows for reasonable estimations of population sizes and residency patterns, so areas can be selected that are used repeatedly over time. This is more challenging with sparser data or non-photo-ID data. For porpoises we are trying to determine high use areas that can be put forward as SACs/MPAs (see my paper on my Researchgate profile). The MRes student is likely to use similar techniques, i.e. use habitat models to define high use areas for bottlenose dolphins in the channel and look for areas that are used consistently over time.

    So as yet I can't answer your question as to where they should be placed, but in 9 months time we may have a better answer! And yes, as Chris mentioned, it is also worth talking to the JNCC as they have been looking at where to put SACs for both bottlenose dolphins and harbour porpoises in UK waters.

    I hope that helps a little!


About Aquatic Ecosystems

marine and freshwater aquatic ecology and hydrobiology

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