Coastal blue carbon- help needed

Hello community,

I hope this message finds you well. I am reaching out to seek your assistance with my research project. Specifically, I am struggling to find and adjust data for the Carbon Biophysical Table, particularly regarding biomass yearly accumulation and soil initial/soil yearly accumulation for the species Halophila stipulacea, a type of seagrass.

I have thoroughly reviewed articles for relevant data and also examined sample model data, but unfortunately, the information available is not sufficient for my needs. While I did find the initial biomass data (in tons) for Halophila stipulacea in the model data, I still need data on biomass yearly accumulation and soil parameters.

Here are my specific questions and concerns:

  1. Biomass yearly accumulation and soil initial/soil yearly accumulation data are missing. Do you have any recommendations on where I can find reliable data to fill these gaps, considering there is a shortage of information in my study area? I have already looked into other seagrass data from the same region but have not found what I need.
  2. Does it make sense that the initial biomass of Halophila stipulacea is 0.02 TCO2/ha? I would appreciate any insights or guidance on this matter.

Your help and support would be invaluable to me as I continue with my research. Thank you in advance for any assistance or advice you can provide.

Best regards

Hi @Ymande -

I’ve used this model twice, once on the west coast of the United States (marsh only), once in Caribbean Colombia (including seagrass). In both cases, I had to use some values from studies that were not within my specific study area, and/or values that were not for the specific species in my study area. For Colombia, I first looked for data in the study area, or nearby. Then if I didn’t find published values nearby, I looked for studies within the country but further away (like Pacific Colombia), then looked further away but in a similar climate (one paper from the Caribbean, another included values for the “Tropical Western Atlantic”). In this case, I didn’t have specific species data to work with, and it wasn’t critical for our analysis.

It’s harder if you need to quantify a particular species. If you’re just not finding the species-specific data locally, or further away, then I’d advise looking at studies that are more generally “seagrass” in your area, or similar climate, and either choose one that sounds the most relevant, or perhaps take an average across them, if that seems appropriate.

I don’t really have an opinion about the biomass value for Halophila stipulacea, that value is lower than the ones I found for the Colombia study, but these also varied widely. One thing to make sure is that all of your inputs are in the same units. The model’s User Guide says MgCO2/ha, but they can also be MgC/ha (or g/ha etc), as long as you’re consistent across all of your inputs.

The last thing I’ll say is that I found at least one study noting that seagrasses don’t tend to accumulate biomass over the long term (long-term accumulation is mostly in soil), which may be one reason it’s so hard to find studies providing this value. So you might look into that, because we did assume 0 biomass accumulation for seagrass.

It would be great to hear from anyone else with more experience.

~ Stacie


Hi Stacie
thank you so much for your answer :slight_smile:
do you have the article/study title that noting that seagrasses don’t tend to accumulate biomass over the long term?

Hi Yael -

I went back to my notes, and had specific citations for all of my other values except (of course) that one. But I think that it came from Can Blue Carbon Further Conservation? Approaches to Conservation through a Portfolio of Blue Carbon Options: A Case Study in The Bahamas by Jaclyn Mandoske. Caveat: it is not the most authoritative document, but was done in collaboration with NatCap, and I couldn’t find much more out there at the time regarding biomass accumulation in seagrasses.

One more thing that might be useful is to look through the NatCap-authored and community-authored InVEST studies whose databases can be found on our Publications web page. You should be able to search by model and perhaps find how other people parameterized this (another caveat: I haven’t looked for Blue Carbon studies in there, so don’t know how many there are).

~ Stacie

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Hi Stacie ,
Thank you so much for your time an answer, i will check it :slight_smile:
maybe you can help with another thing, do you know where I can find a guide or explanation how to work, understand and analyze the model’s output in to results?
there is very little information in the model guide and i could not find such explanation in other articles.
thank you for your help!

Hi Yael -

I agree that one thing that’s often missing from our User Guide is guidance about using the results. Perhaps one reason is that each analysis is different, in which results were used, how they were post-processed, and then used for decision-making. The Blue Carbon chapter does have a Use Case section that gives a brief description of how the model was used in a NatCap study in Texas, United States.

If you find any Blue Carbon studies in the InVEST publication databases, they will talk about how they used the model results, so it’s worth looking through any papers you find, even if they’re not in a similar location or climate, just to see their methodology.

~ Stacie