Process Controls of the Live Root Zone and Carbon Sequestration Capacity of the Sundarbans Mangrove Forest, Bangladesh (Version 1, Original)
|Reviewer 1 Swapan Kumar Sarker Associate Professor, Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh||Reviewer 2 Nobuo Imai Tokyo University of Agriculture|
Approved with revisions
Bomer, E.J.; Wilson, C.A.; Elsey-Quirk, T. Process Controls of the Live Root Zone and Carbon Sequestration Capacity of the Sundarbans Mangrove Forest, Bangladesh. Sci 2020, 2, 35.
Bomer EJ, Wilson CA, Elsey-Quirk T. Process Controls of the Live Root Zone and Carbon Sequestration Capacity of the Sundarbans Mangrove Forest, Bangladesh. Sci. 2020; 2(2):35.Chicago/Turabian Style
Bomer, Edwin J.; Wilson, Carol A.; Elsey-Quirk, Tracy. 2020. "Process Controls of the Live Root Zone and Carbon Sequestration Capacity of the Sundarbans Mangrove Forest, Bangladesh." Sci 2, no. 2: 35.
Article Access Statistics
Associate Professor, Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh
I think this is an important study with important results. It produces new knowledge on the geo-morphology of the Sundarbans. I appreciate the authors for their efforts. However, I suggest they may think about extending their sampling afforts in their future works. The sampling sites were located in a small area in the northeastern area which is mostly inundated only during the spring tides and mostly supports less salt-toleant mangrove plants. The sedimentation rate and hydrology in the eastern, western and near-sea southern zones are quite different. So looking at these areas in their future studies would help us to have a more robust and general idea on the Sundarbans' hydro-geomorpholy.
Response to Reviewer 1Sent on 10 Jul 2020 by Edwin Bomer, Carol Wilson, Tracy Quirk
Tokyo University of Agriculture
This study investigated the surface elevational change of live root zone by using SSET, and the relationship between the surface elevational change and soil characters (e.g., ORP, water content, soil particle size, bulk density) in Sundarbans mangroves. This study can provide useful information, and the scope of this study is well within the scope of Sci. However, because several problems could be found (see below), I would suggest that major revision is required before the paper can be accepted.
I do not fully understand the stability of SSET (shallow surface elevation table), and therefore, the data accuracy of surface elevation change. RSET (rod surface elevation table) usually installed into the soil until the basic rock for stability. A benchmark depth ranges from several to nearly 20 m, as the author’s previous paper (Bomer et al. 2020 Catena). But, benchmark depth of SSET was only 0.75 m in this study. Is the stability of SSET broadly accepted? If so, OK, but if not, explanation and evidence for stability of SSET (with the references of previous studies showing the stability of SSET) is needed.
While this study focuses on elevational change in live root zone (top 0.75 m soils), the author’s previous paper (Bomer et al. 2020) focuses on top 15-20 m soils. The stations of SSET-1, -2, and -6 in this study may correspond to RSET-S1, -I1, and -S2 in the previous paper. If the stations of RSET and SSET are located closely to each other, …
・If one station has two station names, it would be better to continuously use only one name to avoid future confusion.
・Additional analysis how the water level data derived from measurement using piezometer on elevational change in live root zone can be conducted. I consider that such data can enrich the paper.
For section 5.1, the paragraph structure should be changed. I consider that one of the most important result of this study is that LRZ showed positive elevational change (mean±SD = 2.42±0.26 cm/yr), and 80% of sediment accretion results from change in LRZ. But, these results were shown in the “end” of section 5.1, while a detailed (bit lengthy) discussion of the mechanism of shrink-swell dynamics based on soil characters (porewater content, soil particle size, ORP and bulk density) was emphasized in section 5.1. Comparison of shallow surface elevational change and total sediment accretion needs to be emphasized, and be stated in the Methods, Result, and early part of 5.1 Discussion section.
Discussion section is bit lengthy. This is because 1) topics with no data often emerged (e.g., leaf-consuming organisms), and 2) several data and results are firstly shown in Discussion section, but not in Result section. For example, comparison of soil C sequestration between the SMF and mangroves worldwide (Fig. 10) is firstly shown in Discussion. However, considering that the “objective of the study is to evaluate the below-ground carbon sequestration capacity of the SMF and compare our findings with other mangrove forests across the globe”, such results can be shown in Result section.
In abstract, there is no detailed data on elevational change. At least mean±SD value (2.42±0.26 cm/yr) is needed
How many rods or pipes per one SSET?
P12L9-10, “leaves should fully decompose after approximately one year.”
Middleton and McKee (2001) studied the early decomposition process of leaves, twigs and roots. Considering the particulate organic matter, leaves may not fully “decompose” after 1yr. Middleton and McKee (2001) used the terms “decay” or “degradation”.
I do not fully understand the data accuracy of soil pore-water content. The authors collected 1-m deep core using a 6-cm diameter half-cylinder auger, and 2-cm thick subsamples were taken from cores every 10 cm. Such sampling procedure may often underestimate the pore-water content, because soil pore-water may often largely leak from the soils within the half-cylinder auger. If so, it would be better to note this phenomenon on methods section, and again, better to consider the use of water-level data derived from measurement using piezometer.