This is a very good study aiming to develop benthic foraminifera as a proxy of drought using Ba/Ca ratios within the foraminiferal test. Living foraminifera have been sampled from two sites from a fjord at the Swedish west coast during three different seasons (Sept 2018, Feb 2019, June 2019) while a severe drought with reduced runoff occurred in 2018. Two species have been used for trace element analysis (Bulimina marginata and Nonionellina labradorica). The manuscript is well structured and written. Figures and tables are of high quality, and supplementary material is made available. I only have some few specific comments.

Line 1: The resulting Ba/Ca ratios reflect both river discharge and drought. Perhaps the title should be altered to “River discharge and drought recorded in...”

Line 52: The review by Howe et al. (2010) is not specifically on benthic foraminifera. It would be beneficial to have one to two additional references here specifically on foraminifera, e.g. Murray (2006), ISBN 0521828392.

Lines 244-246: Ba/Ca ratios represent river discharge 30 or 60 - 90 days ago. Are there other factors causing this than foraminiferal growth and lag in the transport of Ba/Ca? What about hydrological fluctuations of the river or other environmental factors?

Lines 260-261: “... with generally lower Ba/Ca in the outer-fjord site during 2018 (Fig. 3)”. The values are relatively similar between sites for N. labradorica? Please make describe this in the text instead of using “generally”.

Line 382-405: In the section on implications, it would be beneficial to evaluate the possible effects of the lag of 30 or 60-90 days between the river discharge and the Ba/Ca ratios when establishing paleorecords of river discharge and possibly drought.

This paper addresses the potential of using Ba/Ca on benthic foraminifera as a proxy for hydrological changes based on a case study from the Gullmar Fjord, Sweden. The results of the study indicate a potential for using especially Ba/Ca of B. marginata as an hydrological proxy, despite some caveats regarding  specific conditions prevailing at the study sites and other factors that might influence the foraminiferal ratio. The paper is very well written und the figures are of high quality. The motivation of the study, experimental design and the results are very concisely presented and the data is thoroughly discussed including its limitations. In summary, I really enjoyed reading the manuscript and support its publication in Biogeosciences.

However, there is one important aspect that appears to be missing: According to the Material & Methods section, water samples have been obtained during the sampling campaigns, but no trace element analyses on the water samples are reported. This might be an important information, as the pore water profiles show no distinction between the different sampling periods, despite the presumed strong hydrological difference between the dry year 2018 and the wet year 2019. Hence, the different Ba/Ca signature of B. marginata between both years does likely not derive from differences in the pore water composition. Albeit bottom water Ba/Ca would also provide only snapshots, it might provide important information about the Ba-transfer into the pore water and the general amplitude of bottom-water Ba/Ca fluctuations in the Fjord. The authors use the hydrological observational data to indirectly infer Ba/Ca in the Fjord’s water column but direct measurement of water composition might well be helpful. Hence, I would like the authors to comment if such measurements exists or add them if possible as water analyses are analytically relatively straight forward.

Further specific comments:

- The supplementary information should be separated for figures and tables. Supplementary Figure 4 has no caption.

- Fig. 2a: please indicate the location of the study area.