This manuscript presents the results of the study of spatio-temporal variations of Chl-a blooms in the Bransfield Strait at a climatological scale (1998–2018). An original technique, based on the results of remote sensing and hydro-meteorological data obtained in situ, is proposed for a suitable monitoring of these blooms.

The material is well structured and clearly presented.

In my opinion, the manuscript should be accepted to publication, taking into account the minor concers, stated below:

Figure 1: The indices (a) and (b), marked in the figure’s caption are absent in the images.

Line 129 -130: These sentences should be deleted.

Figures 2, 3 ,4: It’s practically impossible to distinguish the colours of the stations in the map on the subfigure on right below that does not allow identification of the corresponding T,S curves on the subfigure above.

Line 542-543 should be combined.

The study presented in the abstract provides valuable insights into the spatio-temporal variations of chl-a blooms in the Bransfield Strait over a climatological scale. The researchers tackle an important problem of monitoring these blooms using remotely-sensed observations and propose a novel approach by dividing the Bransfield Strait based on the Peninsula Front. This approach is supported by the characterization of various climatological fields and guided by both novel and historical in situ observations. One of the strengths of this study is the identification of two distinct phytoplankton assemblage niches: the Transitional Bellingshausen Water (TBW) and Transitional Weddell Water (TWW) pools. By analyzing the characteristics of these pools, such as water temperature, salinity, and mixing, the study provides a comprehensive understanding of the environmental factors influencing chl-a blooms in the Bransfield Strait. The monthly climatological description of the two blooms occurring on both sides of the Peninsula Front enhances our understanding of the interplay between chl-a blooms in the TBW and TWW pools.

The integration of SST and chl-a data for monitoring chl-a blooms is another essential aspect of this study. By combining these datasets, researchers can track the year-to-year variations of chl-a blooms in the Bransfield Strait and gain insights into the long-term dynamics of phytoplankton assemblages. Similar approach has been applied in some of the coastal ocean that is useful to reveal the dependence of chl-a to dynamical factors. However, the authors failed to calculate the wind in correct approach that can lead to significant error in estimation.

In conclusion, the study offers valuable contributions to the understanding of spatio-temporal variations of chl-a blooms in the Bransfield Strait. The proposed approach of dividing the strait based on the Peninsula Front, the identification of distinct phytoplankton assemblage niches, and the integration of SST and chl-a data for monitoring are all commendable. This research has the potential to enhance our knowledge of chl-a blooms in the region and contribute to the field of marine ecology and remote sensing. However, there are some unclear descriptions, even errors, as well as careless in writing; thus, a major revision is necessary to improve the quality.

Major comments:

1. A major error is the calculation for wind stress shown in equation (1). The zonal and meridional wind stress should be calculated respectively for both wind speed and wind vector. However, the authors applied the wind speed as the total wind speed. This is definitely resulting in significant over estimation of wind stress.

1. The major feature in Figure 1(b) is less helpful and can be combined into Figure 1(a). While the mean SST or chl-a (contour) can be shown instead for readers to understand the major patterns in the study region.

1. The front is generally identified using the SST gradient and the frontal probability is usually applied for identifying the location of fronts. The identified frontal distribution from satellite observation can be compared with the cruise observation. The authors should elaborate more discussion related with front dynamics in current study.

1. The same approach is actually applied by Yu et al. (2019, JMS) for underscoring the dependence between chl-a and other factors. Thus, the creativity is not relying on the intercorrelation among different parameters, unless the difference between current and former study is highlighted.

1. Many careless in the writing, such as forgetting to upper case the unit of chlorophyll, the reference (Sangrà et al. (2017)), chl-a and SST among others should be used after defining the abbreviation. The authors should double check the text throughout the manuscript.

1. The governing dynamics should be discussed with observational evident, though only two cruises were available. Additional satellite observations or literature result can be applied as supplementary proof for the underlying dynamics.