the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 19 Dec 2024
Decoding pelagic ciliate (Protozoa, Ciliophora) community divergences in size spectrum, biodiversity and driving factors spanning global five temperature zones
Abstract. Community structure of microzooplanktonic ciliate in size spectrum, biodiversity and biotic-abiotic interplay are essential components for unraveling their ecological role in marine ecosystems, yet remain challenging to elucidate on a global scale. To address this knowledge gap, we conducted field observational studies across five temperature zones (North Frigid Zone, NFZ; Sub-Arctic Zone, SAZ; North Temperate Zone, NTZ; Torrid Zone, TZ; South Frigid Zone, SFZ). Our analysis revealed that a sharply decline in ciliate abundance and biomass occurred at 100 m layer, with distinct vertical distribution patterns observed in each climate region. Moreover, ciliate size spectra exhibited a decrease trend from small to large size spectra, with steeper slopes observed in the NFZ and SFZ compared to the other temperature zones. Furthermore, an anti-phase relationship between ciliate abundance and tintinnid biodiversity was observed in latitudinal direction, with the TZ and bipolar seas characterized by the highest biodiversity and abundance, respectively. Moreover, a multivariate biota-environment analysis indicated that temperature exert a primary influence on microzooplanktonic ciliates in the global marine ecosystem, and the bottom-up control play a key role in shaping ciliate community. In conclusion, these results underscore the unprecedented divergences in ciliate trait structure among five temperature zones and can be generalised for assessing the potential effects of climate change on pelagic microzooplankton in future marine realm.
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CC1: 'Comment on egusphere-2024-3888', Ping Du, 10 Feb 2025
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The data in this paper are obtained through the accumulation of several scientific cruises, which is very precious and rare. The differences in abundance, biomass, diversity and size spectrum of pelagic ciliate among the five temperature zones were demonstrated through measured data, in addition to the differences between latitudes, the data also showed differences in the vertical patterns of planktonic ciliate abundance, biomass and size structure in the five temperature zones, which is of great value for understanding the global distribution of pelagic ciliate. The analysis on biotic-abiotic interplay is also very meaningful, but the current analysis results in 3.4 are somewhat confused. The main reason is that it is not necessary to show the abiotic factors controlling the spatial variation of ciliates within each temperature zone, because these results are determined by the range of sampling stations in each temperature zone, and are independent of the comparison between the five temperature zones. Thus, the content of part 3.4 and the corresponding discussion needs to be adjusted. I suggest that PCA focus on analyzing the relationship between the dominant species in the five temperature zones and various abiotic factors.
Other specific comments are as follows:
Lines 149-150: "At 200 m depth, temperature and Chl a peaked in the TZ and North Frigid Zone (NFZ), respectively, deviating from salinity patterns, which exhibited high values in both the TZ and NFZ" The expression of this sentence is not clear, modify it to make it clearer.
Lines 142-144: The vertical distribution of chlorophylla in SAZ is not described.
Lines 170-171: "Vertically, the large (> 50μm) and small size-fractions exhibited an inverse distribution characteristic across five temperature zones"The meaning of this sentence is not clear, modify it to make it clearer.
Lines 209-240: The large differences in the relationship between biological and abiotic organisms in different temperature zones may be mainly caused by the difference in the selection of sampling areas, rather than the fundamental differences between temperature zones.
Lines 278-279: “the general trend of steeper slopes at the surface compared to the 200 m layer across all regions suggests a community size shift influencing carbon flux efficiency towards higher trophic levels”It is difficult to understand the relationship between the half sentence before and the half sentence after "suggest", and additional explanation is needed.
Lines 291-292: “the steeper slopes observed in the abundance size spectra in the bipolar seas compared to the tropical, temperate, and sub-Arctic seas might reflect a prevailing trend towards miniaturization”also, it is difficult to understand the relationship between the half sentence before and the half sentence after "might reflect", and additional explanation is needed.Citation: https://doi.org/10.5194/egusphere-2024-3888-CC1 -
RC1: 'Comment on egusphere-2024-3888', Anonymous Referee #1, 15 Feb 2025
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The paper “Decoding Pelagic Ciliate (Protozoa, Ciliophora) Community Divergences in Size Spectrum, Biodiversity, and Driving Factors Spanning Five Global Temperature Zones” (Egusphere-2024-3888) studies pelagic ciliates across five temperature zones. Ciliates play a crucial role in the planktonic food web, and expanding our knowledge—especially through studies like this—is essential for understanding their future in the context of climate change.
The ciliate counting work is impressive. The paper is well-written, and the data analysis is highly appropriate. The discussion is engaging; however, some results should be explored in greater depth. Additionally, the discussion contains overly general ideas from the bibliography.
The main revisions should focus on the figures. In the paper, the figures are too small, and some are difficult to interpret. Some figures in the supplementary materials are more effective than those included in the main text. Please select the most appropriate figures to illustrate the results clearly.
For these reasons, I recommend this paper for publication with minor revisions.
Some mistakes:
- Line 80: field
- Line 73, 87: ciliates
- Line 108: no space after (Utermöhl 1958)
- Line 141: we used
- Figure 5 and figure 6: legend for a, b, and c
- Line 368: indirect
Citation: https://doi.org/10.5194/egusphere-2024-3888-RC1 -
CC2: 'Comment on egusphere-2024-3888', Weiwei Liu, 17 Feb 2025
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Review of egusphere-2024-3888:
The authors presented a detailed and comprehensive dataset of ciliate community distribution across the major temperature zones in the sea, and the ciliate morphospecies were identified in 1,117 samples taken at 175 stations in the Arctic and sub-Arctic Ocean, the North Pacific, the tropical western Pacific, the Indian Ocean, and the Southern Ocean (in global scale). Meanwhile, ciliate abundance and biomass size spectra, as well as species richness and diversity, were related to environmental parameters and depth. Objectives and rationales are clear, robust and well presented. Furthermore, the authors’ analyses confirm general trends (e.g., size-diversity and temperature-diversity relationships for aloricate ciliates and tintinnids, a decrease of ciliate abundance and biomass with depth) and present numerous details for each biogeographic zone worth publishing. However, several shortcomings should be reviewed to more fill the scope of their overall goal. In conclusion, I recommend this manuscript for publication in the Ocean Science characterized with high-ranked international journal after revising some specific comments as follow.
Specific comments:
- Title: pelagic ciliates belonged to Protozoa is well-known in marine plankton realm, thus it’s no need to strengthen it in the title. Just delete this term.
- line 48: Common sense error. The “anthropogenic CO2 emissions” should be revised into “anthropogenic CO2 emissions”.
- line 93: please make sure that whether the cruise conducted in the Indian Ocean in March 2021 aboard the R.V. “Xiangyanghong 10”? I remembered that this cruise might be conducted by the R.V. “Xiangyanghong 6” in previous manuscript I have reviewed.
- The Methods section lacks detail. I recognized that the method how you calculated the size-fraction of aloricate ciliate, while how the biomass spectra were constructed (size categories?) is unclear. Please state clearly relate to the calculation of the biomass spectra.
- line 122: Convert pg C to μg C.
- line 153: What do you mean the “sandwich structure” for temperature. I cannot find this phenomenon clearly in Figures S1 and S3. Therefore replace it.
- Figure 2: you have mentioned the abbreviation of the five temperature zones in figure 1: the North Frigid Zone (NFZ), sub-Arctic Zone (SAZ), North Temperate Zone (NTZ), Torrid Zone (TZ) and South Frigid Zone (SFZ), thus there is no need to write this part again.
- line 275: I wondered that it not clear what is meant by “monospecific trophic levels, such as microzooplanktonic ciliates”; ciliates represent more than one trophic level (i.e., as phototrophs, bacterivores, herbivores/omnivores, predators, parasites). Please state it clearly in this part.
- In the discussion part, the author mentioned that the bottom-up control is the resource limitation as previous pointed. In this study, temperature is environmental factor (=environmental filter) for which exert a primary influence..... I strongly suggest to clearly separate in Discussion the interpretation of environmental filters and trophic mechanisms as explanatory variables for the patterns revealed and to make corresponding corrections in the Abstract.
- In section 4.3, a recent meta-analysis contradicts the authors’ conclusion because ciliate mortality appears to be unaffected by temperature (Weisse, 2024, Limnol. Oceanogr.), which was inconsistent with your results. How do you cope with this phenomenon? By the way, T determines organism mortality contradicts empirical evidence for ciliates (Weisse 2024)
- line 316: the author mentioned that the positive correlation between tintinnid species richness and temperature, while this correlation may be an indirect effect.
- line 349: CO2
- line 360: add the total number of samples.
- At last, I’m curious about a phenomenon that the author spend a lot of description in discussing the relationship between the environmental variables and “bottom-up control”, and previous studies recognized that the plankton community was strict restricted by outer environmental resources, which was known as “bottom-up control”. However, how do you identify the correlation between the environmental variables and “bottom-up control”?
Citation: https://doi.org/10.5194/egusphere-2024-3888-CC2
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