Water Depth Research Articles

Experimental assessment of the effect of black dye and water depth on the performance of PV/solar distiller

The current article investigated the possibility of enhancing the solar distiller performance joined with the photovoltaic/thermal solar collector by increasing the absorption of solar radiation through the use of black dye. Two identical systems were built, the first system is a conventional double-slope solar distiller, while the other is a modified version that combines a PV/thermal solar collector with a double-slope solar distiller. The effect of the black dye and the water depth in the basin on the solar distiller’s performance has been studied. The results showed that the modified system works well in cold winter conditions in comparison with hot summer conditions. The results also showed that the water depth inside the distiller basin effectively affects the output of the system. The system achieved better performance when the water depth was 3 cm in the still basin than when the water depth was 5 cm. The total production and efficiency of the improved distiller at the water height of 3 cm at the basin with adding the black dye in February were 1.378%, and 22.02% respectively. while for the conventional model, the total productivity and efficiency were 0.348 liter/day and 5.31% respectively for the same conditions.

Modulation effect of uniform flow on three-dimensional freak wave generation in arbitrary water depth

In arbitrary water depths, the influence of uniform flow, which includes transverse and longitudinal flows, on the generation of three-dimensional (3D) freak waves is examined. A modified Davey–Stewartson equation is derived using potential flow theory and the multiscale method. This equation describes the evolution of 3D freak wave amplitude under the influence of uniform flow. The relationship between two-dimensional (2D) modulational instability (MI) and the generation of 3D freak waves, as represented by the modified 3D Peregrine Breather solution, is explored. The characteristics of 2D MI depend on the orientation of the longitudinal and transverse perturbations. In shallow waters, the generation of freak waves by MI is challenging due to the minimal orientation difference, and longitudinal flows hardly affect the occurrence of MI. Variations in relative water depth can contribute to forming shallow-water freak waves. In finite-depth waters, oblique modulation leads to MI, whereas in deep and infinite-depth waters, longitudinal modulation gains significance. In environments of finite-depth, deep, and infinite-depth waters, the divergence (convergence) effect of longitudinal favorable (adverse) currents reduces (increases) the MI growth rate and suppresses (facilitates) freak wave generation.

Fishes move to transient local refuges, not persistent landscape refuges during river drying experiment

Abstract Anthropogenically driven flow intermittency is increasing in freshwater streams, with important implications for the management and conservation of aquatic ecosystems. Because most freshwater fishes are mobile, they are expected to emigrate from intermittent reaches, but this may not be true in streams transitioning from perennial to intermittent. Here, we attempt to determine if riverine fishes vacate drying reaches before intermittency or remain in local refuges. We implemented a controlled, in situ experimental flow reduction resulting in intermittency, reducing flows from ~1.0 to 0 m3/s over a 3‐week period. We monitored fish and fish‐habitat changes over a 5‐week period before, during and after flow reductions. During flow reductions, total wetted habitat was ultimately reduced by 91%. Habitat loss over time was not equal among habitat types: pool habitat increased slightly as run habit was lost, and backwater and isolated pool habitats were not strongly related to discharge. Likewise, water depth in run habitats decreased faster than other habitats. Only the river carpsucker Carpiodes carpio appeared to move upstream during flow recession; seven other species remained within drying sites. Habitat loss negatively affected fish populations, but at a lower rate than that at which habitat was lost, until sites dried completely. Overall, two species, red shiner Cyprinella lutrensis and western mosquitofish Gambusia affinis, had increased population growth during the study, whereas the remaining species had population declines. Fishes were able to find transient local refuges during flow reductions but did not vacate sites before intermittent conditions. Accounting for lack of emigration from anthropogenic flow‐intermittent reaches will be important for designing conservation actions for fishes threatened by increasing flow intermittency. Creation of refuge habitats may not be effective for widely dispersed species that do not actively seek refuge habitats, unless those habitats support enough individuals to maintain resilience following the intermittent conditions.

Variation in water utilization by mammal diversity in Khao Phaeng Ma Non-hunting area, Thailand

Access to suitable water sources is important for mammals. This study aimed to compared mammal diversity and water use among water springs, standard artificial ponds, and water pans within the Khao Phaeng Ma Non-Hunting Area in 2020 and 2021. Two camera traps were installed at each water sources for 749 nights with a total of 12 camera traps of 6 water sources. A total of 19,467 photographs were recorded comprising 13,777 photographs of gaur (Bos gaurus, vulnerable and the most important species in the area), and 5690 photographs of other mammals. In the wet season, relative use was highest at standard artificial pond number 2, which is established in the forest plantation area (4 × 4 m spacing, 12–20 m height, and 60%–80 % crown cover) and has a high volume of water, and at water pan number 1, which mimics a natural water spring in the man-made grassland and can supply water to mammals throughout the year. In the dry seasons, relative use was highest at water pan numbers 1 and 2; at the same time, other water sources dried up. During the study period, the number of mammal species was highest at water pan number 1 (10 species, diversity index [H′] = 1.38), and water pan number 2 (11 species, H′ = 1.75). Grazers and browsers, including gaur, sambar deer (Rusa unicolor), northern red muntjac (Muntiacus vaginalis), omnivores (e.g. wild boar, Sus scrofa), and Asian black bear (Ursus thibetanus), used the water pan in the artificial grassland and standard artificial pond in the forest plantation rather than the water spring in the dry evergreen forest. Beside forest types, the use of water springs was associated with water period (months), while the use of standard artificial pond and water pans was associated with water surface area, water depth, altitude, species diversity, and species richness, and number of mammals photographed. The results show that water pans were more suitable for utilization by mammals than are other water sources.

Crustose red algae in deep time environments: Palaeoecological insights from northeastern India and Türkiye (Turkey)

Crustose red calcareous algae are key organisms in benthic ecosystems worldwide with critical functions like reef-building and substrate stabilization. Coralline algae thrived as major carbonate producers, with corals and/or larger benthic foraminifera (LBF) in numerous shallow-marine Tethyan carbonate platforms from the early Palaeogene to the Neogene. The Palaeocene–Eocene limestone successions in the Jaintia and Khasi Hills, Meghalaya, northeastern India, encompass two principal community types — algal-foraminiferal and coralline algal, with no associated colonial corals, while the Oligocene–Miocene carbonates from the Sivas basin and Siirt province in Türkiye are characterized by an algal-foraminifera assemblage with bryozoans, corals, and molluscs as other noteworthy components pertinent to the carbonate platform environment. We found that the diversity and ecology of these algal communities were influenced by systematic structure of the algal assemblage, sediment input, substrate stability, water depth, and hydrodynamic energy. The algal assemblages from different epochs and varying localities diverge based on the sedimentary regime, environmental settings, and the predominant taxa. The climatic transition from the Palaeocene–Eocene greenhouse to the Oligocene–Miocene icehouse corresponded to a shift from crustose algal assemblages dominated by Sporolithales to assemblages dominated by Hapalidiales.

Effect of coating of waste toner powder weight concentration on absorber plate of solar still

A solar still is a device that uses sun energy to convert brackish or salted water into drinkable water and its distillate output is lower. In addition, it is the primary issue with the solar still; thus, researchers are looking for fresh ideas to raise the distillate output. The primary goal of this study is to examine the effects of mixing different weight concentrations (5%, 10%, 15%, and 20%) of toner waste powder (TWP) nanoparticles with black paint on distillate output and energy–exergy efficiency analysis. Two solar stills of similar dimensions have been used in the current study from February to March 2023 at Palanpur, Gujarat, India. Basin water, inner glass surface temperature, distillate output, and intensity of solar radiation are all monitored hourly for solar stills. This research indicates that the application of TWP coating to absorber plates increased the distillate output, and the highest distillate output of 955 ml was achieved at 10 wt. % concentration of nanoparticles, which is 40.03% higher than a conventional solar still (CSS) and 33.38%, 10.40%, and 30.64% higher than 5, 15, and 20 wt. % concentrations of nanoparticles at the same water depth, respectively. In addition, it was discovered that adding TWP to the solar still enhanced energy and exergy efficiency. Based on this research, it can be concluded that TWP is a suitable, inexpensive resource to boost energy and exergy efficiency and distillate output of solar still.

Monitoring of water Quality to assess Seasonal Color Changes of Lunar-Lubha River in East Jaintia Hills, Meghalaya (India)

The Lunar-Lubha River is a significant river in Meghalaya, India, flowing through the Jaintia Hills and eventually reaching Bangladesh’s Surma valley. During winter, the river undergoes a remarkable transformation, changing its color from turquoise to a vibrant sky-blue hue. This study investigated the reason behind this color change by examining the physicochemical characteristics of the river water during pre-monsoon, post monsoon and winter season of the year 2020 to 2022. Chemical properties of the white-powdery sediment (which acts as light reflecting media) found on the riverbed of the color-changing stretches of the river were also investigated. The analysis revealed the presence of high levels of Iron (Fe) and Alumina (Al) in sediments of the Lunar-Lubha River beds. The water quality in stations located at Lunar River can be designated below-E as per Central Pollution Control Board (Govt. of India) guidelines as the water in those stations is not fit for drinking, bathing, propagation of marine life as well as irrigation or agricultural uses. The blue coloration is more prominent in the deeper sections of the river compared to the shallow stretches. This observation aligns with the argument that shorter wavelengths of light scatter more as the depth increases. The presence of light scattering effect due to variation in water depth and the white-colored sediments at the riverbed could explain the intensified blue color in the river. The apparent blue color of the Lukha River is most likely an illusion induced by the scattering effect rather than the genuine blue color of the water.

Life Cycle Characteristics and Distribution of Giant Grenadier Coryphaenoides pectoralis (Macrouridae) in Northwest Bering Sea

The outcomes from the survey research in distribution of the giant grenadier Coryphaenoides pectoralis at different stages of development in the Northwest Bering Sea over 1963–2020 have been reported. The data for 37 thousand catches performed with the bottom and multi-depth trawls at the depths between 0–1200 m are processed. It has been revealed that the species fish tend to spawn throughout the year, with two periods of peak spawning activity in the second half of a spring season and from the late summer season to the first half of an autumn season. The female fish ready to spawn migrate down the water column, keeping deeper than 600 m, where the males ready to spawn are concentrated. After spawning, they come back to the feeding areas of less water depths. The juvenile giant grenadier less than 30 cm in length can be encountered in the mesopaelagic and upper bathypelagic zones, which do not appear to form dense aggregations. The majority of the specimens less than 30–40 cm in length and smaller commonly leave this water column layer to occupy the bottom water layers along the continental shelf. Such differentiation between the juvenils and the sexually mature specimens can provide the opportunity to avoid cannibalism and to use the habitat food sources efficiently.

Comparative exergy and economic analyses of single slope solar desalination unit combined with concentrator integrated evacuated collectors

This paper deals with the exergy analysis of single slope solar desalination unit combined with N number of compound parabolic concentrator integrated evacuated tubular collectors (NCPCETC-SU) considering New Delhi climate. An exhaustive computation considering each month of year is carried out. The methodology consists of feeding all fundamental equations with relevant data to MATLAB code and presenting the output in the suitable form. Results of NCPCETC-SU are compared with results of SU incorporated with evacuated tubular collectors (NETC-SU). Concludingly, the annual exergy and daily exergy efficiency for NCPCETC-SU are higher by 36.51% and 30.81% than NETC-SU for same mass flow rate, N and water depth under similar climatic situation. The annual freshwater output is higher by 16.81% and freshwater cost is higher by 9.85% at 2% rate of interest for NCPCETC-SU than NETC-SU respectively. Further, the freshwater cost of NCPCETC-SU can be diminished by increasing the concentration ratio.

The Upwelling Source Depth Distribution and Its Response to Wind Stress and Stratification

Abstract Coastal upwelling, driven by alongshore winds and characterized by cold sea surface temperatures and high upper-ocean nutrient content, is an important physical process sustaining some of the oceans’ most productive ecosystems. To fully understand the ocean properties in eastern boundary upwelling systems, it is important to consider the depth of the source waters being upwelled, as it affects both the SST and the transport of nutrients toward the surface. Here, we construct an upwelling source depth distribution for parcels at the surface in the upwelling zone. We do so using passive tracers forced at the domain boundary for every model depth level to quantify their contributions to the upwelled waters. We test the dependence of this distribution on the strength of the wind stress and stratification using high-resolution regional ocean simulations of an idealized coastal upwelling system. We also present an efficient method for estimating the mean upwelling source depth. Furthermore, we show that the standard deviation of the upwelling source depth distribution increases with increasing wind stress and decreases with increasing stratification. These results can be applied to better understand and predict how coastal upwelling sites and their surface properties have and will change in past and future climates.

Leveraging catchment scale automated novel data collection infrastructure to advance urban hydrologic-hydraulic modeling

Lack of long-term hydrological observations in urban catchments presents a significant obstacle to advancing reliability and accuracy of urban flood models, as sensor-based depth, flow or velocity monitoring in stormwater drainage networks is costly and rarely available. Commonly available networked technologies e.g., traffic cameras and cell phones, collectively referred to as novel data sources, if properly leveraged, could provide a high-quality, cost-effective source of urban hydrological observations. This proof-of-concept study utilizing experimental data collection infrastructure in Flagstaff, Arizona used remotely sensed flood-cameras based water depth time series and single point data, and citizens’ contributed single point data for model parameterization. An approach to reduce the number of parameters while addressing spatial heterogeneity was applied before parameterization. The results demonstrate the reduced uncertainty and improved prediction accuracy from calibrated model even from a single event calibration, emphasizing the potential of novel data in advancing pluvial flood modeling in challenging urban contexts.

An analytical study for predicting incipient motion velocity of sediments in ecological open channel flows

Sediment movements on the riverbeds are crucial in fluvial processes. Therefore, studying incipient sediment motion is valuable for predicting changes in sediment behavior. In this study, the influence of aquatic vegetation is introduced into the momentum balance equation under the condition of a bare bed. The presented model for incipient sediment motion in open channels covered by vegetation is derived, in consideration of vegetation density and relative submergence. This study simplifies the model format. The model and its coefficients demonstrate good applicability to various working conditions without requiring numerous changes. The predicted velocity determined by the proposed model is validated against experimental data. Results show excellent agreement between the two in various scenarios, including combinations of rigid or flexible conditions and submerged or emergent states. Additionally, the velocity for incipient sediment motion is observed to decrease with increasing vegetation density. However, a further increase in vegetation density may amplify vegetation resistance, hindering incipient sediment motion. Meanwhile, sediment movement becomes challenging as water depth increases, assuming that flow discharge and vegetation conditions remain constant.

The effect of planting grass filter strips on fishes in agricultural headwater streams

Abstract Grass filter strips (i.e., herbaceous riparian buffers) are a widely used conservation practice in the United States to mitigate the impacts of agriculture on streams and rivers. Yet, only a limited amount of information is available on the effects of grass filter strips on stream fishes and instream habitat conditions and long‐term assessments are rare. The objective of this research was to document the long‐term effects of planting grass filter strips adjacent to channelized agricultural headwater streams on fish community structure and instream habitat. Fishes, instream habitat and riparian characteristics were sampled from three channelized agricultural headwater streams without grass filter strips, three channelized agricultural headwater streams with grass filter strips and two unchannelized streams having forested riparian habitats in central Ohio from spring of 2006 to autumn of 2015. Fish species richness, abundance, darter species richness, per cent darters, sunfish species richness, minnow species richness and per cent headwater fishes did not differ among riparian habitat types. Darter species richness and per cent darters differed annually. Mean water depth, velocity, wetted width, instream habitat diversity, dominant grain size and per cent instream wood did not differ among riparian habitat types. Mean water depth, water velocity, wetted width and instream habitat diversity exhibited annual differences. Additionally, mean riparian width, woody vegetation density and per cent canopy cover were greater in forested streams than the unplanted and grass filter strip streams. Riparian characteristics did not differ annually. The lack of fish community responses 10–13 years after planting grass filter strips is probably due to the lack of corresponding changes in hydrological characteristics, substrate and instream wood amounts. These results suggest that grass filter strips should not be implemented alone but in conjunction with conservation practices that will improve physical habitat quality and water quality.

Morphology and Sediment Dynamics of Blossom Shoals at Icy Cape, Alaska

AbstractCapes and cape‐associated shoals represent sites of convergent sediment transport, and can provide points of relative coastal stability, navigation hazards, and offshore sand resources. Shoal evolution is commonly impacted by the regional wave climate. In the Arctic, changing sea‐ice conditions are leading to (a) longer open‐water seasons when waves can contribute to sediment transport, and (b) an intensified wave climate (related to duration of open water and expanding fetch). At Blossom Shoals offshore of Icy Cape in the Chukchi Sea, these changes have led to a five‐fold increase in the amount of time that sand is mobile at a 31‐m water depth site between the period 1953–1989 and the period 1990–2022. Wave conditions conducive to sand transport are still limited to less than 2% of the year, however—and thus it is not surprising that the overall morphology of the shoals has changed little in 70 years, despite evidence of active sand transport in the form of 1‐m‐scale sand waves on the flanks of the shoals which heal ice keel scours formed during the winter. Suspended‐sediment transport is relatively weak due to limited sources of mud nearby, but can be observed in a net northeastward direction during the winter (driven by the Alaska Coastal Current under the ice) and in a southwestward direction during open‐water wind events. Longer open‐water seasons mean that annual net northeastward transport of fine sediment may weaken, with implications for the residence time of fine‐grained sediments and particle‐associated nutrients in the Chukchi Sea.

The resistance of Georgia coastal marshes to hurricanes

AbstractEcosystems vary broadly in their responses to disturbance, ranging from highly impacted to resilient or resistant. We conducted a large‐scale analysis of hurricane disturbance effects on coastal marshes by examining 20 years of data from 10 sites covering 100,000 ha at the Georgia Coastal Ecosystems Long‐Term Ecological Research site distributed across gradients of salinity and proximity to the ocean. We analyzed the impacts of Hurricanes Matthew (in 2016) and Irma (in 2017) on marsh biota (plants, crabs, and snails) and physical attributes (erosion, wrack deposition, and sedimentation). We compared these variables prior to the storms (2000–2015) to years with storms (2016, 2017) to those after the storms (2018–2020). Hurricanes generated storm surges that increased water depth and salinity of oligotrophic areas for up to 48 h. Biological variables in the marsh showed few effects of the hurricanes. The only physical variable affected was creek bank slumping; however, slumping had already increased a year before the hurricanes, suggesting that slumping could have a different cause. Thus, our study uncovered only minor, ephemeral impacts on Georgia coastal marshes, highlighting their resistance to hurricane disturbance of the lower magnitude that typically confronts this region of coastline.

Rehydration of degraded wetlands: Understanding drivers of vegetation community trajectories

AbstractDegradation of wetland ecosystems results from loss of hydrologic connectivity, nutrient enrichment, and altered fire regimes, among other factors. It is uncertain how drivers of wetland ecosystem processes and wetland vegetation communities interact in reversing the ecological trajectory from degraded to restored conditions. We analyzed biogeochemical and vegetation data collected in wetlands of the Florida Everglades at the start of (2015) and during (2018 and 2021) the initial stages of rehydration. Our objectives were to analyze the allocation of carbon and nutrients among ecosystem compartments and correlated trajectories of vegetation community change following rehydration, to identify the drivers of change, including fire, and analyze macrophyte species‐specific responses to drivers. We expected to see changes in vegetation toward more hydric communities that would differ based on wetland baseline conditions and the magnitude of the hydrologic change. During the study period, both length of inundation and surface water depth increased throughout wetlands in the region, and four fires occurred, which affected 51% of the sampling locations. We observed biogeochemical shifts in the wetland landscape, driven by both hydrology and fire. Total phosphorus concentrations in soil and flocculent detrital material decreased, while soil carbon:phosphorus and nitrogen:phosphorus mass ratios increased at sites further away from water management infrastructure. Transitions in vegetation communities were driven by an increase in hydroperiods and by the distinct changes in nutrient concentrations or soil stoichiometric ratios in each subregion. The abundance of macrophyte species typical of short‐hydroperiod prairies strongly decreased, while dominant long‐hydroperiod species, such as Eleocharis cellulosa, expanded. Fire facilitated the expansion of thickly vegetated plumes of invasive Typha at sites close to the water inflow sources. Overall, restored hydrology shifted vegetation community composition toward higher abundance of long‐hydroperiod species within six years. In contrast, removal of invasive vegetation controlled by soil phosphorus concentrations will likely require long‐term and interactive restoration strategies.

System Parameters Sensitivity Analysis of Ocean Thermal Energy Conversion

Ocean Thermal Energy Conversion (OTEC) is a technology to harvest the solar energy stored in the ocean by utilizing the temperature difference between warm surface and cold deep seawater. Considering that the OTEC system works in a low-temperature range, the present paper assessed the technical resources comprehensively by acquiring in-situ thermocline data and conducting a sensitivity analysis of the system parameters. The in-situ temperature profile data were measured in the waters of North Bali, Indonesia. The temperature gradient data based on field measurements were then compared with the HYCOM consortium model. The data were then used as input in the OTEC power and efficiency estimation through a single-stage ranking cycle. The analysis was conducted by varying the type of working fluid, the performance of the heat exchanger, and the location to investigate how the system parameters influenced the power produced. Using an unusual combination of parameters made it difficult to analyze the resulting data multiple times. However, with reference-based analysis and the formulation of calculations, the sensitivity of each parameter could be assessed at both locations. As a result, the ammonia working fluid provided the highest net power output of the system but had the lowest efficiency of all working fluids. The heat exchanger performance in terms of net power and efficiency cannot be separated from the seawater mass flow requirement. This referred to the results where the heat exchanger with a temperature difference of 3°C before and after the seawater passed through the heat exchanger and produced the highest net power and efficiency. Additionally, the net power output reached its convergence level at a water depth of 400m for the Bungkulan site and 450m for Celukan Bawang, which was proportional to the thermocline tendency. Doi: 10.28991/ESJ-2024-08-02-04 Full Text: PDF

Enhancing drinkable water production in conical solar distillers: Comparative analysis of magnet fin heights

This paper presents a comparative experimental analysis aimed at improving the production of drinking water from conical solar distillers using magnet fins as a low-cost and efficient storage material. Cylindrical magnet fins with a diameter of 1.6 cm were strategically placed at various heights (2 cm, 1.5 cm, 1 cm, and 0.5 cm) with a spacing of 5 cm on the absorber plate to increase the absorption area and heat transfer to the basin water. Three modules were tested under identical conditions over a two-day period with a fixed water depth of 2 cm (corresponding to the maximum magnet fin height). On the first day, the Traditional Conical Solar Distiller (TCSD), the Conical Solar Distiller with Magnet Fins at a height of 2 cm (CSD-MF-2), and the Conical Solar Distiller with Magnet Fins at a height of 1.5 cm (CSD-MF-1.5) were evaluated. On the second day, the TCSD, the Conical Solar Distiller with Magnet Fins at a height of 1 cm (CSD-MF-1), and the Conical Solar Distiller with Magnet Fins at a height of 0.5 cm (CSD-MF-0.5) were tested. The results showed that the daily water yield from the TCSD at a water depth of 2 cm was 5.50 L, whereas the conical solar distillers with magnet fins at heights of 2 cm, 1.5 cm, 1 cm, and 0.5 cm produced 7.95 L, 7.30 L, 6.90 L, and 6.40 L, respectively. Consequently, the utilization of magnet fins led to a significant improvement in distiller productivity, with the best configuration being the CSD-MF-2 with a height of 2 cm, resulting in a 44.54 % increase in yield with an average overall efficiency about 42.2 %.

Bed Shear Stress and Near‐Bed Flow Through Sparse Arrays of Rigid Emergent Vegetation

AbstractVegetation is an essential component of natural rivers and has significant effects on flow and morphodynamic processes. Although progress has been made in characterizing flow resistance in vegetated flows, the impact of vegetation on bed shear stress, a key driver of sediment transport, still needs better characterization and understanding. This research, explores bed shear stress and near‐bed flow characteristics in sparse arrays of rigid emergent cylinders mimicking vegetation over a rough bed. For this purpose, a novel adaptation of a shear plate was used to measure bed shear stress at the canopy scale. These measurements were analyzed in relation to spatially averaged near‐bed flow quantities for different array densities. The results show that, for a constant water depth, the investigated cylinder canopy enhances the ratio between bed shear stress and bulk flow velocity (i.e., Darcy‐Weisbach bed friction factor) compared to unobstructed open‐channel flows, and that this ratio increases with array density. Moreover, higher near‐bed velocities were observed for higher array densities. On the other hand, no influence of the cylinder array on near‐bed values of turbulent kinetic energy and turbulent stresses was observed. Finally, it is shown that the thickness of the near‐bed layer is a suitable parameter to scale the ratio between bed shear stress and bulk flow velocity in vegetated rough bed flows.

Shifting Depth Distributions of Deep‐Sea Corals in the Southwest Pacific: Implications for Deglacial Dynamics of the Southern Ocean

AbstractWe compare depth and temporal distributions of sub‐fossil assemblages of two cold‐water scleractinian corals on seamounts in the Southwest Pacific to help define the temporal variations of water mass properties in the Southern Ocean (SO) during deglaciation. Peaks in the deep‐water abundance of the two species complement one another, with Desmophyllum dianthus peaking around the Antarctic Cold Reversal (ACR), and Solenosmilia variabilis briefly during the late Heinrich Stadial 1 (HS1) and during the Younger Dryas (YD). Environmental tolerances of the two species and the geochemistry of S. variabilis carbonate skeletons suggest that their secular distributions reflect complementary effects of temperature (higher at Antarctic Intermediate Water/Upper Circumpolar Deep Water depths during the YD and late HS1) and surface productivity (lower during the YD and HS1). Higher temperatures at depth we interpret as evidence of increased Zonal West Wind (ZWW)‐driven Ekman pumping during the late HS1 and YD, whereas coeval low surface production reflects poleward expansion of sub‐tropical water masses as a result of correlated poleward shifts of the ZWW belt and the Intertropical Convergence Zone. More broadly, a continuous deep coral population in the southwest Pacific that spans two species and three deglacial periods (HS1, ACR and the YD) and an early Holocene shift in coral distribution from deeper to shallower habitats appear to reflect large‐scale changes during deglaciation in SO temperature profiles and productivity.