Will hypolimnetic waters become anoxic in all deep tropical lakes?

Fukushima, Takehiko; Matsushita, Bunkei; Subehi, Luki; Setiawan, Fajar; Wibowo, Hardianto

doi:10.1038/srep45320

Cited by 30 publications

(18 citation statements)

References 24 publications

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“…High-frequency measurement enables a better understanding of the dynamic nature of dissolved oxygen, which had not previously been documented using traditional discrete sampling, particularly in Lake Maninjau. Monthly and weekly, even daily, oxygen observations might be able to capture trends of seasonal concentration and give the general idea of the ongoing condition of the lake (Fukushima et al, 2017). However, these techniques could not provide a better picture of the process involved in concentration dynamics (Lukman et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Oxygen depletion in the water column may therefore occur in any instance. Despite the importance of the weather-induced physical process that enables the transport of anoxic (DO < 0.2 mg L -1 ) hypolimnion water to move upward (Santoso et al, 2018;Fukushima et al, 2017), heterotrophic metabolism oxygen demand in Lake Maninjau depletes surface DO at a rate of 12.1 mg O2 L -1 d -1 . In fact, primary productivity in the lake only produces DO of 9.0 mg O2 L -1 day -1 .…”

Section: Discussionmentioning

confidence: 99%

“…Lake Maninjau has been crowded by in-lake aquaculture for years, hence, there is a consequence of high demand of oxygen for the system. Despite the hydrodynamic force in moving the anoxic bottom water upward to the surface (Santoso et al, 2018;Fukushima et al, 2017), oxygen demand by heterotrophs for respiration (including inorganic material oxidation and organic matter decomposition) may also be substantial in reducing DO availability in the epilimnion.…”

Section: Introductionmentioning

confidence: 99%

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Ecosystem Metabolism and Oxygen Deficit in Lake Maninjau: Insight From High-Frequency Measurement

Santoso

Triwisesa

2020

Limnotek : Perairan Darat Tropis Di Indonesia

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High-frequency measurement provides a sophisticated insight in capturing environmental patterns. Compared to traditional discrete measurement, high-frequency sensors allow a better understanding of any processes particularly those with temporal scale characteristics. Lake metabolism is one of the exemplars getting advantage of such better resolution measurement. The dynamics of dissolved oxygen concentration (DO) observed in an hourly manner, even in minutes, may explain the balance of photosynthetic activity as expressed by gross primary production (GPP), respiration (R), and atmospheric exchange. Using a coupled thermistor-chain and oxygen sensor, we computed lake metabolism of the eutrophic Lake Maninjau. Characterized by high phytoplankton productivity fueled by the abundance of nutrient availability, DO concentration in Lake Maninjau is likely to be supersaturated. On the other hand, floating cage aquaculture operated in the lake may have a consequence in increasing water column heterotrophy, that is oxygen demanding community. Through a simple mathematical model, we revealed that water column respiration in Lake Maninjau is higher than gross primary production (R > GPP) with an average of 12.1 mg O2 L-1 day-1 and 9.0 mg O2 L-1 day-1 , respectively. Our findings highlight that as heterotrophy in eutrophic lakes may relatively be high, oxygen depletion in the water column may occur in any instance, especially in lakes where dense floating cage aquaculture is in place.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ecosystem Metabolism and Oxygen Deficit in Lake Maninjau: Insight From High-Frequency Measurement

Santoso

Triwisesa

2020

Limnotek : Perairan Darat Tropis Di Indonesia

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“…While figure 1 provides a rough national outline, PT Hatfield has developed a more detailed map for the suitability of shrimp farms that also accounts for urban sprawl (https:// aquaculture.ipb.ourecosystem.com/interface/). Complementing assessments should be carried out for freshwater lakes, as many of these already have exceeded carrying capacity (Fukushima et al 2017). Competition for resources with other sectors also needs to be further developed, as everyone has their own ambitious targets.…”

Section: Discussionmentioning

confidence: 99%

Indonesian aquaculture futures—identifying interventions for reducing environmental impacts

Henriksson

Banks

Suri

et al. 2019

Environ. Res. Lett.

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Indonesia is the world's second largest producer and third largest consumer of seafood. Fish is therefore essential to the nation, both financially and nutritionally. Overfishing and the effects of climate change will, however, limit future landings of capture fisheries, so any increases in future seafood production will need to come from aquaculture. The ecological effects of aquaculture are dependent upon the choice of species, management, and where it is sited. In the present study we use life cycle assessment (LCA) to evaluate how possible interventions and innovations can mitigate environmental impacts related to the aquaculture sector's growth. The mitigation potential of six interventions were also quantified, namely (1) FCR reductions for whiteleg shrimp, carp, and tilapia;(2) sustainable intensification of milkfish and Asian tiger shrimp polyculture; (3) shifting groupers from whole fish diets to pellets; (4) favoring freshwater finfish over shrimp; (5) renewable electricity; and (6) reduced food waste and improved byproduct utilization. If all six interventions are implemented, we demonstrate that global warming, acidification, eutrophication, land occupation, freshwater use, and fossil energy use could be reduced by between 28% and 49% per unit of fish. The addition of many innovations that could not be quantified in the present study, including innovative feed ingredients, suggest that production could double within the current environmental footprint. This does not, however, satisfy the expected 3.25-fold increase under a business-as-usual scenario, neither does it satisfy the government's growth targets. We therefore also explore possible geographical areas across Indonesia where aquaculture expansions and ecological hotspots may conflict. Conclusively, we advocate more conservative production targets and investment in more sustainable farming practices. To accelerate the implementation of these improvements, it will be central to identify the most cost-effective aquaculture interventions.

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“…In general, the DO deficit is expected to grow owing to eutrophication and warming 1 . Similarly, hypolimnetic waters have been reported to become anoxic in deep tropical lakes 6 . In response to these changes, a number of diverse approaches have been adopted to investigate the temporal dynamics and spatial patterns of hypoxia in European lakes and coastal regions 2 .…”

Section: Introductionmentioning

confidence: 95%

Factors explaining the yearly changes in minimum bottom dissolved oxygen concentrations in Lake Biwa, a warm monomictic lake

Fukushima

Inomata

Komatsu³

et al. 2019

Sci Rep

Self Cite

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Vertical profiles of dissolved oxygen (DO) and water temperature (WT) measured bi-monthly for 36 years (1980–2015) near the deepest part of a warm monomictic lake were analyzed with special reference to yearly minimum DO at bottom (DOmin). DOmin changed yearly (3.0 ± 1.2 mg l−1) and significant differences in DOmin were not observed between Period I (1980–1993; cooler and worse in water quality) and Period II (1994–2015; warmer and better in water quality). This unclear trend in DOmin was probably due to the offsetting influences between warming induced by global warming and oligotrophication attempted by local governments etc. for the study period. DOmin was positively correlated with disturbance time (timing of last cold water intrusion observed from Mar to Aug), which could be related to the start of DO depletion at bottom. Thus, the linear model using this parameter could predict yearly DOmin fairly well for the entire study period (r2 = 0.60). In addition, DOmin and time of disturbance were correlated negatively with water density at bottom in Jan and positively with water density equilibrated to air temperature (AT) in Mar. Higher lake water density after full depth mixing advances the disturbance time. In contrast, lower AT in Mar and/or higher density of influent water after Mar delays the time likely due to the larger amount of snowfall in the watershed. Further, DOmin was positively correlated with maximum wind velocity in Sep which probably induced the recovery of DO. Multiple-regression models to predict DOmin using these meteorological and water quality parameters were developed (r2 ≥ 0.38, worse performances than the model using disturbance time) to forecast future trends of DOmin through global warming and/or climate change. Significant influences of water or sediment oxygen demands on DOmin were not detected. We also discuss the applicability of the proposed models.

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Will hypolimnetic waters become anoxic in all deep tropical lakes?

Cited by 30 publications

References 24 publications

Ecosystem Metabolism and Oxygen Deficit in Lake Maninjau: Insight From High-Frequency Measurement

Ecosystem Metabolism and Oxygen Deficit in Lake Maninjau: Insight From High-Frequency Measurement

Indonesian aquaculture futures—identifying interventions for reducing environmental impacts

Factors explaining the yearly changes in minimum bottom dissolved oxygen concentrations in Lake Biwa, a warm monomictic lake

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