The end of resilience: Surpassed nitrogen thresholds in coastal waters led to severe seagrass loss after decades of exposure to aquaculture effluents

Thomsen, Esther; Herbeck, Lucia S.; Jennerjahn, Tim C

doi:10.1016/j.marenvres.2020.104986

Cited by 54 publications

(32 citation statements)

References 71 publications

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“…In fact, T. hemprichii, and not C. serrulata, was present in a highly eutrophic seagrass meadow in the Stone Town area (Zanzibar Archipelago, Tanzania), confirming that the former species have higher tolerance to these conditions even under long-term natural conditions (Teichberg et al, in preparation). Similarly, T. hemprichii was pointed as the most persistent species in other highly impacted seagrass meadows in China (Thomsen et al, 2020). Therefore, the unequal effect of eutrophication in different species might cause a biodiversity loss in tropical seagrass meadows.…”

Section: Ecological Implicationsmentioning

confidence: 97%

“…It presents faster shoot turnover and growth than the two other species ( Duarte, 1991 ). All three species have been observed to tolerate different trophic conditions ( Van Tussenbroek et al, 2016 ; Mwaura et al, 2017 ; Thomsen et al, 2020 ; Teichberg et al, in preparation ) and adverse maximum temperatures ( Campbell et al, 2006 ; Georgiou et al, 2016 ; Pedersen et al, 2016 ; Collier et al, 2017 ; George et al, 2018 ; Anton et al, 2020 ; Nguyen et al, 2020 ; Winters et al, 2020 ; Beca-Carretero et al, accepted). Furthermore, T. hemprichii, C. serrulata and H. stipulacea show differences in their life-history traits representing permanent, opportunistic and colonizing strategies, therefore different resistance and responses to stressors might be expected ( O’Brien et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

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Species-Specific Trait Responses of Three Tropical Seagrasses to Multiple Stressors: The Case of Increasing Temperature and Nutrient Enrichment

2020

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Seagrass meadows are declining globally. The decrease of seagrass area is influenced by the simultaneous occurrence of many factors at the local and global scale, including nutrient enrichment and climate change. This study aims to find out how increasing temperature and nutrient enrichment affect the morphological, biochemical and physiological responses of three coexisting tropical species, Thalassia hemprichii, Cymodocea serrulata and Halophila stipulacea. To achieve these aims, a 1-month experiment under laboratory conditions combining two temperature (maximum ambient temperature and current average temperature) and two nutrient (high and low N and P concentrations) treatments was conducted. The results showed that the seagrasses were differentially affected by all treatments depending on their lifehistory strategies. Under higher temperature treatments, C. serrulata showed photoacclimation strategies, while T. hemprichii showed decreased photo-physiological performance. In contrast, T. hemprichii was resistant to nutrient over-enrichment, showing enhanced nutrient content and physiological changes, but C. serrulata suffered BG nutrient loss. The limited response of H. stipulacea to nutrient enrichment or high temperature suggests that this seagrass is a tolerant species that may have a dormancy state with lower photosynthetic performance and smaller-size individuals. Interaction between both factors was limited and generally showed antagonistic effects only on morphological and biochemical traits, but not on physiological traits. These results highlight the different effects and strategies co-inhabiting seagrasses have in response to environmental changes, showing winners and losers of a climate change scenario that may eventually cause biodiversity loss. Trait responses to these stressors could potentially make the seagrasses weaker to cope with following events, due to BG biomass or nutrient loss. This is of importance as biodiversity loss in tropical seagrass ecosystems could change the overall effectiveness of ecosystem functions and services provided by the seagrass meadows.

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Section: Ecological Implicationsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Species-Specific Trait Responses of Three Tropical Seagrasses to Multiple Stressors: The Case of Increasing Temperature and Nutrient Enrichment

2020

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“…High nutrients inside wastewater can also cause pollution when released directly to water bodies. The high concentration of nutrients is a major cause of eutrophication in the aquatic environment (Thomsen et al, 2020). Eutrophication promotes the growth of floating macrophytes, which limits the amount of sunlight penetrating into the underwater (Lusiana et al, 2020).…”

Section: Aquaculture Wastewater Characteristicsmentioning

confidence: 99%

Potential of valuable materials recovery from aquaculture wastewater: An introduction to resource reclamation

Kurniawan

Abdullah

Imron

et al. 2021

Aquaculture Research

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Aquaculture wastewater has become a global concern, especially to the aquatic environment. Aquaculture industries rely on the consumption of water and generate an abundant amount of wastewater. Aquaculture wastewater has characteristics of high organic materials and nutrients. However, the potential of resource reclamation from this wastewater awaits to be explored further. Aquaculture wastewater contains algae, which can be harvested using biodegradable coagulants for further utilization. It is also nutrient‐rich and can be reclaimed as fertilizer or used as co‐cultivation of algae. However, limited research has focused on the potential of valuable materials recovery from aquaculture wastewater. This review paper discusses the estimation of wastewater generation from aquaculture industries and the characteristics of the effluent. It discusses the potential for valuable material recovery from wastewater, including aquaculture industries wastewater. This paper summarizes several valuable materials that can be recovered from wastewater to achieve cleaner production in industrial processes and discusses the challenges and prospects in recovering valuable materials from aquaculture effluent for future applications. This review could provide insights to increase the economic value of wastewater, especially aquaculture wastewater, and to enrich knowledge related to the resource reclamation from wastewater.

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“…The basin is influenced by a tropical monsoon climate with the dry season from November to April and the wet season from May to October. Mangrove that used to be the dominant landform of the WRE, shrank so far over 70%, mainly due to aquaculture activities in recent decades (Thomsen et al, 2020). The aquaculture ponds were built mainly for shrimps.…”

Section: Study Areasmentioning

confidence: 99%

Tracing Nutrients and Organic Matter Changes in Eutrophic Wenchang (China) and Oligotrophic Krka (Croatia) Estuaries: A Comparative Study

et al. 2021

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Estuaries modify the concentration and composition of riverine nutrients and organic matter (OM), which eventually determine the riverine flux effect to coasts. Nutrients, organic carbon (OC), pigments, and amino acids (AAs) from the samples collected in the eutrophic Wenchang River Estuary (WRE) in China and the oligotrophic Krka River Estuary (KRE) in Croatia were analyzed in order to have a better understanding of how estuaries regulate terrestrial materials. We found a clear increase of dissolved inorganic nitrogen (DIN) concentration and its subsequent decrease due to the removal of DIN (over 100 μM) in the WRE, whereas DIN showed minor variation lengthwise in the KRE, i.e., with the salinity changes, ranging between 1.0 and 5.8 μM. The elevated algae-derived OC, dissolved organic nitrogen, and particulate AAs nitrogen suggest that the OM assimilation may explain approximately one-third of the DIN removal in the WRE, whereas in the oligotrophic KRE, such inorganic to organic transformation is not likely to be significant. Due to the prominent estuarine nitrogen removal/assimilation process, DIN/dissolved inorganic phosphorus (DIP) ratio was as high as 425 in the upper WRE under strong riverine influence, but it declined to as low as 5.4 at the mouth of WRE, that is even lower than DIN/DIP ratio at the mouth of oligotrophic KRE (12). When compared with other rivers worldwide, the Wenchang River showed high nutrients and organic carbon yields. Given the contrasting estuarine process (e.g., DIN removal) between the KRE and the WRE, apparent high nutrient yield from eutrophic rivers should be viewed with caution in ocean studies as the final impact to coastal zone could be similar to the oligotrophic rivers like the KRE.

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The end of resilience: Surpassed nitrogen thresholds in coastal waters led to severe seagrass loss after decades of exposure to aquaculture effluents

Cited by 54 publications

References 71 publications

Species-Specific Trait Responses of Three Tropical Seagrasses to Multiple Stressors: The Case of Increasing Temperature and Nutrient Enrichment

Species-Specific Trait Responses of Three Tropical Seagrasses to Multiple Stressors: The Case of Increasing Temperature and Nutrient Enrichment

Potential of valuable materials recovery from aquaculture wastewater: An introduction to resource reclamation

Tracing Nutrients and Organic Matter Changes in Eutrophic Wenchang (China) and Oligotrophic Krka (Croatia) Estuaries: A Comparative Study

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