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•2 min read•from Frontiers in Marine Science | New and Recent Articles

Feeding and reproduction of the tropical coastal copepod Pseudodiaptomus annandalei across warming and copper exposure levels

Our take

Understanding the feeding and reproductive dynamics of the tropical coastal copepod Pseudodiaptomus annandalei is vital as Southeast Asia confronts rapid warming and copper pollution. This study investigates how varying temperatures and copper concentrations affect adult survival, feeding, and reproductive outputs of this key zooplankton species. Results indicate that while temperature significantly influences performance, copper exposure alone shows variable effects. These findings underscore the need for integrating realistic thermal conditions into ecological risk assessments.
Feeding and reproduction of the tropical coastal copepod Pseudodiaptomus annandalei across warming and copper exposure levels

The recent study examining the feeding and reproductive behaviors of the tropical coastal copepod *Pseudodiaptomus annandalei* under conditions of warming and copper exposure sheds light on the pressing challenges facing tropical coastal ecosystems in Southeast Asia. As shallow coastal waters frequently exceed 34°C, these environments are becoming increasingly hostile to ectothermic marine life, and the concurrent rise in copper pollution—largely stemming from aquaculture and shipping activities—creates a compounded risk that is not yet fully understood. This research is critical, particularly in the context of ongoing discussions about marine health and the impacts of climate change, as highlighted in our related articles such as The digital transformation of global fisheries: a review of governance shifts and economic impacts and Responses of phytoplankton functional types to marine heatwaves in China’s marginal seas and adjacent waters.

The findings from this study are particularly notable because they reveal that while adult survival rates of *Pseudodiaptomus annandalei* were largely unaffected by copper exposure across varying temperatures, temperature itself emerged as a significant determinant of feeding and reproductive performance. Notably, optimal performance was observed at 32°C, with a sharp decline at 35°C. This suggests that even slight temperature increases could exacerbate the impact of pollutants on key species within these ecosystems. The implications are profound, as *Pseudodiaptomus annandalei* plays a crucial role in coastal food webs, serving as a primary grazer of plankton communities. If warming alters their feeding and reproductive rates, this could have cascading effects on the entire marine ecosystem, ultimately affecting biodiversity and the sustainability of fisheries.

Moreover, the study highlights the need for a nuanced understanding of how climate change can modify the effects of contaminants. The non-linear relationship between copper exposure and reproductive success at elevated temperatures indicates that ecological risk assessments must account for realistic thermal regimes and natural population variability. This is a critical consideration as we face an era of rapid environmental change, where traditional models may fall short of predicting future outcomes. As we continue to examine the impacts of human activities on marine life, the findings call for a more integrated approach to environmental management that considers both temperature fluctuations and pollution levels.

Looking ahead, the interplay between climate change and pollution will likely remain a focal point for researchers and policymakers alike. As we strive to protect and restore tropical coastal ecosystems, it is essential to foster collaborative efforts that prioritize scientific research and evidence-based policy-making. The urgency of this issue cannot be overstated, as the health of our oceans is intrinsically linked to global biodiversity and human livelihoods. As we move forward, the question remains: how will we adapt our management strategies to account for the complex interactions of warming and pollution on marine species? The answers will not only shape the future of coastal ecosystems but also our commitment to ocean stewardship in a rapidly changing world.

Tropical coastal ecosystems in Southeast Asia are facing rapid warming and increasing pollution. Shallow coastal waters now frequently exceed 34 °C, potentially pushing tropical ectotherms beyond their thermal optimum while they are simultaneously exposed to copper (Cu) contamination, especially from aquaculture and shipping activities. However, how warming alters Cu toxicity in dominant tropical zooplankton remains poorly understood. We examined the effects of Cu (0, 10, 20, 30 and 40 µg L-¹) and temperature (26, 29, 32 and 35 °C) across realistic gradients on the calanoid copepod Pseudodiaptomus annandalei, a dominant grazer of coastal plankton communities. Adult survival, cumulative faecal pellet production (as a proxy for energy intake), and cumulative nauplii production were quantified over seven days. No significant effects of temperature or Cu on adult survival were detected, likely reflecting variability among wild-collected individuals. In contrast, temperature was the main driver of feeding and reproductive performance, which peaked at 32 °C and declined at 35 °C. Cu exposure alone had no significant effects at 26 - 35 °C due to high variability in responses. At 32 °C, cumulative feeding and reproductive responses did not statistically differ among copper concentrations, whereas variability increased at both lower and higher temperatures. At 35 °C, Cu effects were non-linear, with nauplii production reduced at 30 µg Cu L-¹ but highest at 20 µg Cu L-¹, while faecal pellet production showed treatment-specific reductions, particularly in non-Cu-exposed individuals at 26 °C and in high Cu treatments at 29 and 35 °C. These findings indicate that warming can modify contaminant effects in tropical zooplankton and highlight the importance of incorporating realistic thermal regimes and natural population variability into ecological risk assessments under climate change.

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Tagged with

#climate change impact#climate monitoring#Pseudodiaptomus annandalei#tropical coastal ecosystems#warming#copper exposure#Cu toxicity#zooplankton#thermal optimum#calanoid copepod#adult survival#faecal pellet production#nauplii production#ecological risk assessments#temperature gradients#Southeast Asia#aquaculture contamination#pollution#cumulative responses#non-linear effects