Microplastics and nanoplastics (NMPs) are considered one of hazardous contaminants in marine ecosystems due to their toxic effects, such as reproduction disorder and oxidative stress, on marine organisms. Although water temperature is rising due to global climate change, little information on the toxicological interaction between NMPs and temperature is available. Therefore, in this study, we confirmed the toxicity of NMPs (polystyrene [PS] beads; 0.05- and 6-μm) on brackish water fleas (Diaphanosoma celebensis) depending on increased temperature (30°C and 35°C) at individual and molecular levels. In the chronic toxicity test, the group exposed to high temperatures showed an earlier first reproduction time compared to the normal temperatures group, but it was delayed by co-exposure to NMPs at 35°C. Notably, the total reproduction decreased significantly only after 0.05-μm PS beads exposure at 30°C. Interaction analysis showed that first reproduction time, modulation of the antioxidantrelated gene (GSTS1), heat shock gene (Hsp70), and ecdysteroid pathway-related genes (EcR_A, EcR_B, and CYP314A1) were closely related to temperature and PS beads size. These results indicate that microplastics have size-dependent toxicity, and their toxicity can be enhanced at high temperatures. In addition, higher temperatures and PS beads exposure may have negative effects on reproduction. This study suggests that various factors such as water temperature should be considered when evaluating the toxicity of microplastics in marine ecosystems, and provides an understanding of the complex toxic interaction between water temperature and microplastics for marine zooplankton.

1. 서 론
2. 재료 및 방법
    2.1. 시험생물
    2.2. 시험용액 제조
    2.3. 노출시험
    2.4. 생식지표 및 개체군 성장률 관찰
    2.5. Total RNA 추출 및 cDNA 합성
    2.6. Quantitative real-time polymerase chainreaction (qRT-PCR)
    2.7. 통계분석
3. 결과 및 고찰
    3.1. 온도와 PS beads의 만성 노출이 생식지표와개체군 성장률에 미치는 영향
    3.2. 온도 및 PS beads의 급성 노출이 항산화 효소,스트레스, 생식 경로 관련 유전자 발현에미치는 영향
    3.3. 생식지표, 성장률, 유전자 발현과 온도 및PS beads 크기 사이의 상호작용 효과
4. 결 론
적 요
CRediT authorship contribution statement
Declaration of Competing Interest
REFERENCES

• 이윤하(상명대학교 융합공과대학 생명공학전공) | Youn-Ha Lee (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea)
• 박종석(상명대학교 융합공과대학 생명공학전공) | Jong-Seok Park (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea)
• 박채린(상명대학교 융합공과대학 생명공학전공) | Chaerin Park (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea)
• 조상현(상명대학교 융합공과대학 생명공학전공) | Sang-Hyun Cho (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea)
• 유제원(상명대학교 융합공과대학 생명공학전공) | Je-Won Yoo (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea)
• 이영미(상명대학교 융합공과대학 생명공학전공) | Young-Mi Lee (Department of Biotechnology, College of Convergence Engineering, Sangmyung University, Seoul 03016, Republic of Korea) Corresponding author