Banca de DEFESA: SUELEN NASCIMENTO DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: SUELEN NASCIMENTO DOS SANTOS
DATA : 22/04/2026
HORA: 09:00
LOCAL: Auditório do DOCEAN (Híbrida)
TÍTULO:

 

Acumulação ativa e passiva de microplástico em organismos bentônicos marinhos na costa de Pernambuco

 

PALAVRAS-CHAVES:

Bentos, recife, poluição, oceano, molusco, crustáceo, macroalga, esponja

PÁGINAS: 172
RESUMO:

Microplastic pollution has emerged as one of the most pervasive environmental issues affecting
marine ecosystems worldwide. Due to their small size and persistence, microplastics are now
detected across virtually all marine habitats, raising increasing concern about their potential
impacts on marine organisms and food webs. Despite the growing number of studies on this
topic, the ecological processes that regulate the accumulation of microplastics in benthic
environments remain poorly understood, particularly in tropical coastal ecosystems where data
are still limited. This thesis investigated both active and passive pathways of microplastic
accumulation in marine benthic organisms and environmental matrices along the coast of
Pernambuco, northeastern Brazil. By integrating literature synthesis, field-based ecological
studies, methodological innovation, and analyses of environmental drivers, this work provides
a comprehensive assessment of microplastic dynamics in tropical coastal systems. The first
chapter presents a systematic review examining whether feeding mechanisms influence
microplastic accumulation in marine benthic organisms. Following PRISMA guidelines, the
analysis revealed a strong taxonomic bias in the current literature, with bivalves representing
76.67% of all published studies. Nevertheless, the review also showed that other benthic taxa
may accumulate substantially higher concentrations of microplastics. For example, reported
values for sponges ranged from 91 to 612 particles g⁻¹ dry weight, while polychaetes ranged
from 1 to 880 particles g⁻¹ wet weight. Although feeding strategies appear to influence particle
retention, methodological heterogeneity among studies (I² > 95%) prevents robust quantitative
comparisons and highlights the urgent need for standardized analytical protocols in
microplastic research. Chapter two investigates the role of reef-forming benthic organisms as
potential sinks for microplastics in tropical coastal environments. The results demonstrate that
biogenic reefs formed by Brachidontes exustus and Petaloconchus spp. function as structural
traps that enhance particle retention within the benthic habitat. Microplastic concentrations
were considerably higher in reefs formed by B. exustus (51.7 ± 65.6 particles per 100 g of reef
during the dry season and 67.0 ± 72.8 during the rainy season) compared
with Petaloconchus reefs (4.7 ± 4.6 and 7.3 ± 6.8 particles per 100 g of reef in the dry and rainy
seasons, respectively). Microfibers represented 53.33% of all detected particles, and 73% of
these fibers were transparent, suggesting a strong contribution from textile-derived pollution
sources. Chapter three presents the development of a low-cost ultraviolet fluorescence
detection system (UV-Studio) designed to improve the visualization of microplastics in
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environmental samples. The device enhances the detection of Nile Red–stained particles while
minimizing interference from ambient light, providing a simple and accessible screening tool
for laboratories with limited analytical infrastructure. In chapter four, this system was applied
to assess microplastic contamination in the barnacle Tetraclita stalactifera. Fluorescence-based
detection significantly improved the identification of microplastic particles when compared
with traditional white-light observation. Statistical analysis confirmed a significant increase in
detection efficiency under ultraviolet illumination (t = 2.26, p = 0.03). These results
demonstrate that combining Nile Red staining with low-cost fluorescence systems represents a
practical approach for rapid screening of microplastics in biological tissues. Chapter five
evaluates passive microplastic accumulation in sediments and macroalgae collected from
coastal environments subjected to different levels of anthropogenic influence. Microplastics
were detected in all analyzed samples, confirming their widespread occurrence in benthic
habitats. Fibers were the dominant particle type, accounting for 53.33% of the total
microplastics identified, further supporting the importance of textile-related sources in coastal
contamination. Sediment samples showed slightly higher concentrations of certain polymers,
consistent with their role as long-term sinks for plastic debris in marine environments. Finally,
chapter six examines whether seasonal variability or species identity plays a stronger role in
determining the occurrence of microplastics in benthic organisms. The results indicate that
biological traits contribute to particle retention, but environmental factors, particularly seasonal
runoff during the rainy period, also influence microplastic availability and exposure.
Interestingly, polymer composition remained relatively consistent across seasons and sampling
sites, suggesting the presence of continuous regional inputs rather than isolated contamination
events. Taken together, the findings presented in this thesis demonstrate that microplastic
accumulation in tropical coastal ecosystems results from complex interactions between
biological traits, habitat structure, environmental matrices, and hydrodynamic processes. The
results also highlight the role of benthic organisms and biogenic reefs as important retention
structures for microplastics. In addition, the development of accessible analytical tools and the
need for methodological standardization are emphasized as key steps toward improving
environmental monitoring. By providing new baseline data and methodological advances for
the Southwestern Tropical Atlantic, this work contributes to a better understanding of
microplastic dynamics and supports ongoing efforts to mitigate plastic pollution in marine
environments.

 

MEMBROS DA BANCA:
Presidente - 1355829 - JOSE SOUTO ROSA FILHO
Interna - 1286817 - MONICA FERREIRA DA COSTA
Externo à Instituição - ISABEL MARÍN BELTRÁN
Externo à Instituição - ALEXANDER TURRA
Externo à Instituição - JANDYSON MACHADO SANTOS