Banca de DEFESA: CYNTHIA DAYANNE MELLO DE LIMA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CYNTHIA DAYANNE MELLO DE LIMA
DATE: 04/10/2023
TIME: 14:00
LOCAL: On-line e presencial
TITLE:

RELATIONSHIP BETWEEN MICROPLASTICS AND ZOOPLANKTON IN THE TROPICAL SOUTH ATLANTIC

KEY WORDS:

South Atlantic, estuarine plumes, microplastics, zooplankton, FTIR.

PAGES: 69
BIG AREA: Ciências Exatas e da Terra
AREA: Oceanografia
SUMMARY:

Microplastics are the predominant type of marine litter in marine ecosystems and their negative effects have been extensively reported on marine biota. This present work goal is to estimate the abundance and distribution of microplastics (MPs) and zooplankton in the Western Equatorial Atlantic (WEA) and to verify the potential impact of MPs on marine food webs in this region of the Atlantic. For this, we evaluated two regions: 1) An Environmental Protection Area (APA) with the influence of estuarine plume. Bimonthly sampling was possible under the Tamandaré Long-Term Ecological Researches Project (PELD TAMS/PE) over a year, in periods with different rainfall regimes through trawls with a 64 µm plankton net (for 5 minutes); and 2) An area of open ocean, along a latitudinal gradient. In this, the samples were obtained in the context of the Scientific Cruise SOS MAR where 18 oceanographic stations were carried out in the break of the continental shelf that covers a large part of the Northeast of Brazil. Samples at each station were obtained using Baby Bongo (64 µm) and Bongo (300 µm) nets, with hauls lasting 10 minutes. All drags were carried out on the subsurface of the water column with a Hydro-bios flowmeter attached. The samples were visually inspected in an optical stereomicroscope, and the particles were morphologically categorized. Suspected MPs particles were submitted to digestion with hydrogen peroxide (H2O2 30%) or potassium hydroxide (KOH 8%) and sodium hypochlorite (NaClO) for polymeric confirmation, and subsequently chemically analyzed with Fourier Transform Infrared Spectroscopy (FTIR). The predominant type of floating microplastics are fibers, mainly in more oceanic areas (95%). Our results demonstrate that the concentration of microplastic varies spatially in coastal areas close to rivers, confirming the importance of rivers as a source of microplastics in the ocean, especially in periods of high rainfall. We registered an average concentration of MPs 2 times higher in the samples with a 64µm mesh (5.05 ± 3.73 particles/m³), when compared with the 300µm mesh (2.09 ± 2.77 particles/m³). In more oceanic regions, meroplankton have higher encounter rates when compared to holoplankton and there is a correlation between the total zooplankton and the abundance of PMs, although it is not significant. The data generated in this thesis help to understand the real concentrations of PMs in marine environments and that threaten the marine food web.

COMMITTEE MEMBERS:
Interno - 1355829 - JOSE SOUTO ROSA FILHO
Externo à Instituição - JOSÉ EDUARDO MARTINELLI FILHO - UFPA
Externo à Instituição - MARCELO DE OLIVEIRA SOARES - UFC
Externo à Instituição - MAURO DE MELO JÚNIOR - UFRPE
Interno - 2330768 - PEDRO AUGUSTO MENDES DE CASTRO MELO
Presidente - 2130453 - SIGRID NEUMANN LEITAO