The Aptian–Albian interval represents a time of distinctive atmospheric and oceanic changes. A major perturbation of the carbon cycle induced by intense volcanic activity produced episodes of environmental change affecting the abundance and evolution of marine plankton. Several studies based on pelagic and hemipelagic sections have used biostratigraphic events and carbon isotope stratigraphy tools to identify biotic responses to environmental perturbations. Few studies have included Aptian–Albian planktic microfossil communities and paleoenvironmental changes in Mexico, a region that was part of the western proto-North Atlantic margin. The aim of this study is to interpret paleoenvironmental and paleoceanographic conditions through a microfacies analysis of a carbonated succession of the Tamaulipas Formation from central-eastern Mexico (Tampico-Misantla Basin), within a temporal framework based on planktic foraminiferal and colomiellids biostratigraphy.

The studied section, 92 m thick, consists of a continuous pelagic succession. Facies contain abundant planktic microfossils and span the stratigraphic interval between the Globigerinelloides blowi and Ticinella praeticinensis Zones. The Aptian/Albian Boundary in the studied section was established on the highest occurrence (HO) of planktic foraminifera such as Paraticinella rohri and the presence of Microhedbergella spp., followed by the lowest occurrence (LO) of colomiellids such as Colomiella recta.

Detailed quantification of microfossil assemblages reveals variations in abundance of planktic foraminifera, radiolarians, praecolomiellids, colomiellids, dinocyst and echinoderm fragments. These variations related to fabric characterization and bioturbation indexes allow us to infer fluctuations in ancient trophic conditions in the water column, which might be associated with episodes of global environmental change such as Oceanic Anoxic Events.

Aptian-Albian 间隔代表了一个独特的大气和海洋变化时期。由强烈火山活动引起的碳循环的主要扰动产生了影响海洋浮游生物丰度和演化的环境变化事件。几项基于远洋和半远洋剖面的研究使用生物地层事件和碳同位素地层学工具来确定生物对环境扰动的反应。很少有研究包括墨西哥的 Aptian-Albian 浮游微化石群落和古环境变化，该地区是西部原始北大西洋边缘的一部分。

研究部分厚 92 m，由连续的远洋序列组成。相包含丰富的浮游微化石，跨越Globigerinelloides blowi和Ticinella praeticinensis带之间的地层区间。研究部分中的 Aptian/Albian 边界建立在浮游有孔虫（如Paraticinella rohri）的最高发生率 (H2O)和Microhedbergella spp.的存在上，其次是Colomiella recta的最低发生率 (LO) 。

微化石组合的详细量化揭示了浮游有孔虫、放射虫、原虫、结肠虫、双囊虫和棘皮动物碎片丰度的变化。这些与织物特征和生物扰动指数相关的变化使我们能够推断水体中古代营养条件的波动，这可能与全球环境变化事件（例如海洋缺氧事件）有关。