Zooplankton abundance during summer in the Bay of La Paz (southwestern Gulf of California, Mexico)

Abstract

Marine zooplankton play key roles in the transfer of energy to higher trophic levels and the removal of CO2 from the atmosphere through the sedimentation of inorganic and organic carbon compounds included in their fecal pellets. Therefore, differences in the zooplankton groups driven by climate variations could influence the biogeochemical cycles at large oceanic scales. As a contribution to this topic, we analyzed the zooplankton groups in the Bay of La Paz, Gulf of California, Mexico, a highly dynamic basin characterized by its high biological productivity. We used information gathered during multidisciplinary research cruises in the summers of 2008 and 2009. The results showed differences in the hydrographic parameters between both summers, with a higher temperature recorded in 2009. The zooplankton groups showed that the calanoid copepods were the most abundant; however, there were important differences in the relative abundance of the rest of the analyzed groups as an effect of the temperature distribution along the study area, which was confirmed by multivariate statistical methods. These temperature changes were associated with increased gelatinous zooplankton (Cnidaria, Chaetognatha, Appendicularia, and Ctenophora) in 2009 in a region where the temperature was higher, possibly as a result of changes in food (phytoplankton) availability.

Influencia de un giro ciclónico y un frente termohalino en la estructura poblacional de Centropages furcatus en la bahía de La Paz, golfo de California

“…The results of this study showed that the entry of water from the Gulf of California with maximum velocity values in the northern part of Boca Grande and the outflow of water near the Islands Espíritu Santo and Roca Partida produced the cyclonic circulation, which coincides with what was reported by Coria-Monter et al (2017), Durán-Campos et al (2019), Coria-Monter et al (2020), and Rocha-Díaz et al (2022. Monreal-Gómez et al (2001) reported that the cyclonic gyre in the Boca Grande area is produced, in part, by the exchange of water masses with the Gulf of California.…”

Variabilidad estacional de la biomasa de copépodos en un vórtice ciclónico en la bahía de la Paz, sur del golfo de California, México

“…Nosotros concluimos que la identificación de los copépodos a nivel de grupo contribuye al conocimiento de su ecología, ya que nos permitió visualizar patrones de distribución en un vórtice ciclónico y determinar la relación que guarda con la concentración de Cla. Investigaciones anteriores han demostrado que la identificación del zooplancton marino a nivel de grupo es suficiente para evaluar aspectos de ecología trófica y patrones de distribución de los organismos de diferentes regiones alrededor del mundo (e.g., Ayón et al 2008), particularmente en la BP (e.g., Durán-Campos et al 2015Coria-Monter et al 2020). Los copépodos separados de las muestras se colocaron en una caja de petri de vidrio y se dividieron en 3 grupos: copépodos calanoides, copépodos ciclopoides y copepoditos (todos los estadios).…”

“…Las corrientes geostróficas (u, v) se calcularon a partir de los datos del CTD de acuerdo con Pond y Pickard (1995): Se obtuvieron imágenes satelitales de la concentración de Cla, como un indicador de la biomasa del fitoplancton, en las fechas que se realizaron ambos cruceros de investigación. Las imágenes, con una resolución de 1 km píxel, fueron at the group level is enough for the assessment of trophic ecology and distribution patterns in different domains around the globe (e.g., Ayón et al 2008), particularly in the BoP (e.g., Durán-Campos et al 2015Coria-Monter et al 2020). The copepods picked from the samples were pooled in a glass Petri dish and divided into 3 groups: calanoid copepods, cyclopoid copepods, and all copepodite stages.…”

Vertical distribution patterns of chlorophyll-a during autumn in a coastal environment inside the Gulf of California

“…1). The bay represents a place of refuge, growth and feeding for numerous species, some of them threatened or endangered, and as a whole, the region is recognized for its high biological diversity as a result of their hydrodynamic, which includes the presence of a quasi-permanent cyclonic eddy that induces an Ekman pumping that positively impacts the phytoplankton communities (Coria-Monter et al 2017), and thus triggers a bottom-up mechanism that influences the organisms positioned in the highest trophic levels of the food chain (Coria-Monter et al 2020). Besides, the presence of additional physical processes at different scales has been related to the high biological diversity that the bay supports, including hydraulic jumps (Rocha-Díaz et al 2021) and the propagation of internal waves (Coria-Monter et al 2019), which raise nutrients towards the euphotic zone, which benefits phytoplankton communities.…”