Sediment Characteristics Determine the Flowering Effort of Zostera noltei Meadows Inhabiting a Human-Dominated Lagoon

Abstract

Recent studies have shown increasing Zostera noltei meadows in areas modified by anthropogenic activities. However, it is not entirely clear whether this trend of expansion could be linked to a greater reproductive effort in the species. Anthropogenic stressors can induce the reproductive effort of seagrass meadows as a response to stress, but other variables, such as seagrass biometrics or environmental factors, can also influence their sexual reproduction. To increase the knowledge regarding this issue, we monitored the flowering effort, seagrass biometrics and abiotic parameters of three Z. noltei meadows in an area that has been highly modified by anthropogenic activities during the past decades. Results showed that silt and clay content in the sediment (strongly correlated with organic matter) and seagrass vertical shoot density explained 54% of the variability in the flowering effort of the meadows. This study suggests that stress-induced flowering of Z. noltei may occur under determinate environmental conditions, such as silty environments with organic enrichment.

Reproductive Cycle of the Seagrass Zostera noltei in the Ria de Aveiro Lagoon

“…Moreover, in the year of our study, dredging activities were initiated upstream of the Mira channel, resulting in the mobilisation of fine gravel and very coarse sand along the meadows (see Figure 3C-E). On the other hand, the flowering effort of human-dominated Z. noltei meadows of Ria de Aveiro is strongly linked to silty sediments which carry high contents of organic matter [21]. Although in our study the grain size and organic matter content of the sediments were variable, relatively high values (above 2% • g DW) were found in all Z. noltei meadows throughout the study period.…”

“…Nevertheless, the reproductive capacity of the species has never been taken in consideration when evaluating its conservation status in the lagoon. A recent study suggests that there is a relationship between the reproductive effort of this species and the content of organic matter and silt in the sediment [21]. However, there are no baseline data on the phenology and germination ability of Z. noltei in Ria de Aveiro which allows us to compare the reproductive capacity of the species over time.…”

“…In southern European populations, sexual reproduction usually starts in March/April and lasts until autumn (October/November) [19], whereas at higher latitudes it starts later at the end of June [12]. Sexual reproduction in Z. noltei also differs when exposed to different environmental conditions: flowering is enhanced in areas exposed to environmental stressors such as increased hydrodynamics and organic matter enrichment, whereas stable and sheltered areas lead to reduced flowering effort [20,21]. Thus, flowering seems to be variable in this species and influenced by many environmental factors.…”

Remote sensing in seagrass ecology: coupled dynamics between migratory herbivorous birds and intertidal meadows observed by satellite during four decades

“…out as important seagrass drivers (Guerrero-Meseguer et al, 2021;Qin et al, 2021;Soissons et al, 2018); they were not considered here because of the absence of available long datasets at the required temporal resolution.…”

A One-Year Systematic Study to Assess the Microbiological Profile in Oysters from a Commercial Harvesting Area in Portugal

“…This study aimed to evaluate bacterial and viral load in Pacific oyster ( C. gigas ) flesh, intra-valvular liquid, hemolymph, outer shell surface, and farming waters during a one-year survey by analyzing the total aerobic microorganisms, marine heterotrophic bacteria, E. coli , Pseudomonas spp., Clostridium perfringens ( C. perfringens ), coagulase-positive Staphylococcus , Enterococcus spp., Salmonella spp., L. monocytogenes , molds, yeasts, norovirus (NoV), hepatitis E virus (HEV), and hepatitis A virus (HAV). The commercial oysters included in this study were farmed in Canal de Mira, one of the leading producers on the Portuguese western coast, which receives a continuous seawater and freshwater supply, but also inland drainage and treated and untreated urban wastewater [ 23 ].…”