Tropical cyclones (TCs) are natural systems that develop over ocean basins and are key components of the atmospheric activity during the warm season. However, there are still knowledge gaps about the combined positive and negative TC impacts on the structure and function of coastal socio-ecosystems. Using remote sensing tools, we analyzed the frequency, trajectory, and intensity of 1894 TCs from 1851–2019 to identify vulnerable “hotspots” across the Yucatan Peninsula (YP), Mexico. A total of 151 events hit the YP, with 96% of landings on the eastern coast. We focused on three major hurricanes (Emily and Wilma, 2005; Dean, 2007) and one tropical storm (Stan, 2005) to determine the impacts on cumulative precipitation, vegetation change, and coastal phytoplankton (Chl-a) distribution across the YP. Despite a short inland incursion, Wilma’s environmental damage was coupled to strong winds (157–241 km/h), slow motion (4–9 km/h), and heavy precipitation (up to 770 mm). Because of an extensive footprint, Wilma caused more vegetation damage (29%) than Dean (20%), Emily (7%), and Stan (2%). All TCs caused a Chl-a increase associated to submarine discharge and upwelling off the peninsula coastlines. Disaster risk along the coast underscores negative economic impacts and positive ecological benefits at the regional scale.
The use of information of net primary productivity (NPP) from remote ocean color sensors is increasingly common in marine sciences. The resulting information has been used to explain variations in productivity at different spatio-temporal scales and in the presence of climate phenomena, such as the El Niño Southern Oscillation, and global warming. Satellite remote sensing data were analyzed in Bahía de La Paz (BLP), Mexico, to determine the spatio-temporal variation in NPP. In addition, in situ hydrographic data were obtained to characterize the water properties in the bay. The satellite data agree with in situ measurements, validating the satellite observations over this region. The NPP generally presented seasonal variation with maximum values in winter-spring and minimum values in summer–autumn. The variance explained by NPP from the measured variables was ranked as Chl-a < DEN < SST < PAR < WSC. The highest NPP values generally occurred when subtropical subsurface (SsStW) water was relatively shallow. Due to divergence and mixing processes, this water provided nutrients to the euphotic zone, and consequently an increase in NPP and changes in plankton biomass were observed. The annual trends of the variation in hydrographic data with respect to that of remote sensing data were similar; however, it is necessary to increase the number of data validation studies. The remote sensing and in situ measurements allowed for the main biophysical variables that modulate NPP in different time scales to be identified. The satellite-derived NPP data classifies the BLP as a high productivity zone with 432 g C m year. The use of satellite NPP data is satisfactory and should be incorporated into marine primary productivity studies.
1 November 2021 in Regional Studies in Marine Science
This study analyzed seasonal and interannual variations in larval fish abundance in Cabo Pulmo National Park (CPNP) from January 2015 to November 2017, encompassing the 2015–2016 El Niño and subsequent thermal relaxation, to examine the impacts of climate-driven events on larval fish abundance, diversity, and species richness in a no-take marine protected area. A total of 166 larval fish taxa were identified, spanning 59 families, 94 genera and 98 species. Dactyloscopidae spp. (relative frequency: 41.7%; abundance: 9.9%), Auxis spp. (32.3%, 7.3%), Abudefduf troschelii (24%, 4.7%), Syacium spp. (17.7%, 3.9%) and Tripterygiidae spp. (12.5%, 2.8%) were the most frequent and numerically dominant taxa, after excluding 13 mesopelagic and bathypelagic species not typically found in CPNP’s shallow waters as adults. Although larval fish assemblages responded to short-term seasonal fluctuations (quarterly and semi-annual), we found that fish larvae abundance, diversity and species richness (independently of their biogeographic and habitat affinity) declined during the 2015–2016 El Niño compared to both the period before El Niño and the subsequent thermal relaxation (June 2016–November 2017). These findings highlight their vulnerability to El Niño-driven oceanographic changes, with implications for the resilience of these populations in the context of a changing climate.
16 December 2020 in Revista de biología marina y oceanografía
During 2013-2015 a patch of warm water called Warm Blob appeared in the northeastern Pacific, producing several effects at biological and physical level. This event appears to be unique, however, evidence was encountered for another three events similar to the recent Warm Blob event during the period from 1854 to 2017 through analyzing the historical anomalies of the SST anomalies in the Pacific Ocean. Each event showed the same distinctive Warm Blob spatial pattern —firstly, a patch of warm water develops in the northern Pacific south of Alaska, and gradually spreads southward along the coast reaching up to Baja California Peninsula”. During the 2013-2015 event, this warm water patch raised the seawater temperature anomalies above 0.5 °C, with a maximum of 4 °C. The other past events obtained in the time series analysis occurred in 1874, 1936 and 1962 and lasted around 18-24 months each. Each warming event is described, showing that the most intense was the 2013-15, followed by the 1935-36. The results suggest a periodicity of occurrence of 25 to 60 years that can also be traced on the biology of the region. These findings propose that such warmings are part of the climatic variability in the northeastern Pacific and should be studied with more detail to determine its cause.