My research focuses on socio-ecological systems within fishery cooperatives in Baja California, Mexico, exploring their resilience and adaptation strategies to climate change and COVID-19 impacts through oceanographic and ecological monitoring.
Fiorenza Micheli, Postdoctoral Faculty Sponsor
Assemblages of pelagic thaliaceans in oceanographic features at the tropical-temperate transition zone of a western boundary current.
Journal of plankton research
2023; 45 (4): 677-692
Mesoscale oceanographic features influence the composition of zooplankton. Cyclonic eddies can promote upwelling and production of gelatinous zooplankton, which play critical roles in ocean biogeochemical cycling. We examined variation in assemblages of thaliaceans (salps, doliolids and pyrosomes) among mesoscale oceanographic features at the tropical-temperate boundary of the East Australian Current (EAC) in Spring 2019 and Autumn 2021. The influence of cyclonic eddies was examined in a large offshore cyclonic eddy in 2019 and a newly formed frontal eddy in 2021. Pyrosomes were most abundant in the offshore EAC jet, and salps and doliolids were most abundant in coastal features, including within eddies that were transported offshore. In 2019, Salpa fusiformis increased 4-fold over 8 days in the large cyclonic eddy, and in 2021, doliolids increased > 50-fold over 2 weeks in a chlorophyll-rich coastal eddy while abundances of other thaliaceans remained unchanged or decreased. Correlations between abundances of thaliaceans and chlorophyll-a concentrations across the 102 samples collected during both voyages revealed that doliolids occupy a wider range of chlorophyll-a concentrations than salps. Our observations indicate that doliolids thrive in productive shelf environments, salps occur in less productive shelf waters and pyrosomes are most abundant in oligotrophic waters of the south Coral Sea.
View details for DOI 10.1093/plankt/fbad024
View details for PubMedID 37483906
View details for PubMedCentralID PMC10361811
Shortfalls in the protection of persistent bull kelp forests in the USA
View details for DOI 10.1016/j.biocon.2023.110133
- Spatial distribution of medusae (Cnidaria) assemblages in the southern Gulf of Mexico (dry season) COMMUNITY ECOLOGY 2022; 23 (1): 137-162
Symbiotic microalgae do not increase susceptibility of zooxanthellate medusae (Cassiopea xamachana) to herbicides
2021; 236: 105866
Herbicides are among the most detected pesticides in coastal environments. Herbicides may impact non-target organisms, but invertebrates that have a symbiotic relationship with microalgae (zooxanthellae) may be particularly susceptible. How zooxanthellae influence the response of organisms to herbicides, however, remains untested. We exposed zooxanthellate and azooxanthellate Cassiopea xamachana medusae to environmentally relevant concentrations of the herbicide atrazine (0 µg L - 1, 7 µg L - 1 and 27 µg L - 1) for 20 days. We hypothesised that atrazine would have adverse effects on the size, rate of bell contractions and, respiration of medusae, but that effects would be more severe in zooxanthellate than azooxanthellate medusae. We also predicted that photosynthetic efficiency, chlorophyll a (Chla) content and zooxanthellae density would decrease in zooxanthellate medusae exposed to atrazine. Both zooxanthellate and azooxanthellate medusae shrank, yet the size-specific respiration rates were not constant during the experiment. Photosynthetic efficiency of zooxanthellate medusae significantly decreased at 7 and 27 µgL-1 atrazine, but atrazine did not affect the Chla content or zooxanthellae density. Our results showed that even though atrazine inhibited photosynthesis, zooxanthellae were not expelled from the host. We conclude that the presence of zooxanthellae did not increase the susceptibility of C. xamachana medusae to atrazine.
View details for DOI 10.1016/j.aquatox.2021.105866
View details for Web of Science ID 000657603100002
View details for PubMedID 34052718
Chronic pesticide exposure elicits a subtle carry-over effect on the metabolome of Aurelia coerulea ephyrae
2021; 275: 116641
Chemical pollutants, such as pesticides, often leach into aquatic environments and impact non-target organisms. Marine invertebrates have complex life cycles with multiple life-history stages. Exposure to pesticides during one life-history stage potentially influences subsequent stages; a process known as a carry-over effect. Here, we investigated carry-over effects on the jellyfish Aurelia coerulea. We exposed polyps to individual and combined concentrations of atrazine (2.5 μg/L) and chlorpyrifos (0.04 μg/L) for four weeks, after which they were induced to strobilate. The resultant ephyrae were then redistributed and exposed to either the same conditions as their parent-polyps or to filtered seawater to track potential carry-over effects. The percentage of deformities, ephyrae size, pulsation and respiration rates, as well as the metabolic profile of the ephyrae, were measured. We detected a subtle carry-over effect in two metabolites, acetoacetate and glycerophosphocholine, which are precursors of the neurotransmitter acetylcholine, important for energy metabolism and osmoregulation of the ephyrae. Although these carry-over effects were not reflected in the other response variables in the short-term, a persistent reduction of these two metabolites could have negative physiological consequences on A. coerulea jellyfish in the long-term. Our results highlight the importance of considering more than one life-history stage in ecotoxicology, and measuring a range of variables with different sensitivities to detect sub-lethal effects caused by anthropogenic stressors. Furthermore, since we identified few effects when using pesticides concentrations corresponding to Australian water quality guidelines, we suggest that future studies consider concentrations detected in the environment, which are higher than the water quality guidelines, to obtain a more realistic scenario by possible risk from pesticide exposure.
View details for DOI 10.1016/j.envpol.2021.116641
View details for Web of Science ID 000625380600046
View details for PubMedID 33611208
Polyps of the Jellyfish Aurelia aurita Are Unaffected by Chronic Exposure to a Combination of Pesticides
ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY
2020; 39 (9): 1685-1692
Pesticides are a major contaminant in coastal waters and can cause adverse effects in marine invertebrates such as jellyfish. Most studies have investigated short-term responses of organisms to unrealistically high concentrations of pesticides; however, chronic exposure to persistent low concentrations, which are more likely to occur in the environment, are rarely analyzed. We tested the response of polyps of the moon jellyfish Aurelia aurita to environmental concentrations of the herbicide atrazine and the insecticide chlorpyrifos, individually and in combination, over 9 wk. We hypothesized that exposure to individual pesticides would reduce rates of asexual reproduction and alter polyps' metabolite profiles, and that the results would be more severe when polyps were exposed to the combined pesticides. Polyps survived and reproduced (through budding) in all treatments, and no differences among treatments were observed. Proton nuclear magnetic resonance spectroscopy revealed no difference in profiles of polar metabolites of polyps exposed to the individual or combined pesticides. Our results suggest that A. aurita polyps are unaffected by chronic exposure to atrazine and chlorpyrifos at concentrations recommended as being protective by current Australian water quality guidelines. Environ Toxicol Chem 2020;39:1685-1692. © 2020 SETAC.
View details for DOI 10.1002/etc.4750
View details for Web of Science ID 000538908900001
View details for PubMedID 32418248
- Marine heat waves threaten kelp forests. Science (New York, N.Y.) 2020; 367 (6478): 635
Review of the Phyllophoridae family (Holothuroidea: Dendrochirotida) in Mexican waters
REVISTA DE BIOLOGIA TROPICAL
2015; 63: 77-85
View details for Web of Science ID 000380019300009