Publication Date:
2024-03-15
Description:
Anthropogenic CO2 emissions cause a drop in seawater pH and shift the inorganic carbon speciation. Collectively, the term ocean acidification (OA) summarizes these changes. Few studies have examined OA effects on predatory plankton, e.g. Hydrozoa and fish larvae as well as their interaction in complex natural communities. Because Hydrozoa can seriously compete with and prey on other higher-level predators such as fish, changes in their abundances may have significant consequences for marine food webs and ecosystem services. To investigate the interaction between Hydrozoa and fish larvae influenced by OA, we enclosed a natural plankton community in Raunefjord, Norway, for 53 days in eight ≈ 58 m³ pelagic mesocosms. CO2 levels in four mesocosms were increased to ≈ 2000 µatm pCO2, whereas the other four served as untreated controls. We studied OA-induced changes at the top of the food web by following ≈2000 larvae of Atlantic herring (Clupea harengus) hatched inside each mesocosm during the first week of the experiment, and a Hydrozoa population that had already established inside the mesocosms. Under OA, we detected 20% higher abundance of hydromedusae staged jellyfish, but 25% lower biomass. At the same time, survival rates of Atlantic herring larvae were higher under OA (control pCO2: 0.1%, high pCO2: 1.7%) in the final phase of the study. These results indicate that a decrease in predation pressure shortly after hatch likely shaped higher herring larvae survival, when hydromedusae abundance was lower in the OA treatment compared to control conditions. We conclude that indirect food-web mediated OA effects drove the observed changes in the Hydrozoa – fish relationship, based on significant changes in the phyto-, micro-, and mesoplankton community under high pCO2. Ultimately, the observed immediate consequences of these changes for fish larvae survival and the balance of the Hydrozoa – fish larvae predator – prey relationship has important implications for the functioning of oceanic food webs.
Keywords:
Abundance per volume; Aglantha digitale; Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Aragonite saturation state, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Biomass/Abundance/Elemental composition; Calcite saturation state; Calcite saturation state, standard deviation; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Calculated using seacarb after Orr et al. (2018); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Chlorophyll a; Chlorophyll a, standard deviation; Clytia sp.; Coast and continental shelf; DATE/TIME; Day of experiment; Dry mass; Dry mass per individual; Entire community; Event label; Field experiment; Fish; Fjord; Fraction; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Fugacity of carbon dioxide in seawater, standard deviation; Growth/Morphology; Identification; Indeterminata; Individual dry mass; Individuals; KOSMOS_2015; KOSMOS_2015_Mesocosm-M1; KOSMOS_2015_Mesocosm-M2; KOSMOS_2015_Mesocosm-M3; KOSMOS_2015_Mesocosm-M4; KOSMOS_2015_Mesocosm-M5; KOSMOS_2015_Mesocosm-M6; KOSMOS_2015_Mesocosm-M7; KOSMOS_2015_Mesocosm-M8; KOSMOS_2015_Mesocosm-M9; KOSMOS Bergen; Length, standard; Mass per volume; MESO; Mesocosm experiment; Mesocosm label; Mesocosm or benthocosm; Method comment; Mortality/Survival; North Atlantic; Number of individuals; OA-ICC; Obelia geniculata; Ocean Acidification International Coordination Centre; Origin; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Potentiometric titration; Rathkea octopunctata; Ratio; Salinity; Salinity, standard deviation; Sample code/label; Sarsia tubulosa; Species; Status; Temperate; Temperature, water; Temperature, water, standard deviation; Time in days; Tomopteris sp.; Treatment; Treatment: partial pressure of carbon dioxide; Type; Volume
Type:
Dataset
Format:
text/tab-separated-values, 32668 data points
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