In situ imaging across ecosystems to resolve the fine‐scale oceanographic drivers of a globally significant planktonic grazer

Abstract

Doliolids are common gelatinous grazers in marine ecosystems around the world and likely influence carbon cycling due to their large population sizes with high growth and excretion rates. Aggregations or blooms of these organisms occur frequently, but they are difficult to measure or predict because doliolids are fragile, under sampled with conventional plankton nets, and can aggregate on fine spatial scales (1-10 m). Moreover, ecological studies typically target a single region or site that does not encompass the range of possible habitats favoring doliolid proliferation. To address these limitations, we combined in situ imaging data from six coastal ecosystems, including the Oregon shelf, northern California, southern California Bight, northern Gulf of Mexico, Straits of Florida, and Mediterranean Sea, to resolve and compare doliolid habitat associations during warm months when environmental gradients are strong and doliolid blooms are frequently documented. Higher ocean temperature was the strongest predictor of elevated doliolid abundances across ecosystems, with additional variance explained by chlorophyll a fluorescence and dissolved oxygen. For marginal seas with a wide range of productivity regimes, the nurse stage tended to comprise a higher proportion of the doliolids when total abundance was low. However, this pattern did not hold in ecosystems with persistent coastal upwelling. The doliolids tended to be most aggregated in oligotrophic systems (Mediterranea and southern California), suggesting that microhabitats within the water column favor proliferation on fine spatial scales. Similar comparative approaches can resolve the realized niche of fast-reproducing marine animals, thus improving predictions for population-level responses to changing oceanographic conditions.The environmental conditions associated with animal aggregations or population growth can indicate suitable or favorable habitat (Pulliam 2000; Treible et al. 2022).Describing these conditions is a necessary first step toward predicting how populations will respond to environmental change. For most marine animals, however, environmental

Western Boundary Current–Subtropical Continental Shelf Interactions

“…This is analogous to the trait-based approach to ecology, where organisms are pooled into functional categories based on their ecological roles within their environments (Kiorboe et al, 2018). This can also provide an approach for standardizing data collected with different methods and levels of taxonomic detail, as well as to compare across ecosystems to elucidate oceanographic drivers of common zooplankton traits or taxa (Greer et al, 2023).…”

Drivers of plankton community structure in intermittent and continuous coastal upwelling systems–from microbes and microscale in-situ imaging to large scale patterns

“…ISIIS is towed behind the ship at 2.5 m s -1 where it undulates on each cross-shelf transect between 1 m and 100 m depth or as close as 2 m above the seafloor in shallower water. ISIIS has been used in various ecosystems with differing scientific objectives, such as the investigation of larval fish distributions at eddy fronts (Schmid et al, 2020) and fine-scale plankton patchiness in the Straits of Florida (Robinson et al, 2021), larval fish distributions in the context of environmental gradients in the NCC (Briseño-Avena et al, 2020;Swieca et al, 2020), the investigation of zooplankton individual-level interactions and parasitism in the Gulf of Mexico (Greer et al, 2021), and crossecosystem comparisons of a gelatinous grazer (Greer et al, 2023).…”

Edge computing at sea: high-throughput classification of in-situ plankton imagery for adaptive sampling

“…Removal of these low-confidence images retains true spatial distributions (Faillettaz et al, 2016). The process and accuracies are described in more detail in previously published work (Briseño-Avena et al, 2020b;Schmid et al, 2020;Swieca et al, 2020;Schmid et al, 2021;Greer et al, 2023;Schmid et al, 2023b). The pipeline described here is open-sourced at: http://dx.doi.org/ 10.5281/zenodo.7739010.…”

“…As part of a study of the planktonic food web dynamics of this system, we used the high resolution In Situ Ichthyoplankton Imaging System-3 (ISIIS-3; Figure 1) to image plankton ranging from 250 µm to 15 cm, in their in-situ (i.e., natural) environment (Cowen and Guigand, 2008). While ISIIS was developed initially to enhance research of ichthyoplankton (i.e., larval fishes), it obtains images of plankters ranging from diatoms and protists to copepods, jellies, and larval fishes, and has been successfully deployed in a multitude of systems (e.g., the NCC, Swieca et al, 2020; the Straits of Florida, Robinson et al, 2021; and in the Gulf of Mexico and the Mediterranean, Greer et al, 2023).…”