Climate Change, Zooplankton and Fisheries

Dam, Hans G.; Baumann, Hannes

doi:10.1002/9781119154051.ch25

Cited by 24 publications

(24 citation statements)

References 165 publications

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“…Copepods are the most abundant metazoans in the ocean (Humes, ; Turner, ). They play an important role in transferring energy from primary producers to secondary consumers and are therefore tightly linked to global biogeochemical systems (Menden‐Deuer & Kiørboe, ), marine trophic webs (Turner, ), and commercial fisheries (Castonguay, Plourde, Robert, Runge, & Fortier, ; Dam & Baumann, ; Friedland et al, ). Studies of thermal adaptation in copepods have a long history (Bradley, ; Lonsdale & Levinton, ), but local adaptation has largely been ignored, especially in pelagic species (but see, Smolina, Harmer, Lindeque, & Hoarau, ).…”

Section: Introductionmentioning

confidence: 99%

Integrating patterns of thermal tolerance and phenotypic plasticity with population genetics to improve understanding of vulnerability to warming in a widespread copepod

Sasaki

Dam

2019

Global Change Biology

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Differences in population vulnerability to warming are defined by spatial patterns in thermal adaptation. These patterns may be driven by natural selection over spatial environmental gradients, but can also be shaped by gene flow, especially in marine taxa with high dispersal potential. Understanding and predicting organismal responses to warming requires disentangling the opposing effects of selection and gene flow. We begin by documenting genetic divergence of thermal tolerance and developmental phenotypic plasticity. Ten populations of the widespread copepod Acartia tonsa were collected from sites across a large thermal gradient, ranging from the Florida Keys to Northern New Brunswick, Canada (spanning over 20° latitude). Thermal performance curves (TPCs) from common garden experiments revealed local adaptation at the sampling range extremes, with thermal tolerance increasing at low latitudes and decreasing at high latitudes. The opposite pattern was observed in phenotypic plasticity, which was strongest at high latitudes. No relationship was observed between phenotypic plasticity and environmental variables. Instead, the results are consistent with the hypothesis of a trade-off between thermal tolerance and the strength of phenotypic plasticity. Over a large portion of the sampled range, however, we observed a remarkable lack of differentiation of TPCs. To examine whether this lack of divergence is the result of selection for a generalist performance curve or constraint by gene flow, we analyzed cytochrome oxidase I mtDNA sequences, which revealed four distinct genetic clades, abundant genetic diversity, and widely distributed haplotypes. Strong divergence in thermal performance within genetic clades, however, suggests that the pace of thermal adaptation can be relatively rapid. The combined insight from the laboratory physiological experiments and genetic data indicate that gene flow constrains differentiation of TPCs. This balance between gene flow and selection has implications for patterns of vulnerability to warming. Taking both genetic differentiation and phenotypic plasticity into account, our results suggest that local adaptation does not increase vulnerability to warming, and that low-latitude populations in general may be more vulnerable to predicted temperature change over the next century.

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Section: Introductionmentioning

confidence: 99%

Integrating patterns of thermal tolerance and phenotypic plasticity with population genetics to improve understanding of vulnerability to warming in a widespread copepod

Sasaki

Dam

2019

Global Change Biology

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“…Performance curves, i.e. the curve illustrating the effect of a climatic variable like temperature on a physiological rate, are often bell-shaped ( Dam and Baumann, 2018 ). However, previous studies on copepods have reported a positive linear or power relationship between investigated temperatures and egg development times (e.g.…”

Section: Resultsmentioning

confidence: 99%

Temperature-dependent egg production and egg hatching rates of small egg-carrying and broadcast-spawning copepods Oithona similis, Microsetella norvegica and Microcalanus pusillus

Barth-Jensen

Koski

Varpe

et al. 2020

Journal of Plankton Research

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Reproductive rates of copepods are temperature-dependent, but poorly known for small copepods at low temperatures, hindering the predictions of population dynamics and secondary production in high-latitude ecosystems. We investigated egg hatching rates, hatching success and egg production of the small copepods Oithona similis and Microsetella norvegica (sac spawners) and Microcalanus pusillus (broadcast spawner) between March and August. Incubations were performed at ecologically relevant temperatures between 1.3 and 13.2°C, and egg production rates were calculated. All egg hatching rates were positively correlated to temperature, although with large species-specific differences. At the lowest temperatures, M. pusillus eggs hatched within 4 days, whereas the eggs from sac spawners took 3–8 weeks to hatch. The egg hatching success was ≤25% for M. pusillus, >75% for O. similis and variable for M. norvegica. The maximum weight-specific egg production rate (μg C μg−1 C d−1) of M. pusillus was higher (0.22) than O. similis (0.12) and M. norvegica (0.06). M. norvegica reproduction peaked at 6–8°C, the prevailing in situ temperatures during its reproductive period. The difference in reproductive rates indicates species-specific thermal plasticity for the three copepods, which could have implications for present and future population dynamics of the species in arctic fjords.

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“…Yet, copepods are the most abundant metazoans in the oceans 27 , which play pivotal roles in pelagic trophodynamic 28 , biogeochemical cycles 29 and ecosystem services 30 . The consensus from copepod studies is that adult stages are resilient to OA 31,32 . However, very few of these studies are from field observations.…”

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Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system

Aguilera

Vargas

Dam

2020

Sci Rep

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Linking pH/pco 2 natural variation to phenotypic traits and performance of foundational species provides essential information for assessing and predicting the impact of ocean acidification (OA) on marine ecosystems. Yet, evidence of such linkage for copepods, the most abundant metazoans in the oceans, remains scarce, particularly for naturally corrosive Eastern Boundary Upwelling systems (EBUs). This study assessed the relationship between pH levels and traits (body and egg size) and performance (ingestion rate (IR) and egg reproduction rate (EPR)) of the numerically dominant neritic copepod Acartia tonsa, in a year-round upwelling system of the northern (23° S) Humboldt EBUs. The study revealed decreases in chlorophyll (Chl) ingestion rate, egg production rate and egg size with decreasing pH as well as egg production efficiency, but the opposite for copepod body size. Further, ingestion rate increased hyperbolically with Chl, and saturated at ~1 µg chl. L −1. Food resources categorized as high (H, >1 µg L −1) and low (L, <1 µg L −1) levels, and pH-values categorized as equivalent to present day (≤400 µatm pco 2 , pH > 7.89) and future (>400 µatm pco 2, pH < 7.89) were used to compare our observations to values globally employed to experimentally test copepod sensitivity to OA. A comparison (PERMANOVA) test with Chl/pH (2*2) design showed that partially overlapping OA levels expected for the year 2100 in other ocean regions, low-pH conditions in this system negatively impacted traits and performance associated with copepod fitness. However, interacting antagonistically with pH, food resource (Chl) maintained copepod production in spite of low pH levels. Thus, the deleterious effects of ocean acidification are modulated by resource availability in this system.

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Climate Change, Zooplankton and Fisheries

Cited by 24 publications

References 165 publications

Integrating patterns of thermal tolerance and phenotypic plasticity with population genetics to improve understanding of vulnerability to warming in a widespread copepod

Integrating patterns of thermal tolerance and phenotypic plasticity with population genetics to improve understanding of vulnerability to warming in a widespread copepod

Temperature-dependent egg production and egg hatching rates of small egg-carrying and broadcast-spawning copepods Oithona similis, Microsetella norvegica and Microcalanus pusillus

Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system

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