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I had no idea what I was getting into when I decided to go into marine biology as a graduate student. It has ended up being a wonderful career, with opportunities to work with wonderful people around the world, and to work with many wonderful students at a variety of grade levels. It has also opened up opportunities in completely unexpected directions and allowed me to explore a good variety of research questions, explore a variety of teaching methods at a variety of grade levels, write a few books, and even develop some games for middle-school students. Luck has certainly played a role in some of this, but my main advice is to always keep an eye open for opportunities of interest, within and outside of your normal field…and seize them if possible!

 

As in lamellibranch bivalves, individuals of the common Atlantic slippersnailCrepidula fornicatabeat cilia on their gill filaments to produce a suspension‐feeding current. Having only one shell and no siphons with which to direct water flow, however, individuals ofC. fornicatamust adhere to a solid substrate to facilitate normal feeding. Thus, what hydrodynamic role does substrate attachment play in producing, regulating, and directing the suspension‐feeding current for this species? Here, a combined particle image velocimetry and computational fluid dynamics study was conducted to address this question. Three findings were obtained: (1) Juveniles ofC. fornicata(shell length 6.0–10.6 mm) whose foot was attached to a solid surface generated a strong, fan‐like exhalant current and an almost equally strong, convergent inhalant current, both being spatially well extended; (2) juveniles ofC. fornicatathat were prevented from adhering to any surface also generated a strong, fan‐like exhalant current but a much weaker and spatially limited inhalant current; and (3) whether or not they were attached to a solid surface, juveniles ofC. fornicatahad almost the same performance or system characteristics of the ciliary water pump, including the relationship between flow pressure rise Δpacross the ciliary zone and volume flow rateQ, pump resistance Δp/Q, and pressure coefficient for laminar flowC_p,l. These results indicate that the primary hydrodynamic effect of substrate attachment inC. fornicatais to form a complete inhalant chamber with a narrowed opening, such that negative flow pressure develops in the inhalant chamber, and a strong, convergent, spatially well‐extended inhalant current is generated to effectively bring in food particles from farther distances and to reduce refiltration of the outflowing water. Finally, ecological trade‐offs are discussed regarding the two distinct shell configuration strategies: (1) that of the single‐shelledC. fornicata, with only a naturally formed exhalant chamber and opening but not a morphologically defined inhalant chamber and opening, and (2) that of two‐shelled bivalves, with naturally formed exhalant and inhalant chambers.

 

Rising atmospheric CO 2 reduces seawater pH causing ocean acidification (OA). Understanding how resilient marine organisms respond to OA may help predict how community dynamics will shift as CO 2 continues rising. The common slipper shell snail Crepidula fornicata is a marine gastropod native to eastern North America that has been a successful invader along the western European coastline and elsewhere. It has also been previously shown to be resilient to global change stressors. To examine the mechanisms underlying C. fornicata’s resilience to OA, we conducted two controlled laboratory experiments. First, we examined several phenotypes and genome-wide gene expression of C. fornicata in response to pH treatments (7.5, 7.6, and 8.0) throughout the larval stage and then tested how conditions experienced as larvae influenced juvenile stages (i.e., carry-over effects). Second, we examined genome-wide gene expression patterns of C. fornicata larvae in response to acute (4, 10, 24, and 48 h) pH treatment (7.5 and 8.0). Both C. fornicata larvae and juveniles exhibited resilience to OA and their gene expression responses highlight the role of transcriptome plasticity in this resilience. Larvae did not exhibit reduced growth under OA until they were at least 8 days old. These phenotypic effects were preceded by broad transcriptomic changes, which likely served as an acclimation mechanism for combating reduced pH conditions frequently experienced in littoral zones. Larvae reared in reduced pH conditions also took longer to become competent to metamorphose. In addition, while juvenile sizes at metamorphosis reflected larval rearing pH conditions, no carry-over effects on juvenile growth rates were observed. Transcriptomic analyses suggest increased metabolism under OA, which may indicate compensation in reduced pH environments. Transcriptomic analyses through time suggest that these energetic burdens experienced under OA eventually dissipate, allowing C. fornicata to reduce metabolic demands and acclimate to reduced pH. Carry-over effects from larval OA conditions were observed in juveniles; however, these effects were larger for more severe OA conditions and larvae reared in those conditions also demonstrated less transcriptome elasticity. This study highlights the importance of assessing the effects of OA across life history stages and demonstrates how transcriptomic plasticity may allow highly resilient organisms, like C. fornicata , to acclimate to reduced pH environments.