Knauss legislative fellowships in Congress help build careers — and they're fun and educational. See our video and fact sheet for details.
Research Publications: UM-SG-RS-2018-16
Title:
Reproductive isolation and morphological divergence between cryptic lineages of the copepod Acartia tonsa in Chesapeake BayYear:
2018Authors:
Plough, LV; Fitzgerald, C; Plummer, A; Pierson, JJSource:
Marine Ecology Progress Series 597 : 99 - 113DOI:
10.3354/meps12569Abstract:
Recent advances in molecular technologies have revealed cryptic species across many marine zooplankton taxa. However, the patterns and drivers of cryptic divergence are complex, and few studies have examined reproductive status among lineages through crosses. In this study, we performed pair crosses within and between 2 deeply divergent (cryptic) lineages (named 'fresh' [F] and 'salt' [S]) of the estuarine copepod Acartia tonsa from upper Chesapeake Bay, USA, to examine egg production and hatching rate. We also examined differences in morphology (prosome length) and chemical composition of the 2 lineages. Crossing experiments revealed that egg production did not differ among cross types but hatching rate was significantly lower for the between-lineage crosses (mean hatching rate of 0.02 for FxS vs. 0.46 and 0.52 for FxF and SxS, respectively). The nearly complete lack of nauplii production for between-lineage crosses suggests strong reproductive isolation, which supports previous molecular data. Significant differences between the lineages in size (F lineage is 13-14% shorter) and chemical com position (F lineages have 70% less carbon per copepod) may indicate pre-zygotic barriers to reproduction (e.g. morphological or gametic incompatibility). Overall, based on the crossing, mor phological, and chemical data reported here, and synthesizing previous biological data on the F and S lineages, we suggest that these cryptic lineages are likely to be separate, reproductively isolated species. Further work examining how divergent lineages of A. tonsa respond to environmental change and how they differ in their quality as prey items will be important for understanding trophic dynamics in estuarine environments like Chesapeake Bay.Maryland Sea Grant Topic(s):
'Related Research Project(s)' link to details about research projects funded by Maryland Sea Grant that led to this publication. These details may include other impacts and accomplishments resulting from the research.
'Maryland Sea Grant Topic(s)' links to related pages on the Maryland Sea Grant website.
Program Announcements
News and Blogs
Featured Fellow
Leone Yisrael is a cephalopod-loving scuba diver, cook, and loves to try new activities. She conducts genetic analysis and fieldwork at the Smithsonian Environmental Research Center through the Coastal Disease Ecology Lab.
Featured Research Project
Exploring the Use of Benthic Microbial Fuel Cells to Remove Sulfide While Harvesting Energy from Oyster Aquaculture Biodeposits
Oyster aquaculture is a rapidly growing industry in Maryland’s Chesapeake waters which stimulates economic activity and may provide a host of ecosystem benefits. A potential concern associated with the intensification of the oyster aquaculture is the local production and accumulation of oyster biodeposits, which can lead to a porewater sulfide accumulation and declining bioturbation, symptoms of declining ecosystem function. Sulfide is naturally removed from the seafloor by the interactions between bioturbating infauna and sulfide oxidizing bacteria.
Chesapeake Quarterly Magazine
A Growing Industry: Advancing Oyster Aquaculture in Maryland
