Clam larvae’s acidification tolerance fails to predict later resilience
A peer-reviewed experiment found that clam families coping best with acidified seawater as larvae often performed poorly after metamorphosis. Across 51 families, the pattern challenges assessments based on just one life stage. The experiment concerns one population and one acidification intensity, while a separate simulation explores possible consequences of selecting for only part of the life cycle.
Science··Evening
The best-performing families change after metamorphosis
Clam families that tolerated acidified seawater well as larvae often lost that advantage after metamorphosis. A peer-reviewed experiment in PLOS Biology found a negative relationship between tolerance scores at the two developmental stages. The work concerns the hard clam Mercenaria mercenaria, a marine bivalve whose early and later forms have different physiological demands.[1], [2]
Of 13 families in the best-performing quarter at the larval stage, 10 fell below the later-stage median. None ranked in the top quarter at both stages. Across families, the correlation was −0.530, with a 95% confidence interval from −0.691 to −0.332. The same pronounced opposition between stages was absent in ambient seawater.[1]
Matched families connect separate experiments
Researchers compared 51 families descended from 12 males and six females under present-day and end-century acidification conditions. Different individuals from the same families entered the larval and post-metamorphic experiments, so family membership connects the measurements. Larval outcomes included survival, shell properties and time to metamorphosis. Later measurements included growth, shell dissolution and oxygen uptake.[1]
Reproductive tissue was assessed after a 90-day acidification nursery period and two years of growth in a shared ambient environment. The experiment sampled one source population at one acidification intensity. Family differences may include maternal and nonadditive effects; the study did not identify genes responsible for the cross-stage pattern.[1]
A simulation explores selection across the life cycle
A separate simulation spanning 20 generations examined the possible cost of favouring tolerance at only one stage. Balanced attention to multiple stages better preserved family diversity in the model. It held the family pool fixed and excluded mutation, recombination and migration, comparing selection directions rather than forecasting abundance. The authors connect the findings to broodstock assessment and climate-resilience screening, where choosing families solely by larval performance could discard diversity useful after metamorphosis. Replication across populations and conditions is needed before extending the pattern more broadly.[1]
