Background
The authors write that "maternal effects are defined as cross-generation phenotypic plasticity, implying the capability of a mother to adjust the phenotype of her offspring [in] response to environmental cues that her offspring will encounter, in a manner that enhances offspring fitness (Parker and Begon, 1986; Lacey, 1998)," stating as an example that "Sydney rock oyster larvae are larger and develop faster in higher CO2 conditions, if the adults also have been incubated in high CO2 conditions (Parker et al., 2012)."

What was done
According to Vehmaa et al., they "tested the reproductive response of Acartia sp. calanoid copepods and the importance of maternal effects in determining the offspring quality in a changing environment according to a 2100 climate scenario of a pH decline by 0.4 unit and a temperature elevation of 3°C." This they did by monitoring the egg production of copepods incubated in four different pH and temperature conditions for five consecutive days, and on days 1, 3 and 5 dividing the eggs and allowing them to hatch in either the same or in different conditions than those in which they were produced.

What was learned
The three Finnish researchers report that "higher production temperature induced a positive maternal effect resulting in faster hatching and indicating that the mothers can invest more in their eggs, and therefore produce better quality eggs." In addition, they further note, in this regard, that the similar studies of Karell et al. (2008) and Jonasdottir et al. (2009) showed how "the egg quality in terms of maternal immunological or nutritional provisioning improved," and they suggest that this phenomenon may explain "the declining effect of pH difference on egg hatching."

What it means
Taken together, Vehmaa et al. conclude that these several observations demonstrate that maternal effects "are an important mechanism in the face of environmental change." Indeed, it would appear that they can actually spell the difference between extinction and survival in situations such as those that are typically forecast for earth's near future by the world's climate alarmists.

References
Jonasdottir, S.H., Visser, A.W. and Jespersen, C. 2009. Assessing the role of food quality in the production and hatching of Temora longicornis eggs. Marine Ecology Progress Series 382: 139-150.

Karell, P., Kontiainen, P., Pietiainen, H., Siitari, H. and Brommer, J.D. 2008. Maternal effects on offspring Igs and egg size in relation to natural and experimentally improved food supply. Functional Ecology 22: 682-690.

Lacey, E.P. 1998. What is an adaptive environmentally induced parental effect? In: Mousseau, T. and Fox, C.W. (Eds.). Maternal Effects as Adaptations. Oxford University Press, Oxford, United Kingdom, pp. 54-66.

Parker, G.A. and Begon, M. 1986. Optimal egg size and clutch size - effects of environment and maternal phenotype. American Naturalist 128: 573-592.

Parker, L.M., Ross, P.M., O'Connor, W.A., Borysko, L., Raftor, D.A. and Portner, H.-O. 2012. Adult exposure influences offspring response to ocean acidification in oysters. Global Change Biology 18: 82-92.