Marine induced defenses

Keywords Marine chemical defense Activated defense Induced defense Plankton Chemical ecology... 

Graeve M, Dauby P, Scailteur Y (2001) Combined lipid, fatty acid and digestive tract content analyses a penetrating approach to estimate feeding modes of Antarctic amphipods. Polar Biol 24 853-862 Harvell CD (1990) The ecology and evolution of inducible defenses. Q Rev Biol 65 323-340 Hay ME (1996) Marine chemical ecology what s known and what s next J Exp Mar Biol Ecol 200 103-134... 

To date, no clear evidence of inducible defenses among freshwater macroalgae has been reported, in contrast to their marine algal counterparts. For example, certain species of marine brown algae increase phlorotannin production in response to damage by mesograzers (Amsler and Fairhead 2006 see Chaps. 3 and 7). Whether Chara and Cladophora, two species of freshwater chlorophytes with putative allelopathic activity, increase allelochemical concentration in response to competitors remains to be seen (see Sect. 5.7.3). 

Hansson, LA, Gustafsson S, Rengefors K, Bomark L (2007) Cyanobacterial chemical warfare affects zooplankton community composition. Freshwater Biol 52 1290-1301 Harvell CD (1986) The ecology and evolution of inducible defenses in a marine bryozoan cues, costs, and consequences. Am Nat 128 810-823... 

Specificity of molecular bioactivity and differentially induced defenses are only two examples of factors that can confound the interpretation of patterns at the macroscale. As our knowledge of marine systems continues to expand, the relative abundance of secondary metabolites in different geographic locations may be better understood. However, the literature supports the idea that local pressures and habitat, genetic composition, mode of response and metabolism of the algae play a significant role in shaping distribution patterns of secondary metabolites (e.g. Wright... 

This type of correlative approach is widespread, as only a few marine studies involving inducible defenses (and none with mobile invertebrates) have directly demonstrated that the induction results in a decrease in the susceptibility of the organism to predation.71,72 Statistically significant differences in shell thickness or concentrations of defensive chemicals may or may not meaningfully affect predator preferences in ecologically relevant field situations. For chemical defenses, compound dose-response relationships may be nonlinear, and threshold levels of defense could be sufficient to deter predators so that further induction has little additional benefit. Thus, future studies should focus on directly demonstrating whether an induced response reduces predation on prey organisms. 

While there are only a few cases of induction of chemical defenses among seaweeds, the phenomenon is very common among terrestrial plants." This discrepancy in the prevalence of inducible defenses in terrestrial vs. marine plants could be due to the different biologies of vascular terrestrial plants vs. nonvascular seaweeds (e.g., the induction stimulus from localized damage may not be efficiently translocated in seaweeds133), complex interactions between grazing damage and environmental conditions,161 or herbivore taxa studied,5 but the lesser amount of research on seaweeds relative to terrestrial plants may also explain much of the disparity. 

Cohen JB, Forward RB Jr (2005) Photobehavior as an inducible defense in the marine copepod Calanopia americana. Limnol Oceanogr 50 1269-1277... 

Harvell, C.D. 1992. Inducible defenses and allocation shifts in a marine bryozoan. Ecology 73 1567-1576. 

Toth GB, Pavia H (2000) Water-borne cues induce chemical defense in a marine alga (Ascophyllwn nodosum). Proc Natl Acad Sci USA 97 14418-14420... 

Until recently, a few inducers of ROS emission were recognized as true elicitors of defense responses in marine plant-microbe interactions, and these have already been discussed in previous reviews (Potin et al. 1999, 2002 Pohnert 2004 Dring 2006). This list has slightly increased recently (Table 12.1). 

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