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- Ice ages and ecological transitions on temperate coasts
- Organisms face continual fluctuations in global climatic processes to which they must adapt or perish. Considering that many species are key habitat formers and energy producers, such responses to climate change can have significant population, community and even ecosystem consequences. Paleo-records of ecosystem responses to past environmental variability have proven invaluable for studying impacts of climate change on natural systems, yet such records are almost completely lacking for temperate benthic marine systems. Here, we bring together recent advances in paleoclimatology, coastal geomorphology, paleoceanography and archaeology for a well-studied region (the Southern California Bight, USA). We argue that there is now enough evidence to show that late-Quaternary sea-level rise over the past 18 500 years has caused a large-scale ecological shift in this region from highly productive rocky reefs to less productive sandy shores. Our integrated approach has implications for other temperate coastlines and helps provide insight into the interactions between human culture, biological communities and their environments., Cited By (since 1996):52, CODEN: TREEE
- Graham, Dayton, Erlandson
- Arrested development of giant kelp (Macrocystis pyrifera, Phaeophyceae) embryonic sporophytes: A mechanism for delayed recruitment in perennial kelps?
- Delayed recruitment of microscopic stages in respouse to cyclical cues is critical to the population dynamics of many annual and seasonally reproducing perennial seaweeds. Microscopic stages may play a similar role in continuously reproducing perennials in which adult sporophytes are subject to episodic mortality, if they can respond directly to the unpredictable onset and relaxation of unfavorable conditions. We experimentally evaluated the potential for temporary reduction in limiting resources (light, nutrients) to directly delay recruitment of giant kelp (Macrocystis pyrifera (L.) C.A. Agardh) gametophytes and embryonic sporophytes. Laboratory cultures were subjected to limiting conditions of light and nutrients for 1 month and then exposed to non-limiting conditions for 10 days. Gametophytes in all treatments failed to recruit to sporophytes after 2 weeks, suggesting they are not a source of delayed recruitment in giant kelp. Sporophytes in light-limited treatments, however, survived and grew significantly slower than non-light-limited controls. When stimulated with light, light-limited sporophytes grew from 2 to >10 times faster than unstimulated controls depending on nutrient availability. These results suggest that limiting resources can delay recruitment of embryonic giant kelp sporophytes for at least 1 month. Flexible timing of recruitment from embryonic sporophytes may enhance persistence of continuously reproducing perennial species when macroscopic adults are subject to episodic large-scale removals., Cited By (since 1996):24, Seaweeds, CODEN: JPYLA
- Kinlan, Graham, Sala, Dayton