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The Changing Climate and Ecology in Narragansett Bay Candace Oviatt 10/12/12 Objective To examine some of the local environmental and ecological patterns in Rhode Island waters associated with the recent warming. NARRAGANSETT BAY Rhode Island Region Warm Cool Warm Climate Trends in Rhode Island Changes in the Narragansett Bay 1970s- 1990s Positive North Atlantic Oscillation - Biological Events (Winter water temperature increase of ~ +2.4 C in Narragansett Bay) 1) Winter flounder decrease perhaps due to predation by Crangon (sand shrimp) on the eggs. 2) American lobster and other decapods increase in Rhode Island waters. 3) The winter-spring bloom fails in warms years in Narragansett Bay. 4) Eelgrass beds after some recovery to the 1960s, again decline. 5) Change in jellyfish cycle of abundance: ctenophores become most abundant in early summer in contrast to former early fall abundance and prey upon copepods and larval fish in the water column. 6) Oysters re-populate Narragansett Bay in 1990s; southern oyster disease, Dermo, invades Rhode Island waters. 7) Increase in more southern species, like the smallmouth flounder. Winter flounder decrease perhaps due to predation by Crangon on the eggs and larvae. Collie et al. 2008: Abundance changes at the Fox Island station. Narragansett Bay Trawl Survey, total per decade 25000 20000 15000 Northern Searobin Lobster 10000 5000 0 60 - 70 70 - 80 80 - 90 90 - 00 10.00 8.00 6.00 4.00 Percent of Total Fox Island Trawl 14.00 Cancer Crbs Searobin 12.00 2.00 0.00 2001 1999 1997 1995 1993 1991 1989 1987 1985 1983 1981 1979 1977 1975 1973 1971 1969 1967 1965 1963 1961 1959 The winter-spring bloom fails in warms years in Narragansett Bay. From Nixon files Eelgrass beds now confined to the lower Bay. Bradley and Raposa 2007. Change in jellyfish cycle of abundance: ctenophores become most abundant in early summer in contrast to former early fall abundance and prey upon larval fish in the water column. Sulliv an, BK D Van Keuren, M C lancy (In press) Tim ing and size of bloo ms of the ctenopho re Mnemiopsis leidyi in relation to temp eratur e i n N arragansett Bay, RI Hyd robio logia Figure 1. Mnemiopsis leidyi . Pho to by H . Wes Pratt. Copepods Copepods Mnemiopsis leidyi Mnemiopsis leidyi Chl a Chl a Cold Winter J M M J S N Warm Winter J M M J S N Summary 1) Annual temperature has increased about 1oC, rainfall has increased about 25%, cloudy days have increased about 20%, and wind speed has decreased by about 20% since the 1950s. 2) New ecological patterns associated with warming in Rhode Island waters include: Decreased northern bottom fish; increased decapods, including lobster. Failure of the winter-spring bloom. Eelgrass decline. Changes in Ctenophore jellyfish cycles. Questions?