Some say “environmental”, some say “ecological,” while others say “instream.” No matter which word you use, in general, these terms, coupled with the word “flow” are just different ways of describing the same thing: the amount of water in a river or stream needed to maintain healthy aquatic ecosystems. As Californians manage their state's natural river systems for flood control, hydropower and water supply, flows are increasingly a part of policy discussions. Today very few rivers in California flow to the ocean without barriers or interruptions. Instead, they are managed and regulated by a variety of state, federal and private agencies, with some of them mandated to have at least a minimum flow for environmental purposes.
The overbite clam, Corbula amurensis (Corbula), often blamed as one of the causes of the decline of the delta smelt, has further spread into the fresher portion of the San Francisco Bay Estuary in recent years.
This invasive species, which thrives in the saline waters of the estuary, arrived in 1986 in the midst of a serious drought, probably after being dumped with ships’ ballast water. The overbite clam consumes large amounts of plankton, a major food source for critical fish species – such as the delta smelt – and other aquatic organisms, by sucking in and filtering plankton from the water. The larger the geographic distribution of the clam, the more widespread its effects on the aquatic food web.
On July 9, scientists from the National Oceanic and Atmospheric Administration (NOAA) announced that an El Niño is forming in the Pacific Ocean, which can affect weather around the world. The most recent El Niño occurred in 2006.
El Niño is the large-scale climate phenomenon linked to periodic warming in sea surface temperatures in the eastern tropical Pacific Ocean. Its impacts depend on a variety of factors, such as intensity and extent of ocean warming and the time of year. Strong El Niño events can bring damaging winter storms in California and increased storminess – and water supply – across the southern United States, while weaker El Niños can actually result in below-normal rainfall for the same areas.
NOAA forecasters say that the sea surface temperature in June climbed to more than 1.5 degrees Fahrenheit above normal along a narrow band in the eastern equatorial Pacific. Forecasters expect this El Niño to continue developing during the next several months, and to last through winter 2009-10.
There are conflicting opinions on the eventual strength of this El Niño, but according to NOAA, current conditions and recent trends favor the continued development of a weak-to-moderate strength El Niño in the Northern Hemisphere in the fall.
What is the difference between native, non-native, endemic, and invasive species?