Traditional limnological studies have focused on extant, large and deep
bodies of fresh water. For over 70 years a strong positive relationship
between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has
been established in temperate lakes with phosphorus generally viewed as
the most limiting factor to productivity (Deevey 1940, Schindler 1977).
Over the last few decades however,
... [Show full abstract] investigations have expanded to
include the examination of shallow lakes, particularly in terms of water
quality, nutrient content and regime shifts between stable alternate
states. Most of these studies, however, have focused on northern, high
latitude regions where the lakes are typically postglacial, isolated and
fed by small streams. Relatively little work has been done on oxbow
lakes which are floodplain lakes and are semi or permanently connected
to the river. Oxbow lakes have been shown to serve several important
ecologic and economic functions including nurseries for young fish,
feeding grounds for top aquatic predators and increasing the
biodiversity of the landscape particularly in tropical regions of the
world where high precipitation and large rivers have produced thousands
of oxbow lakes. In many developing countries oxbow lakes are an
important source of revenue through fishing. This study examined the
relationship between nutrients and productivity in oxbow lakes globally
through a wide-spread literature synthesis. Four hundred and twenty nine
oxbow lakes were represented by 205 data points while 285 data points
represented 156 non-floodplain lakes. Despite differences in latitude,
lake size and climate we find that oxbow lakes globally have a
significantly less steep slope in their TP/Chl relationship than
non-floodplain lakes do indicating that the same amount of sestonic
phosphorus results in lower productivity. Oxbow lakes (TP/Chl): r =
0.7676, slope = 0.7257, Non-floodplain lakes (TP/Chl): r = 0.8096, slope
= 1.1309. We theorize that their connection to the river allows for
frequent inundation of turbid water and resuspension of lake sediment,
increasing nutrient levels but decreasing light penetration and algae
growth thus limiting productivity.