PDF | Lakes occupy about 1.8 % of the earth’s surface. Mean summertime plankton respiration (R) and photosynthesis (P) in surface waters of lakes as a function of chlorophyll concentration, an index of overall lake productivity (del Georgio & Peters, 1994). Is it good or bad when, e.g., land gets flooded to create a reservoir? 163–186 q 2001 by the ecological society of america trophic cascades, nutrients, and lake productivity: whole-lake experiments stephen r. carpenter,1,6 jonathan j. cole,2 james r. hodgson,3 james f. k itchell,1 michael l. pace,2 darren bade,1 kathryn l. cottingham,4 timothy e. essington,1 jeffrey n. houser,1 and daniel e. schindler5 Fish production in these lakes is generally high, e.g. It should be noted that in the more ecologically mature Lakes Malawi and Victoria, fish productivity is less than 50 kg ha-1. Lake surface area relative to upstream catchment size and lake perimeter‐to‐surface‐area ratio were also important, with smaller upstream catchments yielding higher production, and high shoreline complexity correlated with lower productivity as measured by limnetic PR. This production is important because some of it is used for food and some is valued for recreation, it is a direct measure of total ecosystem processes, and it … But as the annual relative yield from the highly diverse ﬂood-regulation, then both external and internal impacts of and variable African lakes practically is constant around three ton changed or regulated water level dynamics on the aquatic biology per ﬁsher per year (Fig. ... (the relative depth of t he lake has a . ... continuum of productivity. About 280 000 cu.km of water exists on earth in the form of lakes. 163 ecological monographs, 71(2), 2001, pp. Jeppe Kolding, Paul A.M. van Zwieten, Relative lake level fluctuations and their influence on productivity and resilience in tropical lakes and reservoirs, Fisheries Research, 10.1016/j.fishres.2011.11.008, 115-116, (99-109), (2012). Lake productivity also influences δ 13 C patterns, as France et al. 3.2 Lakes … relative to the atmosphere. Because lake productivity was measured solely by water column chlorophyll a in this study, this weak causality is expected. Relative lake level fluctuations and their influence on productivity and resilience in tropical lakes and reservoirs. Do lakes have lower or higher primary and secondary productivity per unit area compared with land? Lake thermal structure is determined by several factors. 7.12. Land vs. lake productivity. A broader definition of lake productivity, that is, incorporating factors operating outside of water column (e.g., riparian meadows and mudflats), would result in a closer relationship and higher model performance. The index also has a strong log-linear relationship with the fish productivity. The thermal structure of lakes helps determine productivity and nutrient cycling. Lakes receive the vast majority of their heat at the surface from solar heating. Fig. Lake Kyoga (389 kg ha-1, Lake George 156 kg ha-1 and Lake Mweru Wantipa 100 kg ha-1). Biological production represents the total amount of living material (biomass) that was produced during a defined period of time.