Effects of climate variability on transparency and thermal structure in subtropical, monomictic Lake Annie, Florida

Lake Annie is a small (37 ha), relatively deep (21 m) sinkhole lake on the Lake Wales Ridge (LWR) of central Florida with a long history of study, including monthly limnological monitoring since June, 1983. The record shows high variability in Secchi disc transparency, which ranged from < 1 to 15 m with a trend toward decreasing values over the latter decade of record. We examined available regional meteorological, groundwater and limnological data to determine the drivers and thermal consequences of variability in water transparency. While total nutrient concentrations and chlorophyll-a were highest during years of low transparency, stepwise regression showed that none of these had a signifi cant effect on transparency after water color was taken into account. Repeated years of high precipitation between 1993–2005 caused an increase in water table height, increasing the transport of dissolved substances from the vegetated watershed into the lake. Groundwater stage explained 73 % of the interannual variability in water transparency. Transparency, in turn, explained 85 % of the interannual variability in the heat budget for the lake, which ranged from 1.8 × 108 to 4.1 × 108 Joules m–2 yr–1, encompassing the range reported across Florida lakes. While surface water temperature was not affected by transparency, depths below 5 m warmed faster during the stratifi ed period during years having a lower rate of light extinction. We show that an increase in precipitation of 20 cm per year reduces the depth of the summer euphotic zone and thermocline by 1.9 and 1.6 m, respectively, and causes a 1-month reduction in the duration of winter mixing in this monomictic lake. Because biota have been shown to respond to shifts in light and heat distribution of much smaller magnitude than exhibited here, our work suggests that subtle changes in precipitation linked to climate fl uctuations may have signifi cant physical as well as biotic consequences.

Protecting Your Assets: A Well-Defined Credit Policy Is The Key

In - Protecting Your Assets: A Well-Defined Credit Policy Is The Key – an essay by Steven V. Moll, Associate Professor, The School of Hospitality Management at Florida International University, Professor Moll observes at the outset: “Bad debts as a percentage of credit sales have climbed to record levels in the industry. The author offers suggestions on protecting assets and working with the law to better manage the business.” “Because of the nature of the hospitality industry and its traditional liberal credit policies, especially in hotels, bad debts as a percentage of credit sales have climbed to record levels,” our author says. “In 1977, hotels showing a net income maintained an average accounts receivable ratio to total sales of 3.4 percent. In 1983, the accounts receivable ratio to total sales increased to 4.1 percent in hotels showing a net income and 4.4 percent in hotels showing a net loss,” he further cites. As the professor implies, there are ways to mitigate the losses from bad credit or difficult to collect credit sales. In this article Professor Moll offers suggestions on how to do that. Moll would suggest that hotels and food & beverage operations initially tighten their credit extension policies, and on the following side, be more aggressive in their collection-of-debt pursuits. There is balance to consider here and bad credit in and of itself as a negative element is not the only reflection the profit/loss mirror would offer. “Credit managers must know what terms to offer in order to compete and afford the highest profit margin allowable,” Moll says. “They must know the risk involved with each guest account and be extremely alert to the rights and wrongs of good credit management,” he advocates. A sound profit policy can be the result of some marginal and additional credit risk on the part of the operation manager. “Reality has shown that high profits, not small credit losses, are the real indicator of good credit management,” the author reveals. “A low bad debt history may indicate that an establishment has an overly conservative credit management policy and is sacrificing potential sales and profits by turning away marginal accounts,” Moll would have you believe, and the science suggests there is no reason not to. Professor Moll does provide a fairly comprehensive list to illustrate when a manager would want to adopt a conservative credit policy. In the final analysis the design is to implement a policy which weighs an acceptable amount of credit risk against a potential profit ratio. In closing, Professor Moll does offer some collection strategies for loose credit accounts, with reference to computer and attorney participation, and brings cash and cash discounts into the discussion as well. Additionally, there is some very useful information about what debt collectors – can’t – do!