Water column and sediment nitrogen and phosphorus distribution patterns in the Florida Keys, USA

Szmant, Alina M.; Forrester, Amy

doi:10.1007/bf01626075

Cited by 130 publications

(91 citation statements)

References 38 publications

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“…and soluble reactive phosphorus.'' However, it is now widely accepted that reefs are not limited to low nutrient environments (see Hatcher [1997] and Szmant [1997] for reviews). For example, inshore fringing reefs on wide, shallow continental margins are naturally highly turbid and nutrient rich compared to oceanic atolls.…”

Section: Commentmentioning

confidence: 99%

“…comm.). Although upwelling is a major source of nutrients to these offshore reefs (Lee et al 1994;Szmant and Forrester 1996;Leichter et al 1996), Lapointe (1997) concluded that the ''bloom'' resulted from seepage of sewage-contaminated groundwater, invoking the elevated ␦ 15 N ratios of his June-August samples. No details were provided as to how the algae were collected for analysis, nor was any sampling done along spatial gradients postulated to represent exposure to contamination.…”

mentioning

confidence: 99%

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Algal blooms on coral reefs: What are the causes?

Hughes

Szmant

Steneck

et al. 1999

Limnology & Oceanography

172

110

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Section: Commentmentioning

confidence: 99%

mentioning

confidence: 99%

Algal blooms on coral reefs: What are the causes?

Hughes

Szmant

Steneck

et al. 1999

Limnology & Oceanography

172

110

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“…changes in land use and water management practices within southern Florida) time-scales (Fourqurean & Robblee 1999). These anthropogenic changes have led to a significant alteration in freshwater flow patterns within the Everglades, causing declines in seagrass distribution and abundance (Zieman et al 1989, Robblee et al 1991, Fourqurean et al 1993, increases in pelagic algae blooms (Butler et al 1995, Phlips et al 1995, Phlips & Badylak 1996, decreases in coral health (Chiappone & Sullivan 1994, Szmant & Forrester 1994, and economically important fisheries (e.g. Tortugas shrimp), (Nance 1994, Costello & Allen 1996, sport fisheries (Tilmant 1989) and manatees (McIvor et al 1994) within the bay.…”

mentioning

confidence: 99%

Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay

Glibert¹,

Heil²,

Hollander³

et al. 2004

Mar. Ecol. Prog. Ser.

169

121

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Florida Bay, a shallow, seagrass-dominated bay in southern Florida, USA, receives significant nutrient inputs and has experienced seagrass losses and microalgal blooms within the last several decades. Inorganic nutrient inputs have been well characterized, but the role of organic nutrients, specifically of dissolved organic nitrogen (DON) and organic phosphorus (DOP), in supporting microbial processes in the bay is unknown. In this study various techniques were used to assess the importance of these nutrients along a transect in Florida Bay when a cyanobacterial bloom occurred in the central region in November 2002. These techniques included measurements of ambient particulate and dissolved nutrients, enzyme (urease and alkaline phosphatase) activities, and experiments to determine rates of 15 N uptake (nitrate, ammonium, urea, and amino acids over a period of 0.5 h) and long-term (48 h) changes in microbial biomass and 15 N natural abundance in enrichment bioassays. The cyanobacterial bloom in central Florida Bay was associated with the highest concentrations of DON and DOP, whereas the microflagellate-and diatom-dominated eastern bay region was associated with the highest concentrations of inorganic nutrients. The zeaxanthin:chlorophyll a ratio (an indicator of the relative contribution of cyanobacteria to phytoplankton biomass) was positively correlated with the rate of uptake of urea, and negatively correlated with the rate of uptake of inorganic nitrogen. The opposite pattern was observed for the fucoxanthin:chlorophyll a ratio (indicative of relative diatom biomass) and the peridinin:chlorophyll a ratio (indicative of relative photosynthetic dinoflagellate biomass), suggesting that different algal groups were using different N substrates. Biomass responses in the bioassay experiments showed that phytoplankton (as chlorophyll a) responded to DON additions in the western region and to DOP additions in the eastern region, but heterotrophic bacteria, in contrast, responded to DOP additions in the west and DON additions in the east. These findings thus demonstrate the potential for different sources of N, including DON, to stimulate different components of the algal community, and for the phytoplankton and bacteria to respond differently to N and P.KEY WORDS: Florida Bay · Cyanobacteria · Organic N · Organic P · Nutrient limitation · Urease · Alkaline phosphatase · Bioassay · Nutrient uptake rates Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 280: [73][74][75][76][77][78][79][80][81][82][83] 2004 changes. Since the onset of industrialization in the 1880s, the health of the Florida Bay ecosystem has been negatively impacted on both decadal (e.g. increasing eutrophication) and centurial (e.g. changes in land use and water management practices within southern Florida) time-scales (Fourqurean & Robblee 1999). These anthropogenic changes have led to a significant alteration in freshwater flow patterns within the Everglades, causing declines in seagrass d...

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“…The water-quality debate is additionally fueled in Florida by reports of increased nutrient concentrations (Lapointe, O'Connell, and Garrett 1990), the presence of viral tracers (Paul et al 1995) and fecal indicator bacteria (Paul et al 1997) that are detectable in nearshore waters and corals (Lipp et al 2002), but other studies have not found increased nutrients or these microbial constituents in offshore waters or sediments (Szmant and Forrester 1996), seagrass beds (Fourqurean and Zieman 2002), or algae (Hanisak and Siemon 1999). A threeyear study of nearshore waters (Keller and Itkin 2002) throughout the Keys found that total nitrogen and phosphorus concentrations did not differ significantly between developed and undeveloped shorelines, although variability was high.…”

Section: Water Qualitymentioning

confidence: 99%

“…Ward-Paige, Risk, and Sherwood (2005) (1) variable isotopic signals for sewage that are not always heavy; (2) δ 15 N results measured for particulate organic material that did not differ along nearshore to offshore transects throughout the Keys; and (3) discovery that the δ 15 N of particulate organic matter from inshore stations is largely derived from seagrasses and macroalgae, not sewage. Even if sewage pollution makes its way to offshore reefs, the amount supplied must be measured relative to substantial natural nutrient sources due to Gulf Stream flow, tidal flushing (Szmant and Forrester 1996), and upwelling (Leichter, Stewart, and Miller 2003). The Gulf Stream and tidal movements must also be considered a diluting influence relative to potential sewage inputs.…”

Section: Water Qualitymentioning

confidence: 99%