Impact of rainwater hydrogen peroxide on chlorophyll a content of surface Gulf Stream seawater off North Carolina, USA

Abstract

Bioassays indicate addition of hydrogen peroxide in concentrations similar to rain sometimes decreases chlorophyll a (chl a) production in surface Gulf Stream seawater. Bioassays were conducted on shipboard in the spring and autumn of 1993, 1994, and 1995. using surface Gulf Stream seawater collected off the coast of North Carolina. Chl a increases were observed after addition of FeC13 (in 1 of 5 bioassays), iron (111) EDTA (6 of 6 bioassays), or EDTA alone (4 of 4 bioassays). The chl a increases were suppressed significantly in 7 of 11 of these bioassays when the bioassay seawater was initially diluted by 1 % with a 30 or 40 p M solution of hydrogen peroxide (a concentration similar to rainwater). Hydrogen peroxide induced inhibition of chl a production was not observed in bioassays in w h~c h chl a increased in response to addltion of nitrate or ammonium, hence the growth inhibition was associated with added metal or complexing agent. Rainwater therefore plays a complex role in primary productivity in surface seawater, with the specific effect dependent upon rainwater concentrations of nitrate, ammonium, trace metals and hydrogen peroxide, as well as on the extent of nitrogen limitation and the oxidant concentration in the surface seawater.

Flux and bioavailability of Cape Fear River and rainwater dissolved organic carbon to Long Bay, southeastern United States

“…This is significant because once it is deposited in coastal waters, the highly bioavailable rainwater DOC is likely to fuel secondary productivity. Various effects of rainwater on primary productivity have been documented [ Paerl , 1985; Willey and Paerl , 1993; Paerl and Fogel , 1994, Fogel et al , 1999, Willey et al , 1999]; however, the impact of the labile DOC in rainwater on secondary productivity has not been examined.…”

Influence of the ITCZ on H2O2 in near surface waters in the equatorial Atlantic Ocean

“…In the present work we examined the vertical distribution and inventory of H 2 O 2 in near surface seawater across the Equatorial Atlantic at 10°N as part of the German SOLAS programme. One of the aims of SOLAS is to understand the influence of atmospheric deposition on the biogeochemistry in the ocean; H 2 O 2 is an important species in this regard because of its potential influence on trace metal redox cycling [ Moffett and Zika , 1987; Croot et al , 2004] and on phytoplankton productivity [ Willey et al , 1999].…”

Evidence That an Optical Tail in the Gulf of Mexico After Tropical Cyclone Isaac was the Result of Offshore Advection of Coastal Water

“…However, in this case, determining advection of the high Chl-a feature from the delta to the open GoM using sequential images from satellites with visible band sen-sors is difficult due to the cloudiness of the images and the various possible contributors to elevated Chl-a (e.g., dissolved inorganic nitrogen and iron concentrated in rain stimulate primary production in the ocean; Paerl et al, 1999;Willey et al, 1999). However, clouds do not attenuate L-band radiation, so the L-band radiometers on the satellite missions for sea surface salinity (SSS) [e.g., European Space Agency Soil Moisture and Ocean Salinity (SMOS) and NASA Aquarius/SAC-D (Satélite Aplicaciones Científicas-D) mission] may be useful for finding evidence of plume advection (Kerr et al, 2010;Lagerloef et al, 2008).…”