Planktonic primary production in a tidally influenced mangrove forest on the Pacific coast of Costa Rica.

Gocke, Klaus, Cortes, J. and Murrillo, M. M. (2001) Planktonic primary production in a tidally influenced mangrove forest on the Pacific coast of Costa Rica. Revista De Biologia Tropical, 49 (2). pp. 279-288.

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The seasonal variation of planktonic primary productivity was measured during one year in the main
channel in the interior part of the mangrove forest of the Estero de Morales (Estero de Punta Morales), a mangrove
system located in the Golfo de Nicoya at the Pacific coast of Costa Rica. Samples were incubated at the surface, 0.5
m and 1.0 m depth and the “light and dark bottle technique” was employed. The annual gross primary productivity
(PPg) was 457 and the net primary productivity (PPn) was 278 g C m–2 a-1. Daily PPg ranged from 0.29 to 3.88 and
PPn from 0.12 to 2.76 g C m-2 d-1. The highest rates observed in May and September were due to red tide blooms.
The seasonal variation of primary productivity inside the mangrove forest depends closely on the PP in the adjacent
area of the upper Golfo de Nicoya. Obviously the PP was light-limited since the compensation depth in the ebb
current was found at only 1m depth. In the flood current it was somewhat deeper. The planktonic primary
productivity inside the mangrove forest was completely restricted to the open channels. A simultaneous measurement
demonstrated that PPn of the phytoplankton could not take place under the canopy of the mangroves. Additional
studies on the time course of the oxygen concentration in the mouth of the main channel over 24 hrs demonstrated a
relation between the O2 and the tidal curves. The ebb current had always lower O2 concentrations than the flood
current, regardless of the time of the day. The difference to the foregoing high tide, however, was much smaller when
the low tide occurred during the day. This indicates that under the canopy the net primary production and hence O2
liberation of the attached macro- and microalgae, together with the high PPn of the phytoplankton in the channels,
helped the oxygen concentration not to decrease as far as during the night. Nevertheless it shows that the consumtion
of organic material in the submersed part of the mangrove forest exceeds always its production.

Document Type: Article
Keywords: Primary productivity, phytoplankton, oxygen concentration, mangrove forest, Golfo de Nicoya
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-MI Marine Microbiology
Refereed: No
ISSN: 0034-7744
Date Deposited: 18 Feb 2008 17:25
Last Modified: 14 Sep 2016 07:16

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