Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Oceanologia

2 2015

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Response patterns of phytoplankton growth to variations in resuspension in the German Bight revealed by daily MERIS data in 2003 and 2004

Su J., Tian T., Krasemann H., Schartau M., Wirtz K.

Oceanologia

2015

No. 57 (4)

328--341

Chlorophyll (chl a) concentration in coastal seas exhibits variability on various spatial and temporal scales. Resuspension of particulate matter can somewhat limit algal growth, but can also enhance productivity because of the intrusion of nutrient-rich pore water from sediments or bottom water layers into the whole water column. This study investigates whether characteristic changes in net phytoplankton growth can be directly linked to resuspension events within the German Bight. Satellite-derived chl a were used to derive spatial patterns of net rates of chl a increase/decrease (NR) in 2003 and 2004. Spatial correlations between NR and mean water column irradiance were analysed. High correlations in space and time were found in most areas of the German Bight (R2 > 0.4), suggesting a tight coupling between light availability and algal growth during spring. These correlations were reduced within a distinct zone in the transition between shallow coastal areas and deeper offshore waters. In summer and autumn, a mismatch was found between phytoplankton blooms (chl a > 6 mg m−3) and spring-tidal induced resuspension events as indicated by bottom velocity, suggesting that there is no phytoplankton resuspension during spring tides. It is instead proposed here that frequent and recurrent spring-tidal resuspension events enhance algal growth by supplying remineralized nutrients. This hypothesis is corroborated by a lag correlation analysis between resuspension events and in-situ measured nutrient concentrations. This study outlines seasonally different patterns in phytoplankton productivity in response to variations in resuspension, which can serve as a reference for modelling coastal ecosystem dynamics.

Making coastal research useful – cases from practice

Storch H., Emeis K., Meinke I., Kannen A., Matthias V., Ratter B. M. W., Stanev E., Weisse R., Wirtz K.

Oceanologia

2015

No. 57 (1)

3--16

Coastal research deals with that part of the sea, which is significantly affected by the land, and the part of the land, which is significantly affected by the sea. Coasts are in most cases densely populated, and the activities of people are shaping and changing the land/seascape of the coast. Thus, coast encompasses the coastal sea, the coastal land, coastal flora and fauna, and people. Since peoples’ economic and political preferences change and compete, the human impact on the coast changes is contested and subject to societal decision making processes. While some coastal research can help informing and constraining such decisions, many legitimate scientific efforts have little bearing on society. All decision making processes are political, so that scientific knowledge is not the dominant driver in such processes. Using cases from the Institute of Coastal Research of Helmholtz Zentrum Geesthacht, we describe some of these potentially useful parts of science, and discuss under which circumstances the potential usefulness transform into real utility. These cases do not span the full range of coastal science. Important issues are the recognition of alternative knowledge claims, the inevitableness of uncertainties and incompleteness of scientific analysis, the acceptance of the political nature of decisions and the ubiquitous presence of social values. Modesty, self-reflexivity and skepticism are needed on the side of science and an organized exchange with stakeholders and public through designated “border” services.